From: Miaohe Lin <linmiaohe@xxxxxxxxxx> Subject: mm/rmap: use page_not_mapped in try_to_unmap() page_mapcount_is_zero() calculates accurately how many mappings a hugepage has in order to check against 0 only. This is a waste of cpu time. We can do this via page_not_mapped() to save some possible atomic_read cycles. Remove the function page_mapcount_is_zero() as it's not used anymore and move page_not_mapped() above try_to_unmap() to avoid identifier undeclared compilation error. Link: https://lkml.kernel.org/r/20210130084904.35307-1-linmiaohe@xxxxxxxxxx Signed-off-by: Miaohe Lin <linmiaohe@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/rmap.c | 11 +++-------- 1 file changed, 3 insertions(+), 8 deletions(-) --- a/mm/rmap.c~mm-rmap-use-page_not_mapped-in-try_to_unmap +++ a/mm/rmap.c @@ -1736,9 +1736,9 @@ static bool invalid_migration_vma(struct return vma_is_temporary_stack(vma); } -static int page_mapcount_is_zero(struct page *page) +static int page_not_mapped(struct page *page) { - return !total_mapcount(page); + return !page_mapped(page); } /** @@ -1756,7 +1756,7 @@ bool try_to_unmap(struct page *page, enu struct rmap_walk_control rwc = { .rmap_one = try_to_unmap_one, .arg = (void *)flags, - .done = page_mapcount_is_zero, + .done = page_not_mapped, .anon_lock = page_lock_anon_vma_read, }; @@ -1780,11 +1780,6 @@ bool try_to_unmap(struct page *page, enu return !page_mapcount(page) ? true : false; } -static int page_not_mapped(struct page *page) -{ - return !page_mapped(page); -} - /** * try_to_munlock - try to munlock a page * @page: the page to be munlocked _
