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Date: Fri, 17 Jul 2015 16:29:07 -0700
From: "Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>
To: linux-kernel@...r.kernel.org
Cc: mingo@...nel.org, jiangshanlai@...il.com, dipankar@...ibm.com,
akpm@...ux-foundation.org, mathieu.desnoyers@...icios.com,
josh@...htriplett.org, tglx@...utronix.de, peterz@...radead.org,
rostedt@...dmis.org, dhowells@...hat.com, edumazet@...gle.com,
dvhart@...ux.intel.com, fweisbec@...il.com, oleg@...hat.com,
bobby.prani@...il.com,
"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>
Subject: [PATCH tip/core/rcu 02/19] rcu: Remove CONFIG_RCU_CPU_STALL_INFO
From: "Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>
The CONFIG_RCU_CPU_STALL_INFO has been default-y for a couple of
releases with no complaints, so it is time to eliminate this Kconfig
option entirely, so that the long-form RCU CPU stall warnings cannot
be disabled. This commit does just that.
Signed-off-by: Paul E. McKenney <paulmck@...ux.vnet.ibm.com>
---
Documentation/RCU/stallwarn.txt | 12 +-----
kernel/rcu/tree.h | 4 --
kernel/rcu/tree_plugin.h | 45 ----------------------
lib/Kconfig.debug | 14 -------
.../selftests/rcutorture/configs/rcu/TREE01 | 1 -
.../selftests/rcutorture/configs/rcu/TREE02 | 1 -
.../selftests/rcutorture/configs/rcu/TREE02-T | 1 -
.../selftests/rcutorture/configs/rcu/TREE03 | 1 -
.../selftests/rcutorture/configs/rcu/TREE04 | 1 -
.../selftests/rcutorture/configs/rcu/TREE05 | 1 -
.../selftests/rcutorture/configs/rcu/TREE06 | 1 -
.../selftests/rcutorture/configs/rcu/TREE07 | 1 -
.../selftests/rcutorture/configs/rcu/TREE08 | 1 -
.../selftests/rcutorture/configs/rcu/TREE08-T | 1 -
.../selftests/rcutorture/configs/rcu/TREE09 | 1 -
.../selftests/rcutorture/doc/TREE_RCU-kconfig.txt | 1 -
16 files changed, 2 insertions(+), 85 deletions(-)
diff --git a/Documentation/RCU/stallwarn.txt b/Documentation/RCU/stallwarn.txt
index b57c0c1cdac6..046f32637b95 100644
--- a/Documentation/RCU/stallwarn.txt
+++ b/Documentation/RCU/stallwarn.txt
@@ -26,12 +26,6 @@ CONFIG_RCU_CPU_STALL_TIMEOUT
Stall-warning messages may be enabled and disabled completely via
/sys/module/rcupdate/parameters/rcu_cpu_stall_suppress.
-CONFIG_RCU_CPU_STALL_INFO
-
- This kernel configuration parameter causes the stall warning to
- print out additional per-CPU diagnostic information, including
- information on scheduling-clock ticks and RCU's idle-CPU tracking.
-
RCU_STALL_DELAY_DELTA
Although the lockdep facility is extremely useful, it does add
@@ -101,15 +95,13 @@ interact. Please note that it is not possible to entirely eliminate this
sort of false positive without resorting to things like stop_machine(),
which is overkill for this sort of problem.
