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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Mon, 16 Sep 2019 07:36:16 +0100 Received: from d06av26.portsmouth.uk.ibm.com (d06av26.portsmouth.uk.ibm.com [9.149.105.62]) by b06avi18626390.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x8G6ZnsG44892632 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 16 Sep 2019 06:35:49 GMT Received: from d06av26.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 58C74AE057; Mon, 16 Sep 2019 06:36:15 +0000 (GMT) Received: from d06av26.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 985E4AE051; Mon, 16 Sep 2019 06:36:14 +0000 (GMT) Received: from linux.ibm.com (unknown [9.148.8.160]) by d06av26.portsmouth.uk.ibm.com (Postfix) with ESMTPS; Mon, 16 Sep 2019 06:36:14 +0000 (GMT) Date: Mon, 16 Sep 2019 09:36:12 +0300 From: Mike Rapoport To: Anshuman Khandual Cc: linux-mm@kvack.org, akpm@linux-foundation.org, linux-kernel@vger.kernel.org, Oscar Salvador , Michal Hocko , David Hildenbrand , Pavel Tatashin , Dan Williams Subject: Re: [PATCH] mm/hotplug: Reorder memblock_[free|remove]() calls in try_remove_memory() References: <1568612857-10395-1-git-send-email-anshuman.khandual@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1568612857-10395-1-git-send-email-anshuman.khandual@arm.com> User-Agent: Mutt/1.5.24 (2015-08-30) X-TM-AS-GCONF: 00 x-cbid: 19091606-0008-0000-0000-00000316CAD9 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19091606-0009-0000-0000-00004A3542B2 Message-Id: <20190916063612.GA1502@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-09-16_03:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1908290000 definitions=main-1909160071 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, Sep 16, 2019 at 11:17:37AM +0530, Anshuman Khandual wrote: > In add_memory_resource() the memory range to be hot added first gets into > the memblock via memblock_add() before arch_add_memory() is called on it. > Reverse sequence should be followed during memory hot removal which already > is being followed in add_memory_resource() error path. This now ensures > required re-order between memblock_[free|remove]() and arch_remove_memory() > during memory hot-remove. > > Cc: Andrew Morton > Cc: Oscar Salvador > Cc: Michal Hocko > Cc: David Hildenbrand > Cc: Pavel Tatashin > Cc: Dan Williams > Signed-off-by: Anshuman Khandual > --- > Original patch https://lkml.org/lkml/2019/9/3/327 > > Memory hot remove now works on arm64 without this because a recent commit > 60bb462fc7ad ("drivers/base/node.c: simplify unregister_memory_block_under_nodes()"). > > David mentioned that re-ordering should still make sense for consistency > purpose (removing stuff in the reverse order they were added). This patch > is now detached from arm64 hot-remove series. > > https://lkml.org/lkml/2019/9/3/326 > > mm/memory_hotplug.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c > index c73f09913165..355c466e0621 100644 > --- a/mm/memory_hotplug.c > +++ b/mm/memory_hotplug.c > @@ -1770,13 +1770,13 @@ static int __ref try_remove_memory(int nid, u64 start, u64 size) > > /* remove memmap entry */ > firmware_map_remove(start, start + size, "System RAM"); > - memblock_free(start, size); > - memblock_remove(start, size); > > /* remove memory block devices before removing memory */ > remove_memory_block_devices(start, size); > > arch_remove_memory(nid, start, size, NULL); > + memblock_free(start, size); I don't see memblock_reserve() anywhere in memory_hotplug.c, so the memblock_free() call here seems superfluous. I think it can be simply dropped. > + memblock_remove(start, size); > __release_memory_resource(start, size); > > try_offline_node(nid); > -- > 2.20.1 > > -- Sincerely yours, Mike.