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Message-ID: <20090620165300.GA26119@elte.hu>
Date: Sat, 20 Jun 2009 18:53:00 +0200
From: Ingo Molnar <mingo@...e.hu>
To: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: linux-kernel@...r.kernel.org, Steven Rostedt <rostedt@...dmis.org>,
Andrew Morton <akpm@...ux-foundation.org>,
Thomas Gleixner <tglx@...utronix.de>
Subject: [GIT PULL] tracing fixes
Linus,
Please pull the latest tracing-fixes-for-linus git tree from:
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip.git tracing-fixes-for-linus
Thanks,
Ingo
------------------>
Frederic Weisbecker (2):
tracing/urgent: fix unbalanced ftrace_start_up
tracing/urgent: warn in case of ftrace_start_up inbalance
Li Zefan (6):
tracing: fix a typo in tracing_cpumask_write()
tracing: replace a GFP_ATOMIC with GFP_KERNEL allocation
tracing/filters: operand can be negative
tracing/filters: strloc should be unsigned short
tracing/filters: free filter_string in destroy_preds()
tracing/filters: fix race between filter setting and module unload
Rusty Russell (1):
cpumask: use new operators in kernel/trace
Steven Rostedt (14):
ring-buffer: prevent adding write in discarded area
ring-buffer: have benchmark test handle discarded events
ring-buffer: remove unused variable
ring-buffer: use commit counters for commit pointer accounting
tracing: update sample event documentation
ring-buffer: use BUF_PAGE_HDR_SIZE in calculating index
ring-buffer: remove useless warn on check
ring-buffer: remove useless compile check for buffer_page size
ring-buffer: check for less than two in size allocation
ring-buffer: add locks around rb_per_cpu_empty
ring-buffer: do not grab locks in nmi
ring-buffer: have benchmark test print to trace buffer
function-graph: disable when both x86_32 and optimize for size are configured
function-graph: add stack frame test
Wu Zhangjin (1):
tracing: fix undeclared 'PAGE_SIZE' in include/linux/trace_seq.h
arch/powerpc/kernel/ftrace.c | 2 +-
arch/s390/kernel/ftrace.c | 2 +-
arch/x86/Kconfig | 1 +
arch/x86/kernel/entry_32.S | 2 +
arch/x86/kernel/entry_64.S | 2 +
arch/x86/kernel/ftrace.c | 6 +-
include/linux/ftrace.h | 4 +-
include/linux/trace_seq.h | 2 +
kernel/trace/Kconfig | 8 +
kernel/trace/ftrace.c | 7 +
kernel/trace/kmemtrace.c | 2 +-
kernel/trace/ring_buffer.c | 309 +++++++++++++++++-----------
kernel/trace/ring_buffer_benchmark.c | 45 +++--
kernel/trace/trace.c | 8 +-
kernel/trace/trace_events_filter.c | 37 ++--
kernel/trace/trace_functions.c | 8 +-
kernel/trace/trace_functions_graph.c | 36 +++-
samples/trace_events/Makefile | 8 +
samples/trace_events/trace-events-sample.h | 27 ++-
19 files changed, 331 insertions(+), 185 deletions(-)
diff --git a/arch/powerpc/kernel/ftrace.c b/arch/powerpc/kernel/ftrace.c
index 2d182f1..58d6a61 100644
--- a/arch/powerpc/kernel/ftrace.c
+++ b/arch/powerpc/kernel/ftrace.c
@@ -605,7 +605,7 @@ void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr)
return;
}
- if (ftrace_push_return_trace(old, self_addr, &trace.depth) == -EBUSY) {
+ if (ftrace_push_return_trace(old, self_addr, &trace.depth, 0) == -EBUSY) {
*parent = old;
return;
}
diff --git a/arch/s390/kernel/ftrace.c b/arch/s390/kernel/ftrace.c
index 82ddfd3..3e298e6 100644
--- a/arch/s390/kernel/ftrace.c
+++ b/arch/s390/kernel/ftrace.c
@@ -190,7 +190,7 @@ unsigned long prepare_ftrace_return(unsigned long ip, unsigned long parent)
goto out;
if (unlikely(atomic_read(¤t->tracing_graph_pause)))
goto out;
- if (ftrace_push_return_trace(parent, ip, &trace.depth) == -EBUSY)
+ if (ftrace_push_return_trace(parent, ip, &trace.depth, 0) == -EBUSY)
goto out;
trace.func = ftrace_mcount_call_adjust(ip) & PSW_ADDR_INSN;
/* Only trace if the calling function expects to. */
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 356d2ec..fcf12af 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -33,6 +33,7 @@ config X86
select HAVE_DYNAMIC_FTRACE
select HAVE_FUNCTION_TRACER
select HAVE_FUNCTION_GRAPH_TRACER
+ select HAVE_FUNCTION_GRAPH_FP_TEST
select HAVE_FUNCTION_TRACE_MCOUNT_TEST
select HAVE_FTRACE_NMI_ENTER if DYNAMIC_FTRACE
select HAVE_FTRACE_SYSCALLS
diff --git a/arch/x86/kernel/entry_32.S b/arch/x86/kernel/entry_32.S
index c929add..0d4b285 100644
--- a/arch/x86/kernel/entry_32.S
+++ b/arch/x86/kernel/entry_32.S
@@ -1154,6 +1154,7 @@ ENTRY(ftrace_graph_caller)
pushl %edx
movl 0xc(%esp), %edx
lea 0x4(%ebp), %eax
+ movl (%ebp), %ecx
subl $MCOUNT_INSN_SIZE, %edx
call prepare_ftrace_return
popl %edx
@@ -1168,6 +1169,7 @@ return_to_handler:
pushl %eax
pushl %ecx
pushl %edx
+ movl %ebp, %eax
call ftrace_return_to_handler
movl %eax, 0xc(%esp)
popl %edx
diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index de74f0a..c251be7 100644
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -135,6 +135,7 @@ ENTRY(ftrace_graph_caller)
leaq 8(%rbp), %rdi
movq 0x38(%rsp), %rsi
+ movq (%rbp), %rdx
subq $MCOUNT_INSN_SIZE, %rsi
call prepare_ftrace_return
@@ -150,6 +151,7 @@ GLOBAL(return_to_handler)
/* Save the return values */
movq %rax, (%rsp)
movq %rdx, 8(%rsp)
+ movq %rbp, %rdi
call ftrace_return_to_handler
diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index b79c553..d94e1ea 100644
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -408,7 +408,8 @@ int ftrace_disable_ftrace_graph_caller(void)
* Hook the return address and push it in the stack of return addrs
* in current thread info.
