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=-8.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 60D9CC2D0CD for ; Wed, 18 Dec 2019 04:05:17 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 2F32F2146E for ; Wed, 18 Dec 2019 04:05:17 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2F32F2146E Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ellerman.id.au Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id C000C8E00CB; Tue, 17 Dec 2019 23:05:16 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id AED5D8E0079; Tue, 17 Dec 2019 23:05:16 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 966218E00CB; Tue, 17 Dec 2019 23:05:16 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0232.hostedemail.com [216.40.44.232]) by kanga.kvack.org (Postfix) with ESMTP id 807548E0079 for ; Tue, 17 Dec 2019 23:05:16 -0500 (EST) Received: from smtpin27.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with SMTP id 24B89181AEF07 for ; Wed, 18 Dec 2019 04:05:16 +0000 (UTC) X-FDA: 76276922232.27.fly46_853eabc0c350b X-HE-Tag: fly46_853eabc0c350b X-Filterd-Recvd-Size: 2834 Received: from ozlabs.org (ozlabs.org [203.11.71.1]) by imf40.hostedemail.com (Postfix) with ESMTP for ; Wed, 18 Dec 2019 04:05:15 +0000 (UTC) Received: by ozlabs.org (Postfix, from userid 1034) id 47d1cl32N3z9sSF; Wed, 18 Dec 2019 15:05:11 +1100 (AEDT) X-powerpc-patch-notification: thanks X-powerpc-patch-commit: e352f576d345e5bf1fb62c8559851448a6c1d9cd In-Reply-To: <20191216103058.4958-1-david@redhat.com> To: David Hildenbrand , linux-kernel@vger.kernel.org From: Michael Ellerman Cc: David Hildenbrand , Greg Kroah-Hartman , Richard Fontana , linux-mm@kvack.org, Paul Mackerras , Arun KS , Andrew Morton , linuxppc-dev@lists.ozlabs.org, Thomas Gleixner Subject: Re: [PATCH v2] powerpc/pseries/cmm: fix managed page counts when migrating pages between zones Message-Id: <47d1cl32N3z9sSF@ozlabs.org> Date: Wed, 18 Dec 2019 15:05:11 +1100 (AEDT) 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: On Mon, 2019-12-16 at 10:30:58 UTC, David Hildenbrand wrote: > Commit 63341ab03706 (virtio-balloon: fix managed page counts when migrati= > ng > pages between zones) fixed a long existing BUG in the virtio-balloon > driver when pages would get migrated between zones. I did not try to > reproduce on powerpc, but looking at the code, the same should apply to > powerpc/cmm ever since it started using the balloon compaction > infrastructure (luckily just recently). > > In case we have to migrate a ballon page to a newpage of another zone, th= > e > managed page count of both zones is wrong. Paired with memory offlining > (which will adjust the managed page count), we can trigger kernel crashes > and all kinds of different symptoms. > > Fix it by properly adjusting the managed page count when migrating if > the zone changed. > > We'll temporarily modify the totalram page count. If this ever becomes a > problem, we can fine tune by providing helpers that don't touch > the totalram pages (e.g., adjust_zone_managed_page_count()). > > Fixes: fe030c9b85e6 ("powerpc/pseries/cmm: Implement balloon compaction") > Cc: Benjamin Herrenschmidt > Cc: Paul Mackerras > Cc: Michael Ellerman > Cc: Andrew Morton > Cc: Richard Fontana > Cc: Greg Kroah-Hartman > Cc: Arun KS > Cc: Thomas Gleixner > Cc: linuxppc-dev@lists.ozlabs.org > Signed-off-by: David Hildenbrand Applied to powerpc fixes, thanks. https://git.kernel.org/powerpc/c/e352f576d345e5bf1fb62c8559851448a6c1d9cd cheers