From: Michal Hocko <mhocko@kernel.org>
To: David Hildenbrand <david@redhat.com>
Cc: Wei Yang <richard.weiyang@linux.alibaba.com>,
akpm@linux-foundation.org, osalvador@suse.de,
dan.j.williams@intel.com, linux-mm@kvack.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mm/spase: never partially remove memmap for early section
Date: Wed, 24 Jun 2020 10:50:15 +0200 [thread overview]
Message-ID: <20200624085015.GG1320@dhcp22.suse.cz> (raw)
In-Reply-To: <2b2b722a-58de-4c6e-a04e-dc3516b1b8ab@redhat.com>
On Wed 24-06-20 10:41:18, David Hildenbrand wrote:
[...]
> But nothing actually breaks .... because *drummroll* we use huge pages in the vmemmap,
> so the partial depopulate will not actually depopulate anything here. Huge page is 2M,
> the memmap of 128MB sections is exactly 2MB == one hugepages. Trying to depopulate a
> fraction (e.g., 16MB) of that won't do anything.
>
>
> Now, forcing a CPU without hugepages - PSE (QEMU: "-cpu host,pse=off)", I can trigger
> via ndctl create-namespace --force --reconfig=namespace0.0 --mode=devdax --size=16M
OK, now I am following! Thanks a lot. That is something to be mentioned
in the changelog. Small pages might be used if the hotplug happens on a
system with fragmented memory so this is something we do care about.
Thanks a lot David!
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2020-06-24 8:50 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-23 9:42 [PATCH] mm/spase: never partially remove memmap for early section Wei Yang
2020-06-23 12:44 ` David Hildenbrand
2020-06-23 13:02 ` Wei Yang
2020-06-23 13:16 ` David Hildenbrand
2020-06-23 15:18 ` Michal Hocko
2020-06-23 21:48 ` Wei Yang
2020-06-24 6:13 ` Wei Yang
2020-06-24 16:10 ` Dan Williams
2020-06-24 22:05 ` Wei Yang
2020-06-24 22:20 ` Dan Williams
2020-06-24 22:44 ` Wei Yang
2020-06-24 23:47 ` Dan Williams
2020-06-25 5:53 ` David Hildenbrand
2020-06-25 19:46 ` Dan Williams
2020-06-25 22:29 ` Wei Yang
2020-06-29 8:34 ` Wei Yang
2020-06-29 22:13 ` Dan Williams
2020-06-29 22:58 ` Wei Yang
2020-06-30 7:16 ` David Hildenbrand
2020-06-25 22:39 ` Wei Yang
2020-06-26 4:59 ` David Hildenbrand
2020-06-24 7:48 ` David Hildenbrand
2020-06-24 8:04 ` David Hildenbrand
2020-06-24 8:13 ` Wei Yang
2020-06-24 8:41 ` David Hildenbrand
2020-06-24 8:50 ` Michal Hocko [this message]
2020-06-24 22:27 ` Wei Yang
2020-06-24 0:21 ` Dan Williams
2020-06-24 1:11 ` Wei Yang
2020-06-24 1:47 ` Baoquan He
2020-06-24 2:14 ` Baoquan He
2020-06-24 3:46 ` Wei Yang
2020-06-24 3:52 ` Baoquan He
2020-06-24 3:56 ` Wei Yang
2020-06-24 8:51 ` David Hildenbrand
2020-06-24 22:08 ` Wei Yang
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