From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S939391AbdAFD1t (ORCPT ); Thu, 5 Jan 2017 22:27:49 -0500 Received: from out0-141.mail.aliyun.com ([140.205.0.141]:35171 "EHLO out0-141.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754330AbdAFD1f (ORCPT ); Thu, 5 Jan 2017 22:27:35 -0500 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R101e4;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e02c03291;MF=hillf.zj@alibaba-inc.com;NM=1;PH=DS;RN=4;SR=0;TI=SMTPD_---.7OinYj0_1483673206; Reply-To: "Hillf Danton" From: "Hillf Danton" To: "'Mel Gorman'" , "'Jesper Dangaard Brouer'" Cc: "'Linux Kernel'" , "'Linux-MM'" References: <20170104111049.15501-1-mgorman@techsingularity.net> <20170104111049.15501-4-mgorman@techsingularity.net> In-Reply-To: <20170104111049.15501-4-mgorman@techsingularity.net> Subject: Re: [PATCH 3/4] mm, page_allocator: Only use per-cpu allocator for irq-safe requests Date: Fri, 06 Jan 2017 11:26:46 +0800 Message-ID: <00ee01d267cc$b61feaa0$225fbfe0$@alibaba-inc.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit X-Mailer: Microsoft Outlook 14.0 Thread-Index: AQDSEFujIimX2KX/REGb7JUBMTEPagK0FPKsoxXRzOA= Content-Language: zh-cn Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wednesday, January 04, 2017 7:11 PM Mel Gorman wrote: > @@ -2647,9 +2644,8 @@ static struct page *rmqueue_pcplist(struct zone *preferred_zone, > struct list_head *list; > bool cold = ((gfp_flags & __GFP_COLD) != 0); > struct page *page; > - unsigned long flags; > > - local_irq_save(flags); > + preempt_disable(); > pcp = &this_cpu_ptr(zone->pageset)->pcp; > list = &pcp->lists[migratetype]; > page = __rmqueue_pcplist(zone, order, gfp_flags, migratetype, > @@ -2658,7 +2654,7 @@ static struct page *rmqueue_pcplist(struct zone *preferred_zone, > __count_zid_vm_events(PGALLOC, page_zonenum(page), 1 << order); > zone_statistics(preferred_zone, zone, gfp_flags); > } > - local_irq_restore(flags); > + preempt_enable(); > return page; > } > With PREEMPT configured, preempt_enable() adds entry point to schedule(). Is that needed when we try to allocate a page? Hillf