2015-12-13 13:17:43 +00:00
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.\" Copyright 2015 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
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.\"
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.\" %%%LICENSE_START(VERBATIM)
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.\" Permission is granted to make and distribute verbatim copies of this
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.\" manual provided the copyright notice and this permission notice are
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.\" Permission is granted to copy and distribute modified versions of this
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.\" manual under the conditions for verbatim copying, provided that the
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.\" entire resulting derived work is distributed under the terms of a
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.\" permission notice identical to this one.
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.\"
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.\" Since the Linux kernel and libraries are constantly changing, this
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.\" manual page may be incorrect or out-of-date. The author(s) assume no
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.\" responsibility for errors or omissions, or for damages resulting from
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.\" the use of the information contained herein. The author(s) may not
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.\" have taken the same level of care in the production of this manual,
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.\" which is licensed free of charge, as they might when working
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.\" %%%LICENSE_END
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.\"
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iconv.1, ldd.1, locale.1, localedef.1, memusage.1, memusagestat.1, mtrace.1, pldd.1, sprof.1, time.1, _syscall.2, add_key.2, alloc_hugepages.2, arch_prctl.2, bpf.2, cacheflush.2, capget.2, chdir.2, chmod.2, chown.2, chroot.2, clock_getres.2, clock_nanosleep.2, clone.2, close.2, connect.2, copy_file_range.2, create_module.2, delete_module.2, dup.2, epoll_create.2, epoll_ctl.2, epoll_wait.2, eventfd.2, execve.2, execveat.2, fallocate.2, fanotify_init.2, fcntl.2, flock.2, fork.2, fsync.2, futex.2, futimesat.2, get_kernel_syms.2, get_mempolicy.2, get_robust_list.2, getcpu.2, getdents.2, getdomainname.2, getgid.2, getgroups.2, gethostname.2, getitimer.2, getpagesize.2, getpeername.2, getpriority.2, getrandom.2, getresuid.2, getrlimit.2, getrusage.2, getsid.2, getsockname.2, getsockopt.2, gettid.2, gettimeofday.2, getuid.2, getunwind.2, init_module.2, inotify_add_watch.2, inotify_init.2, inotify_rm_watch.2, intro.2, io_cancel.2, io_destroy.2, io_getevents.2, io_setup.2, io_submit.2, ioctl_console.2, ioctl_fat.2, ioctl_ficlonerange.2, ioctl_fideduperange.2, ioctl_getfsmap.2, ioctl_iflags.2, ioctl_list.2, ioctl_ns.2, ioctl_tty.2, ioctl_userfaultfd.2, ioperm.2, iopl.2, ioprio_set.2, ipc.2, kcmp.2, kexec_load.2, keyctl.2, kill.2, link.2, listen.2, listxattr.2, llseek.2, lookup_dcookie.2, lseek.2, madvise.2, mbind.2, membarrier.2, memfd_create.2, migrate_pages.2, mincore.2, mkdir.2, mknod.2, mlock.2, mmap.2, mmap2.2, modify_ldt.2, move_pages.2, mprotect.2, mq_getsetattr.2, mremap.2, msgctl.2, msgget.2, msgop.2, msync.2, nanosleep.2, nfsservctl.2, nice.2, open.2, open_by_handle_at.2, outb.2, perf_event_open.2, perfmonctl.2, personality.2, pivot_root.2, pkey_alloc.2, poll.2, posix_fadvise.2, prctl.2, pread.2, process_vm_readv.2, ptrace.2, query_module.2, quotactl.2, read.2, readahead.2, readdir.2, readlink.2, readv.2, reboot.2, recv.2, recvmmsg.2, remap_file_pages.2, rename.2, request_key.2, restart_syscall.2, rt_sigqueueinfo.2, s390_pci_mmio_write.2, s390_runtime_instr.2, sched_get_priority_max.2, sched_rr_get_interval.2, sched_setaffinity.2, sched_setattr.2, sched_setparam.2, sched_setscheduler.2, sched_yield.2, seccomp.2, select.2, select_tut.2, semctl.2, semget.2, semop.2, send.2, sendfile.2, sendmmsg.2, set_mempolicy.2, set_thread_area.2, set_tid_address.2, seteuid.2, setfsgid.2, setfsuid.2, setgid.2, setns.2, setpgid.2, setresuid.2, setreuid.2, setsid.2, setuid.2, sgetmask.2, shmctl.2, shmget.2, shmop.2, sigaction.2, sigaltstack.2, signal.2, sigpending.2, sigprocmask.2, sigreturn.2, sigsuspend.2, sigwaitinfo.2, socket.2, socketcall.2, socketpair.2, splice.2, spu_create.2, spu_run.2, stat.2, statfs.2, statx.2, subpage_prot.2, swapon.2, symlink.2, sync.2, sync_file_range.2, syscall.2, syscalls.2, sysctl.2, sysfs.2, sysinfo.2, syslog.2, tee.2, time.2, timer_create.2, timer_getoverrun.2, timer_settime.2, timerfd_create.2, times.2, tkill.2, truncate.2, umask.2, umount.2, uname.2, unimplemented.2, unlink.2, unshare.2, uselib.2, userfaultfd.2, ustat.2, utime.2, utimensat.2, vfork.2, vmsplice.2, wait.2, wait4.2, write.2, CPU_SET.3, INFINITY.3, __ppc_get_timebase.3, __ppc_set_ppr_med.3, __ppc_yield.3, __setfpucw.3, acos.3, acosh.3, adjtime.3, aio_fsync.3, aio_init.3, aio_read.3, aio_return.3, aio_suspend.3, aio_write.3, alloca.3, argz_add.3, asin.3, asinh.3, asprintf.3, assert.3, assert_perror.3, atan.3, atan2.3, atanh.3, atexit.3, backtrace.3, basename.3, bindresvport.3, bsd_signal.3, bsearch.3, bswap.3, btree.3, byteorder.3, bzero.3, canonicalize_file_name.3, carg.3, cbrt.3, ccos.3, ccosh.3, ceil.3, cexp.3, cfree.3, clearenv.3, clock.3, clock_getcpuclockid.3, clog.3, clog10.3, clog2.3, cmsg.3, confstr.3, copysign.3, cos.3, cosh.3, crypt.3, csin.3, csinh.3, csqrt.3, ctan.3, ctanh.3, ctime.3, dbopen.3, dl_iterate_phdr.3, dladdr.3, dlerror.3, dlinfo.3, dlopen.3, dlsym.3, drand48.3, drand48_r.3, duplocale.3, encrypt.3, end.3, endian.3, envz_add.3, erf.3, erfc.3, err.3, errno.3, error.3, ether_aton.3, euidaccess.3, exec.3, exit.3, exp.3, exp10.3, exp2.3, expm1.3, fabs.3, fcloseall.3, fdim.3, fenv.3, ferror.3, fexecve.3, fflush.3, ffs.3, fgetc.3, fgetgrent.3, fgetpwent.3, finite.3, floor.3, fma.3, fmax.3, fmemopen.3, fmin.3, fmod.3, fmtmsg.3, fopen.3, fopencookie.3, fpclassify.3, fpurge.3, fputwc.3, fputws.3, frexp.3, fseek.3, fseeko.3, ftime.3, fts.3, ftw.3, futimes.3, gamma.3, gcvt.3, get_nprocs_conf.3, get_phys_pages.3, getaddrinfo.3, getaddrinfo_a.3, getauxval.3, getcontext.3, getcwd.3, getdate.3, getentropy.3, getenv.3, getfsent.3, getgrent.3, getgrent_r.3, getgrnam.3, getgrouplist.3, gethostbyname.3, gethostid.3, getifaddrs.3, getipnodebyname.3, getline.3, getlogin.3, getmntent.3, getnameinfo.3, getnetent.3, getnetent_r.3, getopt.3, getprotoent.3, getprotoent_r.3, getpw.3, getpwent.3, getpwent_r.3, getpwnam.3, getrpcent.3, getrpcent_r.3, getrpcport.3, gets.3, getservent.3, getservent_r.3, getspnam.3, getsubopt.3, getttyent.3, getumask.3, getutent.3, getwchar.3, glob.3, gnu_get_libc_version.3, grantpt.3, gsignal.3, hash.3, hsearch.3, hypot.3, iconv.3, iconv_close.3, iconv_open.3, if_nameindex.3, if_nametoindex.3, ilogb.3, inet.3, inet_net_pton.3, inet_ntop.3, inet_pton.3, initgroups.3, insque.3, intro.3, isalpha.3, isgreater.3, j0.3, key_setsecret.3, killpg.3, ldexp.3, lgamma.3, lio_listio.3, lockf.3, log.3, log10.3, log1p.3, log2.3, logb.3, login.3, lrint.3, lround.3, lsearch.3, lseek64.3, makecontext.3, makedev.3, mallinfo.3, malloc.3, malloc_get_state.3, malloc_info.3, malloc_stats.3, malloc_trim.3, malloc_usable_size.3, mallopt.3, matherr.3, mbsnrtowcs.3, mbsrtowcs.3, mbstowcs.3, mcheck.3, memccpy.3, memchr.3, memcmp.3, memcpy.3, mkfifo.3, mkstemp.3, mktemp.3, modf.3, mpool.3, mq_close.3, mq_getattr.3, mq_notify.3, mq_open.3, mq_receive.3, mq_send.3, mtrace.3, newlocale.3, nextafter.3, nextup.3, nl_langinfo.3, ntp_gettime.3, offsetof.3, on_exit.3, open_memstream.3, opendir.3, openpty.3, perror.3, popen.3, posix_fallocate.3, posix_madvise.3, posix_memalign.3, posix_openpt.3, posix_spawn.3, pow.3, pow10.3, printf.3, profil.3, program_invocation_name.3, psignal.3, pthread_atfork.3, pthread_attr_init.3, pthread_attr_setaffinity_np.3, pthread_attr_setdetachstate.3, pthread_attr_setguardsize.3, pthread_attr_setinheritsched.3, pthread_attr_setschedparam.3, pthread_attr_setschedpolicy.3, pthread_attr_setscope.3, pthread_attr_setstack.3, pthread_attr_setstackaddr.3, pthread_attr_setstacksize.3, pthread_cancel.3, pthread_cleanup_push.3, pthread_cleanup_push_defer_np.3, pthread_create.3, pthread_detach.3, pthread_exit.3, pthread_getattr_default_np.3, pthread_getattr_np.3, pthread_getcpuclockid.3, pthread_join.3, pthread_kill.3, pthread_kill_other_threads_np.3, pthread_self.3, pthread_setaffinity_np.3, pthread_setcancelstate.3, pthread_setconcurrency.3, pthread_setname_np.3, pthread_setschedparam.3, pthread_sigmask.3, pthread_sigqueue.3, pthread_testcancel.3, pthread_tryjoin_np.3, ptsname.3, putgrent.3, putpwent.3, qsort.3, random.3, random_r.3, rcmd.3, re_comp.3, readdir.3, realpath.3, recno.3, regex.3, remainder.3, remove.3, remquo.3, resolver.3, rexec.3, rint.3, round.3, rpc.3, rpmatch.3, rtime.3, scalb.3, scalbln.3, scandir.3, scanf.3, sched_getcpu.3, sem_close.3, sem_destroy.3, sem_getvalue.3, sem_init.3, sem_open.3, sem_wait.3, setaliasent.3, setbuf.3, setenv.3, setlocale.3, setlogmask.3, setnetgrent.3, shm_open.3, signbit.3, significand.3, sigpause.3, sigqueue.3, sigset.3, sigvec.3, sin.3, sincos.3, sinh.3, sleep.3, sockatmark.3, sqrt.3, statvfs.3, stdarg.3, stdin.3, strcasecmp.3, strcat.3, strchr.3, strcoll.3, strcpy.3, strdup.3, strerror.3, strfmon.3, strfromd.3, strftime.3, strptime.3, strsignal.3, strstr.3, strtod.3, strtok.3, strtol.3, strtoul.3, strverscmp.3, syslog.3, system.3, sysv_signal.3, tan.3, tanh.3, telldir.3, tempnam.3, termios.3, tgamma.3, timeradd.3, tmpnam.3, toupper.3, towlower.3, towupper.3, trunc.3, ttyslot.3, tzset.3, ualarm.3, ulimit.3, undocumented.3, unlocked_stdio.3, updwtmp.3, uselocale.3, usleep.3, wcrtomb.3, wcsdup.3, wcsnrtombs.3, wcsrtombs.3, wcstombs.3, wctob.3, wcwidth.3, wordexp.3, wprintf.3, xcrypt.3, xdr.3, y0.3, cciss.4, console_codes.4, dsp56k.4, fuse.4, hd.4, hpsa.4, initrd.4, intro.4, loop.4, random.4, rtc.4, sd.4, sk98lin.4, st.4, wavelan.4, acct.5, core.5, elf.5, filesystems.5, host.conf.5, hosts.5, locale.5, nologin.5, proc.5, resolv.conf.5, rpc.5, slabinfo.5, utmp.5, aio.7, arp.7, bootparam.7, capabilities.7, cgroup_namespaces.7, cgroups.7, charsets.7, cpuset.7, ddp.7, environ.7, epoll.7, fanotify.7, feature_test_macros.7, futex.7, inode.7, inotify.7, ip.7, ipv6.7, keyrings.7, locale.7, man-pages.7, man.7, math_error.7, mount_namespaces.7, mq_overview.7, namespaces.7, netdevice.7, netlink.7, packet.7, pipe.7, pkeys.7, pthreads.7, pty.7, raw.7, rtld-audit.7, rtnetlink.7, sched.7, session-keyring.7, signal.7, sock_diag.7, socket.7, spufs.7, suffixes.7, tcp.7, udp.7, udplite.7, unicode.7, units.7, unix.7, uri.7, user_namespaces.7, vdso.7, x25.7, xattr.7, iconvconfig.8, ld.so.8, ldconfig.8, sln.8: Update timestamps
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2017-09-15 10:44:56 +00:00
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.TH MEMBARRIER 2 2017-09-15 "Linux" "Linux Programmer's Manual"
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2015-12-13 13:17:43 +00:00
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.SH NAME
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membarrier \- issue memory barriers on a set of threads
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.SH SYNOPSIS
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.B #include <linux/membarrier.h>
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_exit.2, bpf.2, cacheflush.2, capget.2, chdir.2, chmod.2, chroot.2, clock_getres.2, clock_nanosleep.2, close.2, connect.2, create_module.2, dup.2, epoll_create.2, epoll_ctl.2, epoll_wait.2, eventfd.2, execve.2, execveat.2, exit_group.2, fanotify_mark.2, flock.2, fork.2, fsync.2, futex.2, futimesat.2, get_kernel_syms.2, get_mempolicy.2, get_robust_list.2, getcpu.2, getdomainname.2, getgid.2, getgroups.2, gethostname.2, getitimer.2, getpagesize.2, getpeername.2, getpid.2, getpriority.2, getrandom.2, getresuid.2, getrlimit.2, getrusage.2, getsid.2, getsockname.2, getsockopt.2, gettid.2, gettimeofday.2, getuid.2, getunwind.2, getxattr.2, idle.2, inotify_add_watch.2, inotify_init.2, inotify_rm_watch.2, ioctl.2, ioctl_fat.2, ioctl_ficlonerange.2, ioctl_fideduperange.2, ioctl_getfsmap.2, ioctl_tty.2, ioperm.2, iopl.2, keyctl.2, kill.2, link.2, listen.2, listxattr.2, llseek.2, lseek.2, madvise.2, mbind.2, membarrier.2, memfd_create.2, migrate_pages.2, mincore.2, mkdir.2, mknod.2, mlock.2, mmap.2, mmap2.2, modify_ldt.2, mount.2, move_pages.2, mprotect.2, mq_getsetattr.2, mremap.2, msgop.2, msync.2, nanosleep.2, nfsservctl.2, nice.2, pause.2, pciconfig_read.2, perf_event_open.2, perfmonctl.2, personality.2, pkey_alloc.2, poll.2, posix_fadvise.2, prctl.2, pread.2, process_vm_readv.2, ptrace.2, query_module.2, read.2, readahead.2, readdir.2, readv.2, reboot.2, recv.2, remap_file_pages.2, removexattr.2, rename.2, request_key.2, rmdir.2, rt_sigqueueinfo.2, sched_get_priority_max.2, sched_rr_get_interval.2, sched_setaffinity.2, sched_setparam.2, sched_setscheduler.2, sched_yield.2, select.2, select_tut.2, semctl.2, semget.2, semop.2, send.2, sendfile.2, set_mempolicy.2, set_tid_address.2, seteuid.2, setfsgid.2, setfsuid.2, setgid.2, setns.2, setpgid.2, setresuid.2, setreuid.2, setsid.2, setuid.2, setup.2, setxattr.2, sgetmask.2, shmctl.2, shmget.2, shutdown.2, sigaction.2, sigaltstack.2, sigpending.2, sigprocmask.2, sigsuspend.2, sigwaitinfo.2, socket.2, socketcall.2, socketpair.2, stat.2, statfs.2, stime.2, swapon.2, symlink.2, sync.2, sysctl.2, sysinfo.2, syslog.2, time.2, timer_create.2, timer_delete.2, timer_getoverrun.2, timer_settime.2, timerfd_create.2, times.2, tkill.2, truncate.2, umask.2, umount.2, uname.2, unlink.2, unshare.2, uselib.2, userfaultfd.2, ustat.2, utime.2, utimensat.2, vfork.2, vhangup.2, vm86.2, wait.2, wait4.2, write.2, CPU_SET.3, INFINITY.3, __ppc_get_timebase.3, __ppc_set_ppr_med.3, __ppc_yield.3, __setfpucw.3, a64l.3, abort.3, abs.3, acos.3, acosh.3, addseverity.3, adjtime.3, aio_cancel.3, aio_error.3, aio_fsync.3, aio_init.3, aio_read.3, aio_return.3, aio_suspend.3, aio_write.3, alloca.3, argz_add.3, asin.3, asinh.3, asprintf.3, assert.3, assert_perror.3, atan.3, atan2.3, atanh.3, atexit.3, atof.3, atoi.3, basename.3, bcmp.3, bcopy.3, bsd_signal.3, bsearch.3, bstring.3, btowc.3, byteorder.3, cabs.3, cacos.3, cacosh.3, canonicalize_file_name.3, carg.3, casin.3, casinh.3, catan.3, catanh.3, catopen.3, cbrt.3, ccos.3, ccosh.3, ceil.3, cexp.3, cexp2.3, cfree.3, cimag.3, clearenv.3, clock