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mm/mmzone.h: simplify is_highmem_idx() 

There is a lot of historical ifdefery in is_highmem_idx() and its helper
zone_movable_is_highmem() that was required because of two different paths
for nodes and zones initialization that were selected at compile time.

Until commit 3f08a302f5 ("mm: remove CONFIG_HAVE_MEMBLOCK_NODE_MAP
option") the movable_zone variable was only available for configurations
that had CONFIG_HAVE_MEMBLOCK_NODE_MAP enabled so the test in
zone_movable_is_highmem() used that variable only for such configurations.
For other configurations the test checked if the index of ZONE_MOVABLE
was greater by 1 than the index of ZONE_HIGMEM and then movable zone was
considered a highmem zone.  Needless to say, ZONE_MOVABLE - 1 equals
ZONE_HIGHMEM by definition when CONFIG_HIGHMEM=y.

Commit 3f08a302f5 ("mm: remove CONFIG_HAVE_MEMBLOCK_NODE_MAP option")
made movable_zone variable always available.  Since this variable is set
to ZONE_HIGHMEM if CONFIG_HIGHMEM is enabled and highmem zone is
populated, it is enough to check whether

	zone_idx == ZONE_MOVABLE && movable_zone == ZONE_HIGMEM

to test if zone index points to a highmem zone.

Remove zone_movable_is_highmem() that is not used anywhere except
is_highmem_idx() and use the test above in is_highmem_idx() instead.

Link: https://lkml.kernel.org/r/20210426141927.1314326-3-rppt@kernel.org
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Mike Rapoport 2021-06-28 19:41:04 -07:00 committed by Linus Torvalds
parent c5a54c706e
commit b19bd1c976
1 changed files with 1 additions and 12 deletions
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13
include/linux/mmzone.h
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@ -982,22 +982,11 @@ static inline void zone_set_nid(struct zone *zone, int nid) {}
extern int movable_zone;
#ifdef CONFIG_HIGHMEM
static inline int zone_movable_is_highmem(void)
{
#ifdef CONFIG_NEED_MULTIPLE_NODES
return movable_zone == ZONE_HIGHMEM;
#else
return (ZONE_MOVABLE - 1) == ZONE_HIGHMEM;
#endif
}
#endif
static inline int is_highmem_idx(enum zone_type idx)
{
#ifdef CONFIG_HIGHMEM
return (idx == ZONE_HIGHMEM ||
(idx == ZONE_MOVABLE && zone_movable_is_highmem()));
(idx == ZONE_MOVABLE && movable_zone == ZONE_HIGHMEM));
#else
return 0;
#endif