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From: Ralf Baechle <ralf@linux-mips.org>
To: Manuel Lauss <manuel.lauss@googlemail.com>
Cc: Linux-MIPS <linux-mips@linux-mips.org>,
	Manuel Lauss <manuel.lauss@gmail.com>
Subject: Re: [PATCH v2] MIPS: Alchemy: fix dbdma ring destruction memory debugcheck.
Date: Thu, 28 Jan 2010 12:22:52 +0100	[thread overview]
Message-ID: <20100128112250.GA8043@linux-mips.org> (raw)
In-Reply-To: <f861ec6f1001280023n7753c77wfd626d731ddc690a@mail.gmail.com>

On Thu, Jan 28, 2010 at 09:23:56AM +0100, Manuel Lauss wrote:

> >> This fix is only necessary with the SLAB allocator and CONFIG_DEBUG_SLAB
> >> enabled;  non-debug SLAB, SLUB do return nicely aligned addresses,
> >> debug-enabled SLUB currently panics early in the boot process.
> >
> > Queued for 2.6.34 - should this also go into 2.6.33?
> 
> 2.6.33 and .32 at least.  That code has been in there since the dawn of 2.6;
> the fact that nobody has tripped over this so far means that noone build kernels
> with slab debugging (I tripped over this while looking for something else) or
> the slab allocator behaviour changed recently.

The behaviour of the slab has been like this as long as I can remember.
Cherrypicking into the -stable branches as I'm writing this.

> > Have you considered increasing the value ARCH_KMALLOC_MINALIGN which
> > defaults to 8?  Or your own slab cache of suitable alignment?  The latter
> > is more something for frequent allocations.
> 
> I have to admit I know nothing about Linux' memory management.  Are slab
> caches not affected by the what I presume are "guard bytes" inserted into
> the memory areas when slab debug is on?

When creating a slab cache an alignment for objects allocated from this
cache can be specified.

  Ralf

      parent reply	other threads:[~2010-01-28 11:22 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-01-26 19:39 [PATCH v2] MIPS: Alchemy: fix dbdma ring destruction memory debugcheck Manuel Lauss
2010-01-27 22:18 ` Ralf Baechle
2010-01-28  8:23   ` Manuel Lauss
2010-01-28  8:23     ` Manuel Lauss
2010-01-28 11:22     ` Ralf Baechle [this message]

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