From: Michal Hocko <mhocko@kernel.org> To: Wei Yang <richard.weiyang@gmail.com> Cc: Linux-MM <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>, Reza Arbab <arbab@linux.vnet.ibm.com>, Yasuaki Ishimatsu <yasu.isimatu@gmail.com>, Xishi Qiu <qiuxishi@huawei.com>, Kani Toshimitsu <toshi.kani@hpe.com>, slaoub@gmail.com, Joonsoo Kim <js1304@gmail.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: [PATCH 2/2] mm, memory_hotplug: remove zone restrictions Date: Fri, 7 Jul 2017 14:41:12 +0200 [thread overview] Message-ID: <20170707124112.GB16187@dhcp22.suse.cz> (raw) In-Reply-To: <20170707083723.GA19821@WeideMacBook-Pro.local> On Fri 07-07-17 16:37:23, Wei Yang wrote: > On Thu, Jul 06, 2017 at 08:56:50AM +0200, Michal Hocko wrote: > >> Below is a result with a little changed kernel to show the start_pfn always. > >> The sequence is: > >> 1. bootup > >> > >> Node 0, zone Movable > >> spanned 65536 > >> present 0 > >> managed 0 > >> start_pfn: 0 > >> > >> 2. online movable 2 continuous memory_blocks > >> > >> Node 0, zone Movable > >> spanned 65536 > >> present 65536 > >> managed 65536 > >> start_pfn: 1310720 > >> > >> 3. offline 2nd memory_blocks > >> > >> Node 0, zone Movable > >> spanned 65536 > >> present 32768 > >> managed 32768 > >> start_pfn: 1310720 > >> > >> 4. offline 1st memory_blocks > >> > >> Node 0, zone Movable > >> spanned 65536 > >> present 0 > >> managed 0 > >> start_pfn: 1310720 > >> > >> So I am not sure this is still clearly defined? > > > >Could you be more specific what is not clearly defined? You have > >offlined all online memory blocks so present/managed is 0 while the > >spanned is unchanged because the zone is still defined in range > >[1310720, 1376256]. > > > > The zone is empty after remove these two memory blocks, while we still think > it is defined in range [1310720, 1376256]. Yes and present/managed shows that the zone is empty. It's range spans some range but there are no online pages. > This is what I want to point. As I've said several times already. This is somemething that _could_ be fixed but I would rather not to do so until there is a _readl_ usecase which would depend on it. Especially when we can online any memory block to the zone you like. We should really strive to reduce the amount of code rather than keep it just in case without anybody actually using it. -- Michal Hocko SUSE Labs
WARNING: multiple messages have this Message-ID (diff)
From: Michal Hocko <mhocko@kernel.org> To: Wei Yang <richard.weiyang@gmail.com> Cc: Linux-MM <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>, Reza Arbab <arbab@linux.vnet.ibm.com>, Yasuaki Ishimatsu <yasu.isimatu@gmail.com>, Xishi Qiu <qiuxishi@huawei.com>, Kani Toshimitsu <toshi.kani@hpe.com>, slaoub@gmail.com, Joonsoo Kim <js1304@gmail.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: [PATCH 2/2] mm, memory_hotplug: remove zone restrictions Date: Fri, 7 Jul 2017 14:41:12 +0200 [thread overview] Message-ID: <20170707124112.GB16187@dhcp22.suse.cz> (raw) In-Reply-To: <20170707083723.GA19821@WeideMacBook-Pro.local> On Fri 07-07-17 16:37:23, Wei Yang wrote: > On Thu, Jul 06, 2017 at 08:56:50AM +0200, Michal Hocko wrote: > >> Below is a result with a little changed kernel to show the start_pfn always. > >> The sequence is: > >> 1. bootup > >> > >> Node 0, zone Movable > >> spanned 65536 > >> present 0 > >> managed 0 > >> start_pfn: 0 > >> > >> 2. online movable 2 continuous