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From: Nick Piggin <npiggin@suse.de>
To: Pekka J Enberg <penberg@cs.helsinki.fi>
Cc: Theodore Tso <tytso@mit.edu>, Eric Sandeen <sandeen@redhat.com>,
	Andreas Dilger <adilger@sun.com>,
	David Rientjes <rientjes@google.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	arjan@infradead.org, linux-kernel@vger.kernel.org,
	cl@linux-foundation.org, linux-ext4@vger.kernel.org
Subject: Re: upcoming kerneloops.org item: get_page_from_freelist
Date: Fri, 26 Jun 2009 10:56:29 +0200	[thread overview]
Message-ID: <20090626085629.GC12201@wotan.suse.de> (raw)
In-Reply-To: <Pine.LNX.4.64.0906260815260.18724@melkki.cs.Helsinki.FI>

On Fri, Jun 26, 2009 at 08:16:18AM +0300, Pekka Enberg wrote:
> Hi Ted,
> 
> On Thu, Jun 25, 2009 at 05:11:25PM -0500, Eric Sandeen wrote:
> > > ecryptfs used to do kmalloc(PAGE_CACHE_SIZE) & virt_to_page on that, and
> > > with SLUB + slub debug, that gave back non-aligned memory, causing
> > > eventual corruption ...
> 
> On Thu, 25 Jun 2009, Theodore Tso wrote:
> > Grumble.  Any chance we could add an kmem_cache option which requires
> > the memory to be aligned?  Otherwise we could rewrite our own sub-page
> > allocator in ext4 that only handled aligned filesystem block sizes
> > (i.e., 1k, 2k, 4k, etc.) but that would be really silly and be extra
> > code that really should be done once at core functionality.
> 
> We alredy have SLAB_HW_ALIGN but I wonder if this is a plain old bug in 
> SLUB. Christoph, Nick, don't we need something like this in the allocator? 
> Eric, does this fix your case?

Well I don't understand Ted's complaint. kmem_cache_create takes an
alignment argument.


  reply	other threads:[~2009-06-26  8:56 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <alpine.LFD.2.01.0906241240360.3154@localhost.localdomain>
     [not found] ` <20090624130121.99321cca.akpm@linux-foundation.org>
     [not found]   ` <alpine.LFD.2.01.0906241312090.3154@localhost.localdomain>
     [not found]     ` <alpine.LFD.2.01.0906241334260.3154@localhost.localdomain>
     [not found]       ` <20090624150714.c7264768.akpm@linux-foundation.org>
     [not found]         ` <20090625132544.GB9995@mit.edu>
     [not found]           ` <alpine.DEB.2.00.0906251135440.30090@chino.kir.corp.google.com>
     [not found]             ` <20090625193806.GA6472@mit.edu>
     [not found]               ` <20090625194423.GB6472@mit.edu>
     [not found]                 ` <alpine.DEB.2.00.0906251257040.3086@chino.kir.corp.google.com>
2009-06-25 20:37                   ` upcoming kerneloops.org item: get_page_from_freelist Theodore Tso
2009-06-25 21:05                     ` Joel Becker
2009-06-25 21:26                     ` Andreas Dilger
2009-06-25 22:05                       ` Theodore Tso
2009-06-25 22:11                         ` Eric Sandeen
2009-06-26  1:11                           ` Theodore Tso
2009-06-26  5:16                             ` Pekka J Enberg
2009-06-26  8:56                               ` Nick Piggin [this message]
2009-06-26  8:58                                 ` Pekka Enberg
2009-06-26  9:07                                   ` Nick Piggin
2009-06-29 21:06                                   ` Christoph Lameter
2009-06-30  7:59                                     ` Nick Piggin
2009-06-26 14:41                               ` Eric Sandeen
2009-06-29 21:15                                 ` Christoph Lameter
2009-06-29 21:20                                   ` Eric Sandeen
2009-06-29 22:35                                     ` Christoph Lameter

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