-If the CONFIG_RCU_CPU_STALL_INFO kernel configuration parameter is set,
-more information is printed with the stall-warning message, for example:
+Recent kernels will print a long form of the stall-warning message:
INFO: rcu_preempt detected stall on CPU
0: (63959 ticks this GP) idle=241/3fffffffffffffff/0 softirq=82/543
(t=65000 jiffies)
-In kernels with CONFIG_RCU_FAST_NO_HZ, even more information is
-printed:
+In kernels with CONFIG_RCU_FAST_NO_HZ, more information is printed:
INFO: rcu_preempt detected stall on CPU
0: (64628 ticks this GP) idle=dd5/3fffffffffffffff/0 softirq=82/543 last_accelerate: a345/d342 nonlazy_posted: 25 .D
diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h
index faee5242d6ff..7c0b09d754a1 100644
--- a/kernel/rcu/tree.h
+++ b/kernel/rcu/tree.h
@@ -288,12 +288,10 @@ struct rcu_data {
bool gpwrap; /* Possible gpnum/completed wrap. */
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
unsigned long ticks_this_gp; /* The number of scheduling-clock */
/* ticks this CPU has handled */
/* during and after the last grace */
/* period it is aware of. */
-#endif /* #ifdef CONFIG_RCU_CPU_STALL_INFO */
/* 2) batch handling */
/*
@@ -388,9 +386,7 @@ struct rcu_data {
#endif /* #ifdef CONFIG_RCU_NOCB_CPU */
/* 8) RCU CPU stall data. */
-#ifdef CONFIG_RCU_CPU_STALL_INFO
unsigned int softirq_snap; /* Snapshot of softirq activity. */
-#endif /* #ifdef CONFIG_RCU_CPU_STALL_INFO */
int cpu;
struct rcu_state *rsp;
diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index 7234f03e0aa2..ef41c1b04ba6 100644
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -82,8 +82,6 @@ static void __init rcu_bootup_announce_oddness(void)
pr_info("\tRCU lockdep checking is enabled.\n");
if (IS_ENABLED(CONFIG_RCU_TORTURE_TEST_RUNNABLE))
pr_info("\tRCU torture testing starts during boot.\n");
- if (IS_ENABLED(CONFIG_RCU_CPU_STALL_INFO))
- pr_info("\tAdditional per-CPU info printed with stalls.\n");
if (RCU_NUM_LVLS >= 4)
pr_info("\tFour(or more)-level hierarchy is enabled.\n");
if (RCU_FANOUT_LEAF != 16)
@@ -418,8 +416,6 @@ static void rcu_print_detail_task_stall(struct rcu_state *rsp)
rcu_print_detail_task_stall_rnp(rnp);
}
-#ifdef CONFIG_RCU_CPU_STALL_INFO
-
static void rcu_print_task_stall_begin(struct rcu_node *rnp)
{
pr_err("\tTasks blocked on level-%d rcu_node (CPUs %d-%d):",
@@ -431,18 +427,6 @@ static void rcu_print_task_stall_end(void)
pr_cont("\n");
}
-#else /* #ifdef CONFIG_RCU_CPU_STALL_INFO */
-
-static void rcu_print_task_stall_begin(struct rcu_node *rnp)
-{
-}
-
-static void rcu_print_task_stall_end(void)
-{
-}
-
-#endif /* #else #ifdef CONFIG_RCU_CPU_STALL_INFO */
-
/*
* Scan the current list of tasks blocked within RCU read-side critical
* sections, printing out the tid of each.
@@ -1685,8 +1669,6 @@ early_initcall(rcu_register_oom_notifier);
#endif /* #else #if !defined(CONFIG_RCU_FAST_NO_HZ) */
-#ifdef CONFIG_RCU_CPU_STALL_INFO
-
#ifdef CONFIG_RCU_FAST_NO_HZ
static void print_cpu_stall_fast_no_hz(char *cp, int cpu)
@@ -1775,33 +1757,6 @@ static void increment_cpu_stall_ticks(void)
raw_cpu_inc(rsp->rda->ticks_this_gp);
}
-#else /* #ifdef CONFIG_RCU_CPU_STALL_INFO */
-
-static void print_cpu_stall_info_begin(void)
-{
- pr_cont(" {");
-}
-
-static void print_cpu_stall_info(struct rcu_state *rsp, int cpu)
-{
- pr_cont(" %d", cpu);
-}
-
-static void print_cpu_stall_info_end(void)
-{
- pr_cont("} ");
-}
-
-static void zero_cpu_stall_ticks(struct rcu_data *rdp)
-{
-}
-
-static void increment_cpu_stall_ticks(void)
-{
-}
-
-#endif /* #else #ifdef CONFIG_RCU_CPU_STALL_INFO */
-
#ifdef CONFIG_RCU_NOCB_CPU
/*
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index e2894b23efb6..8a34205d6922 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -1353,20 +1353,6 @@ config RCU_CPU_STALL_TIMEOUT
RCU grace period persists, additional CPU stall warnings are
printed at more widely spaced intervals.
