* [PATCH] sched: fix rt_nr_migratory corruption raised in push_rt_task()
@ 2011-05-30 13:39 Hillf Danton
2011-05-31 7:36 ` Mike Galbraith
0 siblings, 1 reply; 8+ messages in thread
From: Hillf Danton @ 2011-05-30 13:39 UTC (permalink / raw)
To: LKML
Cc: Steven Rostedt, Mike Galbraith, Yong Zhang, Peter Zijlstra, Ingo Molnar
When pushing, if a pushable task could not be pushed, it is dequeued with no
updating the rt_nr_migratory element of RT run-queue, then rt_nr_migratory is
corrupted, which is fixed by removing the dequeue operation.
Signed-off-by: Hillf Danton <dhillf@gmail.com>
---
kernel/sched_rt.c | 5 +++--
1 files changed, 3 insertions(+), 2 deletions(-)
diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c
index 88725c9..496e06a 100644
--- a/kernel/sched_rt.c
+++ b/kernel/sched_rt.c
@@ -1378,6 +1378,7 @@ static int push_rt_task(struct rq *rq)
{
struct task_struct *next_task;
struct rq *lowest_rq;
+ int ret = 1;
if (!rq->rt.overloaded)
return 0;
@@ -1425,7 +1426,7 @@ retry:
* since the other cpus will pull from us when they
* are ready.
*/
- dequeue_pushable_task(rq, next_task);
+ ret = 0;
goto out;
}
@@ -1452,7 +1453,7 @@ retry:
out:
put_task_struct(next_task);
- return 1;
+ return ret;
}
static void push_rt_tasks(struct rq *rq)
^ permalink raw reply related [flat|nested] 8+ messages in thread
* Re: [PATCH] sched: fix rt_nr_migratory corruption raised in push_rt_task()
2011-05-30 13:39 [PATCH] sched: fix rt_nr_migratory corruption raised in push_rt_task() Hillf Danton
@ 2011-05-31 7:36 ` Mike Galbraith
2011-05-31 13:56 ` Hillf Danton
0 siblings, 1 reply; 8+ messages in thread
From: Mike Galbraith @ 2011-05-31 7:36 UTC (permalink / raw)
To: Hillf Danton
Cc: LKML, Steven Rostedt, Yong Zhang, Peter Zijlstra, Ingo Molnar
On Mon, 2011-05-30 at 21:39 +0800, Hillf Danton wrote:
> When pushing, if a pushable task could not be pushed, it is dequeued with no
> updating the rt_nr_migratory element of RT run-queue, then rt_nr_migratory is
> corrupted, which is fixed by removing the dequeue operation.
Hm. I think you're right that this dequeue_pushable_task() call can be
removed, at least I didn't see it's reason for existing. I'd word it a
bit differently though, and not return 1 unless we really did push.
From: Hillf Danton <dhillf@gmail.com>
sched, rt: fix rq->rt.pushable_tasks bug in push_rt_task()
Do not call dequeue_pushable_task() when failing to push an eligible
task, as it remains pushable, merely not at this particular moment.
Signed-off-by: Hillf Danton <dhillf@gmail.com>
---
kernel/sched_rt.c | 15 ++++++++-------
1 file changed, 8 insertions(+), 7 deletions(-)
Index: linux-2.6.40.git/kernel/sched_rt.c
===================================================================
--- linux-2.6.40.git.orig/kernel/sched_rt.c
+++ linux-2.6.40.git/kernel/sched_rt.c
@@ -1378,6 +1378,7 @@ static int push_rt_task(struct rq *rq)
{
struct task_struct *next_task;
struct rq *lowest_rq;
+ int ret = 0;
if (!rq->rt.overloaded)
return 0;
@@ -1410,7 +1411,7 @@ retry:
if (!lowest_rq) {
struct task_struct *task;
/*
- * find lock_lowest_rq releases rq->lock
+ * find_lock_lowest_rq releases rq->lock
* so it is possible that next_task has migrated.
