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authorMel Gorman <mgorman@techsingularity.net>2023-01-13 14:12:16 +0300
committerAndrew Morton <akpm@linux-foundation.org>2023-02-03 09:33:12 +0300
commit1ebbb21811b76c3b932959787f37985af36f62fa (patch)
treea5bd6d1d349adfdaeb1f3a713d315123f26ba42c /mm/internal.h
parentab3508854353793cd35e348fde89a5c09b2fd8b5 (diff)
downloadlinux-1ebbb21811b76c3b932959787f37985af36f62fa.tar.xz
mm/page_alloc: explicitly define how __GFP_HIGH non-blocking allocations accesses reserves
GFP_ATOMIC allocations get flagged ALLOC_HARDER which is a vague description. In preparation for the removal of GFP_ATOMIC redefine __GFP_ATOMIC to simply mean non-blocking and renaming ALLOC_HARDER to ALLOC_NON_BLOCK accordingly. __GFP_HIGH is required for access to reserves but non-blocking is granted more access. For example, GFP_NOWAIT is non-blocking but has no special access to reserves. A __GFP_NOFAIL blocking allocation is granted access similar to __GFP_HIGH if the only alternative is an OOM kill. Link: https://lkml.kernel.org/r/20230113111217.14134-6-mgorman@techsingularity.net Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: NeilBrown <neilb@suse.de> Cc: Thierry Reding <thierry.reding@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/internal.h')
-rw-r--r--mm/internal.h7
1 files changed, 5 insertions, 2 deletions
diff --git a/mm/internal.h b/mm/internal.h
index f7c3bc80c475..b0b88a95347f 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -778,7 +778,10 @@ unsigned int reclaim_clean_pages_from_list(struct zone *zone,
#define ALLOC_OOM ALLOC_NO_WATERMARKS
#endif
-#define ALLOC_HARDER 0x10 /* try to alloc harder */
+#define ALLOC_NON_BLOCK 0x10 /* Caller cannot block. Allow access
+ * to 25% of the min watermark or
+ * 62.5% if __GFP_HIGH is set.
+ */
#define ALLOC_MIN_RESERVE 0x20 /* __GFP_HIGH set. Allow access to 50%
* of the min watermark.
*/
@@ -793,7 +796,7 @@ unsigned int reclaim_clean_pages_from_list(struct zone *zone,
#define ALLOC_KSWAPD 0x800 /* allow waking of kswapd, __GFP_KSWAPD_RECLAIM set */
/* Flags that allow allocations below the min watermark. */
-#define ALLOC_RESERVES (ALLOC_HARDER|ALLOC_MIN_RESERVE|ALLOC_HIGHATOMIC|ALLOC_OOM)
+#define ALLOC_RESERVES (ALLOC_NON_BLOCK|ALLOC_MIN_RESERVE|ALLOC_HIGHATOMIC|ALLOC_OOM)
enum ttu_flags;
struct tlbflush_unmap_batch;