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 <vbabka@xxxxxxx> > > 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.