.3, clock_getcpuclockid.3, clog.3, clog10.3, clog2.3, closedir.3, cmsg.3, confstr.3, conj.3, copysign.3, cos.3, cosh.3, cpow.3, cproj.3, creal.3, crypt.3, csin.3, csinh.3, csqrt.3, ctan.3, ctanh.3, ctermid.3, ctime.3, daemon.3, difftime.3, dirfd.3, div.3, dlerror.3, dlopen.3, dlsym.3, drand48.3, drand48_r.3, duplocale.3, dysize.3, ecvt.3, ecvt_r.3, encrypt.3, endian.3, erf.3, erfc.3, err.3, errno.3, ether_aton.3, euidaccess.3, exec.3, exit.3, exp.3, exp10.3, exp2.3, expm1.3, fabs.3, fclose.3, fcloseall.3, fdim.3, fenv.3, ferror.3, fexecve.3, fflush.3, ffs.3, fgetc.3, fgetgrent.3, fgetpwent.3, fgetwc.3, fgetws.3, finite.3, flockfile.3, floor.3, fma.3, fmax.3, fmemopen.3, fmin.3, fmod.3, fmtmsg.3, fnmatch.3, fopen.3, fpathconf.3, fpclassify.3, fpurge.3, fputwc.3, fputws.3, fread.3, frexp.3, fseek.3, fseeko.3, ftime.3, ftok.3, fts.3, ftw.3, futimes.3, fwide.3, gamma.3, gcvt.3, get_nprocs_conf.3, get_phys_pages.3, getaddrinfo.3, getaddrinfo_a.3, getauxval.3, getcontext.3, getcwd.3, getdate.3, getdirentries.3, getdtablesize.3, getentropy.3, getenv.3, getfsent.3, getgrent.3, getgrent_r.3, getgrnam.3, getgrouplist.3, gethostbyname.3, gethostid.3, getifaddrs.3, getipnodebyname.3, getline.3, getloadavg.3, getlogin.3, getmntent.3, getnameinfo.3, getnetent.3, getnetent_r.3, getopt.3, getpass.3, getprotoent.3, getprotoent_r.3, getpt.3, getpw.3, getpwent.3, getpwent_r.3, getpwnam.3, getrpcent_r.3, getrpcport.3, gets.3, getservent.3, getservent_r.3, getspnam.3, getsubopt.3, getttyent.3, getumask.3, getusershell.3, getutent.3, getw.3, getwchar.3, glob.3, grantpt.3, group_member.3, gsignal.3, hsearch.3, hypot.3, iconv.3, iconv_close.3, iconv_open.3, if_nameindex.3, if_nametoindex.3, ilogb.3, index.3, inet.3, inet_net_pton.3, inet_ntop.3, infnan.3, initgroups.3, insque.3, isalpha.3, isatty.3, isfdtype.3, isgreater.3, iswalnum.3, iswalpha.3, iswblank.3, iswcntrl.3, iswctype.3, iswdigit.3, iswgraph.3, iswlower.3, iswprint.3, iswpunct.3, iswspace.3, iswupper.3, iswxdigit.3, j0.3, key_setsecret.3, killpg.3, ldexp.3, lgamma.3, localeconv.3, lockf.3, log.3, log10.3, log1p.3, log2.3, logb.3, login.3, lrint.3, lround.3, lsearch.3, lseek64.3, makecontext.3, malloc.3, malloc_get_state.3, malloc_hook.3, malloc_info.3, matherr.3, mblen.3, mbrlen.3, mbrtowc.3, mbsinit.3, mbsnrtowcs.3, mbsrtowcs.3, mbstowcs.3, mbtowc.3, mcheck.3, memccpy.3, memchr.3, memcmp.3, memcpy.3, memfrob.3, memmem.3, memmove.3, mempcpy.3, memset.3, mkdtemp.3, mkfifo.3, mkstemp.3, mktemp.3, modf.3, mpool.3, mq_close.3, mq_getattr.3, mq_notify.3, mq_open.3, mq_receive.3, mq_send.3, mq_unlink.3, mtrace.3, nan.3, netlink.3, newlocale.3, nextafter.3, nl_langinfo.3, offsetof.3, on_exit.3, open_memstream.3, opendir.3, openpty.3, perror.3, popen.3, posix_fallocate.3, posix_madvise.3, posix_memalign.3, posix_openpt.3, pow.3, pow10.3, printf.3, profil.3, psignal.3, pthread_atfork.3, pthread_attr_init.3, pthread_attr_setaffinity_np.3, pthread_attr_setdetachstate.3, pthread_attr_setguardsize.3, pthread_attr_setinheritsched.3, pthread_attr_setschedparam.3, pthread_attr_setschedpolicy.3, pthread_attr_setscope.3, pthread_attr_setstack.3, pthread_attr_setstackaddr.3, pthread_attr_setstacksize.3, pthread_cancel.3, pthread_cleanup_push.3, pthread_cleanup_push_defer_np.3, pthread_create.3, pthread_detach.3, pthread_equal.3, pthread_exit.3, pthread_getattr_default_np.3, pthread_getattr_np.3, pthread_getcpuclockid.3, pthread_join.3, pthread_kill.3, pthread_rwlockattr_setkind_np.3, pthread_self.3, pthread_setaffinity_np.3, pthread_setcancelstate.3, pthread_setconcurrency.3, pthread_setname_np.3, pthread_setschedparam.3, pthread_setschedprio.3, pthread_sigmask.3, pthread_sigqueue.3, pthread_testcancel.3, pthread_tryjoin_np.3, pthread_yield.3, ptsname.3, putenv.3, putgrent.3, putpwent.3, puts.3, putwchar.3, qecvt.3, qsort.3, raise.3, rand.3, random.3, random_r.3, rcmd.3, re_comp.3, readdir.3, realpath.3, remainder.3, remove.3, remquo.3, resolver.3, rewinddir.3, rexec.3, rint.3, round.3, rpmatch.3, rtime.3, rtnetlink.3, scalb.3, scalbln.3, scandir.3, scanf.3, sched_getcpu.3, seekdir.3, sem_close.3, sem_destroy.3, sem_getvalue.3, sem_init.3, sem_open.3, sem_post.3, sem_unlink.3, sem_wait.3, setaliasent.3, setbuf.3, setenv.3, setlocale.3, setlogmask.3, setnetgrent.3, shm_open.3, siginterrupt.3, signbit.3, significand.3, sigpause.3, sigqueue.3, sigset.3, sigvec.3, sigwait.3, sin.3, sincos.3, sinh.3, sleep.3, sockatmark.3, sqrt.3, statvfs.3, stdarg.3, stdio.3, stdio_ext.3, stpcpy.3, stpncpy.3, strcasecmp.3, strcat.3, strchr.3, strcmp.3, strcoll.3, strcpy.3, strdup.3, strerror.3, strfmon.3, strfromd.3, strfry.3, strftime.3, strlen.3, strnlen.3, strpbrk.3, strptime.3, strsep.3, strsignal.3, strspn.3, strstr.3, strtod.3, strtoimax.3, strtok.3, strtol.3, strtoul.3, strverscmp.3, strxfrm.3, swab.3, sysconf.3, syslog.3, system.3, sysv_signal.3, tan.3, tanh.3, tcgetpgrp.3, tcgetsid.3, telldir.3, tempnam.3, termios.3, tgamma.3, timegm.3, timeradd.3, tmpfile.3, tmpnam.3, toascii.3, toupper.3, towctrans.3, towlower.3, towupper.3, trunc.3, tsearch.3, ttyname.3, ttyslot.3, tzset.3, ualarm.3, ulimit.3, ungetwc.3, unlocked_stdio.3, unlockpt.3, updwtmp.3, uselocale.3, usleep.3, wcpcpy.3, wcpncpy.3, wcrtomb.3, wcscasecmp.3, wcscat.3, wcschr.3, wcscmp.3, wcscpy.3, wcscspn.3, wcsdup.3, wcslen.3, wcsncasecmp.3, wcsncat.3, wcsncmp.3, wcsncpy.3, wcsnlen.3, wcsnrtombs.3, wcspbrk.3, wcsrchr.3, wcsrtombs.3, wcsspn.3, wcsstr.3, wcstoimax.3, wcstok.3, wcstombs.3, wcswidth.3, wctob.3, wctomb.3, wctrans.3, wctype.3, wcwidth.3, wmemchr.3, wmemcmp.3, wmemcpy.3, wmemmove.3, wmemset.3, wordexp.3, wprintf.3, xcrypt.3, y0.3, dsp56k.4, random.4, rtc.4, st.4, ddp.7, ip.7, ipv6.7, packet.7, rtnetlink.7, socket.7, tcp.7, udp.7, udplite.7, x25.7: ffix
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2017-08-15 15:16:29 +00:00
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.PP
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2015-12-13 13:17:43 +00:00
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.BI "int membarrier(int " cmd ", int " flags ");
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.SH DESCRIPTION
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2015-12-15 14:53:49 +00:00
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The
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.BR membarrier ()
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system call helps reducing the overhead of the memory barrier
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2015-12-13 13:17:43 +00:00
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instructions required to order memory accesses on multi-core systems.
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However, this system call is heavier than a memory barrier, so using it
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effectively is
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2015-12-15 14:53:49 +00:00
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.I not
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2015-12-13 13:17:43 +00:00
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as simple as replacing memory barriers with this
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2015-12-15 14:53:49 +00:00
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system call, but requires understanding of the details below.
