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Message-Id: <20210709131647.000597038@linuxfoundation.org>
Date: Fri, 9 Jul 2021 15:20:19 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-kernel@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
stable@...r.kernel.org, Miaohe Lin <linmiaohe@...wei.com>,
Andrew Morton <akpm@...ux-foundation.org>,
Linus Torvalds <torvalds@...ux-foundation.org>,
Sasha Levin <sashal@...nel.org>
Subject: [PATCH 4.19 03/34] mm/rmap: use page_not_mapped in try_to_unmap()
From: Miaohe Lin <linmiaohe@...wei.com>
[ Upstream commit b7e188ec98b1644ff70a6d3624ea16aadc39f5e0 ]
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@...wei.com>
Signed-off-by: Andrew Morton <akpm@...ux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@...ux-foundation.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
mm/rmap.c | 11 +++--------
1 file changed, 3 insertions(+), 8 deletions(-)
diff --git a/mm/rmap.c b/mm/rmap.c
index 69ce68616cbf..70872d5b203c 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1682,9 +1682,9 @@ static bool invalid_migration_vma(struct vm_area_struct *vma, void *arg)
return is_vma_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);
}
/**
@@ -1702,7 +1702,7 @@ 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,
};
@@ -1726,11 +1726,6 @@ 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
--
2.30.2
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