*/
-void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr)
+void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr,
+ unsigned long frame_pointer)
{
unsigned long old;
int faulted;
@@ -453,7 +454,8 @@ void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr)
return;
}
- if (ftrace_push_return_trace(old, self_addr, &trace.depth) == -EBUSY) {
+ if (ftrace_push_return_trace(old, self_addr, &trace.depth,
+ frame_pointer) == -EBUSY) {
*parent = old;
return;
}
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 39b95c5..dc3b132 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -362,6 +362,7 @@ struct ftrace_ret_stack {
unsigned long func;
unsigned long long calltime;
unsigned long long subtime;
+ unsigned long fp;
};
/*
@@ -372,7 +373,8 @@ struct ftrace_ret_stack {
extern void return_to_handler(void);
extern int
-ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth);
+ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth,
+ unsigned long frame_pointer);
/*
* Sometimes we don't want to trace a function with the function
diff --git a/include/linux/trace_seq.h b/include/linux/trace_seq.h
index c68bccb..c134dd1 100644
--- a/include/linux/trace_seq.h
+++ b/include/linux/trace_seq.h
@@ -3,6 +3,8 @@
#include <linux/fs.h>
+#include <asm/page.h>
+
/*
* Trace sequences are used to allow a function to call several other functions
* to create a string of data to use (up to a max of PAGE_SIZE.
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index 4a13e5a..b17ed87 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -18,6 +18,13 @@ config HAVE_FUNCTION_TRACER
config HAVE_FUNCTION_GRAPH_TRACER
bool
+config HAVE_FUNCTION_GRAPH_FP_TEST
+ bool
+ help
+ An arch may pass in a unique value (frame pointer) to both the
+ entering and exiting of a function. On exit, the value is compared
+ and if it does not match, then it will panic the kernel.
+
config HAVE_FUNCTION_TRACE_MCOUNT_TEST
bool
help
@@ -121,6 +128,7 @@ config FUNCTION_GRAPH_TRACER
bool "Kernel Function Graph Tracer"
depends on HAVE_FUNCTION_GRAPH_TRACER
depends on FUNCTION_TRACER
+ depends on !X86_32 || !CC_OPTIMIZE_FOR_SIZE
default y
help
Enable the kernel to trace a function at both its return
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index bb60732..3718d55 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -1224,6 +1224,13 @@ static void ftrace_shutdown(int command)
return;
ftrace_start_up--;
+ /*
+ * Just warn in case of unbalance, no need to kill ftrace, it's not
+ * critical but the ftrace_call callers may be never nopped again after
+ * further ftrace uses.
+ */
+ WARN_ON_ONCE(ftrace_start_up < 0);
+
if (!ftrace_start_up)
command |= FTRACE_DISABLE_CALLS;
diff --git a/kernel/trace/kmemtrace.c b/kernel/trace/kmemtrace.c
index 86cdf67..1edaa95 100644
--- a/kernel/trace/kmemtrace.c
+++ b/kernel/trace/kmemtrace.c
@@ -186,7 +186,7 @@ static int kmem_trace_init(struct trace_array *tr)
int cpu;
kmemtrace_array = tr;
- for_each_cpu_mask(cpu, cpu_possible_map)
+ for_each_cpu(cpu, cpu_possible_mask)
tracing_reset(tr, cpu);
kmemtrace_start_probes();
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 2e642b2..589b3ee 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -205,6 +205,7 @@ EXPORT_SYMBOL_GPL(tracing_is_on);
#define RB_EVNT_HDR_SIZE (offsetof(struct ring_buffer_event, array))
#define RB_ALIGNMENT 4U
#define RB_MAX_SMALL_DATA (RB_ALIGNMENT * RINGBUF_TYPE_DATA_TYPE_LEN_MAX)
+#define RB_EVNT_MIN_SIZE 8U /* two 32bit words */
/* define RINGBUF_TYPE_DATA for 'case RINGBUF_TYPE_DATA:' */
#define RINGBUF_TYPE_DATA 0 ... RINGBUF_TYPE_DATA_TYPE_LEN_MAX
@@ -414,6 +415,8 @@ struct ring_buffer_per_cpu {
unsigned long overrun;
unsigned long read;
local_t entries;
+ local_t committing;
+ local_t commits;
u64 write_stamp;
u64 read_stamp;
atomic_t record_disabled;
@@ -617,12 +620,6 @@ static void rb_free_cpu_buffer(struct ring_buffer_per_cpu *cpu_buffer)
kfree(cpu_buffer);
}
-/*
- * Causes compile errors if the struct buffer_page gets bigger
- * than the struct page.
