From mboxrd@z Thu Jan  1 00:00:00 1970
From: Pekka Enberg <penberg@kernel.org>
Subject: Re: [RFC][PATCH] mm: Fix RLIMIT_MEMLOCK
Date: Thu, 30 May 2013 22:59:46 +0300
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To: Christoph Lameter <cl@linux.com>
Cc: Peter Zijlstra <peterz@infradead.org>, Al Viro <viro@zeniv.linux.org.uk>, Vince Weaver <vincent.weaver@maine.edu>, LKML <linux-kernel@vger.kernel.org>, Paul Mackerras <paulus@samba.org>, Ingo Molnar <mingo@redhat.com>, Arnaldo Carvalho de Melo <acme@ghostprotocols.net>, trinity@vger.kernel.org, Andrew Morton <akpm@linux-foundation.org>, Linus Torvalds <torvalds@linux-foundation.org>, roland@kernel.org, infinipath@qlogic.com, "linux-mm@kvack.org" <linux-mm@kvack.org>, linux-rdma@vger.kernel.org, Or Gerlitz <or.gerlitz@gmail.com>, Hugh Dickins <hughd@google.com>
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On Mon, 27 May 2013, Peter Zijlstra wrote:
>> Before your patch pinned was included in locked and thus RLIMIT_MEMLOCK
>> had a single resource counter. After your patch RLIMIT_MEMLOCK is
>> applied separately to both -- more or less.

On Tue, May 28, 2013 at 7:37 PM, Christoph Lameter <cl@linux.com> wrote:
> Before the patch the count was doubled since a single page was counted
> twice: Once because it was mlocked (marked with PG_mlock) and then again
> because it was also pinned (the refcount was increased). Two different things.

Pinned vs. mlocked counting isn't the problem here. You changed
RLIMIT_MEMLOCK userspace ABI and that needs to be restored. So the
question is how can we preserve the old RLIMIT_MEMLOCK semantics while
avoiding the double accounting issue.

                        Pekka

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Date: Thu, 30 May 2013 22:59:46 +0300
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Subject: Re: [RFC][PATCH] mm: Fix RLIMIT_MEMLOCK
From: Pekka Enberg <penberg@kernel.org>
To: Christoph Lameter <cl@linux.com>
Cc: Peter Zijlstra <peterz@infradead.org>, Al Viro <viro@zeniv.linux.org.uk>,
        Vince Weaver <vincent.weaver@maine.edu>,
        LKML <linux-kernel@vger.kernel.org>, Paul Mackerras <paulus@samba.org>,
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        trinity@vger.kernel.org, Andrew Morton <akpm@linux-foundation.org>,
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        infinipath@qlogic.com, "linux-mm@kvack.org" <linux-mm@kvack.org>,
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        Hugh Dickins <hughd@google.com>
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On Mon, 27 May 2013, Peter Zijlstra wrote:
>> Before your patch pinned was included in locked and thus RLIMIT_MEMLOCK
>> had a single resource counter. After your patch RLIMIT_MEMLOCK is
>> applied separately to both -- more or less.

On Tue, May 28, 2013 at 7:37 PM, Christoph Lameter <cl@linux.com> wrote:
> Before the patch the count was doubled since a single page was counted
> twice: Once because it was mlocked (marked with PG_mlock) and then again
> because it was also pinned (the refcount was increased). Two different things.

Pinned vs. mlocked counting isn't the problem here. You changed
RLIMIT_MEMLOCK userspace ABI and that needs to be restored. So the
question is how can we preserve the old RLIMIT_MEMLOCK semantics while
avoiding the double accounting issue.

                        Pekka