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perf: Add context field to perf_event

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The perf_event overflow handler does not receive any caller-derived
argument, so many callers need to resort to looking up the perf_event
in their local data structure.  This is ugly and doesn't scale if a
single callback services many perf_events.

Fix by adding a context parameter to perf_event_create_kernel_counter()
(and derived hardware breakpoints APIs) and storing it in the perf_event.
The field can be accessed from the callback as event->overflow_handler_context.
All callers are updated.

Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1309362157-6596-2-git-send-email-avi@redhat.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Avi Kivity 2011-06-29 18:42:35 +03:00 • committed by Ingo Molnar
parent 89d6c0b5bd
commit 4dc0da8696
12 changed files with 44 additions and 20 deletions
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10
kernel/events/hw_breakpoint.c
View file

@ -431,9 +431,11 @@ int register_perf_hw_breakpoint(struct perf_event *bp)
struct perf_event *
register_user_hw_breakpoint(struct perf_event_attr *attr,
perf_overflow_handler_t triggered,
void *context,
struct task_struct *tsk)
{
return perf_event_create_kernel_counter(attr, -1, tsk, triggered);
return perf_event_create_kernel_counter(attr, -1, tsk, triggered,
context);
}
EXPORT_SYMBOL_GPL(register_user_hw_breakpoint);
@ -502,7 +504,8 @@ EXPORT_SYMBOL_GPL(unregister_hw_breakpoint);
*/
struct perf_event * __percpu *
register_wide_hw_breakpoint(struct perf_event_attr *attr,
perf_overflow_handler_t triggered)
perf_overflow_handler_t triggered,
void *context)
{
struct perf_event * __percpu *cpu_events, **pevent, *bp;
long err;
@ -515,7 +518,8 @@ register_wide_hw_breakpoint(struct perf_event_attr *attr,
get_online_cpus();
for_each_online_cpu(cpu) {
pevent = per_cpu_ptr(cpu_events, cpu);
bp = perf_event_create_kernel_counter(attr, cpu, NULL, triggered);
bp = perf_event_create_kernel_counter(attr, cpu, NULL,
triggered, context);
*pevent = bp;