[RFC][PATCH 2/9] perf: Clean up ctx reference counting

From: Peter Zijlstra
Date: Sat Apr 09 2011 - 15:23:16 EST


Small cleanup to how we refcount in find_get_context(), this also
allows us to use put_ctx() to free things instead of using kfree().

Signed-off-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
---
kernel/perf_event.c | 10 +++-------
1 file changed, 3 insertions(+), 7 deletions(-)

Index: linux-2.6/kernel/perf_event.c
===================================================================
--- linux-2.6.orig/kernel/perf_event.c
+++ linux-2.6/kernel/perf_event.c
@@ -2831,16 +2831,12 @@ find_get_context(struct pmu *pmu, struct
unclone_ctx(ctx);
++ctx->pin_count;
raw_spin_unlock_irqrestore(&ctx->lock, flags);
- }
-
- if (!ctx) {
+ } else {
ctx = alloc_perf_context(pmu, task);
err = -ENOMEM;
if (!ctx)
goto errout;

- get_ctx(ctx);
-
err = 0;
mutex_lock(&task->perf_event_mutex);
/*
@@ -2852,14 +2848,14 @@ find_get_context(struct pmu *pmu, struct
else if (task->perf_event_ctxp[ctxn])
err = -EAGAIN;
else {
+ get_ctx(ctx);
++ctx->pin_count;
rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
}
mutex_unlock(&task->perf_event_mutex);

if (unlikely(err)) {
- put_task_struct(task);
- kfree(ctx);
+ put_ctx(ctx);

if (err == -EAGAIN)
goto retry;


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