From: Christoph Lameter <cl@linux.com>
To: Hugh Dickins <hughd@google.com>
Cc: Pekka Enberg <penberg@kernel.org>,
Eric Dumazet <eric.dumazet@gmail.com>,
Andrew Morton <akpm@linux-foundation.org>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH next/mmotm] slub: partly fix freeze in __slab_free
Date: Wed, 13 Jul 2011 10:47:11 -0500 (CDT) [thread overview]
Message-ID: <alpine.DEB.2.00.1107131041170.29034@router.home> (raw)
In-Reply-To: <alpine.LSU.2.00.1107130357560.4184@sister.anvils>
On Wed, 13 Jul 2011, Hugh Dickins wrote:
> As I reported in Fengguang's more_io thread, I couldn't get this patch
> to apply, unsurprisingly to mmotm, more surprisingly to Pekka's for-next
> (which adds in the _count build fix). Did you try to tidy up the
> indentations a little in between?
Nope. There are multiple patches that fix up thing in mm_types now and
they need to be stacked. I will try to avoid that.
> At the bottom I've put the patch against mmotm which I started testing
> instead on ppc64 a few hours ago. It again seized up in __slab_free()
> after two and a half hours. So either I screwed up my transliteration
> of your patch, or your patch is still wrong. Please check mine out.
>
> Is yours actually tested on PowerPC or ARM, say? I wonder if you're
> making endianness or bitfield ordering assumptions; but I've made no
> attempt to work it out. Anything I can send you? Disassembly of
> __slab_free()?
No I dont have PowerPC or ARM here. The problem is that without the
cmpxchg_double we fall back to slab_lock/slab_unlock. That code is not
that well tested. It is also used for slub_debug and that is how I tested
it.
The patch looks fine. I suspect that the reason lies elsewhere.
__slab_free does not disable interrupts. The use of cmpxchg_double_slab
would have to disable them if it falls back to the pagelock. Sigh.
next prev parent reply other threads:[~2011-07-13 15:47 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-07-11 18:58 [PATCH next/mmotm] slub: partly fix freeze in __slab_free Hugh Dickins
2011-07-11 19:39 ` Eric Dumazet
2011-07-11 20:46 ` Hugh Dickins
2011-07-12 6:13 ` Pekka Enberg
2011-07-12 15:11 ` Christoph Lameter
2011-07-12 15:55 ` Christoph Lameter
2011-07-13 11:28 ` Hugh Dickins
2011-07-13 15:47 ` Christoph Lameter [this message]
2011-07-13 15:55 ` Christoph Lameter
2011-07-14 16:14 ` Hugh Dickins
2011-07-14 17:26 ` Christoph Lameter
2011-07-15 19:22 ` Hugh Dickins
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