[tip:perfcounters/core] perf_counter: Stop open coding unclone_ctx

tip-bot for Peter Zijlstra
2009-07-10T10:41:53Z

Commit-ID: 71a851b4d2a815adcfac09c1adda7ef6811fde66
Gitweb: http://git.kernel.org/tip/71a851b4d2a815adcfac09c1adda7ef6811fde66
Author: Peter Zijlstra <a.p.zijlstra@chello.nl>
AuthorDate: Fri, 10 Jul 2009 09:06:56 +0200
Committer: Ingo Molnar <mingo@elte.hu>
CommitDate: Fri, 10 Jul 2009 10:28:40 +0200

perf_counter: Stop open coding unclone_ctx

Instead of open coding the unclone context thingy, put it in
a common function.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

---
kernel/perf_counter.c | 36 +++++++++++++++++-------------------
1 files changed, 17 insertions(+), 19 deletions(-)

diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c
index d55a50d..8bf997d 100644
--- a/kernel/perf_counter.c
+++ b/kernel/perf_counter.c
@@ -146,6 +146,14 @@ static void put_ctx(struct perf_counter_context *ctx)
}
}

+static void unclone_ctx(struct perf_counter_context *ctx)
+{
+ if (ctx->parent_ctx) {
+ put_ctx(ctx->parent_ctx);
+ ctx->parent_ctx = NULL;
+ }
+}
+
/*
* Get the perf_counter_context for a task and lock it.
* This has to cope with with the fact that until it is locked,
@@ -1463,10 +1471,8 @@ static void perf_counter_enable_on_exec(struct task_struct *task)
/*
* Unclone this context if we enabled any counter.
*/
- if (enabled && ctx->parent_ctx) {
- put_ctx(ctx->parent_ctx);
- ctx->parent_ctx = NULL;
- }
+ if (enabled)
+ unclone_ctx(ctx);

spin_unlock(&ctx->lock);

@@ -1526,7 +1532,6 @@ __perf_counter_init_context(struct perf_counter_context *ctx,

static struct perf_counter_context *find_get_context(pid_t pid, int cpu)
{
- struct perf_counter_context *parent_ctx;
struct perf_counter_context *ctx;
struct perf_cpu_context *cpuctx;
struct task_struct *task;
@@ -1586,11 +1591,7 @@ static struct perf_counter_context *find_get_context(pid_t pid, int cpu)
retry:
ctx = perf_lock_task_context(task, &flags);
if (ctx) {
- parent_ctx = ctx->parent_ctx;
- if (parent_ctx) {
- put_ctx(parent_ctx);
- ctx->parent_ctx = NULL; /* no longer a clone */
- }
+ unclone_ctx(ctx);
spin_unlock_irqrestore(&ctx->lock, flags);
}

@@ -4255,15 +4256,12 @@ void perf_counter_exit_task(struct task_struct *child)
*/
spin_lock(&child_ctx->lock);
child->perf_counter_ctxp = NULL;
- if (child_ctx->parent_ctx) {
- /*
- * This context is a clone; unclone it so it can't get
- * swapped to another process while we're removing all
- * the counters from it.
- */
- put_ctx(child_ctx->parent_ctx);
- child_ctx->parent_ctx = NULL;
- }
+ /*
+ * If this context is a clone; unclone it so it can't get
+ * swapped to another process while we're removing all
+ * the counters from it.
+ */
+ unclone_ctx(child_ctx);
spin_unlock(&child_ctx->lock);
local_irq_restore(flags);