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authorSiddhesh Poyarekar <siddhesh@redhat.com>2012-11-05 21:12:10 +0530
committerSiddhesh Poyarekar <siddhesh@redhat.com>2012-11-05 21:12:52 +0530
commit8f861542dd0603bef99e126e509ece89514c1eeb (patch)
tree083f3bd20edfa09a2341e0340013c0781b4696ad /nptl
parent155ee340b875834693fbd1b7401af7fe88ace04d (diff)
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[S390,PPC] Implement FUTEX_WAIT_BITSET for timedwait functions
Since the FUTEX_WAIT operation takes a relative timeout, the pthread_cond_timedwait and other timed function implementations have to get a relative timeout from the absolute timeout parameter it gets before it makes the futex syscall. This value is then converted back into an absolute timeout within the kernel. This is a waste and has hence been improved upon by a FUTEX_WAIT_BITSET operation (OR'd with FUTEX_CLOCK_REALTIME to make the kernel use the realtime clock instead of the default monotonic clock). This was implemented only in the x86 and sh assembly code and not in the C code. This patch implements support for FUTEX_WAIT_BITSET whenever available (since linux-2.6.29) for s390 and powerpc.
Diffstat (limited to 'nptl')
-rw-r--r--nptl/ChangeLog17
-rw-r--r--nptl/pthread_cond_timedwait.c22
-rw-r--r--nptl/pthread_rwlock_timedrdlock.c21
-rw-r--r--nptl/pthread_rwlock_timedwrlock.c21
-rw-r--r--nptl/sysdeps/unix/sysv/linux/lowlevelrobustlock.c16
-rw-r--r--nptl/sysdeps/unix/sysv/linux/powerpc/lowlevellock.h13
-rw-r--r--nptl/sysdeps/unix/sysv/linux/s390/lowlevellock.h20
7 files changed, 124 insertions, 6 deletions
diff --git a/nptl/ChangeLog b/nptl/ChangeLog
index a7b741f..0e01675 100644
--- a/nptl/ChangeLog
+++ b/nptl/ChangeLog
@@ -1,3 +1,20 @@
+2012-11-05 Siddhesh Poyarekar <siddhesh@redhat.com>
+
+ * pthread_cond_timedwait.c (__pthread_cond_timedwait): Time out
+ if absolute timeout is negative.
+ [__ASSUME_FUTEX_CLOCK_REALTIME &&
+ lll_futex_timed_wait_bitset]: Use lll_futex_timed_wait_bitset.
+ * pthread_rwlock_timedrdlock.c (pthread_rwlock_timedrdlock):
+ Likewise.
+ * pthread_rwlock_timedwrlock.c (pthread_rwlock_timedwrlock):
+ Likewise.
+ * sysdeps/unix/sysv/linux/lowlevelrobustlock.c
+ (__lll_robust_timedlock_wait): Likewise.
+ * sysdeps/unix/sysv/linux/powerpc/lowlevellock.h
+ (lll_futex_timed_wait_bitset): New macro.
+ * sysdeps/unix/sysv/linux/s390/lowlevellock.h
+ (lll_futex_timed_wait_bitset): Likewise.
