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| author | Deyan Wang <wonder_rock@126.com> | 2022-12-01 21:50:45 +0800 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2022-12-11 18:12:17 -0800 |
| commit | ac4b2901a112e4dcee1455c96d89ef83cc7aa545 (patch) | |
| tree | ae3fe734e69c69bb95bac4dbac2d361a31462be4 | |
| parent | 480017957d6380d3336a8e80ad90f70415bb86f7 (diff) | |
| download | linux-ac4b2901a112e4dcee1455c96d89ef83cc7aa545.tar.bz2 | |
mm/page_alloc: update comments in __free_pages_ok()
Add a comment to explain why we call get_pfnblock_migratetype() twice in
__free_pages_ok().
Link: https://lkml.kernel.org/r/20221201135045.31663-1-wonder_rock@126.com
Signed-off-by: Deyan Wang <wonder_rock@126.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| -rw-r--r-- | mm/page_alloc.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 5ab9dd29ef7e..0745aedebb37 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1702,6 +1702,11 @@ static void __free_pages_ok(struct page *page, unsigned int order, if (!free_pages_prepare(page, order, true, fpi_flags)) return; + /* + * Calling get_pfnblock_migratetype() without spin_lock_irqsave() here + * is used to avoid calling get_pfnblock_migratetype() under the lock. + * This will reduce the lock holding time. + */ migratetype = get_pfnblock_migratetype(page, pfn); spin_lock_irqsave(&zone->lock, flags); |