*
* We need to make sure that the task is still on the same
@@ -1420,12 +1421,11 @@ retry:
task = pick_next_pushable_task(rq);
if (task_cpu(next_task) == rq->cpu && task == next_task) {
/*
- * If we get here, the task hasn't moved at all, but
- * it has failed to push. We will not try again,
- * since the other cpus will pull from us when they
- * are ready.
+ * The task hasn't migrated, and is still the next
+ * eligible task, but we failed to find a run-queue
+ * to push it to. Do not retry in this case, since
+ * other cpus will pull from us when ready.
*/
- dequeue_pushable_task(rq, next_task);
goto out;
}
@@ -1444,6 +1444,7 @@ retry:
deactivate_task(rq, next_task, 0);
set_task_cpu(next_task, lowest_rq->cpu);
activate_task(lowest_rq, next_task, 0);
+ ret = 1;
resched_task(lowest_rq->curr);
@@ -1452,7 +1453,7 @@ retry:
out:
put_task_struct(next_task);
- return 1;
+ return ret;
}
static void push_rt_tasks(struct rq *rq)
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] sched: fix rt_nr_migratory corruption raised in push_rt_task()
2011-05-31 7:36 ` Mike Galbraith
@ 2011-05-31 13:56 ` Hillf Danton
2011-05-31 15:08 ` Steven Rostedt
2011-06-01 2:21 ` [PATCH] sched: fix rt_nr_migratory corruption raised " Mike Galbraith
0 siblings, 2 replies; 8+ messages in thread
From: Hillf Danton @ 2011-05-31 13:56 UTC (permalink / raw)
To: Mike Galbraith
Cc: LKML, Steven Rostedt, Yong Zhang, Peter Zijlstra, Ingo Molnar
On Tue, May 31, 2011 at 3:36 PM, Mike Galbraith <efault@gmx.de> wrote:
> On Mon, 2011-05-30 at 21:39 +0800, Hillf Danton wrote:
>> When pushing, if a pushable task could not be pushed, it is dequeued with no
>> updating the rt_nr_migratory element of RT run-queue, then rt_nr_migratory is
>> corrupted, which is fixed by removing the dequeue operation.
>
> Hm. I think you're right that this dequeue_pushable_task() call can be
> removed, at least I didn't see it's reason for existing. I'd word it a
> bit differently though, and not return 1 unless we really did push.
>
Hi Mike
Your message shows what is called professional work, but something lost,
> From: Hillf Danton <dhillf@gmail.com>
>
> sched, rt: fix rq->rt.pushable_tasks bug in push_rt_task()
>
> Do not call dequeue_pushable_task() when failing to push an eligible
> task, as it remains pushable, merely not at this particular moment.
>
> Signed-off-by: Hillf Danton <dhillf@gmail.com>
Signed-off-by: Mike Galbraith <efault@gmx.de>
right?
> ---
> kernel/sched_rt.c | 15 ++++++++-------
> 1 file changed, 8 insertions(+), 7 deletions(-)
>
> Index: linux-2.6.40.git/kernel/sched_rt.c
> ===================================================================
And how to drive git to print the above two lines?
thanks
Hillf
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] sched: fix rt_nr_migratory corruption raised in push_rt_task()
2011-05-31 13:56 ` Hillf Danton
@ 2011-05-31 15:08 ` Steven Rostedt
2011-06-01 2:14 ` [PATCH] sched, rt: fix rq->rt.pushable_tasks bug " Mike Galbraith
2011-06-01 2:21 ` [PATCH] sched: fix rt_nr_migratory corruption raised " Mike Galbraith
1 sibling, 1 reply; 8+ messages in thread
From: Steven Rostedt @ 2011-05-31 15:08 UTC (permalink / raw)
To: Hillf Danton
Cc: Mike Galbraith, LKML, Yong Zhang, Peter Zijlstra, Ingo Molnar
On Tue, 2011-05-31 at 21:56 +0800, Hillf Danton wrote:
> On Tue, May 31, 2011 at 3:36 PM, Mike Galbraith <efault@gmx.de> wrote:
> > On Mon, 2011-05-30 at 21:39 +0800, Hillf Danton wrote:
> >> When pushing, if a pushable task could not be pushed, it is dequeued with no
> >> updating the rt_nr_migratory element of RT run-queue, then rt_nr_migratory is
> >> corrupted, which is fixed by removing the dequeue operation.
