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-rw-r--r--mm/slub.c21
1 files changed, 19 insertions, 2 deletions
diff --git a/mm/slub.c b/mm/slub.c
index a5832f8..03ae549 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -205,6 +205,11 @@ static inline void ClearSlabDebug(struct page *page)
#define ARCH_SLAB_MINALIGN __alignof__(unsigned long long)
#endif
+/*
+ * The page->inuse field is 16 bit thus we have this limitation
+ */
+#define MAX_OBJECTS_PER_SLAB 65535
+
/* Internal SLUB flags */
#define __OBJECT_POISON 0x80000000 /* Poison object */
@@ -1736,8 +1741,17 @@ static inline int slab_order(int size, int min_objects,
{
int order;
int rem;
+ int min_order = slub_min_order;
- for (order = max(slub_min_order,
+ /*
+ * If we would create too many object per slab then reduce
+ * the slab order even if it goes below slub_min_order.
+ */
+ while (min_order > 0 &&
+ (PAGE_SIZE << min_order) >= MAX_OBJECTS_PER_SLAB * size)
+ min_order--;
+
+ for (order = max(min_order,
fls(min_objects * size - 1) - PAGE_SHIFT);
order <= max_order; order++) {
@@ -1751,6 +1765,9 @@ static inline int slab_order(int size, int min_objects,
if (rem <= slab_size / fract_leftover)
break;
+ /* If the next size is too high then exit now */
+ if (slab_size * 2 >= MAX_OBJECTS_PER_SLAB * size)
+ break;
}
return order;
@@ -2037,7 +2054,7 @@ static int calculate_sizes(struct kmem_cache *s)
* The page->inuse field is only 16 bit wide! So we cannot have
* more than 64k objects per slab.
*/
- if (!s->objects || s->objects > 65535)
+ if (!s->objects || s->objects > MAX_OBJECTS_PER_SLAB)
return 0;
return 1;
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