2019-10-18 05:08:30

by Fengguang Wu

Subject: [PATCH] mm: trivial mark_page_accessed() cleanup

This avoids duplicated PageReferenced() calls.
No behavior change.

Signed-off-by: Fengguang Wu <[email protected]>
---
mm/swap.c | 14 +++++++++-----
1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/mm/swap.c b/mm/swap.c
index 38a52b9..c55720c 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -373,9 +373,15 @@ void mark_page_accessed(struct page *page)
page = compound_head(page);
inc_node_page_state(page, NR_ACCESSED);

- if (!PageActive(page) && !PageUnevictable(page) &&
- PageReferenced(page)) {
-
+ if (!PageReferenced(page)) {
+ SetPageReferenced(page);
+ } else if (PageUnevictable(page)) {
+ /*
+ * Unevictable pages are on the "LRU_UNEVICTABLE" list. But,
+ * this list is never rotated or maintained, so marking an
+ * evictable page accessed has no effect.
+ */
+ } else if (!PageActive(page)) {
/*
* If the page is on the LRU, queue it for activation via
* activate_page_pvecs. Otherwise, assume the page is on a
@@ -389,8 +395,6 @@ void mark_page_accessed(struct page *page)
ClearPageReferenced(page);
if (page_is_file_cache(page))
workingset_activation(page);
- } else if (!PageReferenced(page)) {
- SetPageReferenced(page);
}
if (page_is_idle(page))
clear_page_idle(page);
--
2.7.4

2019-10-22 13:30:38

by Vlastimil Babka

Subject: Re: [PATCH] mm: trivial mark_page_accessed() cleanup

On 10/17/19 12:53 AM, Fengguang Wu wrote:
> This avoids duplicated PageReferenced() calls.
> No behavior change.
>
> Signed-off-by: Fengguang Wu <[email protected]>

Acked-by: Vlastimil Babka <[email protected]>

> ---
> mm/swap.c | 14 +++++++++-----
> 1 file changed, 9 insertions(+), 5 deletions(-)
>
> diff --git a/mm/swap.c b/mm/swap.c
> index 38a52b9..c55720c 100644
> --- a/mm/swap.c
> +++ b/mm/swap.c
> @@ -373,9 +373,15 @@ void mark_page_accessed(struct page *page)
> page = compound_head(page);
> inc_node_page_state(page, NR_ACCESSED);
>
> - if (!PageActive(page) && !PageUnevictable(page) &&
> - PageReferenced(page)) {
> -
> + if (!PageReferenced(page)) {
> + SetPageReferenced(page);
> + } else if (PageUnevictable(page)) {
> + /*
> + * Unevictable pages are on the "LRU_UNEVICTABLE" list. But,
> + * this list is never rotated or maintained, so marking an
> + * evictable page accessed has no effect.
> + */
> + } else if (!PageActive(page)) {
> /*
> * If the page is on the LRU, queue it for activation via
> * activate_page_pvecs. Otherwise, assume the page is on a
> @@ -389,8 +395,6 @@ void mark_page_accessed(struct page *page)
> ClearPageReferenced(page);
> if (page_is_file_cache(page))
> workingset_activation(page);
> - } else if (!PageReferenced(page)) {
> - SetPageReferenced(page);
> }
> if (page_is_idle(page))
> clear_page_idle(page);
>