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hw-breakpoints: Use overflow handler instead of the event callback

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struct perf_event::event callback was called when a breakpoint
triggers. But this is a rather opaque callback, pretty
tied-only to the breakpoint API and not really integrated into perf
as it triggers even when we don't overflow.

We prefer to use overflow_handler() as it fits into the perf events
rules, being called only when we overflow.

Reported-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: "K. Prasad" <prasad@linux.vnet.ibm.com>
This commit is contained in:
Frederic Weisbecker
2009-12-05 09:44:31 +01:00
parent 2f0993e0fb
commit b326e9560a
8 changed files with 48 additions and 57 deletions
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17
kernel/hw_breakpoint.c
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@@ -259,7 +259,7 @@ void release_bp_slot(struct perf_event *bp)
}
int __register_perf_hw_breakpoint(struct perf_event *bp)
int register_perf_hw_breakpoint(struct perf_event *bp)
{
int ret;
@@ -276,19 +276,12 @@ int __register_perf_hw_breakpoint(struct perf_event *bp)
* This is a quick hack that will be removed soon, once we remove
* the tmp breakpoints from ptrace
*/
if (!bp->attr.disabled || bp->callback == perf_bp_event)
if (!bp->attr.disabled || !bp->overflow_handler)
ret = arch_validate_hwbkpt_settings(bp, bp->ctx->task);
return ret;
}
int register_perf_hw_breakpoint(struct perf_event *bp)
{
bp->callback = perf_bp_event;
return __register_perf_hw_breakpoint(bp);
}
/**
* register_user_hw_breakpoint - register a hardware breakpoint for user space
* @attr: breakpoint attributes
@@ -297,7 +290,7 @@ int register_perf_hw_breakpoint(struct perf_event *bp)
*/
struct perf_event *
register_user_hw_breakpoint(struct perf_event_attr *attr,
perf_callback_t triggered,
perf_overflow_handler_t triggered,
struct task_struct *tsk)
{
return perf_event_create_kernel_counter(attr, -1, tsk->pid, triggered);
@@ -322,7 +315,7 @@ modify_user_hw_breakpoint(struct perf_event *bp, struct perf_event_attr *attr)
unregister_hw_breakpoint(bp);
return perf_event_create_kernel_counter(attr, -1, bp->ctx->task->pid,
bp->callback);
bp->overflow_handler);
}
EXPORT_SYMBOL_GPL(modify_user_hw_breakpoint);
@@ -347,7 +340,7 @@ EXPORT_SYMBOL_GPL(unregister_hw_breakpoint);
*/
struct perf_event **
register_wide_hw_breakpoint(struct perf_event_attr *attr,
perf_callback_t triggered)
perf_overflow_handler_t triggered)
{
struct perf_event **cpu_events, **pevent, *bp;
long err;