[tip:perfcounters/urgent] perf_counter: Push inherit into perf_counter_alloc()

tip-bot for Peter Zijlstra
2009-06-23T10:04:48Z

Commit-ID: b84fbc9fb1d943e2c5f4efe52ed0e3c93a4bdb6a
Gitweb: http://git.kernel.org/tip/b84fbc9fb1d943e2c5f4efe52ed0e3c93a4bdb6a
Author: Peter Zijlstra <a.p.zijlstra@chello.nl>
AuthorDate: Mon, 22 Jun 2009 13:57:40 +0200
Committer: Ingo Molnar <mingo@elte.hu>
CommitDate: Tue, 23 Jun 2009 11:42:45 +0200

perf_counter: Push inherit into perf_counter_alloc()

Teach perf_counter_alloc() about inheritance so that we can
optimize the inherit path in the next patch.

Remove the child_counter->atrr.inherit = 1 line because the
only way to get there is if parent_counter->attr.inherit == 1
and we copy the attrs.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

---
kernel/perf_counter.c | 14 ++++++--------
1 files changed, 6 insertions(+), 8 deletions(-)

diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c
index 7515c76..0a45490 100644
--- a/kernel/perf_counter.c
+++ b/kernel/perf_counter.c
@@ -3568,6 +3568,7 @@ perf_counter_alloc(struct perf_counter_attr *attr,
int cpu,
struct perf_counter_context *ctx,
struct perf_counter *group_leader,
+ struct perf_counter *parent_counter,
gfp_t gfpflags)
{
const struct pmu *pmu;
@@ -3603,6 +3604,8 @@ perf_counter_alloc(struct perf_counter_attr *attr,
counter->ctx = ctx;
counter->oncpu = -1;

+ counter->parent = parent_counter;
+
counter->ns = get_pid_ns(current->nsproxy->pid_ns);
counter->id = atomic64_inc_return(&perf_counter_id);

@@ -3827,7 +3830,7 @@ SYSCALL_DEFINE5(perf_counter_open,
}

counter = perf_counter_alloc(&attr, cpu, ctx, group_leader,
- GFP_KERNEL);
+ NULL, GFP_KERNEL);
ret = PTR_ERR(counter);
if (IS_ERR(counter))
goto err_put_context;
@@ -3893,7 +3896,8 @@ inherit_counter(struct perf_counter *parent_counter,

child_counter = perf_counter_alloc(&parent_counter->attr,
parent_counter->cpu, child_ctx,
- group_leader, GFP_KERNEL);
+ group_leader, parent_counter,
+ GFP_KERNEL);
if (IS_ERR(child_counter))
return child_counter;
get_ctx(child_ctx);
@@ -3916,12 +3920,6 @@ inherit_counter(struct perf_counter *parent_counter,
*/
add_counter_to_ctx(child_counter, child_ctx);

- child_counter->parent = parent_counter;
- /*
- * inherit into child's child as well:
- */
- child_counter->attr.inherit = 1;
-
/*
* Get a reference to the parent filp - we will fput it
* when the child counter exits. This is safe to do because