Jeremy Fitzhardinge
2011-Nov-09 01:17 UTC
[Xen-devel] [GIT PULL] More cleanups for atomic memory operations/spinlocks
I forgot to push these for the just-closed merge window, but they''re
fine for the next one. Could you find them a home in tip.git?
Thanks,
J
The following changes since commit 1ea6b8f48918282bdca0b32a34095504ee65bab5:
Linux 3.2-rc1 (2011-11-07 16:16:02 -0800)
are available in the git repository at:
git://git.kernel.org/pub/scm/linux/kernel/git/jeremy/xen.git
upstream/ticketlock-cleanup
Jeremy Fitzhardinge (2):
x86/cmpxchg: add a locked add() helper
x86: consolidate xchg and xadd macros
arch/x86/include/asm/cmpxchg.h | 140 +++++++++++++++++++-------------------
arch/x86/include/asm/spinlock.h | 15 +----
2 files changed, 71 insertions(+), 84 deletions(-)
diff --git a/arch/x86/include/asm/cmpxchg.h b/arch/x86/include/asm/cmpxchg.h
index 5d3acdf..5488e10 100644
--- a/arch/x86/include/asm/cmpxchg.h
+++ b/arch/x86/include/asm/cmpxchg.h
@@ -14,6 +14,8 @@ extern void __cmpxchg_wrong_size(void)
__compiletime_error("Bad argument size for cmpxchg");
extern void __xadd_wrong_size(void)
__compiletime_error("Bad argument size for xadd");
+extern void __add_wrong_size(void)
+ __compiletime_error("Bad argument size for add");
/*
* Constants for operation sizes. On 32-bit, the 64-bit size it set to
@@ -31,60 +33,47 @@ extern void __xadd_wrong_size(void)
#define __X86_CASE_Q -1 /* sizeof will never return -1 */
#endif
+/*
+ * An exchange-type operation, which takes a value and a pointer, and
+ * returns a the old value.
+ */
+#define __xchg_op(ptr, arg, op, lock) \
+ ({ \
+ __typeof__ (*(ptr)) __ret = (arg); \
+ switch (sizeof(*(ptr))) { \
+ case __X86_CASE_B: \
+ asm volatile (lock #op "b %b0, %1\n" \
+ : "+r" (__ret), "+m" (*(ptr)) \
+ : : "memory", "cc"); \
+ break; \
+ case __X86_CASE_W: \
+ asm volatile (lock #op "w %w0, %1\n" \
+ : "+r" (__ret), "+m" (*(ptr)) \
+ : : "memory", "cc"); \
+ break; \
+ case __X86_CASE_L: \
+ asm volatile (lock #op "l %0, %1\n" \
+ : "+r" (__ret), "+m" (*(ptr)) \
+ : : "memory", "cc"); \
+ break; \
+ case __X86_CASE_Q: \
+ asm volatile (lock #op "q %q0, %1\n" \
+ : "+r" (__ret), "+m" (*(ptr)) \
+ : : "memory", "cc"); \
+ break; \
+ default: \
+ __ ## op ## _wrong_size(); \
+ } \
+ __ret; \
+ })
+
/*
* Note: no "lock" prefix even on SMP: xchg always implies lock
anyway.
* Since this is generally used to protect other memory information, we
* use "asm volatile" and "memory" clobbers to prevent gcc
from moving
* information around.
