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Message-ID: <20140603113505.GA23308@gmail.com>
Date: Tue, 3 Jun 2014 13:35:05 +0200
From: Ingo Molnar <mingo@...nel.org>
To: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: linux-kernel@...r.kernel.org,
"Paul E. McKenney" <paulmck@...ibm.com>,
Peter Zijlstra <a.p.zijlstra@...llo.nl>,
Thomas Gleixner <tglx@...utronix.de>,
Andrew Morton <akpm@...ux-foundation.org>
Subject: [GIT PULL] RCU changes for v3.16
Linus,
Please pull the latest core-rcu-for-linus git tree from:
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git core-rcu-for-linus
# HEAD: e14505a8d50882ff3bdd4b791b14d90a0881fa4d Merge branch 'rcu/next' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/rcu
The main RCU changes in this cycle were:
- RCU Torture-test changes.
- Variable-name renaming cleanup.
- Update RCU documentation.
- Miscellaneous fixes.
- Patch to suppress RCU stall warnings while sysrq
requests are being processed.
Thanks,
Ingo
------------------>
Andreea-Cristina Bernat (3):
rcu: Add event tracing to dyntick_save_progress_counter().
rcu: Consolidate kfree_call_rcu() to use rcu_state pointer
rcu: Merge rcu_sched_force_quiescent_state() with rcu_force_quiescent_state()
Christoph Lameter (1):
rcu: Replace __this_cpu_ptr() uses with raw_cpu_ptr()
Eric Dumazet (1):
softirq: A single rcu_bh_qs() call per softirq set is enough
Himangi Saraogi (2):
rcu: Protect uses of ->jiffies_stall with ACCESS_ONCE()
rcu: Replace NR_CPUS with nr_cpu_ids
Iulia Manda (4):
rcu: Remove unused rcu_data structure field
rcu: Protect uses of jiffies_stall field with ACCESS_ONCE()
rcu: Remove "extern" from function declaration in include/linux/rcupdate.h
torture: Notice if an all-zero cpumask is passed inside a critical section
Liu Ping Fan (1):
rcu: Fix incorrect notes for code
Paul E. McKenney (49):
documentation: Update sysfs path for rcu_cpu_stall_suppress
documentation: Record rcu_dereference() value mishandling
documentation: Update API documentation
rcu: Protect ->gp_flags accesses with ACCESS_ONCE()
rcu: Print negatives for stall-warning counter wraparound
rcu: Update cpu_needs_another_gp() for futures from non-NOCB CPUs
rcu: Make callers awaken grace-period kthread
rcu: Document RCU_INIT_POINTER()'s lack of ordering guarantees
rcu: Bind RCU grace-period kthreads if NO_HZ_FULL
rcu: Make large and small sysidle systems use same state machine
rcutorture: Add forward-progress checking for writer
torture: Remove obsolete builddir options
torture: Add batch headers "--dryrun sched"
torture: Make parse-rcutorture.sh less RCU-specific
torture: Rename RCU_INITRD to TORTURE_INITRD
torture: Intensify locking test
torture: Allow variations of "defconfig" to be specified
torture: Rename RCU_KMAKE_ARG to TORTURE_KMAKE_ARG
torture: Rename RCU_BOOTARGS to TORTURE_BOOTARGS
torture: Rename RCU_BUILDONLY to TORTURE_BUILDONLY
torture: Rename RCU_QEMU_INTERACTIVE to TORTURE_QEMU_INTERACTIVE
torture: Rename RCU_QEMU_MAC to TORTURE_QEMU_MAC
torture: Rename RCU_QEMU_ARG to TORTURE_QEMU_ARG
torture: Rename RCU_QEMU_CMD to TORTURE_QEMU_CMD
torture: Make config-fragment filtering RCU-independent
torture: Make "--dryrun script" output self-sufficient
torture: Make "--dryrun script" use same environment as normal run
rcutorture: Print negatives for SRCU counter wraparound
torture: Include "Stopping" string to torture_kthread_stopping()
torture: Report diagnostics from qemu
torture: Increase stutter-end intensity
torture: Permit multi-word qemu and boot arguments
torture: Choose bzImage location based on architecture
torture: Add tracing-enabled variant of TREE02
torture: Dump ftrace buffer when the RCU grace period stalls
rcutorture: Export RCU grace-period kthread wait state to rcutorture
percpu: Fix raw_cpu_inc_return()
sched,rcu: Make cond_resched() report RCU quiescent states
rcutorture: Make rcu_torture_reader() use cond_resched()
torture: Better summary diagnostics for build failures
rcutorture: Check for rcu_torture_fqs creation errors
torture: Use elapsed time to detect hangs
rcutorture: Test RCU-sched primitives in TREE_PREEMPT_RCU kernels
rcutorture: Add tests for get_state_synchronize_rcu()
rcutorture: Explicitly test synchronous grace-period primitives
rcutorture: Note diffs from git commits
rcutorture: Run rcu_torture_writer at normal priority
locktorture: Remove reference to nonexistent Kconfig parameter
torture: Check for multiple concurrent torture tests
Pranith Kumar (3):
rcu: Remove duplicate resched_cpu() declaration
torture: Remove __init from torture_init_begin/end
torture: Remove unused definition
Rashika Kheria (1):
rcutorture: Mark function as static in kernel/rcu/torture.c
Rik van Riel (1):
rcu: Provide API to suppress stall warnings while sysrc runs
Thomas Gleixner (1):
rcutorture: Add missing destroy_timer_on_stack()
Uma Sharma (1):
rcu: Variable name changed in tree_plugin.h and used in tree.c
Documentation/RCU/00-INDEX | 2 +
Documentation/RCU/checklist.txt | 12 +-
Documentation/RCU/rcu_dereference.txt | 371 +++++++++++++++++++++
Documentation/RCU/stallwarn.txt | 2 +-
Documentation/RCU/whatisRCU.txt | 55 ++-
include/linux/percpu.h | 2 +-
include/linux/rcupdate.h | 72 +++-
include/linux/rcutiny.h | 4 +
include/linux/rcutree.h | 1 +
include/linux/torture.h | 8 +-
kernel/locking/locktorture.c | 10 +-
kernel/rcu/rcutorture.c | 217 +++++++++---
kernel/rcu/tiny_plugin.h | 8 +-
kernel/rcu/tree.c | 309 ++++++++++++-----
kernel/rcu/tree.h | 11 +-
kernel/rcu/tree_plugin.h | 136 ++------
kernel/rcu/update.c | 30 ++
kernel/sched/core.c | 7 +-
kernel/softirq.c | 4 +-
kernel/torture.c | 40 ++-
.../testing/selftests/rcutorture/bin/configinit.sh | 2 +-
.../testing/selftests/rcutorture/bin/functions.sh | 48 ++-
.../testing/selftests/rcutorture/bin/kvm-build.sh | 6 +-
.../selftests/rcutorture/bin/kvm-recheck-lock.sh | 2 +-
.../selftests/rcutorture/bin/kvm-recheck-rcu.sh | 2 +-
.../selftests/rcutorture/bin/kvm-recheck.sh | 24 +-
.../selftests/rcutorture/bin/kvm-test-1-run.sh | 47 ++-
tools/testing/selftests/rcutorture/bin/kvm.sh | 142 ++++----
.../bin/{parse-rcutorture.sh => parse-torture.sh} | 22 +-
.../selftests/rcutorture/configs/rcu/TREE02-T | 25 ++
.../selftests/rcutorture/configs/rcu/TREE08.boot | 1 +
31 files changed, 1210 insertions(+), 412 deletions(-)
create mode 100644 Documentation/RCU/rcu_dereference.txt
rename tools/testing/selftests/rcutorture/bin/{parse-rcutorture.sh => parse-torture.sh} (79%)
create mode 100644 tools/testing/selftests/rcutorture/configs/rcu/TREE02-T
create mode 100644 tools/testing/selftests/rcutorture/configs/rcu/TREE08.boot
diff --git a/Documentation/RCU/00-INDEX b/Documentation/RCU/00-INDEX
index fa57139..f773a26 100644
--- a/Documentation/RCU/00-INDEX
+++ b/Documentation/RCU/00-INDEX
@@ -12,6 +12,8 @@ lockdep-splat.txt
- RCU Lockdep splats explained.
NMI-RCU.txt
- Using RCU to Protect Dynamic NMI Handlers
+rcu_dereference.txt
+ - Proper care and feeding of return values from rcu_dereference()
rcubarrier.txt
- RCU and Unloadable Modules
rculist_nulls.txt
diff --git a/Documentation/RCU/checklist.txt b/Documentation/RCU/checklist.txt
index 9d10d1d..8779471 100644
--- a/Documentation/RCU/checklist.txt
+++ b/Documentation/RCU/checklist.txt
@@ -114,12 +114,16 @@ over a rather long period of time, but improvements are always welcome!
http://www.openvms.compaq.com/wizard/wiz_2637.html
The rcu_dereference() primitive is also an excellent
- documentation aid, letting the person reading the code
- know exactly which pointers are protected by RCU.
+ documentation aid, letting the person reading the
+ code know exactly which pointers are protected by RCU.
Please note that compilers can also reorder code, and
they are becoming increasingly aggressive about doing
- just that. The rcu_dereference() primitive therefore
- also prevents destructive compiler optimizations.
+ just that. The rcu_dereference() primitive therefore also
+ prevents destructive compiler optimizations. However,
+ with a bit of devious creativity, it is possible to
+ mishandle the return value from rcu_dereference().
+ Please see rcu_dereference.txt in this directory for
+ more information.
The rcu_dereference() primitive is used by the
various "_rcu()" list-traversal primitives, such
diff --git a/Documentation/RCU/rcu_dereference.txt b/Documentation/RCU/rcu_dereference.txt
new file mode 100644
index 0000000..ceb05da
--- /dev/null
+++ b/Documentation/RCU/rcu_dereference.txt
@@ -0,0 +1,371 @@
+PROPER CARE AND FEEDING OF RETURN VALUES FROM rcu_dereference()
+
+Most of the time, you can use values from rcu_dereference() or one of
+the similar primitives without worries. Dereferencing (prefix "*"),
+field selection ("->"), assignment ("="), address-of ("&"), addition and
+subtraction of constants, and casts all work quite naturally and safely.
+
+It is nevertheless possible to get into trouble with other operations.
+Follow these rules to keep your RCU code working properly:
+
+o You must use one of the rcu_dereference() family of primitives
+ to load an RCU-protected pointer, otherwise CONFIG_PROVE_RCU
+ will complain. Worse yet, your code can see random memory-corruption
+ bugs due to games that compilers and DEC Alpha can play.
+ Without one of the rcu_dereference() primitives, compilers
+ can reload the value, and won't your code have fun with two
+ different values for a single pointer! Without rcu_dereference(),
+ DEC Alpha can load a pointer, dereference that pointer, and
+ return data preceding initialization that preceded the store of
+ the pointer.
+
+ In addition, the volatile cast in rcu_dereference() prevents the
+ compiler from deducing the resulting pointer value. Please see
+ the section entitled "EXAMPLE WHERE THE COMPILER KNOWS TOO MUCH"
+ for an example where the compiler can in fact deduce the exact
+ value of the pointer, and thus cause misordering.
+
+o Do not use single-element RCU-protected arrays. The compiler
+ is within its right to assume that the value of an index into
+ such an array must necessarily evaluate to zero. The compiler
+ could then substitute the constant zero for the computation, so
+ that the array index no longer depended on the value returned
+ by rcu_dereference(). If the array index no longer depends
+ on rcu_dereference(), then both the compiler and the CPU
+ are within their rights to order the array access before the
+ rcu_dereference(), which can cause the array access to return
+ garbage.
+
+o Avoid cancellation when using the "+" and "-" infix arithmetic
+ operators. For example, for a given variable "x", avoid
+ "(x-x)". There are similar arithmetic pitfalls from other
+ arithmetic operatiors, such as "(x*0)", "(x/(x+1))" or "(x%1)".
+ The compiler is within its rights to substitute zero for all of
+ these expressions, so that subsequent accesses no longer depend
+ on the rcu_dereference(), again possibly resulting in bugs due
+ to misordering.
+
+ Of course, if "p" is a pointer from rcu_dereference(), and "a"
+ and "b" are integers that happen to be equal, the expression
+ "p+a-b" is safe because its value still necessarily depends on
+ the rcu_dereference(), thus maintaining proper ordering.
+
+o Avoid all-zero operands to the bitwise "&" operator, and
+ similarly avoid all-ones operands to the bitwise "|" operator.
+ If the compiler is able to deduce the value of such operands,
+ it is within its rights to substitute the corresponding constant
+ for the bitwise operation. Once again, this causes subsequent
+ accesses to no longer depend on the rcu_dereference(), causing
+ bugs due to misordering.
+
+ Please note that single-bit operands to bitwise "&" can also
+ be dangerous. At this point, the compiler knows that the
+ resulting value can only take on one of two possible values.
+ Therefore, a very small amount of additional information will
+ allow the compiler to deduce the exact value, which again can
+ result in misordering.
+
+o If you are using RCU to protect JITed functions, so that the
+ "()" function-invocation operator is applied to a value obtained
+ (directly or indirectly) from rcu_dereference(), you may need to
+ interact directly with the hardware to flush instruction caches.
+ This issue arises on some systems when a newly JITed function is
+ using the same memory that was used by an earlier JITed function.
+
+o Do not use the results from the boolean "&&" and "||" when
+ dereferencing. For example, the following (rather improbable)
+ code is buggy:
+
+ int a[2];
+ int index;
+ int force_zero_index = 1;
+
+ ...
+
+ r1 = rcu_dereference(i1)
+ r2 = a[r1 && force_zero_index]; /* BUGGY!!! */
+
+ The reason this is buggy is that "&&" and "||" are often compiled
+ using branches. While weak-memory machines such as ARM or PowerPC
+ do order stores after such branches, they can speculate loads,
+ which can result in misordering bugs.
+
+o Do not use the results from relational operators ("==", "!=",
+ ">", ">=", "<", or "<=") when dereferencing. For example,
+ the following (quite strange) code is buggy:
+
+ int a[2];
+ int index;
+ int flip_index = 0;
+
+ ...
+
+ r1 = rcu_dereference(i1)
+ r2 = a[r1 != flip_index]; /* BUGGY!!! */
+
+ As before, the reason this is buggy is that relational operators
+ are often compiled using branches. And as before, although
+ weak-memory machines such as ARM or PowerPC do order stores
+ after such branches, but can speculate loads, which can again
+ result in misordering bugs.
+
+o Be very careful about comparing pointers obtained from
+ rcu_dereference() against non-NULL values. As Linus Torvalds
+ explained, if the two pointers are equal, the compiler could
+ substitute the pointer you are comparing against for the pointer
+ obtained from rcu_dereference(). For example:
+
+ p = rcu_dereference(gp);
+ if (p == &default_struct)
+ do_default(p->a);
+
+ Because the compiler now knows that the value of "p" is exactly
+ the address of the variable "default_struct", it is free to
+ transform this code into the following:
+
+ p = rcu_dereference(gp);
+ if (p == &default_struct)
+ do_default(default_struct.a);
+
+ On ARM and Power hardware, the load from "default_struct.a"
+ can now be speculated, such that it might happen before the
+ rcu_dereference(). This could result in bugs due to misordering.
+
+ However, comparisons are OK in the following cases:
+
+ o The comparison was against the NULL pointer. If the
+ compiler knows that the pointer is NULL, you had better
+ not be dereferencing it anyway. If the comparison is
+ non-equal, the compiler is none the wiser. Therefore,
+ it is safe to compare pointers from rcu_dereference()
+ against NULL pointers.
+
+ o The pointer is never dereferenced after being compared.
+ Since there are no subsequent dereferences, the compiler
+ cannot use anything it learned from the comparison
+ to reorder the non-existent subsequent dereferences.
+ This sort of comparison occurs frequently when scanning
+ RCU-protected circular linked lists.
+
+ o The comparison is against a pointer that references memory
+ that was initialized "a long time ago." The reason
+ this is safe is that even if misordering occurs, the
+ misordering will not affect the accesses that follow
+ the comparison. So exactly how long ago is "a long
+ time ago"? Here are some possibilities:
+
+ o Compile time.
+
+ o Boot time.
+
+ o Module-init time for module code.
+
+ o Prior to kthread creation for kthread code.
+
+ o During some prior acquisition of the lock that
+ we now hold.
+
+ o Before mod_timer() time for a timer handler.
+
+ There are many other possibilities involving the Linux
+ kernel's wide array of primitives that cause code to
+ be invoked at a later time.
+
+ o The pointer being compared against also came from
+ rcu_dereference(). In this case, both pointers depend
+ on one rcu_dereference() or another, so you get proper
+ ordering either way.
+
+ That said, this situation can make certain RCU usage
+ bugs more likely to happen. Which can be a good thing,
+ at least if they happen during testing. An example
+ of such an RCU usage bug is shown in the section titled
+ "EXAMPLE OF AMPLIFIED RCU-USAGE BUG".
+
+ o All of the accesses following the comparison are stores,
+ so that a control dependency preserves the needed ordering.
+ That said, it is easy to get control dependencies wrong.
+ Please see the "CONTROL DEPENDENCIES" section of
+ Documentation/memory-barriers.txt for more details.
+
+ o The pointers are not equal -and- the compiler does
+ not have enough information to deduce the value of the
+ pointer. Note that the volatile cast in rcu_dereference()
+ will normally prevent the compiler from knowing too much.
+
+o Disable any value-speculation optimizations that your compiler
+ might provide, especially if you are making use of feedback-based
+ optimizations that take data collected from prior runs. Such
+ value-speculation optimizations reorder operations by design.
+
+ There is one exception to this rule: Value-speculation
+ optimizations that leverage the branch-prediction hardware are
+ safe on strongly ordered systems (such as x86), but not on weakly
+ ordered systems (such as ARM or Power). Choose your compiler
+ command-line options wisely!
+
+
+EXAMPLE OF AMPLIFIED RCU-USAGE BUG
+
+Because updaters can run concurrently with RCU readers, RCU readers can
+see stale and/or inconsistent values. If RCU readers need fresh or
+consistent values, which they sometimes do, they need to take proper
+precautions. To see this, consider the following code fragment:
+
+ struct foo {
+ int a;
+ int b;
+ int c;
+ };
+ struct foo *gp1;
+ struct foo *gp2;
+
+ void updater(void)
+ {
+ struct foo *p;
+
+ p = kmalloc(...);
+ if (p == NULL)
+ deal_with_it();
+ p->a = 42; /* Each field in its own cache line. */
+ p->b = 43;
+ p->c = 44;
+ rcu_assign_pointer(gp1, p);
+ p->b = 143;
+ p->c = 144;
+ rcu_assign_pointer(gp2, p);
+ }
+
+ void reader(void)
+ {
+ struct foo *p;
+ struct foo *q;
+ int r1, r2;
+
+ p = rcu_dereference(gp2);
+ if (p == NULL)
+ return;
+ r1 = p->b; /* Guaranteed to get 143. */
+ q = rcu_dereference(gp1); /* Guaranteed non-NULL. */
+ if (p == q) {
+ /* The compiler decides that q->c is same as p->c. */
+ r2 = p->c; /* Could get 44 on weakly order system. */
+ }
+ do_something_with(r1, r2);
+ }
+
+You might be surprised that the outcome (r1 == 143 && r2 == 44) is possible,
+but you should not be. After all, the updater might have been invoked
+a second time between the time reader() loaded into "r1" and the time
+that it loaded into "r2". The fact that this same result can occur due
+to some reordering from the compiler and CPUs is beside the point.
+
+But suppose that the reader needs a consistent view?
+
+Then one approach is to use locking, for example, as follows:
+
+ struct foo {
+ int a;
+ int b;
+ int c;
+ spinlock_t lock;
+ };
+ struct foo *gp1;
+ struct foo *gp2;
+
+ void updater(void)
+ {
+ struct foo *p;
+
+ p = kmalloc(...);
+ if (p == NULL)
+ deal_with_it();
+ spin_lock(&p->lock);
+ p->a = 42; /* Each field in its own cache line. */
+ p->b = 43;
+ p->c = 44;
+ spin_unlock(&p->lock);
+ rcu_assign_pointer(gp1, p);
+ spin_lock(&p->lock);
+ p->b = 143;
+ p->c = 144;
+ spin_unlock(&p->lock);
+ rcu_assign_pointer(gp2, p);
+ }
+
+ void reader(void)
+ {
+ struct foo *p;
+ struct foo *q;
+ int r1, r2;
+
+ p = rcu_dereference(gp2);
+ if (p == NULL)
+ return;
+ spin_lock(&p->lock);
+ r1 = p->b; /* Guaranteed to get 143. */
+ q = rcu_dereference(gp1); /* Guaranteed non-NULL. */
+ if (p == q) {
+ /* The compiler decides that q->c is same as p->c. */
+ r2 = p->c; /* Locking guarantees r2 == 144. */
+ }
+ spin_unlock(&p->lock);
+ do_something_with(r1, r2);
+ }
+
+As always, use the right tool for the job!
+
+
+EXAMPLE WHERE THE COMPILER KNOWS TOO MUCH
+
+If a pointer obtained from rcu_dereference() compares not-equal to some
+other pointer, the compiler normally has no clue what the value of the
+first pointer might be. This lack of knowledge prevents the compiler
+from carrying out optimizations that otherwise might destroy the ordering
+guarantees that RCU depends on. And the volatile cast in rcu_dereference()
+should prevent the compiler from guessing the value.
+
+But without rcu_dereference(), the compiler knows more than you might
+expect. Consider the following code fragment:
+
+ struct foo {
+ int a;
+ int b;
+ };
+ static struct foo variable1;
+ static struct foo variable2;
+ static struct foo *gp = &variable1;
+
+ void updater(void)
+ {
+ initialize_foo(&variable2);
+ rcu_assign_pointer(gp, &variable2);
+ /*
+ * The above is the only store to gp in this translation unit,
+ * and the address of gp is not exported in any way.
+ */
+ }
+
+ int reader(void)
+ {
+ struct foo *p;
+
+ p = gp;
+ barrier();
+ if (p == &variable1)
+ return p->a; /* Must be variable1.a. */
+ else
+ return p->b; /* Must be variable2.b. */
+ }
+
+Because the compiler can see all stores to "gp", it knows that the only
+possible values of "gp" are "variable1" on the one hand and "variable2"
+on the other. The comparison in reader() therefore tells the compiler
+the exact value of "p" even in the not-equals case. This allows the
+compiler to make the return values independent of the load from "gp",
+in turn destroying the ordering between this load and the loads of the
+return values. This can result in "p->b" returning pre-initialization
+garbage values.
+
+In short, rcu_dereference() is -not- optional when you are going to
+dereference the resulting pointer.
diff --git a/Documentation/RCU/stallwarn.txt b/Documentation/RCU/stallwarn.txt
index 6f3a005..68fe3ad 100644
--- a/Documentation/RCU/stallwarn.txt
+++ b/Documentation/RCU/stallwarn.txt
@@ -24,7 +24,7 @@ CONFIG_RCU_CPU_STALL_TIMEOUT
timing of the next warning for the current stall.
Stall-warning messages may be enabled and disabled completely via
- /sys/module/rcutree/parameters/rcu_cpu_stall_suppress.
+ /sys/module/rcupdate/parameters/rcu_cpu_stall_suppress.
CONFIG_RCU_CPU_STALL_VERBOSE
diff --git a/Documentation/RCU/whatisRCU.txt b/Documentation/RCU/whatisRCU.txt
index 0f0fb7c..49b8551 100644
--- a/Documentation/RCU/whatisRCU.txt
+++ b/Documentation/RCU/whatisRCU.txt
@@ -326,11 +326,11 @@ used as follows:
a. synchronize_rcu() rcu_read_lock() / rcu_read_unlock()
call_rcu() rcu_dereference()
-b. call_rcu_bh() rcu_read_lock_bh() / rcu_read_unlock_bh()
- rcu_dereference_bh()
+b. synchronize_rcu_bh() rcu_read_lock_bh() / rcu_read_unlock_bh()
+ call_rcu_bh() rcu_dereference_bh()
c. synchronize_sched() rcu_read_lock_sched() / rcu_read_unlock_sched()
- preempt_disable() / preempt_enable()
+ call_rcu_sched() preempt_disable() / preempt_enable()
local_irq_save() / local_irq_restore()
hardirq enter / hardirq exit
NMI enter / NMI exit
@@ -794,10 +794,22 @@ in docbook. Here is the list, by category.
RCU list traversal:
+ list_entry_rcu
+ list_first_entry_rcu
+ list_next_rcu
list_for_each_entry_rcu
+ list_for_each_entry_continue_rcu
+ hlist_first_rcu
+ hlist_next_rcu
+ hlist_pprev_rcu
hlist_for_each_entry_rcu
+ hlist_for_each_entry_rcu_bh
+ hlist_for_each_entry_continue_rcu
+ hlist_for_each_entry_continue_rcu_bh
+ hlist_nulls_first_rcu
hlist_nulls_for_each_entry_rcu
- list_for_each_entry_continue_rcu
+ hlist_bl_first_rcu
+ hlist_bl_for_each_entry_rcu
RCU pointer/list update:
@@ -806,28 +818,38 @@ RCU pointer/list update:
list_add_tail_rcu
list_del_rcu
list_replace_rcu
- hlist_del_rcu
hlist_add_after_rcu
hlist_add_before_rcu
hlist_add_head_rcu
+ hlist_del_rcu
+ hlist_del_init_rcu
hlist_replace_rcu
list_splice_init_rcu()
+ hlist_nulls_del_init_rcu
+ hlist_nulls_del_rcu
+ hlist_nulls_add_head_rcu
+ hlist_bl_add_head_rcu
+ hlist_bl_del_init_rcu
+ hlist_bl_del_rcu
+ hlist_bl_set_first_rcu
RCU: Critical sections Grace period Barrier
rcu_read_lock synchronize_net rcu_barrier
rcu_read_unlock synchronize_rcu
rcu_dereference synchronize_rcu_expedited
- call_rcu
- kfree_rcu
-
+ rcu_read_lock_held call_rcu
+ rcu_dereference_check kfree_rcu
+ rcu_dereference_protected
bh: Critical sections Grace period Barrier
rcu_read_lock_bh call_rcu_bh rcu_barrier_bh
rcu_read_unlock_bh synchronize_rcu_bh
rcu_dereference_bh synchronize_rcu_bh_expedited
-
+ rcu_dereference_bh_check
+ rcu_dereference_bh_protected
+ rcu_read_lock_bh_held
sched: Critical sections Grace period Barrier
@@ -835,7 +857,12 @@ sched: Critical sections Grace period Barrier
rcu_read_unlock_sched call_rcu_sched
[preempt_disable] synchronize_sched_expedited
[and friends]
+ rcu_read_lock_sched_notrace
+ rcu_read_unlock_sched_notrace
rcu_dereference_sched
+ rcu_dereference_sched_check
+ rcu_dereference_sched_protected
+ rcu_read_lock_sched_held
SRCU: Critical sections Grace period Barrier
@@ -843,6 +870,8 @@ SRCU: Critical sections Grace period Barrier
srcu_read_lock synchronize_srcu srcu_barrier
srcu_read_unlock call_srcu
srcu_dereference synchronize_srcu_expedited
+ srcu_dereference_check
+ srcu_read_lock_held
SRCU: Initialization/cleanup
init_srcu_struct
@@ -850,9 +879,13 @@ SRCU: Initialization/cleanup
All: lockdep-checked RCU-protected pointer access
- rcu_dereference_check
- rcu_dereference_protected
+ rcu_access_index
rcu_access_pointer
+ rcu_dereference_index_check
+ rcu_dereference_raw
+ rcu_lockdep_assert
+ rcu_sleep_check
+ RCU_NONIDLE
See the comment headers in the source code (or the docbook generated
from them) for more information.
diff --git a/include/linux/percpu.h b/include/linux/percpu.h
index e7a0b95..495c654 100644
--- a/include/linux/percpu.h
+++ b/include/linux/percpu.h
@@ -639,7 +639,7 @@ do { \
# define raw_cpu_add_return_8(pcp, val) raw_cpu_generic_add_return(pcp, val)
# endif
# define raw_cpu_add_return(pcp, val) \
- __pcpu_size_call_return2(raw_add_return_, pcp, val)
+ __pcpu_size_call_return2(raw_cpu_add_return_, pcp, val)
#endif
#define raw_cpu_sub_return(pcp, val) raw_cpu_add_return(pcp, -(typeof(pcp))(val))
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index 00a7fd6..5a75d19 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -44,6 +44,7 @@
#include <linux/debugobjects.h>
#include <linux/bug.h>
#include <linux/compiler.h>
+#include <linux/percpu.h>
#include <asm/barrier.h>
extern int rcu_expedited; /* for sysctl */
@@ -51,7 +52,17 @@ extern int rcu_expedited; /* for sysctl */
extern int rcutorture_runnable; /* for sysctl */
#endif /* #ifdef CONFIG_RCU_TORTURE_TEST */
+enum rcutorture_type {
+ RCU_FLAVOR,
+ RCU_BH_FLAVOR,
+ RCU_SCHED_FLAVOR,
+ SRCU_FLAVOR,
+ INVALID_RCU_FLAVOR
+};
+
#if defined(CONFIG_TREE_RCU) || defined(CONFIG_TREE_PREEMPT_RCU)
+void rcutorture_get_gp_data(enum rcutorture_type test_type, int *flags,
+ unsigned long *gpnum, unsigned long *completed);
void rcutorture_record_test_transition(void);
void rcutorture_record_progress(unsigned long vernum);
void do_trace_rcu_torture_read(const char *rcutorturename,
@@ -60,6 +71,15 @@ void do_trace_rcu_torture_read(const char *rcutorturename,
unsigned long c_old,
unsigned long c);
#else
+static inline void rcutorture_get_gp_data(enum rcutorture_type test_type,
+ int *flags,
+ unsigned long *gpnum,
+ unsigned long *completed)
+{
+ *flags = 0;
+ *gpnum = 0;
+ *completed = 0;
+}
static inline void rcutorture_record_test_transition(void)
{
}
@@ -228,6 +248,18 @@ void rcu_idle_exit(void);
void rcu_irq_enter(void);
void rcu_irq_exit(void);
+#ifdef CONFIG_RCU_STALL_COMMON
+void rcu_sysrq_start(void);
+void rcu_sysrq_end(void);
+#else /* #ifdef CONFIG_RCU_STALL_COMMON */
+static inline void rcu_sysrq_start(void)
+{
+}
+static inline void rcu_sysrq_end(void)
+{
+}
+#endif /* #else #ifdef CONFIG_RCU_STALL_COMMON */
+
#ifdef CONFIG_RCU_USER_QS
void rcu_user_enter(void);
void rcu_user_exit(void);
@@ -268,6 +300,41 @@ bool __rcu_is_watching(void);
#endif /* #if defined(CONFIG_DEBUG_LOCK_ALLOC) || defined(CONFIG_RCU_TRACE) || defined(CONFIG_SMP) */
/*
+ * Hooks for cond_resched() and friends to avoid RCU CPU stall warnings.
+ */
+
+#define RCU_COND_RESCHED_LIM 256 /* ms vs. 100s of ms. */
+DECLARE_PER_CPU(int, rcu_cond_resched_count);
+void rcu_resched(void);
+
+/*
+ * Is it time to report RCU quiescent states?
+ *
+ * Note unsynchronized access to rcu_cond_resched_count. Yes, we might
+ * increment some random CPU's count, and possibly also load the result from
+ * yet another CPU's count. We might even clobber some other CPU's attempt
+ * to zero its counter. This is all OK because the goal is not precision,
+ * but rather reasonable amortization of rcu_note_context_switch() overhead
+ * and extremely high probability of avoiding RCU CPU stall warnings.
+ * Note that this function has to be preempted in just the wrong place,
+ * many thousands of times in a row, for anything bad to happen.
+ */
+static inline bool rcu_should_resched(void)
+{
+ return raw_cpu_inc_return(rcu_cond_resched_count) >=
+ RCU_COND_RESCHED_LIM;
+}
+
+/*
+ * Report quiscent states to RCU if it is time to do so.
+ */
+static inline void rcu_cond_resched(void)
+{
+ if (unlikely(rcu_should_resched()))
+ rcu_resched();
+}
+
+/*
* Infrastructure to implement the synchronize_() primitives in
* TREE_RCU and rcu_barrier_() primitives in TINY_RCU.
*/
@@ -328,7 +395,7 @@ extern struct lockdep_map rcu_lock_map;
extern struct lockdep_map rcu_bh_lock_map;
extern struct lockdep_map rcu_sched_lock_map;
extern struct lockdep_map rcu_callback_map;
-extern int debug_lockdep_rcu_enabled(void);
+int debug_lockdep_rcu_enabled(void);
/**
* rcu_read_lock_held() - might we be in RCU read-side critical section?
@@ -949,6 +1016,9 @@ static inline notrace void rcu_read_unlock_sched_notrace(void)
* pointers, but you must use rcu_assign_pointer() to initialize the
* external-to-structure pointer -after- you have completely initialized
* the reader-accessible portions of the linked structure.
+ *
+ * Note that unlike rcu_assign_pointer(), RCU_INIT_POINTER() provides no
+ * ordering guarantees for either the CPU or the compiler.
