From: Michal Hocko <mhocko@kernel.org> To: Reza Arbab <arbab@linux.vnet.ibm.com> Cc: linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>, Mel Gorman <mgorman@suse.de>, Vlastimil Babka <vbabka@suse.cz>, Andrea Arcangeli <aarcange@redhat.com>, Jerome Glisse <jglisse@redhat.com>, Yasuaki Ishimatsu <yasu.isimatu@gmail.com>, qiuxishi@huawei.com, Kani Toshimitsu <toshi.kani@hpe.com>, slaoub@gmail.com, Joonsoo Kim <js1304@gmail.com>, Andi Kleen <ak@linux.intel.com>, David Rientjes <rientjes@google.com>, Daniel Kiper <daniel.kiper@oracle.com>, Igor Mammedov <imammedo@redhat.com>, Vitaly Kuznetsov <vkuznets@redhat.com>, LKML <linux-kernel@vger.kernel.org> Subject: Re: [RFC PATCH 1/2] mm, memory_hotplug: drop artificial restriction on online/offline Date: Thu, 25 May 2017 08:28:08 +0200 [thread overview] Message-ID: <20170525062808.GE12721@dhcp22.suse.cz> (raw) In-Reply-To: <20170524215056.h4r3sdk23bn4c2sr@arbab-laptop.localdomain> On Wed 24-05-17 16:50:56, Reza Arbab wrote: > On Wed, May 24, 2017 at 02:24:10PM +0200, Michal Hocko wrote: > >74d42d8fe146 ("memory_hotplug: ensure every online node has NORMAL > >memory") has added can_offline_normal which checks the amount of > >memory in !movable zones as long as CONFIG_MOVABLE_NODE is disable. > >It disallows to offline memory if there is nothing left with a > >justification that "memory-management acts bad when we have nodes which > >is online but don't have any normal memory". > > > >74d42d8fe146 ("memory_hotplug: ensure every online node has NORMAL > >memory") has introduced a restriction that every numa node has to have > >at least some memory in !movable zones before a first movable memory > >can be onlined if !CONFIG_MOVABLE_NODE with the same justification > > > >While it is true that not having _any_ memory for kernel allocations on > >a NUMA node is far from great and such a node would be quite subotimal > >because all kernel allocations will have to fallback to another NUMA > >node but there is no reason to disallow such a configuration in > >principle. > > > >Besides that there is not really a big difference to have one memblock > >for ZONE_NORMAL available or none. With 128MB size memblocks the system > >might trash on the kernel allocations requests anyway. It is really > >hard to draw a line on how much normal memory is really sufficient so > >we have to rely on administrator to configure system sanely therefore > >drop the artificial restriction and remove can_offline_normal and > >can_online_high_movable altogether. > > I'm really liking all this cleanup of the memory hotplug code. Thanks! Much > appreciated. I am glad to hear that and more is to come. > Acked-by: Reza Arbab <arbab@linux.vnet.ibm.com> Thanks! -- Michal Hocko SUSE Labs
WARNING: multiple messages have this Message-ID (diff)
From: Michal Hocko <mhocko@kernel.org> To: Reza Arbab <arbab@linux.vnet.ibm.com> Cc: linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>, Mel Gorman <mgorman@suse.de>, Vlastimil Babka <vbabka@suse.cz>, Andrea Arcangeli <aarcange@redhat.com>, Jerome Glisse <jglisse@redhat.com>, Yasuaki Ishimatsu <yasu.isimatu@gmail.com>, qiuxishi@huawei.com, Kani Toshimitsu <toshi.kani@hpe.com>, slaoub@gmail.com, Joonsoo Kim <js1304@gmail.com>, Andi Kleen <ak@linux.intel.com>, David Rientjes <rientjes@google.com>, Daniel Kiper <daniel.kiper@oracle.com>, Igor Mammedov <imammedo@redhat.com>, Vitaly Kuznetsov <vkuznets@redhat.com>, LKML <linux-kernel@vger.kernel.org> Subject: Re: [RFC PATCH 1/2] mm, memory_hotplug: drop artificial restriction on online/offline Date: Thu, 25 May 2017 08:28:08 +0200 [thread overview] Message-ID: <20170525062808.GE12721@dhcp22.suse.cz> (raw) In-Reply-To: <20170524215056.h4r3sdk23bn4c2sr@arbab-laptop.localdomain> On Wed 24-05-17 16:50:56, Reza Arbab wrote: > On Wed, May 24, 2017 at 02:24:10PM +0200, Michal Hocko wrote: > >74d42d8fe146 ("memory_hotplug: ensure every online node has NORMAL > >memory") has added can_offline_normal which checks the amount of > >memory in !movable zones as long as CONFIG_MOVABLE_NODE is disable. > >It disallows to offline memory if there is nothing left with a > >justification that "memory-management acts bad when we have nodes which > >is online but don't have any normal memory". > > > >74d42d8fe146 ("memory_hotplug: ensure every online node has NORMAL > >memory") has introduced a restriction that every numa node has to have > >at least some memory in !movable zones before a first movable memory > >can be onlined if !CONFIG_MOVABLE_NODE with the same justification > > > >While it is true that not having _any_ memory for kernel allocations on > >a NUMA node is far from great and such a node would be quite subotimal > >because all kernel allocations will have to fallback to another NUMA > >node but there is no reason to disallow such a configuration in > >principle. > > > >Besides that there is not really a big difference to have one memblock > >for ZONE_NORMAL available or none. With 128MB size memblocks the system > >might trash on the kernel allocations requests anyway. It is really > >hard to draw a line on how much normal memory is really sufficient so > >we have to rely on administrator to configure system sanely therefore > >drop the artificial restriction and remove can_offline_normal and > >can_online_high_movable altogether. > > I'm really liking all this cleanup of the memory hotplug code. Thanks! Much > appreciated. I am glad to hear that and more is to come. > Acked-by: Reza Arbab <arbab@linux.vnet.ibm.com> Thanks! -- Michal Hocko SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2017-05-25 6:28 UTC|newest] Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top 2017-05-24 12:24 [RFC PATCH 0/2] remove CONFIG_MOVABLE_NODE Michal Hocko 2017-05-24 12:24 ` Michal Hocko 2017-05-24 12:24 ` [RFC PATCH 1/2] mm, memory_hotplug: drop artificial restriction on online/offline Michal Hocko 2017-05-24 12:24 ` Michal Hocko 2017-05-24 12:44 ` Vlastimil Babka 2017-05-24 12:44 ` Vlastimil Babka 2017-05-24 12:55 ` Michal Hocko 2017-05-24 12:55 ` Michal Hocko 2017-05-24 21:50 ` Reza Arbab 2017-05-24 21:50 ` Reza Arbab 2017-05-25 6:28 ` Michal Hocko [this message] 2017-05-25 6:28 ` Michal Hocko 2017-05-24 12:24 ` [RFC PATCH 2/2] mm, memory_hotplug: drop CONFIG_MOVABLE_NODE Michal Hocko 2017-05-24 12:24 ` Michal Hocko 2017-05-24 12:53 ` Vlastimil Babka 2017-05-24 12:53 ` Vlastimil Babka 2017-05-24 13:42 ` Michal Hocko 2017-05-24 13:42 ` Michal Hocko 2017-05-24 15:17 ` Vlastimil Babka 2017-05-24 15:17 ` Vlastimil Babka 2017-05-25 6:27 ` Michal Hocko 2017-05-25 6:27 ` Michal Hocko 2017-05-25 8:41 ` Vlastimil Babka 2017-05-25 8:41 ` Vlastimil Babka 2017-05-24 13:30 ` Igor Mammedov 2017-05-24 13:30 ` Igor Mammedov 2017-05-24 13:50 ` Michal Hocko 2017-05-24 13:50 ` Michal Hocko 2017-05-24 21:51 ` Reza Arbab 2017-05-24 21:51 ` Reza Arbab 2017-05-25 12:03 ` [RFC PATCH 0/2] remove CONFIG_MOVABLE_NODE Michal Hocko 2017-05-25 12:03 ` Michal Hocko
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