From: Linus Torvalds <torvalds@linux-foundation.org>
To: Miklos Szeredi <miklos@szeredi.hu>
Cc: akpm@linux-foundation.org, hughd@google.com,
gurudas.pai@oracle.com, lkml20101129@newton.leun.net,
rjw@sisk.pl, florian@mickler.org, trond.myklebust@fys.uio.no,
maciej.rutecki@gmail.com, linux-kernel@vger.kernel.org,
linux-mm@kvack.org
Subject: Re: [PATCH] mm: prevent concurrent unmap_mapping_range() on the same inode
Date: Wed, 23 Feb 2011 14:33:54 -0800 [thread overview]
Message-ID: <AANLkTimeihuzjgR2f7Avq2PJrCw1vZxtjh=wBPXO3aHP@mail.gmail.com> (raw)
In-Reply-To: <E1PsEA7-0007G0-29@pomaz-ex.szeredi.hu>
On Wed, Feb 23, 2011 at 4:49 AM, Miklos Szeredi <miklos@szeredi.hu> wrote:
>
> This resolves Bug 25822 listed in the regressions since 2.6.36 (though
> it's a bug much older than that, for some reason it only started
> triggering for people recently).
Gaah. I hate this patch. It is, in fact, a patch that makes me finally
think that the mm preemptibility is actually worth it, because then
i_mmap_lock turns into a mutex and makes the whole "drop the lock"
thing hopefully a thing of the past (see the patch "mm: Remove
i_mmap_mutex lockbreak").
Because as far as I can see, the only thing that makes this thing
needed in the first place is that horribly ugly "we drop i_mmap_lock
in the middle of random operations that really still need it".
That said, I don't really see any alternatives - I guess we can't
really just say "remove that crazy lock dropping". Even though I
really really really would like to.
Of course, we could also just decide that we should apply the mm
preemptibility series instead. Can people confirm that that fixes the
bug too?
Linus
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next prev parent reply other threads:[~2011-02-23 22:35 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-02-23 12:49 [PATCH] mm: prevent concurrent unmap_mapping_range() on the same inode Miklos Szeredi
2011-02-23 22:20 ` Hugh Dickins
2011-02-23 22:33 ` Linus Torvalds [this message]
2011-02-23 23:12 ` Hugh Dickins
2011-03-02 9:48 ` Peter Zijlstra
-- strict thread matches above, loose matches on Subject: below --
2011-01-20 12:30 Miklos Szeredi
2011-01-20 12:40 ` Christoph Hellwig
2011-01-20 14:13 ` Miklos Szeredi
2011-01-22 4:46 ` Hugh Dickins
2011-01-24 19:47 ` Miklos Szeredi
2011-01-27 4:19 ` Hugh Dickins
2011-02-08 10:30 ` Miklos Szeredi
2011-02-08 11:52 ` Gurudas Pai
2011-02-08 11:59 ` Miklos Szeredi
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