-config RCU_CPU_STALL_INFO
- bool "Print additional diagnostics on RCU CPU stall"
- depends on (TREE_RCU || PREEMPT_RCU) && DEBUG_KERNEL
- default y
- help
- For each stalled CPU that is aware of the current RCU grace
- period, print out additional per-CPU diagnostic information
- regarding scheduling-clock ticks, idle state, and,
- for RCU_FAST_NO_HZ kernels, idle-entry state.
-
- Say N if you are unsure.
-
- Say Y if you want to enable such diagnostics.
-
config RCU_TRACE
bool "Enable tracing for RCU"
depends on DEBUG_KERNEL
diff --git a/tools/testing/selftests/rcutorture/configs/rcu/TREE01 b/tools/testing/selftests/rcutorture/configs/rcu/TREE01
index 8e9137f66831..f572b873c620 100644
--- a/tools/testing/selftests/rcutorture/configs/rcu/TREE01
+++ b/tools/testing/selftests/rcutorture/configs/rcu/TREE01
@@ -13,7 +13,6 @@ CONFIG_MAXSMP=y
CONFIG_RCU_NOCB_CPU=y
CONFIG_RCU_NOCB_CPU_ZERO=y
CONFIG_DEBUG_LOCK_ALLOC=n
-CONFIG_RCU_CPU_STALL_INFO=n
CONFIG_RCU_BOOST=n
CONFIG_DEBUG_OBJECTS_RCU_HEAD=n
CONFIG_RCU_EXPERT=y
diff --git a/tools/testing/selftests/rcutorture/configs/rcu/TREE02 b/tools/testing/selftests/rcutorture/configs/rcu/TREE02
index aeea6a204d14..ef6a22c44dea 100644
--- a/tools/testing/selftests/rcutorture/configs/rcu/TREE02
+++ b/tools/testing/selftests/rcutorture/configs/rcu/TREE02
@@ -17,7 +17,6 @@ CONFIG_RCU_FANOUT_LEAF=3
CONFIG_RCU_NOCB_CPU=n
CONFIG_DEBUG_LOCK_ALLOC=y
CONFIG_PROVE_LOCKING=n
-CONFIG_RCU_CPU_STALL_INFO=n
CONFIG_RCU_BOOST=n
CONFIG_DEBUG_OBJECTS_RCU_HEAD=n
CONFIG_RCU_EXPERT=y
diff --git a/tools/testing/selftests/rcutorture/configs/rcu/TREE02-T b/tools/testing/selftests/rcutorture/configs/rcu/TREE02-T
index 2ac9e68ea3d1..917d2517b5b5 100644
--- a/tools/testing/selftests/rcutorture/configs/rcu/TREE02-T
+++ b/tools/testing/selftests/rcutorture/configs/rcu/TREE02-T
@@ -17,6 +17,5 @@ CONFIG_RCU_FANOUT_LEAF=3
CONFIG_RCU_NOCB_CPU=n
CONFIG_DEBUG_LOCK_ALLOC=y
CONFIG_PROVE_LOCKING=n
-CONFIG_RCU_CPU_STALL_INFO=n
CONFIG_RCU_BOOST=n
CONFIG_DEBUG_OBJECTS_RCU_HEAD=n
diff --git a/tools/testing/selftests/rcutorture/configs/rcu/TREE03 b/tools/testing/selftests/rcutorture/configs/rcu/TREE03
index 72aa7d87ea99..7a17c503b382 100644
--- a/tools/testing/selftests/rcutorture/configs/rcu/TREE03
