[PATCH v9 03/20] mm/page_idle: no unlikely double check for idle page counting

Alex Shi
2020-03-02T11:00:13Z

As func comments mentioned, few isolated page missing be tolerated.
So why not do further to drop the unlikely double check. That won't
cause more idle pages, but reduce a lock contention.

This is also a preparation for later new page isolation feature.

Signed-off-by: Alex Shi <alex.shi-KPsoFbNs7GizrGE5bRqYAgC/G2K4zDHf@public.gmane.org>
Cc: Andrew Morton <akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>
Cc: Johannes Weiner <hannes-druUgvl0LCNAfugRpC6u6w@public.gmane.org>
Cc: Matthew Wilcox <willy-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>
Cc: Hugh Dickins <hughd-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
Cc: linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org
Cc: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
---
mm/page_idle.c | 8 --------
1 file changed, 8 deletions(-)

diff --git a/mm/page_idle.c b/mm/page_idle.c
index 295512465065..914df63948b1 100644
--- a/mm/page_idle.c
+++ b/mm/page_idle.c
@@ -31,7 +31,6 @@
static struct page *page_idle_get_page(unsigned long pfn)
{
struct page *page;
- pg_data_t *pgdat;

if (!pfn_valid(pfn))
return NULL;
@@ -41,13 +40,6 @@ static struct page *page_idle_get_page(unsigned long pfn)
!get_page_unless_zero(page))
return NULL;

- pgdat = page_pgdat(page);
- spin_lock_irq(&pgdat->lru_lock);
- if (unlikely(!PageLRU(page))) {
- put_page(page);
- page = NULL;
- }
- spin_unlock_irq(&pgdat->lru_lock);
return page;
}

--
1.8.3.1