From mboxrd@z Thu Jan 1 00:00:00 1970 Subject: Re: [RFC][PATCH] memory controller per zone patches take 2 [4/10] calculate mapped ratio for memory cgroup In-Reply-To: Your message of "Thu, 22 Nov 2007 17:40:15 +0900" <20071122174015.c5ef61ae.kamezawa.hiroyu@jp.fujitsu.com> References: <20071122174015.c5ef61ae.kamezawa.hiroyu@jp.fujitsu.com> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Message-Id: <20071122084647.485981CEE98@siro.lan> Date: Thu, 22 Nov 2007 17:46:47 +0900 (JST) From: yamamoto@valinux.co.jp (YAMAMOTO Takashi) Sender: owner-linux-mm@kvack.org Return-Path: To: kamezawa.hiroyu@jp.fujitsu.com Cc: balbir@linux.vnet.ibm.com, containers@lists.osdl.org, linux-mm@kvack.org List-ID: > On Thu, 22 Nov 2007 17:34:20 +0900 (JST) > yamamoto@valinux.co.jp (YAMAMOTO Takashi) wrote: > > > > > > + /* usage is recorded in bytes */ > > > > > + total = mem->res.usage >> PAGE_SHIFT; > > > > > + rss = mem_cgroup_read_stat(&mem->stat, MEM_CGROUP_STAT_RSS); > > > > > + return (rss * 100) / total; > > > > > > > > Never tried 64 bit division on a 32 bit system. I hope we don't > > > > have to resort to do_div() sort of functionality. > > > > > > > Hmm, maybe it's better to make these numebrs be just "long". > > > I'll try to change per-cpu-counter implementation. > > > > > > Thanks, > > > -Kame > > > > besides that, i think 'total' can be zero here. > > > Ah, This is what I do now. > == > +/* > + * Calculate mapped_ratio under memory controller. This will be used in > + * vmscan.c for deteremining we have to reclaim mapped pages. > + */ > +int mem_cgroup_calc_mapped_ratio(struct mem_cgroup *mem) > +{ > + long total, rss; > + > + /* > + * usage is recorded in bytes. But, here, we assume the number of > + * physical pages can be represented by "long" on any arch. > + */ > + total = (long) (mem->res.usage >> PAGE_SHIFT); > + rss = (long)mem_cgroup_read_stat(&mem->stat, MEM_CGROUP_STAT_RSS); > + return (int)((rss * 100L) / total); > +} > == > > maybe works well. > > -Kame i meant that "/ total" can cause a division-by-zero exception. YAMAMOTO Takashi -- 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/ . Don't email: email@kvack.org