From: Michal Hocko <mhocko@kernel.org>
To: Reza Arbab <arbab@linux.vnet.ibm.com>
Cc: Mel Gorman <mgorman@suse.de>,
linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>,
Vlastimil Babka <vbabka@suse.cz>,
Andrea Arcangeli <aarcange@redhat.com>,
Yasuaki Ishimatsu <yasu.isimatu@gmail.com>,
Tang Chen <tangchen@cn.fujitsu.com>,
qiuxishi@huawei.com, Kani Toshimitsu <toshi.kani@hpe.com>,
slaoub@gmail.com, Joonsoo Kim <js1304@gmail.com>,
Andi Kleen <ak@linux.intel.com>,
Zhang Zhen <zhenzhang.zhang@huawei.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>,
Chris Metcalf <cmetcalf@mellanox.com>,
Dan Williams <dan.j.williams@gmail.com>,
Heiko Carstens <heiko.carstens@de.ibm.com>,
Lai Jiangshan <laijs@cn.fujitsu.com>,
Martin Schwidefsky <schwidefsky@de.ibm.com>
Subject: Re: [PATCH 0/6] mm: make movable onlining suck less
Date: Wed, 5 Apr 2017 21:39:34 +0200 [thread overview]
Message-ID: <20170405193933.GW6035@dhcp22.suse.cz> (raw)
In-Reply-To: <20170405181502.GU6035@dhcp22.suse.cz>
On Wed 05-04-17 20:15:02, Michal Hocko wrote:
> On Wed 05-04-17 12:32:49, Reza Arbab wrote:
> > On Wed, Apr 05, 2017 at 05:42:59PM +0200, Michal Hocko wrote:
> > >But one thing that is really bugging me is how could you see low pfns in
> > >the previous oops. Please drop the last patch and sprinkle printks down
> > >the remove_memory path to see where this all go south. I believe that
> > >there is something in the initialization code lurking in my code. Please
> > >also scratch the pfn_valid check in online_pages diff. It will not help
> > >here.
> >
> > Got it.
> >
> > shrink_pgdat_span: start_pfn=0x10000, end_pfn=0x10100, pgdat_start_pfn=0x0, pgdat_end_pfn=0x20000
> >
> > The problem is that pgdat_start_pfn here should be 0x10000. As you
> > suspected, it never got set. This fixes things for me.
> >
> > diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> > index 623507f..37c1b63 100644
> > --- a/mm/memory_hotplug.c
> > +++ b/mm/memory_hotplug.c
> > @@ -884,7 +884,7 @@ static void __meminit resize_pgdat_range(struct pglist_data *pgdat, unsigned lon
> > {
> > unsigned long old_end_pfn = pgdat_end_pfn(pgdat);
> >
> > - if (start_pfn < pgdat->node_start_pfn)
> > + if (!pgdat->node_spanned_pages || start_pfn < pgdat->node_start_pfn)
> > pgdat->node_start_pfn = start_pfn;
>
> Dang! You are absolutely right. This explains the issue during the
> remove_memory. I still fail to see how this makes any difference for the
> sysfs file registration though. If anything the pgdat will be larger and
> so try_offline_node would check also unrelated node0 but the code will
> handle that and eventually offline the node1 anyway. /me still confused.
OK, so I've managed to convince my kvm setup to create a node without
any memory initially but I cannot seem to be able to reach
node_set_offline in try_offline_node because check_and_unmap_cpu_on_node
fails for me even when I offline cpus bound to the node because we are
using for_each_present_cpu in check_cpu_on_node so I would have to start
with a cpuless node or find a way how to hotremove those cpus.
