From: David Hildenbrand <david@redhat.com>
To: Michal Hocko <mhocko@suse.com>
Cc: Alexey Makhalov <amakhalov@vmware.com>,
Dennis Zhou <dennis@kernel.org>,
Eric Dumazet <eric.dumazet@gmail.com>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
Andrew Morton <akpm@linux-foundation.org>,
Oscar Salvador <osalvador@suse.de>, Tejun Heo <tj@kernel.org>,
Christoph Lameter <cl@linux.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"stable@vger.kernel.org" <stable@vger.kernel.org>
Subject: Re: [PATCH v3] mm: fix panic in __alloc_pages
Date: Tue, 7 Dec 2021 13:28:31 +0100 [thread overview]
Message-ID: <ab5cfba0-1d49-4e4d-e2c8-171e24473c1b@redhat.com> (raw)
In-Reply-To: <Ya9P5NxhcZDcyptT@dhcp22.suse.cz>
>>> + free_area_init_memoryless_node(nid);
>>
>> That's really just free_area_init_node() below, I do wonder what value
>> free_area_init_memoryless_node() has as of today.
>
> I am not sure there is any real value in having this special name for
> this but I have kept is sync with what x86 does currently. If we want to
> remove the wrapper then just do it everywhere. I can do that on top.
>
Sure, just a general comment.
>>> + continue;
>>> + }
>>> +
>>> free_area_init_node(nid);
>>>
>>> /* Any memory on that node */
>>>
>>> Could you give it a try? I do not have any machine which would exhibit
>>> the problem so I cannot really test this out. I hope build_zone_info
>>> will not choke on this. I assume the node distance table is
>>> uninitialized for these nodes and IIUC this should lead to an assumption
>>> that all other nodes are close. But who knows that can blow up there.
>>>
>>> Btw. does this make any sense at all to others?
>>>
>>
>> __build_all_zonelists() has to update the zonelists of all nodes I think.
>
> I am not sure what you mean. This should be achieved by this patch
> because the boot time build_all_zonelists will go over all online nodes
"Over all possible nodes", including online and offline ones, to make
sure any possible node has a valid pgdat. IIUC, you're not changing
anything about online vs offline nodes, only that we have a pgdat also
for offline nodes.
> (i.e. with pgdat). free_area_init happens before that. I am just worried
> that the arch specific node_distance() will generate a complete garbage
> or blow up for some reason.
Assume you online a new zone and then call __build_all_zonelists() to
include the zone in all zonelists (via online_pages()).
__build_all_zonelists() will not include offline nodes (that still have
a pgdat with a valid zonelist now).
Similarly, assume you online a zone and then call
__build_all_zonelists() to exclude the zone from all zonelists (via
offline_pages()). __build_all_zonelists() will not include offline nodes
(that still have a pgdat with a valid zonelist now).
Essentially, IIRC, even after your change
start_kernel()->build_all_zonelists(NULL)->build_all_zonelists_init()->__build_all_zonelists(NULL)
won't initialize the zonelist of the new pgdat, because the nodes are
offline.
I'd assume we'd need
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index c5952749ad40..e5d958abc7cc 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -6382,7 +6382,7 @@ static void __build_all_zonelists(void *data)
if (self && !node_online(self->node_id)) {
build_zonelists(self);
} else {
- for_each_online_node(nid) {
+ for_each_node(nid) {
pg_data_t *pgdat = NODE_DATA(nid);
build_zonelists(pgdat);
to properly initialize the zonelist also for the offline nodes with a
valid pgdat.
But maybe I am missing something important regarding online vs. offline
nodes that your patch changes?
