From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, UNPARSEABLE_RELAY,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7D398C3F2D7 for ; Tue, 3 Mar 2020 16:16:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4FA892073D for ; Tue, 3 Mar 2020 16:16:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730325AbgCCQQn (ORCPT ); Tue, 3 Mar 2020 11:16:43 -0500 Received: from out30-133.freemail.mail.aliyun.com ([115.124.30.133]:37245 "EHLO out30-133.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729208AbgCCQQn (ORCPT ); Tue, 3 Mar 2020 11:16:43 -0500 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R181e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01f04452;MF=shile.zhang@linux.alibaba.com;NM=1;PH=DS;RN=6;SR=0;TI=SMTPD_---0TrZg1ZS_1583252154; Received: from e18g09479.et15sqa.tbsite.net(mailfrom:shile.zhang@linux.alibaba.com fp:SMTPD_---0TrZg1ZS_1583252154) by smtp.aliyun-inc.com(127.0.0.1); Wed, 04 Mar 2020 00:16:24 +0800 From: Shile Zhang To: Andrew Morton , Kirill Tkhai , Pavel Tatashin Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Shile Zhang Subject: [PATCH v2 1/1] mm: fix interrupt disabled long time inside deferred_init_memmap() Date: Wed, 4 Mar 2020 00:15:51 +0800 Message-Id: <20200303161551.132263-2-shile.zhang@linux.alibaba.com> X-Mailer: git-send-email 2.24.0.rc2 In-Reply-To: <20200303161551.132263-1-shile.zhang@linux.alibaba.com> References: <20200303161551.132263-1-shile.zhang@linux.alibaba.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When 'CONFIG_DEFERRED_STRUCT_PAGE_INIT' is set, 'pgdatinit' kthread will initialise the deferred pages with local interrupts disabled. It is introduced by commit 3a2d7fa8a3d5 ("mm: disable interrupts while initializing deferred pages"). The local interrupt will be disabled long time inside deferred_init_memmap(), depends on memory size. On machine with NCPUS <= 2, the 'pgdatinit' kthread could be pined on boot CPU, then the tick timer will stuck long time, which caused the system wall time inaccuracy. For example, the dmesg shown that: [ 0.197975] node 0 initialised, 32170688 pages in 1ms Obviously, 1ms is unreasonable. Now, fix it by restore in the pending interrupts inside the while loop. The reasonable demsg shown likes: [ 1.069306] node 0 initialised, 32203456 pages in 894ms Signed-off-by: Shile Zhang --- mm/page_alloc.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 3c4eb750a199..d3f337f2e089 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1809,8 +1809,12 @@ static int __init deferred_init_memmap(void *data) * that we can avoid introducing any issues with the buddy * allocator. */ - while (spfn < epfn) + while (spfn < epfn) { nr_pages += deferred_init_maxorder(&i, zone, &spfn, &epfn); + /* let in any pending interrupts */ + local_irq_restore(flags); + local_irq_save(flags); + } zone_empty: pgdat_resize_unlock(pgdat, &flags); -- 2.24.0.rc2