From: Marcelo Tosatti <marcelo.tosatti@cyclades.com>
To: Rik van Riel <riel@redhat.com>
Cc: linux-kernel@vger.kernel.org, Matt Domsch <Matt_Domsch@dell.com>,
Ernie Petrides <petrides@redhat.com>
Subject: Re: [PATCH] reserved buffers only for PF_MEMALLOC
Date: Tue, 10 Aug 2004 17:16:52 -0300 [thread overview]
Message-ID: <20040810201652.GF13509@logos.cnet> (raw)
In-Reply-To: <Pine.LNX.4.44.0408101310580.7156-100000@dhcp83-102.boston.redhat.com>
On Tue, Aug 10, 2004 at 01:20:24PM -0400, Rik van Riel wrote:
>
> The buffer allocation path in 2.4 has a long standing bug,
> where non-PF_MEMALLOC tasks can dig into the reserved pool
> in get_unused_buffer_head(). The following patch makes the
> reserved pool only accessible to PF_MEMALLOC tasks.
>
> Other processes will loop in create_buffers() - the only
> function that calls get_unused_buffer_head() - and will call
> try_to_free_pages(GFP_NOIO), freeing any buffer heads that
> have become freeable due to IO completion.
>
> Note that PF_MEMALLOC tasks will NOT do anything inside
> try_to_free_pages(), so it is needed that they are able to
> dig into the reserved buffer heads while other tasks are
> not.
Applied.
Matt, it would be really nice if you could run the workload
which triggers the deadlock on 2.4.27+Rik's patch.
Thanks guys!
next prev parent reply other threads:[~2004-08-10 21:24 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-08-10 17:20 [PATCH] reserved buffers only for PF_MEMALLOC Rik van Riel
2004-08-10 19:04 ` Marcelo Tosatti
2004-08-10 20:42 ` Matt Domsch
2004-08-10 19:50 ` Marcelo Tosatti
2004-08-10 20:59 ` Rik van Riel
2004-08-10 20:16 ` Marcelo Tosatti [this message]
2004-10-20 14:02 ` Matt Domsch
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