From: Hugh Dickins <hugh@veritas.com>
To: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>,
Andrew Morton <akpm@linux-foundation.org>,
linux-mm <linux-mm@kvack.org>,
Balbir Singh <balbir@linux.vnet.ibm.com>,
Pavel Emelianov <xemul@openvz.org>, LiZefan <lizf@cn.fujitsu.com>
Subject: Re: [PATCH mmotm] memcg: avoid using buggy kmap at swap_cgroup
Date: Tue, 18 Nov 2008 16:56:57 +0000 (GMT) [thread overview]
Message-ID: <Pine.LNX.4.64.0811181653290.3506@blonde.site> (raw)
In-Reply-To: <Pine.LNX.4.64.0811181629070.417@blonde.site>
On Tue, 18 Nov 2008, Hugh Dickins wrote:
> On Wed, 19 Nov 2008, KAMEZAWA Hiroyuki wrote:
>
> > 2. later, add kmap_atomic + HighMem buffer support in explicit style.
> > maybe KM_BOUNCE_READ...can be used.....
>
> It's hardly appropriate (there's no bouncing here), and you could only
> use it if you disable interrupts. Oh, you do disable interrupts:
> why's that?
In fact, why do you even need the spinlock? I can see that you would
need it if in future you reduce the size of the elements of the array
from pointers; but at present, aren't you already in trouble if there's
a race on the pointer?
Hugh
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next prev parent reply other threads:[~2008-11-18 16:56 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-11-18 9:07 [PATCH mmotm] memcg: unmap KM_USER0 at shmem_map_and_free_swp if do_swap_account Daisuke Nishimura
2008-11-18 9:26 ` KAMEZAWA Hiroyuki
2008-11-18 10:21 ` Daisuke Nishimura
2008-11-18 12:08 ` Daisuke Nishimura
2008-11-18 12:48 ` Hugh Dickins
2008-11-18 15:17 ` Daisuke Nishimura
2008-11-18 16:12 ` [PATCH mmotm] memcg: avoid using buggy kmap at swap_cgroup KAMEZAWA Hiroyuki
2008-11-18 16:40 ` Hugh Dickins
2008-11-18 16:56 ` Hugh Dickins [this message]
2008-11-19 12:44 ` KAMEZAWA Hiroyuki
2008-11-21 5:54 ` [PATCH] memcg-swap-cgroup-for-remembering-usage-v2.patch KAMEZAWA Hiroyuki
2008-11-21 6:16 ` Daisuke Nishimura
2008-11-21 9:42 ` Daisuke Nishimura
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