+++ b/tools/testing/selftests/rcutorture/configs/rcu/TREE03
@@ -13,7 +13,6 @@ CONFIG_RCU_FANOUT=2
CONFIG_RCU_FANOUT_LEAF=2
CONFIG_RCU_NOCB_CPU=n
CONFIG_DEBUG_LOCK_ALLOC=n
-CONFIG_RCU_CPU_STALL_INFO=n
CONFIG_RCU_BOOST=y
CONFIG_RCU_KTHREAD_PRIO=2
CONFIG_DEBUG_OBJECTS_RCU_HEAD=n
diff --git a/tools/testing/selftests/rcutorture/configs/rcu/TREE04 b/tools/testing/selftests/rcutorture/configs/rcu/TREE04
index 3f5112751cda..39a2c6d7d7ec 100644
--- a/tools/testing/selftests/rcutorture/configs/rcu/TREE04
+++ b/tools/testing/selftests/rcutorture/configs/rcu/TREE04
@@ -17,6 +17,5 @@ CONFIG_RCU_FANOUT=4
CONFIG_RCU_FANOUT_LEAF=4
CONFIG_RCU_NOCB_CPU=n
CONFIG_DEBUG_LOCK_ALLOC=n
-CONFIG_RCU_CPU_STALL_INFO=n
CONFIG_DEBUG_OBJECTS_RCU_HEAD=n
CONFIG_RCU_EXPERT=y
diff --git a/tools/testing/selftests/rcutorture/configs/rcu/TREE05 b/tools/testing/selftests/rcutorture/configs/rcu/TREE05
index c04dfea6fd21..1257d3227b1e 100644
--- a/tools/testing/selftests/rcutorture/configs/rcu/TREE05
+++ b/tools/testing/selftests/rcutorture/configs/rcu/TREE05
@@ -17,6 +17,5 @@ CONFIG_RCU_NOCB_CPU_NONE=y
CONFIG_DEBUG_LOCK_ALLOC=y
CONFIG_PROVE_LOCKING=y
#CHECK#CONFIG_PROVE_RCU=y
-CONFIG_RCU_CPU_STALL_INFO=n
CONFIG_DEBUG_OBJECTS_RCU_HEAD=n
CONFIG_RCU_EXPERT=y
diff --git a/tools/testing/selftests/rcutorture/configs/rcu/TREE06 b/tools/testing/selftests/rcutorture/configs/rcu/TREE06
index f51d2c73a68e..d3e456b74cbe 100644
--- a/tools/testing/selftests/rcutorture/configs/rcu/TREE06
+++ b/tools/testing/selftests/rcutorture/configs/rcu/TREE06
@@ -18,6 +18,5 @@ CONFIG_RCU_NOCB_CPU=n
CONFIG_DEBUG_LOCK_ALLOC=y
CONFIG_PROVE_LOCKING=y
#CHECK#CONFIG_PROVE_RCU=y
-CONFIG_RCU_CPU_STALL_INFO=n
CONFIG_DEBUG_OBJECTS_RCU_HEAD=y
CONFIG_RCU_EXPERT=y
diff --git a/tools/testing/selftests/rcutorture/configs/rcu/TREE07 b/tools/testing/selftests/rcutorture/configs/rcu/TREE07
index f422af4ff5a3..3956b4131f72 100644
--- a/tools/testing/selftests/rcutorture/configs/rcu/TREE07
+++ b/tools/testing/selftests/rcutorture/configs/rcu/TREE07
@@ -17,6 +17,5 @@ CONFIG_RCU_FANOUT=2
CONFIG_RCU_FANOUT_LEAF=2
CONFIG_RCU_NOCB_CPU=n
CONFIG_DEBUG_LOCK_ALLOC=n
-CONFIG_RCU_CPU_STALL_INFO=n
CONFIG_DEBUG_OBJECTS_RCU_HEAD=n
CONFIG_RCU_EXPERT=y
diff --git a/tools/testing/selftests/rcutorture/configs/rcu/TREE08 b/tools/testing/selftests/rcutorture/configs/rcu/TREE08
