From patchwork Tue Sep 22 13:56:50 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Oscar Salvador X-Patchwork-Id: 11792631 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 2E046112E for ; Tue, 22 Sep 2020 13:57:46 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id EB32220719 for ; Tue, 22 Sep 2020 13:57:45 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EB32220719 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id A2C956B00C5; Tue, 22 Sep 2020 09:57:14 -0400 (EDT) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id 9B52A6B00C7; Tue, 22 Sep 2020 09:57:14 -0400 (EDT) X-Original-To: int-list-linux-mm@kvack.org X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 8A1376B00C8; Tue, 22 Sep 2020 09:57:14 -0400 (EDT) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0026.hostedemail.com [216.40.44.26]) by kanga.kvack.org (Postfix) with ESMTP id 6DF7E6B00C5 for ; Tue, 22 Sep 2020 09:57:14 -0400 (EDT) Received: from smtpin27.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 336733629 for ; Tue, 22 Sep 2020 13:57:14 +0000 (UTC) X-FDA: 77290849188.27.point22_5f171032714e Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin27.hostedemail.com (Postfix) with ESMTP id 09BFD3D663 for ; Tue, 22 Sep 2020 13:57:14 +0000 (UTC) X-Spam-Summary: 1,0,0,,d41d8cd98f00b204,osalvador@suse.de,,RULES_HIT:30054,0,RBL:195.135.220.15:@suse.de:.lbl8.mailshell.net-64.100.201.201 62.2.6.2;04ygzixsoor4zs9fet6wfwg7sjetjyc7n47jk6jx3w6n55umzgj654mizrgbdg4.wyoax19apzybncqj1rdkfammkqa4sb8jxyzdfwzeofwa1wnkzr19grxbba6qc8n.1-lbl8.mailshell.net-223.238.255.100,CacheIP:none,Bayesian:0.5,0.5,0.5,Netcheck:none,DomainCache:0,MSF:not bulk,SPF:fp,MSBL:0,DNSBL:neutral,Custom_rules:0:0:0,LFtime:25,LUA_SUMMARY:none X-HE-Tag: point22_5f171032714e X-Filterd-Recvd-Size: 2497 Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) by imf09.hostedemail.com (Postfix) with ESMTP for ; Tue, 22 Sep 2020 13:57:13 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 39B4BAFBC; Tue, 22 Sep 2020 13:57:49 +0000 (UTC) From: Oscar Salvador To: akpm@linux-foundation.org Cc: aris@ruivo.org, naoya.horiguchi@nec.com, mhocko@kernel.org, tony.luck@intel.com, cai@lca.pw, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Oscar Salvador Subject: [PATCH v7 14/14] mm,hwpoison: Try to narrow window race for free pages Date: Tue, 22 Sep 2020 15:56:50 +0200 Message-Id: <20200922135650.1634-15-osalvador@suse.de> X-Mailer: git-send-email 2.13.7 In-Reply-To: <20200922135650.1634-1-osalvador@suse.de> References: <20200922135650.1634-1-osalvador@suse.de> X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Aristeu Rozanski reported that a customer test case started to report -EBUSY after the hwpoison rework patchset. There is a race window between spotting a free page and taking it off its buddy freelist, so it might be that by the time we try to take it off, the page has been already allocated. This patch tries to handle such race window by trying to handle the new type of page again if the page was allocated under us. Signed-off-by: Oscar Salvador Reported-by: Aristeu Rozanski Tested-by: Aristeu Rozanski Acked-by: Naoya Horiguchi --- mm/memory-failure.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/mm/memory-failure.c b/mm/memory-failure.c index 46b1821d2817..8f23d3c7a0a2 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -1903,6 +1903,7 @@ int soft_offline_page(unsigned long pfn, int flags) { int ret; struct page *page; + bool try_again = true; if (!pfn_valid(pfn)) return -ENXIO; @@ -1918,6 +1919,7 @@ int soft_offline_page(unsigned long pfn, int flags) return 0; } +retry: get_online_mems(); ret = get_any_page(page, pfn, flags); put_online_mems(); @@ -1925,7 +1927,10 @@ int soft_offline_page(unsigned long pfn, int flags) if (ret > 0) ret = soft_offline_in_use_page(page); else if (ret == 0) - ret = soft_offline_free_page(page); + if (soft_offline_free_page(page) && try_again) { + try_again = false; + goto retry; + } return ret; }