> >
> > Hm. I think you're right that this dequeue_pushable_task() call can be
> > removed, at least I didn't see it's reason for existing. I'd word it a
> > bit differently though, and not return 1 unless we really did push.
> >
>
> Hi Mike
>
> Your message shows what is called professional work, but something lost,
>
> > From: Hillf Danton <dhillf@gmail.com>
> >
> > sched, rt: fix rq->rt.pushable_tasks bug in push_rt_task()
> >
> > Do not call dequeue_pushable_task() when failing to push an eligible
> > task, as it remains pushable, merely not at this particular moment.
> >
> > Signed-off-by: Hillf Danton <dhillf@gmail.com>
>
> Signed-off-by: Mike Galbraith <efault@gmx.de>
>
Yeah, Mike, can you remail this adding your SOB too. You can keep
Hillf's SOB as well, since both of you made changes.
Thanks!
-- Steve
^ permalink raw reply [flat|nested] 8+ messages in thread
* [PATCH] sched, rt: fix rq->rt.pushable_tasks bug in push_rt_task()
2011-05-31 15:08 ` Steven Rostedt
@ 2011-06-01 2:14 ` Mike Galbraith
2011-06-01 2:29 ` Mike Galbraith
0 siblings, 1 reply; 8+ messages in thread
From: Mike Galbraith @ 2011-06-01 2:14 UTC (permalink / raw)
To: Steven Rostedt
Cc: Hillf Danton, LKML, Yong Zhang, Peter Zijlstra, Ingo Molnar
On Tue, 2011-05-31 at 11:08 -0400, Steven Rostedt wrote:
> On Tue, 2011-05-31 at 21:56 +0800, Hillf Danton wrote:
> > On Tue, May 31, 2011 at 3:36 PM, Mike Galbraith <efault@gmx.de> wrote:
> > > On Mon, 2011-05-30 at 21:39 +0800, Hillf Danton wrote:
> > >> When pushing, if a pushable task could not be pushed, it is dequeued with no
> > >> updating the rt_nr_migratory element of RT run-queue, then rt_nr_migratory is
> > >> corrupted, which is fixed by removing the dequeue operation.
> > >
> > > Hm. I think you're right that this dequeue_pushable_task() call can be
> > > removed, at least I didn't see it's reason for existing. I'd word it a
> > > bit differently though, and not return 1 unless we really did push.
> > >
> >
> > Hi Mike
> >
> > Your message shows what is called professional work, but something lost,
> >
> > > From: Hillf Danton <dhillf@gmail.com>
> > >
> > > sched, rt: fix rq->rt.pushable_tasks bug in push_rt_task()
> > >
> > > Do not call dequeue_pushable_task() when failing to push an eligible
> > > task, as it remains pushable, merely not at this particular moment.
> > >
> > > Signed-off-by: Hillf Danton <dhillf@gmail.com>
> >
> > Signed-off-by: Mike Galbraith <efault@gmx.de>
> >
>
> Yeah, Mike, can you remail this adding your SOB too. You can keep
> Hillf's SOB as well, since both of you made changes.
From: Hillf Danton <dhillf@gmail.com>
AuthorDate: Mon, 30 May 2011 21:39:50 +0800
sched, rt: fix rq->rt.pushable_tasks bug in push_rt_task()
Do not call dequeue_pushable_task() when failing to push an eligible
task, as it remains pushable until either it's cpumask says otherwise,
or is selected. It is merely not pushable at this particular moment.
