On 09/13, Peter Zijlstra wrote:
>
> On Tue, Sep 13, 2016 at 06:14:27PM +0200, Oleg Nesterov wrote:
>
> > Hmm. And preempt_enable_no_resched_notrace() under TASK_DEAD in
> > __schedule() should be removed it seems, do_exit() can call __schedule()
> > directly.
>
> something like so?
Yes, exactly.
On 09/13, Peter Zijlstra wrote:
>
> On Tue, Sep 13, 2016 at 06:14:27PM +0200, Oleg Nesterov wrote:
>
> > Hmm. And preempt_enable_no_resched_notrace() under TASK_DEAD in
> > __schedule() should be removed it seems, do_exit() can call __schedule()
> > directly.
>
> something like so?
Yes, exactly.
On Wed, Sep 14, 2016 at 10:07:14AM +0800, Cheng Chao wrote:
>
> great, __schedule() doesn't need pay any attention to the TASK_DEAD now.
There's still __schedule()->context_switch()->finish_task_switch().
On Wed, Sep 14, 2016 at 10:07:14AM +0800, Cheng Chao wrote:
>
> great, __schedule() doesn't need pay any attention to the TASK_DEAD now.
There's still __schedule()->context_switch()->finish_task_switch().
great, __schedule() doesn't need pay any attention to the TASK_DEAD now.
on 09/14/2016 12:37 AM, Peter Zijlstra wrote:
> On Tue, Sep 13, 2016 at 06:14:27PM +0200, Oleg Nesterov wrote:
>
>> Me too, and I failed to find something which could be broken... So
>> perhaps should make it nop and
great, __schedule() doesn't need pay any attention to the TASK_DEAD now.
on 09/14/2016 12:37 AM, Peter Zijlstra wrote:
> On Tue, Sep 13, 2016 at 06:14:27PM +0200, Oleg Nesterov wrote:
>
>> Me too, and I failed to find something which could be broken... So
>> perhaps should make it nop and
On Tue, Sep 13, 2016 at 06:14:27PM +0200, Oleg Nesterov wrote:
> Me too, and I failed to find something which could be broken... So
> perhaps should make it nop and investigate the new bug reports after
> that.
Works for me :-)
>
> Hmm. And preempt_enable_no_resched_notrace() under TASK_DEAD
On Tue, Sep 13, 2016 at 06:14:27PM +0200, Oleg Nesterov wrote:
> Me too, and I failed to find something which could be broken... So
> perhaps should make it nop and investigate the new bug reports after
> that.
Works for me :-)
>
> Hmm. And preempt_enable_no_resched_notrace() under TASK_DEAD
On 09/12, Peter Zijlstra wrote:
>
> On Mon, Sep 12, 2016 at 03:05:38PM +0200, Oleg Nesterov wrote:
>
> > But this leads to the question which I wanted to ask many times.
> >
> > Why cond_resched() is not NOP if CONFIG_PREEMPT=y ?
>
> Dunno, nobody bothered to do it? We should keep the
On 09/12, Peter Zijlstra wrote:
>
> On Mon, Sep 12, 2016 at 03:05:38PM +0200, Oleg Nesterov wrote:
>
> > But this leads to the question which I wanted to ask many times.
> >
> > Why cond_resched() is not NOP if CONFIG_PREEMPT=y ?
>
> Dunno, nobody bothered to do it? We should keep the
On Tue, Sep 13, 2016 at 12:03:05PM +0800, Cheng Chao wrote:
>
> Peter, Is it as a new patch?
I wanted both changes in one pathc, but I fudged my git-diff.
> > ---
> > kernel/stop_machine.c | 5 +
> > 1 file changed, 5 insertions(+)
> >
> > diff --git a/kernel/stop_machine.c
On Tue, Sep 13, 2016 at 12:03:05PM +0800, Cheng Chao wrote:
>
> Peter, Is it as a new patch?
I wanted both changes in one pathc, but I fudged my git-diff.
> > ---
> > kernel/stop_machine.c | 5 +
> > 1 file changed, 5 insertions(+)
> >
> > diff --git a/kernel/stop_machine.c
Peter, thank you.
on 09/12/2016 07:41 PM, Peter Zijlstra wrote:
> On Mon, Sep 12, 2016 at 01:37:27PM +0200, Peter Zijlstra wrote:
>> So what you're saying is that migration_stop_cpu() doesn't work because
>> wait_for_completion() dequeues the task.
>>
>> True I suppose. Not sure I like your
Peter, thank you.
on 09/12/2016 07:41 PM, Peter Zijlstra wrote:
> On Mon, Sep 12, 2016 at 01:37:27PM +0200, Peter Zijlstra wrote:
>> So what you're saying is that migration_stop_cpu() doesn't work because
>> wait_for_completion() dequeues the task.
>>
>> True I suppose. Not sure I like your
on 09/12/2016 07:03 PM, Oleg Nesterov wrote:
> On 09/10, Cheng Chao wrote:
>>
>> @@ -126,6 +126,17 @@ int stop_one_cpu(unsigned int cpu, cpu_stop_fn_t fn,
>> void *arg)
>> cpu_stop_init_done(, 1);
>> if (!cpu_stop_queue_work(cpu, ))
>> return -ENOENT;
>> +
>> +#if
on 09/12/2016 07:03 PM, Oleg Nesterov wrote:
> On 09/10, Cheng Chao wrote:
>>
>> @@ -126,6 +126,17 @@ int stop_one_cpu(unsigned int cpu, cpu_stop_fn_t fn,
>> void *arg)
>> cpu_stop_init_done(, 1);
>> if (!cpu_stop_queue_work(cpu, ))
>> return -ENOENT;
>> +
>> +#if
On Mon, Sep 12, 2016 at 03:05:38PM +0200, Oleg Nesterov wrote:
> But this leads to the question which I wanted to ask many times.
