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authorPingfan Liu <kernelfans@gmail.com>2018-12-28 11:38:43 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2018-12-28 23:11:51 +0300
commit125b860b251ad226b1384b6db06be37485127f69 (patch)
tree412bd27ba3e790e00007e53a2a8cc31f88a82f2b /include
parentfcf9a0ef8dc3a3fb8be9de12b0e006c85ed5dc29 (diff)
downloadlinux-125b860b251ad226b1384b6db06be37485127f69.tar.xz
mm/pageblock: throw compile error if pageblock_bits cannot hold MIGRATE_TYPES
Currently, NR_PAGEBLOCK_BITS and MIGRATE_TYPES are not associated by code. If someone adds extra migrate type, then he may forget to enlarge the NR_PAGEBLOCK_BITS. Hence it requires some way to fix. NR_PAGEBLOCK_BITS depends on MIGRATE_TYPES, while these macro spread on two different .h file with reverse dependency, it is a little hard to refer to MIGRATE_TYPES in pageblock-flag.h. This patch tries to remind such relation in compiling-time. Link: http://lkml.kernel.org/r/1544508709-11358-1-git-send-email-kernelfans@gmail.com Signed-off-by: Pingfan Liu <kernelfans@gmail.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Michal Hocko <mhocko@suse.com> Cc: Pavel Tatashin <pavel.tatashin@microsoft.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Mike Rapoport <rppt@linux.vnet.ibm.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Alexander Duyck <alexander.h.duyck@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include')
-rw-r--r--include/linux/pageblock-flags.h3
1 files changed, 2 insertions, 1 deletions
diff --git a/include/linux/pageblock-flags.h b/include/linux/pageblock-flags.h
index 9132c5cb41f1..06a66327333d 100644
--- a/include/linux/pageblock-flags.h
+++ b/include/linux/pageblock-flags.h
@@ -25,10 +25,11 @@
#include <linux/types.h>
+#define PB_migratetype_bits 3
/* Bit indices that affect a whole block of pages */
enum pageblock_bits {
PB_migrate,
- PB_migrate_end = PB_migrate + 3 - 1,
+ PB_migrate_end = PB_migrate + PB_migratetype_bits - 1,
/* 3 bits required for migrate types */
PB_migrate_skip,/* If set the block is skipped by compaction */