+
2012-11-03 David S. Miller <davem@davemloft.net>
* sysdeps/unix/sysv/linux/sparc/lowlevellock.h (BUSY_WAIT_NOP):
diff --git a/nptl/pthread_cond_timedwait.c b/nptl/pthread_cond_timedwait.c
index 51a34ba..2fcbc57 100644
--- a/nptl/pthread_cond_timedwait.c
+++ b/nptl/pthread_cond_timedwait.c
@@ -80,6 +80,11 @@ __pthread_cond_timedwait (cond, mutex, abstime)
++cond->__data.__futex;
cond->__data.__nwaiters += 1 << COND_NWAITERS_SHIFT;
+ /* Work around the fact that the kernel rejects negative timeout values
+ despite them being valid. */
+ if (__builtin_expect (abstime->tv_sec < 0, 0))
+ goto timeout;
+
/* Remember the mutex we are using here. If there is already a
different address store this is a bad user bug. Do not store
anything for pshared condvars. */
@@ -104,9 +109,11 @@ __pthread_cond_timedwait (cond, mutex, abstime)
while (1)
{
+#if (!defined __ASSUME_FUTEX_CLOCK_REALTIME \
+ || !defined lll_futex_timed_wait_bitset)
struct timespec rt;
{
-#ifdef __NR_clock_gettime
+# ifdef __NR_clock_gettime
INTERNAL_SYSCALL_DECL (err);
int ret;
ret = INTERNAL_VSYSCALL (clock_gettime, err, 2,
@@ -116,7 +123,7 @@ __pthread_cond_timedwait (cond, mutex, abstime)
/* Convert the absolute timeout value to a relative timeout. */
rt.tv_sec = abstime->tv_sec - rt.tv_sec;
rt.tv_nsec = abstime->tv_nsec - rt.tv_nsec;
-#else
+# else
/* Get the current time. So far we support only one clock. */
struct timeval tv;
(void) gettimeofday (&tv, NULL);
@@ -124,7 +131,7 @@ __pthread_cond_timedwait (cond, mutex, abstime)
/* Convert the absolute timeout value to a relative timeout. */
rt.tv_sec = abstime->tv_sec - tv.tv_sec;
rt.tv_nsec = abstime->tv_nsec - tv.tv_usec * 1000;
-#endif
+# endif
}
if (rt.tv_nsec < 0)
{
@@ -139,6 +146,7 @@ __pthread_cond_timedwait (cond, mutex, abstime)
goto timeout;
}
+#endif
unsigned int futex_val = cond->__data.__futex;
@@ -148,9 +156,17 @@ __pthread_cond_timedwait (cond, mutex, abstime)
/* Enable asynchronous cancellation. Required by the standard. */
cbuffer.oldtype = __pthread_enable_asynccancel ();
+#if (!defined __ASSUME_FUTEX_CLOCK_REALTIME \
+ || !defined lll_futex_timed_wait_bitset)
/* Wait until woken by signal or broadcast. */
err = lll_futex_timed_wait (&cond->__data.__futex,
futex_val, &rt, pshared);
+#else
+ unsigned int clockbit = (cond->__data.__nwaiters & 1
+ ? 0 : FUTEX_CLOCK_REALTIME);
+ err = lll_futex_timed_wait_bitset (&cond->__data.__futex, futex_val,
+ abstime, clockbit, pshared);
+#endif
/* Disable asynchronous cancellation. */
__pthread_disable_asynccancel (cbuffer.oldtype);
diff --git a/nptl/pthread_rwlock_timedrdlock.c b/nptl/pthread_rwlock_timedrdlock.c
index be8216d..b7622ab 100644
--- a/nptl/pthread_rwlock_timedrdlock.c
+++ b/nptl/pthread_rwlock_timedrdlock.c
@@ -1,4 +1,4 @@
-/* Copyright (C) 2003,2004,2007,2011 Free Software Foundation, Inc.
+/* Copyright (C) 2003-2012 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Martin Schwidefsky <schwidefsky@de.ibm.com>, 2003.
