2ae96e8ae8
Removed trailing white space at end of lines
2016-07-17 18:10:19 +02:00
3df541c0e6
ldd.1, localedef.1, add_key.2, chroot.2, clone.2, fork.2, futex.2, get_mempolicy.2, get_robust_list.2, getitimer.2, getpriority.2, ioctl.2, ioctl_ficlonerange.2, ioctl_fideduperange.2, kcmp.2, kill.2, lookup_dcookie.2, mmap.2, mount.2, open.2, pciconfig_read.2, perf_event_open.2, prctl.2, process_vm_readv.2, ptrace.2, quotactl.2, recv.2, setfsgid.2, setfsuid.2, sysinfo.2, umask.2, umount.2, unshare.2, utimensat.2, wait.2, assert.3, fmax.3, fmin.3, getauxval.3, inet_pton.3, malloc_hook.3, memmem.3, mkdtemp.3, mktemp.3, printf.3, strcasecmp.3, strcat.3, strtoul.3, strxfrm.3, console_codes.4, console_ioctl.4, lirc.4, tty.4, vcs.4, charmap.5, elf.5, locale.5, proc.5, repertoiremap.5, utmp.5, capabilities.7, cgroup_namespaces.7, cgroups.7, charsets.7, cp1251.7, cp1252.7, credentials.7, feature_test_macros.7, iso_8859-1.7, iso_8859-15.7, iso_8859-5.7, koi8-r.7, koi8-u.7, man-pages.7, mount_namespaces.7, namespaces.7, netlink.7, pid_namespaces.7, unix.7, user_namespaces.7, utf-8.7: tstamp
...
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2016-07-17 18:10:19 +02:00
c082f385d4
futex.2: srcfix
...
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2016-07-07 10:12:58 +02:00
4100abc52e
futex.2: Explain how to get equivalent of FUTEX_WAIT with an absolute timeout
...
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2016-06-26 11:25:22 +02:00
678c99868e
futex.2: Describe FUTEX_BITSET_MATCH_ANY
...
Describe FUTEX_BITSET_MATCH_ANY and FUTEX_WAIT and FUTEX_WAKE
equivalences.
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2016-06-26 11:25:11 +02:00
6c38ce7f1f
futex.2: Note that at least one bit must be set in mask for BITSET operations
...
At least one bit must be set in the 'val3' mask supplied for the
FUTEX_WAIT_BITSET and FUTEX_WAKE_BITSET operations.
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2016-06-24 09:42:15 +02:00
84abf4ba97
futex.2: wfix
...
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2016-06-24 09:34:16 +02:00
b3d5bc4ca6
futex.2: ffix
...
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2016-06-24 09:28:56 +02:00
ac991a11d7
futex.2: wfix
...
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2016-06-24 08:55:17 +02:00
a6918f1d4b
futex.2: wfix
...
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2016-06-24 08:54:03 +02:00
40d2dab928
futex.2: ffix
...
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2016-06-24 08:53:09 +02:00
6f19879d52
futex.2: wfix
...
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2016-06-24 08:53:09 +02:00
a01c3098e8
futex.2: Clarify clock default and choices for FUTEX_WAIT
...
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2016-06-24 08:53:09 +02:00
8064bfa536
futex.2: Fix descriptions of various timeouts
...
Reported-by: Thomas Gleixner <tglx@linutronix.de>
Reported-by: Darren Hart <dvhart@infradead.org>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2016-06-23 12:47:49 +02:00
017d194b0b
futex.2: Correct an ENOSYS error description
...
Since Linux 4.5, FUTEX_CLOCK_REALTIME is allowed with with FUTEX_WAIT.
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2016-06-23 12:47:41 +02:00
0b97369dd8
futex.2: Remove crufty text about FUTEX_WAIT_BITSET interpretation of timeout
...
Since Linux 4.5, FUTEX_WAIT also understands
FUTEX_CLOCK_REALTIME.