- */
-extern int ring_buffer_page_too_big(void);
-
#ifdef CONFIG_HOTPLUG_CPU
static int rb_cpu_notify(struct notifier_block *self,
unsigned long action, void *hcpu);
@@ -645,11 +642,6 @@ struct ring_buffer *__ring_buffer_alloc(unsigned long size, unsigned flags,
int bsize;
int cpu;
- /* Paranoid! Optimizes out when all is well */
- if (sizeof(struct buffer_page) > sizeof(struct page))
- ring_buffer_page_too_big();
-
-
/* keep it in its own cache line */
buffer = kzalloc(ALIGN(sizeof(*buffer), cache_line_size()),
GFP_KERNEL);
@@ -665,8 +657,8 @@ struct ring_buffer *__ring_buffer_alloc(unsigned long size, unsigned flags,
buffer->reader_lock_key = key;
/* need at least two pages */
- if (buffer->pages == 1)
- buffer->pages++;
+ if (buffer->pages < 2)
+ buffer->pages = 2;
/*
* In case of non-hotplug cpu, if the ring-buffer is allocated
@@ -1010,12 +1002,12 @@ rb_event_index(struct ring_buffer_event *event)
{
unsigned long addr = (unsigned long)event;
- return (addr & ~PAGE_MASK) - (PAGE_SIZE - BUF_PAGE_SIZE);
+ return (addr & ~PAGE_MASK) - BUF_PAGE_HDR_SIZE;
}
static inline int
-rb_is_commit(struct ring_buffer_per_cpu *cpu_buffer,
- struct ring_buffer_event *event)
+rb_event_is_commit(struct ring_buffer_per_cpu *cpu_buffer,
+ struct ring_buffer_event *event)
{
unsigned long addr = (unsigned long)event;
unsigned long index;
@@ -1028,31 +1020,6 @@ rb_is_commit(struct ring_buffer_per_cpu *cpu_buffer,
}
static void
-rb_set_commit_event(struct ring_buffer_per_cpu *cpu_buffer,
- struct ring_buffer_event *event)
-{
- unsigned long addr = (unsigned long)event;
- unsigned long index;
-
- index = rb_event_index(event);
- addr &= PAGE_MASK;
-
- while (cpu_buffer->commit_page->page != (void *)addr) {
- if (RB_WARN_ON(cpu_buffer,
- cpu_buffer->commit_page == cpu_buffer->tail_page))
- return;
- cpu_buffer->commit_page->page->commit =
- cpu_buffer->commit_page->write;
- rb_inc_page(cpu_buffer, &cpu_buffer->commit_page);
- cpu_buffer->write_stamp =
- cpu_buffer->commit_page->page->time_stamp;
- }
-
- /* Now set the commit to the event's index */
- local_set(&cpu_buffer->commit_page->page->commit, index);
-}
-
-static void
rb_set_commit_to_write(struct ring_buffer_per_cpu *cpu_buffer)
{
/*
@@ -1170,6 +1137,59 @@ static unsigned rb_calculate_event_length(unsigned length)
return length;
}
+static inline void
+rb_reset_tail(struct ring_buffer_per_cpu *cpu_buffer,
+ struct buffer_page *tail_page,
+ unsigned long tail, unsigned long length)
+{
+ struct ring_buffer_event *event;
+
+ /*
+ * Only the event that crossed the page boundary
+ * must fill the old tail_page with padding.
+ */
+ if (tail >= BUF_PAGE_SIZE) {
+ local_sub(length, &tail_page->write);
+ return;
+ }
+
+ event = __rb_page_index(tail_page, tail);
+
+ /*
+ * If this event is bigger than the minimum size, then
+ * we need to be careful that we don't subtract the
+ * write counter enough to allow another writer to slip
+ * in on this page.
+ * We put in a discarded commit instead, to make sure
+ * that this space is not used again.
+ *
+ * If we are less than the minimum size, we don't need to
+ * worry about it.
+ */
+ if (tail > (BUF_PAGE_SIZE - RB_EVNT_MIN_SIZE)) {
+ /* No room for any events */
+
+ /* Mark the rest of the page with padding */
+ rb_event_set_padding(event);
+
+ /* Set the write back to the previous setting */
+ local_sub(length, &tail_page->write);
+ return;
+ }
+
+ /* Put in a discarded event */
+ event->array[0] = (BUF_PAGE_SIZE - tail) - RB_EVNT_HDR_SIZE;
+ event->type_len = RINGBUF_TYPE_PADDING;
+ /* time delta must be non zero */
+ event->time_delta = 1;
+ /* Account for this as an entry */
+ local_inc(&tail_page->entries);
+ local_inc(&cpu_buffer->entries);
+
+ /* Set write to end of buffer */
+ length = (tail + length) - BUF_PAGE_SIZE;
+ local_sub(length, &tail_page->write);
+}
static struct ring_buffer_event *
rb_move_tail(struct ring_buffer_per_cpu *cpu_buffer,
@@ -1179,7 +1199,6 @@ rb_move_tail(struct ring_buffer_per_cpu *cpu_buffer,
{
struct buffer_page *next_page, *head_page, *reader_page;
struct ring_buffer *buffer = cpu_buffer->buffer;
- struct ring_buffer_event *event;
bool lock_taken = false;
unsigned long flags;
@@ -1264,26 +1283,7 @@ rb_move_tail(struct ring_buffer_per_cpu *cpu_buffer,
cpu_buffer->tail_page->page->time_stamp = *ts;
}
- /*
- * The actual tail page has moved forward.
- */
- if (tail < BUF_PAGE_SIZE) {
- /* Mark the rest of the page with padding */
- event = __rb_page_index(tail_page, tail);
- rb_event_set_padding(event);
- }
-
- /* Set the write back to the previous setting */
- local_sub(length, &tail_page->write);
-
- /*
- * If this was a commit entry that failed,
- * increment that too
- */
- if (tail_page == cpu_buffer->commit_page &&
- tail == rb_commit_index(cpu_buffer)) {
- rb_set_commit_to_write(cpu_buffer);
- }
+ rb_reset_tail(cpu_buffer, tail_page, tail, length);
__raw_spin_unlock(&cpu_buffer->lock);
local_irq_restore(flags);
@@ -1293,7 +1293,7 @@ rb_move_tail(struct ring_buffer_per_cpu *cpu_buffer,
out_reset:
/* reset write */
- local_sub(length, &tail_page->write);
+ rb_reset_tail(cpu_buffer, tail_page, tail, length);
if (likely(lock_taken))
__raw_spin_unlock(&cpu_buffer->lock);
@@ -1323,9 +1323,6 @@ __rb_reserve_next(struct ring_buffer_per_cpu *cpu_buffer,
/* We reserved something on the buffer */
- if (RB_WARN_ON(cpu_buffer, write > BUF_PAGE_SIZE))
- return NULL;
-
event = __rb_page_index(tail_page, tail);
rb_update_event(event, type, length);
@@ -1334,11 +1331,11 @@ __rb_reserve_next(struct ring_buffer_per_cpu *cpu_buffer,
local_inc(&tail_page->entries);
/*
- * If this is a commit and the tail is zero, then update
- * this page's time stamp.
