From: Christoph Lameter <clameter@sgi.com>
To: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: hugh@veritas.com, linux-kernel@vger.kernel.org,
linux-mm@kvack.org, akpm@osdl.org
Subject: Re: Read/Write migration entries: Implement correct behavior in copy_one_pte
Date: Tue, 18 Apr 2006 18:27:28 -0700 (PDT) [thread overview]
Message-ID: <Pine.LNX.4.64.0604181823590.9747@schroedinger.engr.sgi.com> (raw)
In-Reply-To: <20060419095044.d7333b21.kamezawa.hiroyu@jp.fujitsu.com>
On Wed, 19 Apr 2006, KAMEZAWA Hiroyuki wrote:
> > Note that this is again only a partial solution. mprotect() also has the
> > potential of changing the write status to read.
> yes. in change_pte_range().
>
> Note:
> fork() and mprotect() both requires mm->mmap_sem.
> So both of them is not problem when migration holds mm->mmap_sem.
> If we does lazy migration or memory hot removing or allows migration from
> another process, this will be problem.
Oh. We already allow migration from another process since the page may
be mapped by multiple mm's. Page migration will then replace the ptes in
*all* mm_structs that map this page with migration entries.
So we need a fix here.
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next prev parent reply other threads:[~2006-04-19 1:27 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-04-18 18:21 Read/Write migration entries: Implement correct behavior in copy_one_pte Christoph Lameter
2006-04-19 0:50 ` KAMEZAWA Hiroyuki
2006-04-19 1:27 ` Christoph Lameter [this message]
2006-04-19 3:39 ` KAMEZAWA Hiroyuki
2006-04-20 20:17 ` Christoph Lameter
2006-04-20 20:18 ` Read/Write migration entries: Make mprotect() convert write migration entries to read Christoph Lameter
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