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| author | Wang Nan <wangnan0@huawei.com> | 2016-03-28 06:41:30 +0000 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2016-03-31 10:30:47 +0200 |
| commit | 1879445dfa7bbd6fe21b09c5cc72f4934798afed (patch) | |
| tree | dfd9ff5fae69b6e9a7d3abb0f813fbee6f083e92 /arch/arm64/kernel | |
| parent | 86e7972f690c1017fd086cdfe53d8524e68c661c (diff) | |
| download | linux-1879445dfa7bbd6fe21b09c5cc72f4934798afed.tar.gz linux-1879445dfa7bbd6fe21b09c5cc72f4934798afed.tar.bz2 linux-1879445dfa7bbd6fe21b09c5cc72f4934798afed.zip | |
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/20130708121557.GA17211@twins.programming.kicks-ass.net
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 <wangnan0@huawei.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: <pi3orama@163.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: Zefan Li <lizefan@huawei.com>
Link: http://lkml.kernel.org/r/1459147292-239310-3-git-send-email-wangnan0@huawei.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/arm64/kernel')
| -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: |