+ * If this is the first commit on the page, then update
+ * its timestamp.
*/
- if (!tail && rb_is_commit(cpu_buffer, event))
- cpu_buffer->commit_page->page->time_stamp = *ts;
+ if (!tail)
+ tail_page->page->time_stamp = *ts;
return event;
}
@@ -1407,16 +1404,16 @@ rb_add_time_stamp(struct ring_buffer_per_cpu *cpu_buffer,
return -EAGAIN;
/* Only a commited time event can update the write stamp */
- if (rb_is_commit(cpu_buffer, event)) {
+ if (rb_event_is_commit(cpu_buffer, event)) {
/*
- * If this is the first on the page, then we need to
- * update the page itself, and just put in a zero.
+ * If this is the first on the page, then it was
+ * updated with the page itself. Try to discard it
+ * and if we can't just make it zero.
*/
if (rb_event_index(event)) {
event->time_delta = *delta & TS_MASK;
event->array[0] = *delta >> TS_SHIFT;
} else {
- cpu_buffer->commit_page->page->time_stamp = *ts;
/* try to discard, since we do not need this */
if (!rb_try_to_discard(cpu_buffer, event)) {
/* nope, just zero it */
@@ -1442,6 +1439,44 @@ rb_add_time_stamp(struct ring_buffer_per_cpu *cpu_buffer,
return ret;
}
+static void rb_start_commit(struct ring_buffer_per_cpu *cpu_buffer)
+{
+ local_inc(&cpu_buffer->committing);
+ local_inc(&cpu_buffer->commits);
+}
+
+static void rb_end_commit(struct ring_buffer_per_cpu *cpu_buffer)
+{
+ unsigned long commits;
+
+ if (RB_WARN_ON(cpu_buffer,
+ !local_read(&cpu_buffer->committing)))
+ return;
+
+ again:
+ commits = local_read(&cpu_buffer->commits);
+ /* synchronize with interrupts */
+ barrier();
+ if (local_read(&cpu_buffer->committing) == 1)
+ rb_set_commit_to_write(cpu_buffer);
+
+ local_dec(&cpu_buffer->committing);
+
+ /* synchronize with interrupts */
+ barrier();
+
+ /*
+ * Need to account for interrupts coming in between the
+ * updating of the commit page and the clearing of the
+ * committing counter.
+ */
+ if (unlikely(local_read(&cpu_buffer->commits) != commits) &&
+ !local_read(&cpu_buffer->committing)) {
+ local_inc(&cpu_buffer->committing);
+ goto again;
+ }
+}
+
static struct ring_buffer_event *
rb_reserve_next_event(struct ring_buffer_per_cpu *cpu_buffer,
unsigned long length)
@@ -1451,6 +1486,8 @@ rb_reserve_next_event(struct ring_buffer_per_cpu *cpu_buffer,
int commit = 0;
int nr_loops = 0;
+ rb_start_commit(cpu_buffer);
+
length = rb_calculate_event_length(length);
again:
/*
@@ -1463,7 +1500,7 @@ rb_reserve_next_event(struct ring_buffer_per_cpu *cpu_buffer,
* Bail!
*/
if (RB_WARN_ON(cpu_buffer, ++nr_loops > 1000))
- return NULL;
+ goto out_fail;
ts = rb_time_stamp(cpu_buffer->buffer, cpu_buffer->cpu);
@@ -1494,7 +1531,7 @@ rb_reserve_next_event(struct ring_buffer_per_cpu *cpu_buffer,
commit = rb_add_time_stamp(cpu_buffer, &ts, &delta);
if (commit == -EBUSY)
- return NULL;
+ goto out_fail;
if (commit == -EAGAIN)
goto again;
@@ -1508,28 +1545,19 @@ rb_reserve_next_event(struct ring_buffer_per_cpu *cpu_buffer,
if (unlikely(PTR_ERR(event) == -EAGAIN))
goto again;
- if (!event) {
- if (unlikely(commit))
- /*
- * Ouch! We needed a timestamp and it was commited. But
- * we didn't get our event reserved.
- */
- rb_set_commit_to_write(cpu_buffer);
- return NULL;
- }
+ if (!event)
+ goto out_fail;
- /*
- * If the timestamp was commited, make the commit our entry
- * now so that we will update it when needed.
- */
- if (unlikely(commit))
- rb_set_commit_event(cpu_buffer, event);
- else if (!rb_is_commit(cpu_buffer, event))
+ if (!rb_event_is_commit(cpu_buffer, event))
delta = 0;
event->time_delta = delta;
return event;
+
+ out_fail:
+ rb_end_commit(cpu_buffer);
+ return NULL;
}
#define TRACE_RECURSIVE_DEPTH 16
@@ -1639,13 +1667,14 @@ static void rb_commit(struct ring_buffer_per_cpu *cpu_buffer,
{
local_inc(&cpu_buffer->entries);
- /* Only process further if we own the commit */
- if (!rb_is_commit(cpu_buffer, event))
- return;
-
- cpu_buffer->write_stamp += event->time_delta;
+ /*
+ * The event first in the commit queue updates the
+ * time stamp.
+ */
+ if (rb_event_is_commit(cpu_buffer, event))
+ cpu_buffer->write_stamp += event->time_delta;
- rb_set_commit_to_write(cpu_buffer);
+ rb_end_commit(cpu_buffer);
}
/**
@@ -1734,15 +1763,15 @@ void ring_buffer_discard_commit(struct ring_buffer *buffer,
/* The event is discarded regardless */
rb_event_discard(event);
+ cpu = smp_processor_id();
+ cpu_buffer = buffer->buffers[cpu];
+
/*
* This must only be called if the event has not been
* committed yet. Thus we can assume that preemption
* is still disabled.
*/
- RB_WARN_ON(buffer, preemptible());
-
- cpu = smp_processor_id();
- cpu_buffer = buffer->buffers[cpu];
+ RB_WARN_ON(buffer, !local_read(&cpu_buffer->committing));
if (!rb_try_to_discard(cpu_buffer, event))
goto out;
@@ -1753,13 +1782,7 @@ void ring_buffer_discard_commit(struct ring_buffer *buffer,
*/
local_inc(&cpu_buffer->entries);
out:
- /*
- * If a write came in and pushed the tail page
- * we still need to update the commit pointer
- * if we were the commit.
