From: David Rientjes <rientjes@google.com>
To: Michal Hocko <mhocko@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Jonathan Corbet <corbet@lwn.net>,
Vlastimil Babka <vbabka@suse.cz>, Mel Gorman <mgorman@suse.de>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
linux-doc@vger.kernel.org
Subject: Re: [patch 1/2] mm, page_alloc: extend kernelcore and movablecore for percent
Date: Wed, 14 Feb 2018 02:28:38 -0800 (PST) [thread overview]
Message-ID: <alpine.DEB.2.10.1802140225290.261065@chino.kir.corp.google.com> (raw)
In-Reply-To: <20180214095911.GB28460@dhcp22.suse.cz>
On Wed, 14 Feb 2018, Michal Hocko wrote:
> I do not have any objections regarding the extension. What I am more
> interested in is _why_ people are still using this command line
> parameter at all these days. Why would anybody want to introduce lowmem
> issues from 32b days. I can see the CMA/Hotplug usecases for
> ZONE_MOVABLE but those have their own ways to define zone movable. I was
> tempted to simply remove the kernelcore already. Could you be more
> specific what is your usecase which triggered a need of an easier
> scaling of the size?
Fragmentation of non-__GFP_MOVABLE pages due to low on memory situations
can pollute most pageblocks on the system, as much as 1GB of slab being
fragmented over 128GB of memory, for example. When the amount of kernel
memory is well bounded for certain systems, it is better to aggressively
reclaim from existing MIGRATE_UNMOVABLE pageblocks rather than eagerly
fallback to others.
We have additional patches that help with this fragmentation if you're
interested, specifically kcompactd compaction of MIGRATE_UNMOVABLE
pageblocks triggered by fallback of non-__GFP_MOVABLE allocations and
draining of pcp lists back to the zone free area to prevent stranding.
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next prev parent reply other threads:[~2018-02-14 10:28 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-13 0:24 David Rientjes
2018-02-13 0:24 ` [patch 2/2] mm, page_alloc: move mirrored_kernelcore to __meminitdata David Rientjes
2018-02-13 23:46 ` [patch 1/2] mm, page_alloc: extend kernelcore and movablecore for percent Andrew Morton
2018-02-13 23:55 ` David Rientjes
2018-02-14 1:14 ` Andrew Morton
2018-02-14 0:37 ` Mike Kravetz
2018-02-14 0:53 ` David Rientjes
2018-02-14 1:00 ` [patch -mm] mm, page_alloc: extend kernelcore and movablecore for percent fix David Rientjes
2018-02-14 1:10 ` Mike Kravetz
2018-02-14 9:59 ` [patch 1/2] mm, page_alloc: extend kernelcore and movablecore for percent Michal Hocko
2018-02-14 10:28 ` David Rientjes [this message]
2018-02-15 14:45 ` Michal Hocko
2018-02-15 15:11 ` Matthew Wilcox
2018-02-15 15:49 ` Christopher Lameter
2018-02-15 20:14 ` Matthew Wilcox
2018-02-16 15:41 ` Christopher Lameter
2018-02-15 20:48 ` Matthew Wilcox
2018-02-16 0:45 ` David Rientjes
2018-02-16 15:44 ` Christopher Lameter
2018-02-16 16:01 ` Matthew Wilcox
2018-02-16 16:08 ` Christopher Lameter
2018-02-16 17:09 ` Matthew Wilcox
2018-02-15 20:47 ` David Rientjes
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