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Commit cc965a29 authored by Michal Hocko's avatar Michal Hocko Committed by Linus Torvalds
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mm: kvmalloc support __GFP_RETRY_MAYFAIL for all sizes 

Now that __GFP_RETRY_MAYFAIL has a reasonable semantic regardless of the
request size we can drop the hackish implementation for !costly orders.
__GFP_RETRY_MAYFAIL retries as long as the reclaim makes a forward
progress and backs of when we are out of memory for the requested size.
Therefore we do not need to enforce__GFP_NORETRY for !costly orders just
to silent the oom killer anymore.

Link: http://lkml.kernel.org/r/20170623085345.11304-5-mhocko@kernel.org


Signed-off-by: default avatarMichal Hocko <mhocko@suse.com>
Acked-by: default avatarVlastimil Babka <vbabka@suse.cz>
Cc: Alex Belits <alex.belits@cavium.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Darrick J. Wong <darrick.wong@oracle.com>
Cc: David Daney <david.daney@cavium.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: NeilBrown <neilb@suse.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 91c63ecd

mm/util.c

+4 −10
Original line number Diff line number Diff line
@@ -339,9 +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 and __GFP_NOFAIL are not supported. __GFP_RETRY_MAYFAIL

 * 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.

 * Reclaim modifiers - __GFP_NORETRY and __GFP_NOFAIL are not supported.

 * __GFP_RETRY_MAYFAIL is supported, 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.

 */
@@ -366,13 +366,7 @@ void *kvmalloc_node(size_t size, gfp_t flags, int node) 
	if (size > PAGE_SIZE) {

		kmalloc_flags |= __GFP_NOWARN;



		/*

		 * We have to override __GFP_RETRY_MAYFAIL 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_RETRY_MAYFAIL) ||

				(size <= PAGE_SIZE << PAGE_ALLOC_COSTLY_ORDER))

		if (!(kmalloc_flags & __GFP_RETRY_MAYFAIL))

			kmalloc_flags |= __GFP_NORETRY;

	}