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From: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
To: "Paul Menage" <menage@google.com>
Cc: "Andrew Morton" <akpm@linux-foundation.org>,
	"Ingo Molnar" <mingo@elte.hu>,
	containers@lists.linux-foundation.org,
	linux-kernel@vger.kernel.org, dmitry.adamushko@gmail.com
Subject: Re: [PATCH 2/2] CFS CGroup: Report usage
Date: Tue, 23 Oct 2007 22:11:24 +0530	[thread overview]
Message-ID: <20071023164124.GA4666@linux.vnet.ibm.com> (raw)
In-Reply-To: <6599ad830710222306m6a3e3f52k4daf501836c05274@mail.gmail.com>

On Mon, Oct 22, 2007 at 11:06:54PM -0700, Paul Menage wrote:
> > > +     for_each_possible_cpu(i) {
> > > +             unsigned long flags;
> > > +             spin_lock_irqsave(&tg->cfs_rq[i]->rq->lock, flags);
> >
> > Is the lock absolutely required here?
> 
> I'm not sure, I was hoping you or Ingo could comment on this. But some
> kind of locking seems to required at least on 32-bit platforms, since
> sum_exec_runtime is a 64-bit number.

I tend to agree abt 32-bit platforms requiring a lock to read the 64-bit
sum_exec_runtime field.

Ingo/Dmitry, what do you think? fs/proc/array.c:task_utime() is also
buggy in that case.

-- 
Regards,
vatsa

  parent reply	other threads:[~2007-10-23 16:29 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-10-23  0:49 Paul Menage
2007-10-23  2:40 ` Srivatsa Vaddagiri
2007-10-23  6:06   ` Paul Menage
2007-10-23  7:21     ` Paul Menage
2007-10-23  7:49       ` Balbir Singh
2007-10-23  7:53         ` Paul Menage
2007-10-23  7:57           ` Balbir Singh
2007-10-23  8:08             ` Paul Menage
2007-10-23 16:41     ` Srivatsa Vaddagiri [this message]
2007-10-23  3:17 ` Balbir Singh
2007-10-23  6:09   ` Paul Menage
2007-10-23 16:43 ` Srivatsa Vaddagiri
2007-10-23 16:47 ` Srivatsa Vaddagiri
2007-10-23 16:41   ` Paul Menage
2007-10-23 17:38     ` Srivatsa Vaddagiri
2007-10-24  2:28       ` Paul Menage
2007-10-24  4:39         ` Srivatsa Vaddagiri
2007-10-26  1:24           ` Paul Menage

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