On 10/19/20 10:58 PM, Muchun Song wrote:
On Mon, Oct 19, 2020 at 8:31 PM Michal Hocko <mhocko@xxxxxxxx> wrote:
On Mon 19-10-20 18:15:20, Muchun Song wrote:
For the exclusive reference page, the non-atomic operations is enough,
so replace them to non-atomic operations.
I do expect you do not see any difference in runtime and this is mostly
driven by the code reading, right? Being explicit about this in the code
would be preferred.
Yeah, just code reading.And the set_bit and __set_bit is actually different
on some architectures. Thanks.
No objection to the change.
Signed-off-by: Muchun Song <songmuchun@xxxxxxxxxxxxx>
With an improved changelog
Acked-by: Michal Hocko <mhocko@xxxxxxxx>
---
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);
Good evening, Muchun. I found there are still some places could be
replaced with __SetPageSwapCache（）. Such as shmem_replace_page（）, why
PG_locked has been set before SetPageSwapCache（） is involved.
Would you please to check the rest places? :)
Thanks
Acked-by: Yanfei Xu <yanfei.xu@xxxxxxxxxxxxx>
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
--
Michal Hocko
SUSE Labs
