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-rw-r--r--mm/util.c18
1 files changed, 15 insertions, 3 deletions
diff --git a/mm/util.c b/mm/util.c
index 10a14a0ac3c2..f4e590b2c0da 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -339,7 +339,9 @@ EXPORT_SYMBOL(vm_mmap);
* Uses kmalloc to get the memory but if the allocation fails then falls back
* to the vmalloc allocator. Use kvfree for freeing the memory.
*
- * Reclaim modifiers - __GFP_NORETRY, __GFP_REPEAT and __GFP_NOFAIL are not supported
+ * Reclaim modifiers - __GFP_NORETRY and __GFP_NOFAIL are not supported. __GFP_REPEAT
+ * is supported only for large (>32kB) allocations, and it should be used only if
+ * kmalloc is preferable to the vmalloc fallback, due to visible performance drawbacks.
*
* Any use of gfp flags outside of GFP_KERNEL should be consulted with mm people.
*/
@@ -358,8 +360,18 @@ void *kvmalloc_node(size_t size, gfp_t flags, int node)
* Make sure that larger requests are not too disruptive - no OOM
* killer and no allocation failure warnings as we have a fallback
*/
- if (size > PAGE_SIZE)
- kmalloc_flags |= __GFP_NORETRY | __GFP_NOWARN;
+ if (size > PAGE_SIZE) {
+ kmalloc_flags |= __GFP_NOWARN;
+
+ /*
+ * We have to override __GFP_REPEAT by __GFP_NORETRY for !costly
+ * requests because there is no other way to tell the allocator
+ * that we want to fail rather than retry endlessly.
+ */
+ if (!(kmalloc_flags & __GFP_REPEAT) ||
+ (size <= PAGE_SIZE << PAGE_ALLOC_COSTLY_ORDER))
+ kmalloc_flags |= __GFP_NORETRY;
+ }
ret = kmalloc_node(size, kmalloc_flags, node);