From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx124.postini.com [74.125.245.124]) by kanga.kvack.org (Postfix) with SMTP id 7271D6B004A for ; Wed, 15 Feb 2012 21:05:35 -0500 (EST) Received: from m1.gw.fujitsu.co.jp (unknown [10.0.50.71]) by fgwmail5.fujitsu.co.jp (Postfix) with ESMTP id D9EF73EE0C2 for ; Thu, 16 Feb 2012 11:05:33 +0900 (JST) Received: from smail (m1 [127.0.0.1]) by outgoing.m1.gw.fujitsu.co.jp (Postfix) with ESMTP id C32E745DE59 for ; Thu, 16 Feb 2012 11:05:33 +0900 (JST) Received: from s1.gw.fujitsu.co.jp (s1.gw.fujitsu.co.jp [10.0.50.91]) by m1.gw.fujitsu.co.jp (Postfix) with ESMTP id AC89645DE56 for ; Thu, 16 Feb 2012 11:05:33 +0900 (JST) Received: from s1.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s1.gw.fujitsu.co.jp (Postfix) with ESMTP id A13E21DB804E for ; Thu, 16 Feb 2012 11:05:33 +0900 (JST) Received: from ml14.s.css.fujitsu.com (ml14.s.css.fujitsu.com [10.240.81.134]) by s1.gw.fujitsu.co.jp (Postfix) with ESMTP id 5CB271DB803F for ; Thu, 16 Feb 2012 11:05:33 +0900 (JST) Date: Thu, 16 Feb 2012 11:04:08 +0900 From: KAMEZAWA Hiroyuki Subject: Re: [PATCH RFC 00/15] mm: memory book keeping and lru_lock splitting Message-Id: <20120216110408.f35c3448.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: <20120215224221.22050.80605.stgit@zurg> References: <20120215224221.22050.80605.stgit@zurg> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Konstantin Khlebnikov Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Hugh Dickins , "hannes@cmpxchg.org" On Thu, 16 Feb 2012 02:57:04 +0400 Konstantin Khlebnikov wrote: > There should be no logic changes in this patchset, this is only tossing bits around. > [ This patchset is on top some memcg cleanup/rework patches, > which I sent to linux-mm@ today/yesterday ] > > Most of things in this patchset are self-descriptive, so here brief plan: > AFAIK, Hugh Dickins said he has per-zone-per-lru-lock and is testing it. So, please CC him and Johannes, at least. > * Transmute struct lruvec into struct book. Like real book this struct will > store set of pages for one zone. It will be working unit for reclaimer code. > [ If memcg is disabled in config there will only one book embedded into struct zone ] > Why you need to add new structure rahter than enhancing lruvec ? "book" means a binder of pages ? > * move page-lru counters to struct book > [ this adds extra overhead in add_page_to_lru_list()/del_page_from_lru_list() for > non-memcg case, but I believe it will be invisible, only one non-atomic add/sub > in the same cacheline with lru list ] > This seems straightforward. > * unify inactive_list_is_low_global() and cleanup reclaimer code > * replace struct mem_cgroup_zone with single pointer to struct book Hm, ok. > * optimize page to book translations, move it upper in the call stack, > replace some struct zone arguments with struct book pointer. > a page->book transrater from patch 2/15 +struct book *page_book(struct page *page) +{ + struct mem_cgroup_per_zone *mz; + struct page_cgroup *pc; + + if (mem_cgroup_disabled()) + return &page_zone(page)->book; + + pc = lookup_page_cgroup(page); + if (!PageCgroupUsed(pc)) + return &page_zone(page)->book; + /* Ensure pc->mem_cgroup is visible after reading PCG_USED. */ + smp_rmb(); + mz = mem_cgroup_zoneinfo(pc->mem_cgroup, + page_to_nid(page), page_zonenum(page)); + return &mz->book; +} What happens when pc->mem_cgroup is rewritten by move_account() ? Where is the guard for lockless access of this ? Thanks, -Kame -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org