>
> Why cond_resched() is not NOP if CONFIG_PREEMPT=y ?
Dunno, nobody bothered to do it? We should keep the might_sleep() of
course, but the preemption check is
On Mon, Sep 12, 2016 at 03:05:38PM +0200, Oleg Nesterov wrote:
> But this leads to the question which I wanted to ask many times.
>
> Why cond_resched() is not NOP if CONFIG_PREEMPT=y ?
Dunno, nobody bothered to do it? We should keep the might_sleep() of
course, but the preemption check is
On 09/12, Peter Zijlstra wrote:
>
> --- a/kernel/stop_machine.c
> +++ b/kernel/stop_machine.c
> @@ -121,6 +121,11 @@ int stop_one_cpu(unsigned int cpu, cpu_stop_fn_t fn,
> void *arg)
> cpu_stop_init_done(, 1);
> if (!cpu_stop_queue_work(cpu, ))
> return -ENOENT;
> +
On 09/12, Peter Zijlstra wrote:
>
> --- a/kernel/stop_machine.c
> +++ b/kernel/stop_machine.c
> @@ -121,6 +121,11 @@ int stop_one_cpu(unsigned int cpu, cpu_stop_fn_t fn,
> void *arg)
> cpu_stop_init_done(, 1);
> if (!cpu_stop_queue_work(cpu, ))
> return -ENOENT;
> +
On Mon, Sep 12, 2016 at 01:37:27PM +0200, Peter Zijlstra wrote:
> So what you're saying is that migration_stop_cpu() doesn't work because
> wait_for_completion() dequeues the task.
>
> True I suppose. Not sure I like your solution, nor your implementation
> of the solution much though.
>
> I
On Mon, Sep 12, 2016 at 01:37:27PM +0200, Peter Zijlstra wrote:
> So what you're saying is that migration_stop_cpu() doesn't work because
> wait_for_completion() dequeues the task.
>
> True I suppose. Not sure I like your solution, nor your implementation
> of the solution much though.
>
> I
On Sat, Sep 10, 2016 at 04:52:12PM +0800, Cheng Chao wrote:
> For CONFIG_PREEMPT_NONE=y, when sched_exec() needs migration, sched_exec()
> calls stop_one_cpu(task_cpu(p), migration_cpu_stop, ).
>
> If the migration_cpu_stop() can not migrate,why do we call stop_one_cpu()?
> It just makes the task
On Sat, Sep 10, 2016 at 04:52:12PM +0800, Cheng Chao wrote:
> For CONFIG_PREEMPT_NONE=y, when sched_exec() needs migration, sched_exec()
> calls stop_one_cpu(task_cpu(p), migration_cpu_stop, ).
>
> If the migration_cpu_stop() can not migrate,why do we call stop_one_cpu()?
> It just makes the task
On 09/10, Cheng Chao wrote:
>
> @@ -126,6 +126,17 @@ int stop_one_cpu(unsigned int cpu, cpu_stop_fn_t fn,
> void *arg)
> cpu_stop_init_done(, 1);
> if (!cpu_stop_queue_work(cpu, ))
> return -ENOENT;
> +
> +#if defined(CONFIG_PREEMPT_NONE)
> + /*
> + * Makes the
On 09/10, Cheng Chao wrote:
>
> @@ -126,6 +126,17 @@ int stop_one_cpu(unsigned int cpu, cpu_stop_fn_t fn,
> void *arg)
> cpu_stop_init_done(, 1);
> if (!cpu_stop_queue_work(cpu, ))
> return -ENOENT;
> +
> +#if defined(CONFIG_PREEMPT_NONE)
> + /*
> + * Makes the
On Sat, Sep 10, 2016 at 05:51:02PM +0800, Cheng Chao wrote:
> hi Peter, I guess you can receive the mail from me now,
> I have changed the mailbox to gmail.
Indeed, I'll have a look on Monday.
On Sat, Sep 10, 2016 at 05:51:02PM +0800, Cheng Chao wrote:
> hi Peter, I guess you can receive the mail from me now,
> I have changed the mailbox to gmail.
Indeed, I'll have a look on Monday.
hi Peter, I guess you can receive the mail from me now,
I have changed the mailbox to gmail.
Oleg has already done much work for this patch, I am really obliged.
please review this patch, thanks.
on 09/10/2016 04:52 PM, Cheng Chao wrote:
> For CONFIG_PREEMPT_NONE=y, when sched_exec() needs
hi Peter, I guess you can receive the mail from me now,
I have changed the mailbox to gmail.
Oleg has already done much work for this patch, I am really obliged.
please review this patch, thanks.
on 09/10/2016 04:52 PM, Cheng Chao wrote:
> For CONFIG_PREEMPT_NONE=y, when sched_exec() needs
For CONFIG_PREEMPT_NONE=y, when sched_exec() needs migration, sched_exec()
calls stop_one_cpu(task_cpu(p), migration_cpu_stop, ).
If the migration_cpu_stop() can not migrate,why do we call stop_one_cpu()?
It just makes the task TASK_UNINTERRUPTIBLE, wakes up the stopper thread,
executes
For CONFIG_PREEMPT_NONE=y, when sched_exec() needs migration, sched_exec()
calls stop_one_cpu(task_cpu(p), migration_cpu_stop, ).
If the migration_cpu_stop() can not migrate,why do we call stop_one_cpu()?
It just makes the task TASK_UNINTERRUPTIBLE, wakes up the stopper thread,
executes
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