diff options
| author | Wang Nan <[email protected]> | 2016-03-28 06:41:30 +0000 |
|---|---|---|
| committer | Ingo Molnar <[email protected]> | 2016-03-31 10:30:47 +0200 |
| commit | 1879445dfa7bbd6fe21b09c5cc72f4934798afed (patch) | |
| tree | dfd9ff5fae69b6e9a7d3abb0f813fbee6f083e92 /arch/arm64/kernel/hw_breakpoint.c | |
| parent | 86e7972f690c1017fd086cdfe53d8524e68c661c (diff) | |
perf/core: Set event's default ::overflow_handler()
Set a default event->overflow_handler in perf_event_alloc() so don't
need to check event->overflow_handler in __perf_event_overflow().
Following commits can give a different default overflow_handler.
Initial idea comes from Peter:
http://lkml.kernel.org/r/[email protected]
Since the default value of event->overflow_handler is not NULL, existing
'if (!overflow_handler)' checks need to be changed.
is_default_overflow_handler() is introduced for this.
No extra performance overhead is introduced into the hot path because in the
original code we still need to read this handler from memory. A conditional
branch is avoided so actually we remove some instructions.
Signed-off-by: Wang Nan <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Cc: <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Alexei Starovoitov <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Brendan Gregg <[email protected]>
Cc: He Kuang <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Masami Hiramatsu <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Stephane Eranian <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Vince Weaver <[email protected]>
Cc: Zefan Li <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
Diffstat (limited to 'arch/arm64/kernel/hw_breakpoint.c')
| -rw-r--r-- | arch/arm64/kernel/hw_breakpoint.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/arm64/kernel/hw_breakpoint.c b/arch/arm64/kernel/hw_breakpoint.c index b45c95d34b83..4ef5373f9a76 100644 --- a/arch/arm64/kernel/hw_breakpoint.c +++ b/arch/arm64/kernel/hw_breakpoint.c @@ -616,7 +616,7 @@ static int breakpoint_handler(unsigned long unused, unsigned int esr, perf_bp_event(bp, regs); /* Do we need to handle the stepping? */ - if (!bp->overflow_handler) + if (is_default_overflow_handler(bp)) step = 1; unlock: rcu_read_unlock(); @@ -712,7 +712,7 @@ static int watchpoint_handler(unsigned long addr, unsigned int esr, perf_bp_event(wp, regs); /* Do we need to handle the stepping? */ - if (!wp->overflow_handler) + if (is_default_overflow_handler(wp)) step = 1; unlock: |