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Date: Thu, 7 Oct 2010 10:54:56 +0900 From: Daisuke Nishimura <nishimura@....nes.nec.co.jp> To: KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com> Cc: Minchan Kim <minchan.kim@...il.com>, Greg Thelen <gthelen@...gle.com>, Andrew Morton <akpm@...ux-foundation.org>, linux-kernel@...r.kernel.org, linux-mm@...ck.org, containers@...ts.osdl.org, Andrea Righi <arighi@...eler.com>, Balbir Singh <balbir@...ux.vnet.ibm.com>, Daisuke Nishimura <nishimura@....nes.nec.co.jp> Subject: Re: [PATCH 04/10] memcg: disable local interrupts in lock_page_cgroup() On Thu, 7 Oct 2010 09:35:45 +0900 KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com> wrote: > On Wed, 6 Oct 2010 09:15:34 +0900 > Minchan Kim <minchan.kim@...il.com> wrote: > > > First of all, we could add your patch as it is and I don't expect any > > regression report about interrupt latency. > > That's because many embedded guys doesn't use mmotm and have a > > tendency to not report regression of VM. > > Even they don't use memcg. Hmm... > > > > I pass the decision to MAINTAINER Kame and Balbir. > > Thanks for the detail explanation. > > > > Hmm. IRQ delay is a concern. So, my option is this. How do you think ? > > 1. remove local_irq_save()/restore() in lock/unlock_page_cgroup(). > yes, I don't like it. > > 2. At moving charge, do this: > a) lock_page()/ or trylock_page() > b) wait_on_page_writeback() > c) do move_account under lock_page_cgroup(). > c) unlock_page() > > > Then, Writeback updates will never come from IRQ context while > lock/unlock_page_cgroup() is held by move_account(). There will be no race. > hmm, if we'll do that, I think we need to do that under pte_lock in mem_cgroup_move_charge_pte_range(). But, we can't do wait_on_page_writeback() under pte_lock, right? Or, we need re-organize current move-charge implementation. Thanks, Daisuke Nishimura. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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