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_syscall.2, bpf.2, cacheflush.2, capget.2, chdir.2, chmod.2, chroot.2, clock_getres.2, clock_nanosleep.2, clone.2, close.2, connect.2, copy_file_range.2, create_module.2, delete_module.2, dup.2, epoll_create.2, epoll_ctl.2, epoll_wait.2, eventfd.2, execve.2, execveat.2, fallocate.2, flock.2, fork.2, fsync.2, futex.2, futimesat.2, get_kernel_syms.2, get_mempolicy.2, get_robust_list.2, getcpu.2, getdents.2, getdomainname.2, getgid.2, getgroups.2, gethostname.2, getitimer.2, getpagesize.2, getpeername.2, getpriority.2, getrandom.2, getresuid.2, getrlimit.2, getrusage.2, getsid.2, getsockname.2, getsockopt.2, gettid.2, gettimeofday.2, getuid.2, getunwind.2, init_module.2, inotify_add_watch.2, inotify_init.2, inotify_rm_watch.2, intro.2, io_cancel.2, io_destroy.2, io_getevents.2, io_setup.2, io_submit.2, ioctl_fat.2, ioctl_ficlonerange.2, ioctl_fideduperange.2, ioctl_tty.2, ioctl_userfaultfd.2, ioperm.2, iopl.2, ioprio_set.2, kcmp.2, kexec_load.2, keyctl.2, kill.2, link.2, listen.2, listxattr.2, llseek.2, lookup_dcookie.2, lseek.2, madvise.2, mbind.2, membarrier.2, memfd_create.2, migrate_pages.2, mincore.2, mkdir.2, mknod.2, mlock.2, mmap.2, mmap2.2, modify_ldt.2, move_pages.2, mprotect.2, mq_getsetattr.2, mremap.2, msgctl.2, msgget.2, msgop.2, msync.2, nanosleep.2, nfsservctl.2, nice.2, open_by_handle_at.2, outb.2, perf_event_open.2, perfmonctl.2, personality.2, pivot_root.2, pkey_alloc.2, poll.2, posix_fadvise.2, prctl.2, pread.2, process_vm_readv.2, ptrace.2, query_module.2, quotactl.2, read.2, readahead.2, readdir.2, readv.2, reboot.2, recv.2, recvmmsg.2, remap_file_pages.2, rename.2, request_key.2, restart_syscall.2, rt_sigqueueinfo.2, s390_pci_mmio_write.2, s390_runtime_instr.2, sched_get_priority_max.2, sched_rr_get_interval.2, sched_setaffinity.2, sched_setattr.2, sched_setparam.2, sched_setscheduler.2, sched_yield.2, seccomp.2, select.2, select_tut.2, semctl.2, semget.2, semop.2, send.2, sendfile.2, sendmmsg.2, set_mempolicy.2, set_thread_area.2, set_tid_address.2, seteuid.2, setfsgid.2, setfsuid.2, setgid.2, setns.2, setpgid.2, setresuid.2, setreuid.2, setsid.2, setuid.2, sgetmask.2, shmctl.2, shmget.2, shmop.2, sigaction.2, sigaltstack.2, sigpending.2, sigprocmask.2, sigreturn.2, sigsuspend.2, sigwaitinfo.2, socket.2, socketcall.2, socketpair.2, splice.2, spu_create.2, spu_run.2, stat.2, statfs.2, statx.2, subpage_prot.2, swapon.2, symlink.2, sync.2, sync_file_range.2, syscalls.2, sysctl.2, sysinfo.2, syslog.2, tee.2, time.2, timer_create.2, timer_getoverrun.2, timer_settime.2, timerfd_create.2, times.2, tkill.2, truncate.2, umask.2, umount.2, unimplemented.2, unlink.2, unshare.2, uselib.2, userfaultfd.2, utime.2, utimensat.2, vfork.2, vmsplice.2, wait.2, wait4.2, write.2: Formatting fix: replace blank lines with .PP/.IP
Blank lines shouldn't generally appear in *roff source (other
than in code examples), since they create large vertical
spaces between text blocks.
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2017-08-16 07:30:51 +00:00
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.PP
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2015-12-13 13:17:43 +00:00
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Use of memory barriers needs to be done taking into account that a
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memory barrier always needs to be either matched with its memory barrier
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2015-12-15 14:53:49 +00:00
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counterparts, or that the architecture's memory model doesn't require the
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2015-12-13 13:17:43 +00:00
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matching barriers.
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_syscall.2, bpf.2, cacheflush.2, capget.2, chdir.2, chmod.2, chroot.2, clock_getres.2, clock_nanosleep.2, clone.2, close.2, connect.2, copy_file_range.2, create_module.2, delete_module.2, dup.2, epoll_create.2, epoll_ctl.2, epoll_wait.2, eventfd.2, execve.2, execveat.2, fallocate.2, flock.2, fork.2, fsync.2, futex.2, futimesat.2, get_kernel_syms.2, get_mempolicy.2, get_robust_list.2, getcpu.2, getdents.2, getdomainname.2, getgid.2, getgroups.2, gethostname.2, getitimer.2, getpagesize.2, getpeername.2, getpriority.2, getrandom.2, getresuid.2, getrlimit.2, getrusage.2, getsid.2, getsockname.2, getsockopt.2, gettid.2, gettimeofday.2, getuid.2, getunwind.2, init_module.2, inotify_add_watch.2, inotify_init.2, inotify_rm_watch.2, intro.2, io_cancel.2, io_destroy.2, io_getevents.2, io_setup.2, io_submit.2, ioctl_fat.2, ioctl_ficlonerange.2, ioctl_fideduperange.2, ioctl_tty.2, ioctl_userfaultfd.2, ioperm.2, iopl.2, ioprio_set.2, kcmp.2, kexec_load.2, keyctl.2, kill.2, link.2, listen.2, listxattr.2, llseek.2, lookup_dcookie.2, lseek.2, madvise.2, mbind.2, membarrier.2, memfd_create.2, migrate_pages.2, mincore.2, mkdir.2, mknod.2, mlock.2, mmap.2, mmap2.2, modify_ldt.2, move_pages.2, mprotect.2, mq_getsetattr.2, mremap.2, msgctl.2, msgget.2, msgop.2, msync.2, nanosleep.2, nfsservctl.2, nice.2, open_by_handle_at.2, outb.2, perf_event_open.2, perfmonctl.2, personality.2, pivot_root.2, pkey_alloc.2, poll.2, posix_fadvise.2, prctl.2, pread.2, process_vm_readv.2, ptrace.2, query_module.2, quotactl.2, read.2, readahead.2, readdir.2, readv.2, reboot.2, recv.2, recvmmsg.2, remap_file_pages.2, rename.2, request_key.2, restart_syscall.2, rt_sigqueueinfo.2, s390_pci_mmio_write.2, s390_runtime_instr.2, sched_get_priority_max.2, sched_rr_get_interval.2, sched_setaffinity.2, sched_setattr.2, sched_setparam.2, sched_setscheduler.2, sched_yield.2, seccomp.2, select.2, select_tut.2, semctl.2, semget.2, semop.2, send.2, sendfile.2, sendmmsg.2, set_mempolicy.2, set_thread_area.2, set_tid_address.2, seteuid.2, setfsgid.2, setfsuid.2, setgid.2, setns.2, setpgid.2, setresuid.2, setreuid.2, setsid.2, setuid.2, sgetmask.2, shmctl.2, shmget.2, shmop.2, sigaction.2, sigaltstack.2, sigpending.2, sigprocmask.2, sigreturn.2, sigsuspend.2, sigwaitinfo.2, socket.2, socketcall.2, socketpair.2, splice.2, spu_create.2, spu_run.2, stat.2, statfs.2, statx.2, subpage_prot.2, swapon.2, symlink.2, sync.2, sync_file_range.2, syscalls.2, sysctl.2, sysinfo.2, syslog.2, tee.2, time.2, timer_create.2, timer_getoverrun.2, timer_settime.2, timerfd_create.2, times.2, tkill.2, truncate.2, umask.2, umount.2, unimplemented.2, unlink.2, unshare.2, uselib.2, userfaultfd.2, utime.2, utimensat.2, vfork.2, vmsplice.2, wait.2, wait4.2, write.2: Formatting fix: replace blank lines with .PP/.IP
Blank lines shouldn't generally appear in *roff source (other
than in code examples), since they create large vertical
spaces between text blocks.
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2017-08-16 07:30:51 +00:00
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.PP
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2015-12-13 13:17:43 +00:00
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There are cases where one side of the matching barriers (which we will
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refer to as "fast side") is executed much more often than the other
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2015-12-15 14:53:49 +00:00
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(which we will refer to as "slow side").
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This is a prime target for the use of
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.BR membarrier ().
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The key idea is to replace, for these matching
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barriers, the fast-side memory barriers by simple compiler barriers,
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for example:
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_syscall.2, bpf.2, cacheflush.2, capget.2, chdir.2, chmod.2, chroot.2, clock_getres.2, clock_nanosleep.2, clone.2, close.2, connect.2, copy_file_range.2, create_module.2, delete_module.2, dup.2, epoll_create.2, epoll_ctl.2, epoll_wait.2, eventfd.2, execve.2, execveat.2, fallocate.2, flock.2, fork.2, fsync.2, futex.2, futimesat.2, get_kernel_syms.2, get_mempolicy.2, get_robust_list.2, getcpu.2, getdents.2, getdomainname.2, getgid.2, getgroups.2, gethostname.2, getitimer.2, getpagesize.2, getpeername.2, getpriority.2, getrandom.2, getresuid.2, getrlimit.2, getrusage.2, getsid.2, getsockname.2, getsockopt.2, gettid.2, gettimeofday.2, getuid.2, getunwind.2, init_module.2, inotify_add_watch.2, inotify_init.2, inotify_rm_watch.2, intro.2, io_cancel.2, io_destroy.2, io_getevents.2, io_setup.2, io_submit.2, ioctl_fat.2, ioctl_ficlonerange.2, ioctl_fideduperange.2, ioctl_tty.2, ioctl_userfaultfd.2, ioperm.2, iopl.2, ioprio_set.2, kcmp.2, kexec_load.2, keyctl.2, kill.2, link.2, listen.2, listxattr.2, llseek.2, lookup_dcookie.2, lseek.2, madvise.2, mbind.2, membarrier.2, memfd_create.2, migrate_pages.2, mincore.2, mkdir.2, mknod.2, mlock.2, mmap.2, mmap2.2, modify_ldt.2, move_pages.2, mprotect.2, mq_getsetattr.2, mremap.2, msgctl.2, msgget.2, msgop.2, msync.2, nanosleep.2, nfsservctl.2, nice.2, open_by_handle_at.2, outb.2, perf_event_open.2, perfmonctl.2, personality.2, pivot_root.2, pkey_alloc.2, poll.2, posix_fadvise.2, prctl.2, pread.2, process_vm_readv.2, ptrace.2, query_module.2, quotactl.2, read.2, readahead.2, readdir.2, readv.2, reboot.2, recv.2, recvmmsg.2, remap_file_pages.2, rename.2, request_key.2, restart_syscall.2, rt_sigqueueinfo.2, s390_pci_mmio_write.2, s390_runtime_instr.2, sched_get_priority_max.2, sched_rr_get_interval.2, sched_setaffinity.2, sched_setattr.2, sched_setparam.2, sched_setscheduler.2, sched_yield.2, seccomp.2, select.2, select_tut.2, semctl.2, semget.2, semop.2, send.2, sendfile.2, sendmmsg.2, set_mempolicy.2, set_thread_area.2, set_tid_address.2, seteuid.2, setfsgid.2, setfsuid.2, setgid.2, setns.2, setpgid.2, setresuid.2, setreuid.2, setsid.2, setuid.2, sgetmask.2, shmctl.2, shmget.2, shmop.2, sigaction.2, sigaltstack.2, sigpending.2, sigprocmask.2, sigreturn.2, sigsuspend.2, sigwaitinfo.2, socket.2, socketcall.2, socketpair.2, splice.2, spu_create.2, spu_run.2, stat.2, statfs.2, statx.2, subpage_prot.2, swapon.2, symlink.2, sync.2, sync_file_range.2, syscalls.2, sysctl.2, sysinfo.2, syslog.2, tee.2, time.2, timer_create.2, timer_getoverrun.2, timer_settime.2, timerfd_create.2, times.2, tkill.2, truncate.2, umask.2, umount.2, unimplemented.2, unlink.2, unshare.2, uselib.2, userfaultfd.2, utime.2, utimensat.2, vfork.2, vmsplice.2, wait.2, wait4.2, write.2: Formatting fix: replace blank lines with .PP/.IP
Blank lines shouldn't generally appear in *roff source (other
than in code examples), since they create large vertical
spaces between text blocks.