*/
-#define __xchg(x, ptr, size) \
-({ \
- __typeof(*(ptr)) __x = (x); \
- switch (size) { \
- case __X86_CASE_B: \
- { \
- volatile u8 *__ptr = (volatile u8 *)(ptr); \
- asm volatile("xchgb %0,%1" \
- : "=q" (__x), "+m" (*__ptr) \
- : "0" (__x) \
- : "memory"); \
- break; \
- } \
- case __X86_CASE_W: \
- { \
- volatile u16 *__ptr = (volatile u16 *)(ptr); \
- asm volatile("xchgw %0,%1" \
- : "=r" (__x), "+m" (*__ptr) \
- : "0" (__x) \
- : "memory"); \
- break; \
- } \
- case __X86_CASE_L: \
- { \
- volatile u32 *__ptr = (volatile u32 *)(ptr); \
- asm volatile("xchgl %0,%1" \
- : "=r" (__x), "+m" (*__ptr) \
- : "0" (__x) \
- : "memory"); \
- break; \
- } \
- case __X86_CASE_Q: \
- { \
- volatile u64 *__ptr = (volatile u64 *)(ptr); \
- asm volatile("xchgq %0,%1" \
- : "=r" (__x), "+m" (*__ptr) \
- : "0" (__x) \
- : "memory"); \
- break; \
- } \
- default: \
- __xchg_wrong_size(); \
- } \
- __x; \
-})
-
-#define xchg(ptr, v) \
- __xchg((v), (ptr), sizeof(*ptr))
+#define xchg(ptr, v) __xchg_op((ptr), (v), xchg, "")
/*
* Atomic compare and exchange. Compare OLD with MEM, if identical,
@@ -165,46 +154,57 @@ extern void __xadd_wrong_size(void)
__cmpxchg_local((ptr), (old), (new), sizeof(*ptr))
#endif
-#define __xadd(ptr, inc, lock) \
+/*
+ * xadd() adds "inc" to "*ptr" and atomically returns the
previous
+ * value of "*ptr".
+ *
+ * xadd() is locked when multiple CPUs are online
+ * xadd_sync() is always locked
+ * xadd_local() is never locked
+ */
+#define __xadd(ptr, inc, lock) __xchg_op((ptr), (inc), xadd, lock)
+#define xadd(ptr, inc) __xadd((ptr), (inc), LOCK_PREFIX)
+#define xadd_sync(ptr, inc) __xadd((ptr), (inc), "lock; ")
+#define xadd_local(ptr, inc) __xadd((ptr), (inc), "")
+
+#define __add(ptr, inc, lock) \
({ \
__typeof__ (*(ptr)) __ret = (inc); \
switch (sizeof(*(ptr))) { \
case __X86_CASE_B: \
- asm volatile (lock "xaddb %b0, %1\n" \
- : "+r" (__ret), "+m" (*(ptr)) \
- : : "memory", "cc"); \
+ asm volatile (lock "addb %b1, %0\n" \
+ : "+m" (*(ptr)) : "ri" (inc) \
+ : "memory", "cc"); \
break; \
case __X86_CASE_W: \
- asm volatile (lock "xaddw %w0, %1\n" \
- : "+r" (__ret), "+m" (*(ptr)) \
- : : "memory", "cc"); \
+ asm volatile (lock "addw %w1, %0\n" \
+ : "+m" (*(ptr)) : "ri" (inc) \
+ : "memory", "cc"); \
break; \
case __X86_CASE_L: \
- asm volatile (lock "xaddl %0, %1\n" \
- : "+r" (__ret), "+m" (*(ptr)) \
- : : "memory", "cc"); \
+ asm volatile (lock "addl %1, %0\n" \
+ : "+m" (*(ptr)) : "ri" (inc) \
+ : "memory", "cc"); \
break; \
case __X86_CASE_Q: \
- asm volatile (lock "xaddq %q0, %1\n" \
- : "+r" (__ret), "+m" (*(ptr)) \
- : : "memory", "cc"); \
+ asm volatile (lock "addq %1, %0\n" \
+ : "+m" (*(ptr)) : "ri" (inc) \
+ : "memory", "cc"); \
break; \
default: \
- __xadd_wrong_size(); \
+ __add_wrong_size(); \
} \
__ret; \
})
/*
- * xadd() adds "inc" to "*ptr" and atomically returns the
previous
- * value of "*ptr".