- */
- if (rb_is_commit(cpu_buffer, event))
- rb_set_commit_to_write(cpu_buffer);
+ rb_end_commit(cpu_buffer);
trace_recursive_unlock();
@@ -2443,6 +2466,21 @@ rb_iter_peek(struct ring_buffer_iter *iter, u64 *ts)
}
EXPORT_SYMBOL_GPL(ring_buffer_iter_peek);
+static inline int rb_ok_to_lock(void)
+{
+ /*
+ * If an NMI die dumps out the content of the ring buffer
+ * do not grab locks. We also permanently disable the ring
+ * buffer too. A one time deal is all you get from reading
+ * the ring buffer from an NMI.
+ */
+ if (likely(!in_nmi() && !oops_in_progress))
+ return 1;
+
+ tracing_off_permanent();
+ return 0;
+}
+
/**
* ring_buffer_peek - peek at the next event to be read
* @buffer: The ring buffer to read
@@ -2458,14 +2496,20 @@ ring_buffer_peek(struct ring_buffer *buffer, int cpu, u64 *ts)
struct ring_buffer_per_cpu *cpu_buffer = buffer->buffers[cpu];
struct ring_buffer_event *event;
unsigned long flags;
+ int dolock;
if (!cpumask_test_cpu(cpu, buffer->cpumask))
return NULL;
+ dolock = rb_ok_to_lock();
again:
- spin_lock_irqsave(&cpu_buffer->reader_lock, flags);
+ local_irq_save(flags);
+ if (dolock)
+ spin_lock(&cpu_buffer->reader_lock);
event = rb_buffer_peek(buffer, cpu, ts);
- spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
+ if (dolock)
+ spin_unlock(&cpu_buffer->reader_lock);
+ local_irq_restore(flags);
if (event && event->type_len == RINGBUF_TYPE_PADDING) {
cpu_relax();
@@ -2517,6 +2561,9 @@ ring_buffer_consume(struct ring_buffer *buffer, int cpu, u64 *ts)
struct ring_buffer_per_cpu *cpu_buffer;
struct ring_buffer_event *event = NULL;
unsigned long flags;
+ int dolock;
+
+ dolock = rb_ok_to_lock();
again:
/* might be called in atomic */
@@ -2526,7 +2573,9 @@ ring_buffer_consume(struct ring_buffer *buffer, int cpu, u64 *ts)
goto out;
cpu_buffer = buffer->buffers[cpu];
- spin_lock_irqsave(&cpu_buffer->reader_lock, flags);
+ local_irq_save(flags);
+ if (dolock)
+ spin_lock(&cpu_buffer->reader_lock);
event = rb_buffer_peek(buffer, cpu, ts);
if (!event)
@@ -2535,7 +2584,9 @@ ring_buffer_consume(struct ring_buffer *buffer, int cpu, u64 *ts)
rb_advance_reader(cpu_buffer);
out_unlock:
- spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
+ if (dolock)
+ spin_unlock(&cpu_buffer->reader_lock);
+ local_irq_restore(flags);
out:
preempt_enable();
@@ -2677,6 +2728,8 @@ rb_reset_cpu(struct ring_buffer_per_cpu *cpu_buffer)
cpu_buffer->overrun = 0;
cpu_buffer->read = 0;
local_set(&cpu_buffer->entries, 0);
+ local_set(&cpu_buffer->committing, 0);
+ local_set(&cpu_buffer->commits, 0);
cpu_buffer->write_stamp = 0;
cpu_buffer->read_stamp = 0;
@@ -2731,12 +2784,25 @@ EXPORT_SYMBOL_GPL(ring_buffer_reset);
int ring_buffer_empty(struct ring_buffer *buffer)
{
struct ring_buffer_per_cpu *cpu_buffer;
+ unsigned long flags;
+ int dolock;
int cpu;
+ int ret;
+
+ dolock = rb_ok_to_lock();
/* yes this is racy, but if you don't like the race, lock the buffer */
for_each_buffer_cpu(buffer, cpu) {
cpu_buffer = buffer->buffers[cpu];
- if (!rb_per_cpu_empty(cpu_buffer))
+ local_irq_save(flags);
+ if (dolock)
+ spin_lock(&cpu_buffer->reader_lock);
+ ret = rb_per_cpu_empty(cpu_buffer);
+ if (dolock)
+ spin_unlock(&cpu_buffer->reader_lock);
+ local_irq_restore(flags);
+
+ if (!ret)
return 0;
}
@@ -2752,14 +2818,23 @@ EXPORT_SYMBOL_GPL(ring_buffer_empty);
int ring_buffer_empty_cpu(struct ring_buffer *buffer, int cpu)
{
struct ring_buffer_per_cpu *cpu_buffer;
+ unsigned long flags;
+ int dolock;
int ret;
if (!cpumask_test_cpu(cpu, buffer->cpumask))
return 1;
+ dolock = rb_ok_to_lock();
+
cpu_buffer = buffer->buffers[cpu];
+ local_irq_save(flags);
+ if (dolock)
+ spin_lock(&cpu_buffer->reader_lock);
ret = rb_per_cpu_empty(cpu_buffer);
-
+ if (dolock)
+ spin_unlock(&cpu_buffer->reader_lock);
+ local_irq_restore(flags);
return ret;
}
@@ -3105,7 +3180,7 @@ static int rb_cpu_notify(struct notifier_block *self,
switch (action) {
case CPU_UP_PREPARE:
case CPU_UP_PREPARE_FROZEN:
- if (cpu_isset(cpu, *buffer->cpumask))
+ if (cpumask_test_cpu(cpu, buffer->cpumask))
return NOTIFY_OK;
buffer->buffers[cpu] =
@@ -3116,7 +3191,7 @@ static int rb_cpu_notify(struct notifier_block *self,
return NOTIFY_OK;
}
smp_wmb();
- cpu_set(cpu, *buffer->cpumask);
+ cpumask_set_cpu(cpu, buffer->cpumask);
break;
case CPU_DOWN_PREPARE:
case CPU_DOWN_PREPARE_FROZEN:
diff --git a/kernel/trace/ring_buffer_benchmark.c b/kernel/trace/ring_buffer_benchmark.c
index 8d68e14..573d3cc 100644
--- a/kernel/trace/ring_buffer_benchmark.c
+++ b/kernel/trace/ring_buffer_benchmark.c
@@ -102,8 +102,10 @@ static enum event_status read_page(int cpu)
event = (void *)&rpage->data[i];
switch (event->type_len) {
case RINGBUF_TYPE_PADDING:
- /* We don't expect any padding */
- KILL_TEST();
+ /* failed writes may be discarded events */
+ if (!event->time_delta)
+ KILL_TEST();
+ inc = event->array[0] + 4;
break;
case RINGBUF_TYPE_TIME_EXTEND:
inc = 8;
@@ -119,7 +121,7 @@ static enum event_status read_page(int cpu)
KILL_TEST();
break;
}
- inc = event->array[0];
+ inc = event->array[0] + 4;
break;
default:
entry = ring_buffer_event_data(event);
@@ -201,7 +203,7 @@ static void ring_buffer_producer(void)
* Hammer the buffer for 10 secs (this may