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2017-08-16 07:30:51 +00:00
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.PP
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2015-12-15 14:53:49 +00:00
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asm volatile ("" : : : "memory")
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_syscall.2, bpf.2, cacheflush.2, capget.2, chdir.2, chmod.2, chroot.2, clock_getres.2, clock_nanosleep.2, clone.2, close.2, connect.2, copy_file_range.2, create_module.2, delete_module.2, dup.2, epoll_create.2, epoll_ctl.2, epoll_wait.2, eventfd.2, execve.2, execveat.2, fallocate.2, flock.2, fork.2, fsync.2, futex.2, futimesat.2, get_kernel_syms.2, get_mempolicy.2, get_robust_list.2, getcpu.2, getdents.2, getdomainname.2, getgid.2, getgroups.2, gethostname.2, getitimer.2, getpagesize.2, getpeername.2, getpriority.2, getrandom.2, getresuid.2, getrlimit.2, getrusage.2, getsid.2, getsockname.2, getsockopt.2, gettid.2, gettimeofday.2, getuid.2, getunwind.2, init_module.2, inotify_add_watch.2, inotify_init.2, inotify_rm_watch.2, intro.2, io_cancel.2, io_destroy.2, io_getevents.2, io_setup.2, io_submit.2, ioctl_fat.2, ioctl_ficlonerange.2, ioctl_fideduperange.2, ioctl_tty.2, ioctl_userfaultfd.2, ioperm.2, iopl.2, ioprio_set.2, kcmp.2, kexec_load.2, keyctl.2, kill.2, link.2, listen.2, listxattr.2, llseek.2, lookup_dcookie.2, lseek.2, madvise.2, mbind.2, membarrier.2, memfd_create.2, migrate_pages.2, mincore.2, mkdir.2, mknod.2, mlock.2, mmap.2, mmap2.2, modify_ldt.2, move_pages.2, mprotect.2, mq_getsetattr.2, mremap.2, msgctl.2, msgget.2, msgop.2, msync.2, nanosleep.2, nfsservctl.2, nice.2, open_by_handle_at.2, outb.2, perf_event_open.2, perfmonctl.2, personality.2, pivot_root.2, pkey_alloc.2, poll.2, posix_fadvise.2, prctl.2, pread.2, process_vm_readv.2, ptrace.2, query_module.2, quotactl.2, read.2, readahead.2, readdir.2, readv.2, reboot.2, recv.2, recvmmsg.2, remap_file_pages.2, rename.2, request_key.2, restart_syscall.2, rt_sigqueueinfo.2, s390_pci_mmio_write.2, s390_runtime_instr.2, sched_get_priority_max.2, sched_rr_get_interval.2, sched_setaffinity.2, sched_setattr.2, sched_setparam.2, sched_setscheduler.2, sched_yield.2, seccomp.2, select.2, select_tut.2, semctl.2, semget.2, semop.2, send.2, sendfile.2, sendmmsg.2, set_mempolicy.2, set_thread_area.2, set_tid_address.2, seteuid.2, setfsgid.2, setfsuid.2, setgid.2, setns.2, setpgid.2, setresuid.2, setreuid.2, setsid.2, setuid.2, sgetmask.2, shmctl.2, shmget.2, shmop.2, sigaction.2, sigaltstack.2, sigpending.2, sigprocmask.2, sigreturn.2, sigsuspend.2, sigwaitinfo.2, socket.2, socketcall.2, socketpair.2, splice.2, spu_create.2, spu_run.2, stat.2, statfs.2, statx.2, subpage_prot.2, swapon.2, symlink.2, sync.2, sync_file_range.2, syscalls.2, sysctl.2, sysinfo.2, syslog.2, tee.2, time.2, timer_create.2, timer_getoverrun.2, timer_settime.2, timerfd_create.2, times.2, tkill.2, truncate.2, umask.2, umount.2, unimplemented.2, unlink.2, unshare.2, uselib.2, userfaultfd.2, utime.2, utimensat.2, vfork.2, vmsplice.2, wait.2, wait4.2, write.2: Formatting fix: replace blank lines with .PP/.IP
Blank lines shouldn't generally appear in *roff source (other
than in code examples), since they create large vertical
spaces between text blocks.
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2017-08-16 07:30:51 +00:00
|
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.PP
|
2015-12-15 14:53:49 +00:00
|
|
|
and replace the slow-side memory barriers by calls to
|
|
|
|
.BR membarrier ().
|
_syscall.2, bpf.2, cacheflush.2, capget.2, chdir.2, chmod.2, chroot.2, clock_getres.2, clock_nanosleep.2, clone.2, close.2, connect.2, copy_file_range.2, create_module.2, delete_module.2, dup.2, epoll_create.2, epoll_ctl.2, epoll_wait.2, eventfd.2, execve.2, execveat.2, fallocate.2, flock.2, fork.2, fsync.2, futex.2, futimesat.2, get_kernel_syms.2, get_mempolicy.2, get_robust_list.2, getcpu.2, getdents.2, getdomainname.2, getgid.2, getgroups.2, gethostname.2, getitimer.2, getpagesize.2, getpeername.2, getpriority.2, getrandom.2, getresuid.2, getrlimit.2, getrusage.2, getsid.2, getsockname.2, getsockopt.2, gettid.2, gettimeofday.2, getuid.2, getunwind.2, init_module.2, inotify_add_watch.2, inotify_init.2, inotify_rm_watch.2, intro.2, io_cancel.2, io_destroy.2, io_getevents.2, io_setup.2, io_submit.2, ioctl_fat.2, ioctl_ficlonerange.2, ioctl_fideduperange.2, ioctl_tty.2, ioctl_userfaultfd.2, ioperm.2, iopl.2, ioprio_set.2, kcmp.2, kexec_load.2, keyctl.2, kill.2, link.2, listen.2, listxattr.2, llseek.2, lookup_dcookie.2, lseek.2, madvise.2, mbind.2, membarrier.2, memfd_create.2, migrate_pages.2, mincore.2, mkdir.2, mknod.2, mlock.2, mmap.2, mmap2.2, modify_ldt.2, move_pages.2, mprotect.2, mq_getsetattr.2, mremap.2, msgctl.2, msgget.2, msgop.2, msync.2, nanosleep.2, nfsservctl.2, nice.2, open_by_handle_at.2, outb.2, perf_event_open.2, perfmonctl.2, personality.2, pivot_root.2, pkey_alloc.2, poll.2, posix_fadvise.2, prctl.2, pread.2, process_vm_readv.2, ptrace.2, query_module.2, quotactl.2, read.2, readahead.2, readdir.2, readv.2, reboot.2, recv.2, recvmmsg.2, remap_file_pages.2, rename.2, request_key.2, restart_syscall.2, rt_sigqueueinfo.2, s390_pci_mmio_write.2, s390_runtime_instr.2, sched_get_priority_max.2, sched_rr_get_interval.2, sched_setaffinity.2, sched_setattr.2, sched_setparam.2, sched_setscheduler.2, sched_yield.2, seccomp.2, select.2, select_tut.2, semctl.2, semget.2, semop.2, send.2, sendfile.2, sendmmsg.2, set_mempolicy.2, set_thread_area.2, set_tid_address.2, seteuid.2, setfsgid.2, setfsuid.2, setgid.2, setns.2, setpgid.2, setresuid.2, setreuid.2, setsid.2, setuid.2, sgetmask.2, shmctl.2, shmget.2, shmop.2, sigaction.2, sigaltstack.2, sigpending.2, sigprocmask.2, sigreturn.2, sigsuspend.2, sigwaitinfo.2, socket.2, socketcall.2, socketpair.2, splice.2, spu_create.2, spu_run.2, stat.2, statfs.2, statx.2, subpage_prot.2, swapon.2, symlink.2, sync.2, sync_file_range.2, syscalls.2, sysctl.2, sysinfo.2, syslog.2, tee.2, time.2, timer_create.2, timer_getoverrun.2, timer_settime.2, timerfd_create.2, times.2, tkill.2, truncate.2, umask.2, umount.2, unimplemented.2, unlink.2, unshare.2, uselib.2, userfaultfd.2, utime.2, utimensat.2, vfork.2, vmsplice.2, wait.2, wait4.2, write.2: Formatting fix: replace blank lines with .PP/.IP
Blank lines shouldn't generally appear in *roff source (other
than in code examples), since they create large vertical
spaces between text blocks.
