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From: Christoph Lameter <cl@linux.com>
To: Brice Goglin <Brice.Goglin@inria.fr>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
	linux-mm@kvack.org, LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] migration: only migrate_prep() once per move_pages()
Date: Wed, 15 Apr 2009 08:41:38 -0400 (EDT)	[thread overview]
Message-ID: <alpine.DEB.1.10.0904150840450.10217@qirst.com> (raw)
In-Reply-To: <49E5A9DC.2050309@inria.fr>

On Wed, 15 Apr 2009, Brice Goglin wrote:

> But lru_add_drain_all() touches some code that I am far from
> understanding :/ Can we imagine using IPI instead of a deferred
> work_struct for this kind of things? Or maybe, for each processor, check
> whether drain_cpu_pagevecs() would have something to do before actually
> scheduling the local work_struct? It's racy, but migrate_prep() doesn't
> guarantee anyway that pages won't be moved out of the LRU before the
> actual migration, so...

IPI means that code must run with interrupts disabled.

> > BTW, current users of sys_move_pages() does retry when it gets -EBUSY ?
> >
>
> I'd say they ignore it since it doesn't happen often :)

Right.

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  reply	other threads:[~2009-04-15 12:48 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-04-15  7:32 Brice Goglin
2009-04-15  7:49 ` KAMEZAWA Hiroyuki
2009-04-15  9:33   ` Brice Goglin
2009-04-15 12:41     ` Christoph Lameter [this message]
2009-05-13  5:52   ` Brice Goglin
2009-05-14 20:11     ` Christoph Lameter

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