The patch titled
Subject: mm: remove superfluous __ClearPageWaiters()
has been added to the -mm tree. Its filename is
mm-remove-superfluous-__clearpagewaiters.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-remove-superfluous-__clearpagewaiters.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-remove-superfluous-__clearpagewaiters.patch
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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Yu Zhao <yuzhao@xxxxxxxxxx>
Subject: mm: remove superfluous __ClearPageWaiters()
Presumably __ClearPageWaiters() was added to follow the previously removed
__ClearPageActive() pattern.
Only flags that are in PAGE_FLAGS_CHECK_AT_FREE needs to be properly
cleared because otherwise we think there may be some kind of leak.
PG_waiters is not one of those flags and leaving the clearing to
PAGE_FLAGS_CHECK_AT_PREP is more appropriate.
Link: http://lkml.kernel.org/r/20200818184704.3625199-3-yuzhao@xxxxxxxxxx
Signed-off-by: Yu Zhao <yuzhao@xxxxxxxxxx>
Cc: Alexander Duyck <alexander.h.duyck@xxxxxxxxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: Huang Ying <ying.huang@xxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: Nicholas Piggin <npiggin@xxxxxxxxx>
Cc: Qian Cai <cai@xxxxxx>
Cc: Yang Shi <yang.shi@xxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/page-flags.h | 2 +-
mm/filemap.c | 2 ++
mm/memremap.c | 2 --
mm/swap.c | 3 ---
4 files changed, 3 insertions(+), 6 deletions(-)
--- a/include/linux/page-flags.h~mm-remove-superfluous-__clearpagewaiters
+++ a/include/linux/page-flags.h
@@ -318,7 +318,7 @@ static inline int TestClearPage##uname(s
TESTSETFLAG_FALSE(uname) TESTCLEARFLAG_FALSE(uname)
__PAGEFLAG(Locked, locked, PF_NO_TAIL)
-PAGEFLAG(Waiters, waiters, PF_ONLY_HEAD) __CLEARPAGEFLAG(Waiters, waiters, PF_ONLY_HEAD)
+PAGEFLAG(Waiters, waiters, PF_ONLY_HEAD)
PAGEFLAG(Error, error, PF_NO_TAIL) TESTCLEARFLAG(Error, error, PF_NO_TAIL)
PAGEFLAG(Referenced, referenced, PF_HEAD)
TESTCLEARFLAG(Referenced, referenced, PF_HEAD)
--- a/mm/filemap.c~mm-remove-superfluous-__clearpagewaiters
+++ a/mm/filemap.c
@@ -1079,6 +1079,8 @@ static void wake_up_page_bit(struct page
* other pages on it.
*
* That's okay, it's a rare case. The next waker will clear it.
+ * Otherwise the bit will be cleared by PAGE_FLAGS_CHECK_AT_PREP
+ * when the page is being freed.
*/
}
spin_unlock_irqrestore(&q->lock, flags);
--- a/mm/memremap.c~mm-remove-superfluous-__clearpagewaiters
+++ a/mm/memremap.c
@@ -471,8 +471,6 @@ void free_devmap_managed_page(struct pag
return;
}
- __ClearPageWaiters(page);
-
mem_cgroup_uncharge(page);
/*
--- a/mm/swap.c~mm-remove-superfluous-__clearpagewaiters
+++ a/mm/swap.c
@@ -90,7 +90,6 @@ static void __page_cache_release(struct
del_page_from_lru_list(page, lruvec, page_off_lru(page));
spin_unlock_irqrestore(&pgdat->lru_lock, flags);
}
- __ClearPageWaiters(page);
}
static void __put_single_page(struct page *page)
@@ -900,8 +899,6 @@ void release_pages(struct page **pages,
del_page_from_lru_list(page, lruvec, page_off_lru(page));
}
- __ClearPageWaiters(page);
-
list_add(&page->lru, &pages_to_free);
}
if (locked_pgdat)
_
Patches currently in -mm which might be from yuzhao@xxxxxxxxxx are
mm-remove-activate_page-from-unuse_pte.patch
mm-remove-superfluous-__clearpageactive.patch
mm-remove-superfluous-__clearpagewaiters.patch