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2017-08-16 07:30:51 +00:00
|
|
|
.PP
|
2015-12-13 13:17:43 +00:00
|
|
|
This will add overhead to the slow side, and remove overhead from the
|
|
|
|
fast side, thus resulting in an overall performance increase as long as
|
2015-12-15 14:53:49 +00:00
|
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|
the slow side is infrequent enough that the overhead of the
|
|
|
|
.BR membarrier ()
|
|
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|
calls does not outweigh the performance gain on the fast side.
|
_syscall.2, bpf.2, cacheflush.2, capget.2, chdir.2, chmod.2, chroot.2, clock_getres.2, clock_nanosleep.2, clone.2, close.2, connect.2, copy_file_range.2, create_module.2, delete_module.2, dup.2, epoll_create.2, epoll_ctl.2, epoll_wait.2, eventfd.2, execve.2, execveat.2, fallocate.2, flock.2, fork.2, fsync.2, futex.2, futimesat.2, get_kernel_syms.2, get_mempolicy.2, get_robust_list.2, getcpu.2, getdents.2, getdomainname.2, getgid.2, getgroups.2, gethostname.2, getitimer.2, getpagesize.2, getpeername.2, getpriority.2, getrandom.2, getresuid.2, getrlimit.2, getrusage.2, getsid.2, getsockname.2, getsockopt.2, gettid.2, gettimeofday.2, getuid.2, getunwind.2, init_module.2, inotify_add_watch.2, inotify_init.2, inotify_rm_watch.2, intro.2, io_cancel.2, io_destroy.2, io_getevents.2, io_setup.2, io_submit.2, ioctl_fat.2, ioctl_ficlonerange.2, ioctl_fideduperange.2, ioctl_tty.2, ioctl_userfaultfd.2, ioperm.2, iopl.2, ioprio_set.2, kcmp.2, kexec_load.2, keyctl.2, kill.2, link.2, listen.2, listxattr.2, llseek.2, lookup_dcookie.2, lseek.2, madvise.2, mbind.2, membarrier.2, memfd_create.2, migrate_pages.2, mincore.2, mkdir.2, mknod.2, mlock.2, mmap.2, mmap2.2, modify_ldt.2, move_pages.2, mprotect.2, mq_getsetattr.2, mremap.2, msgctl.2, msgget.2, msgop.2, msync.2, nanosleep.2, nfsservctl.2, nice.2, open_by_handle_at.2, outb.2, perf_event_open.2, perfmonctl.2, personality.2, pivot_root.2, pkey_alloc.2, poll.2, posix_fadvise.2, prctl.2, pread.2, process_vm_readv.2, ptrace.2, query_module.2, quotactl.2, read.2, readahead.2, readdir.2, readv.2, reboot.2, recv.2, recvmmsg.2, remap_file_pages.2, rename.2, request_key.2, restart_syscall.2, rt_sigqueueinfo.2, s390_pci_mmio_write.2, s390_runtime_instr.2, sched_get_priority_max.2, sched_rr_get_interval.2, sched_setaffinity.2, sched_setattr.2, sched_setparam.2, sched_setscheduler.2, sched_yield.2, seccomp.2, select.2, select_tut.2, semctl.2, semget.2, semop.2, send.2, sendfile.2, sendmmsg.2, set_mempolicy.2, set_thread_area.2, set_tid_address.2, seteuid.2, setfsgid.2, setfsuid.2, setgid.2, setns.2, setpgid.2, setresuid.2, setreuid.2, setsid.2, setuid.2, sgetmask.2, shmctl.2, shmget.2, shmop.2, sigaction.2, sigaltstack.2, sigpending.2, sigprocmask.2, sigreturn.2, sigsuspend.2, sigwaitinfo.2, socket.2, socketcall.2, socketpair.2, splice.2, spu_create.2, spu_run.2, stat.2, statfs.2, statx.2, subpage_prot.2, swapon.2, symlink.2, sync.2, sync_file_range.2, syscalls.2, sysctl.2, sysinfo.2, syslog.2, tee.2, time.2, timer_create.2, timer_getoverrun.2, timer_settime.2, timerfd_create.2, times.2, tkill.2, truncate.2, umask.2, umount.2, unimplemented.2, unlink.2, unshare.2, uselib.2, userfaultfd.2, utime.2, utimensat.2, vfork.2, vmsplice.2, wait.2, wait4.2, write.2: Formatting fix: replace blank lines with .PP/.IP
Blank lines shouldn't generally appear in *roff source (other
than in code examples), since they create large vertical
spaces between text blocks.
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2017-08-16 07:30:51 +00:00
|
|
|
.PP
|
2015-12-13 13:17:43 +00:00
|
|
|
The
|
|
|
|
.I cmd
|
|
|
|
argument is one of the following:
|
|
|
|
.TP
|
|
|
|
.B MEMBARRIER_CMD_QUERY
|
2015-12-15 14:53:49 +00:00
|
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|
Query the set of supported commands.
|
|
|
|
The return value of the call is a bit mask of supported
|
2015-12-13 13:17:43 +00:00
|
|
|
commands.
|
2015-12-15 15:23:11 +00:00
|
|
|
.BR MEMBARRIER_CMD_QUERY ,
|
|
|
|
which has the value 0,
|
|
|
|
is not itself included in this bit mask.
|
|
|
|
This command is always supported (on kernels where
|
|
|
|
.BR membarrier ()
|
|
|
|
is provided).
|
2015-12-13 13:17:43 +00:00
|
|
|
.TP
|
|
|
|
.B MEMBARRIER_CMD_SHARED
|
|
|
|
Ensure that all threads from all processes on the system pass through a
|
|
|
|
state where all memory accesses to user-space addresses match program
|
2015-12-15 14:53:49 +00:00
|
|
|
order between entry to and return from the
|
|
|
|
.BR membarrier ()
|
|
|
|
system call.
|
|
|
|
All threads on the system are targeted by this command.
|
2015-12-13 13:17:43 +00:00
|
|
|
.PP
|
|
|
|
The
|
|
|
|
.I flags
|
2015-12-15 14:53:49 +00:00
|
|
|
argument is currently unused and must be specified as 0.
|
2015-12-13 13:17:43 +00:00
|
|
|
.PP
|
|
|
|
All memory accesses performed in program order from each targeted thread
|
2015-12-15 14:53:49 +00:00
|
|
|
are guaranteed to be ordered with respect to
|
|
|
|
.BR membarrier ().
|
_syscall.2, bpf.2, cacheflush.2, capget.2, chdir.2, chmod.2, chroot.2, clock_getres.2, clock_nanosleep.2, clone.2, close.2, connect.2, copy_file_range.2, create_module.2, delete_module.2, dup.2, epoll_create.2, epoll_ctl.2, epoll_wait.2, eventfd.2, execve.2, execveat.2, fallocate.2, flock.2, fork.2, fsync.2, futex.2, futimesat.2, get_kernel_syms.2, get_mempolicy.2, get_robust_list.2, getcpu.2, getdents.2, getdomainname.2, getgid.2, getgroups.2, gethostname.2, getitimer.2, getpagesize.2, getpeername.2, getpriority.2, getrandom.2, getresuid.2, getrlimit.2, getrusage.2, getsid.2, getsockname.2, getsockopt.2, gettid.2, gettimeofday.2, getuid.2, getunwind.2, init_module.2, inotify_add_watch.2, inotify_init.2, inotify_rm_watch.2, intro.2, io_cancel.2, io_destroy.2, io_getevents.2, io_setup.2, io_submit.2, ioctl_fat.2, ioctl_ficlonerange.2, ioctl_fideduperange.2, ioctl_tty.2, ioctl_userfaultfd.2, ioperm.2, iopl.2, ioprio_set.2, kcmp.2, kexec_load.2, keyctl.2, kill.2, link.2, listen.2, listxattr.2, llseek.2, lookup_dcookie.2, lseek.2, madvise.2, mbind.2, membarrier.2, memfd_create.2, migrate_pages.2, mincore.2, mkdir.2, mknod.2, mlock.2, mmap.2, mmap2.2, modify_ldt.2, move_pages.2, mprotect.2, mq_getsetattr.2, mremap.2, msgctl.2, msgget.2, msgop.2, msync.2, nanosleep.2, nfsservctl.2, nice.2, open_by_handle_at.2, outb.2, perf_event_open.2, perfmonctl.2, personality.2, pivot_root.2, pkey_alloc.2, poll.2, posix_fadvise.2, prctl.2, pread.2, process_vm_readv.2, ptrace.2, query_module.2, quotactl.2, read.2, readahead.2, readdir.2, readv.2, reboot.2, recv.2, recvmmsg.2, remap_file_pages.2, rename.2, request_key.2, restart_syscall.2, rt_sigqueueinfo.2, s390_pci_mmio_write.2, s390_runtime_instr.2, sched_get_priority_max.2, sched_rr_get_interval.2, sched_setaffinity.2, sched_setattr.2, sched_setparam.2, sched_setscheduler.2, sched_yield.2, seccomp.2, select.2, select_tut.2, semctl.2, semget.2, semop.2, send.2, sendfile.2, sendmmsg.2, set_mempolicy.2, set_thread_area.2, set_tid_address.2, seteuid.2, setfsgid.2, setfsuid.2, setgid.2, setns.2, setpgid.2, setresuid.2, setreuid.2, setsid.2, setuid.2, sgetmask.2, shmctl.2, shmget.2, shmop.2, sigaction.2, sigaltstack.2, sigpending.2, sigprocmask.2, sigreturn.2, sigsuspend.2, sigwaitinfo.2, socket.2, socketcall.2, socketpair.2, splice.2, spu_create.2, spu_run.2, stat.2, statfs.2, statx.2, subpage_prot.2, swapon.2, symlink.2, sync.2, sync_file_range.2, syscalls.2, sysctl.2, sysinfo.2, syslog.2, tee.2, time.2, timer_create.2, timer_getoverrun.2, timer_settime.2, timerfd_create.2, times.2, tkill.2, truncate.2, umask.2, umount.2, unimplemented.2, unlink.2, unshare.2, uselib.2, userfaultfd.2, utime.2, utimensat.2, vfork.2, vmsplice.2, wait.2, wait4.2, write.2: Formatting fix: replace blank lines with .PP/.IP
Blank lines shouldn't generally appear in *roff source (other
than in code examples), since they create large vertical
spaces between text blocks.