*/
#define RCU_INIT_POINTER(p, v) \
do { \
diff --git a/include/linux/rcutiny.h b/include/linux/rcutiny.h
index 425c659..d40a6a4 100644
--- a/include/linux/rcutiny.h
+++ b/include/linux/rcutiny.h
@@ -119,6 +119,10 @@ static inline void rcu_sched_force_quiescent_state(void)
{
}
+static inline void show_rcu_gp_kthreads(void)
+{
+}
+
static inline void rcu_cpu_stall_reset(void)
{
}
diff --git a/include/linux/rcutree.h b/include/linux/rcutree.h
index a59ca05..3e2f5d4 100644
--- a/include/linux/rcutree.h
+++ b/include/linux/rcutree.h
@@ -84,6 +84,7 @@ extern unsigned long rcutorture_vernum;
long rcu_batches_completed(void);
long rcu_batches_completed_bh(void);
long rcu_batches_completed_sched(void);
+void show_rcu_gp_kthreads(void);
void rcu_force_quiescent_state(void);
void rcu_bh_force_quiescent_state(void);
diff --git a/include/linux/torture.h b/include/linux/torture.h
index b2e2b46..5ca58fc 100644
--- a/include/linux/torture.h
+++ b/include/linux/torture.h
@@ -49,12 +49,6 @@
#define VERBOSE_TOROUT_ERRSTRING(s) \
do { if (verbose) pr_alert("%s" TORTURE_FLAG "!!! %s\n", torture_type, s); } while (0)
-/* Definitions for a non-string torture-test module parameter. */
-#define torture_parm(type, name, init, msg) \
- static type name = init; \
- module_param(name, type, 0444); \
- MODULE_PARM_DESC(name, msg);
-
/* Definitions for online/offline exerciser. */
int torture_onoff_init(long ooholdoff, long oointerval);
char *torture_onoff_stats(char *page);
@@ -81,7 +75,7 @@ void stutter_wait(const char *title);
int torture_stutter_init(int s);
/* Initialization and cleanup. */
-void torture_init_begin(char *ttype, bool v, int *runnable);
+bool torture_init_begin(char *ttype, bool v, int *runnable);
void torture_init_end(void);
bool torture_cleanup(void);
bool torture_must_stop(void);
diff --git a/kernel/locking/locktorture.c b/kernel/locking/locktorture.c
index f26b1a1..dbafeac 100644
--- a/kernel/locking/locktorture.c
+++ b/kernel/locking/locktorture.c
@@ -82,14 +82,14 @@ struct lock_writer_stress_stats {
};
static struct lock_writer_stress_stats *lwsa;
-#if defined(MODULE) || defined(CONFIG_LOCK_TORTURE_TEST_RUNNABLE)
+#if defined(MODULE)
#define LOCKTORTURE_RUNNABLE_INIT 1
#else
#define LOCKTORTURE_RUNNABLE_INIT 0
#endif
int locktorture_runnable = LOCKTORTURE_RUNNABLE_INIT;
module_param(locktorture_runnable, int, 0444);
-MODULE_PARM_DESC(locktorture_runnable, "Start locktorture at boot");
+MODULE_PARM_DESC(locktorture_runnable, "Start locktorture at module init");
/* Forward reference. */
static void lock_torture_cleanup(void);
@@ -219,7 +219,8 @@ static int lock_torture_writer(void *arg)
set_user_nice(current, 19);
do {
- schedule_timeout_uninterruptible(1);
+ if ((torture_random(&rand) & 0xfffff) == 0)
+ schedule_timeout_uninterruptible(1);
cur_ops->writelock();
if (WARN_ON_ONCE(lock_is_write_held))
lwsp->n_write_lock_fail++;
@@ -354,7 +355,8 @@ static int __init lock_torture_init(void)
&lock_busted_ops, &spin_lock_ops, &spin_lock_irq_ops,
};
- torture_init_begin(torture_type, verbose, &locktorture_runnable);
+ if (!torture_init_begin(torture_type, verbose, &locktorture_runnable))
+ return -EBUSY;
/* Process args and tell the world that the torturer is on the job. */
for (i = 0; i < ARRAY_SIZE(torture_ops); i++) {
diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
index bd30bc6..7fa34f8 100644
--- a/kernel/rcu/rcutorture.c
+++ b/kernel/rcu/rcutorture.c
@@ -58,9 +58,11 @@ torture_param(int, fqs_duration, 0,
"Duration of fqs bursts (us), 0 to disable");
torture_param(int, fqs_holdoff, 0, "Holdoff time within fqs bursts (us)");
torture_param(int, fqs_stutter, 3, "Wait time between fqs bursts (s)");
+torture_param(bool, gp_cond, false, "Use conditional/async GP wait primitives");
torture_param(bool, gp_exp, false, "Use expedited GP wait primitives");
torture_param(bool, gp_normal, false,
"Use normal (non-expedited) GP wait primitives");
+torture_param(bool, gp_sync, false, "Use synchronous GP wait primitives");
torture_param(int, irqreader, 1, "Allow RCU readers from irq handlers");
torture_param(int, n_barrier_cbs, 0,
"# of callbacks/kthreads for barrier testing");
@@ -138,6 +140,18 @@ static long n_barrier_attempts;
static long n_barrier_successes;
static struct list_head rcu_torture_removed;
+static int rcu_torture_writer_state;
+#define RTWS_FIXED_DELAY 0
+#define RTWS_DELAY 1
+#define RTWS_REPLACE 2
+#define RTWS_DEF_FREE 3
+#define RTWS_EXP_SYNC 4
+#define RTWS_COND_GET 5
+#define RTWS_COND_SYNC 6
+#define RTWS_SYNC 7
+#define RTWS_STUTTER 8
+#define RTWS_STOPPING 9
+
#if defined(MODULE) || defined(CONFIG_RCU_TORTURE_TEST_RUNNABLE)
#define RCUTORTURE_RUNNABLE_INIT 1
#else
@@ -214,6 +228,7 @@ rcu_torture_free(struct rcu_torture *p)
*/
struct rcu_torture_ops {
+ int ttype;
void (*init)(void);
int (*readlock)(void);
void (*read_delay)(struct torture_random_state *rrsp);
@@ -222,6 +237,8 @@ struct rcu_torture_ops {
void (*deferred_free)(struct rcu_torture *p);
void (*sync)(void);
void (*exp_sync)(void);
+ unsigned long (*get_state)(void);
+ void (*cond_sync)(unsigned long oldstate);
void (*call)(struct rcu_head *head, void (*func)(struct rcu_head *rcu));
void (*cb_barrier)(void);
void (*fqs)(void);
@@ -273,10 +290,48 @@ static int rcu_torture_completed(void)
return rcu_batches_completed();
}
+/*
+ * Update callback in the pipe. This should be invoked after a grace period.
+ */
+static bool
+rcu_torture_pipe_update_one(struct rcu_torture *rp)
+{
+ int i;
+
+ i = rp->rtort_pipe_count;
+ if (i > RCU_TORTURE_PIPE_LEN)
+ i = RCU_TORTURE_PIPE_LEN;
+ atomic_inc(&rcu_torture_wcount[i]);
+ if (++rp->rtort_pipe_count >= RCU_TORTURE_PIPE_LEN) {
+ rp->rtort_mbtest = 0;
+ return true;
+ }
+ return false;
+}
+
+/*
+ * Update all callbacks in the pipe. Suitable for synchronous grace-period
+ * primitives.
+ */
+static void
+rcu_torture_pipe_update(struct rcu_torture *old_rp)
+{
+ struct rcu_torture *rp;
+ struct rcu_torture *rp1;
+
+ if (old_rp)
+ list_add(&old_rp->rtort_free, &rcu_torture_removed);
+ list_for_each_entry_safe(rp, rp1, &rcu_torture_removed, rtort_free) {
+ if (rcu_torture_pipe_update_one(rp)) {
+ list_del(&rp->rtort_free);
+ rcu_torture_free(rp);
+ }
+ }
+}
+
static void
rcu_torture_cb(struct rcu_head *p)
{
- int i;
struct rcu_torture *rp = container_of(p, struct rcu_torture, rtort_rcu);
if (torture_must_stop_irq()) {
@@ -284,16 +339,10 @@ rcu_torture_cb(struct rcu_head *p)
/* The next initialization will pick up the pieces. */
return;
}
- i = rp->rtort_pipe_count;
- if (i > RCU_TORTURE_PIPE_LEN)
- i = RCU_TORTURE_PIPE_LEN;
- atomic_inc(&rcu_torture_wcount[i]);
- if (++rp->rtort_pipe_count >= RCU_TORTURE_PIPE_LEN) {
- rp->rtort_mbtest = 0;
+ if (rcu_torture_pipe_update_one(rp))
rcu_torture_free(rp);
- } else {
+ else
cur_ops->deferred_free(rp);
- }
}
static int rcu_no_completed(void)
@@ -312,6 +361,7 @@ static void rcu_sync_torture_init(void)
}
static struct rcu_torture_ops rcu_ops = {
+ .ttype = RCU_FLAVOR,
.init = rcu_sync_torture_init,
.readlock = rcu_torture_read_lock,
.read_delay = rcu_read_delay,
@@ -320,6 +370,8 @@ static struct rcu_torture_ops rcu_ops = {
.deferred_free = rcu_torture_deferred_free,
.sync = synchronize_rcu,
.exp_sync = synchronize_rcu_expedited,
+ .get_state = get_state_synchronize_rcu,
+ .cond_sync = cond_synchronize_rcu,
.call = call_rcu,
.cb_barrier = rcu_barrier,
.fqs = rcu_force_quiescent_state,
@@ -355,6 +407,7 @@ static void rcu_bh_torture_deferred_free(struct rcu_torture *p)
}
static struct rcu_torture_ops rcu_bh_ops = {
+ .ttype = RCU_BH_FLAVOR,
.init = rcu_sync_torture_init,
.readlock = rcu_bh_torture_read_lock,
.read_delay = rcu_read_delay, /* just reuse rcu's version. */
@@ -397,6 +450,7 @@ call_rcu_busted(struct rcu_head *head, void (*func)(struct rcu_head *rcu))
}
static struct rcu_torture_ops rcu_busted_ops = {
+ .ttype = INVALID_RCU_FLAVOR,
.init = rcu_sync_torture_init,
.readlock = rcu_torture_read_lock,
.read_delay = rcu_read_delay, /* just reuse rcu's version. */
@@ -479,9 +533,11 @@ static void srcu_torture_stats(char *page)
page += sprintf(page, "%s%s per-CPU(idx=%d):",
torture_type, TORTURE_FLAG, idx);
for_each_possible_cpu(cpu) {
- page += sprintf(page, " %d(%lu,%lu)", cpu,
- per_cpu_ptr(srcu_ctl.per_cpu_ref, cpu)->c[!idx],
- per_cpu_ptr(srcu_ctl.per_cpu_ref, cpu)->c[idx]);
+ long c0, c1;
+
+ c0 = (long)per_cpu_ptr(srcu_ctl.per_cpu_ref, cpu)->c[!idx];
+ c1 = (long)per_cpu_ptr(srcu_ctl.per_cpu_ref, cpu)->c[idx];
+ page += sprintf(page, " %d(%ld,%ld)", cpu, c0, c1);
}
sprintf(page, "\n");
}
@@ -492,6 +548,7 @@ static void srcu_torture_synchronize_expedited(void)
}
static struct rcu_torture_ops srcu_ops = {
+ .ttype = SRCU_FLAVOR,
.init = rcu_sync_torture_init,
.readlock = srcu_torture_read_lock,
.read_delay = srcu_read_delay,
@@ -527,6 +584,7 @@ static void rcu_sched_torture_deferred_free(struct rcu_torture *p)
}
static struct rcu_torture_ops sched_ops = {
+ .ttype = RCU_SCHED_FLAVOR,
.init = rcu_sync_torture_init,
.readlock = sched_torture_read_lock,
.read_delay = rcu_read_delay, /* just reuse rcu's version. */
@@ -688,23 +746,59 @@ rcu_torture_fqs(void *arg)
static int
rcu_torture_writer(void *arg)
{
- bool exp;
+ unsigned long gp_snap;
+ bool gp_cond1 = gp_cond, gp_exp1 = gp_exp, gp_normal1 = gp_normal;
+ bool gp_sync1 = gp_sync;
int i;
struct rcu_torture *rp;
- struct rcu_torture *rp1;
struct rcu_torture *old_rp;
static DEFINE_TORTURE_RANDOM(rand);
+ int synctype[] = { RTWS_DEF_FREE, RTWS_EXP_SYNC,
+ RTWS_COND_GET, RTWS_SYNC };
+ int nsynctypes = 0;
VERBOSE_TOROUT_STRING("rcu_torture_writer task started");
- set_user_nice(current, MAX_NICE);
+
+ /* Initialize synctype[] array. If none set, take default. */
+ if (!gp_cond1 && !gp_exp1 && !gp_normal1 && !gp_sync)
+ gp_cond1 = gp_exp1 = gp_normal1 = gp_sync1 = true;
+ if (gp_cond1 && cur_ops->get_state && cur_ops->cond_sync)
+ synctype[nsynctypes++] = RTWS_COND_GET;
+ else if (gp_cond && (!cur_ops->get_state || !cur_ops->cond_sync))
+ pr_alert("rcu_torture_writer: gp_cond without primitives.\n");
+ if (gp_exp1 && cur_ops->exp_sync)
+ synctype[nsynctypes++] = RTWS_EXP_SYNC;
+ else if (gp_exp && !cur_ops->exp_sync)
+ pr_alert("rcu_torture_writer: gp_exp without primitives.\n");
+ if (gp_normal1 && cur_ops->deferred_free)
+ synctype[nsynctypes++] = RTWS_DEF_FREE;
+ else if (gp_normal && !cur_ops->deferred_free)
+ pr_alert("rcu_torture_writer: gp_normal without primitives.\n");
+ if (gp_sync1 && cur_ops->sync)
+ synctype[nsynctypes++] = RTWS_SYNC;
+ else if (gp_sync && !cur_ops->sync)
+ pr_alert("rcu_torture_writer: gp_sync without primitives.\n");
+ if (WARN_ONCE(nsynctypes == 0,
+ "rcu_torture_writer: No update-side primitives.\n")) {
+ /*
+ * No updates primitives, so don't try updating.
+ * The resulting test won't be testing much, hence the
+ * above WARN_ONCE().
+ */
+ rcu_torture_writer_state = RTWS_STOPPING;
+ torture_kthread_stopping("rcu_torture_writer");
+ }
do {
+ rcu_torture_writer_state = RTWS_FIXED_DELAY;
schedule_timeout_uninterruptible(1);
rp = rcu_torture_alloc();
if (rp == NULL)
continue;
rp->rtort_pipe_count = 0;
+ rcu_torture_writer_state = RTWS_DELAY;
udelay(torture_random(&rand) & 0x3ff);
+ rcu_torture_writer_state = RTWS_REPLACE;
old_rp = rcu_dereference_check(rcu_torture_current,
current == writer_task);
rp->rtort_mbtest = 1;
@@ -716,35 +810,42 @@ rcu_torture_writer(void *arg)
i = RCU_TORTURE_PIPE_LEN;
atomic_inc(&rcu_torture_wcount[i]);
old_rp->rtort_pipe_count++;
- if (gp_normal == gp_exp)
- exp = !!(torture_random(&rand) & 0x80);
- else
- exp = gp_exp;
- if (!exp) {
+ switch (synctype[torture_random(&rand) % nsynctypes]) {
+ case RTWS_DEF_FREE:
+ rcu_torture_writer_state = RTWS_DEF_FREE;
cur_ops->deferred_free(old_rp);
- } else {
+ break;
+ case RTWS_EXP_SYNC:
+ rcu_torture_writer_state = RTWS_EXP_SYNC;
cur_ops->exp_sync();
- list_add(&old_rp->rtort_free,
- &rcu_torture_removed);
- list_for_each_entry_safe(rp, rp1,
- &rcu_torture_removed,
- rtort_free) {
- i = rp->rtort_pipe_count;
- if (i > RCU_TORTURE_PIPE_LEN)
- i = RCU_TORTURE_PIPE_LEN;
- atomic_inc(&rcu_torture_wcount[i]);
- if (++rp->rtort_pipe_count >=
- RCU_TORTURE_PIPE_LEN) {
- rp->rtort_mbtest = 0;
- list_del(&rp->rtort_free);
- rcu_torture_free(rp);
- }
- }
+ rcu_torture_pipe_update(old_rp);
+ break;
+ case RTWS_COND_GET:
+ rcu_torture_writer_state = RTWS_COND_GET;
+ gp_snap = cur_ops->get_state();
+ i = torture_random(&rand) % 16;
+ if (i != 0)
+ schedule_timeout_interruptible(i);
+ udelay(torture_random(&rand) % 1000);
+ rcu_torture_writer_state = RTWS_COND_SYNC;
+ cur_ops->cond_sync(gp_snap);
+ rcu_torture_pipe_update(old_rp);
+ break;
+ case RTWS_SYNC:
+ rcu_torture_writer_state = RTWS_SYNC;
+ cur_ops->sync();
+ rcu_torture_pipe_update(old_rp);
+ break;
+ default:
+ WARN_ON_ONCE(1);
+ break;
}
}
rcutorture_record_progress(++rcu_torture_current_version);
+ rcu_torture_writer_state = RTWS_STUTTER;
stutter_wait("rcu_torture_writer");
} while (!torture_must_stop());
+ rcu_torture_writer_state = RTWS_STOPPING;
torture_kthread_stopping("rcu_torture_writer");
return 0;
}
@@ -784,7 +885,7 @@ rcu_torture_fakewriter(void *arg)
return 0;
}
-void rcutorture_trace_dump(void)
+static void rcutorture_trace_dump(void)
{
static atomic_t beenhere = ATOMIC_INIT(0);
@@ -918,11 +1019,13 @@ rcu_torture_reader(void *arg)
__this_cpu_inc(rcu_torture_batch[completed]);
preempt_enable();
cur_ops->readunlock(idx);
- schedule();
+ cond_resched();
stutter_wait("rcu_torture_reader");
} while (!torture_must_stop());
- if (irqreader && cur_ops->irq_capable)
+ if (irqreader && cur_ops->irq_capable) {
del_timer_sync(&t);
+ destroy_timer_on_stack(&t);
+ }
torture_kthread_stopping("rcu_torture_reader");
return 0;
}
@@ -937,6 +1040,7 @@ rcu_torture_printk(char *page)
int i;
long pipesummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
long batchsummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
+ static unsigned long rtcv_snap = ULONG_MAX;
for_each_possible_cpu(cpu) {
for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
@@ -997,6 +1101,22 @@ rcu_torture_printk(char *page)
page += sprintf(page, "\n");
if (cur_ops->stats)
cur_ops->stats(page);
+ if (rtcv_snap == rcu_torture_current_version &&
+ rcu_torture_current != NULL) {
+ int __maybe_unused flags;
+ unsigned long __maybe_unused gpnum;
+ unsigned long __maybe_unused completed;
+
+ rcutorture_get_gp_data(cur_ops->ttype,
+ &flags, &gpnum, &completed);
+ page += sprintf(page,
+ "??? Writer stall state %d g%lu c%lu f%#x\n",
+ rcu_torture_writer_state,
+ gpnum, completed, flags);
+ show_rcu_gp_kthreads();
+ rcutorture_trace_dump();
+ }
+ rtcv_snap = rcu_torture_current_version;
}
/*
@@ -1146,7 +1266,7 @@ static int __init rcu_torture_stall_init(void)
}
/* Callback function for RCU barrier testing. */
-void rcu_torture_barrier_cbf(struct rcu_head *rcu)
+static void rcu_torture_barrier_cbf(struct rcu_head *rcu)
{
atomic_inc(&barrier_cbs_invoked);
}
@@ -1416,7 +1536,8 @@ rcu_torture_init(void)
&rcu_ops, &rcu_bh_ops, &rcu_busted_ops, &srcu_ops, &sched_ops,
};
- torture_init_begin(torture_type, verbose, &rcutorture_runnable);
+ if (!torture_init_begin(torture_type, verbose, &rcutorture_runnable))
+ return -EBUSY;
/* Process args and tell the world that the torturer is on the job. */
for (i = 0; i < ARRAY_SIZE(torture_ops); i++) {
@@ -1441,10 +1562,13 @@ rcu_torture_init(void)
if (cur_ops->init)
cur_ops->init(); /* no "goto unwind" prior to this point!!! */
- if (nreaders >= 0)
+ if (nreaders >= 0) {
nrealreaders = nreaders;
- else
- nrealreaders = 2 * num_online_cpus();
+ } else {
+ nrealreaders = num_online_cpus() - 1;
+ if (nrealreaders <= 0)
+ nrealreaders = 1;
+ }
rcu_torture_print_module_parms(cur_ops, "Start of test");
/* Set up the freelist. */
@@ -1533,7 +1657,8 @@ rcu_torture_init(void)
fqs_duration = 0;
if (fqs_duration) {
/* Create the fqs thread */
- torture_create_kthread(rcu_torture_fqs, NULL, fqs_task);
+ firsterr = torture_create_kthread(rcu_torture_fqs, NULL,
+ fqs_task);
if (firsterr)
goto unwind;
}
diff --git a/kernel/rcu/tiny_plugin.h b/kernel/rcu/tiny_plugin.h
index 4315285..858c565 100644
--- a/kernel/rcu/tiny_plugin.h
+++ b/kernel/rcu/tiny_plugin.h
@@ -144,7 +144,7 @@ static void check_cpu_stall(struct rcu_ctrlblk *rcp)
return;
rcp->ticks_this_gp++;
j = jiffies;
- js = rcp->jiffies_stall;
+ js = ACCESS_ONCE(rcp->jiffies_stall);
if (*rcp->curtail && ULONG_CMP_GE(j, js)) {
pr_err("INFO: %s stall on CPU (%lu ticks this GP) idle=%llx (t=%lu jiffies q=%ld)\n",
rcp->name, rcp->ticks_this_gp, rcu_dynticks_nesting,
@@ -152,17 +152,17 @@ static void check_cpu_stall(struct rcu_ctrlblk *rcp)
dump_stack();
}
if (*rcp->curtail && ULONG_CMP_GE(j, js))
- rcp->jiffies_stall = jiffies +
+ ACCESS_ONCE(rcp->jiffies_stall) = jiffies +
3 * rcu_jiffies_till_stall_check() + 3;
else if (ULONG_CMP_GE(j, js))
- rcp->jiffies_stall = jiffies + rcu_jiffies_till_stall_check();
+ ACCESS_ONCE(rcp->jiffies_stall) = jiffies + rcu_jiffies_till_stall_check();
}
static void reset_cpu_stall_ticks(struct rcu_ctrlblk *rcp)
{
rcp->ticks_this_gp = 0;
rcp->gp_start = jiffies;
- rcp->jiffies_stall = jiffies + rcu_jiffies_till_stall_check();
+ ACCESS_ONCE(rcp->jiffies_stall) = jiffies + rcu_jiffies_till_stall_check();
}
static void check_cpu_stalls(void)
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 0c47e30..3e3f13e 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -101,7 +101,7 @@ DEFINE_PER_CPU(struct rcu_data, sname##_data)
RCU_STATE_INITIALIZER(rcu_sched, 's', call_rcu_sched);
RCU_STATE_INITIALIZER(rcu_bh, 'b', call_rcu_bh);
-static struct rcu_state *rcu_state;
+static struct rcu_state *rcu_state_p;
LIST_HEAD(rcu_struct_flavors);
/* Increase (but not decrease) the CONFIG_RCU_FANOUT_LEAF at boot time. */
@@ -243,7 +243,7 @@ static ulong jiffies_till_next_fqs = ULONG_MAX;
module_param(jiffies_till_first_fqs, ulong, 0644);
module_param(jiffies_till_next_fqs, ulong, 0644);
-static void rcu_start_gp_advanced(struct rcu_state *rsp, struct rcu_node *rnp,
+static bool rcu_start_gp_advanced(struct rcu_state *rsp, struct rcu_node *rnp,
struct rcu_data *rdp);
static void force_qs_rnp(struct rcu_state *rsp,
int (*f)(struct rcu_data *rsp, bool *isidle,
@@ -271,6 +271,15 @@ long rcu_batches_completed_bh(void)
EXPORT_SYMBOL_GPL(rcu_batches_completed_bh);
/*
+ * Force a quiescent state.
