From: Andrew Morton <akpm@osdl.org>
To: Christoph Lameter <clameter@sgi.com>
Cc: linux-mm@kvack.org, kamezawa.hiroyu@jp.fujitsu.com,
lee.schermerhorn@hp.com, hugh@veritas.com
Subject: Re: [PATCH 1/7] page migration: Reorder functions in migrate.c
Date: Fri, 28 Apr 2006 19:27:06 -0700 [thread overview]
Message-ID: <20060428192706.5bc76826.akpm@osdl.org> (raw)
In-Reply-To: <Pine.LNX.4.64.0604281744270.4378@schroedinger.engr.sgi.com>
Christoph Lameter <clameter@sgi.com> wrote:
>
> On Fri, 28 Apr 2006, Andrew Morton wrote:
>
> > hm. migrate_pages() locks two pages at the same time. We've avoided doing
> > that.
> >
> > a) what prevents ab/ba deadlocks in the migration code?
>
> Nothing right now.
>
OIC.
>
> > b) if some other part of the kernel later decides to lock two pages at
> > the same time, what protocol should that code follow to avoid ab/ba
> > deadlocks? lowest-pfn-first might be one.
>
> We could just do a TestSetPageLocked() on the newpage. If it fails then we
> postphone migration to the next loop.
>
> Patch on top of the one i just sent you or after the cleanup patches?
>
On top of page-migration-fix-fallback-behavior-for-dirty-pages.patch,
please. This is an unprivileged-user triggerable deadlock, no?
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next prev parent reply other threads:[~2006-04-29 2:27 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-04-28 6:03 Christoph Lameter
2006-04-28 6:03 ` [PATCH 2/7] page migration: Remove unnecessarily exported functions Christoph Lameter
2006-04-28 6:03 ` [PATCH 3/7] page migration: Change handling of address spaces Christoph Lameter
2006-04-28 6:03 ` [PATCH 4/7] page migration: Drop nr_refs parameter Christoph Lameter
2006-04-28 7:30 ` KAMEZAWA Hiroyuki
2006-04-28 13:57 ` Christoph Lameter
2006-04-28 6:03 ` [PATCH 5/7] page migration: synchronize from and to lists Christoph Lameter
2006-04-28 7:46 ` KAMEZAWA Hiroyuki
2006-04-28 15:31 ` Christoph Lameter
2006-04-29 0:27 ` KAMEZAWA Hiroyuki
2006-04-29 0:33 ` Christoph Lameter
2006-04-29 0:44 ` KAMEZAWA Hiroyuki
2006-04-29 0:46 ` Christoph Lameter
2006-04-28 6:03 ` [PATCH 6/7] page migration: Extract try_to_unmap Christoph Lameter
2006-04-28 6:03 ` [PATCH 7/7] page migration: Add new fallback function Christoph Lameter
2006-04-28 6:42 ` Christoph Lameter
2006-04-28 22:08 ` [PATCH 1/7] page migration: Reorder functions in migrate.c Andrew Morton
2006-04-28 23:01 ` Christoph Lameter
2006-04-28 23:18 ` Andrew Morton
2006-04-29 0:14 ` Christoph Lameter
2006-04-29 0:36 ` Andrew Morton
2006-04-29 0:46 ` Christoph Lameter
2006-04-29 2:27 ` Andrew Morton [this message]
2006-04-29 2:48 ` Christoph Lameter
2006-04-29 0:54 ` Christoph Lameter
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