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2017-04-05 19:39 UTC|newest]
Thread overview: 70+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-30 11:54 [PATCH 0/6] mm: make movable onlining suck less Michal Hocko
2017-03-30 11:54 ` [PATCH 1/6] mm: get rid of zone_is_initialized Michal Hocko
2017-03-31 3:39 ` Hillf Danton
2017-03-31 6:43 ` Michal Hocko
2017-03-31 6:48 ` Michal Hocko
2017-03-31 7:39 ` [PATCH v1 " Michal Hocko
2017-04-05 8:14 ` Michal Hocko
2017-04-05 9:06 ` Igor Mammedov
2017-04-05 9:23 ` Michal Hocko
2017-03-30 11:54 ` [PATCH 2/6] mm, tile: drop arch_{add,remove}_memory Michal Hocko
2017-03-30 15:41 ` Chris Metcalf
2017-03-30 11:54 ` [PATCH 3/6] mm: remove return value from init_currently_empty_zone Michal Hocko
2017-03-31 3:49 ` Hillf Danton
2017-03-31 6:49 ` Michal Hocko
2017-03-31 7:06 ` Hillf Danton
2017-03-31 7:18 ` Michal Hocko
2017-03-31 7:43 ` Michal Hocko
2017-04-03 21:22 ` Reza Arbab
2017-04-04 7:30 ` Michal Hocko
2017-03-30 11:54 ` [PATCH 4/6] mm, memory_hotplug: use node instead of zone in can_online_high_movable Michal Hocko
2017-03-30 11:54 ` [PATCH 5/6] mm, memory_hotplug: do not associate hotadded memory to zones until online Michal Hocko
2017-03-31 6:18 ` Hillf Danton
2017-03-31 6:50 ` Michal Hocko
2017-04-04 12:21 ` Tobias Regnery
2017-04-04 12:45 ` Michal Hocko
2017-04-06 8:14 ` Michal Hocko
2017-04-06 12:46 ` Michal Hocko
2017-03-30 11:54 ` [PATCH 6/6] mm, memory_hotplug: remove unused cruft after memory hotplug rework Michal Hocko
2017-03-31 7:46 ` Michal Hocko
2017-03-31 19:19 ` [PATCH 0/6] mm: make movable onlining suck less Heiko Carstens
2017-04-03 7:34 ` Michal Hocko
2017-04-03 11:55 ` Michal Hocko
2017-04-03 12:20 ` Igor Mammedov
2017-04-03 19:58 ` Reza Arbab
2017-04-03 20:23 ` Michal Hocko
2017-04-03 20:42 ` Reza Arbab
2017-04-04 7:23 ` Michal Hocko
2017-04-04 7:34 ` Michal Hocko
2017-04-04 8:23 ` Michal Hocko
2017-04-04 15:59 ` Reza Arbab
2017-04-04 16:02 ` Reza Arbab
2017-04-04 16:44 ` Michal Hocko
2017-04-04 18:30 ` Reza Arbab
2017-04-04 19:41 ` Michal Hocko
2017-04-04 21:43 ` Reza Arbab
2017-04-05 6:42 ` Michal Hocko
2017-04-05 9:24 ` Michal Hocko
2017-04-05 14:53 ` Reza Arbab
2017-04-05 15:42 ` Michal Hocko
2017-04-05 17:32 ` Reza Arbab
2017-04-05 18:15 ` Michal Hocko
2017-04-05 19:39 ` Michal Hocko [this message]
2017-04-05 21:02 ` Michal Hocko
2017-04-06 11:07 ` Michal Hocko
2017-04-05 15:48 ` Reza Arbab
2017-04-05 16:34 ` Michal Hocko
2017-04-05 20:55 ` Reza Arbab
2017-04-06 9:25 ` Michal Hocko
2017-04-05 13:52 ` Michal Hocko
2017-04-05 15:23 ` Reza Arbab
2017-04-05 6:36 ` Michal Hocko
2017-04-06 13:08 ` Michal Hocko
2017-04-06 15:24 ` Reza Arbab
2017-04-06 15:41 ` Michal Hocko
2017-04-06 15:46 ` Reza Arbab
2017-04-06 16:21 ` Michal Hocko
2017-04-06 16:24 ` Mel Gorman
2017-04-06 16:55 ` Mel Gorman
2017-04-06 17:12 ` Michal Hocko
2017-04-06 17:46 ` Mel Gorman
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