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Subject[RFC v2 22/34] mm, slub: move irq control into unfreeze_partials()
Date
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>
---
mm/slub.c | 13 +++++++------
1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/mm/slub.c b/mm/slub.c
index a99a254f2410..4a3cd8174cd2 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -2290,9 +2290,8 @@ static void deactivate_slab(struct kmem_cache *s, struct page *page,
/*
* 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)
@@ -2300,6 +2299,9 @@ 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;
@@ -2352,6 +2354,8 @@ 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 */
}

@@ -2379,14 +2383,11 @@ 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;
--
2.31.1
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