Re: [PATCH v3 3/7] mm, slab: allocate off-slab freelists as reclaimable when appropriate

From
Mel Gorman <hidden>
Date
2018-07-19 08:35:36
Also in
linux-mm, lkml
Reply to
Vlastimil Babka, 2018-07-18
On Wed, Jul 18, 2018 at 03:36:16PM +0200, Vlastimil Babka wrote:
In SLAB, OFF_SLAB caches allocate management structures (currently just the
freelist) from kmalloc caches when placement in a slab page together with
objects would lead to suboptimal memory usage. For SLAB_RECLAIM_ACCOUNT caches,
we can allocate the freelists from the newly introduced reclaimable kmalloc
caches, because shrinking the OFF_SLAB cache will in general result to freeing
of the freelists as well. This should improve accounting and anti-fragmentation
a bit.

Signed-off-by: Vlastimil Babka <redacted>
I'm not quite convinced by this one. The freelist cache is tied to the
lifetime of the slab and not the objects. A single freelist can be reclaimed
eventually but for caches with many objects per slab, it could take a lot
of shrinking random objects to reclaim one freelist. Functionally the
patch appears to be fine.

-- 
Mel Gorman
SUSE Labs
Thread (26 messages) 26 messages, 4 authors, last reply 2018-07-31
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