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From: David Howells <dhowells@redhat.com>
To: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: dhowells@redhat.com, Paul Mundt <lethal@linux-sh.org>,
	Mel Gorman <mel@csn.ul.ie>,
	Christoph Lameter <cl@linux-foundation.org>,
	KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
	Peter Zijlstra <a.p.zijlstra@chello.nl>,
	Nick Piggin <nickpiggin@yahoo.com.au>,
	Dave Hansen <dave@linux.vnet.ibm.com>,
	Lee Schermerhorn <Lee.Schermerhorn@hp.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: page allocator regression on nommu
Date: Tue, 01 Sep 2009 14:35:47 +0100	[thread overview]
Message-ID: <6126.1251812147@redhat.com> (raw)
In-Reply-To: <84144f020908310308i48790f78g5a7d73a60ea854f8@mail.gmail.com>

Pekka Enberg <penberg@cs.helsinki.fi> wrote:

> This looks to be a bug in nommu do_mmap_pgoff() error handling. I
> guess we shouldn't call __put_nommu_region() if add_nommu_region()
> hasn't been called?

We should to make sure the region gets cleaned up properly.  However, it will
go wrong if do_mmap_shared_file() or do_mmap_private() fail.  We should
perhaps call add_nommu_region() before doing the "set up the mapping" chunk -
we hold the region semaphore, so it shouldn't hurt anyone if we then have to
remove it again.

David

WARNING: multiple messages have this Message-ID (diff)
From: David Howells <dhowells@redhat.com>
To: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: dhowells@redhat.com, Paul Mundt <lethal@linux-sh.org>,
	Mel Gorman <mel@csn.ul.ie>,
	Christoph Lameter <cl@linux-foundation.org>,
	KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
	Peter Zijlstra <a.p.zijlstra@chello.nl>,
	Nick Piggin <nickpiggin@yahoo.com.au>,
	Dave Hansen <dave@linux.vnet.ibm.com>,
	Lee Schermerhorn <Lee.Schermerhorn@hp.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: page allocator regression on nommu
Date: Tue, 01 Sep 2009 14:35:47 +0100	[thread overview]
Message-ID: <6126.1251812147@redhat.com> (raw)
In-Reply-To: <84144f020908310308i48790f78g5a7d73a60ea854f8@mail.gmail.com>

Pekka Enberg <penberg@cs.helsinki.fi> wrote:

> This looks to be a bug in nommu do_mmap_pgoff() error handling. I
> guess we shouldn't call __put_nommu_region() if add_nommu_region()
> hasn't been called?

We should to make sure the region gets cleaned up properly.  However, it will
go wrong if do_mmap_shared_file() or do_mmap_private() fail.  We should
perhaps call add_nommu_region() before doing the "set up the mapping" chunk -
we hold the region semaphore, so it shouldn't hurt anyone if we then have to
remove it again.

David

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  parent reply	other threads:[~2009-09-01 13:36 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-08-31  7:48 page allocator regression on nommu Paul Mundt
2009-08-31  7:48 ` Paul Mundt
2009-08-31 10:08 ` Pekka Enberg
2009-08-31 10:08   ` Pekka Enberg
2009-08-31 10:26   ` Paul Mundt
2009-08-31 10:26     ` Paul Mundt
2009-09-01 13:46     ` David Howells
2009-09-01 13:46       ` David Howells
2009-09-01 13:48       ` Pekka Enberg
2009-09-01 13:48         ` Pekka Enberg
2009-09-01 14:27       ` Paul Mundt
2009-09-01 14:27         ` Paul Mundt
2009-09-01 13:35   ` David Howells [this message]
2009-09-01 13:35     ` David Howells
2009-08-31 10:30 ` Mel Gorman
2009-08-31 10:30   ` Mel Gorman
2009-08-31 10:43   ` Paul Mundt
2009-08-31 10:43     ` Paul Mundt
2009-08-31 10:59     ` Mel Gorman
2009-08-31 10:59       ` Mel Gorman
2009-09-01  0:46       ` Paul Mundt
2009-09-01  0:46         ` Paul Mundt
2009-09-01 10:03         ` Mel Gorman
2009-09-01 10:03           ` Mel Gorman
2009-09-01 10:20           ` Paul Mundt
2009-09-01 10:20             ` Paul Mundt

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