[lkml]   [2018]   [Jul]   [20]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [PATCH v3 3/7] mm, slab: allocate off-slab freelists as reclaimable when appropriate
On 07/19/2018 10:35 AM, Mel Gorman wrote:
> 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 <>
> 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.

Hm you're right that the reclaimability of freelist is maybe too much
detached, and could do more harm than good for the reclaimable caches. I
will probably drop it unless I can measure it's an improvement. Thanks.

 \ /
  Last update: 2018-07-20 11:40    [W:0.072 / U:6.920 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site