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=-9.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, 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 6C3E5C33CB7 for ; Mon, 20 Jan 2020 03:43:04 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 142D820684 for ; Mon, 20 Jan 2020 03:43:03 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=lca.pw header.i=@lca.pw header.b="H7wsE3DH" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 142D820684 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lca.pw Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 71CB66B05A4; Sun, 19 Jan 2020 22:43:03 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 6CDC46B05A5; Sun, 19 Jan 2020 22:43:03 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 5E4B16B05A6; Sun, 19 Jan 2020 22:43:03 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0203.hostedemail.com [216.40.44.203]) by kanga.kvack.org (Postfix) with ESMTP id 4651E6B05A4 for ; Sun, 19 Jan 2020 22:43:03 -0500 (EST) Received: from smtpin13.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with SMTP id F0359181AC9BF for ; Mon, 20 Jan 2020 03:43:02 +0000 (UTC) X-FDA: 76396616604.13.news56_71e272920524c X-HE-Tag: news56_71e272920524c X-Filterd-Recvd-Size: 6385 Received: from mail-qt1-f171.google.com (mail-qt1-f171.google.com [209.85.160.171]) by imf37.hostedemail.com (Postfix) with ESMTP for ; Mon, 20 Jan 2020 03:43:02 +0000 (UTC) Received: by mail-qt1-f171.google.com with SMTP id w47so26653552qtk.4 for ; Sun, 19 Jan 2020 19:43:02 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=lca.pw; s=google; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=XE7pI/1UkwxiaUIIDslwmE8c/uvsS/a7QnJibWPUjk8=; b=H7wsE3DH2UAfgH9BPwA6nHJQWjTlb8LNVMxYkbYMAnsC8wbtsl3pZeHoW35dNX+9bi 33wubpQLVkJKWHCbLz/bFfSDh3orrINpBFczmFEm11SFvr/afJyQ8bicdsMeoiGru4RE iYWx4dAnHJVeI+ms6wvaAKw6D6k1o5l5Q5WEERKtdd/RPXV3JjY/v3QO4d18ucbtrvWF J9LymZQzsTTpp/USsaeq2wkSs2daXQ9UseSP4q17wvqwVulOK6VTDWzfDYI8oqm7byDj EA63IysBWbb1PtvN+Ude5aBPW6qR0qrVNvdJm3Mli5NzYRoMHapR4Pz1QjtpO7cuvOGR 4hEQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=XE7pI/1UkwxiaUIIDslwmE8c/uvsS/a7QnJibWPUjk8=; b=b71VGY3IQPuxb9TneNEmeKWHeX8ilMfGxIWPIIRYqhv1k6iNnmFrwVUQqHQgsdJbk2 66rjrKYFpjOZqjqEoHGZOt6lnqxihyVOIoZeiZJj2cALfwMG74r3KCsEk8l7G2FgsWuz j1WEjB77pyu2oF/fZQ35a9R14MVnivSJsvJoB6brJJaPw4PPbqikr2+E+C/UZbkeiNiD xf7rPSlLaI2UtegG38GT9wWQ8pWYtOak5uX8CCVHg5/Qnpisu+lhgBmuwTEre7gcsURM 7Dk1IVm6C1QgyAdOT2uiiFxodpsfXpJGx9tH9YQI8Ai64qHS0RnYbP1qZ74c7jjF89gE tcsA== X-Gm-Message-State: APjAAAUilXK5VlgTJ1AonQ/rMlP+C7ZrQG8ngrXf7GDqU5NxaL+CLn4F fgqrh33xjM1KQ4WOs7mLwqSKRA== X-Google-Smtp-Source: APXvYqyQZ+NKIh4NSv9lo3s1cdPpbMu7ss6hh5VkYE+4i2Iklpcr0kYCTinu2TAYv431zJaOjuJazg== X-Received: by 2002:ac8:6f63:: with SMTP id u3mr18756005qtv.39.1579491781901; Sun, 19 Jan 2020 19:43:01 -0800 (PST) Received: from ovpn-121-56.rdu2.redhat.com (pool-71-184-117-43.bstnma.fios.verizon.net. [71.184.117.43]) by smtp.gmail.com with ESMTPSA id h32sm17240718qth.2.2020.01.19.19.43.00 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sun, 19 Jan 2020 19:43:01 -0800 (PST) From: Qian Cai To: akpm@linux-foundation.org Cc: mhocko@kernel.org, david@redhat.