From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S939611AbdEXKm6 (ORCPT ); Wed, 24 May 2017 06:42:58 -0400 Received: from mx2.suse.de ([195.135.220.15]:58221 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1761437AbdEXKm4 (ORCPT ); Wed, 24 May 2017 06:42:56 -0400 Subject: Re: [Question] Mlocked count will not be decreased To: Yisheng Xie , Kefeng Wang , linux-mm@kvack.org, linux-kernel@vger.kernel.org, zhongjiang , Qiuxishi References: <85591559-2a99-f46b-7a5a-bc7affb53285@huawei.com> <93f1b063-6288-d109-117d-d3c1cf152a8e@suse.cz> From: Vlastimil Babka Message-ID: <53778229-34ed-56a2-7f94-c8cd2f519de6@suse.cz> Date: Wed, 24 May 2017 12:42:21 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.8.0 MIME-Version: 1.0 In-Reply-To: <93f1b063-6288-d109-117d-d3c1cf152a8e@suse.cz> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 05/24/2017 12:32 PM, Vlastimil Babka wrote: > > Weird, I can reproduce the issue on my desktop's 4.11 distro kernel, but > not in qemu and small kernel build, for some reason. So I couldn't test Ah, Tetsuo's more aggressive testcase worked and I can confirm the fix. However this would be slightly better, as it doesn't do the increment in fastpath: diff --git a/mm/mlock.c b/mm/mlock.c index 0dd9ca18e19e..721679a2c1aa 100644 --- a/mm/mlock.c +++ b/mm/mlock.c @@ -286,7 +286,7 @@ static void __munlock_pagevec(struct pagevec *pvec, struct zone *zone) { int i; int nr = pagevec_count(pvec); - int delta_munlocked; + int delta_munlocked = -nr; struct pagevec pvec_putback; int pgrescued = 0; @@ -306,6 +306,8 @@ static void __munlock_pagevec(struct pagevec *pvec, struct zone *zone) continue; else __munlock_isolation_failed(page); + } else { + delta_munlocked++; } /* @@ -317,7 +319,6 @@ static void __munlock_pagevec(struct pagevec *pvec, struct zone *zone) pagevec_add(&pvec_putback, pvec->pages[i]); pvec->pages[i] = NULL; } - delta_munlocked = -nr + pagevec_count(&pvec_putback); __mod_zone_page_state(zone, NR_MLOCK, delta_munlocked); spin_unlock_irq(zone_lru_lock(zone));