From: Matthew Wilcox <willy@infradead.org>
To: linux-mm@kvack.org, linux-fsdevel@vger.kernel.org
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>,
Will Deacon <will.deacon@arm.com>
Subject: [PATCH 1/2] mm: Remove definition of clear_bit_unlock_is_negative_byte
Date: Thu, 26 Mar 2020 05:24:28 -0700 [thread overview]
Message-ID: <20200326122429.20710-2-willy@infradead.org> (raw)
In-Reply-To: <20200326122429.20710-1-willy@infradead.org>
From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
This local definition hasn't been used since commit 84c6591103db
("locking/atomics, asm-generic/bitops/lock.h: Rewrite using
atomic_fetch_*()") which provided a default definition.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Will Deacon <will.deacon@arm.com>
---
mm/filemap.c | 23 -----------------------
1 file changed, 23 deletions(-)
diff --git a/mm/filemap.c b/mm/filemap.c
index 80f7e1ae744c..312afbfcb49a 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1248,29 +1248,6 @@ void add_page_wait_queue(struct page *page, wait_queue_entry_t *waiter)
}
EXPORT_SYMBOL_GPL(add_page_wait_queue);
-#ifndef clear_bit_unlock_is_negative_byte
-
-/*
- * PG_waiters is the high bit in the same byte as PG_lock.
- *
- * On x86 (and on many other architectures), we can clear PG_lock and
- * test the sign bit at the same time. But if the architecture does
- * not support that special operation, we just do this all by hand
- * instead.
- *
- * The read of PG_waiters has to be after (or concurrently with) PG_locked
- * being cleared, but a memory barrier should be unneccssary since it is
- * in the same byte as PG_locked.
- */
-static inline bool clear_bit_unlock_is_negative_byte(long nr, volatile void *mem)
-{
- clear_bit_unlock(nr, mem);
- /* smp_mb__after_atomic(); */
- return test_bit(PG_waiters, mem);
-}
-
-#endif
-
/**
* unlock_page - unlock a locked page
* @page: the page
--
2.25.1
next prev parent reply other threads:[~2020-03-26 12:24 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-26 12:24 [PATCH 0/2] Make PageWriteback use the PageLocked optimisation Matthew Wilcox
2020-03-26 12:24 ` Matthew Wilcox [this message]
2020-04-16 12:45 ` [PATCH 1/2] mm: Remove definition of clear_bit_unlock_is_negative_byte Will Deacon
2020-04-16 14:31 ` Matthew Wilcox
2020-03-26 12:24 ` [PATCH 2/2] mm: Use clear_bit_unlock_is_negative_byte for PageWriteback Matthew Wilcox
2020-03-26 12:40 ` Jan Kara
2020-03-26 12:44 ` Matthew Wilcox
2020-03-27 10:46 ` William Kucharski
2020-03-26 17:11 ` Christoph Hellwig
2020-03-26 17:16 ` Matthew Wilcox
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