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Qian Cai Subject: [PATCH -mm] mm/page_isolation: fix potential warning from user Date: Sun, 19 Jan 2020 22:42:52 -0500 Message-Id: <20200120034252.1558-1-cai@lca.pw> X-Mailer: git-send-email 2.21.0 (Apple Git-122.2) MIME-Version: 1.0 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: It makes sense to call the WARN_ON_ONCE(zone_idx(zone) =3D=3D ZONE_MOVABL= E) from the offlining path, but should avoid triggering it from userspace, i.e, from is_mem_section_removable(). While at it, simplify the code a bit by removing an unnecessary jump label and a local variable, so set_migratetype_isolate() could really return a bool. Suggested-by: Michal Hocko Signed-off-by: Qian Cai --- mm/page_alloc.c | 11 ++++------- mm/page_isolation.c | 31 ++++++++++++++++++------------- 2 files changed, 22 insertions(+), 20 deletions(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 621716a25639..3c4eb750a199 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -8231,7 +8231,7 @@ struct page *has_unmovable_pages(struct zone *zone,= struct page *page, if (is_migrate_cma(migratetype)) return NULL; =20 - goto unmovable; + return page; } =20 for (; iter < pageblock_nr_pages; iter++) { @@ -8241,7 +8241,7 @@ struct page *has_unmovable_pages(struct zone *zone,= struct page *page, page =3D pfn_to_page(pfn + iter); =20 if (PageReserved(page)) - goto unmovable; + return page; =20 /* * If the zone is movable and we have ruled out all reserved @@ -8261,7 +8261,7 @@ struct page *has_unmovable_pages(struct zone *zone,= struct page *page, unsigned int skip_pages; =20 if (!hugepage_migration_supported(page_hstate(head))) - goto unmovable; + return page; =20 skip_pages =3D compound_nr(head) - (page - head); iter +=3D skip_pages - 1; @@ -8303,12 +8303,9 @@ struct page *has_unmovable_pages(struct zone *zone= , struct page *page, * is set to both of a memory hole page and a _used_ kernel * page at boot. */ - goto unmovable; + return page; } return NULL; -unmovable: - WARN_ON_ONCE(zone_idx(zone) =3D=3D ZONE_MOVABLE); - return pfn_to_page(pfn + iter); } =20 #ifdef CONFIG_CONTIG_ALLOC diff --git a/mm/page_isolation.c b/mm/page_isolation.c index e70586523ca3..97f673d5fefa 100644 --- a/mm/page_isolation.c +++ b/mm/page_isolation.c @@ -15,12 +15,12 @@ #define CREATE_TRACE_POINTS #include =20 -static int set_migratetype_isolate(struct page *page, int migratetype, i= nt isol_flags) +static bool set_migratetype_isolate(struct page *page, int migratetype, + int isol_flags) { - struct page *unmovable =3D NULL; + struct page *unmovable =3D ERR_PTR(-EBUSY); struct zone *zone; unsigned long flags; - int ret =3D -EBUSY; =20 zone =3D page_zone(page); =20 @@ -49,21 +49,26 @@ static int set_migratetype_isolate(struct page *page,= int migratetype, int isol_ NULL); =20 __mod_zone_freepage_state(zone, -nr_pages, mt); - ret =3D 0; } =20 out: spin_unlock_irqrestore(&zone->lock, flags); - if (!ret) + + if (!unmovable) { drain_all_pages(zone); - else if ((isol_flags & REPORT_FAILURE) && unmovable) - /* - * printk() with zone->lock held will guarantee to trigger a - * lockdep splat, so defer it here. - */ - dump_page(unmovable, "unmovable page"); - - return ret; + } else { + if (isol_flags & MEMORY_OFFLINE) + WARN_ON_ONCE(zone_idx(zone) =3D=3D ZONE_MOVABLE); + + if ((isol_flags & REPORT_FAILURE) && !IS_ERR(unmovable)) + /* + * printk() with zone->lock held will likely trigger a + * lockdep splat, so defer it here. + */ + dump_page(unmovable, "unmovable page"); + } + + return !!unmovable; } =20 static void unset_migratetype_isolate(struct page *page, unsigned migrat= etype) --=20 2.21.0 (Apple Git-122.2)