Reported-by: Darren Hart <dvhart@infradead.org>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2016-06-23 10:19:39 +02:00
979867082b
locale.1, localedef.1, _exit.2, accept.2, access.2, acct.2, adjtimex.2, bdflush.2, bind.2, bpf.2, brk.2, chdir.2, chmod.2, chown.2, chroot.2, clock_nanosleep.2, clone.2, close.2, connect.2, copy_file_range.2, create_module.2, delete_module.2, dup.2, epoll_ctl.2, eventfd.2, execve.2, fallocate.2, fanotify_init.2, fcntl.2, flock.2, fork.2, fsync.2, futex.2, get_kernel_syms.2, getdomainname.2, getgroups.2, gethostname.2, getpagesize.2, getpeername.2, getsid.2, getsockname.2, getsockopt.2, gettimeofday.2, init_module.2, ioctl.2, ioctl_list.2, ioperm.2, iopl.2, kexec_load.2, kill.2, killpg.2, link.2, listen.2, llseek.2, lseek.2, madvise.2, memfd_create.2, mincore.2, mkdir.2, mknod.2, mmap.2, mount.2, nanosleep.2, nice.2, open.2, personality.2, pipe.2, poll.2, posix_fadvise.2, read.2, readahead.2, readlink.2, readv.2, recv.2, recvmmsg.2, rename.2, request_key.2, sched_setaffinity.2, sched_setattr.2, select.2, select_tut.2, semctl.2, semop.2, send.2, sendfile.2, sendmmsg.2, seteuid.2, setns.2, setpgid.2, setreuid.2, shutdown.2, sigaction.2, sigaltstack.2, signal.2, signalfd.2, sigpending.2, sigprocmask.2, sigsuspend.2, socketpair.2, splice.2, stat.2, statfs.2, stime.2, symlink.2, sync.2, syscall.2, syscalls.2, times.2, truncate.2, unlink.2, unshare.2, uselib.2, utimensat.2, vfork.2, vhangup.2, wait.2, wait4.2, write.2, a64l.3, abs.3, acos.3, acosh.3, addseverity.3, adjtime.3, aio_read.3, aio_write.3, asin.3, asinh.3, atan.3, atan2.3, atanh.3, atoi.3, backtrace.3, cbrt.3, ceil.3, cfree.3, clearenv.3, clock_getcpuclockid.3, clog10.3, cmsg.3, copysign.3, cos.3, cosh.3, ctermid.3, ctime.3, daemon.3, dirfd.3, div.3, dl_iterate_phdr.3, drand48.3, drand48_r.3, dysize.3, ecvt.3, ecvt_r.3, endian.3, erf.3, erfc.3, errno.3, exec.3, exp.3, exp2.3, expm1.3, fabs.3, fdim.3, ferror.3, fexecve.3, ffs.3, fgetgrent.3, fgetpwent.3, finite.3, flockfile.3, floor.3, fma.3, fmax.3, fmin.3, fmod.3, fopen.3, fpclassify.3, frexp.3, fseeko.3, fts.3, futimes.3, fwide.3, gamma.3, gcvt.3, getaddrinfo.3, getcwd.3, getdate.3, getdirentries.3, getdtablesize.3, getgrent.3, getgrent_r.3, getgrnam.3, getgrouplist.3, gethostbyname.3, gethostid.3, getline.3, getloadavg.3, getmntent.3, getnameinfo.3, getnetent_r.3, getpass.3, getprotoent_r.3, getpwent.3, getpwent_r.3, getpwnam.3, getrpcent_r.3, getservent_r.3, getspnam.3, getsubopt.3, getusershell.3, getutent.3, getw.3, gsignal.3, hypot.3, ilogb.3, inet.3, initgroups.3, insque.3, isalpha.3, isgreater.3, iswblank.3, j0.3, ldexp.3, lgamma.3, lio_listio.3, lockf.3, log.3, log10.3, log1p.3, log2.3, logb.3, lrint.3, lround.3, makedev.3, matherr.3, mbsnrtowcs.3, mkdtemp.3, mkfifo.3, mkstemp.3, mktemp.3, modf.3, mq_close.3, mq_getattr.3, mq_notify.3, mq_receive.3, mq_send.3, nan.3, nextafter.3, on_exit.3, open_memstream.3, opendir.3, perror.3, popen.3, posix_fallocate.3, posix_madvise.3, posix_memalign.3, posix_openpt.3, posix_spawn.3, pow.3, printf.3, profil.3, psignal.3, pthread