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2017-08-16 07:30:51 +00:00
|
|
|
.PP
|
2015-12-15 14:53:49 +00:00
|
|
|
If we use the semantic
|
|
|
|
.I barrier()
|
|
|
|
to represent a compiler barrier forcing memory
|
2015-12-13 13:17:43 +00:00
|
|
|
accesses to be performed in program order across the barrier, and
|
2015-12-15 14:53:49 +00:00
|
|
|
.I smp_mb()
|
|
|
|
to represent explicit memory barriers forcing full memory
|
2015-12-13 13:17:43 +00:00
|
|
|
ordering across the barrier, we have the following ordering table for
|
2015-12-15 14:53:49 +00:00
|
|
|
each pairing of
|
|
|
|
.IR barrier() ,
|
|
|
|
.BR membarrier ()
|
|
|
|
and
|
|
|
|
.IR smp_mb() .
|
2015-12-13 13:17:43 +00:00
|
|
|
The pair ordering is detailed as (O: ordered, X: not ordered):
|
_syscall.2, bpf.2, cacheflush.2, capget.2, chdir.2, chmod.2, chroot.2, clock_getres.2, clock_nanosleep.2, clone.2, close.2, connect.2, copy_file_range.2, create_module.2, delete_module.2, dup.2, epoll_create.2, epoll_ctl.2, epoll_wait.2, eventfd.2, execve.2, execveat.2, fallocate.2, flock.2, fork.2, fsync.2, futex.2, futimesat.2, get_kernel_syms.2, get_mempolicy.2, get_robust_list.2, getcpu.2, getdents.2, getdomainname.2, getgid.2, getgroups.2, gethostname.2, getitimer.2, getpagesize.2, getpeername.2, getpriority.2, getrandom.2, getresuid.2, getrlimit.2, getrusage.2, getsid.2, getsockname.2, getsockopt.2, gettid.2, gettimeofday.2, getuid.2, getunwind.2, init_module.2, inotify_add_watch.2, inotify_init.2, inotify_rm_watch.2, intro.2, io_cancel.2, io_destroy.2, io_getevents.2, io_setup.2, io_submit.2, ioctl_fat.2, ioctl_ficlonerange.2, ioctl_fideduperange.2, ioctl_tty.2, ioctl_userfaultfd.2, ioperm.2, iopl.2, ioprio_set.2, kcmp.2, kexec_load.2, keyctl.2, kill.2, link.2, listen.2, listxattr.2, llseek.2, lookup_dcookie.2, lseek.2, madvise.2, mbind.2, membarrier.2, memfd_create.2, migrate_pages.2, mincore.2, mkdir.2, mknod.2, mlock.2, mmap.2, mmap2.2, modify_ldt.2, move_pages.2, mprotect.2, mq_getsetattr.2, mremap.2, msgctl.2, msgget.2, msgop.2, msync.2, nanosleep.2, nfsservctl.2, nice.2, open_by_handle_at.2, outb.2, perf_event_open.2, perfmonctl.2, personality.2, pivot_root.2, pkey_alloc.2, poll.2, posix_fadvise.2, prctl.2, pread.2, process_vm_readv.2, ptrace.2, query_module.2, quotactl.2, read.2, readahead.2, readdir.2, readv.2, reboot.2, recv.2, recvmmsg.2, remap_file_pages.2, rename.2, request_key.2, restart_syscall.2, rt_sigqueueinfo.2, s390_pci_mmio_write.2, s390_runtime_instr.2, sched_get_priority_max.2, sched_rr_get_interval.2, sched_setaffinity.2, sched_setattr.2, sched_setparam.2, sched_setscheduler.2, sched_yield.2, seccomp.2, select.2, select_tut.2, semctl.2, semget.2, semop.2, send.2, sendfile.2, sendmmsg.2, set_mempolicy.2, set_thread_area.2, set_tid_address.2, seteuid.2, setfsgid.2, setfsuid.2, setgid.2, setns.2, setpgid.2, setresuid.2, setreuid.2, setsid.2, setuid.2, sgetmask.2, shmctl.2, shmget.2, shmop.2, sigaction.2, sigaltstack.2, sigpending.2, sigprocmask.2, sigreturn.2, sigsuspend.2, sigwaitinfo.2, socket.2, socketcall.2, socketpair.2, splice.2, spu_create.2, spu_run.2, stat.2, statfs.2, statx.2, subpage_prot.2, swapon.2, symlink.2, sync.2, sync_file_range.2, syscalls.2, sysctl.2, sysinfo.2, syslog.2, tee.2, time.2, timer_create.2, timer_getoverrun.2, timer_settime.2, timerfd_create.2, times.2, tkill.2, truncate.2, umask.2, umount.2, unimplemented.2, unlink.2, unshare.2, uselib.2, userfaultfd.2, utime.2, utimensat.2, vfork.2, vmsplice.2, wait.2, wait4.2, write.2: Formatting fix: replace blank lines with .PP/.IP
Blank lines shouldn't generally appear in *roff source (other
than in code examples), since they create large vertical
spaces between text blocks.
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2017-08-16 07:30:51 +00:00
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.PP
|
2015-12-15 14:53:49 +00:00
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barrier() smp_mb() membarrier()
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barrier() X X O
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smp_mb() X O O
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2015-12-15 18:54:10 +00:00
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membarrier() O O O
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2015-12-13 13:17:43 +00:00
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.SH RETURN VALUE
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2015-12-15 15:11:06 +00:00
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On success, the
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.B MEMBARRIER_CMD_QUERY
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operation returns a bit mask of supported commands and the
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.B MEMBARRIER_CMD_SHARED
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operation returns zero.
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2015-12-15 14:53:49 +00:00
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On error, \-1 is returned,
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2015-12-13 13:17:43 +00:00
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and
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.I errno
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is set appropriately.
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_syscall.2, bpf.2, cacheflush.2, capget.2, chdir.2, chmod.2, chroot.2, clock_getres.2, clock_nanosleep.2, clone.2, close.2, connect.2, copy_file_range.2, create_module.2, delete_module.2, dup.2, epoll_create.2, epoll_ctl.2, epoll_wait.2, eventfd.2, execve.2, execveat.2, fallocate.2, flock.2, fork.2, fsync.2, futex.2, futimesat.2, get_kernel_syms.2, get_mempolicy.2, get_robust_list.2, getcpu.2, getdents.2, getdomainname.2, getgid.2, getgroups.2, gethostname.2, getitimer.2, getpagesize.2, getpeername.2, getpriority.2, getrandom.2, getresuid.2, getrlimit.2, getrusage.2, getsid.2, getsockname.2, getsockopt.2, gettid.2, gettimeofday.2, getuid.2, getunwind.2, init_module.2, inotify_add_watch.2, inotify_init.2, inotify_rm_watch.2, intro.2, io_cancel.2, io_destroy.2, io_getevents.2, io_setup.2, io_submit.2, ioctl_fat.2, ioctl_ficlonerange.2, ioctl_fideduperange.2, ioctl_tty.2, ioctl_userfaultfd.2, ioperm.2, iopl.2, ioprio_set.2, kcmp.2, kexec_load.2, keyctl.2, kill.2, link.2, listen.2, listxattr.2, llseek.2, lookup_dcookie.2, lseek.2, madvise.2, mbind.2, membarrier.2, memfd_create.2, migrate_pages.2, mincore.2, mkdir.2, mknod.2, mlock.2, mmap.2, mmap2.2, modify_ldt.2, move_pages.2, mprotect.2, mq_getsetattr.2, mremap.2, msgctl.2, msgget.2, msgop.2, msync.2, nanosleep.2, nfsservctl.2, nice.2, open_by_handle_at.2, outb.2, perf_event_open.2, perfmonctl.2, personality.2, pivot_root.2, pkey_alloc.2, poll.2, posix_fadvise.2, prctl.2, pread.2, process_vm_readv.2, ptrace.2, query_module.2, quotactl.2, read.2, readahead.2, readdir.2, readv.2, reboot.2, recv.2, recvmmsg.2, remap_file_pages.2, rename.2, request_key.2, restart_syscall.2, rt_sigqueueinfo.2, s390_pci_mmio_write.2, s390_runtime_instr.2, sched_get_priority_max.2, sched_rr_get_interval.2, sched_setaffinity.2, sched_setattr.2, sched_setparam.2, sched_setscheduler.2, sched_yield.2, seccomp.2, select.2, select_tut.2, semctl.2, semget.2, semop.2, send.2, sendfile.2, sendmmsg.2, set_mempolicy.2, set_thread_area.2, set_tid_address.2, seteuid.2, setfsgid.2, setfsuid.2, setgid.2, setns.2, setpgid.2, setresuid.2, setreuid.2, setsid.2, setuid.2, sgetmask.2, shmctl.2, shmget.2, shmop.2, sigaction.2, sigaltstack.2, sigpending.2, sigprocmask.2, sigreturn.2, sigsuspend.2, sigwaitinfo.2, socket.2, socketcall.2, socketpair.2, splice.2, spu_create.2, spu_run.2, stat.2, statfs.2, statx.2, subpage_prot.2, swapon.2, symlink.2, sync.2, sync_file_range.2, syscalls.2, sysctl.2, sysinfo.2, syslog.2, tee.2, time.2, timer_create.2, timer_getoverrun.2, timer_settime.2, timerfd_create.2, times.2, tkill.2, truncate.2, umask.2, umount.2, unimplemented.2, unlink.2, unshare.2, uselib.2, userfaultfd.2, utime.2, utimensat.2, vfork.2, vmsplice.2, wait.2, wait4.2, write.2: Formatting fix: replace blank lines with .PP/.IP
Blank lines shouldn't generally appear in *roff source (other
than in code examples), since they create large vertical
spaces between text blocks.
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2017-08-16 07:30:51 +00:00
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.PP
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2015-12-15 15:15:39 +00:00
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For a given command, with
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.I flags
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set to 0, this system call is
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2015-12-15 14:53:49 +00:00
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guaranteed to always return the same value until reboot.
|
2015-12-15 15:15:39 +00:00
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Further calls with the same arguments will lead to the same result.
