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authorYisheng Xie <xieyisheng1@huawei.com>2017-02-24 14:59:42 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2017-02-24 17:46:56 -0800
commit22c5cef16278bf83aa54ac96a7735ce82f93524e (patch)
tree2be9e81101c4a3370addbfcf2b3694ac1f34a49b
parente1587a4945408faa58d0485002c110eb2454740c (diff)
mm/zsmalloc: remove redundant SetPagePrivate2 in create_page_chain
We had used page->lru to link the component pages (except the first page) of a zspage, and used INIT_LIST_HEAD(&page->lru) to init it. Therefore, to get the last page's next page, which is NULL, we had to use page flag PG_Private_2 to identify it. But now, we use page->freelist to link all of the pages in zspage and init the page->freelist as NULL for last page, so no need to use PG_Private_2 anymore. This remove redundant SetPagePrivate2 in create_page_chain and ClearPagePrivate2 in reset_page(). Save a few cycles for migration of zsmalloc page :) Link: http://lkml.kernel.org/r/1487076509-49270-1-git-send-email-xieyisheng1@huawei.com Signed-off-by: Yisheng Xie <xieyisheng1@huawei.com> Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Acked-by: Minchan Kim <minchan@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/zsmalloc.c6
1 files changed, 1 insertions, 5 deletions
diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
index a1f24989ac23..25d0fb6443d1 100644
--- a/mm/zsmalloc.c
+++ b/mm/zsmalloc.c
@@ -24,7 +24,6 @@
*
* Usage of struct page flags:
* PG_private: identifies the first component page
- * PG_private2: identifies the last component page
* PG_owner_priv_1: identifies the huge component page
*
*/
@@ -938,7 +937,6 @@ static void reset_page(struct page *page)
{
__ClearPageMovable(page);
ClearPagePrivate(page);
- ClearPagePrivate2(page);
set_page_private(page, 0);
page_mapcount_reset(page);
ClearPageHugeObject(page);
@@ -1085,7 +1083,7 @@ static void create_page_chain(struct size_class *class, struct zspage *zspage,
* 2. each sub-page point to zspage using page->private
*
* we set PG_private to identify the first page (i.e. no other sub-page
- * has this flag set) and PG_private_2 to identify the last page.
+ * has this flag set).
*/
for (i = 0; i < nr_pages; i++) {
page = pages[i];
@@ -1100,8 +1098,6 @@ static void create_page_chain(struct size_class *class, struct zspage *zspage,
} else {
prev_page->freelist = page;
}
- if (i == nr_pages - 1)
- SetPagePrivate2(page);
prev_page = page;
}
}