lkml.org 
[lkml]   [2021]   [Jan]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH] mm/rmap: use page_not_mapped in try_to_unmap()
Date
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.

Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
---
mm/rmap.c | 11 +++--------
1 file 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
--
2.19.1
\
 
 \ /
  Last update: 2021-01-30 10:18    [W:0.019 / U:0.872 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site