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authorMiaohe Lin <linmiaohe@huawei.com>2021-02-25 17:18:03 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2021-02-26 09:41:01 -0800
commitb7e188ec98b1644ff70a6d3624ea16aadc39f5e0 (patch)
tree9748f1bbea91d5de3e7bfd83c3788e9dcca786f5
parent90aaca852ca13a6c962b25964fb6678120f266b1 (diff)
downloadlinux-b7e188ec98b1644ff70a6d3624ea16aadc39f5e0.tar.bz2
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@huawei.com Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/rmap.c11
1 files changed, 3 insertions, 8 deletions
diff --git a/mm/rmap.c b/mm/rmap.c
index c3f6e060d73f..b49e85605f8f 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1736,9 +1736,9 @@ static bool invalid_migration_vma(struct vm_area_struct *vma, void *arg)
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, enum ttu_flags flags)
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, enum ttu_flags flags)
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