@@ -76,6 +76,16 @@ pthread_rwlock_timedrdlock (rwlock, abstime)
break;
}
+ /* Work around the fact that the kernel rejects negative timeout values
+ despite them being valid. */
+ if (__builtin_expect (abstime->tv_sec < 0, 0))
+ {
+ result = ETIMEDOUT;
+ break;
+ }
+
+#if (!defined __ASSUME_FUTEX_CLOCK_REALTIME \
+ || !defined lll_futex_timed_wait_bitset)
/* Get the current time. So far we support only one clock. */
struct timeval tv;
(void) gettimeofday (&tv, NULL);
@@ -96,6 +106,7 @@ pthread_rwlock_timedrdlock (rwlock, abstime)
result = ETIMEDOUT;
break;
}
+#endif
/* Remember that we are a reader. */
if (++rwlock->__data.__nr_readers_queued == 0)
@@ -112,8 +123,16 @@ pthread_rwlock_timedrdlock (rwlock, abstime)
lll_unlock (rwlock->__data.__lock, rwlock->__data.__shared);
/* Wait for the writer to finish. */
+#if (!defined __ASSUME_FUTEX_CLOCK_REALTIME \
+ || !defined lll_futex_timed_wait_bitset)
err = lll_futex_timed_wait (&rwlock->__data.__readers_wakeup,
waitval, &rt, rwlock->__data.__shared);
+#else
+ err = lll_futex_timed_wait_bitset (&rwlock->__data.__readers_wakeup,
+ waitval, abstime,
+ FUTEX_CLOCK_REALTIME,
+ rwlock->__data.__shared);
+#endif
/* Get the lock. */
lll_lock (rwlock->__data.__lock, rwlock->__data.__shared);
diff --git a/nptl/pthread_rwlock_timedwrlock.c b/nptl/pthread_rwlock_timedwrlock.c
index 8eb31cf..5f2399f 100644
--- a/nptl/pthread_rwlock_timedwrlock.c
+++ b/nptl/pthread_rwlock_timedwrlock.c
@@ -1,4 +1,4 @@
-/* Copyright (C) 2003,2004,2007,2011 Free Software Foundation, Inc.
+/* Copyright (C) 2003-2012 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Martin Schwidefsky <schwidefsky@de.ibm.com>, 2003.
@@ -67,6 +67,16 @@ pthread_rwlock_timedwrlock (rwlock, abstime)
break;
}
+ /* Work around the fact that the kernel rejects negative timeout values
+ despite them being valid. */
+ if (__builtin_expect (abstime->tv_sec < 0, 0))
+ {
+ result = ETIMEDOUT;
+ break;
+ }
+
+#if (!defined __ASSUME_FUTEX_CLOCK_REALTIME \
+ || !defined lll_futex_timed_wait_bitset)
/* Get the current time. So far we support only one clock. */
struct timeval tv;
(void) gettimeofday (&tv, NULL);
@@ -86,6 +96,7 @@ pthread_rwlock_timedwrlock (rwlock, abstime)
result = ETIMEDOUT;
break;
}
+#endif
/* Remember that we are a writer. */
if (++rwlock->__data.__nr_writers_queued == 0)
@@ -102,8 +113,16 @@ pthread_rwlock_timedwrlock (rwlock, abstime)
lll_unlock (rwlock->__data.__lock, rwlock->__data.__shared);
/* Wait for the writer or reader(s) to finish. */
+#if (!defined __ASSUME_FUTEX_CLOCK_REALTIME \
+ || !defined lll_futex_timed_wait_bitset)
err = lll_futex_timed_wait (&rwlock->__data.__writer_wakeup,
waitval, &rt, rwlock->__data.__shared);
+#else
+ err = lll_futex_timed_wait_bitset (&rwlock->__data.__writer_wakeup,
+ waitval, abstime,
+ FUTEX_CLOCK_REALTIME,
+ rwlock->__data.__shared);
+#endif
/* Get the lock. */
lll_lock (rwlock->__data.__lock, rwlock->__data.__shared);
diff --git a/nptl/sysdeps/unix/sysv/linux/lowlevelrobustlock.c b/nptl/sysdeps/unix/sysv/linux/lowlevelrobustlock.c
index 7b4e843..9a9e673 100644
--- a/nptl/sysdeps/unix/sysv/linux/lowlevelrobustlock.c
+++ b/nptl/sysdeps/unix/sysv/linux/lowlevelrobustlock.c
@@ -1,4 +1,4 @@
-/* Copyright (C) 2006, 2007 Free Software Foundation, Inc.
+/* Copyright (C) 2006-2012 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Jakub Jelinek <jakub@redhat.com>, 2006.