+ */
+void rcu_force_quiescent_state(void)
+{
+ force_quiescent_state(rcu_state_p);
+}
+EXPORT_SYMBOL_GPL(rcu_force_quiescent_state);
+
+/*
* Force a quiescent state for RCU BH.
*/
void rcu_bh_force_quiescent_state(void)
@@ -280,6 +289,21 @@ void rcu_bh_force_quiescent_state(void)
EXPORT_SYMBOL_GPL(rcu_bh_force_quiescent_state);
/*
+ * Show the state of the grace-period kthreads.
+ */
+void show_rcu_gp_kthreads(void)
+{
+ struct rcu_state *rsp;
+
+ for_each_rcu_flavor(rsp) {
+ pr_info("%s: wait state: %d ->state: %#lx\n",
+ rsp->name, rsp->gp_state, rsp->gp_kthread->state);
+ /* sched_show_task(rsp->gp_kthread); */
+ }
+}
+EXPORT_SYMBOL_GPL(show_rcu_gp_kthreads);
+
+/*
* Record the number of times rcutorture tests have been initiated and
* terminated. This information allows the debugfs tracing stats to be
* correlated to the rcutorture messages, even when the rcutorture module
@@ -294,6 +318,39 @@ void rcutorture_record_test_transition(void)
EXPORT_SYMBOL_GPL(rcutorture_record_test_transition);
/*
+ * Send along grace-period-related data for rcutorture diagnostics.
+ */
+void rcutorture_get_gp_data(enum rcutorture_type test_type, int *flags,
+ unsigned long *gpnum, unsigned long *completed)
+{
+ struct rcu_state *rsp = NULL;
+
+ switch (test_type) {
+ case RCU_FLAVOR:
+ rsp = rcu_state_p;
+ break;
+ case RCU_BH_FLAVOR:
+ rsp = &rcu_bh_state;
+ break;
+ case RCU_SCHED_FLAVOR:
+ rsp = &rcu_sched_state;
+ break;
+ default:
+ break;
+ }
+ if (rsp != NULL) {
+ *flags = ACCESS_ONCE(rsp->gp_flags);
+ *gpnum = ACCESS_ONCE(rsp->gpnum);
+ *completed = ACCESS_ONCE(rsp->completed);
+ return;
+ }
+ *flags = 0;
+ *gpnum = 0;
+ *completed = 0;
+}
+EXPORT_SYMBOL_GPL(rcutorture_get_gp_data);
+
+/*
* Record the number of writer passes through the current rcutorture test.
* This is also used to correlate debugfs tracing stats with the rcutorture
* messages.
@@ -324,6 +381,28 @@ cpu_has_callbacks_ready_to_invoke(struct rcu_data *rdp)
}
/*
+ * Return the root node of the specified rcu_state structure.
+ */
+static struct rcu_node *rcu_get_root(struct rcu_state *rsp)
+{
+ return &rsp->node[0];
+}
+
+/*
+ * Is there any need for future grace periods?
+ * Interrupts must be disabled. If the caller does not hold the root
+ * rnp_node structure's ->lock, the results are advisory only.
+ */
+static int rcu_future_needs_gp(struct rcu_state *rsp)
+{
+ struct rcu_node *rnp = rcu_get_root(rsp);
+ int idx = (ACCESS_ONCE(rnp->completed) + 1) & 0x1;
+ int *fp = &rnp->need_future_gp[idx];
+
+ return ACCESS_ONCE(*fp);
+}
+
+/*
* Does the current CPU require a not-yet-started grace period?
* The caller must have disabled interrupts to prevent races with
* normal callback registry.
@@ -335,7 +414,7 @@ cpu_needs_another_gp(struct rcu_state *rsp, struct rcu_data *rdp)
if (rcu_gp_in_progress(rsp))
return 0; /* No, a grace period is already in progress. */
- if (rcu_nocb_needs_gp(rsp))
+ if (rcu_future_needs_gp(rsp))
return 1; /* Yes, a no-CBs CPU needs one. */
if (!rdp->nxttail[RCU_NEXT_TAIL])
return 0; /* No, this is a no-CBs (or offline) CPU. */
@@ -350,14 +429,6 @@ cpu_needs_another_gp(struct rcu_state *rsp, struct rcu_data *rdp)
}
/*
- * Return the root node of the specified rcu_state structure.
- */
-static struct rcu_node *rcu_get_root(struct rcu_state *rsp)
-{
- return &rsp->node[0];
-}
-
-/*
* rcu_eqs_enter_common - current CPU is moving towards extended quiescent state
*
* If the new value of the ->dynticks_nesting counter now is zero,
@@ -758,7 +829,12 @@ static int dyntick_save_progress_counter(struct rcu_data *rdp,
{
rdp->dynticks_snap = atomic_add_return(0, &rdp->dynticks->dynticks);
rcu_sysidle_check_cpu(rdp, isidle, maxj);
- return (rdp->dynticks_snap & 0x1) == 0;
+ if ((rdp->dynticks_snap & 0x1) == 0) {
+ trace_rcu_fqs(rdp->rsp->name, rdp->gpnum, rdp->cpu, TPS("dti"));
+ return 1;
+ } else {
+ return 0;
+ }
}
/*
@@ -834,7 +910,7 @@ static int rcu_implicit_dynticks_qs(struct rcu_data *rdp,
* we will beat on the first one until it gets unstuck, then move
* to the next. Only do this for the primary flavor of RCU.
*/
- if (rdp->rsp == rcu_state &&
+ if (rdp->rsp == rcu_state_p &&
ULONG_CMP_GE(jiffies, rdp->rsp->jiffies_resched)) {
rdp->rsp->jiffies_resched += 5;
resched_cpu(rdp->cpu);
@@ -851,7 +927,7 @@ static void record_gp_stall_check_time(struct rcu_state *rsp)
rsp->gp_start = j;
smp_wmb(); /* Record start time before stall time. */
j1 = rcu_jiffies_till_stall_check();
- rsp->jiffies_stall = j + j1;
+ ACCESS_ONCE(rsp->jiffies_stall) = j + j1;
rsp->jiffies_resched = j + j1 / 2;
}
@@ -890,12 +966,12 @@ static void print_other_cpu_stall(struct rcu_state *rsp)
/* Only let one CPU complain about others per time interval. */
raw_spin_lock_irqsave(&rnp->lock, flags);
- delta = jiffies - rsp->jiffies_stall;
+ delta = jiffies - ACCESS_ONCE(rsp->jiffies_stall);
if (delta < RCU_STALL_RAT_DELAY || !rcu_gp_in_progress(rsp)) {
raw_spin_unlock_irqrestore(&rnp->lock, flags);
return;
}
- rsp->jiffies_stall = jiffies + 3 * rcu_jiffies_till_stall_check() + 3;
+ ACCESS_ONCE(rsp->jiffies_stall) = jiffies + 3 * rcu_jiffies_till_stall_check() + 3;
raw_spin_unlock_irqrestore(&rnp->lock, flags);
/*
@@ -932,9 +1008,9 @@ static void print_other_cpu_stall(struct rcu_state *rsp)
print_cpu_stall_info_end();
for_each_possible_cpu(cpu)
totqlen += per_cpu_ptr(rsp->rda, cpu)->qlen;
- pr_cont("(detected by %d, t=%ld jiffies, g=%lu, c=%lu, q=%lu)\n",
+ pr_cont("(detected by %d, t=%ld jiffies, g=%ld, c=%ld, q=%lu)\n",
smp_processor_id(), (long)(jiffies - rsp->gp_start),
- rsp->gpnum, rsp->completed, totqlen);
+ (long)rsp->gpnum, (long)rsp->completed, totqlen);
if (ndetected == 0)
pr_err("INFO: Stall ended before state dump start\n");
else if (!trigger_all_cpu_backtrace())
@@ -947,12 +1023,6 @@ static void print_other_cpu_stall(struct rcu_state *rsp)
force_quiescent_state(rsp); /* Kick them all. */
}
-/*
- * This function really isn't for public consumption, but RCU is special in
- * that context switches can allow the state machine to make progress.
- */
-extern void resched_cpu(int cpu);
-
static void print_cpu_stall(struct rcu_state *rsp)
{
int cpu;
@@ -971,14 +1041,15 @@ static void print_cpu_stall(struct rcu_state *rsp)
print_cpu_stall_info_end();
for_each_possible_cpu(cpu)
totqlen += per_cpu_ptr(rsp->rda, cpu)->qlen;
- pr_cont(" (t=%lu jiffies g=%lu c=%lu q=%lu)\n",
- jiffies - rsp->gp_start, rsp->gpnum, rsp->completed, totqlen);
+ pr_cont(" (t=%lu jiffies g=%ld c=%ld q=%lu)\n",
+ jiffies - rsp->gp_start,
+ (long)rsp->gpnum, (long)rsp->completed, totqlen);
if (!trigger_all_cpu_backtrace())
dump_stack();
raw_spin_lock_irqsave(&rnp->lock, flags);
- if (ULONG_CMP_GE(jiffies, rsp->jiffies_stall))
- rsp->jiffies_stall = jiffies +
+ if (ULONG_CMP_GE(jiffies, ACCESS_ONCE(rsp->jiffies_stall)))
+ ACCESS_ONCE(rsp->jiffies_stall) = jiffies +
3 * rcu_jiffies_till_stall_check() + 3;
raw_spin_unlock_irqrestore(&rnp->lock, flags);
@@ -1062,7 +1133,7 @@ void rcu_cpu_stall_reset(void)
struct rcu_state *rsp;
for_each_rcu_flavor(rsp)
- rsp->jiffies_stall = jiffies + ULONG_MAX / 2;
+ ACCESS_ONCE(rsp->jiffies_stall) = jiffies + ULONG_MAX / 2;
}
/*
@@ -1123,15 +1194,18 @@ static void trace_rcu_future_gp(struct rcu_node *rnp, struct rcu_data *rdp,
/*
* Start some future grace period, as needed to handle newly arrived
* callbacks. The required future grace periods are recorded in each
- * rcu_node structure's ->need_future_gp field.
+ * rcu_node structure's ->need_future_gp field. Returns true if there
+ * is reason to awaken the grace-period kthread.
*
* The caller must hold the specified rcu_node structure's ->lock.
*/
-static unsigned long __maybe_unused
-rcu_start_future_gp(struct rcu_node *rnp, struct rcu_data *rdp)
+static bool __maybe_unused
+rcu_start_future_gp(struct rcu_node *rnp, struct rcu_data *rdp,
+ unsigned long *c_out)
{
unsigned long c;
int i;
+ bool ret = false;
struct rcu_node *rnp_root = rcu_get_root(rdp->rsp);
/*
@@ -1142,7 +1216,7 @@ rcu_start_future_gp(struct rcu_node *rnp, struct rcu_data *rdp)
trace_rcu_future_gp(rnp, rdp, c, TPS("Startleaf"));
if (rnp->need_future_gp[c & 0x1]) {
trace_rcu_future_gp(rnp, rdp, c, TPS("Prestartleaf"));
- return c;
+ goto out;
}
/*
@@ -1156,7 +1230,7 @@ rcu_start_future_gp(struct rcu_node *rnp, struct rcu_data *rdp)
ACCESS_ONCE(rnp->gpnum) != ACCESS_ONCE(rnp->completed)) {
rnp->need_future_gp[c & 0x1]++;
trace_rcu_future_gp(rnp, rdp, c, TPS("Startedleaf"));
- return c;
+ goto out;
}
/*
@@ -1197,12 +1271,15 @@ rcu_start_future_gp(struct rcu_node *rnp, struct rcu_data *rdp)
trace_rcu_future_gp(rnp, rdp, c, TPS("Startedleafroot"));
} else {
trace_rcu_future_gp(rnp, rdp, c, TPS("Startedroot"));
- rcu_start_gp_advanced(rdp->rsp, rnp_root, rdp);
+ ret = rcu_start_gp_advanced(rdp->rsp, rnp_root, rdp);
}
unlock_out:
if (rnp != rnp_root)
raw_spin_unlock(&rnp_root->lock);
- return c;
+out:
+ if (c_out != NULL)
+ *c_out = c;
+ return ret;
}
/*
@@ -1226,25 +1303,43 @@ static int rcu_future_gp_cleanup(struct rcu_state *rsp, struct rcu_node *rnp)
}
/*
+ * Awaken the grace-period kthread for the specified flavor of RCU.
+ * Don't do a self-awaken, and don't bother awakening when there is
+ * nothing for the grace-period kthread to do (as in several CPUs
+ * raced to awaken, and we lost), and finally don't try to awaken
+ * a kthread that has not yet been created.
+ */
+static void rcu_gp_kthread_wake(struct rcu_state *rsp)
+{
+ if (current == rsp->gp_kthread ||
+ !ACCESS_ONCE(rsp->gp_flags) ||
+ !rsp->gp_kthread)
+ return;
+ wake_up(&rsp->gp_wq);
+}
+
+/*
* If there is room, assign a ->completed number to any callbacks on
* this CPU that have not already been assigned. Also accelerate any
* callbacks that were previously assigned a ->completed number that has
* since proven to be too conservative, which can happen if callbacks get
* assigned a ->completed number while RCU is idle, but with reference to
* a non-root rcu_node structure. This function is idempotent, so it does
- * not hurt to call it repeatedly.
+ * not hurt to call it repeatedly. Returns an flag saying that we should
+ * awaken the RCU grace-period kthread.
*
* The caller must hold rnp->lock with interrupts disabled.
*/
-static void rcu_accelerate_cbs(struct rcu_state *rsp, struct rcu_node *rnp,
+static bool rcu_accelerate_cbs(struct rcu_state *rsp, struct rcu_node *rnp,
struct rcu_data *rdp)
{
unsigned long c;
int i;
+ bool ret;
/* If the CPU has no callbacks, nothing to do. */
if (!rdp->nxttail[RCU_NEXT_TAIL] || !*rdp->nxttail[RCU_DONE_TAIL])
- return;
+ return false;
/*
* Starting from the sublist containing the callbacks most
@@ -1273,7 +1368,7 @@ static void rcu_accelerate_cbs(struct rcu_state *rsp, struct rcu_node *rnp,
* be grouped into.
*/
if (++i >= RCU_NEXT_TAIL)
- return;
+ return false;
/*
* Assign all subsequent callbacks' ->completed number to the next
@@ -1285,13 +1380,14 @@ static void rcu_accelerate_cbs(struct rcu_state *rsp, struct rcu_node *rnp,
rdp->nxtcompleted[i] = c;
}
/* Record any needed additional grace periods. */
- rcu_start_future_gp(rnp, rdp);
+ ret = rcu_start_future_gp(rnp, rdp, NULL);
/* Trace depending on how much we were able to accelerate. */
if (!*rdp->nxttail[RCU_WAIT_TAIL])
trace_rcu_grace_period(rsp->name, rdp->gpnum, TPS("AccWaitCB"));
else
trace_rcu_grace_period(rsp->name, rdp->gpnum, TPS("AccReadyCB"));
+ return ret;
}
/*
@@ -1300,17 +1396,18 @@ static void rcu_accelerate_cbs(struct rcu_state *rsp, struct rcu_node *rnp,
* assign ->completed numbers to any callbacks in the RCU_NEXT_TAIL
* sublist. This function is idempotent, so it does not hurt to
* invoke it repeatedly. As long as it is not invoked -too- often...
+ * Returns true if the RCU grace-period kthread needs to be awakened.
*
* The caller must hold rnp->lock with interrupts disabled.
