[PATCH 09/15] mm/swap: avoid calling swp_swap_info when try to check SWP_STABLE_WRITES

From: Miaohe Lin
Date: Mon May 09 2022 - 09:15:30 EST


Use flags of si directly to check SWP_STABLE_WRITES to avoid possible
READ_ONCE and thus save some cpu cycles.

Signed-off-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>
---
mm/memory.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/memory.c b/mm/memory.c
index 9c3e7e6ac202..89dd15504f3d 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3892,7 +3892,7 @@ vm_fault_t do_swap_page(struct vm_fault *vmf)
*/
exclusive = true;
} else if (exclusive && PageWriteback(page) &&
- (swp_swap_info(entry)->flags & SWP_STABLE_WRITES)) {
+ (si->flags & SWP_STABLE_WRITES)) {
/*
* This is tricky: not all swap backends support
* concurrent page modifications while under writeback.
--
2.23.0