Signed-off-by: Hillf Danton <dhillf@gmail.com>
Signed-off-by: Mike Galbraith <efault@gmx.de>
---
kernel/sched_rt.c | 15 ++++++++-------
1 file changed, 8 insertions(+), 7 deletions(-)
Index: linux-2.6.40.git/kernel/sched_rt.c
===================================================================
--- linux-2.6.40.git.orig/kernel/sched_rt.c
+++ linux-2.6.40.git/kernel/sched_rt.c
@@ -1378,6 +1378,7 @@ static int push_rt_task(struct rq *rq)
{
struct task_struct *next_task;
struct rq *lowest_rq;
+ int ret = 0;
if (!rq->rt.overloaded)
return 0;
@@ -1410,7 +1411,7 @@ retry:
if (!lowest_rq) {
struct task_struct *task;
/*
- * find lock_lowest_rq releases rq->lock
+ * find_lock_lowest_rq releases rq->lock
* so it is possible that next_task has migrated.
*
* We need to make sure that the task is still on the same
@@ -1420,12 +1421,11 @@ retry:
task = pick_next_pushable_task(rq);
if (task_cpu(next_task) == rq->cpu && task == next_task) {
/*
- * If we get here, the task hasn't moved at all, but
- * it has failed to push. We will not try again,
- * since the other cpus will pull from us when they
- * are ready.
+ * The task hasn't migrated, and is still the next
+ * eligible task, but we failed to find a run-queue
+ * to push it to. Do not retry in this case, since
+ * other cpus will pull from us when ready.
*/
- dequeue_pushable_task(rq, next_task);
goto out;
}
@@ -1444,6 +1444,7 @@ retry:
deactivate_task(rq, next_task, 0);
set_task_cpu(next_task, lowest_rq->cpu);
activate_task(lowest_rq, next_task, 0);
+ ret = 1;
resched_task(lowest_rq->curr);
@@ -1452,7 +1453,7 @@ retry:
out:
put_task_struct(next_task);
- return 1;
+ return ret;
}
static void push_rt_tasks(struct rq *rq)
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] sched: fix rt_nr_migratory corruption raised in push_rt_task()
2011-05-31 13:56 ` Hillf Danton
2011-05-31 15:08 ` Steven Rostedt
@ 2011-06-01 2:21 ` Mike Galbraith
1 sibling, 0 replies; 8+ messages in thread
From: Mike Galbraith @ 2011-06-01 2:21 UTC (permalink / raw)
To: Hillf Danton
Cc: LKML, Steven Rostedt, Yong Zhang, Peter Zijlstra, Ingo Molnar
On Tue, 2011-05-31 at 21:56 +0800, Hillf Danton wrote:
> On Tue, May 31, 2011 at 3:36 PM, Mike Galbraith <efault@gmx.de> wrote:
> > On Mon, 2011-05-30 at 21:39 +0800, Hillf Danton wrote:
> >> When pushing, if a pushable task could not be pushed, it is dequeued with no
> >> updating the rt_nr_migratory element of RT run-queue, then rt_nr_migratory is
> >> corrupted, which is fixed by removing the dequeue operation.
> >
> > Hm. I think you're right that this dequeue_pushable_task() call can be
> > removed, at least I didn't see it's reason for existing. I'd word it a
> > bit differently though, and not return 1 unless we really did push.
> >
>
> Hi Mike
>
> Your message shows what is called professional work, but something lost,
>
> > From: Hillf Danton <dhillf@gmail.com>
> >
> > sched, rt: fix rq->rt.pushable_tasks bug in push_rt_task()
> >
> > Do not call dequeue_pushable_task() when failing to push an eligible
> > task, as it remains pushable, merely not at this particular moment.
> >
> > Signed-off-by: Hillf Danton <dhillf@gmail.com>
>
> Signed-off-by: Mike Galbraith <efault@gmx.de>
>
> right?
