From: Christoph Lameter <cl@linux.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>,
Pekka Enberg <penberg@kernel.org>,
David Rientjes <rientjes@google.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Jesper Dangaard Brouer <brouer@redhat.com>,
rostedt@goodmis.org, Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH v2 2/2] mm: don't use compound_head() in virt_to_head_page()
Date: Thu, 15 Jan 2015 21:30:12 -0600 (CST) [thread overview]
Message-ID: <alpine.DEB.2.11.1501152128460.13976@gentwo.org> (raw)
In-Reply-To: <20150115171646.8fec31e2.akpm@linux-foundation.org>
On Thu, 15 Jan 2015, Andrew Morton wrote:
> And perhaps some explanation here as to why virt_to_head_page() can
> safely use compound_head_fast(). There's an assumption here that
> nobody will be dismantling the compound page while virt_to_head_page()
> is in progress, yes? And this assumption also holds for the calling
> code, because otherwise the virt_to_head_page() return value is kinda
> meaningless.
I think this assumption is pretty natural to make. A coupound_head that
works well while dismantling a compound page should be marked specially
and Joonsoo's definition should be the standard.
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next prev parent reply other threads:[~2015-01-16 3:30 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-01-15 7:40 [PATCH v2 1/2] mm/slub: optimize alloc/free fastpath by removing preemption on/off Joonsoo Kim
2015-01-15 7:40 ` [PATCH v2 2/2] mm: don't use compound_head() in virt_to_head_page() Joonsoo Kim
2015-01-16 1:16 ` Andrew Morton
2015-01-16 3:30 ` Christoph Lameter [this message]
2015-01-19 4:20 ` 答复: " Zhang, Yanfei
2015-01-19 6:16 ` Joonsoo Kim
2015-01-15 8:10 ` [PATCH v2 1/2] mm/slub: optimize alloc/free fastpath by removing preemption on/off Jesper Dangaard Brouer
2015-01-16 1:16 ` Andrew Morton
2015-01-16 1:30 ` Steven Rostedt
2015-01-16 3:27 ` Christoph Lameter
2015-01-16 3:51 ` Steven Rostedt
2015-01-16 3:57 ` Christoph Lameter
2015-01-16 4:07 ` Steven Rostedt
2015-01-16 13:40 ` Eric Dumazet
2015-01-16 16:37 ` Steven Rostedt
2015-01-16 4:04 ` Steven Rostedt
2015-01-16 3:28 ` Christoph Lameter
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