linux-kernel - [PATCH] mm/memory.c: Introduce non-atomic _

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Date:   Mon, 19 Oct 2020 18:15:20 +0800
From:   Muchun Song <songmuchun@...edance.com>
To:     akpm@...ux-foundation.org, sfr@...b.auug.org.au, osalvador@...e.de,
        alexander.h.duyck@...ux.intel.com, mhocko@...e.com,
        yang.shi@...ux.alibaba.com, david@...hat.com, hannes@...xchg.org,
        hughd@...gle.com
Cc:     linux-kernel@...r.kernel.org, linux-mm@...ck.org,
        Muchun Song <songmuchun@...edance.com>
Subject: [PATCH] mm/memory.c: Introduce non-atomic __{Set,Clear}PageSwapCache

For the exclusive reference page, the non-atomic operations is enough,
so replace them to non-atomic operations.

Signed-off-by: Muchun Song <songmuchun@...edance.com>
---
 include/linux/page-flags.h | 2 ++
 mm/memory.c                | 4 ++--
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index fbbb841a9346..ec039dde5e4b 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -401,6 +401,8 @@ static __always_inline int PageSwapCache(struct page *page)
 }
 SETPAGEFLAG(SwapCache, swapcache, PF_NO_TAIL)
 CLEARPAGEFLAG(SwapCache, swapcache, PF_NO_TAIL)
+__SETPAGEFLAG(SwapCache, swapcache, PF_NO_TAIL)
+__CLEARPAGEFLAG(SwapCache, swapcache, PF_NO_TAIL)
 #else
 PAGEFLAG_FALSE(SwapCache)
 #endif
diff --git a/mm/memory.c b/mm/memory.c
index 2d267ef6621a..02dd62da26e0 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3128,10 +3128,10 @@ vm_fault_t do_swap_page(struct vm_fault *vmf)
 				set_page_private(page, entry.val);
 
 				/* Tell memcg to use swap ownership records */
-				SetPageSwapCache(page);
+				__SetPageSwapCache(page);
 				err = mem_cgroup_charge(page, vma->vm_mm,
 							GFP_KERNEL);
-				ClearPageSwapCache(page);
+				__ClearPageSwapCache(page);
 				if (err) {
 					ret = VM_FAULT_OOM;
 					goto out_page;
-- 
2.20.1