diff options
| author | Muchun Song <songmuchun@bytedance.com> | 2020-12-14 19:11:25 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-12-15 12:13:44 -0800 |
| commit | 7ad69832f37e3cea8557db6df7c793905f1135e8 (patch) | |
| tree | 36dac0da78a06ce7f6e09841a25db68ed14a893a /mm/page_alloc.c | |
| parent | 470c61d70299b1826f56ff5fede10786798e3c14 (diff) | |
| download | linux-7ad69832f37e3cea8557db6df7c793905f1135e8.tar.bz2 | |
mm/page_alloc: speed up the iteration of max_order
When we free a page whose order is very close to MAX_ORDER and greater
than pageblock_order, it wastes some CPU cycles to increase max_order to
MAX_ORDER one by one and check the pageblock migratetype of that page
repeatedly especially when MAX_ORDER is much larger than pageblock_order.
We also should not be checking migratetype of buddy when "order ==
MAX_ORDER - 1" as the buddy pfn may be invalid, so adjust the condition.
With the new check, we don't need the max_order check anymore, so we
replace it.
Also adjust max_order initialization so that it's lower by one than
previously, which makes the code hopefully more clear.
Link: https://lkml.kernel.org/r/20201204155109.55451-1-songmuchun@bytedance.com
Fixes: d9dddbf55667 ("mm/page_alloc: prevent merging between isolated and other pageblocks")
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/page_alloc.c')
| -rw-r--r-- | mm/page_alloc.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c index c026908b5306..70c7cb5cc68c 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -996,7 +996,7 @@ static inline void __free_one_page(struct page *page, struct page *buddy; bool to_tail; - max_order = min_t(unsigned int, MAX_ORDER, pageblock_order + 1); + max_order = min_t(unsigned int, MAX_ORDER - 1, pageblock_order); VM_BUG_ON(!zone_is_initialized(zone)); VM_BUG_ON_PAGE(page->flags & PAGE_FLAGS_CHECK_AT_PREP, page); @@ -1009,7 +1009,7 @@ static inline void __free_one_page(struct page *page, VM_BUG_ON_PAGE(bad_range(zone, page), page); continue_merging: - while (order < max_order - 1) { + while (order < max_order) { if (compaction_capture(capc, page, order, migratetype)) { __mod_zone_freepage_state(zone, -(1 << order), migratetype); @@ -1035,7 +1035,7 @@ continue_merging: pfn = combined_pfn; order++; } - if (max_order < MAX_ORDER) { + if (order < MAX_ORDER - 1) { /* If we are here, it means order is >= pageblock_order. * We want to prevent merge between freepages on isolate * pageblock and normal pageblock. Without this, pageblock @@ -1056,7 +1056,7 @@ continue_merging: is_migrate_isolate(buddy_mt))) goto done_merging; } - max_order++; + max_order = order + 1; goto continue_merging; } |