*/
-static void rcu_advance_cbs(struct rcu_state *rsp, struct rcu_node *rnp,
+static bool rcu_advance_cbs(struct rcu_state *rsp, struct rcu_node *rnp,
struct rcu_data *rdp)
{
int i, j;
/* If the CPU has no callbacks, nothing to do. */
if (!rdp->nxttail[RCU_NEXT_TAIL] || !*rdp->nxttail[RCU_DONE_TAIL])
- return;
+ return false;
/*
* Find all callbacks whose ->completed numbers indicate that they
@@ -1334,26 +1431,30 @@ static void rcu_advance_cbs(struct rcu_state *rsp, struct rcu_node *rnp,
}
/* Classify any remaining callbacks. */
- rcu_accelerate_cbs(rsp, rnp, rdp);
+ return rcu_accelerate_cbs(rsp, rnp, rdp);
}
/*
* Update CPU-local rcu_data state to record the beginnings and ends of
* grace periods. The caller must hold the ->lock of the leaf rcu_node
* structure corresponding to the current CPU, and must have irqs disabled.
+ * Returns true if the grace-period kthread needs to be awakened.
*/
-static void __note_gp_changes(struct rcu_state *rsp, struct rcu_node *rnp, struct rcu_data *rdp)
+static bool __note_gp_changes(struct rcu_state *rsp, struct rcu_node *rnp,
+ struct rcu_data *rdp)
{
+ bool ret;
+
/* Handle the ends of any preceding grace periods first. */
if (rdp->completed == rnp->completed) {
/* No grace period end, so just accelerate recent callbacks. */
- rcu_accelerate_cbs(rsp, rnp, rdp);
+ ret = rcu_accelerate_cbs(rsp, rnp, rdp);
} else {
/* Advance callbacks. */
- rcu_advance_cbs(rsp, rnp, rdp);
+ ret = rcu_advance_cbs(rsp, rnp, rdp);
/* Remember that we saw this grace-period completion. */
rdp->completed = rnp->completed;
@@ -1372,11 +1473,13 @@ static void __note_gp_changes(struct rcu_state *rsp, struct rcu_node *rnp, struc
rdp->qs_pending = !!(rnp->qsmask & rdp->grpmask);
zero_cpu_stall_ticks(rdp);
}
+ return ret;
}
static void note_gp_changes(struct rcu_state *rsp, struct rcu_data *rdp)
{
unsigned long flags;
+ bool needwake;
struct rcu_node *rnp;
local_irq_save(flags);
@@ -1388,8 +1491,10 @@ static void note_gp_changes(struct rcu_state *rsp, struct rcu_data *rdp)
return;
}
smp_mb__after_unlock_lock();
- __note_gp_changes(rsp, rnp, rdp);
+ needwake = __note_gp_changes(rsp, rnp, rdp);
raw_spin_unlock_irqrestore(&rnp->lock, flags);
+ if (needwake)
+ rcu_gp_kthread_wake(rsp);
}
/*
@@ -1403,12 +1508,12 @@ static int rcu_gp_init(struct rcu_state *rsp)
rcu_bind_gp_kthread();
raw_spin_lock_irq(&rnp->lock);
smp_mb__after_unlock_lock();
- if (rsp->gp_flags == 0) {
+ if (!ACCESS_ONCE(rsp->gp_flags)) {
/* Spurious wakeup, tell caller to go back to sleep. */
raw_spin_unlock_irq(&rnp->lock);
return 0;
}
- rsp->gp_flags = 0; /* Clear all flags: New grace period. */
+ ACCESS_ONCE(rsp->gp_flags) = 0; /* Clear all flags: New grace period. */
if (WARN_ON_ONCE(rcu_gp_in_progress(rsp))) {
/*
@@ -1453,7 +1558,7 @@ static int rcu_gp_init(struct rcu_state *rsp)
WARN_ON_ONCE(rnp->completed != rsp->completed);
ACCESS_ONCE(rnp->completed) = rsp->completed;
if (rnp == rdp->mynode)
- __note_gp_changes(rsp, rnp, rdp);
+ (void)__note_gp_changes(rsp, rnp, rdp);
rcu_preempt_boost_start_gp(rnp);
trace_rcu_grace_period_init(rsp->name, rnp->gpnum,
rnp->level, rnp->grplo,
@@ -1501,7 +1606,7 @@ static int rcu_gp_fqs(struct rcu_state *rsp, int fqs_state_in)
if (ACCESS_ONCE(rsp->gp_flags) & RCU_GP_FLAG_FQS) {
raw_spin_lock_irq(&rnp->lock);
smp_mb__after_unlock_lock();
- rsp->gp_flags &= ~RCU_GP_FLAG_FQS;
+ ACCESS_ONCE(rsp->gp_flags) &= ~RCU_GP_FLAG_FQS;
raw_spin_unlock_irq(&rnp->lock);
}
return fqs_state;
@@ -1513,6 +1618,7 @@ static int rcu_gp_fqs(struct rcu_state *rsp, int fqs_state_in)
static void rcu_gp_cleanup(struct rcu_state *rsp)
{
unsigned long gp_duration;
+ bool needgp = false;
int nocb = 0;
struct rcu_data *rdp;
struct rcu_node *rnp = rcu_get_root(rsp);
@@ -1548,7 +1654,7 @@ static void rcu_gp_cleanup(struct rcu_state *rsp)
ACCESS_ONCE(rnp->completed) = rsp->gpnum;
rdp = this_cpu_ptr(rsp->rda);
if (rnp == rdp->mynode)
- __note_gp_changes(rsp, rnp, rdp);
+ needgp = __note_gp_changes(rsp, rnp, rdp) || needgp;
/* smp_mb() provided by prior unlock-lock pair. */
nocb += rcu_future_gp_cleanup(rsp, rnp);
raw_spin_unlock_irq(&rnp->lock);
@@ -1564,9 +1670,10 @@ static void rcu_gp_cleanup(struct rcu_state *rsp)
trace_rcu_grace_period(rsp->name, rsp->completed, TPS("end"));
rsp->fqs_state = RCU_GP_IDLE;
rdp = this_cpu_ptr(rsp->rda);
- rcu_advance_cbs(rsp, rnp, rdp); /* Reduce false positives below. */
- if (cpu_needs_another_gp(rsp, rdp)) {
- rsp->gp_flags = RCU_GP_FLAG_INIT;
+ /* Advance CBs to reduce false positives below. */
+ needgp = rcu_advance_cbs(rsp, rnp, rdp) || needgp;
+ if (needgp || cpu_needs_another_gp(rsp, rdp)) {
+ ACCESS_ONCE(rsp->gp_flags) = RCU_GP_FLAG_INIT;
trace_rcu_grace_period(rsp->name,
ACCESS_ONCE(rsp->gpnum),
TPS("newreq"));
@@ -1593,6 +1700,7 @@ static int __noreturn rcu_gp_kthread(void *arg)
trace_rcu_grace_period(rsp->name,
ACCESS_ONCE(rsp->gpnum),
TPS("reqwait"));
+ rsp->gp_state = RCU_GP_WAIT_GPS;
wait_event_interruptible(rsp->gp_wq,
ACCESS_ONCE(rsp->gp_flags) &
RCU_GP_FLAG_INIT);
@@ -1620,6 +1728,7 @@ static int __noreturn rcu_gp_kthread(void *arg)
trace_rcu_grace_period(rsp->name,
ACCESS_ONCE(rsp->gpnum),
TPS("fqswait"));
+ rsp->gp_state = RCU_GP_WAIT_FQS;
ret = wait_event_interruptible_timeout(rsp->gp_wq,
((gf = ACCESS_ONCE(rsp->gp_flags)) &
RCU_GP_FLAG_FQS) ||
@@ -1665,14 +1774,6 @@ static int __noreturn rcu_gp_kthread(void *arg)
}
}
-static void rsp_wakeup(struct irq_work *work)
-{
- struct rcu_state *rsp = container_of(work, struct rcu_state, wakeup_work);
-
- /* Wake up rcu_gp_kthread() to start the grace period. */
- wake_up(&rsp->gp_wq);
-}
-
/*
* Start a new RCU grace period if warranted, re-initializing the hierarchy
* in preparation for detecting the next grace period. The caller must hold
@@ -1681,8 +1782,10 @@ static void rsp_wakeup(struct irq_work *work)
* Note that it is legal for a dying CPU (which is marked as offline) to
* invoke this function. This can happen when the dying CPU reports its
* quiescent state.
+ *
+ * Returns true if the grace-period kthread must be awakened.
*/
-static void
+static bool
rcu_start_gp_advanced(struct rcu_state *rsp, struct rcu_node *rnp,
struct rcu_data *rdp)
{
@@ -1693,20 +1796,18 @@ rcu_start_gp_advanced(struct rcu_state *rsp, struct rcu_node *rnp,
* or a grace period is already in progress.
* Either way, don't start a new grace period.
*/
- return;
+ return false;
}
- rsp->gp_flags = RCU_GP_FLAG_INIT;
+ ACCESS_ONCE(rsp->gp_flags) = RCU_GP_FLAG_INIT;
trace_rcu_grace_period(rsp->name, ACCESS_ONCE(rsp->gpnum),
TPS("newreq"));
/*
* We can't do wakeups while holding the rnp->lock, as that
* could cause possible deadlocks with the rq->lock. Defer
- * the wakeup to interrupt context. And don't bother waking
- * up the running kthread.
+ * the wakeup to our caller.
*/
- if (current != rsp->gp_kthread)
- irq_work_queue(&rsp->wakeup_work);
+ return true;
}
/*
@@ -1715,12 +1816,14 @@ rcu_start_gp_advanced(struct rcu_state *rsp, struct rcu_node *rnp,
* is invoked indirectly from rcu_advance_cbs(), which would result in
* endless recursion -- or would do so if it wasn't for the self-deadlock
* that is encountered beforehand.
+ *
+ * Returns true if the grace-period kthread needs to be awakened.
*/
-static void
-rcu_start_gp(struct rcu_state *rsp)
+static bool rcu_start_gp(struct rcu_state *rsp)
{
struct rcu_data *rdp = this_cpu_ptr(rsp->rda);
struct rcu_node *rnp = rcu_get_root(rsp);
+ bool ret = false;
/*
* If there is no grace period in progress right now, any
@@ -1730,8 +1833,9 @@ rcu_start_gp(struct rcu_state *rsp)
* resulting in pointless grace periods. So, advance callbacks
* then start the grace period!
*/
- rcu_advance_cbs(rsp, rnp, rdp);
- rcu_start_gp_advanced(rsp, rnp, rdp);
+ ret = rcu_advance_cbs(rsp, rnp, rdp) || ret;
+ ret = rcu_start_gp_advanced(rsp, rnp, rdp) || ret;
+ return ret;
}
/*
@@ -1820,6 +1924,7 @@ rcu_report_qs_rdp(int cpu, struct rcu_state *rsp, struct rcu_data *rdp)
{
unsigned long flags;
unsigned long mask;
+ bool needwake;
struct rcu_node *rnp;
rnp = rdp->mynode;
@@ -1848,9 +1953,11 @@ rcu_report_qs_rdp(int cpu, struct rcu_state *rsp, struct rcu_data *rdp)
* This GP can't end until cpu checks in, so all of our
* callbacks can be processed during the next GP.
*/
- rcu_accelerate_cbs(rsp, rnp, rdp);
+ needwake = rcu_accelerate_cbs(rsp, rnp, rdp);
rcu_report_qs_rnp(mask, rsp, rnp, flags); /* rlses rnp->lock */
+ if (needwake)
+ rcu_gp_kthread_wake(rsp);
}
}
@@ -1951,7 +2058,7 @@ rcu_send_cbs_to_orphanage(int cpu, struct rcu_state *rsp,
static void rcu_adopt_orphan_cbs(struct rcu_state *rsp, unsigned long flags)
{
int i;
- struct rcu_data *rdp = __this_cpu_ptr(rsp->rda);
+ struct rcu_data *rdp = raw_cpu_ptr(rsp->rda);
/* No-CBs CPUs are handled specially. */
if (rcu_nocb_adopt_orphan_cbs(rsp, rdp, flags))
@@ -2320,7 +2427,7 @@ static void force_quiescent_state(struct rcu_state *rsp)
raw_spin_unlock_irqrestore(&rnp_old->lock, flags);
return; /* Someone beat us to it. */
}
- rsp->gp_flags |= RCU_GP_FLAG_FQS;
+ ACCESS_ONCE(rsp->gp_flags) |= RCU_GP_FLAG_FQS;
raw_spin_unlock_irqrestore(&rnp_old->lock, flags);
wake_up(&rsp->gp_wq); /* Memory barrier implied by wake_up() path. */
}
@@ -2334,7 +2441,8 @@ static void
__rcu_process_callbacks(struct rcu_state *rsp)
{
unsigned long flags;
- struct rcu_data *rdp = __this_cpu_ptr(rsp->rda);
+ bool needwake;
+ struct rcu_data *rdp = raw_cpu_ptr(rsp->rda);
WARN_ON_ONCE(rdp->beenonline == 0);
@@ -2345,8 +2453,10 @@ __rcu_process_callbacks(struct rcu_state *rsp)
local_irq_save(flags);
if (cpu_needs_another_gp(rsp, rdp)) {
raw_spin_lock(&rcu_get_root(rsp)->lock); /* irqs disabled. */
- rcu_start_gp(rsp);
+ needwake = rcu_start_gp(rsp);
raw_spin_unlock_irqrestore(&rcu_get_root(rsp)->lock, flags);
+ if (needwake)
+ rcu_gp_kthread_wake(rsp);
} else {
local_irq_restore(flags);
}
@@ -2404,6 +2514,8 @@ static void invoke_rcu_core(void)
static void __call_rcu_core(struct rcu_state *rsp, struct rcu_data *rdp,
struct rcu_head *head, unsigned long flags)
{
+ bool needwake;
+
/*
* If called from an extended quiescent state, invoke the RCU
* core in order to force a re-evaluation of RCU's idleness.
@@ -2433,8 +2545,10 @@ static void __call_rcu_core(struct rcu_state *rsp, struct rcu_data *rdp,
raw_spin_lock(&rnp_root->lock);
smp_mb__after_unlock_lock();
- rcu_start_gp(rsp);
+ needwake = rcu_start_gp(rsp);
raw_spin_unlock(&rnp_root->lock);
+ if (needwake)
+ rcu_gp_kthread_wake(rsp);
} else {
/* Give the grace period a kick. */
rdp->blimit = LONG_MAX;
@@ -2537,6 +2651,20 @@ void call_rcu_bh(struct rcu_head *head, void (*func)(struct rcu_head *rcu))
EXPORT_SYMBOL_GPL(call_rcu_bh);
/*
+ * Queue an RCU callback for lazy invocation after a grace period.
+ * This will likely be later named something like "call_rcu_lazy()",
+ * but this change will require some way of tagging the lazy RCU
+ * callbacks in the list of pending callbacks. Until then, this
+ * function may only be called from __kfree_rcu().
+ */
+void kfree_call_rcu(struct rcu_head *head,
+ void (*func)(struct rcu_head *rcu))
+{
+ __call_rcu(head, func, rcu_state_p, -1, 1);
+}
+EXPORT_SYMBOL_GPL(kfree_call_rcu);
+
+/*
* Because a context switch is a grace period for RCU-sched and RCU-bh,
* any blocking grace-period wait automatically implies a grace period
* if there is only one CPU online at any point time during execution
@@ -2659,7 +2787,7 @@ unsigned long get_state_synchronize_rcu(void)
* time-consuming work between get_state_synchronize_rcu()
* and cond_synchronize_rcu().
*/
- return smp_load_acquire(&rcu_state->gpnum);
+ return smp_load_acquire(&rcu_state_p->gpnum);
}
EXPORT_SYMBOL_GPL(get_state_synchronize_rcu);
@@ -2685,7 +2813,7 @@ void cond_synchronize_rcu(unsigned long oldstate)
* Ensure that this load happens before any RCU-destructive
* actions the caller might carry out after we return.
*/
- newstate = smp_load_acquire(&rcu_state->completed);
+ newstate = smp_load_acquire(&rcu_state_p->completed);
if (ULONG_CMP_GE(oldstate, newstate))
synchronize_rcu();
}
@@ -2988,7 +3116,7 @@ static void rcu_barrier_callback(struct rcu_head *rhp)
static void rcu_barrier_func(void *type)
{
struct rcu_state *rsp = type;
- struct rcu_data *rdp = __this_cpu_ptr(rsp->rda);
+ struct rcu_data *rdp = raw_cpu_ptr(rsp->rda);
_rcu_barrier_trace(rsp, "IRQ", -1, rsp->n_barrier_done);
atomic_inc(&rsp->barrier_cpu_count);
@@ -3160,7 +3288,7 @@ rcu_boot_init_percpu_data(int cpu, struct rcu_state *rsp)
* that this CPU cannot possibly have any RCU callbacks in flight yet.
