From: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Currently, cache_grow() assumes that allocated page's nodeid would be
same with parameter nodeid which is used for allocation request. If
we discard this assumption, we can handle fallback_alloc() case
gracefully. So, this patch makes cache_grow() handle the page allocated
on arbitrary node and clean-up relevant code.
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
---
mm/slab.c | 60 +++++++++++++++++++++---------------------------------------
1 file changed, 21 insertions(+), 39 deletions(-)
diff --git a/mm/slab.c b/mm/slab.c
index 52fc5e3..ce8ed65 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -2518,13 +2518,14 @@ static void slab_map_pages(struct kmem_cache *cache, struct page *page,
* Grow (by 1) the number of slabs within a cache. This is called by
* kmem_cache_alloc() when there are no active objs left in a cache.
*/
-static int cache_grow(struct kmem_cache *cachep,
- gfp_t flags, int nodeid, struct page *page)
+static int cache_grow(struct kmem_cache *cachep, gfp_t flags, int nodeid)
{
void *freelist;
size_t offset;
gfp_t local_flags;
+ int page_node;
struct kmem_cache_node *n;
+ struct page *page;
/*
* Be lazy and only check for valid flags here, keeping it out of the
@@ -2552,12 +2553,12 @@ static int cache_grow(struct kmem_cache *cachep,
* Get mem for the objs. Attempt to allocate a physical page from
* 'nodeid'.
*/
- if (!page)
- page = kmem_getpages(cachep, local_flags, nodeid);
+ page = kmem_getpages(cachep, local_flags, nodeid);
if (!page)
goto failed;
- n = get_node(cachep, nodeid);
+ page_node = page_to_nid(page);
+ n = get_node(cachep, page_node);
/* Get colour for the slab, and cal the next value. */
n->colour_next++;
@@ -2572,7 +2573,7 @@ static int cache_grow(struct kmem_cache *cachep,
/* Get slab management. */
freelist = alloc_slabmgmt(cachep, page, offset,
- local_flags & ~GFP_CONSTRAINT_MASK, nodeid);
+ local_flags & ~GFP_CONSTRAINT_MASK, page_node);
if (OFF_SLAB(cachep) && !freelist)
goto opps1;
@@ -2591,13 +2592,13 @@ static int cache_grow(struct kmem_cache *cachep,
STATS_INC_GROWN(cachep);
n->free_objects += cachep->num;
spin_unlock(&n->list_lock);
- return 1;
+ return page_node;
opps1:
kmem_freepages(cachep, page);
failed:
if (gfpflags_allow_blocking(local_flags))
local_irq_disable();
- return 0;
+ return -1;
}
#if DEBUG
@@ -2878,14 +2879,14 @@ alloc_done:
return obj;
}
- x = cache_grow(cachep, gfp_exact_node(flags), node, NULL);
+ x = cache_grow(cachep, gfp_exact_node(flags), node);
/* cache_grow can reenable interrupts, then ac could change. */
ac = cpu_cache_get(cachep);
node = numa_mem_id();
/* no objects in sight? abort */
- if (!x && ac->avail == 0)
+ if (x < 0 && ac->avail == 0)
return NULL;
if (!ac->avail) /* objects refilled by interrupt? */
@@ -3014,7 +3015,6 @@ static void *alternate_node_alloc(struct kmem_cache *cachep, gfp_t flags)
static void *fallback_alloc(struct kmem_cache *cache, gfp_t flags)
{
struct zonelist *zonelist;
- gfp_t local_flags;
struct zoneref *z;
struct zone *zone;
enum zone_type high_zoneidx = gfp_zone(flags);
@@ -3025,8 +3025,6 @@ static void *fallback_alloc(struct kmem_cache *cache, gfp_t flags)
if (flags & __GFP_THISNODE)
return NULL;
- local_flags = flags & (GFP_CONSTRAINT_MASK|GFP_RECLAIM_MASK);
-
retry_cpuset:
cpuset_mems_cookie = read_mems_allowed_begin();
zonelist = node_zonelist(mempolicy_slab_node(), flags);
@@ -3056,33 +3054,17 @@ retry:
* We may trigger various forms of reclaim on the allowed
* set and go into memory reserves if necessary.
*/
- struct page *page;
+ nid = cache_grow(cache, flags, numa_mem_id());
+ if (nid >= 0) {
+ obj = ____cache_alloc_node(cache,
+ gfp_exact_node(flags), nid);
- if (gfpflags_allow_blocking(local_flags))
- local_irq_enable();
- kmem_flagcheck(cache, flags);
- page = kmem_getpages(cache, local_flags, numa_mem_id());
- if (gfpflags_allow_blocking(local_flags))
- local_irq_disable();
- if (page) {
/*
- * Insert into the appropriate per node queues
+ * Another processor may allocate the objects in
+ * the slab since we are not holding any locks.
*/
- nid = page_to_nid(page);
- if (cache_grow(cache, flags, nid, page)) {
- obj = ____cache_alloc_node(cache,
- gfp_exact_node(flags), nid);
- if (!obj)
- /*
- * Another processor may allocate the
- * objects in the slab since we are
- * not holding any locks.
- */
- goto retry;
- } else {
- /* cache_grow already freed obj */
- obj = NULL;
- }
+ if (!obj)
+ goto retry;
}
}
@@ -3133,8 +3115,8 @@ retry:
must_grow:
spin_unlock(&n->list_lock);
- x = cache_grow(cachep, gfp_exact_node(flags), nodeid, NULL);
- if (x)
+ x = cache_grow(cachep, gfp_exact_node(flags), nodeid);
+ if (x >= 0)
goto retry;
return fallback_alloc(cachep, flags);
--
1.9.1
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