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authorFrederic Weisbecker <fweisbec@gmail.com>2009-12-05 09:44:31 +0100
committerFrederic Weisbecker <fweisbec@gmail.com>2009-12-06 08:27:18 +0100
commitb326e9560a28fc3e950637ef51847ed8f05c1335 (patch)
tree0804c8c4f28d4ae152d5e9205ce5a958f0d26b79 /kernel
parent2f0993e0fb663c49e4d1e02654f6203246be4817 (diff)
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hw-breakpoints: Use overflow handler instead of the event callback
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>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/hw_breakpoint.c17
-rw-r--r--kernel/perf_event.c24
-rw-r--r--kernel/trace/trace_ksym.c5
3 files changed, 17 insertions, 29 deletions
diff --git a/kernel/hw_breakpoint.c b/kernel/hw_breakpoint.c
index 2d10b01..b600fc2 100644
--- a/kernel/hw_breakpoint.c
+++ b/kernel/hw_breakpoint.c
@@ -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;
diff --git a/kernel/perf_event.c b/kernel/perf_event.c
index 6b7ddba..fd43ff4 100644
--- a/kernel/perf_event.c
+++ b/kernel/perf_event.c
@@ -4286,15 +4286,8 @@ static void bp_perf_event_destroy(struct perf_event *event)
static const struct pmu *bp_perf_event_init(struct perf_event *bp)
{
int err;
- /*
- * The breakpoint is already filled if we haven't created the counter
- * through perf syscall
- * FIXME: manage to get trigerred to NULL if it comes from syscalls
- */
- if (!bp->callback)
- err = register_perf_hw_breakpoint(bp);
- else
- err = __register_perf_hw_breakpoint(bp);
+
+ err = register_perf_hw_breakpoint(bp);
if (err)
return ERR_PTR(err);
@@ -4390,7 +4383,7 @@ perf_event_alloc(struct perf_event_attr *attr,
struct perf_event_context *ctx,
struct perf_event *group_leader,
struct perf_event *parent_event,
- perf_callback_t callback,
+ perf_overflow_handler_t overflow_handler,
gfp_t gfpflags)
{
const struct pmu *pmu;
@@ -4433,10 +4426,10 @@ perf_event_alloc(struct perf_event_attr *attr,
event->state = PERF_EVENT_STATE_INACTIVE;
- if (!callback && parent_event)
- callback = parent_event->callback;
+ if (!overflow_handler && parent_event)
+ overflow_handler = parent_event->overflow_handler;
- event->callback = callback;
+ event->overflow_handler = overflow_handler;
if (attr->disabled)
event->state = PERF_EVENT_STATE_OFF;
@@ -4776,7 +4769,8 @@ err_put_context:
*/
struct perf_event *
perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
- pid_t pid, perf_callback_t callback)
+ pid_t pid,
+ perf_overflow_handler_t overflow_handler)
{
struct perf_event *event;
struct perf_event_context *ctx;
@@ -4793,7 +4787,7 @@ perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
}
event = perf_event_alloc(attr, cpu, ctx, NULL,
- NULL, callback, GFP_KERNEL);
+ NULL, overflow_handler, GFP_KERNEL);
if (IS_ERR(event)) {
err = PTR_ERR(event);
goto err_put_context;
diff --git a/kernel/trace/trace_ksym.c b/kernel/trace/trace_ksym.c
index ddfa0fd..acb87d4 100644
--- a/kernel/trace/trace_ksym.c
+++ b/kernel/trace/trace_ksym.c
@@ -79,11 +79,12 @@ void ksym_collect_stats(unsigned long hbp_hit_addr)
}
#endif /* CONFIG_PROFILE_KSYM_TRACER */
-void ksym_hbp_handler(struct perf_event *hbp, void *data)
+void ksym_hbp_handler(struct perf_event *hbp, int nmi,
+ struct perf_sample_data *data,
+ struct pt_regs *regs)
{
struct ring_buffer_event *event;
struct ksym_trace_entry *entry;
- struct pt_regs *regs = data;
struct ring_buffer *buffer;
int pc;