Well, you did the legwork, but I resent it as requested.
> > ---
> > kernel/sched_rt.c | 15 ++++++++-------
> > 1 file changed, 8 insertions(+), 7 deletions(-)
> >
> > Index: linux-2.6.40.git/kernel/sched_rt.c
> > ===================================================================
>
> And how to drive git to print the above two lines?
That's easy, I used quilt :) I'm no master of git-fu (wimpy whitebelt),
use git for hunting, but quilt for twiddling.
-Mike
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] sched, rt: fix rq->rt.pushable_tasks bug in push_rt_task()
2011-06-01 2:14 ` [PATCH] sched, rt: fix rq->rt.pushable_tasks bug " Mike Galbraith
@ 2011-06-01 2:29 ` Mike Galbraith
2011-08-14 16:02 ` [tip:sched/core] sched, rt: Fix " tip-bot for Hillf Danton
0 siblings, 1 reply; 8+ messages in thread
From: Mike Galbraith @ 2011-06-01 2:29 UTC (permalink / raw)
To: Steven Rostedt
Cc: Hillf Danton, LKML, Yong Zhang, Peter Zijlstra, Ingo Molnar
Stupid mouse (driver) grabbed wrong text blob.
From: Hillf Danton <dhillf@gmail.com>
sched, rt: fix rq->rt.pushable_tasks bug in push_rt_task()
Do not call dequeue_pushable_task() when failing to push an eligible
task, as it remains pushable, merely not at this particular moment.
Signed-off-by: Hillf Danton <dhillf@gmail.com>
Signed-off-by: Mike Galbraith <mgalbraith@gmx.de>
---
kernel/sched_rt.c | 15 ++++++++-------
1 file changed, 8 insertions(+), 7 deletions(-)
Index: linux-2.6.40.git/kernel/sched_rt.c
===================================================================
--- linux-2.6.40.git.orig/kernel/sched_rt.c
+++ linux-2.6.40.git/kernel/sched_rt.c
@@ -1378,6 +1378,7 @@ static int push_rt_task(struct rq *rq)
{
struct task_struct *next_task;
struct rq *lowest_rq;
+ int ret = 0;
if (!rq->rt.overloaded)
return 0;
@@ -1410,7 +1411,7 @@ retry:
if (!lowest_rq) {
struct task_struct *task;
/*
- * find lock_lowest_rq releases rq->lock
+ * find_lock_lowest_rq releases rq->lock
* so it is possible that next_task has migrated.
*
* We need to make sure that the task is still on the same
@@ -1420,12 +1421,11 @@ retry:
task = pick_next_pushable_task(rq);
if (task_cpu(next_task) == rq->cpu && task == next_task) {
/*
- * If we get here, the task hasn't moved at all, but
- * it has failed to push. We will not try again,
- * since the other cpus will pull from us when they
- * are ready.
+ * The task hasn't migrated, and is still the next
+ * eligible task, but we failed to find a run-queue
+ * to push it to. Do not retry in this case, since
+ * other cpus will pull from us when ready.
*/
- dequeue_pushable_task(rq, next_task);
goto out;
}
@@ -1444,6 +1444,7 @@ retry:
deactivate_task(rq, next_task, 0);
set_task_cpu(next_task, lowest_rq->cpu);
activate_task(lowest_rq, next_task, 0);
+ ret = 1;
resched_task(lowest_rq->curr);
@@ -1452,7 +1453,7 @@ retry:
out:
put_task_struct(next_task);
- return 1;
+ return ret;
}
static void push_rt_tasks(struct rq *rq)
^ permalink raw reply [flat|nested] 8+ messages in thread
* [tip:sched/core] sched, rt: Fix rq->rt.pushable_tasks bug in push_rt_task()
2011-06-01 2:29 ` Mike Galbraith
@ 2011-08-14 16:02 ` tip-bot for Hillf Danton
0 siblings, 0 replies; 8+ messages in thread
From: tip-bot for Hillf Danton @ 2011-08-14 16:02 UTC (permalink / raw)
To: linux-tip-commits
Cc: linux-kernel, hpa, mingo, a.p.zijlstra, dhillf, mgalbraith,
rostedt, tglx, yong.zhang0, mingo
Commit-ID: 311e800e16f63d909136a64ed17ca353a160be59
Gitweb: http://git.kernel.org/tip/311e800e16f63d909136a64ed17ca353a160be59
Author: Hillf Danton <dhillf@gmail.com>
AuthorDate: Thu, 16 Jun 2011 21:55:20 -0400
Committer: Ingo Molnar <mingo@elte.hu>
CommitDate: Sun, 14 Aug 2011 12:00:48 +0200
sched, rt: Fix rq->rt.pushable_tasks bug in push_rt_task()
Do not call dequeue_pushable_task() when failing to push an eligible
task, as it remains pushable, merely not at this particular moment.
