From: Peter Zijlstra <peterz@infradead.org>
To: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Michel Lespinasse <walken@google.com>,
linux-mm <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>,
Divyesh Shah <dpshah@google.com>
Subject: Re: FYI: mmap_sem OOM patch
Date: Thu, 08 Jul 2010 11:35:17 +0200 [thread overview]
Message-ID: <1278581717.1900.20.camel@laptop> (raw)
In-Reply-To: <20100708182134.CD3F.A69D9226@jp.fujitsu.com>
On Thu, 2010-07-08 at 18:24 +0900, KOSAKI Motohiro wrote:
> > On Wed, 2010-07-07 at 16:11 -0700, Michel Lespinasse wrote:
> >
> > > diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
> > > index f627779..4b3a1c7 100644
> > > --- a/arch/x86/mm/fault.c
> > > +++ b/arch/x86/mm/fault.c
> > > @@ -1062,7 +1062,10 @@ do_page_fault(struct pt_regs *regs, unsigned long error_code)
> > > bad_area_nosemaphore(regs, error_code, address);
> > > return;
> > > }
> > > - down_read(&mm->mmap_sem);
> > > + if (test_thread_flag(TIF_MEMDIE))
> > > + down_read_unfair(&mm->mmap_sem);
> > > + else
> > > + down_read(&mm->mmap_sem);
> > > } else {
> > > /*
> > > * The above down_read_trylock() might have succeeded in
> >
> > I still think adding that _unfair interface is asking for trouble.
>
> Can you please explain trouble that you worry? Why do we need to keep
> thread fairness when OOM case?
Just the whole concept of the unfair thing offends me ;-) I didn't
really look at the particular application in this case.
WARNING: multiple messages have this Message-ID (diff)
From: Peter Zijlstra <peterz@infradead.org>
To: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Michel Lespinasse <walken@google.com>,
linux-mm <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>,
Divyesh Shah <dpshah@google.com>
Subject: Re: FYI: mmap_sem OOM patch
Date: Thu, 08 Jul 2010 11:35:17 +0200 [thread overview]
Message-ID: <1278581717.1900.20.camel@laptop> (raw)
In-Reply-To: <20100708182134.CD3F.A69D9226@jp.fujitsu.com>
On Thu, 2010-07-08 at 18:24 +0900, KOSAKI Motohiro wrote:
> > On Wed, 2010-07-07 at 16:11 -0700, Michel Lespinasse wrote:
> >
> > > diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
> > > index f627779..4b3a1c7 100644
> > > --- a/arch/x86/mm/fault.c
> > > +++ b/arch/x86/mm/fault.c
> > > @@ -1062,7 +1062,10 @@ do_page_fault(struct pt_regs *regs, unsigned long error_code)
> > > bad_area_nosemaphore(regs, error_code, address);
> > > return;
> > > }
> > > - down_read(&mm->mmap_sem);
> > > + if (test_thread_flag(TIF_MEMDIE))
> > > + down_read_unfair(&mm->mmap_sem);
> > > + else
> > > + down_read(&mm->mmap_sem);
> > > } else {
> > > /*
> > > * The above down_read_trylock() might have succeeded in
> >
> > I still think adding that _unfair interface is asking for trouble.
>
> Can you please explain trouble that you worry? Why do we need to keep
> thread fairness when OOM case?
Just the whole concept of the unfair thing offends me ;-) I didn't
really look at the particular application in this case.
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next prev parent reply other threads:[~2010-07-08 9:35 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-07-07 23:11 FYI: mmap_sem OOM patch Michel Lespinasse
2010-07-07 23:11 ` Michel Lespinasse
2010-07-08 0:16 ` KOSAKI Motohiro
2010-07-08 0:16 ` KOSAKI Motohiro
2010-07-08 1:11 ` KOSAKI Motohiro
2010-07-08 1:11 ` KOSAKI Motohiro
2010-07-08 9:02 ` Peter Zijlstra
2010-07-08 9:02 ` Peter Zijlstra
2010-07-08 9:24 ` KOSAKI Motohiro
2010-07-08 9:24 ` KOSAKI Motohiro
2010-07-08 9:35 ` Peter Zijlstra [this message]
2010-07-08 9:35 ` Peter Zijlstra
2010-07-08 9:51 ` KOSAKI Motohiro
2010-07-08 9:51 ` KOSAKI Motohiro
2010-07-08 10:30 ` Peter Zijlstra
2010-07-08 10:30 ` Peter Zijlstra
[not found] ` <AANLkTimLSnNot2byTWYuIHE8rhGLXbl1zKsQQhmci1Do@mail.gmail.com>
2010-07-08 10:49 ` Peter Zijlstra
2010-07-08 10:49 ` Peter Zijlstra
2010-07-08 10:57 ` KOSAKI Motohiro
2010-07-08 10:57 ` KOSAKI Motohiro
2010-07-08 11:02 ` Peter Zijlstra
2010-07-08 11:02 ` Peter Zijlstra
2010-07-08 11:06 ` KOSAKI Motohiro
2010-07-08 11:06 ` KOSAKI Motohiro
2010-07-08 11:23 ` Peter Zijlstra
2010-07-08 11:23 ` Peter Zijlstra
2010-07-09 1:31 ` KOSAKI Motohiro
2010-07-09 1:31 ` KOSAKI Motohiro
2010-07-12 21:47 ` David Rientjes
2010-07-12 21:47 ` David Rientjes
2010-07-13 0:14 ` KOSAKI Motohiro
2010-07-13 0:14 ` KOSAKI Motohiro
2010-07-13 21:08 ` David Rientjes
2010-07-13 21:08 ` David Rientjes
[not found] ` <AANLkTimArLPHrxHNEejiXKNYk9To6qsjglbgzyypXP-c@mail.gmail.com>
2010-07-08 12:43 ` Peter Zijlstra
2010-07-08 12:43 ` Peter Zijlstra
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