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author | Siddhesh Poyarekar <siddhesh@redhat.com> | 2012-11-05 21:12:10 +0530 |
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committer | Siddhesh Poyarekar <siddhesh@redhat.com> | 2012-11-05 21:12:52 +0530 |
commit | 8f861542dd0603bef99e126e509ece89514c1eeb (patch) | |
tree | 083f3bd20edfa09a2341e0340013c0781b4696ad /nptl/sysdeps/unix/sysv/linux/lowlevelrobustlock.c | |
parent | 155ee340b875834693fbd1b7401af7fe88ace04d (diff) | |
download | glibc-8f861542dd0603bef99e126e509ece89514c1eeb.zip glibc-8f861542dd0603bef99e126e509ece89514c1eeb.tar.gz glibc-8f861542dd0603bef99e126e509ece89514c1eeb.tar.bz2 |
[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/sysdeps/unix/sysv/linux/lowlevelrobustlock.c')
-rw-r--r-- | nptl/sysdeps/unix/sysv/linux/lowlevelrobustlock.c | 16 |
1 files changed, 15 insertions, 1 deletions
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: ; |