_attr_setstack.3, pthread_setaffinity_np.3, putenv.3, putpwent.3, qecvt.3, rand.3, random.3, random_r.3, rcmd.3, readdir.3, realpath.3, remainder.3, remquo.3, rexec.3, rint.3, round.3, rpc.3, rpmatch.3, scalb.3, scalbln.3, scandir.3, scanf.3, seekdir.3, sem_wait.3, setbuf.3, setenv.3, setjmp.3, setnetgrent.3, siginterrupt.3, signbit.3, significand.3, sigset.3, sigsetops.3, sigvec.3, sigwait.3, sin.3, sinh.3, sleep.3, sockatmark.3, sqrt.3, statvfs.3, stpcpy.3, stpncpy.3, strdup.3, strerror.3, strftime.3, strlen.3, strnlen.3, strsep.3, strsignal.3, strtod.3, strtok.3, strtol.3, strtoul.3, syslog.3, system.3, tan.3, tanh.3, telldir.3, tempnam.3, termios.3, tgamma.3, timegm.3, timeradd.3, tmpfile.3, tmpnam.3, toascii.3, trunc.3, ttyslot.3, tzset.3, ualarm.3, unlocked_stdio.3, usleep.3, wcpcpy.3, wcpncpy.3, wcscasecmp.3, wcsdup.3, wcsncasecmp.3, wcsnlen.3, wcsnrtombs.3, wprintf.3, y0.3, pts.4, st.4, tty_ioctl.4, elf.5, gai.conf.5, group.5, locale.5, nsswitch.conf.5, proc.5, utmp.5, aio.7, capabilities.7, credentials.7, environ.7, epoll.7, fanotify.7, feature_test_macros.7, inotify.7, ip.7, mq_overview.7, namespaces.7, pipe.7, signal.7, socket.7, standards.7, svipc.7, symlink.7, time.7, unicode.7, unix.7: tstamp
...
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2016-03-15 17:30:43 +13:00
949ceae398
futex.2: FUTEX_CLOCK_REALTIME can now be used with FUTEX_WAIT
...
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2016-03-15 13:28:53 +13:00
def04e1ccf
chown.2, futex.2, membarrier.2, memfd_create.2, mount.2, msgop.2, open.2, open_by_handle_at.2, perf_event_open.2, readv.2, sched_setscheduler.2, syslog.2, basename.3: ffix
...
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2016-02-03 08:46:16 +01:00
ed1819cf3e
futex.2: tfix
...
Signed-off-by: Jakub Wilk <jwilk@jwilk.net>
2016-02-03 08:27:03 +01:00
67c67ff26b
futex.2: tfix
...
Signed-off-by: Jakub Wilk <jwilk@jwilk.net>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2016-01-08 17:26:15 +01:00
f6615c426b
futex.2: tfix
...
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2015-12-30 20:35:30 +01:00
cd175805de
futex.2: srcfix
...
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2015-12-30 13:57:02 +01:00
e24fbf1098
Removed trailing white space at end of lines
2015-12-29 13:51:32 +01:00
29b41e747f
accept.2, acct.2, bind.2, clock_getres.2, connect.2, dup.2, epoll_create.2, eventfd.2, execve.2, fanotify_init.2, fcntl.2, fork.2, futex.2, get_robust_list.2, getcpu.2, getpeername.2, getrlimit.2, getsockname.2, getsockopt.2, gettimeofday.2, inotify_init.2, listen.2, membarrier.2, memfd_create.2, mlock.2, mmap.2, personality.2, pipe.2, poll.2, recv.2, send.2, sendfile.2, shmget.2, shutdown.2, sigreturn.2, socket.2, socketcall.2, socketpair.2, spu_create.2, swapon.2, time.2, timerfd_create.2, uselib.2, dlerror.3, dlopen.3, drand48.3, errno.3, fnmatch.3, getgrent.3, getgrnam.3, getlogin.3, getpwent.3, getpwnam.3, iconv.3, mq_open.3, opendir.3, random_r.3, sem_open.3, shm_open.3, tmpfile.3, tzset.3, random.4, fanotify.7, futex.7, vdso.7, ld.so.8: tstamp
...
