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=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,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 785E1C433ED for ; Thu, 22 Apr 2021 11:16:06 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id D7B786145A for ; Thu, 22 Apr 2021 11:16:05 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D7B786145A Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=techsingularity.net Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 5C7E36B006C; Thu, 22 Apr 2021 07:16:05 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 59E636B0075; Thu, 22 Apr 2021 07:16:05 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 48FD86B0078; Thu, 22 Apr 2021 07:16:05 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0201.hostedemail.com [216.40.44.201]) by kanga.kvack.org (Postfix) with ESMTP id 2EA886B006C for ; Thu, 22 Apr 2021 07:16:05 -0400 (EDT) Received: from smtpin31.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id E44AE2464 for ; Thu, 22 Apr 2021 11:16:04 +0000 (UTC) X-FDA: 78059748648.31.CD44DF5 Received: from outbound-smtp63.blacknight.com (outbound-smtp63.blacknight.com [46.22.136.252]) by imf24.hostedemail.com (Postfix) with ESMTP id 8754CA0000FD for ; Thu, 22 Apr 2021 11:15:55 +0000 (UTC) Received: from mail.blacknight.com (pemlinmail03.blacknight.ie [81.17.254.16]) by outbound-smtp63.blacknight.com (Postfix) with ESMTPS id 470A0FAA5B for ; Thu, 22 Apr 2021 12:16:03 +0100 (IST) Received: (qmail 14733 invoked from network); 22 Apr 2021 11:16:03 -0000 Received: from unknown (HELO stampy.112glenside.lan) (mgorman@techsingularity.net@[84.203.17.248]) by 81.17.254.9 with ESMTPA; 22 Apr 2021 11:16:03 -0000 From: Mel Gorman To: Andrew Morton Cc: Chuck Lever , Jesper Dangaard Brouer , Thomas Gleixner , Peter Zijlstra , Ingo Molnar , Michal Hocko , Vlastimil Babka , Linux-MM , Linux-RT-Users , LKML , Mel Gorman Subject: [PATCH 7/9] mm/page_alloc: Explicitly acquire the zone lock in __free_pages_ok Date: Thu, 22 Apr 2021 12:14:39 +0100 Message-Id: <20210422111441.24318-8-mgorman@techsingularity.net> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20210422111441.24318-1-mgorman@techsingularity.net> References: <20210422111441.24318-1-mgorman@techsingularity.net> MIME-Version: 1.0 X-Rspamd-Queue-Id: 8754CA0000FD X-Stat-Signature: h9sixesfcpwju99sxw6ks4dgfq5q53ok X-Rspamd-Server: rspam02 Received-SPF: none (techsingularity.net>: No applicable sender policy available) receiver=imf24; identity=mailfrom; envelope-from=""; helo=outbound-smtp63.blacknight.com; client-ip=46.22.136.252 X-HE-DKIM-Result: none/none X-HE-Tag: 1619090155-149767 Content-Transfer-Encoding: quoted-printable 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: __free_pages_ok() disables IRQs before calling a common helper free_one_page() that acquires the zone lock. This is not safe according to Documentation/locking/locktypes.rst and in this context, IRQ disabling is not protecting a per_cpu_pages structure either or a local_lock would be used. This patch explicitly acquires the lock with spin_lock_irqsave instead of relying on a helper. This removes the last instance of local_irq_save() in page_alloc.c. Signed-off-by: Mel Gorman Acked-by: Vlastimil Babka --- mm/page_alloc.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 295624fe293b..c6e8da942905 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1547,21 +1547,21 @@ static void __free_pages_ok(struct page *page, un= signed int order, unsigned long flags; int migratetype; unsigned long pfn =3D page_to_pfn(page); + struct zone *zone =3D page_zone(page); =20 if (!free_pages_prepare(page, order, true)) return; =20 migratetype =3D get_pfnblock_migratetype(page, pfn); =20 - /* - * TODO FIX: Disable IRQs before acquiring IRQ-safe zone->lock - * and protect vmstat updates. - */ - local_irq_save(flags); + spin_lock_irqsave(&zone->lock, flags); __count_vm_events(PGFREE, 1 << order); - free_one_page(page_zone(page), page, pfn, order, migratetype, - fpi_flags); - local_irq_restore(flags); + if (unlikely(has_isolate_pageblock(zone) || + is_migrate_isolate(migratetype))) { + migratetype =3D get_pfnblock_migratetype(page, pfn); + } + __free_one_page(page, pfn, zone, order, migratetype, fpi_flags); + spin_unlock_irqrestore(&zone->lock, flags); } =20 void __free_pages_core(struct page *page, unsigned int order) --=20 2.26.2