The following commit has been merged into the locking/core branch of tip:
Commit-ID: 2f0df49c89acaa58571d509830bc481250699885
Gitweb: https://git.kernel.org/tip/2f0df49c89acaa58571d509830bc481250699885
Author: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
AuthorDate: Fri, 11 Dec 2020 16:37:54 -05:00
Committer: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
CommitterDate: Fri, 22 Jan 2021 11:08:56 +01:00
jump_label: Do not profile branch annotations
While running my branch profiler that checks for incorrect "likely" and
"unlikely"s around the kernel, there's a large number of them that are
incorrect due to being "static_branches".
As static_branches are rather special, as they are likely or unlikely for
other reasons than normal annotations are used for, there's no reason to
have them be profiled.
Expose the "unlikely_notrace" and "likely_notrace" so that the
static_branch can use them, and have them be ignored by the branch
profilers.
Signed-off-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Link: https://lkml.kernel.org/r/20201211163754.585174b9@xxxxxxxxxxxxxxxxxx
---
include/linux/compiler.h | 2 ++
include/linux/jump_label.h | 12 ++++++------
2 files changed, 8 insertions(+), 6 deletions(-)
diff --git a/include/linux/compiler.h b/include/linux/compiler.h
index b8fe0c2..df5b405 100644
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -76,6 +76,8 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val,
#else
# define likely(x) __builtin_expect(!!(x), 1)
# define unlikely(x) __builtin_expect(!!(x), 0)
+# define likely_notrace(x) likely(x)
+# define unlikely_notrace(x) unlikely(x)
#endif
/* Optimization barrier */
diff --git a/include/linux/jump_label.h b/include/linux/jump_label.h
index 3280962..d926912 100644
--- a/include/linux/jump_label.h
+++ b/include/linux/jump_label.h
@@ -261,14 +261,14 @@ static __always_inline void jump_label_init(void)
static __always_inline bool static_key_false(struct static_key *key)
{
- if (unlikely(static_key_count(key) > 0))
+ if (unlikely_notrace(static_key_count(key) > 0))
return true;
return false;
}
static __always_inline bool static_key_true(struct static_key *key)
{
- if (likely(static_key_count(key) > 0))
+ if (likely_notrace(static_key_count(key) > 0))
return true;
return false;
}
@@ -460,7 +460,7 @@ extern bool ____wrong_branch_error(void);
branch = !arch_static_branch_jump(&(x)->key, true); \
else \
branch = ____wrong_branch_error(); \
- likely(branch); \
+ likely_notrace(branch); \
})
#define static_branch_unlikely(x) \
@@ -472,13 +472,13 @@ extern bool ____wrong_branch_error(void);
branch = arch_static_branch(&(x)->key, false); \
else \
branch = ____wrong_branch_error(); \
- unlikely(branch); \
+ unlikely_notrace(branch); \
})
#else /* !CONFIG_JUMP_LABEL */
-#define static_branch_likely(x) likely(static_key_enabled(&(x)->key))
-#define static_branch_unlikely(x) unlikely(static_key_enabled(&(x)->key))
+#define static_branch_likely(x) likely_notrace(static_key_enabled(&(x)->key))
+#define static_branch_unlikely(x) unlikely_notrace(static_key_enabled(&(x)->key))
#endif /* CONFIG_JUMP_LABEL */
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