From 08beb547a1f7b66fbeaf40f2d3675a3ea0060c0b Mon Sep 17 00:00:00 2001 From: Vlastimil Babka Date: Thu, 3 Jun 2021 19:17:42 +0200 Subject: [PATCH] mm, slab: split out the cpu offline variant of flush_slab() flush_slab() is called either as part IPI handler on given live cpu, or as a cleanup on behalf of another cpu that went offline. The first case needs to protect updating the kmem_cache_cpu fields with disabled irqs. Currently the whole call happens with irqs disabled by the IPI handler, but the following patch will change from IPI to workqueue, and flush_slab() will have to disable irqs (to be replaced with a local lock later) in the critical part. To prepare for this change, replace the call to flush_slab() for the dead cpu handling with an opencoded variant that will not disable irqs nor take a local lock. Suggested-by: Mike Galbraith Signed-off-by: Vlastimil Babka --- mm/slub.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/mm/slub.c b/mm/slub.c index c4a9b8901576ba..fa9a366d2d9c18 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -2511,9 +2511,17 @@ static inline void flush_slab(struct kmem_cache *s, struct kmem_cache_cpu *c) static inline void __flush_cpu_slab(struct kmem_cache *s, int cpu) { struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu); + void *freelist = c->freelist; + struct page *page = c->page; - if (c->page) - flush_slab(s, c); + c->page = NULL; + c->freelist = NULL; + c->tid = next_tid(c->tid); + + if (page) { + deactivate_slab(s, page, freelist); + stat(s, CPUSLAB_FLUSH); + } unfreeze_partials_cpu(s, c); }