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2015-12-29 13:48:42 +01:00
e258766bf4
accept.2, acct.2, epoll_create.2, execve.2, futex.2, inotify_init.2, mmap.2, open.2, pipe.2, shmget.2, socket.2, socketpair.2, spu_create.2, swapon.2, uselib.2, getgrent.3, getgrnam.3, getlogin.3, getpwent.3, getpwnam.3, mq_open.3, opendir.3, sem_open.3, shm_open.3, tmpfile.3, fanotify.7: ERRORS: standardize text for ENFILE error
...
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2015-12-27 17:10:23 +01:00
8adaf0a794
futex.2: Minor wording tweaks after comments from Darren Hart
...
Reported-by: Darren Hart <dvhart@infradead.org>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2015-12-26 09:02:35 +01:00
2af84f99ad
futex.2: wfix
...
Reported-by: Jonathan Wakely <jwakely@redhat.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2015-12-19 06:22:47 +01:00
bc54ed38c5
futex.2: Minor wording fixes
...
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2015-12-19 06:22:11 +01:00
5e1456d4c9
futex.2: Replace "bitset" by "bit mask"
...
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2015-12-19 06:22:02 +01:00
da894b18a8
futex.2: Fixes after comments from Darren Hart
...
Reported-by: Darren Hart <dvhart@infradead.org>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2015-12-17 06:43:53 +01:00
0fb87d16ac
futex.2: Clarify "total ordering" a little
...
Comments from Davidlohr:
So there are two things here regarding ordering. One is the
most obvious which is ordered due to the taking/dropping the
hb spinlock. Secondly, its the cases which Peter brought up
a while ago that involves atomic futex ops futex_atomic_*(),
which do not have clearly defined semantics, and you get
inconsistencies with certain archs (tile being the worst
iirc).
But anyway, the important thing users need to know about is
that the atomic futex operation must be totally ordered wrt
any other user tasks that are trying to access that address.
This is not necessarily the case for kernel ops. Peter
illustrates this nicely with lock stealing example; (see
https://lkml.org/lkml/2015/8/26/596 ).
Internally, I believe we decided that making it fully ordered
(as opposed to making use of implicit barriers for
ACQUIRE/RELEASE), so you'd end up having an MB ll/sc MB kind of
setup.
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
Reported-by: Davidlohr Bueso <dave@stgolabs.net>
2015-12-17 06:43:40 +01:00
3fbb1be115
futex.2: Minor fixes after comments from Torvald Riegel
...
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2015-12-15 17:00:04 +01:00
57f2d48bc1
futex.2: tfix
...
Reported-by: Alexander Monakov <amonakov@ispras.ru>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2015-12-15 16:47:52 +01:00
ee65b0e842
futex.2: srcfix (notes from conversation with tglx)
...
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2015-12-15 14:39:49 +01:00
c3f4c0196a
futex.2: tfix
...
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2015-12-15 14:39:49 +01:00
d0442d147d
futex.2: wfix
...
Reported-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2015-12-15 14:39:49 +01:00
1d09c1500f
futex.2: Fixes after feedback from Thomas Gleixner
...
Reported-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2015-12-15 14:39:49 +01:00
ca4e5b2b99
futex.2: Minor wording fixes
...
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2015-12-15 14:39:49 +01:00
601399f31f
futex.2: Improvements after comments from Darren Hart
...
