[PATCH] cgroup, cleanup: Delete PF_EXITING checks from cgroup_exit() callbacks

[PATCH] cgroup, cleanup: Delete PF_EXITING checks from cgroup_exit() callbacks

[Kirill Tkhai]

Remove useless checks and outdates commentaries.

Signed-off-by: Kirill Tkhai <ktkhai@odin.com>
---
 kernel/events/core.c |    8 --------
 kernel/sched/core.c  |    8 --------
 2 files changed, 16 deletions(-)

diff --git a/kernel/events/core.c b/kernel/events/core.c
index ae16867..94bd500 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -9219,14 +9219,6 @@ static void perf_cgroup_exit(struct cgroup_subsys_state *css,
 			     struct cgroup_subsys_state *old_css,
 			     struct task_struct *task)
 {
-	/*
-	 * cgroup_exit() is called in the copy_process() failure path.
-	 * Ignore this case since the task hasn't ran yet, this avoids
-	 * trying to poke a half freed task state from generic code.
-	 */
-	if (!(task->flags & PF_EXITING))
-		return;
-
 	task_function_call(task, __perf_cgroup_move, task);
 }
 
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index b3386c6..f8509be 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -8167,14 +8167,6 @@ static void cpu_cgroup_exit(struct cgroup_subsys_state *css,
 			    struct cgroup_subsys_state *old_css,
 			    struct task_struct *task)
 {
-	/*
-	 * cgroup_exit() is called in the copy_process() failure path.
-	 * Ignore this case since the task hasn't ran yet, this avoids
-	 * trying to poke a half freed task state from generic code.
-	 */
-	if (!(task->flags & PF_EXITING))
-		return;
-
 	sched_move_task(task);
 }
 

Re: [PATCH] cgroup, cleanup: Delete PF_EXITING checks from cgroup_exit() callbacks

[Peter Zijlstra]

On Mon, Aug 31, 2015 at 02:49:59PM +0300, Kirill Tkhai wrote:
> Remove useless checks and outdates commentaries.

A slightly bigger Changelog could do, maybe also referring to the commit
that made these checks obsolete.

Re: [PATCH] cgroup, cleanup: Delete PF_EXITING checks from cgroup_exit() callbacks

[Kirill Tkhai]

On 31.08.2015 14:53, Peter Zijlstra wrote:
> On Mon, Aug 31, 2015 at 02:49:59PM +0300, Kirill Tkhai wrote:
>> Remove useless checks and outdates commentaries.
> 
> A slightly bigger Changelog could do, maybe also referring to the commit
> that made these checks obsolete.
> 

[PATCH] cgroup, cleanup: Delete PF_EXITING checks from cgroup_exit() callbacks

cgroup_exit() is not called from copy_process() after commit e8604cb43690b781:

	"cgroup: fix spurious lockdep warning in cgroup_exit()", it's only called

from do_exit(). So these checks are useless and commentaries are obsolete. Remove them.

Signed-off-by: Kirill Tkhai <ktkhai@odin.com>
---
 kernel/events/core.c |    8 --------
 kernel/sched/core.c  |    8 --------
 2 files changed, 16 deletions(-)

diff --git a/kernel/events/core.c b/kernel/events/core.c
index ae16867..94bd500 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -9219,14 +9219,6 @@ static void perf_cgroup_exit(struct cgroup_subsys_state *css,
 			     struct cgroup_subsys_state *old_css,
 			     struct task_struct *task)
 {
-	/*
-	 * cgroup_exit() is called in the copy_process() failure path.
-	 * Ignore this case since the task hasn't ran yet, this avoids
-	 * trying to poke a half freed task state from generic code.
-	 */
-	if (!(task->flags & PF_EXITING))
-		return;
-
 	task_function_call(task, __perf_cgroup_move, task);
 }
 
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index b3386c6..f8509be 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -8167,14 +8167,6 @@ static void cpu_cgroup_exit(struct cgroup_subsys_state *css,
 			    struct cgroup_subsys_state *old_css,
 			    struct task_struct *task)
 {
-	/*
-	 * cgroup_exit() is called in the copy_process() failure path.
-	 * Ignore this case since the task hasn't ran yet, this avoids
-	 * trying to poke a half freed task state from generic code.
-	 */
-	if (!(task->flags & PF_EXITING))
-		return;
-
 	sched_move_task(task);
 }
 

Re: [PATCH] cgroup, cleanup: Delete PF_EXITING checks from cgroup_exit() callbacks

[Peter Zijlstra]

I made that two patches, like:

---
Subject: perf: Delete PF_EXITING checks from perf_cgroup_exit() callback
From: Kirill Tkhai <ktkhai@odin.com>
Date: Mon, 31 Aug 2015 15:12:56 +0300

cgroup_exit() is not called from copy_process() after commit:

  e8604cb43690 ("cgroup: fix spurious lockdep warning in cgroup_exit()")

from do_exit(). So this check is useless and the comment is obsolete.

