From: Yisheng Xie <xieyisheng1@xxxxxxxxxx> Subject: 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@xxxxxxxxxx Signed-off-by: Yisheng Xie <xieyisheng1@xxxxxxxxxx> Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@xxxxxxxxx> Acked-by: Minchan Kim <minchan@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/zsmalloc.c | 6 +----- 1 file changed, 1 insertion(+), 5 deletions(-) diff -puN mm/zsmalloc.c~mm-zsmalloc-remove-redundant-setpageprivate2-in-create_page_chain mm/zsmalloc.c --- a/mm/zsmalloc.c~mm-zsmalloc-remove-redundant-setpageprivate2-in-create_page_chain +++ a/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 siz * 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 siz } else { prev_page->freelist = page; } - if (i == nr_pages - 1) - SetPagePrivate2(page); prev_page = page; } } _ -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
