Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752047Ab2JQWL6 (ORCPT ); Wed, 17 Oct 2012 18:11:58 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:57038 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751736Ab2JQWL4 (ORCPT ); Wed, 17 Oct 2012 18:11:56 -0400 Date: Wed, 17 Oct 2012 15:11:55 -0700 From: Andrew Morton To: Glauber Costa Cc: , , Mel Gorman , Tejun Heo , Michal Hocko , Johannes Weiner , , Christoph Lameter , David Rientjes , Pekka Enberg , , , Suleiman Souhlal Subject: Re: [PATCH v5 01/14] memcg: Make it possible to use the stock for more than one page. Message-Id: <20121017151155.d417bd13.akpm@linux-foundation.org> In-Reply-To: <1350382611-20579-2-git-send-email-glommer@parallels.com> References: <1350382611-20579-1-git-send-email-glommer@parallels.com> <1350382611-20579-2-git-send-email-glommer@parallels.com> X-Mailer: Sylpheed 3.0.2 (GTK+ 2.20.1; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1790 Lines: 49 On Tue, 16 Oct 2012 14:16:38 +0400 Glauber Costa wrote: > From: Suleiman Souhlal > > We currently have a percpu stock cache scheme that charges one page at a > time from memcg->res, the user counter. When the kernel memory > controller comes into play, we'll need to charge more than that. > > This is because kernel memory allocations will also draw from the user > counter, and can be bigger than a single page, as it is the case with > the stack (usually 2 pages) or some higher order slabs. > > ... > > -/* > - * Try to consume stocked charge on this cpu. If success, one page is consumed > - * from local stock and true is returned. If the stock is 0 or charges from a > - * cgroup which is not current target, returns false. This stock will be > - * refilled. > +/** > + * consume_stock: Try to consume stocked charge on this cpu. > + * @memcg: memcg to consume from. > + * @nr_pages: how many pages to charge. > + * > + * The charges will only happen if @memcg matches the current cpu's memcg > + * stock, and at least @nr_pages are available in that stock. Failure to > + * service an allocation will refill the stock. > + * > + * returns true if succesfull, false otherwise. spello. > */ > -static bool consume_stock(struct mem_cgroup *memcg) > +static bool consume_stock(struct mem_cgroup *memcg, int nr_pages) I don't believe there is a case for nr_pages < 0 here? If not then I suggest that it would be clearer to use an unsigned type, like memcg_stock_pcp.stock. > > ... > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/