--
Thanks,
David / dhildenb
next prev parent reply other threads:[~2021-12-07 12:28 UTC|newest]
Thread overview: 98+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-01 20:13 [PATCH] mm: fix panic in __alloc_pages Alexey Makhalov
2021-11-01 20:38 ` Matthew Wilcox
2021-11-02 7:47 ` Michal Hocko
2021-11-02 8:12 ` David Hildenbrand
2021-11-02 8:48 ` Alexey Makhalov
2021-11-02 9:04 ` Michal Hocko
2021-11-02 9:24 ` David Hildenbrand
2021-11-02 10:34 ` Alexey Makhalov
2021-11-02 11:00 ` David Hildenbrand
2021-11-02 11:44 ` Michal Hocko
2021-11-02 12:06 ` David Hildenbrand
2021-11-02 12:27 ` Michal Hocko
2021-11-02 12:39 ` David Hildenbrand
2021-11-02 13:25 ` Michal Hocko
2021-11-02 13:41 ` David Hildenbrand
2021-11-02 14:12 ` Michal Hocko
2021-11-02 14:44 ` David Hildenbrand
2021-11-02 13:52 ` Oscar Salvador
2021-11-02 14:35 ` Michal Hocko
2021-11-08 6:12 ` Alexey Makhalov
2021-11-08 6:36 ` [PATCH v2] " Alexey Makhalov
2021-11-08 8:32 ` David Hildenbrand
2021-11-08 20:23 ` [PATCH v3] " Alexey Makhalov
2021-11-09 2:08 ` Eric Dumazet
2021-11-09 7:03 ` David Hildenbrand
2021-11-09 16:55 ` Eric Dumazet
2021-11-09 17:15 ` Michal Hocko
2021-11-09 19:06 ` Dennis Zhou
2021-11-09 19:54 ` Michal Hocko
2021-11-16 1:31 ` Alexey Makhalov
2021-11-16 9:17 ` Michal Hocko
2021-11-16 20:22 ` Alexey Makhalov
2021-11-18 8:35 ` Michal Hocko
2021-12-07 10:54 ` Michal Hocko
2021-12-07 11:08 ` David Hildenbrand
2021-12-07 12:13 ` Michal Hocko
2021-12-07 12:28 ` David Hildenbrand [this message]
2021-12-07 13:23 ` Michal Hocko
2021-12-07 15:09 ` David Hildenbrand
2021-12-07 15:29 ` Michal Hocko
2021-12-07 15:34 ` David Hildenbrand
2021-12-07 15:56 ` Michal Hocko
2021-12-07 16:09 ` David Hildenbrand
2021-12-07 16:27 ` Michal Hocko
2021-12-07 16:36 ` Michal Hocko
2021-12-07 16:40 ` David Hildenbrand
2021-12-08 8:28 ` Michal Hocko
2021-12-07 17:02 ` Alexey Makhalov
2021-12-07 17:13 ` David Hildenbrand
2021-12-07 17:17 ` Alexey Makhalov
2021-12-07 18:03 ` David Hildenbrand
2021-12-08 8:12 ` Michal Hocko
2021-12-08 8:24 ` David Hildenbrand
2021-12-08 8:34 ` Michal Hocko
2021-12-08 8:38 ` David Hildenbrand
2021-12-08 8:04 ` Michal Hocko
2021-12-08 8:19 ` Alexey Makhalov
2021-12-08 8:30 ` Michal Hocko
2021-12-08 8:54 ` Michal Hocko
2021-12-08 8:57 ` Alexey Makhalov
2021-12-08 9:55 ` Michal Hocko
2021-12-09 2:16 ` Alexey Makhalov
2021-12-09 8:46 ` Michal Hocko
2021-12-09 9:28 ` Alexey Makhalov
2021-12-09 9:56 ` Michal Hocko
2021-12-09 10:23 ` Alexey Makhalov
2021-12-09 13:29 ` Michal Hocko
2021-12-09 19:01 ` Alexey Makhalov
2021-12-10 9:11 ` Michal Hocko
2021-12-17 12:53 ` Michal Hocko
2021-12-21 5:46 ` Alexey Makhalov
2021-12-21 9:46 ` Michal Hocko
2021-12-21 20:23 ` Alexey Makhalov
2021-12-22 11:41 ` Michal Hocko
2021-12-09 10:48 ` Michal Hocko
2021-12-13 15:06 ` Michal Hocko
2021-12-13 15:07 ` David Hildenbrand
2021-12-14 8:38 ` Michal Hocko
2021-12-14 10:07 ` [PATCH v2 0/4] mm, memory_hotplug: handle unitialized numa node gracefully Michal Hocko
2021-12-14 10:07 ` [PATCH v2 1/4] mm, memory_hotplug: make arch_alloc_nodedata independent on CONFIG_MEMORY_HOTPLUG Michal Hocko
2021-12-14 10:07 ` [PATCH v2 2/4] mm: handle uninitialized numa nodes gracefully Michal Hocko
2021-12-14 10:33 ` Christoph Lameter
2021-12-14 10:38 ` Michal Hocko
2022-01-14 0:24 ` Wei Yang
2022-01-14 10:01 ` Michal Hocko
2021-12-15 4:47 ` kernel test robot
2021-12-15 10:12 ` Michal Hocko
2021-12-14 10:07 ` [PATCH v2 3/4] mm, memory_hotplug: drop arch_free_nodedata Michal Hocko
2021-12-14 10:07 ` [PATCH v2 4/4] mm, memory_hotplug: reorganize new pgdat initialization Michal Hocko
2021-12-17 14:51 ` [PATCH v2 0/4] mm, memory_hotplug: handle unitialized numa node gracefully David Hildenbrand
2021-12-21 9:51 ` Michal Hocko
2022-01-02 7:14 ` Mike Rapoport
2022-01-10 17:16 ` Michal Hocko
2022-01-10 21:16 ` Rafael Aquini
2022-01-11 8:34 ` Michal Hocko
2021-11-08 10:37 ` [PATCH v2] mm: fix panic in __alloc_pages Michal Hocko
2021-11-02 9:40 ` [PATCH] " Alexey Makhalov
2021-11-02 9:40 ` Michal Hocko
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