The patch titled
Subject: atomic: implement generic atomic_dec_if_positive()
has been added to the -mm tree. Its filename is
atomic-implement-generic-atomic_dec_if_positive.patch
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------------------------------------------------------
From: Shaohua Li <shli@xxxxxxxxxx>
Subject: atomic: implement generic atomic_dec_if_positive()
The x86 implementation of atomic_dec_if_positive is quite generic, so make
it available to all architectures.
This is needed for "swap: add a simple detector for inappropriate swapin
readahead".
Signed-off-by: Shaohua Li <shli@xxxxxxxxxxxx>
Cc: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>
Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Cc: Michal Simek <monstr@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/microblaze/include/asm/atomic.h | 3 ++-
arch/powerpc/include/asm/atomic.h | 3 ++-
arch/x86/include/asm/atomic.h | 24 ------------------------
include/linux/atomic.h | 25 +++++++++++++++++++++++++
4 files changed, 29 insertions(+), 26 deletions(-)
diff -puN arch/microblaze/include/asm/atomic.h~atomic-implement-generic-atomic_dec_if_positive arch/microblaze/include/asm/atomic.h
--- a/arch/microblaze/include/asm/atomic.h~atomic-implement-generic-atomic_dec_if_positive
+++ a/arch/microblaze/include/asm/atomic.h
@@ -9,7 +9,7 @@
* Atomically test *v and decrement if it is greater than 0.
* The function returns the old value of *v minus 1.
*/
-static inline int atomic_dec_if_positive(atomic_t *v)
+static inline int __atomic_dec_if_positive(atomic_t *v)
{
unsigned long flags;
int res;
@@ -22,5 +22,6 @@ static inline int atomic_dec_if_positive
return res;
}
+#define atomic_dec_if_positive __atomic_dec_if_positive
#endif /* _ASM_MICROBLAZE_ATOMIC_H */
diff -puN arch/powerpc/include/asm/atomic.h~atomic-implement-generic-atomic_dec_if_positive arch/powerpc/include/asm/atomic.h
--- a/arch/powerpc/include/asm/atomic.h~atomic-implement-generic-atomic_dec_if_positive
+++ a/arch/powerpc/include/asm/atomic.h
@@ -247,7 +247,7 @@ static __inline__ int atomic_inc_not_zer
* The function returns the old value of *v minus 1, even if
* the atomic variable, v, was not decremented.
*/
-static __inline__ int atomic_dec_if_positive(atomic_t *v)
+static __inline__ int __atomic_dec_if_positive(atomic_t *v)
{
int t;
@@ -268,6 +268,7 @@ static __inline__ int atomic_dec_if_posi
return t;
}
+#define atomic_dec_if_positive __atomic_dec_if_positive
#define smp_mb__before_atomic_dec() smp_mb()
#define smp_mb__after_atomic_dec() smp_mb()
diff -puN arch/x86/include/asm/atomic.h~atomic-implement-generic-atomic_dec_if_positive arch/x86/include/asm/atomic.h
--- a/arch/x86/include/asm/atomic.h~atomic-implement-generic-atomic_dec_if_positive
+++ a/arch/x86/include/asm/atomic.h
@@ -240,30 +240,6 @@ static inline int __atomic_add_unless(at
return c;
}
-
-/*
- * atomic_dec_if_positive - decrement by 1 if old value positive
- * @v: pointer of type atomic_t
- *
- * The function returns the old value of *v minus 1, even if
- * the atomic variable, v, was not decremented.
- */
-static inline int atomic_dec_if_positive(atomic_t *v)
-{
- int c, old, dec;
- c = atomic_read(v);
- for (;;) {
- dec = c - 1;
- if (unlikely(dec < 0))
- break;
- old = atomic_cmpxchg((v), c, dec);
- if (likely(old == c))
- break;
- c = old;
- }
- return dec;
-}
-
/**
* atomic_inc_short - increment of a short integer
* @v: pointer to type int
diff -puN include/linux/atomic.h~atomic-implement-generic-atomic_dec_if_positive include/linux/atomic.h
--- a/include/linux/atomic.h~atomic-implement-generic-atomic_dec_if_positive
+++ a/include/linux/atomic.h
@@ -86,6 +86,31 @@ static inline int atomic_dec_unless_posi
}
#endif
+/*
+ * atomic_dec_if_positive - decrement by 1 if old value positive
+ * @v: pointer of type atomic_t
+ *
+ * The function returns the old value of *v minus 1, even if
+ * the atomic variable, v, was not decremented.
+ */
+#ifndef atomic_dec_if_positive
+static inline int atomic_dec_if_positive(atomic_t *v)
+{
+ int c, old, dec;
+ c = atomic_read(v);
+ for (;;) {
+ dec = c - 1;
+ if (unlikely(dec < 0))
+ break;
+ old = atomic_cmpxchg((v), c, dec);
+ if (likely(old == c))
+ break;
+ c = old;
+ }
+ return dec;
+}
+#endif
+
#ifndef CONFIG_ARCH_HAS_ATOMIC_OR
static inline void atomic_or(int i, atomic_t *v)
{
_
Patches currently in -mm which might be from shli@xxxxxxxxxx are
linux-next.patch
readahead-fault-retry-breaks-mmap-file-read-random-detection.patch
atomic-implement-generic-atomic_dec_if_positive.patch
swap-add-a-simple-detector-for-inappropriate-swapin-readahead.patch
swap-add-a-simple-detector-for-inappropriate-swapin-readahead-fix.patch
mm-compaction-abort-compaction-loop-if-lock-is-contended-or-run-too-long.patch
mm-compaction-abort-compaction-loop-if-lock-is-contended-or-run-too-long-fix.patch
mm-compaction-check-lock-contention-first-before-taking-lock.patch
mm-compaction-move-fatal-signal-check-out-of-compact_checklock_irqsave.patch
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