+ * add_*() adds "inc" to "*ptr"
*
- * xadd() is locked when multiple CPUs are online
- * xadd_sync() is always locked
- * xadd_local() is never locked
+ * __add() takes a lock prefix
+ * add_smp() is locked when multiple CPUs are online
+ * add_sync() is always locked
*/
-#define xadd(ptr, inc) __xadd((ptr), (inc), LOCK_PREFIX)
-#define xadd_sync(ptr, inc) __xadd((ptr), (inc), "lock; ")
-#define xadd_local(ptr, inc) __xadd((ptr), (inc), "")
+#define add_smp(ptr, inc) __add((ptr), (inc), LOCK_PREFIX)
+#define add_sync(ptr, inc) __add((ptr), (inc), "lock; ")
#endif /* ASM_X86_CMPXCHG_H */
diff --git a/arch/x86/include/asm/spinlock.h b/arch/x86/include/asm/spinlock.h
index 972c260..a82c2bf 100644
--- a/arch/x86/include/asm/spinlock.h
+++ b/arch/x86/include/asm/spinlock.h
@@ -79,23 +79,10 @@ static __always_inline int
__ticket_spin_trylock(arch_spinlock_t *lock)
return cmpxchg(&lock->head_tail, old.head_tail, new.head_tail) ==
old.head_tail;
}
-#if (NR_CPUS < 256)
static __always_inline void __ticket_spin_unlock(arch_spinlock_t *lock)
{
- asm volatile(UNLOCK_LOCK_PREFIX "incb %0"
- : "+m" (lock->head_tail)
- :
- : "memory", "cc");
+ __add(&lock->tickets.head, 1, UNLOCK_LOCK_PREFIX);
}
-#else
-static __always_inline void __ticket_spin_unlock(arch_spinlock_t *lock)
-{
- asm volatile(UNLOCK_LOCK_PREFIX "incw %0"
- : "+m" (lock->head_tail)
- :
- : "memory", "cc");
-}
-#endif
static inline int __ticket_spin_is_locked(arch_spinlock_t *lock)
{
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Jeremy Fitzhardinge
2011-Nov-11 20:03 UTC
[Xen-devel] Re: [GIT PULL] More cleanups for atomic memory operations/spinlocks
Ping? On 11/08/2011 05:17 PM, Jeremy Fitzhardinge wrote:> I forgot to push these for the just-closed merge window, but they''re > fine for the next one. Could you find them a home in tip.git? > > Thanks, > J > > The following changes since commit 1ea6b8f48918282bdca0b32a34095504ee65bab5: > > Linux 3.2-rc1 (2011-11-07 16:16:02 -0800) > > are available in the git repository at: > git://git.kernel.org/pub/scm/linux/kernel/git/jeremy/xen.git upstream/ticketlock-cleanup > > Jeremy Fitzhardinge (2): > x86/cmpxchg: add a locked add() helper > x86: consolidate xchg and xadd macros > > arch/x86/include/asm/cmpxchg.h | 140 +++++++++++++++++++------------------- > arch/x86/include/asm/spinlock.h | 15 +---- > 2 files changed, 71 insertions(+), 84 deletions(-) > > diff --git a/arch/x86/include/asm/cmpxchg.h b/arch/x86/include/asm/cmpxchg.h > index 5d3acdf..5488e10 100644 > --- a/arch/x86/include/asm/cmpxchg.h > +++ b/arch/x86/include/asm/cmpxchg.h > @@ -14,6 +14,8 @@ extern void __cmpxchg_wrong_size(void) > __compiletime_error("Bad argument size for cmpxchg"); > extern void __xadd_wrong_size(void) > __compiletime_error("Bad argument size for xadd"); > +extern void __add_wrong_size(void) > + __compiletime_error("Bad argument size for add"); > > /* > * Constants for operation sizes. On 32-bit, the 64-bit size it set to > @@ -31,60 +33,47 @@ extern void __xadd_wrong_size(void) > #define __X86_CASE_Q -1 /* sizeof will never return -1 */ > #endif > > +/* > + * An exchange-type operation, which takes a value and a pointer, and > + * returns a the old value. > + */ > +#define __xchg_op(ptr, arg, op, lock) \ > + ({ \ > + __typeof__ (*(ptr)) __ret = (arg); \ > + switch (sizeof(*(ptr))) { \ > + case __X86_CASE_B: \ > + asm volatile (lock #op "b %b0, %1\n" \ > + : "+r" (__ret), "+m" (*(ptr)) \ > + : : "memory", "cc"); \ > + break; \ > + case __X86_CASE_W: \ > + asm volatile (lock #op "w %w0, %1\n" \ > + : "+r" (__ret), "+m" (*(ptr)) \ > + : : "memory", "cc"); \ > + break; \ > + case __X86_CASE_L: \ > + asm volatile (lock #op "l %0, %1\n" \ > + : "+r" (__ret), "+m" (*(ptr)) \ > + : : "memory", "cc"); \ > + break; \ > + case __X86_CASE_Q: \ > + asm volatile (lock #op "q %q0, %1\n" \ > + : "+r" (__ret), "+m" (*(ptr)) \ > + : : "memory", "cc"); \ > + break; \ > + default: \ > + __ ## op ## _wrong_size(); \ > + } \ > + __ret; \ > + }) > + > /* > * Note: no "lock" prefix even on SMP: xchg always implies lock anyway. > * Since this is generally used to protect other memory information, we > * use "asm volatile" and "memory" clobbers to prevent gcc from moving > * information around. > */ > -#define __xchg(x, ptr, size) \ > -({ \ > - __typeof(*(ptr)) __x = (x); \ > - switch (size) { \ > - case __X86_CASE_B: \ > - { \ > - volatile u8 *__ptr = (volatile u8 *)(ptr); \ > - asm volatile("xchgb %0,%1" \ > - : "=q" (__x), "+m" (*__ptr) \ > - : "0" (__x) \ > - : "memory"); \ > - break; \ > - } \ > - case __X86_CASE_W: \ > - { \ > - volatile u16 *__ptr = (volatile u16 *)(ptr); \ > - asm volatile("xchgw %0,%1" \ > - : "=r" (__x), "+m" (*__ptr) \ > - : "0" (__x) \ > - : "memory"); \ > - break; \ > - } \ > - case __X86_CASE_L: \ > - { \ > - volatile u32 *__ptr = (volatile u32 *)(ptr); \ > - asm volatile("xchgl %0,%1" \ > - : "=r" (__x), "+m" (*__ptr) \ > - : "0" (__x) \ > - : "memory"); \ > - break; \ > - } \ > - case __X86_CASE_Q: \ > - { \ > - volatile u64 *__ptr = (volatile u64 *)(ptr); \ > - asm volatile("xchgq %0,%1" \ > - : "=r" (__x), "+m" (*__ptr) \ > - : "0" (__x) \ > - : "memory"); \ > - break; \ > - } \ > - default: \ > - __xchg_wrong_size(); \ > - } \ > - __x; \ > -}) > - > -#define xchg(ptr, v) \ > - __xchg((v), (ptr), sizeof(*ptr)) > +#define xchg(ptr, v) __xchg_op((ptr), (v), xchg, "") > > /* > * Atomic compare and exchange. Compare OLD with MEM, if identical, > @@ -165,46 +154,57 @@ extern void __xadd_wrong_size(void) > __cmpxchg_local((ptr), (old), (new), sizeof(*ptr)) > #endif > > -#define __xadd(ptr, inc, lock) \ > +/* > + * xadd() adds "inc" to "*ptr" and atomically returns the previous > + * value of "*ptr". > + * > + * xadd() is locked when multiple CPUs are online > + * xadd_sync() is always locked > + * xadd_local() is never locked > + */ > +#define __xadd(ptr, inc, lock) __xchg_op((ptr), (inc), xadd, lock) > +#define xadd(ptr, inc) __xadd((ptr), (inc), LOCK_PREFIX) > +#define xadd_sync(ptr, inc) __xadd((ptr), (inc), "lock; ") > +#define xadd_local(ptr, inc) __xadd((ptr), (inc), "") > + > +#define __add(ptr, inc, lock) \ > ({ \ > __typeof__ (*(ptr)) __ret = (inc); \ > switch (sizeof(*(ptr))) { \ > case __X86_CASE_B: \ > - asm volatile (lock "xaddb %b0, %1\n" \ > - : "+r" (__ret), "+m" (*(ptr)) \ > - : : "memory", "cc"); \ > + asm volatile (lock "addb %b1, %0\n" \ > + : "+m" (*(ptr)) : "ri" (inc) \ > + : "memory", "cc"); \ > break; \ > case __X86_CASE_W: \ > - asm volatile (lock "xaddw %w0, %1\n" \ > - : "+r" (__ret), "+m" (*(ptr)) \ > - : : "memory", "cc"); \ > + asm volatile (lock "addw %w1, %0\n" \ > + : "+m" (*(ptr)) : "ri" (inc) \ > + : "memory", "cc"); \ > break; \ > case __X86_CASE_L: \ > - asm volatile (lock "xaddl %0, %1\n" \ > - : "+r" (__ret), "+m" (*(ptr)) \ > - : : "memory", "cc"); \ > + asm volatile (lock "addl %1, %0\n" \ > + : "+m" (*(ptr)) : "ri" (inc) \ > + : "memory", "cc"); \ > break; \ > case __X86_CASE_Q: \ > - asm volatile (lock "xaddq %q0, %1\n" \ > - : "+r" (__ret), "+m" (*(ptr)) \ > - : : "memory", "cc"); \ > + asm volatile (lock "addq %1, %0\n" \ > + : "+m" (*(ptr)) : "ri" (inc) \ > + : "memory", "cc"); \ > break; \ > default: \ > - __xadd_wrong_size(); \ > + __add_wrong_size(); \ > } \ > __ret; \ > }) > > /* > - * xadd() adds "inc" to "*ptr" and atomically returns the previous > - * value of "*ptr". > + * add_*() adds "inc" to "*ptr" > * > - * xadd() is locked when multiple CPUs are online > - * xadd_sync() is always locked > - * xadd_local() is never locked > + * __add() takes a lock prefix > + * add_smp() is locked when multiple CPUs are online > + * add_sync() is always locked > */ > -#define xadd(ptr, inc) __xadd((ptr), (inc), LOCK_PREFIX) > -#define xadd_sync(ptr, inc) __xadd((ptr), (inc), "lock; ") > -#define xadd_local(ptr, inc) __xadd((ptr), (inc), "") > +#define add_smp(ptr, inc) __add((ptr), (inc), LOCK_PREFIX) > +#define add_sync(ptr, inc) __add((ptr), (inc), "lock; ") > > #endif /* ASM_X86_CMPXCHG_H */ > diff --git a/arch/x86/include/asm/spinlock.h b/arch/x86/include/asm/spinlock.h > index 972c260..a82c2bf 100644 > --- a/arch/x86/include/asm/spinlock.h > +++ b/arch/x86/include/asm/spinlock.h > @@ -79,23 +79,10 @@ static __always_inline int __ticket_spin_trylock(arch_spinlock_t *lock) > return cmpxchg(&lock->head_tail, old.head_tail, new.head_tail) == old.head_tail; > } > > -#if (NR_CPUS < 256) > static __always_inline void __ticket_spin_unlock(arch_spinlock_t *lock) > { > - asm volatile(UNLOCK_LOCK_PREFIX "incb %0" > - : "+m" (lock->head_tail) > - : > - : "memory", "cc"); > + __add(&lock->tickets.head, 1, UNLOCK_LOCK_PREFIX); > } > -#else > -static __always_inline void __ticket_spin_unlock(arch_spinlock_t *lock) > -{ > - asm volatile(UNLOCK_LOCK_PREFIX "incw %0" > - : "+m" (lock->head_tail) > - : > - : "memory", "cc"); > -} > -#endif > > static inline int __ticket_spin_is_locked(arch_spinlock_t *lock) > { > >_______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
Ingo Molnar
2011-Dec-05 09:56 UTC
Re: [GIT PULL] More cleanups for atomic memory operations/spinlocks
* Jeremy Fitzhardinge <jeremy@goop.org> wrote:> I forgot to push these for the just-closed merge window, but they''re > fine for the next one. Could you find them a home in tip.git? > > Thanks, > J > > The following changes since commit 1ea6b8f48918282bdca0b32a34095504ee65bab5: > > Linux 3.2-rc1 (2011-11-07 16:16:02 -0800) > > are available in the git repository at: > git://git.kernel.org/pub/scm/linux/kernel/git/jeremy/xen.git upstream/ticketlock-cleanup > > Jeremy Fitzhardinge (2): > x86/cmpxchg: add a locked add() helper > x86: consolidate xchg and xadd macros > > arch/x86/include/asm/cmpxchg.h | 140 +++++++++++++++++++------------------- > arch/x86/include/asm/spinlock.h | 15 +---- > 2 files changed, 71 insertions(+), 84 deletions(-)Pulled it into x86/asm for testing, thanks Jeremy. Peter, any objections? Thanks, Ingo
H. Peter Anvin
2011-Dec-05 10:00 UTC
Re: [GIT PULL] More cleanups for atomic memory operations/spinlocks
On 12/05/2011 01:56 AM, Ingo Molnar wrote:> > Pulled it into x86/asm for testing, thanks Jeremy. > > Peter, any objections? >No. Thank you! -hpa -- H. Peter Anvin, Intel Open Source Technology Center I work for Intel. I don''t speak on their behalf.