index a24d2ca30646..bb9b0c1a23c2 100644
--- a/tools/testing/selftests/rcutorture/configs/rcu/TREE08
+++ b/tools/testing/selftests/rcutorture/configs/rcu/TREE08
@@ -19,7 +19,6 @@ CONFIG_RCU_NOCB_CPU_ALL=y
CONFIG_DEBUG_LOCK_ALLOC=n
CONFIG_PROVE_LOCKING=y
#CHECK#CONFIG_PROVE_RCU=y
-CONFIG_RCU_CPU_STALL_INFO=n
CONFIG_RCU_BOOST=n
CONFIG_DEBUG_OBJECTS_RCU_HEAD=n
CONFIG_RCU_EXPERT=y
diff --git a/tools/testing/selftests/rcutorture/configs/rcu/TREE08-T b/tools/testing/selftests/rcutorture/configs/rcu/TREE08-T
index b2b8cea69dc9..2ad13f0d29cc 100644
--- a/tools/testing/selftests/rcutorture/configs/rcu/TREE08-T
+++ b/tools/testing/selftests/rcutorture/configs/rcu/TREE08-T
@@ -17,6 +17,5 @@ CONFIG_RCU_FANOUT_LEAF=2
CONFIG_RCU_NOCB_CPU=y
CONFIG_RCU_NOCB_CPU_ALL=y
CONFIG_DEBUG_LOCK_ALLOC=n
-CONFIG_RCU_CPU_STALL_INFO=n
CONFIG_RCU_BOOST=n
CONFIG_DEBUG_OBJECTS_RCU_HEAD=n
diff --git a/tools/testing/selftests/rcutorture/configs/rcu/TREE09 b/tools/testing/selftests/rcutorture/configs/rcu/TREE09
index aa4ed08d999d..6710e749d9de 100644
--- a/tools/testing/selftests/rcutorture/configs/rcu/TREE09
+++ b/tools/testing/selftests/rcutorture/configs/rcu/TREE09
@@ -13,7 +13,6 @@ CONFIG_SUSPEND=n
CONFIG_HIBERNATION=n
CONFIG_RCU_NOCB_CPU=n
CONFIG_DEBUG_LOCK_ALLOC=n
-CONFIG_RCU_CPU_STALL_INFO=n
CONFIG_RCU_BOOST=n
CONFIG_DEBUG_OBJECTS_RCU_HEAD=n
#CHECK#CONFIG_RCU_EXPERT=n
diff --git a/tools/testing/selftests/rcutorture/doc/TREE_RCU-kconfig.txt b/tools/testing/selftests/rcutorture/doc/TREE_RCU-kconfig.txt
index b24c0004fc49..657f3a035488 100644
--- a/tools/testing/selftests/rcutorture/doc/TREE_RCU-kconfig.txt
+++ b/tools/testing/selftests/rcutorture/doc/TREE_RCU-kconfig.txt
@@ -16,7 +16,6 @@ CONFIG_PROVE_LOCKING -- Do several, covering CONFIG_DEBUG_LOCK_ALLOC=y and not.
CONFIG_PROVE_RCU -- Hardwired to CONFIG_PROVE_LOCKING.
CONFIG_RCU_BOOST -- one of PREEMPT_RCU.
CONFIG_RCU_KTHREAD_PRIO -- set to 2 for _BOOST testing.
-CONFIG_RCU_CPU_STALL_INFO -- Now default, avoid at least twice.
CONFIG_RCU_FANOUT -- Cover hierarchy, but overlap with others.
CONFIG_RCU_FANOUT_LEAF -- Do one non-default.
CONFIG_RCU_FAST_NO_HZ -- Do one, but not with CONFIG_RCU_NOCB_CPU_ALL.
--
1.8.1.5
--
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