* make the system stall)
*/
- pr_info("Starting ring buffer hammer\n");
+ trace_printk("Starting ring buffer hammer\n");
do_gettimeofday(&start_tv);
do {
struct ring_buffer_event *event;
@@ -237,7 +239,7 @@ static void ring_buffer_producer(void)
#endif
} while (end_tv.tv_sec < (start_tv.tv_sec + RUN_TIME) && !kill_test);
- pr_info("End ring buffer hammer\n");
+ trace_printk("End ring buffer hammer\n");
if (consumer) {
/* Init both completions here to avoid races */
@@ -260,49 +262,50 @@ static void ring_buffer_producer(void)
overruns = ring_buffer_overruns(buffer);
if (kill_test)
- pr_info("ERROR!\n");
- pr_info("Time: %lld (usecs)\n", time);
- pr_info("Overruns: %lld\n", overruns);
+ trace_printk("ERROR!\n");
+ trace_printk("Time: %lld (usecs)\n", time);
+ trace_printk("Overruns: %lld\n", overruns);
if (disable_reader)
- pr_info("Read: (reader disabled)\n");
+ trace_printk("Read: (reader disabled)\n");
else
- pr_info("Read: %ld (by %s)\n", read,
+ trace_printk("Read: %ld (by %s)\n", read,
read_events ? "events" : "pages");
- pr_info("Entries: %lld\n", entries);
- pr_info("Total: %lld\n", entries + overruns + read);
- pr_info("Missed: %ld\n", missed);
- pr_info("Hit: %ld\n", hit);
+ trace_printk("Entries: %lld\n", entries);
+ trace_printk("Total: %lld\n", entries + overruns + read);
+ trace_printk("Missed: %ld\n", missed);
+ trace_printk("Hit: %ld\n", hit);
/* Convert time from usecs to millisecs */
do_div(time, USEC_PER_MSEC);
if (time)
hit /= (long)time;
else
- pr_info("TIME IS ZERO??\n");
+ trace_printk("TIME IS ZERO??\n");
- pr_info("Entries per millisec: %ld\n", hit);
+ trace_printk("Entries per millisec: %ld\n", hit);
if (hit) {
/* Calculate the average time in nanosecs */
avg = NSEC_PER_MSEC / hit;
- pr_info("%ld ns per entry\n", avg);
+ trace_printk("%ld ns per entry\n", avg);
}
if (missed) {
if (time)
missed /= (long)time;
- pr_info("Total iterations per millisec: %ld\n", hit + missed);
+ trace_printk("Total iterations per millisec: %ld\n",
+ hit + missed);
/* it is possible that hit + missed will overflow and be zero */
if (!(hit + missed)) {
- pr_info("hit + missed overflowed and totalled zero!\n");
+ trace_printk("hit + missed overflowed and totalled zero!\n");
hit--; /* make it non zero */
}
/* Caculate the average time in nanosecs */
avg = NSEC_PER_MSEC / (hit + missed);
- pr_info("%ld ns per entry\n", avg);
+ trace_printk("%ld ns per entry\n", avg);
}
}
@@ -353,7 +356,7 @@ static int ring_buffer_producer_thread(void *arg)
ring_buffer_producer();
- pr_info("Sleeping for 10 secs\n");
+ trace_printk("Sleeping for 10 secs\n");
set_current_state(TASK_INTERRUPTIBLE);
schedule_timeout(HZ * SLEEP_TIME);
__set_current_state(TASK_RUNNING);
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 8acd9b8..0f57f1b 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -2191,11 +2191,12 @@ tracing_cpumask_write(struct file *filp, const char __user *ubuf,
if (!alloc_cpumask_var(&tracing_cpumask_new, GFP_KERNEL))
return -ENOMEM;
- mutex_lock(&tracing_cpumask_update_lock);
err = cpumask_parse_user(ubuf, count, tracing_cpumask_new);
if (err)
goto err_unlock;
+ mutex_lock(&tracing_cpumask_update_lock);
+
local_irq_disable();
__raw_spin_lock(&ftrace_max_lock);
for_each_tracing_cpu(cpu) {
@@ -2223,8 +2224,7 @@ tracing_cpumask_write(struct file *filp, const char __user *ubuf,
return count;
err_unlock:
- mutex_unlock(&tracing_cpumask_update_lock);
- free_cpumask_var(tracing_cpumask);
+ free_cpumask_var(tracing_cpumask_new);
return err;
}
@@ -3627,7 +3627,7 @@ tracing_stats_read(struct file *filp, char __user *ubuf,
struct trace_seq *s;
unsigned long cnt;
- s = kmalloc(sizeof(*s), GFP_ATOMIC);
+ s = kmalloc(sizeof(*s), GFP_KERNEL);
if (!s)
return ENOMEM;
diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c
index db6e54b..936c621 100644
--- a/kernel/trace/trace_events_filter.c
+++ b/kernel/trace/trace_events_filter.c
@@ -27,8 +27,6 @@
#include "trace.h"
#include "trace_output.h"
-static DEFINE_MUTEX(filter_mutex);
-
enum filter_op_ids
{
OP_OR,
@@ -178,7 +176,7 @@ static int filter_pred_string(struct filter_pred *pred, void *event,
static int filter_pred_strloc(struct filter_pred *pred, void *event,
int val1, int val2)
{
- int str_loc = *(int *)(event + pred->offset);
+ unsigned short str_loc = *(unsigned short *)(event + pred->offset);
char *addr = (char *)(event + str_loc);
int cmp, match;
@@ -294,12 +292,12 @@ void print_event_filter(struct ftrace_event_call *call, struct trace_seq *s)
{
struct event_filter *filter = call->filter;
- mutex_lock(&filter_mutex);
+ mutex_lock(&event_mutex);
if (filter->filter_string)
trace_seq_printf(s, "%s\n", filter->filter_string);
else
trace_seq_printf(s, "none\n");
- mutex_unlock(&filter_mutex);
+ mutex_unlock(&event_mutex);
}
void print_subsystem_event_filter(struct event_subsystem *system,
@@ -307,12 +305,12 @@ void print_subsystem_event_filter(struct event_subsystem *system,
{
struct event_filter *filter = system->filter;
- mutex_lock(&filter_mutex);
+ mutex_lock(&event_mutex);
if (filter->filter_string)
trace_seq_printf(s, "%s\n", filter->filter_string);
else
trace_seq_printf(s, "none\n");
- mutex_unlock(&filter_mutex);
+ mutex_unlock(&event_mutex);
