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From: Hugh Dickins <hughd@google.com>
To: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Konstantin Khlebnikov <khlebnikov@openvz.org>,
	Johannes Weiner <hannes@cmpxchg.org>,
	Ying Han <yinghan@google.com>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 5/10] mm/memcg: introduce page_relock_lruvec
Date: Tue, 21 Feb 2012 14:36:56 -0800 (PST)	[thread overview]
Message-ID: <alpine.LSU.2.00.1202211426010.2012@eggly.anvils> (raw)
In-Reply-To: <20120221173859.f57d00f5.kamezawa.hiroyu@jp.fujitsu.com>

On Tue, 21 Feb 2012, KAMEZAWA Hiroyuki wrote:
> 
> No perforamce impact by replacing spin_lock_irq()/spin_unlock_irq() to
> spin_lock_irqsave() and spin_unlock_irqrestore() ?

None that I noticed - but that is not at all a reassuring answer!

It worries me a little.  I think it would make more or less difference
on different architectures, and I forget where x86 stands there - one
of the more or the less affected?  Worth branches down inside
page_relock_lruvec()?

It's also unfortunate to be "losing" the information of where _irq
is needed and where _irqsave (but not much gets lost with git).

It's something that can be fixed - and I think Konstantin's version
already keeps the variants: I just didn't want to get confused by them,
while focussing on the locking details.

Hugh

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  reply	other threads:[~2012-02-21 22:37 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-02-20 23:26 [PATCH 0/10] mm/memcg: per-memcg per-zone lru locking Hugh Dickins
2012-02-20 23:28 ` [PATCH 1/10] mm/memcg: scanning_global_lru means mem_cgroup_disabled Hugh Dickins
2012-02-21  8:03   ` KAMEZAWA Hiroyuki
2012-02-20 23:29 ` [PATCH 2/10] mm/memcg: move reclaim_stat into lruvec Hugh Dickins
2012-02-21  8:05   ` KAMEZAWA Hiroyuki
2012-02-20 23:30 ` [PATCH 3/10] mm/memcg: add zone pointer " Hugh Dickins
2012-02-21  8:08   ` KAMEZAWA Hiroyuki
2012-02-20 23:32 ` [PATCH 4/10] mm/memcg: apply add/del_page to lruvec Hugh Dickins
2012-02-21  8:20   ` KAMEZAWA Hiroyuki
2012-02-21 22:25     ` Hugh Dickins
2012-02-20 23:33 ` [PATCH 5/10] mm/memcg: introduce page_relock_lruvec Hugh Dickins
2012-02-21  8:38   ` KAMEZAWA Hiroyuki
2012-02-21 22:36     ` Hugh Dickins [this message]
2012-02-20 23:34 ` [PATCH 6/10] mm/memcg: take care over pc->mem_cgroup Hugh Dickins
2012-02-21  5:55   ` Konstantin Khlebnikov
2012-02-21 19:37     ` Hugh Dickins
2012-02-21 20:40       ` Konstantin Khlebnikov
2012-02-21 22:05         ` Hugh Dickins
2012-02-21  6:05   ` Konstantin Khlebnikov
2012-02-21 20:00     ` Hugh Dickins
2012-02-21  9:13   ` KAMEZAWA Hiroyuki
2012-02-21 23:03     ` Hugh Dickins
2012-02-22  4:05       ` Konstantin Khlebnikov
2012-02-20 23:35 ` [PATCH 7/10] mm/memcg: remove mem_cgroup_reset_owner Hugh Dickins
2012-02-21  9:17   ` KAMEZAWA Hiroyuki
2012-02-20 23:36 ` [PATCH 8/10] mm/memcg: nest lru_lock inside page_cgroup lock Hugh Dickins
2012-02-21  9:48   ` KAMEZAWA Hiroyuki
2012-02-20 23:38 ` [PATCH 9/10] mm/memcg: move lru_lock into lruvec Hugh Dickins
2012-02-21  7:08   ` Konstantin Khlebnikov
2012-02-21 20:12     ` Hugh Dickins
2012-02-21 21:35       ` Konstantin Khlebnikov
2012-02-21 22:12         ` Hugh Dickins
2012-02-22  3:43           ` Konstantin Khlebnikov
2012-02-22  6:09             ` Hugh Dickins
2012-02-23 14:21               ` Konstantin Khlebnikov
2012-02-20 23:39 ` [PATCH 10/10] mm/memcg: per-memcg per-zone lru locking Hugh Dickins

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