Skip to content

Commit

Permalink
mm, slab: split out the cpu offline variant of flush_slab()
Browse files Browse the repository at this point in the history
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 <efault@gmx.de>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
  • Loading branch information
tehcaster committed Sep 3, 2021
1 parent 0e7ac73 commit 08beb54
Showing 1 changed file with 10 additions and 2 deletions.
12 changes: 10 additions & 2 deletions mm/slub.c
Original file line number Diff line number Diff line change
Expand Up @@ -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);
}
Expand Down

0 comments on commit 08beb54

Please sign in to comment.