Reported-by: Darren Hart <dvhart@infradead.org>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2015-12-15 14:39:49 +01:00
adc89a976e
futex.2: ffix
...
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2015-12-15 14:39:49 +01:00
41b6c6a080
futex.2: srcfix: FIXME
...
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2015-12-15 14:39:49 +01:00
c3875d1d3a
futex.2: Fixes after review comments from Thomas Gleixner
...
Reported-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2015-12-15 14:39:49 +01:00
30239c10a8
futex.2: Various fixes after comments from Thomas Gleixner
...
Reported-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2015-12-15 14:39:49 +01:00
aab5ca4b64
futex.2: wfix
...
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2015-12-15 14:39:49 +01:00
f0a9e8f4ce
futex.2: tfix
...
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2015-12-15 14:39:49 +01:00
39e9b2e1e4
futex.2: wfix
...
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2015-12-15 14:39:49 +01:00
9cee832c40
futex.2: wfix
...
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2015-12-15 14:39:49 +01:00
ac89487996
futex.2: Fixes after review comments from Thomas Gleixner
...
Reported-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2015-12-15 14:39:49 +01:00
dcb410c3c8
futex.2: tfix
...
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2015-12-15 14:39:49 +01:00
627b50ce7c
futex.2: Elaborate on why "requeue" operations can be preferable to FUTEX_WAKE
...
Cowritten-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2015-12-15 14:39:48 +01:00
8297383e9e
futex.2: Clean-ups and FIXME removeal after feedback from Thomas Gleixner
...
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2015-12-15 14:39:48 +01:00
27dd3a6e79
futex.2: Remove warning that FUTEX_REQUEUE is broken
...
Darren Hart pointed me to the comments from Rich Felker
that there are valid use cases for FUTEX_REQUEUE.
From: Rich Felker <dalias@libc.org>
Date: Wed, 29 Oct 2014 22:43:17 -0400
To: Darren Hart <dvhart@infradead.org>
Cc: GLIBC Devel <libc-alpha@sourceware.org>, ...
Subject: Re: Add futex wrapper to glibc?
On Wed, Oct 29, 2014 at 06:59:15PM -0700, Darren Hart wrote:
[...]
> I wonder though... can we not wrap FUTEX_REQUEUE? It's fundamentally
> broken. FUTEX_CMP_REQUEUE should *always* be used instead. The glibc
> wrapper is one way to encourage developers to do the right thing
> (don't expose the bad op in the header).
You're mistaken here. There are plenty of valid ways to use
FUTEX_REQUEUE - for example if the calling thread is requeuing the
target(s) to a lock that the calling thread owns. Just because it
doesn't meet the needs of the way glibc was using it internally
doesn't mean it's useless for other applications.
Reported-by: Darren Hart <dvhart@infradead.org>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2015-12-15 14:39:48 +01:00
da56650ae4
futex.2: srcfix
...
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2015-12-15 14:39:48 +01:00
fd1056148b
futex.2: Minor wording fixes
...
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2015-12-15 14:39:48 +01:00
55f9e85ead
futex.2: Minor wording fixes
...
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2015-12-15 14:39:48 +01:00
b0f35fbb09
futex.2: tfix
...
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2015-12-15 14:39:48 +01:00
c0dc758efd
futex.2: Rewrap some source lines (no content changes)
...
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2015-12-15 14:39:48 +01:00
9d32a39b82
futex.2: Minor wording fixes
...
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2015-12-15 14:39:48 +01:00
d45f244c6d
futex.2: Minor wording fixes
...
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2015-12-15 14:39:48 +01:00
7e8dcabcb1
futex.2: Reword paragraph describing futex word
...
Reported-by: Davidlohr Bueso <dave@stgolabs.net>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2015-12-15 14:39:48 +01:00
02f7b623c9
futex.2: NOTES: futexes are also used to implement read-write locks and barriers
...
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2015-12-15 14:39:48 +01:00
e0074751c9
futex.2: SEE ALSO: add pthread_mutexattr_getprotocol(3)
...