*/
static void
-rcu_init_percpu_data(int cpu, struct rcu_state *rsp, int preemptible)
+rcu_init_percpu_data(int cpu, struct rcu_state *rsp)
{
unsigned long flags;
unsigned long mask;
@@ -3173,7 +3301,6 @@ rcu_init_percpu_data(int cpu, struct rcu_state *rsp, int preemptible)
/* Set up local state, ensuring consistent view of global state. */
raw_spin_lock_irqsave(&rnp->lock, flags);
rdp->beenonline = 1; /* We have now been online. */
- rdp->preemptible = preemptible;
rdp->qlen_last_fqs_check = 0;
rdp->n_force_qs_snap = rsp->n_force_qs;
rdp->blimit = blimit;
@@ -3217,8 +3344,7 @@ static void rcu_prepare_cpu(int cpu)
struct rcu_state *rsp;
for_each_rcu_flavor(rsp)
- rcu_init_percpu_data(cpu, rsp,
- strcmp(rsp->name, "rcu_preempt") == 0);
+ rcu_init_percpu_data(cpu, rsp);
}
/*
@@ -3228,7 +3354,7 @@ static int rcu_cpu_notify(struct notifier_block *self,
unsigned long action, void *hcpu)
{
long cpu = (long)hcpu;
- struct rcu_data *rdp = per_cpu_ptr(rcu_state->rda, cpu);
+ struct rcu_data *rdp = per_cpu_ptr(rcu_state_p->rda, cpu);
struct rcu_node *rnp = rdp->mynode;
struct rcu_state *rsp;
@@ -3402,8 +3528,8 @@ static void __init rcu_init_one(struct rcu_state *rsp,
rnp->qsmaskinit = 0;
rnp->grplo = j * cpustride;
rnp->grphi = (j + 1) * cpustride - 1;
- if (rnp->grphi >= NR_CPUS)
- rnp->grphi = NR_CPUS - 1;
+ if (rnp->grphi >= nr_cpu_ids)
+ rnp->grphi = nr_cpu_ids - 1;
if (i == 0) {
rnp->grpnum = 0;
rnp->grpmask = 0;
@@ -3422,7 +3548,6 @@ static void __init rcu_init_one(struct rcu_state *rsp,
rsp->rda = rda;
init_waitqueue_head(&rsp->gp_wq);
- init_irq_work(&rsp->wakeup_work, rsp_wakeup);
rnp = rsp->level[rcu_num_lvls - 1];
for_each_possible_cpu(i) {
while (i > rnp->grphi)
diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h
index 75dc3c3..bf2c1e6 100644
--- a/kernel/rcu/tree.h
+++ b/kernel/rcu/tree.h
@@ -252,7 +252,6 @@ struct rcu_data {
bool passed_quiesce; /* User-mode/idle loop etc. */
bool qs_pending; /* Core waits for quiesc state. */
bool beenonline; /* CPU online at least once. */
- bool preemptible; /* Preemptible RCU? */
struct rcu_node *mynode; /* This CPU's leaf of hierarchy */
unsigned long grpmask; /* Mask to apply to leaf qsmask. */
#ifdef CONFIG_RCU_CPU_STALL_INFO
@@ -406,7 +405,8 @@ struct rcu_state {
unsigned long completed; /* # of last completed gp. */
struct task_struct *gp_kthread; /* Task for grace periods. */
wait_queue_head_t gp_wq; /* Where GP task waits. */
- int gp_flags; /* Commands for GP task. */
+ short gp_flags; /* Commands for GP task. */
+ short gp_state; /* GP kthread sleep state. */
/* End of fields guarded by root rcu_node's lock. */
@@ -462,13 +462,17 @@ struct rcu_state {
const char *name; /* Name of structure. */
char abbr; /* Abbreviated name. */
struct list_head flavors; /* List of RCU flavors. */
- struct irq_work wakeup_work; /* Postponed wakeups */
};
/* Values for rcu_state structure's gp_flags field. */
#define RCU_GP_FLAG_INIT 0x1 /* Need grace-period initialization. */
#define RCU_GP_FLAG_FQS 0x2 /* Need grace-period quiescent-state forcing. */
+/* Values for rcu_state structure's gp_flags field. */
+#define RCU_GP_WAIT_INIT 0 /* Initial state. */
+#define RCU_GP_WAIT_GPS 1 /* Wait for grace-period start. */
+#define RCU_GP_WAIT_FQS 2 /* Wait for force-quiescent-state time. */
+
extern struct list_head rcu_struct_flavors;
/* Sequence through rcu_state structures for each RCU flavor. */
@@ -547,7 +551,6 @@ static void print_cpu_stall_info(struct rcu_state *rsp, int cpu);
static void print_cpu_stall_info_end(void);
static void zero_cpu_stall_ticks(struct rcu_data *rdp);
static void increment_cpu_stall_ticks(void);
-static int rcu_nocb_needs_gp(struct rcu_state *rsp);
static void rcu_nocb_gp_set(struct rcu_node *rnp, int nrq);
static void rcu_nocb_gp_cleanup(struct rcu_state *rsp, struct rcu_node *rnp);
static void rcu_init_one_nocb(struct rcu_node *rnp);
diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index 962d1d5..29977ae 100644
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -116,7 +116,7 @@ static void __init rcu_bootup_announce_oddness(void)
#ifdef CONFIG_TREE_PREEMPT_RCU
RCU_STATE_INITIALIZER(rcu_preempt, 'p', call_rcu);
-static struct rcu_state *rcu_state = &rcu_preempt_state;
+static struct rcu_state *rcu_state_p = &rcu_preempt_state;
static int rcu_preempted_readers_exp(struct rcu_node *rnp);
@@ -149,15 +149,6 @@ long rcu_batches_completed(void)
EXPORT_SYMBOL_GPL(rcu_batches_completed);
/*
- * Force a quiescent state for preemptible RCU.
- */
-void rcu_force_quiescent_state(void)
-{
- force_quiescent_state(&rcu_preempt_state);
-}
-EXPORT_SYMBOL_GPL(rcu_force_quiescent_state);
-
-/*
* Record a preemptible-RCU quiescent state for the specified CPU. Note
* that this just means that the task currently running on the CPU is
* not in a quiescent state. There might be any number of tasks blocked
@@ -688,20 +679,6 @@ void call_rcu(struct rcu_head *head, void (*func)(struct rcu_head *rcu))
}
EXPORT_SYMBOL_GPL(call_rcu);
-/*
- * Queue an RCU callback for lazy invocation after a grace period.
- * This will likely be later named something like "call_rcu_lazy()",
- * but this change will require some way of tagging the lazy RCU
- * callbacks in the list of pending callbacks. Until then, this
- * function may only be called from __kfree_rcu().
- */
-void kfree_call_rcu(struct rcu_head *head,
- void (*func)(struct rcu_head *rcu))
-{
- __call_rcu(head, func, &rcu_preempt_state, -1, 1);
-}
-EXPORT_SYMBOL_GPL(kfree_call_rcu);
-
/**
* synchronize_rcu - wait until a grace period has elapsed.
*
@@ -970,7 +947,7 @@ void exit_rcu(void)
#else /* #ifdef CONFIG_TREE_PREEMPT_RCU */
-static struct rcu_state *rcu_state = &rcu_sched_state;
+static struct rcu_state *rcu_state_p = &rcu_sched_state;
/*
* Tell them what RCU they are running.
@@ -991,16 +968,6 @@ long rcu_batches_completed(void)
EXPORT_SYMBOL_GPL(rcu_batches_completed);
/*
- * Force a quiescent state for RCU, which, because there is no preemptible
- * RCU, becomes the same as rcu-sched.
- */
-void rcu_force_quiescent_state(void)
-{
- rcu_sched_force_quiescent_state();
-}
-EXPORT_SYMBOL_GPL(rcu_force_quiescent_state);
-
-/*
* Because preemptible RCU does not exist, we never have to check for
* CPUs being in quiescent states.
*/
@@ -1080,22 +1047,6 @@ static void rcu_preempt_check_callbacks(int cpu)
}
/*
- * Queue an RCU callback for lazy invocation after a grace period.
- * This will likely be later named something like "call_rcu_lazy()",
- * but this change will require some way of tagging the lazy RCU
- * callbacks in the list of pending callbacks. Until then, this
- * function may only be called from __kfree_rcu().
- *
- * Because there is no preemptible RCU, we use RCU-sched instead.
- */
-void kfree_call_rcu(struct rcu_head *head,
- void (*func)(struct rcu_head *rcu))
-{
- __call_rcu(head, func, &rcu_sched_state, -1, 1);
-}
-EXPORT_SYMBOL_GPL(kfree_call_rcu);
-
-/*
* Wait for an rcu-preempt grace period, but make it happen quickly.
* But because preemptible RCU does not exist, map to rcu-sched.
*/
@@ -1517,11 +1468,11 @@ static int __init rcu_spawn_kthreads(void)
for_each_possible_cpu(cpu)
per_cpu(rcu_cpu_has_work, cpu) = 0;
BUG_ON(smpboot_register_percpu_thread(&rcu_cpu_thread_spec));
- rnp = rcu_get_root(rcu_state);
- (void)rcu_spawn_one_boost_kthread(rcu_state, rnp);
+ rnp = rcu_get_root(rcu_state_p);
+ (void)rcu_spawn_one_boost_kthread(rcu_state_p, rnp);
if (NUM_RCU_NODES > 1) {
- rcu_for_each_leaf_node(rcu_state, rnp)
- (void)rcu_spawn_one_boost_kthread(rcu_state, rnp);
+ rcu_for_each_leaf_node(rcu_state_p, rnp)
+ (void)rcu_spawn_one_boost_kthread(rcu_state_p, rnp);
}
return 0;
}
@@ -1529,12 +1480,12 @@ early_initcall(rcu_spawn_kthreads);
static void rcu_prepare_kthreads(int cpu)
{
- struct rcu_data *rdp = per_cpu_ptr(rcu_state->rda, cpu);
+ struct rcu_data *rdp = per_cpu_ptr(rcu_state_p->rda, cpu);
struct rcu_node *rnp = rdp->mynode;
/* Fire up the incoming CPU's kthread and leaf rcu_node kthread. */
if (rcu_scheduler_fully_active)
- (void)rcu_spawn_one_boost_kthread(rcu_state, rnp);
+ (void)rcu_spawn_one_boost_kthread(rcu_state_p, rnp);
}
#else /* #ifdef CONFIG_RCU_BOOST */
@@ -1744,6 +1695,7 @@ int rcu_needs_cpu(int cpu, unsigned long *dj)
static void rcu_prepare_for_idle(int cpu)
{
#ifndef CONFIG_RCU_NOCB_CPU_ALL
+ bool needwake;
struct rcu_data *rdp;
struct rcu_dynticks *rdtp = &per_cpu(rcu_dynticks, cpu);
struct rcu_node *rnp;
@@ -1792,8 +1744,10 @@ static void rcu_prepare_for_idle(int cpu)
rnp = rdp->mynode;
raw_spin_lock(&rnp->lock); /* irqs already disabled. */
smp_mb__after_unlock_lock();
- rcu_accelerate_cbs(rsp, rnp, rdp);
+ needwake = rcu_accelerate_cbs(rsp, rnp, rdp);
raw_spin_unlock(&rnp->lock); /* irqs remain disabled. */
+ if (needwake)
+ rcu_gp_kthread_wake(rsp);
}
#endif /* #ifndef CONFIG_RCU_NOCB_CPU_ALL */
}
@@ -1855,7 +1809,7 @@ static void rcu_oom_notify_cpu(void *unused)
struct rcu_data *rdp;
for_each_rcu_flavor(rsp) {
- rdp = __this_cpu_ptr(rsp->rda);
+ rdp = raw_cpu_ptr(rsp->rda);
if (rdp->qlen_lazy != 0) {
atomic_inc(&oom_callback_count);
rsp->call(&rdp->oom_head, rcu_oom_callback);
@@ -1997,7 +1951,7 @@ static void increment_cpu_stall_ticks(void)
struct rcu_state *rsp;
for_each_rcu_flavor(rsp)
- __this_cpu_ptr(rsp->rda)->ticks_this_gp++;
+ raw_cpu_inc(rsp->rda->ticks_this_gp);
}
#else /* #ifdef CONFIG_RCU_CPU_STALL_INFO */
@@ -2068,19 +2022,6 @@ static int __init parse_rcu_nocb_poll(char *arg)
early_param("rcu_nocb_poll", parse_rcu_nocb_poll);
/*
- * Do any no-CBs CPUs need another grace period?
- *
- * Interrupts must be disabled. If the caller does not hold the root
- * rnp_node structure's ->lock, the results are advisory only.
- */
-static int rcu_nocb_needs_gp(struct rcu_state *rsp)
-{
- struct rcu_node *rnp = rcu_get_root(rsp);
-
- return rnp->need_future_gp[(ACCESS_ONCE(rnp->completed) + 1) & 0x1];
-}
-
-/*
* Wake up any no-CBs CPUs' kthreads that were waiting on the just-ended
* grace period.
*/
@@ -2109,7 +2050,7 @@ static void rcu_init_one_nocb(struct rcu_node *rnp)
}
#ifndef CONFIG_RCU_NOCB_CPU_ALL
-/* Is the specified CPU a no-CPUs CPU? */
+/* Is the specified CPU a no-CBs CPU? */
bool rcu_is_nocb_cpu(int cpu)
{
if (have_rcu_nocb_mask)
@@ -2243,12 +2184,15 @@ static void rcu_nocb_wait_gp(struct rcu_data *rdp)
unsigned long c;
bool d;
unsigned long flags;
+ bool needwake;
struct rcu_node *rnp = rdp->mynode;
raw_spin_lock_irqsave(&rnp->lock, flags);
smp_mb__after_unlock_lock();
- c = rcu_start_future_gp(rnp, rdp);
+ needwake = rcu_start_future_gp(rnp, rdp, &c);
raw_spin_unlock_irqrestore(&rnp->lock, flags);
+ if (needwake)
+ rcu_gp_kthread_wake(rdp->rsp);
/*
* Wait for the grace period. Do so interruptibly to avoid messing
@@ -2402,11 +2346,6 @@ static bool init_nocb_callback_list(struct rcu_data *rdp)
#else /* #ifdef CONFIG_RCU_NOCB_CPU */
-static int rcu_nocb_needs_gp(struct rcu_state *rsp)
-{
- return 0;
-}
-
static void rcu_nocb_gp_cleanup(struct rcu_state *rsp, struct rcu_node *rnp)
{
}
@@ -2657,20 +2596,6 @@ static bool is_sysidle_rcu_state(struct rcu_state *rsp)
}
/*
- * Bind the grace-period kthread for the sysidle flavor of RCU to the
- * timekeeping CPU.
- */
-static void rcu_bind_gp_kthread(void)
-{
- int cpu = ACCESS_ONCE(tick_do_timer_cpu);
-
- if (cpu < 0 || cpu >= nr_cpu_ids)
- return;
- if (raw_smp_processor_id() != cpu)
- set_cpus_allowed_ptr(current, cpumask_of(cpu));
-}
-
-/*
* Return a delay in jiffies based on the number of CPUs, rcu_node
* leaf fanout, and jiffies tick rate. The idea is to allow larger
* systems more time to transition to full-idle state in order to
@@ -2734,7 +2659,8 @@ static void rcu_sysidle(unsigned long j)
static void rcu_sysidle_cancel(void)
{
smp_mb();
- ACCESS_ONCE(full_sysidle_state) = RCU_SYSIDLE_NOT;
+ if (full_sysidle_state > RCU_SYSIDLE_SHORT)
+ ACCESS_ONCE(full_sysidle_state) = RCU_SYSIDLE_NOT;
}
/*
@@ -2880,10 +2806,6 @@ static bool is_sysidle_rcu_state(struct rcu_state *rsp)
return false;
}
-static void rcu_bind_gp_kthread(void)
-{
-}
-
static void rcu_sysidle_report_gp(struct rcu_state *rsp, int isidle,
unsigned long maxj)
{
@@ -2914,3 +2836,19 @@ static bool rcu_nohz_full_cpu(struct rcu_state *rsp)
#endif /* #ifdef CONFIG_NO_HZ_FULL */
return 0;
}
+
+/*
+ * Bind the grace-period kthread for the sysidle flavor of RCU to the
+ * timekeeping CPU.
+ */
+static void rcu_bind_gp_kthread(void)
+{
+#ifdef CONFIG_NO_HZ_FULL
+ int cpu = ACCESS_ONCE(tick_do_timer_cpu);
+
+ if (cpu < 0 || cpu >= nr_cpu_ids)
+ return;
+ if (raw_smp_processor_id() != cpu)
+ set_cpus_allowed_ptr(current, cpumask_of(cpu));
+#endif /* #ifdef CONFIG_NO_HZ_FULL */
+}
diff --git a/kernel/rcu/update.c b/kernel/rcu/update.c
index 4c0a9b0..a2aeb4d 100644
--- a/kernel/rcu/update.c
+++ b/kernel/rcu/update.c
@@ -320,6 +320,18 @@ int rcu_jiffies_till_stall_check(void)
return till_stall_check * HZ + RCU_STALL_DELAY_DELTA;
}
+void rcu_sysrq_start(void)
+{
+ if (!rcu_cpu_stall_suppress)
+ rcu_cpu_stall_suppress = 2;
+}
+
+void rcu_sysrq_end(void)
+{
+ if (rcu_cpu_stall_suppress == 2)
+ rcu_cpu_stall_suppress = 0;
+}
+
static int rcu_panic(struct notifier_block *this, unsigned long ev, void *ptr)
{
rcu_cpu_stall_suppress = 1;
@@ -338,3 +350,21 @@ static int __init check_cpu_stall_init(void)
early_initcall(check_cpu_stall_init);
#endif /* #ifdef CONFIG_RCU_STALL_COMMON */
+
+/*
+ * Hooks for cond_resched() and friends to avoid RCU CPU stall warnings.
+ */
+
+DEFINE_PER_CPU(int, rcu_cond_resched_count);
+
+/*
+ * Report a set of RCU quiescent states, for use by cond_resched()
+ * and friends. Out of line due to being called infrequently.
