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mm: page_alloc: simplify pageblock migratetype check in __free_one_page() 

Move pageblock migratetype check code in the while loop to simplify the
logic. It also saves redundant buddy page checking code.

Link: https://lkml.kernel.org/r/20220401230804.1658207-1-zi.yan@sent.com
Link: https://lore.kernel.org/linux-mm/27ff69f9-60c5-9e59-feb2-295250077551@suse.cz/
Signed-off-by: Zi Yan <ziy@nvidia.com>
Suggested-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Zi Yan 2022-04-28 23:16:01 -07:00 committed by akpm
parent 379313241e
commit bb0e28eb5b
1 changed files with 17 additions and 29 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

46
mm/page_alloc.c
View File

@ -1053,7 +1053,6 @@ static inline void __free_one_page(struct page *page,
int migratetype, fpi_t fpi_flags)
{
struct capture_control *capc = task_capc(zone);
unsigned int max_order = pageblock_order;
unsigned long buddy_pfn;
unsigned long combined_pfn;
struct page *buddy;
@ -1069,8 +1068,7 @@ static inline void __free_one_page(struct page *page,
VM_BUG_ON_PAGE(pfn & ((1 << order) - 1), page);
VM_BUG_ON_PAGE(bad_range(zone, page), page);
continue_merging:
while (order < max_order) {
while (order < MAX_ORDER - 1) {
if (compaction_capture(capc, page, order, migratetype)) {
__mod_zone_freepage_state(zone, -(1 << order),
migratetype);
@ -1081,6 +1079,22 @@ continue_merging:
if (!page_is_buddy(page, buddy, order))
goto done_merging;
if (unlikely(order >= pageblock_order)) {
/*
* We want to prevent merge between freepages on pageblock
* without fallbacks and normal pageblock. Without this,
* pageblock isolation could cause incorrect freepage or CMA
* accounting or HIGHATOMIC accounting.
*/
int buddy_mt = get_pageblock_migratetype(buddy);
if (migratetype != buddy_mt
&& (!migratetype_is_mergeable(migratetype) ||
!migratetype_is_mergeable(buddy_mt)))
goto done_merging;
}
/*
* Our buddy is free or it is CONFIG_DEBUG_PAGEALLOC guard page,
* merge with it and move up one order.
@ -1094,32 +1108,6 @@ continue_merging:
pfn = combined_pfn;
order++;
}
if (order < MAX_ORDER - 1) {
/* If we are here, it means order is >= pageblock_order.
* We want to prevent merge between freepages on pageblock
* without fallbacks and normal pageblock. Without this,
* pageblock isolation could cause incorrect freepage or CMA
* accounting or HIGHATOMIC accounting.
*
* We don't want to hit this code for the more frequent
* low-order merging.
*/
int buddy_mt;
buddy_pfn = __find_buddy_pfn(pfn, order);
buddy = page + (buddy_pfn - pfn);
if (!page_is_buddy(page, buddy, order))
goto done_merging;
buddy_mt = get_pageblock_migratetype(buddy);
if (migratetype != buddy_mt
&& (!migratetype_is_mergeable(migratetype) ||
!migratetype_is_mergeable(buddy_mt)))
goto done_merging;
max_order = order + 1;
goto continue_merging;
}
done_merging:
set_buddy_order(page, order);