}
static struct ftrace_event_field *
@@ -381,6 +379,7 @@ void destroy_preds(struct ftrace_event_call *call)
filter_free_pred(filter->preds[i]);
}
kfree(filter->preds);
+ kfree(filter->filter_string);
kfree(filter);
call->filter = NULL;
}
@@ -433,7 +432,6 @@ static void filter_free_subsystem_preds(struct event_subsystem *system)
filter->n_preds = 0;
}
- mutex_lock(&event_mutex);
list_for_each_entry(call, &ftrace_events, list) {
if (!call->define_fields)
continue;
@@ -443,7 +441,6 @@ static void filter_free_subsystem_preds(struct event_subsystem *system)
remove_filter_string(call->filter);
}
}
- mutex_unlock(&event_mutex);
}
static int filter_add_pred_fn(struct filter_parse_state *ps,
@@ -546,6 +543,7 @@ static int filter_add_pred(struct filter_parse_state *ps,
filter_pred_fn_t fn;
unsigned long long val;
int string_type;
+ int ret;
pred->fn = filter_pred_none;
@@ -581,7 +579,11 @@ static int filter_add_pred(struct filter_parse_state *ps,
pred->not = 1;
return filter_add_pred_fn(ps, call, pred, fn);
} else {
- if (strict_strtoull(pred->str_val, 0, &val)) {
+ if (field->is_signed)
+ ret = strict_strtoll(pred->str_val, 0, &val);
+ else
+ ret = strict_strtoull(pred->str_val, 0, &val);
+ if (ret) {
parse_error(ps, FILT_ERR_ILLEGAL_INTVAL, 0);
return -EINVAL;
}
@@ -625,7 +627,6 @@ static int filter_add_subsystem_pred(struct filter_parse_state *ps,
filter->preds[filter->n_preds] = pred;
filter->n_preds++;
- mutex_lock(&event_mutex);
list_for_each_entry(call, &ftrace_events, list) {
if (!call->define_fields)
@@ -636,14 +637,12 @@ static int filter_add_subsystem_pred(struct filter_parse_state *ps,
err = filter_add_pred(ps, call, pred);
if (err) {
- mutex_unlock(&event_mutex);
filter_free_subsystem_preds(system);
parse_error(ps, FILT_ERR_BAD_SUBSYS_FILTER, 0);
goto out;
}
replace_filter_string(call->filter, filter_string);
}
- mutex_unlock(&event_mutex);
out:
return err;
}
@@ -1070,12 +1069,12 @@ int apply_event_filter(struct ftrace_event_call *call, char *filter_string)
struct filter_parse_state *ps;
- mutex_lock(&filter_mutex);
+ mutex_lock(&event_mutex);
if (!strcmp(strstrip(filter_string), "0")) {
filter_disable_preds(call);
remove_filter_string(call->filter);
- mutex_unlock(&filter_mutex);
+ mutex_unlock(&event_mutex);
return 0;
}
@@ -1103,7 +1102,7 @@ out:
postfix_clear(ps);
kfree(ps);
out_unlock:
- mutex_unlock(&filter_mutex);
+ mutex_unlock(&event_mutex);
return err;
}
@@ -1115,12 +1114,12 @@ int apply_subsystem_event_filter(struct event_subsystem *system,
struct filter_parse_state *ps;
- mutex_lock(&filter_mutex);
+ mutex_lock(&event_mutex);
if (!strcmp(strstrip(filter_string), "0")) {
filter_free_subsystem_preds(system);
remove_filter_string(system->filter);
- mutex_unlock(&filter_mutex);
+ mutex_unlock(&event_mutex);
return 0;
}
@@ -1148,7 +1147,7 @@ out:
postfix_clear(ps);
kfree(ps);
out_unlock:
- mutex_unlock(&filter_mutex);
+ mutex_unlock(&event_mutex);
return err;
}
diff --git a/kernel/trace/trace_functions.c b/kernel/trace/trace_functions.c
index c9a0b7d..90f1347 100644
--- a/kernel/trace/trace_functions.c
+++ b/kernel/trace/trace_functions.c
@@ -193,9 +193,11 @@ static void tracing_start_function_trace(void)
static void tracing_stop_function_trace(void)
{
ftrace_function_enabled = 0;
- /* OK if they are not registered */
- unregister_ftrace_function(&trace_stack_ops);
- unregister_ftrace_function(&trace_ops);
+
+ if (func_flags.val & TRACE_FUNC_OPT_STACK)
+ unregister_ftrace_function(&trace_stack_ops);
+ else
+ unregister_ftrace_function(&trace_ops);
}
static int func_set_flag(u32 old_flags, u32 bit, int set)
diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c
index 8b59241..d2249ab 100644
--- a/kernel/trace/trace_functions_graph.c
+++ b/kernel/trace/trace_functions_graph.c
@@ -57,7 +57,8 @@ static struct tracer_flags tracer_flags = {
/* Add a function return address to the trace stack on thread info.*/
int
-ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth)
+ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth,
+ unsigned long frame_pointer)
{
unsigned long long calltime;
int index;
@@ -85,6 +86,7 @@ ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth)
current->ret_stack[index].func = func;
current->ret_stack[index].calltime = calltime;
current->ret_stack[index].subtime = 0;
+ current->ret_stack[index].fp = frame_pointer;
*depth = index;
return 0;
@@ -92,7 +94,8 @@ ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth)
/* Retrieve a function return address to the trace stack on thread info.*/
static void
-ftrace_pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret)
+ftrace_pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret,
+ unsigned long frame_pointer)
{
int index;
@@ -106,6 +109,31 @@ ftrace_pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret)
return;
}
+#ifdef CONFIG_HAVE_FUNCTION_GRAPH_FP_TEST
+ /*
+ * The arch may choose to record the frame pointer used
+ * and check it here to make sure that it is what we expect it
+ * to be. If gcc does not set the place holder of the return
+ * address in the frame pointer, and does a copy instead, then
+ * the function graph trace will fail. This test detects this
+ * case.
