From: Christoph Lameter <cl@linux.com>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
linux-mm <linux-mm@kvack.org>,
Andrew Morton <akpm@linux-foundation.org>,
Pekka Enberg <penberg@kernel.org>, Matt Mackall <mpm@selenic.com>,
Thomas Gleixner <tglx@linutronix.de>,
RT <linux-rt-users@vger.kernel.org>,
Clark Williams <clark@redhat.com>, John Kacur <jkacur@gmail.com>,
"Luis Claudio R. Goncalves" <lgoncalv@redhat.com>
Subject: Re: [RFC][PATCH v3] slub: Keep page and object in sync in slab_alloc_node()
Date: Fri, 18 Jan 2013 18:40:16 +0000 [thread overview]
Message-ID: <0000013c4ef61783-2778b0f1-fdc1-421b-9d3e-ccd68d528115-000000@email.amazonses.com> (raw)
In-Reply-To: <1358521791.7383.11.camel@gandalf.local.home>
On Fri, 18 Jan 2013, Steven Rostedt wrote:
> @@ -2337,7 +2337,10 @@ redo:
> * enabled. We may switch back and forth between cpus while
> * reading from one cpu area. That does not matter as long
> * as we end up on the original cpu again when doing the cmpxchg.
> + *
> + * But we need to sync the setting of page and object.
> */
> + preempt_disable();
> c = __this_cpu_ptr(s->cpu_slab);
>
> /*
> @@ -2347,10 +2350,14 @@ redo:
> * linked list in between.
> */
> tid = c->tid;
The fetching of the tid is the only critical thing here. If the tid is
retrieved from the right cpu then the cmpxchg will fail if any changes
occured to freelist or the page variable.
The tid can be retrieved without disabling preemption through
this_cpu_read().
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next prev parent reply other threads:[~2013-01-18 18:40 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-01-17 18:10 [RFC][PATCH] slub: Check for page NULL before doing the node_match check Steven Rostedt
2013-01-17 18:37 ` Steven Rostedt
2013-01-17 21:28 ` Christoph Lameter
2013-01-17 21:36 ` Eric Dumazet
2013-01-17 21:44 ` Steven Rostedt
2013-01-17 21:43 ` Steven Rostedt
2013-01-17 21:51 ` Christoph Lameter
2013-01-17 22:07 ` Steven Rostedt
2013-01-17 22:46 ` Steven Rostedt
2013-01-17 23:10 ` Steven Rostedt
2013-01-17 23:20 ` [RFC][PATCH] slub: Keep page and object in sync in slab_alloc_node() Steven Rostedt
2013-01-18 0:23 ` Steven Rostedt
2013-01-18 0:28 ` [RFC][PATCH v2] " Steven Rostedt
2013-01-18 4:42 ` Joonsoo Kim
2013-01-18 14:52 ` Christoph Lameter
2013-01-18 15:29 ` Steven Rostedt
2013-01-18 14:44 ` Christoph Lameter
2013-01-18 15:04 ` Steven Rostedt
2013-01-18 15:55 ` Steven Rostedt
2013-01-18 18:29 ` Christoph Lameter
2013-01-18 18:52 ` Steven Rostedt
2013-01-21 1:48 ` Christoph Lameter
2013-01-21 8:11 ` Joonsoo Kim
2013-01-21 12:19 ` Steven Rostedt
2013-01-18 18:23 ` Christoph Lameter
2013-01-18 15:09 ` [RFC][PATCH v3] " Steven Rostedt
2013-01-18 18:40 ` Christoph Lameter [this message]
2013-01-18 19:09 ` Eric Dumazet
2013-01-18 19:20 ` Steven Rostedt
2013-01-21 1:40 ` Christoph Lameter
2013-01-18 14:43 ` [RFC][PATCH] slub: Check for page NULL before doing the node_match check Christoph Lameter
[not found] ` <alpine.DEB.2.02.1301171547370.2774@gentwo.org>
2013-01-17 21:56 ` Christoph Lameter
2013-01-17 22:10 ` Steven Rostedt
2013-01-17 21:22 ` Christoph Lameter
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