+ */
+void rcu_resched(void)
+{
+ preempt_disable();
+ __this_cpu_write(rcu_cond_resched_count, 0);
+ rcu_note_context_switch(smp_processor_id());
+ preempt_enable();
+}
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index d9d8ece..64f71f1 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -4051,6 +4051,7 @@ static void __cond_resched(void)
int __sched _cond_resched(void)
{
+ rcu_cond_resched();
if (should_resched()) {
__cond_resched();
return 1;
@@ -4069,15 +4070,18 @@ EXPORT_SYMBOL(_cond_resched);
*/
int __cond_resched_lock(spinlock_t *lock)
{
+ bool need_rcu_resched = rcu_should_resched();
int resched = should_resched();
int ret = 0;
lockdep_assert_held(lock);
- if (spin_needbreak(lock) || resched) {
+ if (spin_needbreak(lock) || resched || need_rcu_resched) {
spin_unlock(lock);
if (resched)
__cond_resched();
+ else if (unlikely(need_rcu_resched))
+ rcu_resched();
else
cpu_relax();
ret = 1;
@@ -4091,6 +4095,7 @@ int __sched __cond_resched_softirq(void)
{
BUG_ON(!in_softirq());
+ rcu_cond_resched(); /* BH disabled OK, just recording QSes. */
if (should_resched()) {
local_bh_enable();
__cond_resched();
diff --git a/kernel/softirq.c b/kernel/softirq.c
index 92f24f5..5918d22 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -232,7 +232,6 @@ asmlinkage __visible void __do_softirq(void)
bool in_hardirq;
__u32 pending;
int softirq_bit;
- int cpu;
/*
* Mask out PF_MEMALLOC s current task context is borrowed for the
@@ -247,7 +246,6 @@ asmlinkage __visible void __do_softirq(void)
__local_bh_disable_ip(_RET_IP_, SOFTIRQ_OFFSET);
in_hardirq = lockdep_softirq_start();
- cpu = smp_processor_id();
restart:
/* Reset the pending bitmask before enabling irqs */
set_softirq_pending(0);
@@ -276,11 +274,11 @@ restart:
prev_count, preempt_count());
preempt_count_set(prev_count);
}
- rcu_bh_qs(cpu);
h++;
pending >>= softirq_bit;
}
+ rcu_bh_qs(smp_processor_id());
local_irq_disable();
pending = local_softirq_pending();
diff --git a/kernel/torture.c b/kernel/torture.c
index acc9afc..40bb511 100644
--- a/kernel/torture.c
+++ b/kernel/torture.c
@@ -335,13 +335,8 @@ static void torture_shuffle_tasks(void)
shuffle_idle_cpu = cpumask_next(shuffle_idle_cpu, shuffle_tmp_mask);
if (shuffle_idle_cpu >= nr_cpu_ids)
shuffle_idle_cpu = -1;
- if (shuffle_idle_cpu != -1) {
+ else
cpumask_clear_cpu(shuffle_idle_cpu, shuffle_tmp_mask);
- if (cpumask_empty(shuffle_tmp_mask)) {
- put_online_cpus();
- return;
- }
- }
mutex_lock(&shuffle_task_mutex);
list_for_each_entry(stp, &shuffle_task_list, st_l)
@@ -533,7 +528,11 @@ void stutter_wait(const char *title)
while (ACCESS_ONCE(stutter_pause_test) ||
(torture_runnable && !ACCESS_ONCE(*torture_runnable))) {
if (stutter_pause_test)
- schedule_timeout_interruptible(1);
+ if (ACCESS_ONCE(stutter_pause_test) == 1)
+ schedule_timeout_interruptible(1);
+ else
+ while (ACCESS_ONCE(stutter_pause_test))
+ cond_resched();
else
schedule_timeout_interruptible(round_jiffies_relative(HZ));
torture_shutdown_absorb(title);
@@ -550,7 +549,11 @@ static int torture_stutter(void *arg)
VERBOSE_TOROUT_STRING("torture_stutter task started");
do {
if (!torture_must_stop()) {
- schedule_timeout_interruptible(stutter);
+ if (stutter > 1) {
+ schedule_timeout_interruptible(stutter - 1);
+ ACCESS_ONCE(stutter_pause_test) = 2;
+ }
+ schedule_timeout_interruptible(1);
ACCESS_ONCE(stutter_pause_test) = 1;
}
if (!torture_must_stop())
@@ -596,21 +599,27 @@ static void torture_stutter_cleanup(void)
* The runnable parameter points to a flag that controls whether or not
* the test is currently runnable. If there is no such flag, pass in NULL.
*/
-void __init torture_init_begin(char *ttype, bool v, int *runnable)
+bool torture_init_begin(char *ttype, bool v, int *runnable)
{
mutex_lock(&fullstop_mutex);
+ if (torture_type != NULL) {
+ pr_alert("torture_init_begin: refusing %s init: %s running",
+ ttype, torture_type);
+ mutex_unlock(&fullstop_mutex);
+ return false;
+ }
torture_type = ttype;
verbose = v;
torture_runnable = runnable;
fullstop = FULLSTOP_DONTSTOP;
-
+ return true;
}
EXPORT_SYMBOL_GPL(torture_init_begin);
/*
* Tell the torture module that initialization is complete.
*/
-void __init torture_init_end(void)
+void torture_init_end(void)
{
mutex_unlock(&fullstop_mutex);
register_reboot_notifier(&torture_shutdown_nb);
@@ -642,6 +651,9 @@ bool torture_cleanup(void)
torture_shuffle_cleanup();
torture_stutter_cleanup();
torture_onoff_cleanup();
+ mutex_lock(&fullstop_mutex);
+ torture_type = NULL;
+ mutex_unlock(&fullstop_mutex);
return false;
}
EXPORT_SYMBOL_GPL(torture_cleanup);
@@ -674,8 +686,10 @@ EXPORT_SYMBOL_GPL(torture_must_stop_irq);
*/
void torture_kthread_stopping(char *title)
{
- if (verbose)
- VERBOSE_TOROUT_STRING(title);
+ char buf[128];
+
+ snprintf(buf, sizeof(buf), "Stopping %s", title);
+ VERBOSE_TOROUT_STRING(buf);
while (!kthread_should_stop()) {
torture_shutdown_absorb(title);
schedule_timeout_uninterruptible(1);
diff --git a/tools/testing/selftests/rcutorture/bin/configinit.sh b/tools/testing/selftests/rcutorture/bin/configinit.sh
index a1be6e6..9c3f3d3 100755
--- a/tools/testing/selftests/rcutorture/bin/configinit.sh
+++ b/tools/testing/selftests/rcutorture/bin/configinit.sh
@@ -62,7 +62,7 @@ grep '^grep' < $T/u.sh > $T/upd.sh
echo "cat - $c" >> $T/upd.sh
make mrproper
make $buildloc distclean > $builddir/Make.distclean 2>&1
-make $buildloc defconfig > $builddir/Make.defconfig.out 2>&1
+make $buildloc $TORTURE_DEFCONFIG > $builddir/Make.defconfig.out 2>&1
mv $builddir/.config $builddir/.config.sav
sh $T/upd.sh < $builddir/.config.sav > $builddir/.config
cp $builddir/.config $builddir/.config.new
diff --git a/tools/testing/selftests/rcutorture/bin/functions.sh b/tools/testing/selftests/rcutorture/bin/functions.sh
index 9b17e81..d01b865 100644
--- a/tools/testing/selftests/rcutorture/bin/functions.sh
+++ b/tools/testing/selftests/rcutorture/bin/functions.sh
@@ -76,15 +76,39 @@ configfrag_hotplug_cpu () {
grep -q '^CONFIG_HOTPLUG_CPU=y$' "$1"
}
+# identify_boot_image qemu-cmd
+#
+# Returns the relative path to the kernel build image. This will be
+# arch/<arch>/boot/bzImage unless overridden with the TORTURE_BOOT_IMAGE
+# environment variable.
+identify_boot_image () {
+ if test -n "$TORTURE_BOOT_IMAGE"
+ then
+ echo $TORTURE_BOOT_IMAGE
+ else
+ case "$1" in
+ qemu-system-x86_64|qemu-system-i386)
+ echo arch/x86/boot/bzImage
+ ;;
+ qemu-system-ppc64)
+ echo arch/powerpc/boot/bzImage
+ ;;
+ *)
+ echo ""
+ ;;
+ esac
+ fi
+}
+
# identify_qemu builddir
#
# Returns our best guess as to which qemu command is appropriate for
-# the kernel at hand. Override with the RCU_QEMU_CMD environment variable.
+# the kernel at hand. Override with the TORTURE_QEMU_CMD environment variable.
identify_qemu () {
local u="`file "$1"`"
- if test -n "$RCU_QEMU_CMD"
+ if test -n "$TORTURE_QEMU_CMD"
then
- echo $RCU_QEMU_CMD
+ echo $TORTURE_QEMU_CMD
elif echo $u | grep -q x86-64
then
echo qemu-system-x86_64
@@ -98,7 +122,7 @@ identify_qemu () {
echo Cannot figure out what qemu command to use! 1>&2
echo file $1 output: $u
# Usually this will be one of /usr/bin/qemu-system-*
- # Use RCU_QEMU_CMD environment variable or appropriate
+ # Use TORTURE_QEMU_CMD environment variable or appropriate
# argument to top-level script.
exit 1
fi
@@ -107,14 +131,14 @@ identify_qemu () {
# identify_qemu_append qemu-cmd
#
# Output arguments for the qemu "-append" string based on CPU type
-# and the RCU_QEMU_INTERACTIVE environment variable.
+# and the TORTURE_QEMU_INTERACTIVE environment variable.
identify_qemu_append () {
case "$1" in
qemu-system-x86_64|qemu-system-i386)
echo noapic selinux=0 initcall_debug debug
;;
esac
- if test -n "$RCU_QEMU_INTERACTIVE"
+ if test -n "$TORTURE_QEMU_INTERACTIVE"
then
echo root=/dev/sda
else
@@ -124,8 +148,8 @@ identify_qemu_append () {
# identify_qemu_args qemu-cmd serial-file
#
-# Output arguments for qemu arguments based on the RCU_QEMU_MAC
-# and RCU_QEMU_INTERACTIVE environment variables.
+# Output arguments for qemu arguments based on the TORTURE_QEMU_MAC
+# and TORTURE_QEMU_INTERACTIVE environment variables.
identify_qemu_args () {
case "$1" in
qemu-system-x86_64|qemu-system-i386)
@@ -133,17 +157,17 @@ identify_qemu_args () {
qemu-system-ppc64)
echo -enable-kvm -M pseries -cpu POWER7 -nodefaults
echo -device spapr-vscsi
- if test -n "$RCU_QEMU_INTERACTIVE" -a -n "$RCU_QEMU_MAC"
+ if test -n "$TORTURE_QEMU_INTERACTIVE" -a -n "$TORTURE_QEMU_MAC"
then
- echo -device spapr-vlan,netdev=net0,mac=$RCU_QEMU_MAC
+ echo -device spapr-vlan,netdev=net0,mac=$TORTURE_QEMU_MAC
echo -netdev bridge,br=br0,id=net0
- elif test -n "$RCU_QEMU_INTERACTIVE"
+ elif test -n "$TORTURE_QEMU_INTERACTIVE"
then
echo -net nic -net user
fi
;;
esac
- if test -n "$RCU_QEMU_INTERACTIVE"
+ if test -n "$TORTURE_QEMU_INTERACTIVE"
then
echo -monitor stdio -serial pty -S
else
diff --git a/tools/testing/selftests/rcutorture/bin/kvm-build.sh b/tools/testing/selftests/rcutorture/bin/kvm-build.sh
index 197901e..7c1e56b 100755
--- a/tools/testing/selftests/rcutorture/bin/kvm-build.sh
+++ b/tools/testing/selftests/rcutorture/bin/kvm-build.sh
@@ -45,9 +45,9 @@ T=/tmp/test-linux.sh.$$
trap 'rm -rf $T' 0
mkdir $T
-cat ${config_template} | grep -v CONFIG_RCU_TORTURE_TEST > $T/config
+grep -v 'CONFIG_[A-Z]*_TORTURE_TEST' < ${config_template} > $T/config
cat << ___EOF___ >> $T/config
-CONFIG_INITRAMFS_SOURCE="$RCU_INITRD"
+CONFIG_INITRAMFS_SOURCE="$TORTURE_INITRD"
CONFIG_VIRTIO_PCI=y
CONFIG_VIRTIO_CONSOLE=y
___EOF___
@@ -60,7 +60,7 @@ then
exit 2
fi
ncpus=`cpus2use.sh`
-make O=$builddir -j$ncpus $RCU_KMAKE_ARG > $builddir/Make.out 2>&1
+make O=$builddir -j$ncpus $TORTURE_KMAKE_ARG > $builddir/Make.out 2>&1
retval=$?
if test $retval -ne 0 || grep "rcu[^/]*": < $builddir/Make.out | egrep -q "Stop|Error|error:|warning:" || egrep -q "Stop|Error|error:" < $builddir/Make.out
then
diff --git a/tools/testing/selftests/rcutorture/bin/kvm-recheck-lock.sh b/tools/testing/selftests/rcutorture/bin/kvm-recheck-lock.sh
index 829186e..7f1ff1a 100755
--- a/tools/testing/selftests/rcutorture/bin/kvm-recheck-lock.sh
+++ b/tools/testing/selftests/rcutorture/bin/kvm-recheck-lock.sh
@@ -35,7 +35,7 @@ configfile=`echo $i | sed -e 's/^.*\///'`
ncs=`grep "Writes: Total:" $i/console.log 2> /dev/null | tail -1 | sed -e 's/^.* Total: //' -e 's/ .*$//'`
if test -z "$ncs"
then
- echo $configfile
+ echo "$configfile -------"
else
title="$configfile ------- $ncs acquisitions/releases"
dur=`sed -e 's/^.* locktorture.shutdown_secs=//' -e 's/ .*$//' < $i/qemu-cmd 2> /dev/null`
diff --git a/tools/testing/selftests/rcutorture/bin/kvm-recheck-rcu.sh b/tools/testing/selftests/rcutorture/bin/kvm-recheck-rcu.sh
index d75b1dc5..307c4b9 100755
--- a/tools/testing/selftests/rcutorture/bin/kvm-recheck-rcu.sh
+++ b/tools/testing/selftests/rcutorture/bin/kvm-recheck-rcu.sh
@@ -35,7 +35,7 @@ configfile=`echo $i | sed -e 's/^.*\///'`
ngps=`grep ver: $i/console.log 2> /dev/null | tail -1 | sed -e 's/^.* ver: //' -e 's/ .*$//'`
if test -z "$ngps"
then
- echo $configfile
+ echo "$configfile -------"
else
title="$configfile ------- $ngps grace periods"
dur=`sed -e 's/^.* rcutorture.shutdown_secs=//' -e 's/ .*$//' < $i/qemu-cmd 2> /dev/null`
diff --git a/tools/testing/selftests/rcutorture/bin/kvm-recheck.sh b/tools/testing/selftests/rcutorture/bin/kvm-recheck.sh
index a44daaa..ee1f6ca 100755
--- a/tools/testing/selftests/rcutorture/bin/kvm-recheck.sh
+++ b/tools/testing/selftests/rcutorture/bin/kvm-recheck.sh
@@ -25,6 +25,7 @@
# Authors: Paul E. McKenney <paulmck@...ux.vnet.ibm.com>
PATH=`pwd`/tools/testing/selftests/rcutorture/bin:$PATH; export PATH
+. tools/testing/selftests/rcutorture/bin/functions.sh
for rd in "$@"
do
firsttime=1
@@ -39,13 +40,24 @@ do
fi
TORTURE_SUITE="`cat $i/../TORTURE_SUITE`"
kvm-recheck-${TORTURE_SUITE}.sh $i
- configcheck.sh $i/.config $i/ConfigFragment
- parse-build.sh $i/Make.out $configfile
- parse-rcutorture.sh $i/console.log $configfile
- parse-console.sh $i/console.log $configfile
- if test -r $i/Warnings
+ if test -f "$i/console.log"
then
- cat $i/Warnings
+ configcheck.sh $i/.config $i/ConfigFragment
+ parse-build.sh $i/Make.out $configfile
+ parse-torture.sh $i/console.log $configfile
+ parse-console.sh $i/console.log $configfile
+ if test -r $i/Warnings
+ then
+ cat $i/Warnings
+ fi
+ else
+ if test -f "$i/qemu-cmd"
+ then
+ print_bug qemu failed
+ else
+ print_bug Build failed
+ fi
+ echo " $i"
fi
done
done
diff --git a/tools/testing/selftests/rcutorture/bin/kvm-test-1-run.sh b/tools/testing/selftests/rcutorture/bin/kvm-test-1-run.sh
index 94b28bb..27e544e 100755
--- a/tools/testing/selftests/rcutorture/bin/kvm-test-1-run.sh
+++ b/tools/testing/selftests/rcutorture/bin/kvm-test-1-run.sh
@@ -94,9 +94,17 @@ fi
# CONFIG_YENTA=n
if kvm-build.sh $config_template $builddir $T
then
+ QEMU="`identify_qemu $builddir/vmlinux`"
+ BOOT_IMAGE="`identify_boot_image $QEMU`"
cp $builddir/Make*.out $resdir
cp $builddir/.config $resdir
- cp $builddir/arch/x86/boot/bzImage $resdir
+ if test -n "$BOOT_IMAGE"
+ then
+ cp $builddir/$BOOT_IMAGE $resdir
+ else
+ echo No identifiable boot image, not running KVM, see $resdir.
+ echo Do the torture scripts know about your architecture?
+ fi
parse-build.sh $resdir/Make.out $title
if test -f $builddir.wait
then
@@ -104,6 +112,7 @@ then
fi
else
cp $builddir/Make*.out $resdir
+ cp $builddir/.config $resdir || :
echo Build failed, not running KVM, see $resdir.
if test -f $builddir.wait
then
@@ -124,9 +133,6 @@ cd $KVM
kstarttime=`awk 'BEGIN { print systime() }' < /dev/null`
echo ' ---' `date`: Starting kernel
-# Determine the appropriate flavor of qemu command.
