From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail172.messagelabs.com (mail172.messagelabs.com [216.82.254.3]) by kanga.kvack.org (Postfix) with ESMTP id 267DD5F0040 for ; Tue, 19 Oct 2010 21:09:43 -0400 (EDT) Date: Wed, 20 Oct 2010 09:50:56 +0900 From: Daisuke Nishimura Subject: Re: [PATCH v3 07/11] memcg: add dirty limits to mem_cgroup Message-Id: <20101020095056.48098b34.nishimura@mxp.nes.nec.co.jp> In-Reply-To: <1287448784-25684-8-git-send-email-gthelen@google.com> References: <1287448784-25684-1-git-send-email-gthelen@google.com> <1287448784-25684-8-git-send-email-gthelen@google.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: Greg Thelen Cc: Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org, containers@lists.osdl.org, Andrea Righi , Balbir Singh , KAMEZAWA Hiroyuki , Minchan Kim , Ciju Rajan K , David Rientjes , Daisuke Nishimura List-ID: > +static unsigned long long > +memcg_hierarchical_free_pages(struct mem_cgroup *mem) > +{ > + struct cgroup *cgroup; > + unsigned long long min_free, free; > + > + min_free = res_counter_read_u64(&mem->res, RES_LIMIT) - > + res_counter_read_u64(&mem->res, RES_USAGE); > + cgroup = mem->css.cgroup; > + if (!mem->use_hierarchy) > + goto out; > + > + while (cgroup->parent) { > + cgroup = cgroup->parent; > + mem = mem_cgroup_from_cont(cgroup); > + if (!mem->use_hierarchy) > + break; > + free = res_counter_read_u64(&mem->res, RES_LIMIT) - > + res_counter_read_u64(&mem->res, RES_USAGE); > + min_free = min(min_free, free); > + } > +out: > + /* Translate free memory in pages */ > + return min_free >> PAGE_SHIFT; > +} > + I think you can simplify this function using parent_mem_cgroup(). unsigned long free, min_free = ULLONG_MAX; while (mem) { free = res_counter_read_u64(&mem->res, RES_LIMIT) - res_counter_read_u64(&mem->res, RES_USAGE); min_free = min(min_free, free); mem = parent_mem_cgroup(); } /* Translate free memory in pages */ return min_free >> PAGE_SHIFT; And, IMHO, we should return min(global_page_state(NR_FREE_PAGES), min_free >> PAGE_SHIFT). Because we are allowed to set no-limit(or a very big limit) in memcg, so min_free can be very big if we don't set a limit against all the memcg's in hierarchy. Thanks, Dasiuke Nishimura. -- 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