Signed-off-by: Hillf Danton <dhillf@gmail.com>
Signed-off-by: Mike Galbraith <mgalbraith@gmx.de>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Yong Zhang <yong.zhang0@gmail.com>
Link: http://lkml.kernel.org/r/1306895385.4791.26.camel@marge.simson.net
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
kernel/sched_rt.c | 15 ++++++++-------
1 files changed, 8 insertions(+), 7 deletions(-)
diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c
index e2698c0..8e18945 100644
--- a/kernel/sched_rt.c
+++ b/kernel/sched_rt.c
@@ -1394,6 +1394,7 @@ static int push_rt_task(struct rq *rq)
{
struct task_struct *next_task;
struct rq *lowest_rq;
+ int ret = 0;
if (!rq->rt.overloaded)
return 0;
@@ -1426,7 +1427,7 @@ retry:
if (!lowest_rq) {
struct task_struct *task;
/*
- * find lock_lowest_rq releases rq->lock
+ * find_lock_lowest_rq releases rq->lock
* so it is possible that next_task has migrated.
*
* We need to make sure that the task is still on the same
@@ -1436,12 +1437,11 @@ retry:
task = pick_next_pushable_task(rq);
if (task_cpu(next_task) == rq->cpu && task == next_task) {
/*
- * If we get here, the task hasn't moved at all, but
- * it has failed to push. We will not try again,
- * since the other cpus will pull from us when they
- * are ready.
+ * The task hasn't migrated, and is still the next
+ * eligible task, but we failed to find a run-queue
+ * to push it to. Do not retry in this case, since
+ * other cpus will pull from us when ready.
*/
- dequeue_pushable_task(rq, next_task);
goto out;
}
@@ -1460,6 +1460,7 @@ retry:
deactivate_task(rq, next_task, 0);
set_task_cpu(next_task, lowest_rq->cpu);
activate_task(lowest_rq, next_task, 0);
+ ret = 1;
resched_task(lowest_rq->curr);
@@ -1468,7 +1469,7 @@ retry:
out:
put_task_struct(next_task);
- return 1;
+ return ret;
}
static void push_rt_tasks(struct rq *rq)
^ permalink raw reply related [flat|nested] 8+ messages in thread
end of thread, other threads:[~2011-08-14 16:03 UTC | newest]
Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2011-05-30 13:39 [PATCH] sched: fix rt_nr_migratory corruption raised in push_rt_task() Hillf Danton
2011-05-31 7:36 ` Mike Galbraith
2011-05-31 13:56 ` Hillf Danton
2011-05-31 15:08 ` Steven Rostedt
2011-06-01 2:14 ` [PATCH] sched, rt: fix rq->rt.pushable_tasks bug " Mike Galbraith
2011-06-01 2:29 ` Mike Galbraith
2011-08-14 16:02 ` [tip:sched/core] sched, rt: Fix " tip-bot for Hillf Danton
2011-06-01 2:21 ` [PATCH] sched: fix rt_nr_migratory corruption raised " Mike Galbraith
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