mm, slub: move irq control into unfreeze_partials()

unfreeze_partials() can be optimized so that it doesn't need irqs disabled for
the whole time. As the first step, move irq control into the function and
remove it from the put_cpu_partial() caller.

Signed-off-by: Vlastimil Babka <vbabka@suse.cz>

diff --git a/mm/slub.c b/mm/slub.c
index cb12a07..1c4bd45 100644 (file)
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -2350,9 +2350,8 @@ redo:
 /*
  * Unfreeze all the cpu partial slabs.
  *
- * This function must be called with interrupts disabled
- * for the cpu using c (or some other guarantee must be there
- * to guarantee no concurrent accesses).
+ * This function must be called with preemption or migration
+ * disabled with c local to the cpu.
  */
 static void unfreeze_partials(struct kmem_cache *s,
                struct kmem_cache_cpu *c)
@@ -2360,6 +2359,9 @@ static void unfreeze_partials(struct kmem_cache *s,
 #ifdef CONFIG_SLUB_CPU_PARTIAL
        struct kmem_cache_node *n = NULL, *n2 = NULL;
        struct page *page, *discard_page = NULL;
+       unsigned long flags;
+
+       local_irq_save(flags);
 
        while ((page = slub_percpu_partial(c))) {
                struct page new;
@@ -2412,6 +2414,8 @@ static void unfreeze_partials(struct kmem_cache *s,
                discard_slab(s, page);
                stat(s, FREE_SLAB);
        }
+
+       local_irq_restore(flags);
 #endif /* CONFIG_SLUB_CPU_PARTIAL */
 }
 
@@ -2439,14 +2443,11 @@ static void put_cpu_partial(struct kmem_cache *s, struct page *page, int drain)
                        pobjects = oldpage->pobjects;
                        pages = oldpage->pages;
                        if (drain && pobjects > slub_cpu_partial(s)) {
-                               unsigned long flags;
                                /*
                                 * partial array is full. Move the existing
                                 * set to the per node partial list.
                                 */
-                               local_irq_save(flags);
                                unfreeze_partials(s, this_cpu_ptr(s->cpu_slab));
-                               local_irq_restore(flags);
                                oldpage = NULL;
                                pobjects = 0;
                                pages = 0;