Signed-off-by: Kirill Tkhai <ktkhai@odin.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: http://lkml.kernel.org/r/55E444C8.3020402@odin.com
---
 kernel/events/core.c |    8 --------
 1 file changed, 8 deletions(-)

--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -9219,14 +9219,6 @@ static void perf_cgroup_exit(struct cgro
 			     struct cgroup_subsys_state *old_css,
 			     struct task_struct *task)
 {
-	/*
-	 * cgroup_exit() is called in the copy_process() failure path.
-	 * Ignore this case since the task hasn't ran yet, this avoids
-	 * trying to poke a half freed task state from generic code.
-	 */
-	if (!(task->flags & PF_EXITING))
-		return;
-
 	task_function_call(task, __perf_cgroup_move, task);
 }
 

[tip:sched/core] sched/core: Delete PF_EXITING checks from cpu_cgroup_exit() callback

[tip-bot for Kirill Tkhai]

Commit-ID:  446685e9bfa11174332fbb0b3218b37015fbf4ff
Gitweb:     http://git.kernel.org/tip/446685e9bfa11174332fbb0b3218b37015fbf4ff
Author:     Kirill Tkhai <ktkhai@odin.com>
AuthorDate: Mon, 31 Aug 2015 15:12:56 +0300
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Sun, 13 Sep 2015 09:52:51 +0200

sched/core: Delete PF_EXITING checks from cpu_cgroup_exit() callback

cgroup_exit() is not called from copy_process() after commit:

  e8604cb43690 ("cgroup: fix spurious lockdep warning in cgroup_exit()")

from do_exit(). So this check is useless and the comment is obsolete.

Signed-off-by: Kirill Tkhai <ktkhai@odin.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/55E444C8.3020402@odin.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 kernel/sched/core.c | 8 --------
 1 file changed, 8 deletions(-)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 7c099e6..37ab6f9 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -8193,14 +8193,6 @@ static void cpu_cgroup_exit(struct cgroup_subsys_state *css,
 			    struct cgroup_subsys_state *old_css,
 			    struct task_struct *task)
 {
-	/*
-	 * cgroup_exit() is called in the copy_process() failure path.
-	 * Ignore this case since the task hasn't ran yet, this avoids
-	 * trying to poke a half freed task state from generic code.
-	 */
-	if (!(task->flags & PF_EXITING))
-		return;
-
 	sched_move_task(task);
 }
 

[tip:perf/core] perf/core: Delete PF_EXITING checks from perf_cgroup_exit() callback

[tip-bot for Kirill Tkhai]

Commit-ID:  516792e67c39d31701641ab355acdb9cbfec0643
Gitweb:     http://git.kernel.org/tip/516792e67c39d31701641ab355acdb9cbfec0643
Author:     Kirill Tkhai <ktkhai@odin.com>
AuthorDate: Mon, 31 Aug 2015 15:12:56 +0300
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Sun, 13 Sep 2015 11:27:23 +0200

perf/core: Delete PF_EXITING checks from perf_cgroup_exit() callback

cgroup_exit() is not called from copy_process() after commit:

  e8604cb43690 ("cgroup: fix spurious lockdep warning in cgroup_exit()")

from do_exit(). So this check is useless and the comment is obsolete.

Signed-off-by: Kirill Tkhai <ktkhai@odin.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Link: http://lkml.kernel.org/r/55E444C8.3020402@odin.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 kernel/events/core.c | 8 --------
 1 file changed, 8 deletions(-)

diff --git a/kernel/events/core.c b/kernel/events/core.c
index f548f69..76e64be 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -9297,14 +9297,6 @@ static void perf_cgroup_exit(struct cgroup_subsys_state *css,
 			     struct cgroup_subsys_state *old_css,
 			     struct task_struct *task)
 {
-	/*
-	 * cgroup_exit() is called in the copy_process() failure path.
-	 * Ignore this case since the task hasn't ran yet, this avoids
-	 * trying to poke a half freed task state from generic code.
-	 */
-	if (!(task->flags & PF_EXITING))
-		return;
-
 	task_function_call(task, __perf_cgroup_move, task);
 }