+ *
+ * Currently, x86_32 with optimize for size (-Os) makes the latest
+ * gcc do the above.
+ */
+ if (unlikely(current->ret_stack[index].fp != frame_pointer)) {
+ ftrace_graph_stop();
+ WARN(1, "Bad frame pointer: expected %lx, received %lx\n"
+ " from func %pF return to %lx\n",
+ current->ret_stack[index].fp,
+ frame_pointer,
+ (void *)current->ret_stack[index].func,
+ current->ret_stack[index].ret);
+ *ret = (unsigned long)panic;
+ return;
+ }
+#endif
+
*ret = current->ret_stack[index].ret;
trace->func = current->ret_stack[index].func;
trace->calltime = current->ret_stack[index].calltime;
@@ -117,12 +145,12 @@ ftrace_pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret)
* Send the trace to the ring-buffer.
* @return the original return address.
*/
-unsigned long ftrace_return_to_handler(void)
+unsigned long ftrace_return_to_handler(unsigned long frame_pointer)
{
struct ftrace_graph_ret trace;
unsigned long ret;
- ftrace_pop_return_trace(&trace, &ret);
+ ftrace_pop_return_trace(&trace, &ret, frame_pointer);
trace.rettime = trace_clock_local();
ftrace_graph_return(&trace);
barrier();
diff --git a/samples/trace_events/Makefile b/samples/trace_events/Makefile
index 0d428dc..0f8d921 100644
--- a/samples/trace_events/Makefile
+++ b/samples/trace_events/Makefile
@@ -1,6 +1,14 @@
# builds the trace events example kernel modules;
# then to use one (as root): insmod <module_name.ko>
+# If you include a trace header outside of include/trace/events
+# then the file that does the #define CREATE_TRACE_POINTS must
+# have that tracer file in its main search path. This is because
+# define_trace.h will include it, and must be able to find it from
+# the include/trace directory.
+#
+# Here trace-events-sample.c does the CREATE_TRACE_POINTS.
+#
CFLAGS_trace-events-sample.o := -I$(src)
obj-$(CONFIG_SAMPLE_TRACE_EVENTS) += trace-events-sample.o
diff --git a/samples/trace_events/trace-events-sample.h b/samples/trace_events/trace-events-sample.h
index 128a897..9977a75 100644
--- a/samples/trace_events/trace-events-sample.h
+++ b/samples/trace_events/trace-events-sample.h
@@ -19,16 +19,21 @@
* If TRACE_SYSTEM is defined, that will be the directory created
* in the ftrace directory under /debugfs/tracing/events/<system>
*
- * The define_trace.h belowe will also look for a file name of
+ * The define_trace.h below will also look for a file name of
* TRACE_SYSTEM.h where TRACE_SYSTEM is what is defined here.
+ * In this case, it would look for sample.h
*
- * If you want a different system than file name, you can override
- * the header name by defining TRACE_INCLUDE_FILE
+ * If the header name will be different than the system name
+ * (as in this case), then you can override the header name that
+ * define_trace.h will look up by defining TRACE_INCLUDE_FILE
*
- * If this file was called, goofy.h, then we would define:
+ * This file is called trace-events-sample.h but we want the system
+ * to be called "sample". Therefore we must define the name of this
+ * file:
*
- * #define TRACE_INCLUDE_FILE goofy
+ * #define TRACE_INCLUDE_FILE trace-events-sample
*
+ * As we do an the bottom of this file.
*/
#undef TRACE_SYSTEM
#define TRACE_SYSTEM sample
@@ -99,13 +104,13 @@ TRACE_EVENT(foo_bar,
*
* #define TRACE_INCLUDE_PATH ../../samples/trace_events
*
- * But I chose to simply make it use the current directory and then in
- * the Makefile I added:
+ * But the safest and easiest way to simply make it use the directory
+ * that the file is in is to add in the Makefile:
*
- * CFLAGS_trace-events-sample.o := -I$(PWD)/samples/trace_events/
+ * CFLAGS_trace-events-sample.o := -I$(src)
*
* This will make sure the current path is part of the include
- * structure for our file so that we can find it.
+ * structure for our file so that define_trace.h can find it.
*
* I could have made only the top level directory the include:
*
@@ -115,8 +120,8 @@ TRACE_EVENT(foo_bar,
*
* #define TRACE_INCLUDE_PATH samples/trace_events
*
- * But then if something defines "samples" or "trace_events" then we
- * could risk that being converted too, and give us an unexpected
+ * But then if something defines "samples" or "trace_events" as a macro
+ * then we could risk that being converted too, and give us an unexpected
* result.
*/
#undef TRACE_INCLUDE_PATH
--
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