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From: Eric Sandeen <sandeen@redhat.com>
To: Theodore Tso <tytso@mit.edu>, Andreas Dilger <adilger@sun.com>,
	David Rientjes <rientjes@google.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Linus Torvalds <torvalds@linux-foundat
Subject: Re: upcoming kerneloops.org item: get_page_from_freelist
Date: Thu, 25 Jun 2009 17:11:25 -0500	[thread overview]
Message-ID: <4A43F60D.2040801@redhat.com> (raw)
In-Reply-To: <20090625220504.GG6472@mit.edu>

Theodore Tso wrote:
> On Thu, Jun 25, 2009 at 11:26:28PM +0200, Andreas Dilger wrote:
>> IIRC there was also a good reason for this in the past, related to
>> the buffers being submitted to the block device layer, and if they
>> were allocated from the slab cache with CONFIG_DEBUG_SLAB or something
>> similar enabled the buffer would be misaligned and cause grief.
> 
> So what does SLAB/SLUB/SLOB do if we create a slab cache which is a
> power of two?  Can one of the allocators still return misaligned
> blocks of memory in some circumstances?
> 
> 						- Ted

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 ...

-Eric


  reply	other threads:[~2009-06-25 22:12 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 [this message]
2009-06-26  1:11                           ` Theodore Tso
2009-06-26  5:16                             ` Pekka J Enberg
2009-06-26  8:56                               ` Nick Piggin
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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