Messages in this thread | | | Date | Sat, 23 Jun 2012 03:34:27 +0900 | Subject | Re: [PATCH 4/4] slub: deactivate freelist of kmem_cache_cpu all at once in deactivate_slab() | From | JoonSoo Kim <> |
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2012/6/10 JoonSoo Kim <js1304@gmail.com>: > 2012/6/9 Christoph Lameter <cl@linux.com>: >> On Sat, 9 Jun 2012, Joonsoo Kim wrote: >> >>> Current implementation of deactivate_slab() which deactivate >>> freelist of kmem_cache_cpu one by one is inefficient. >>> This patch changes it to deactivate freelist all at once. >>> But, there is no overall performance benefit, >>> because deactivate_slab() is invoked infrequently. >> >> Hmm, deactivate freelist can race with slab_free. Need to look at this in >> detail. > > Implemented logic is nearly same as previous one. > I just merge first step of previous deactivate_slab() with second one. > In case of failure of cmpxchg_double_slab(), reloading page->freelist, > page->counters and recomputing inuse > ensure that race with slab_free() cannot be possible. > In case that we need a lock, try to get a lock before invoking > cmpxchg_double_slab(), > so race with slab_free cannot be occured too. > > Above is my humble opinion, please give me some comments.
Hi Pekka and Christoph. Could you give me some comments about this, please?
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