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authorVlastimil Babka <vbabka@suse.cz>2021-05-11 17:45:26 +0200
committerVlastimil Babka <vbabka@suse.cz>2021-09-04 01:12:21 +0200
commit4b1f449dedd2ff1eede4ced08a503e13c8d668ce (patch)
treeb62ea094b918c5c85a691a27d01ef9e328dce165 /mm
parent9f101ee89465e0b2c11b477f5b55e03039b2c308 (diff)
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mm, slub: stop disabling irqs around get_partial()
The function get_partial() does not need to have irqs disabled as a whole. It's sufficient to convert spin_lock operations to their irq saving/restoring versions. As a result, it's now possible to reach the page allocator from the slab allocator without disabling and re-enabling interrupts on the way. Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Diffstat (limited to 'mm')
-rw-r--r--mm/slub.c22
1 files changed, 8 insertions, 14 deletions
diff --git a/mm/slub.c b/mm/slub.c
index b5788040d92e..8433e50d2c8e 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -2010,11 +2010,12 @@ static inline bool pfmemalloc_match(struct page *page, gfp_t gfpflags);
* Try to allocate a partial slab from a specific node.
*/
static void *get_partial_node(struct kmem_cache *s, struct kmem_cache_node *n,
- struct page **ret_page, gfp_t flags)
+ struct page **ret_page, gfp_t gfpflags)
{
struct page *page, *page2;
void *object = NULL;
unsigned int available = 0;
+ unsigned long flags;
int objects;
/*
@@ -2026,11 +2027,11 @@ static void *get_partial_node(struct kmem_cache *s, struct kmem_cache_node *n,
if (!n || !n->nr_partial)
return NULL;
- spin_lock(&n->list_lock);
+ spin_lock_irqsave(&n->list_lock, flags);
list_for_each_entry_safe(page, page2, &n->partial, slab_list) {
void *t;
- if (!pfmemalloc_match(page, flags))
+ if (!pfmemalloc_match(page, gfpflags))
continue;
t = acquire_slab(s, n, page, object == NULL, &objects);
@@ -2051,7 +2052,7 @@ static void *get_partial_node(struct kmem_cache *s, struct kmem_cache_node *n,
break;
}
- spin_unlock(&n->list_lock);
+ spin_unlock_irqrestore(&n->list_lock, flags);
return object;
}
@@ -2779,8 +2780,10 @@ new_slab:
local_irq_restore(flags);
goto reread_page;
}
- if (unlikely(!slub_percpu_partial(c)))
+ if (unlikely(!slub_percpu_partial(c))) {
+ local_irq_restore(flags);
goto new_objects; /* stolen by an IRQ handler */
+ }
page = c->page = slub_percpu_partial(c);
slub_set_percpu_partial(c, page);
@@ -2789,18 +2792,9 @@ new_slab:
goto redo;
}
- local_irq_save(flags);
- if (unlikely(c->page)) {
- local_irq_restore(flags);
- goto reread_page;
- }
-
new_objects:
- lockdep_assert_irqs_disabled();
-
freelist = get_partial(s, gfpflags, node, &page);
- local_irq_restore(flags);
if (freelist)
goto check_new_page;