From: Yu Zhao <yuzhao@google.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: "Alexander Duyck" <alexander.h.duyck@linux.intel.com>,
"Huang Ying" <ying.huang@intel.com>,
"David Hildenbrand" <david@redhat.com>,
"Michal Hocko" <mhocko@suse.com>,
"Yang Shi" <yang.shi@linux.alibaba.com>, "Qian Cai" <cai@lca.pw>,
"Mel Gorman" <mgorman@suse.de>,
"Nicholas Piggin" <npiggin@gmail.com>,
"Jérôme Glisse" <jglisse@redhat.com>,
"Hugh Dickins" <hughd@google.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
"Joonsoo Kim" <iamjoonsoo.kim@lge.com>,
"Yu Zhao" <yuzhao@google.com>
Subject: [PATCH v2 3/3] mm: remove superfluous __ClearPageWaiters()
Date: Tue, 18 Aug 2020 12:47:04 -0600 [thread overview]
Message-ID: <20200818184704.3625199-3-yuzhao@google.com> (raw)
In-Reply-To: <20200818184704.3625199-1-yuzhao@google.com>
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.
Signed-off-by: Yu Zhao <yuzhao@google.com>
---
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(-)
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index 6be1aa559b1e..dba80a2bdfba 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -318,7 +318,7 @@ static inline int TestClearPage##uname(struct page *page) { return 0; }
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)
diff --git a/mm/filemap.c b/mm/filemap.c
index 1aaea26556cc..75240c7ef73f 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1079,6 +1079,8 @@ static void wake_up_page_bit(struct page *page, int bit_nr)
* 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);
diff --git a/mm/memremap.c b/mm/memremap.c
index 3a06eb91cb59..a9d02ffaf9e3 100644
--- a/mm/memremap.c
+++ b/mm/memremap.c
@@ -451,8 +451,6 @@ void free_devmap_managed_page(struct page *page)
return;
}
- __ClearPageWaiters(page);
-
mem_cgroup_uncharge(page);
/*
diff --git a/mm/swap.c b/mm/swap.c
index 999a84dbe12c..40bf20a75278 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -90,7 +90,6 @@ static void __page_cache_release(struct page *page)
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, int nr)
del_page_from_lru_list(page, lruvec, page_off_lru(page));
}
- __ClearPageWaiters(page);
-
list_add(&page->lru, &pages_to_free);
}
if (locked_pgdat)
--
2.28.0.220.ged08abb693-goog
next prev parent reply other threads:[~2020-08-18 18:47 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-18 18:47 [PATCH v2 1/3] mm: remove activate_page() from unuse_pte() Yu Zhao
2020-08-18 18:47 ` [PATCH v2 2/3] mm: remove superfluous __ClearPageActive() Yu Zhao
2020-08-19 23:04 ` Yang Shi
2020-08-18 18:47 ` Yu Zhao [this message]
2020-08-19 23:06 ` [PATCH v2 3/3] mm: remove superfluous __ClearPageWaiters() Yang Shi
2020-08-19 23:39 ` Yu Zhao
2020-08-20 0:16 ` Yang Shi
2020-08-20 6:18 ` Michal Hocko
2020-08-20 8:12 ` Yu Zhao
2020-08-19 22:16 ` [PATCH v2 1/3] mm: remove activate_page() from unuse_pte() Yang Shi
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