-QEMU="`identify_qemu $builddir/vmlinux`"
-
# Generate -smp qemu argument.
qemu_args="-nographic $qemu_args"
cpu_count=`configNR_CPUS.sh $config_template`
@@ -151,27 +157,38 @@ boot_args="`configfrag_boot_params "$boot_args" "$config_template"`"
# Generate kernel-version-specific boot parameters
boot_args="`per_version_boot_params "$boot_args" $builddir/.config $seconds`"
-echo $QEMU $qemu_args -m 512 -kernel $builddir/arch/x86/boot/bzImage -append \"$qemu_append $boot_args\" > $resdir/qemu-cmd
-if test -n "$RCU_BUILDONLY"
+echo $QEMU $qemu_args -m 512 -kernel $builddir/$BOOT_IMAGE -append \"$qemu_append $boot_args\" > $resdir/qemu-cmd
+if test -n "$TORTURE_BUILDONLY"
then
echo Build-only run specified, boot/test omitted.
exit 0
fi
-$QEMU $qemu_args -m 512 -kernel $builddir/arch/x86/boot/bzImage -append "$qemu_append $boot_args" &
+( $QEMU $qemu_args -m 512 -kernel $builddir/$BOOT_IMAGE -append "$qemu_append $boot_args"; echo $? > $resdir/qemu-retval ) &
qemu_pid=$!
commandcompleted=0
echo Monitoring qemu job at pid $qemu_pid
-for ((i=0;i<$seconds;i++))
+while :
do
+ kruntime=`awk 'BEGIN { print systime() - '"$kstarttime"' }' < /dev/null`
if kill -0 $qemu_pid > /dev/null 2>&1
then
+ if test $kruntime -ge $seconds
+ then
+ break;
+ fi
sleep 1
else
commandcompleted=1
- kruntime=`awk 'BEGIN { print systime() - '"$kstarttime"' }' < /dev/null`
if test $kruntime -lt $seconds
then
echo Completed in $kruntime vs. $seconds >> $resdir/Warnings 2>&1
+ grep "^(qemu) qemu:" $resdir/kvm-test-1-run.sh.out >> $resdir/Warnings 2>&1
+ killpid="`sed -n "s/^(qemu) qemu: terminating on signal [0-9]* from pid \([0-9]*\).*$/\1/p" $resdir/Warnings`"
+ if test -n "$killpid"
+ then
+ echo "ps -fp $killpid" >> $resdir/Warnings 2>&1
+ ps -fp $killpid >> $resdir/Warnings 2>&1
+ fi
else
echo ' ---' `date`: Kernel done
fi
@@ -181,23 +198,25 @@ done
if test $commandcompleted -eq 0
then
echo Grace period for qemu job at pid $qemu_pid
- for ((i=0;i<=$grace;i++))
+ while :
do
+ kruntime=`awk 'BEGIN { print systime() - '"$kstarttime"' }' < /dev/null`
if kill -0 $qemu_pid > /dev/null 2>&1
then
- sleep 1
+ :
else
break
fi
- if test $i -eq $grace
+ if test $kruntime -ge $((seconds + grace))
then
- kruntime=`awk 'BEGIN { print systime() - '"$kstarttime"' }'`
echo "!!! Hang at $kruntime vs. $seconds seconds" >> $resdir/Warnings 2>&1
kill -KILL $qemu_pid
+ break
fi
+ sleep 1
done
fi
cp $builddir/console.log $resdir
-parse-${TORTURE_SUITE}torture.sh $resdir/console.log $title
+parse-torture.sh $resdir/console.log $title
parse-console.sh $resdir/console.log $title
diff --git a/tools/testing/selftests/rcutorture/bin/kvm.sh b/tools/testing/selftests/rcutorture/bin/kvm.sh
index 5a78cbf..40285c5 100644
--- a/tools/testing/selftests/rcutorture/bin/kvm.sh
+++ b/tools/testing/selftests/rcutorture/bin/kvm.sh
@@ -38,9 +38,10 @@ dur=30
dryrun=""
KVM="`pwd`/tools/testing/selftests/rcutorture"; export KVM
PATH=${KVM}/bin:$PATH; export PATH
-builddir="${KVM}/b1"
-RCU_INITRD="$KVM/initrd"; export RCU_INITRD
-RCU_KMAKE_ARG=""; export RCU_KMAKE_ARG
+TORTURE_DEFCONFIG=defconfig
+TORTURE_BOOT_IMAGE=""
+TORTURE_INITRD="$KVM/initrd"; export TORTURE_INITRD
+TORTURE_KMAKE_ARG=""
TORTURE_SUITE=rcu
resdir=""
configs=""
@@ -53,11 +54,12 @@ kversion=""
usage () {
echo "Usage: $scriptname optional arguments:"
echo " --bootargs kernel-boot-arguments"
- echo " --builddir absolute-pathname"
+ echo " --bootimage relative-path-to-kernel-boot-image"
echo " --buildonly"
echo " --configs \"config-file list\""
echo " --cpus N"
echo " --datestamp string"
+ echo " --defconfig string"
echo " --dryrun sched|script"
echo " --duration minutes"
echo " --interactive"
@@ -67,7 +69,6 @@ usage () {
echo " --no-initrd"
echo " --qemu-args qemu-system-..."
echo " --qemu-cmd qemu-system-..."
- echo " --relbuilddir relative-pathname"
echo " --results absolute-pathname"
echo " --torture rcu"
exit 1
@@ -78,17 +79,16 @@ do
case "$1" in
--bootargs)
checkarg --bootargs "(list of kernel boot arguments)" "$#" "$2" '.*' '^--'
- RCU_BOOTARGS="$2"
+ TORTURE_BOOTARGS="$2"
shift
;;
- --builddir)
- checkarg --builddir "(absolute pathname)" "$#" "$2" '^/' '^error'
- builddir=$2
- gotbuilddir=1
+ --bootimage)
+ checkarg --bootimage "(relative path to kernel boot image)" "$#" "$2" '[a-zA-Z0-9][a-zA-Z0-9_]*' '^--'
+ TORTURE_BOOT_IMAGE="$2"
shift
;;
--buildonly)
- RCU_BUILDONLY=1; export RCU_BUILDONLY
+ TORTURE_BUILDONLY=1
;;
--configs)
checkarg --configs "(list of config files)" "$#" "$2" '^[^/]*$' '^--'
@@ -105,6 +105,11 @@ do
ds=$2
shift
;;
+ --defconfig)
+ checkarg --defconfig "defconfigtype" "$#" "$2" '^[^/][^/]*$' '^--'
+ TORTURE_DEFCONFIG=$2
+ shift
+ ;;
--dryrun)
checkarg --dryrun "sched|script" $# "$2" 'sched\|script' '^--'
dryrun=$2
@@ -116,11 +121,11 @@ do
shift
;;
--interactive)
- RCU_QEMU_INTERACTIVE=1; export RCU_QEMU_INTERACTIVE
+ TORTURE_QEMU_INTERACTIVE=1; export TORTURE_QEMU_INTERACTIVE
;;
--kmake-arg)
checkarg --kmake-arg "(kernel make arguments)" $# "$2" '.*' '^error$'
- RCU_KMAKE_ARG="$2"; export RCU_KMAKE_ARG
+ TORTURE_KMAKE_ARG="$2"
shift
;;
--kversion)
@@ -130,27 +135,20 @@ do
;;
--mac)
checkarg --mac "(MAC address)" $# "$2" '^\([0-9a-fA-F]\{2\}:\)\{5\}[0-9a-fA-F]\{2\}$' error
- RCU_QEMU_MAC=$2; export RCU_QEMU_MAC
+ TORTURE_QEMU_MAC=$2
shift
;;
--no-initrd)
- RCU_INITRD=""; export RCU_INITRD
+ TORTURE_INITRD=""; export TORTURE_INITRD
;;
--qemu-args)
checkarg --qemu-args "-qemu args" $# "$2" '^-' '^error'
- RCU_QEMU_ARG="$2"
+ TORTURE_QEMU_ARG="$2"
shift
;;
--qemu-cmd)
checkarg --qemu-cmd "(qemu-system-...)" $# "$2" 'qemu-system-' '^--'
- RCU_QEMU_CMD="$2"; export RCU_QEMU_CMD
- shift
- ;;
- --relbuilddir)
- checkarg --relbuilddir "(relative pathname)" "$#" "$2" '^[^/]*$' '^--'
- relbuilddir=$2
- gotrelbuilddir=1
- builddir=${KVM}/${relbuilddir}
+ TORTURE_QEMU_CMD="$2"
shift
;;
--results)
@@ -184,30 +182,6 @@ then
resdir=$KVM/res
fi
-if test "$dryrun" = ""
-then
- if ! test -e $resdir
- then
- mkdir -p "$resdir" || :
- fi
- mkdir $resdir/$ds
-
- # Be noisy only if running the script.
- echo Results directory: $resdir/$ds
- echo $scriptname $args
-
- touch $resdir/$ds/log
- echo $scriptname $args >> $resdir/$ds/log
- echo ${TORTURE_SUITE} > $resdir/$ds/TORTURE_SUITE
-
- pwd > $resdir/$ds/testid.txt
- if test -d .git
- then
- git status >> $resdir/$ds/testid.txt
- git rev-parse HEAD >> $resdir/$ds/testid.txt
- fi
-fi
-
# Create a file of test-name/#cpus pairs, sorted by decreasing #cpus.
touch $T/cfgcpu
for CF in $configs
@@ -274,7 +248,39 @@ END {
# Generate a script to execute the tests in appropriate batches.
cat << ___EOF___ > $T/script
+CONFIGFRAG="$CONFIGFRAG"; export CONFIGFRAG
+KVM="$KVM"; export KVM
+KVPATH="$KVPATH"; export KVPATH
+PATH="$PATH"; export PATH
+TORTURE_BOOT_IMAGE="$TORTURE_BOOT_IMAGE"; export TORTURE_BOOT_IMAGE
+TORTURE_BUILDONLY="$TORTURE_BUILDONLY"; export TORTURE_BUILDONLY
+TORTURE_DEFCONFIG="$TORTURE_DEFCONFIG"; export TORTURE_DEFCONFIG
+TORTURE_INITRD="$TORTURE_INITRD"; export TORTURE_INITRD
+TORTURE_KMAKE_ARG="$TORTURE_KMAKE_ARG"; export TORTURE_KMAKE_ARG
+TORTURE_QEMU_CMD="$TORTURE_QEMU_CMD"; export TORTURE_QEMU_CMD
+TORTURE_QEMU_INTERACTIVE="$TORTURE_QEMU_INTERACTIVE"; export TORTURE_QEMU_INTERACTIVE
+TORTURE_QEMU_MAC="$TORTURE_QEMU_MAC"; export TORTURE_QEMU_MAC
TORTURE_SUITE="$TORTURE_SUITE"; export TORTURE_SUITE
+if ! test -e $resdir
+then
+ mkdir -p "$resdir" || :
+fi
+mkdir $resdir/$ds
+echo Results directory: $resdir/$ds
+echo $scriptname $args
+touch $resdir/$ds/log
+echo $scriptname $args >> $resdir/$ds/log
+echo ${TORTURE_SUITE} > $resdir/$ds/TORTURE_SUITE
+pwd > $resdir/$ds/testid.txt
+if test -d .git
+then
+ git status >> $resdir/$ds/testid.txt
+ git rev-parse HEAD >> $resdir/$ds/testid.txt
+ if ! git diff HEAD > $T/git-diff 2>&1
+ then
+ cp $T/git-diff $resdir/$ds
+ fi
+fi
___EOF___
awk < $T/cfgcpu.pack \
-v CONFIGDIR="$CONFIGFRAG/$kversion/" \
@@ -282,8 +288,8 @@ awk < $T/cfgcpu.pack \
-v ncpus=$cpus \
-v rd=$resdir/$ds/ \
-v dur=$dur \
- -v RCU_QEMU_ARG=$RCU_QEMU_ARG \
- -v RCU_BOOTARGS=$RCU_BOOTARGS \
+ -v TORTURE_QEMU_ARG="$TORTURE_QEMU_ARG" \
+ -v TORTURE_BOOTARGS="$TORTURE_BOOTARGS" \
'BEGIN {
i = 0;
}
@@ -320,7 +326,7 @@ function dump(first, pastlast)
print "touch " builddir ".wait";
print "mkdir " builddir " > /dev/null 2>&1 || :";
print "mkdir " rd cfr[jn] " || :";
- print "kvm-test-1-run.sh " CONFIGDIR cf[j], builddir, rd cfr[jn], dur " \"" RCU_QEMU_ARG "\" \"" RCU_BOOTARGS "\" > " rd cfr[jn] "/kvm-test-1-run.sh.out 2>&1 &"
+ print "kvm-test-1-run.sh " CONFIGDIR cf[j], builddir, rd cfr[jn], dur " \"" TORTURE_QEMU_ARG "\" \"" TORTURE_BOOTARGS "\" > " rd cfr[jn] "/kvm-test-1-run.sh.out 2>&1 &"
print "echo ", cfr[jn], cpusr[jn] ovf ": Waiting for build to complete. `date`";
print "echo ", cfr[jn], cpusr[jn] ovf ": Waiting for build to complete. `date` >> " rd "/log";
print "while test -f " builddir ".wait"
@@ -374,28 +380,26 @@ END {
dump(first, i);
}' >> $T/script
+cat << ___EOF___ >> $T/script
+echo
+echo
+echo " --- `date` Test summary:"
+echo Results directory: $resdir/$ds
+if test -z "$TORTURE_BUILDONLY"
+then
+ kvm-recheck.sh $resdir/$ds
+fi
+___EOF___
+
if test "$dryrun" = script
then
- # Dump out the script, but define the environment variables that
- # it needs to run standalone.
- echo CONFIGFRAG="$CONFIGFRAG; export CONFIGFRAG"
- echo KVM="$KVM; export KVM"
- echo KVPATH="$KVPATH; export KVPATH"
- echo PATH="$PATH; export PATH"
- echo RCU_BUILDONLY="$RCU_BUILDONLY; export RCU_BUILDONLY"
- echo RCU_INITRD="$RCU_INITRD; export RCU_INITRD"
- echo RCU_KMAKE_ARG="$RCU_KMAKE_ARG; export RCU_KMAKE_ARG"
- echo RCU_QEMU_CMD="$RCU_QEMU_CMD; export RCU_QEMU_CMD"
- echo RCU_QEMU_INTERACTIVE="$RCU_QEMU_INTERACTIVE; export RCU_QEMU_INTERACTIVE"
- echo RCU_QEMU_MAC="$RCU_QEMU_MAC; export RCU_QEMU_MAC"
- echo "mkdir -p "$resdir" || :"
- echo "mkdir $resdir/$ds"
cat $T/script
exit 0
elif test "$dryrun" = sched
then
# Extract the test run schedule from the script.
- egrep 'start batch|Starting build\.' $T/script |
+ egrep 'Start batch|Starting build\.' $T/script |
+ grep -v ">>" |
sed -e 's/:.*$//' -e 's/^echo //'
exit 0
else
@@ -404,9 +408,3 @@ else
fi
# Tracing: trace_event=rcu:rcu_grace_period,rcu:rcu_future_grace_period,rcu:rcu_grace_period_init,rcu:rcu_nocb_wake,rcu:rcu_preempt_task,rcu:rcu_unlock_preempted_task,rcu:rcu_quiescent_state_report,rcu:rcu_fqs,rcu:rcu_callback,rcu:rcu_kfree_callback,rcu:rcu_batch_start,rcu:rcu_invoke_callback,rcu:rcu_invoke_kfree_callback,rcu:rcu_batch_end,rcu:rcu_torture_read,rcu:rcu_barrier
-
-echo
-echo
-echo " --- `date` Test summary:"
-echo Results directory: $resdir/$ds
-kvm-recheck.sh $resdir/$ds
diff --git a/tools/testing/selftests/rcutorture/bin/parse-rcutorture.sh b/tools/testing/selftests/rcutorture/bin/parse-torture.sh
similarity index 79%
rename from tools/testing/selftests/rcutorture/bin/parse-rcutorture.sh
rename to tools/testing/selftests/rcutorture/bin/parse-torture.sh
index dd0a275..3455560 100755
--- a/tools/testing/selftests/rcutorture/bin/parse-rcutorture.sh
+++ b/tools/testing/selftests/rcutorture/bin/parse-torture.sh
@@ -1,14 +1,14 @@
#!/bin/sh
#
-# Check the console output from an rcutorture run for goodness.
+# Check the console output from a torture run for goodness.
# The "file" is a pathname on the local system, and "title" is
# a text string for error-message purposes.
#
-# The file must contain rcutorture output, but can be interspersed
-# with other dmesg text.
+# The file must contain torture output, but can be interspersed
+# with other dmesg text, as in console-log output.
#
# Usage:
-# sh parse-rcutorture.sh file title
+# sh parse-torture.sh file title
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
@@ -28,7 +28,7 @@
#
# Authors: Paul E. McKenney <paulmck@...ux.vnet.ibm.com>
-T=/tmp/parse-rcutorture.sh.$$
+T=/tmp/parse-torture.sh.$$
file="$1"
title="$2"
@@ -36,13 +36,13 @@ trap 'rm -f $T.seq' 0
. functions.sh
-# check for presence of rcutorture.txt file
+# check for presence of torture output file.
if test -f "$file" -a -r "$file"
then
:
else
- echo $title unreadable rcutorture.txt file: $file
+ echo $title unreadable torture output file: $file
exit 1
fi
@@ -76,9 +76,9 @@ BEGIN {
END {
if (badseq) {
if (badseqno1 == badseqno2 && badseqno2 == ver)
- print "RCU GP HANG at " ver " rcutorture stat " badseqnr;
+ print "GP HANG at " ver " torture stat " badseqnr;
else
- print "BAD SEQ " badseqno1 ":" badseqno2 " last:" ver " RCU version " badseqnr;
+ print "BAD SEQ " badseqno1 ":" badseqno2 " last:" ver " version " badseqnr;
}
}' > $T.seq
@@ -91,13 +91,13 @@ then
exit 2
fi
else
- if grep -q RCU_HOTPLUG $file
+ if grep -q "_HOTPLUG:" $file
then
print_warning HOTPLUG FAILURES $title `cat $T.seq`
echo " " $file
exit 3
fi
- echo $title no success message, `grep --binary-files=text 'ver:' $file | wc -l` successful RCU version messages
+ echo $title no success message, `grep --binary-files=text 'ver:' $file | wc -l` successful version messages
if test -s $T.seq
then
print_warning $title `cat $T.seq`
diff --git a/tools/testing/selftests/rcutorture/configs/rcu/TREE02-T b/tools/testing/selftests/rcutorture/configs/rcu/TREE02-T
new file mode 100644
index 0000000..61c8d9c
--- /dev/null
+++ b/tools/testing/selftests/rcutorture/configs/rcu/TREE02-T
@@ -0,0 +1,25 @@
+CONFIG_SMP=y
+CONFIG_NR_CPUS=8
+CONFIG_PREEMPT_NONE=n
+CONFIG_PREEMPT_VOLUNTARY=n
+CONFIG_PREEMPT=y
+#CHECK#CONFIG_TREE_PREEMPT_RCU=y
+CONFIG_HZ_PERIODIC=n
+CONFIG_NO_HZ_IDLE=y
+CONFIG_NO_HZ_FULL=n
+CONFIG_RCU_FAST_NO_HZ=n
+CONFIG_RCU_TRACE=y
+CONFIG_HOTPLUG_CPU=n
+CONFIG_SUSPEND=n
+CONFIG_HIBERNATION=n
+CONFIG_RCU_FANOUT=3
+CONFIG_RCU_FANOUT_LEAF=3
+CONFIG_RCU_FANOUT_EXACT=n
+CONFIG_RCU_NOCB_CPU=n
+CONFIG_DEBUG_LOCK_ALLOC=y
+CONFIG_PROVE_LOCKING=n
+CONFIG_PROVE_RCU_DELAY=n
+CONFIG_RCU_CPU_STALL_INFO=n
+CONFIG_RCU_CPU_STALL_VERBOSE=y
+CONFIG_RCU_BOOST=n
+CONFIG_DEBUG_OBJECTS_RCU_HEAD=n
diff --git a/tools/testing/selftests/rcutorture/configs/rcu/TREE08.boot b/tools/testing/selftests/rcutorture/configs/rcu/TREE08.boot
new file mode 100644
index 0000000..3b42b8b
--- /dev/null
+++ b/tools/testing/selftests/rcutorture/configs/rcu/TREE08.boot
@@ -0,0 +1 @@
+rcutorture.torture_type=sched
--
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