@@ -70,8 +70,15 @@ __lll_robust_timedlock_wait (int *futex, const struct timespec *abstime,
if (oldval == 0)
goto try;
+ /* Work around the fact that the kernel rejects negative timeout values
+ despite them being valid. */
+ if (__builtin_expect (abstime->tv_sec < 0, 0))
+ return ETIMEDOUT;
+
do
{
+#if (!defined __ASSUME_FUTEX_CLOCK_REALTIME \
+ || !defined lll_futex_timed_wait_bitset)
struct timeval tv;
struct timespec rt;
@@ -90,6 +97,7 @@ __lll_robust_timedlock_wait (int *futex, const struct timespec *abstime,
/* Already timed out? */
if (rt.tv_sec < 0)
return ETIMEDOUT;
+#endif
/* Wait. */
if (__builtin_expect (oldval & FUTEX_OWNER_DIED, 0))
@@ -100,7 +108,13 @@ __lll_robust_timedlock_wait (int *futex, const struct timespec *abstime,
&& atomic_compare_and_exchange_bool_acq (futex, newval, oldval))
continue;
+#if (!defined __ASSUME_FUTEX_CLOCK_REALTIME \
+ || !defined lll_futex_timed_wait_bitset)
lll_futex_timed_wait (futex, newval, &rt, private);
+#else
+ lll_futex_timed_wait_bitset (futex, newval, abstime,
+ FUTEX_CLOCK_REALTIME, private);
+#endif
try:
;
diff --git a/nptl/sysdeps/unix/sysv/linux/powerpc/lowlevellock.h b/nptl/sysdeps/unix/sysv/linux/powerpc/lowlevellock.h
index 406c290..17e63c6 100644
--- a/nptl/sysdeps/unix/sysv/linux/powerpc/lowlevellock.h
+++ b/nptl/sysdeps/unix/sysv/linux/powerpc/lowlevellock.h
@@ -88,6 +88,19 @@
INTERNAL_SYSCALL_ERROR_P (__ret, __err) ? -__ret : __ret; \
})
+#define lll_futex_timed_wait_bitset(futexp, val, timespec, clockbit, private) \
+ ({ \
+ INTERNAL_SYSCALL_DECL (__err); \
+ long int __ret; \
+ int __op = FUTEX_WAIT_BITSET | clockbit; \
+ \
+ __ret = INTERNAL_SYSCALL (futex, __err, 6, (futexp), \
+ __lll_private_flag (__op, private), \
+ (val), (timespec), NULL /* Unused. */, \
+ FUTEX_BITSET_MATCH_ANY); \
+ INTERNAL_SYSCALL_ERROR_P (__ret, __err) ? -__ret : __ret; \
+ })
+
#define lll_futex_wake(futexp, nr, private) \
({ \
INTERNAL_SYSCALL_DECL (__err); \
diff --git a/nptl/sysdeps/unix/sysv/linux/s390/lowlevellock.h b/nptl/sysdeps/unix/sysv/linux/s390/lowlevellock.h
index 9709282..0b7110f 100644
--- a/nptl/sysdeps/unix/sysv/linux/s390/lowlevellock.h
+++ b/nptl/sysdeps/unix/sysv/linux/s390/lowlevellock.h
@@ -93,6 +93,26 @@
__result; \
})
+#define lll_futex_timed_wait_bitset(futexp, val, timespec, clockbit, private) \
+ ({ \
+ register unsigned long int __r2 asm ("2") = (unsigned long int) (futexp); \
+ register unsigned long int __r3 asm ("3") \
+ = __lll_private_flag ((FUTEX_WAIT_BITSET | clockbit), private); \
+ register unsigned long int __r4 asm ("4") = (long int) (val); \
+ register unsigned long int __r5 asm ("5") = (long int) (timespec); \
+ register unsigned long int __r6 asm ("6") = (unsigned long int) (NULL); \
+ register unsigned long int __r7 asm ("7") \
+ = (unsigned int) (FUTEX_BITSET_MATCH_ANY); \
+ register unsigned long __result asm ("2"); \
+ \
+ __asm __volatile ("svc %b1" \
+ : "=d" (__result) \
+ : "i" (SYS_futex), "0" (__r2), "d" (__r3), \
+ "d" (__r4), "d" (__r5), "d" (__r6), "d" (__r7) \
+ : "cc", "memory" ); \
+ __result; \
+ })
+
#define lll_futex_wake(futex, nr, private) \
({ \