Reported-by: Davidlohr Bueso <dave@stgolabs.net>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2015-12-15 14:39:48 +01:00
36a90a75ce
futex.2: wfix
...
Reported-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2015-12-15 14:39:48 +01:00
d6bb5a38db
futex.2: Tidy up some FIXMEs
...
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2015-12-15 14:39:48 +01:00
cf44281c66
futex.2: Point out that futexes are used to implement higher-level abstractions
...
Reported-by: Thomas Gleixner <tglx@linutronix.de>
Reported-by: Torvald Riegel <triegel@redhat.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2015-12-15 14:39:48 +01:00
78bbcd9faf
futex.2: Remove an obsolete FIXME
...
Reviewed-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2015-12-15 14:39:48 +01:00
cabee29d5e
futex.2: tfix
...
Reported-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2015-12-15 14:39:48 +01:00
e61abc2018
futex.2: tfix
...
Reported-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2015-12-15 14:39:48 +01:00
a5c5a06aba
futex.2: Clarify return value details
...
Reporte-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2015-12-15 14:39:48 +01:00
943ccc5228
futex.2: Remove detail about kernel internals
...
As commented on by Davidlohr Bueso:
This to me reads a bit too much into the kernel (fastpath,
refcnt, vmas). Why not just mention that it avoids overhead
in the kernel or something? I don't recall any manpage
mentioning such details, but I could be wrong.
Reported-by: Davidlohr Bueso <dave@stgolabs.net>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2015-12-15 14:39:48 +01:00
10022b8e63
futex.2: Casting utime to uint32_t
...
The kernel uses the following cast:
if (cmd == FUTEX_REQUEUE || cmd == FUTEX_CMP_REQUEUE ||
cmd == FUTEX_CMP_REQUEUE_PI || cmd == FUTEX_WAKE_OP)
val2 = (u32) (unsigned long) utime;
This ensures that always the least significant four bytes of the
pointer are used, both on ILP32 and LP64 systems.
On a big endian system a simple cast from 64 bit pointer to 32 bit
integer would return the most significant four bytes.
We have to make the reader of the man-page aware of the usage
of the least significant bytes.
Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2015-12-15 14:39:48 +01:00
c6dc40a2c9
futex.2: Use known types
...
Type u32 is not exposed to the user. Instead, refer to uint32_t,
which is defined in ISO/IEC 9899:1999.
Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2015-12-15 14:39:48 +01:00
d725ab772e
futex.2: tfix
...
Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2015-12-15 14:39:48 +01:00
78e856927e
futex.2: wfix
...
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2015-12-15 14:39:48 +01:00
0c3ec26b07
futex.2: Minor wording fixes
...
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2015-12-15 14:39:48 +01:00
8e754e12c5
futex.2: explanation of blocking
...
Use shorter sentences.
Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2015-12-15 14:39:48 +01:00
b80daba225
futex.2: explanation of blocking behavior
...
Shorten overlong sentence.
Highlight futex().
Tfix.
Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2015-12-15 14:39:47 +01:00
344df36631
futex.2: clarify address mapping
...
Using the word "physical" address should make the text easier to
make.
Avoid negations like "may not be equal".
Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2015-12-15 14:39:47 +01:00
594536fb2c
futex.2: tfix
...
Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2015-12-15 14:39:47 +01:00
4c8cb0ffe6
futex.2: Rewrap some long source lines
...
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2015-12-15 14:39:47 +01:00
83e80dda44
futex.2: ffix
...
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2015-12-15 14:39:47 +01:00
63ad44cb92
futex.2: simplify example
...
Do not duplicate coding.
Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2015-12-15 14:39:47 +01:00
92a4669004
futex.2: futex.2: Fix error check in EXAMPLE: fork() fails with -1
...
Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2015-12-15 14:39:47 +01:00
357646628c
futex.2: tfix
...
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2015-12-15 14:39:47 +01:00
077981d467
futex.2: Wrap sentences at line boundaries
...
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2015-12-15 14:39:47 +01:00
74f58a643b
futex.2: Explicitly mark FIXMEs added by Torvald Riegel
...
