From: Vlastimil Babka <vbabka@suse.cz>
To: Michal Hocko <mhocko@suse.cz>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>,
linux-mm <linux-mm@kvack.org>,
jallen@linux.vnet.ibm.com, qiuxishi@huawei.com,
iamjoonsoo.kim@lge.com, n-horiguchi@ah.jp.nec.com,
rientjes@google.com, Andrew Morton <akpm@linux-foundation.org>,
Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Subject: Re: [PATCH] mem-hotplug: Don't clear the only node in new_node_page()
Date: Tue, 20 Sep 2016 10:31:31 +0200 [thread overview]
Message-ID: <c144f768-7591-8bb8-4238-b3f1ecaf8b4b@suse.cz> (raw)
In-Reply-To: <20160912091811.GE14524@dhcp22.suse.cz>
On 09/12/2016 11:18 AM, Michal Hocko wrote:
> On Mon 05-09-16 16:18:29, Vlastimil Babka wrote:
>
>> Also OOM is skipped for __GFP_THISNODE
>> allocations, so we might also consider the same for nodemask-constrained
>> allocations?
>>
>> > The patch checks whether it is the last node on the system, and if it is, then
>> > don't clear the nid in the nodemask.
>>
>> I'd rather see the allocation not OOM, and rely on the fallback in
>> new_node_page() that doesn't have nodemask. But I suspect it might also make
>> sense to treat empty nodemask as something unexpected and put some WARN_ON
>> (instead of OOM) in the allocator.
>
> To be honest I am really not all that happy about 394e31d2ceb4
> ("mem-hotplug: alloc new page from a nearest neighbor node when
> mem-offline") and find it a bit fishy. I would rather re-iterate that
> patch rather than build new hacks on top.
OK, IIRC I suggested the main idea of clearing the current node from nodemask
and relying on nodelist to get us the other nodes sorted by their distance.
Which I thought was an easy way to get to the theoretically optimal result. How
would you rewrite it then? (but note that the fix is already mainline).
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next prev parent reply other threads:[~2016-09-20 8:31 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-05 2:59 Li Zhong
2016-09-05 14:18 ` Vlastimil Babka
2016-09-06 8:13 ` Li Zhong
2016-09-06 14:12 ` Vlastimil Babka
2016-09-07 0:41 ` [PATCH] mm, page_alloc: warn about empty nodemask Li Zhong
2016-09-08 23:26 ` Andrew Morton
2016-09-09 4:03 ` Li Zhong
2016-09-20 8:27 ` Vlastimil Babka
2016-09-12 9:18 ` [PATCH] mem-hotplug: Don't clear the only node in new_node_page() Michal Hocko
2016-09-20 8:31 ` Vlastimil Babka [this message]
2016-09-20 21:53 ` David Rientjes
2016-09-21 2:11 ` Li Zhong
2016-09-21 8:38 ` [PATCH] mem-hotplug: Use nodes that contain memory as mask " Li Zhong
2016-09-21 9:34 ` Vlastimil Babka
2016-09-21 18:14 ` Michal Hocko
2016-09-21 18:08 ` [PATCH] mem-hotplug: Don't clear the only node " Michal Hocko
2016-09-06 13:16 ` Xishi Qiu
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