memory_blocks > >> > >> Node 0, zone Movable > >> spanned 65536 > >> present 65536 > >> managed 65536 > >> start_pfn: 1310720 > >> > >> 3. offline 2nd memory_blocks > >> > >> Node 0, zone Movable > >> spanned 65536 > >> present 32768 > >> managed 32768 > >> start_pfn: 1310720 > >> > >> 4. offline 1st memory_blocks > >> > >> Node 0, zone Movable > >> spanned 65536 > >> present 0 > >> managed 0 > >> start_pfn: 1310720 > >> > >> So I am not sure this is still clearly defined? > > > >Could you be more specific what is not clearly defined? You have > >offlined all online memory blocks so present/managed is 0 while the > >spanned is unchanged because the zone is still defined in range > >[1310720, 1376256]. > > > > The zone is empty after remove these two memory blocks, while we still think > it is defined in range [1310720, 1376256]. Yes and present/managed shows that the zone is empty. It's range spans some range but there are no online pages. > This is what I want to point. As I've said several times already. This is somemething that _could_ be fixed but I would rather not to do so until there is a _readl_ usecase which would depend on it. Especially when we can online any memory block to the zone you like. We should really strive to reduce the amount of code rather than keep it just in case without anybody actually using it. -- 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:[~2017-07-07 12:41 UTC|newest] Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top 2017-06-29 7:35 [RFC PATCH 0/2] mm, memory_hotplug: remove zone onlining restriction Michal Hocko 2017-06-29 7:35 ` Michal Hocko 2017-06-29 7:35 ` [PATCH 1/2] mm, memory_hotplug: display allowed zones in the preferred ordering Michal Hocko 2017-06-29 7:35 ` Michal Hocko 2017-06-30 0:45 ` Joonsoo Kim 2017-06-30 0:45 ` Joonsoo Kim 2017-07-07 14:34 ` Vlastimil Babka 2017-07-07 14:34 ` Vlastimil Babka 2017-06-29 7:35 ` [PATCH 2/2] mm, memory_hotplug: remove zone restrictions Michal Hocko 2017-06-29 7:35 ` Michal Hocko 2017-06-30 1:16 ` Joonsoo Kim 2017-06-30 1:16 ` Joonsoo Kim 2017-06-30 3:09 ` Wei Yang 2017-06-30 3:09 ` Wei Yang 2017-06-30 8:39 ` Michal Hocko 2017-06-30 8:39 ` Michal Hocko 2017-06-30 9:39 ` Wei Yang 2017-06-30 9:39 ` Wei Yang 2017-06-30 9:55 ` Michal Hocko 2017-06-30 9:55 ` Michal Hocko 2017-06-30 11:01 ` Michal Hocko 2017-06-30 11:01 ` Michal Hocko 2017-07-05 23:16 ` Wei Yang 2017-07-06 6:56 ` Michal Hocko 2017-07-06 6:56 ` Michal Hocko 2017-07-07 8:37 ` Wei Yang 2017-07-07 12:41 ` Michal Hocko [this message] 2017-07-07 12:41 ` Michal Hocko 2017-07-07 15:02 ` Vlastimil Babka 2017-07-07 15:02 ` Vlastimil Babka 2017-07-10 6:45 ` Michal Hocko 2017-07-10 6:45 ` Michal Hocko 2017-07-10 11:11 ` Vlastimil Babka 2017-07-10 11:11 ` Vlastimil Babka 2017-07-10 11:17 ` Michal Hocko 2017-07-10 11:17 ` Michal Hocko 2017-07-10 12:12 ` Vlastimil Babka 2017-07-10 12:12 ` Vlastimil Babka 2017-07-10 12:30 ` Michal Hocko 2017-07-10 12:30 ` Michal Hocko 2017-07-12 12:49 ` Michal Hocko 2017-07-12 12:49 ` Michal Hocko 2017-07-14 12:12 [PATCH 0/2] mm, memory_hotplug: remove zone onlining restriction Michal Hocko 2017-07-14 12:12 ` [PATCH 2/2] mm, memory_hotplug: remove zone restrictions Michal Hocko 2017-07-14 12:12 ` Michal Hocko 2017-07-14 12:17 ` Vlastimil Babka 2017-07-14 12:17 ` Vlastimil Babka 2017-07-14 14:26 ` Reza Arbab 2017-07-14 14:26 ` Reza Arbab
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