Mainly so I can keep track of who said what should be fixed/checked
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2015-12-15 14:39:47 +01:00
4b35dc5dab
futex.2: Terminology fixes
...
Here is the result of a first pass over futex.2. I tried to
do nothing that is too controversial. I tried to apply the
terminology that at least Darren and I had in mind
consistently; but please check again.
The major changes are in how futexes are described in the
introductory parts of the page. I hope it's easier to understand
now. I've also tried to add some more precision to the the
description of the synchronization semantics (e.g., it makes a
difference whether we claim something is atomic (without further
qualification), or just atomic wrt. other futex operations).
In some cases, that adds some verbosity to the text -- but I
believe that this is worth the clarity and consistency in using
terms, for example.
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2015-12-15 14:39:47 +01:00
77da5febea
futex.2: tfix
...
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2015-12-15 14:39:47 +01:00
305cc4153b
futex.2: Add EXAMPLE program
...
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2015-12-15 14:39:47 +01:00
02182e7c8c
futex.2: srcfix: FIXME
...
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2015-12-15 14:39:47 +01:00
1af427a43d
futex.2: srcfix
...
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2015-12-15 14:39:47 +01:00
47f5c4baf5
futex.2: srcfix: FIXME
...
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2015-12-15 14:39:47 +01:00
f529fd2013
futex Since Linux 2.6.22, EINTR can no longer occur on spurious wakeup
...
As reported by Rich Felker:
I see no code in the kernel whereby a "spurious wakeup",
or anything other than interruption by a signal handler
that's not SA_RESTART, can cause futex to fail with EINTR.
In general, overloading of EINTR and/or spurious EINTRs
from a syscall make it impossible to use that syscall for
implementing any function where EINTR is a mandatory
failure on interruption-by-signal, since there is no way
for userspace to distinguish whether the EINTR occurred
as a result of an interrupting signal or some other
reason. The kernel folks have gone to great lengths to fix
spurious EINTRs (see signal(7) for history), especially by
non-interrupting signal handlers, including in futex, and
allowing EINTR here would be contrary to that goal.
It's my belief that the "or a spurious wakeup" text should
simply be removed.
The reason I'm raising this topic is its relevance to a
thread on libc-alpha:
[RFC] mutex destruction (#13690 ): problem description and workarounds
The bug and mailing list discussions to which Rich refers are:
https://sourceware.org/bugzilla/show_bug.cgi?id=13690
https://sourceware.org/ml/libc-alpha/2014-12/threads.html#0001
Torvald Riegel also reported the same issue, and Thomas Gleixner
noted that the "EINTR on spurious wakeup" behavior went away in
Linux 2.6.22. See the LKML thread, "futex() man page update help
request", Jan 2015:
http://thread.gmane.org/gmane.linux.kernel/1703405/focus=7734
Reported-by: Rich Felker <dalias@libc.org>
Reported-by: Torvald Riegel <triegel@redhat.com>
Reported-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Michael Kerrisk <mtknpages@gmail.com>
2015-12-15 14:39:47 +01:00
9732dd8b3f
futex.2: Various fixes after review from Davidlohr Bueso
...
Reviewed-by: Davidlohr Bueso <dave@stgolabs.net>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2015-12-15 14:39:47 +01:00
2abcba676a
futex.2: Remove FUTEX_REQUEUE EINVAL error case
...
Thomas Gleixner confirmed my reading that this case does
not apply.
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2015-12-15 14:39:47 +01:00
9e2b90ee42
futex.2: Add an attmpt at a defintion of PI-aware futexes
...
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2015-12-15 14:39:47 +01:00
7bd3ffbc52
futex.2: srcfix
...
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2015-12-15 14:39:47 +01:00
d9d5be6bea
futex.2: tfix
...
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2015-12-15 14:39:46 +01:00
809ca3ae64
futex.2: Note that the kernel only "knows" about a futex in the contended case
...
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2015-12-15 14:39:46 +01:00
Michael Kerrisk