From: Andrew Morton <akpm@linux-foundation.org>
To: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Hugh Dickins <hughd@google.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Rik van Riel <riel@redhat.com>
Subject: Re: [PATCH] mm: fix page-faults detection in swap-token logic
Date: Mon, 29 Aug 2011 16:06:37 -0700 [thread overview]
Message-ID: <20110829160637.bfc86e63.akpm@linux-foundation.org> (raw)
In-Reply-To: <20110827083201.21854.56111.stgit@zurg>
On Sat, 27 Aug 2011 12:32:01 +0300
Konstantin Khlebnikov <khlebnikov@openvz.org> wrote:
> After commit v2.6.36-5896-gd065bd8 "mm: retry page fault when blocking on disk transfer"
> we usually wait in page-faults without mmap_sem held, so all swap-token logic was broken,
> because it based on using rwsem_is_locked(&mm->mmap_sem) as sign of in progress page-faults.
If I'm interpreting this correctly, the thrash-handling logic has been
effectively disabled for a year and nobody noticed.
> This patch adds to mm_struct atomic counter of in progress page-faults for mm with swap-token.
We desperately need to delete some code from mm/. This seems like a
great candidate. Someone prove me wrong?
WARNING: multiple messages have this Message-ID (diff)
From: Andrew Morton <akpm@linux-foundation.org>
To: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Hugh Dickins <hughd@google.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Rik van Riel <riel@redhat.com>
Subject: Re: [PATCH] mm: fix page-faults detection in swap-token logic
Date: Mon, 29 Aug 2011 16:06:37 -0700 [thread overview]
Message-ID: <20110829160637.bfc86e63.akpm@linux-foundation.org> (raw)
In-Reply-To: <20110827083201.21854.56111.stgit@zurg>
On Sat, 27 Aug 2011 12:32:01 +0300
Konstantin Khlebnikov <khlebnikov@openvz.org> wrote:
> After commit v2.6.36-5896-gd065bd8 "mm: retry page fault when blocking on disk transfer"
> we usually wait in page-faults without mmap_sem held, so all swap-token logic was broken,
> because it based on using rwsem_is_locked(&mm->mmap_sem) as sign of in progress page-faults.
If I'm interpreting this correctly, the thrash-handling logic has been
effectively disabled for a year and nobody noticed.
> This patch adds to mm_struct atomic counter of in progress page-faults for mm with swap-token.
We desperately need to delete some code from mm/. This seems like a
great candidate. Someone prove me wrong?
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next prev parent reply other threads:[~2011-08-29 23:07 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-08-27 9:32 [PATCH] mm: fix page-faults detection in swap-token logic Konstantin Khlebnikov
2011-08-27 9:32 ` Konstantin Khlebnikov
2011-08-29 23:06 ` Andrew Morton [this message]
2011-08-29 23:06 ` Andrew Morton
2012-04-06 21:14 ` Rik van Riel
2012-04-06 21:14 ` Rik van Riel
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