From d688abf50bd5a30d2c44dea2a72dd59052cd3cce Mon Sep 17 00:00:00 2001
From: Andrew Morton <akpm@osdl.org>
Date: Thu, 19 Jul 2007 01:49:17 -0700
Subject: [PATCH] move page writeback acounting out of macros
page-writeback accounting is presently performed in the page-flags macros.
This is inconsistent and a bit ugly and makes it awkward to implement
per-backing_dev under-writeback page accounting.
So move this accounting down to the callsite(s).
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
include/linux/page-flags.h | 38 ++++++++------------------------------
mm/page-writeback.c | 4 ++++
2 files changed, 12 insertions(+), 30 deletions(-)
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index a454176c3e306..209d3a47f50f2 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -189,37 +189,15 @@ static inline void SetPageUptodate(struct page *page)
#define __SetPagePrivate(page) __set_bit(PG_private, &(page)->flags)
#define __ClearPagePrivate(page) __clear_bit(PG_private, &(page)->flags)
+/*
+ * Only test-and-set exist for PG_writeback. The unconditional operators are
+ * risky: they bypass page accounting.
+ */
#define PageWriteback(page) test_bit(PG_writeback, &(page)->flags)
-#define SetPageWriteback(page) \
- do { \
- if (!test_and_set_bit(PG_writeback, \
- &(page)->flags)) \
- inc_zone_page_state(page, NR_WRITEBACK); \
- } while (0)
-#define TestSetPageWriteback(page) \
- ({ \
- int ret; \
- ret = test_and_set_bit(PG_writeback, \
- &(page)->flags); \
- if (!ret) \
- inc_zone_page_state(page, NR_WRITEBACK); \
- ret; \
- })
-#define ClearPageWriteback(page) \
- do { \
- if (test_and_clear_bit(PG_writeback, \
- &(page)->flags)) \
- dec_zone_page_state(page, NR_WRITEBACK); \
- } while (0)
-#define TestClearPageWriteback(page) \
- ({ \
- int ret; \
- ret = test_and_clear_bit(PG_writeback, \
- &(page)->flags); \
- if (ret) \
- dec_zone_page_state(page, NR_WRITEBACK); \
- ret; \
- })
+#define TestSetPageWriteback(page) test_and_set_bit(PG_writeback, \
+ &(page)->flags)
+#define TestClearPageWriteback(page) test_and_clear_bit(PG_writeback, \
+ &(page)->flags)
#define PageBuddy(page) test_bit(PG_buddy, &(page)->flags)
#define __SetPageBuddy(page) __set_bit(PG_buddy, &(page)->flags)
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 51b3eb6ab445e..63512a9ed57e7 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -987,6 +987,8 @@ int test_clear_page_writeback(struct page *page)
} else {
ret = TestClearPageWriteback(page);
}
+ if (ret)
+ dec_zone_page_state(page, NR_WRITEBACK);
return ret;
}
@@ -1012,6 +1014,8 @@ int test_set_page_writeback(struct page *page)
} else {
ret = TestSetPageWriteback(page);
}
+ if (!ret)
+ inc_zone_page_state(page, NR_WRITEBACK);
return ret;
}
--
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