Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759713Ab3HNJPu (ORCPT ); Wed, 14 Aug 2013 05:15:50 -0400 Received: from szxga01-in.huawei.com ([119.145.14.64]:63325 "EHLO szxga01-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752162Ab3HNJPs (ORCPT ); Wed, 14 Aug 2013 05:15:48 -0400 Message-ID: <520B4A76.8050903@huawei.com> Date: Wed, 14 Aug 2013 17:14:30 +0800 From: Xishi Qiu User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:12.0) Gecko/20120428 Thunderbird/12.0.1 MIME-Version: 1.0 To: Mel Gorman CC: Andrew Morton , , Minchan Kim , , , LKML Subject: Re: [PATCH] mm: skip the page buddy block instead of one page References: <520B0B75.4030708@huawei.com> <20130814085711.GK2296@suse.de> In-Reply-To: <20130814085711.GK2296@suse.de> Content-Type: text/plain; charset="ISO-8859-15" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.135.74.196] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 933 Lines: 25 On 2013/8/14 16:57, Mel Gorman wrote: > On Wed, Aug 14, 2013 at 12:45:41PM +0800, Xishi Qiu wrote: >> A large free page buddy block will continue many times, so if the page >> is free, skip the whole page buddy block instead of one page. >> >> Signed-off-by: Xishi Qiu > > page_order cannot be used unless zone->lock is held which is not held in > this path. Acquiring the lock would prevent parallel allocations from the > buddy allocator (per-cpu allocator would be ok except for refills). I expect > it would not be a good tradeoff to acquire the lock just to use page_order. > > Nak. > Oh, you are right, we must hold zone->lock first. Thanks, Xishi Qiu -- 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/