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authorHyeonggon Yoo <42.hyeyoo@gmail.com>2022-10-15 13:34:29 +0900
committerVlastimil Babka <vbabka@suse.cz>2022-10-15 21:42:05 +0200
commite36ce448a08d43de69e7449eb225805a7a8addf8 (patch)
treed1b0f706f04ff2bb76f86cba4597c7e3f41a86d7 /mm
parentd5eff736902d5565a24f1b571b5987b3e5ee9a5b (diff)
mm/slab: use kmalloc_node() for off slab freelist_idx_t array allocation
After commit d6a71648dbc0 ("mm/slab: kmalloc: pass requests larger than order-1 page to page allocator"), SLAB passes large ( > PAGE_SIZE * 2) requests to buddy like SLUB does. SLAB has been using kmalloc caches to allocate freelist_idx_t array for off slab caches. But after the commit, freelist_size can be bigger than KMALLOC_MAX_CACHE_SIZE. Instead of using pointer to kmalloc cache, use kmalloc_node() and only check if the kmalloc cache is off slab during calculate_slab_order(). If freelist_size > KMALLOC_MAX_CACHE_SIZE, no looping condition happens as it allocates freelist_idx_t array directly from buddy. Link: https://lore.kernel.org/all/20221014205818.GA1428667@roeck-us.net/ Reported-and-tested-by: Guenter Roeck <linux@roeck-us.net> Fixes: d6a71648dbc0 ("mm/slab: kmalloc: pass requests larger than order-1 page to page allocator") Signed-off-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Diffstat (limited to 'mm')
-rw-r--r--mm/slab.c37
1 files changed, 19 insertions, 18 deletions
diff --git a/mm/slab.c b/mm/slab.c
index a5486ff8362a..d1f6e2c64c2e 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -1619,7 +1619,7 @@ static void slab_destroy(struct kmem_cache *cachep, struct slab *slab)
* although actual page can be freed in rcu context
*/
if (OFF_SLAB(cachep))
- kmem_cache_free(cachep->freelist_cache, freelist);
+ kfree(freelist);
}
/*
@@ -1671,21 +1671,27 @@ static size_t calculate_slab_order(struct kmem_cache *cachep,
if (flags & CFLGS_OFF_SLAB) {
struct kmem_cache *freelist_cache;
size_t freelist_size;
+ size_t freelist_cache_size;
freelist_size = num * sizeof(freelist_idx_t);
- freelist_cache = kmalloc_slab(freelist_size, 0u);
- if (!freelist_cache)
- continue;
-
- /*
- * Needed to avoid possible looping condition
- * in cache_grow_begin()
- */
- if (OFF_SLAB(freelist_cache))
- continue;
+ if (freelist_size > KMALLOC_MAX_CACHE_SIZE) {
+ freelist_cache_size = PAGE_SIZE << get_order(freelist_size);
+ } else {
+ freelist_cache = kmalloc_slab(freelist_size, 0u);
+ if (!freelist_cache)
+ continue;
+ freelist_cache_size = freelist_cache->size;
+
+ /*
+ * Needed to avoid possible looping condition
+ * in cache_grow_begin()
+ */
+ if (OFF_SLAB(freelist_cache))
+ continue;
+ }
/* check if off slab has enough benefit */
- if (freelist_cache->size > cachep->size / 2)
+ if (freelist_cache_size > cachep->size / 2)
continue;
}
@@ -2061,11 +2067,6 @@ done:
cachep->flags &= ~(SLAB_RED_ZONE | SLAB_STORE_USER);
#endif
- if (OFF_SLAB(cachep)) {
- cachep->freelist_cache =
- kmalloc_slab(cachep->freelist_size, 0u);
- }
-
err = setup_cpu_cache(cachep, gfp);
if (err) {
__kmem_cache_release(cachep);
@@ -2292,7 +2293,7 @@ static void *alloc_slabmgmt(struct kmem_cache *cachep,
freelist = NULL;
else if (OFF_SLAB(cachep)) {
/* Slab management obj is off-slab. */
- freelist = kmem_cache_alloc_node(cachep->freelist_cache,
+ freelist = kmalloc_node(cachep->freelist_size,
local_flags, nodeid);
} else {
/* We will use last bytes at the slab for freelist */