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Therefore, with
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.I flags
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set to 0, error handling is required only for the first call to
|
|
|
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.BR membarrier ().
|
2015-12-13 13:17:43 +00:00
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|
.SH ERRORS
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.TP
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.B EINVAL
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.I cmd
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is invalid or
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.I flags
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is non-zero.
|
2015-12-15 14:53:49 +00:00
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.TP
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.B ENOSYS
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The
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|
.BR membarrier ()
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|
system call is not implemented by this kernel.
|
2017-05-22 12:46:23 +00:00
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.TP
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.BR ENOSYS " (since Linux 4.11)"
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.\" 907565337ebf998a68cb5c5b2174ce5e5da065eb
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The
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.BR membarrier ()
|
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|
system call is disabled because the
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.I nohz_full
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CPU parameter has been set.
|
2015-12-13 13:17:43 +00:00
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.SH VERSIONS
|
2015-12-15 14:53:49 +00:00
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|
The
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|
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|
.BR membarrier ()
|
|
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|
system call was added in Linux 4.3.
|
membarrier.2, crypt.3, dladdr.3, duplocale.3, fmemopen.3, gethostbyname.3, mallopt.3, newlocale.3, resolver.3, sigsetops.3, strfmon.3, tzset.3, console_ioctl.4, lirc.4, loop.4, vcs.4, dir_colors.5, locale.5, proc.5, tzfile.5, attributes.7, bootparam.7, capabilities.7, feature_test_macros.7, icmp.7, man-pages.7, netlink.7, path_resolution.7, pipe.7, socket.7, unix.7, vdso.7: ffix
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2016-02-03 08:14:22 +00:00
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.\"
|
2015-12-13 13:17:43 +00:00
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|
.SH CONFORMING TO
|
|
|
|
.BR membarrier ()
|
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|
|
is Linux-specific.
|
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|
.SH NOTES
|
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|
A memory barrier instruction is part of the instruction set of
|
2015-12-15 14:53:49 +00:00
|
|
|
architectures with weakly-ordered memory models.
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It orders memory
|
2015-12-13 13:17:43 +00:00
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|
accesses prior to the barrier and after the barrier with respect to
|
2015-12-15 14:53:49 +00:00
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|
matching barriers on other cores.
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For instance, a load fence can order
|
2015-12-13 13:17:43 +00:00
|
|
|
loads prior to and following that fence with respect to stores ordered
|
|
|
|
by store fences.
|
_syscall.2, bpf.2, cacheflush.2, capget.2, chdir.2, chmod.2, chroot.2, clock_getres.2, clock_nanosleep.2, clone.2, close.2, connect.2, copy_file_range.2, create_module.2, delete_module.2, dup.2, epoll_create.2, epoll_ctl.2, epoll_wait.2, eventfd.2, execve.2, execveat.2, fallocate.2, flock.2, fork.2, fsync.2, futex.2, futimesat.2, get_kernel_syms.2, get_mempolicy.2, get_robust_list.2, getcpu.2, getdents.2, getdomainname.2, getgid.2, getgroups.2, gethostname.2, getitimer.2, getpagesize.2, getpeername.2, getpriority.2, getrandom.2, getresuid.2, getrlimit.2, getrusage.2, getsid.2, getsockname.2, getsockopt.2, gettid.2, gettimeofday.2, getuid.2, getunwind.2, init_module.2, inotify_add_watch.2, inotify_init.2, inotify_rm_watch.2, intro.2, io_cancel.2, io_destroy.2, io_getevents.2, io_setup.2, io_submit.2, ioctl_fat.2, ioctl_ficlonerange.2, ioctl_fideduperange.2, ioctl_tty.2, ioctl_userfaultfd.2, ioperm.2, iopl.2, ioprio_set.2, kcmp.2, kexec_load.2, keyctl.2, kill.2, link.2, listen.2, listxattr.2, llseek.2, lookup_dcookie.2, lseek.2, madvise.2, mbind.2, membarrier.2, memfd_create.2, migrate_pages.2, mincore.2, mkdir.2, mknod.2, mlock.2, mmap.2, mmap2.2, modify_ldt.2, move_pages.2, mprotect.2, mq_getsetattr.2, mremap.2, msgctl.2, msgget.2, msgop.2, msync.2, nanosleep.2, nfsservctl.2, nice.2, open_by_handle_at.2, outb.2, perf_event_open.2, perfmonctl.2, personality.2, pivot_root.2, pkey_alloc.2, poll.2, posix_fadvise.2, prctl.2, pread.2, process_vm_readv.2, ptrace.2, query_module.2, quotactl.2, read.2, readahead.2, readdir.2, readv.2, reboot.2, recv.2, recvmmsg.2, remap_file_pages.2, rename.2, request_key.2, restart_syscall.2, rt_sigqueueinfo.2, s390_pci_mmio_write.2, s390_runtime_instr.2, sched_get_priority_max.2, sched_rr_get_interval.2, sched_setaffinity.2, sched_setattr.2, sched_setparam.2, sched_setscheduler.2, sched_yield.2, seccomp.2, select.2, select_tut.2, semctl.2, semget.2, semop.2, send.2, sendfile.2, sendmmsg.2, set_mempolicy.2, set_thread_area.2, set_tid_address.2, seteuid.2, setfsgid.2, setfsuid.2, setgid.2, setns.2, setpgid.2, setresuid.2, setreuid.2, setsid.2, setuid.2, sgetmask.2, shmctl.2, shmget.2, shmop.2, sigaction.2, sigaltstack.2, sigpending.2, sigprocmask.2, sigreturn.2, sigsuspend.2, sigwaitinfo.2, socket.2, socketcall.2, socketpair.2, splice.2, spu_create.2, spu_run.2, stat.2, statfs.2, statx.2, subpage_prot.2, swapon.2, symlink.2, sync.2, sync_file_range.2, syscalls.2, sysctl.2, sysinfo.2, syslog.2, tee.2, time.2, timer_create.2, timer_getoverrun.2, timer_settime.2, timerfd_create.2, times.2, tkill.2, truncate.2, umask.2, umount.2, unimplemented.2, unlink.2, unshare.2, uselib.2, userfaultfd.2, utime.2, utimensat.2, vfork.2, vmsplice.2, wait.2, wait4.2, write.2: Formatting fix: replace blank lines with .PP/.IP
Blank lines shouldn't generally appear in *roff source (other
than in code examples), since they create large vertical
spaces between text blocks.
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2017-08-16 07:30:51 +00:00
|
|
|
.PP
|
2015-12-13 13:17:43 +00:00
|
|
|
Program order is the order in which instructions are ordered in the
|
|
|
|
program assembly code.
|
_syscall.2, bpf.2, cacheflush.2, capget.2, chdir.2, chmod.2, chroot.2, clock_getres.2, clock_nanosleep.2, clone.2, close.2, connect.2, copy_file_range.2, create_module.2, delete_module.2, dup.2, epoll_create.2, epoll_ctl.2, epoll_wait.2, eventfd.2, execve.2, execveat.2, fallocate.2, flock.2, fork.2, fsync.2, futex.2, futimesat.2, get_kernel_syms.2, get_mempolicy.2, get_robust_list.2, getcpu.2, getdents.2, getdomainname.2, getgid.2, getgroups.2, gethostname.2, getitimer.2, getpagesize.2, getpeername.2, getpriority.2, getrandom.2, getresuid.2, getrlimit.2, getrusage.2, getsid.2, getsockname.2, getsockopt.2, gettid.2, gettimeofday.2, getuid.2, getunwind.2, init_module.2, inotify_add_watch.2, inotify_init.2, inotify_rm_watch.2, intro.2, io_cancel.2, io_destroy.2, io_getevents.2, io_setup.2, io_submit.2, ioctl_fat.2, ioctl_ficlonerange.2, ioctl_fideduperange.2, ioctl_tty.2, ioctl_userfaultfd.2, ioperm.2, iopl.2, ioprio_set.2, kcmp.2, kexec_load.2, keyctl.2, kill.2, link.2, listen.2, listxattr.2, llseek.2, lookup_dcookie.2, lseek.2, madvise.2, mbind.2, membarrier.2, memfd_create.2, migrate_pages.2, mincore.2, mkdir.2, mknod.2, mlock.2, mmap.2, mmap2.2, modify_ldt.2, move_pages.2, mprotect.2, mq_getsetattr.2, mremap.2, msgctl.2, msgget.2, msgop.2, msync.2, nanosleep.2, nfsservctl.2, nice.2, open_by_handle_at.2, outb.2, perf_event_open.2, perfmonctl.2, personality.2, pivot_root.2, pkey_alloc.2, poll.2, posix_fadvise.2, prctl.2, pread.2, process_vm_readv.2, ptrace.2, query_module.2, quotactl.2, read.2, readahead.2, readdir.2, readv.2, reboot.2, recv.2, recvmmsg.2, remap_file_pages.2, rename.2, request_key.2, restart_syscall.2, rt_sigqueueinfo.2, s390_pci_mmio_write.2, s390_runtime_instr.2, sched_get_priority_max.2, sched_rr_get_interval.2, sched_setaffinity.2, sched_setattr.2, sched_setparam.2, sched_setscheduler.2, sched_yield.2, seccomp.2, select.2, select_tut.2, semctl.2, semget.2, semop.2, send.2, sendfile.2, sendmmsg.2, set_mempolicy.2, set_thread_area.2, set_tid_address.2, seteuid.2, setfsgid.2, setfsuid.2, setgid.2, setns.2, setpgid.2, setresuid.2, setreuid.2, setsid.2, setuid.2, sgetmask.2, shmctl.2, shmget.2, shmop.2, sigaction.2, sigaltstack.2, sigpending.2, sigprocmask.2, sigreturn.2, sigsuspend.2, sigwaitinfo.2, socket.2, socketcall.2, socketpair.2, splice.2, spu_create.2, spu_run.2, stat.2, statfs.2, statx.2, subpage_prot.2, swapon.2, symlink.2, sync.2, sync_file_range.2, syscalls.2, sysctl.2, sysinfo.2, syslog.2, tee.2, time.2, timer_create.2, timer_getoverrun.2, timer_settime.2, timerfd_create.2, times.2, tkill.2, truncate.2, umask.2, umount.2, unimplemented.2, unlink.2, unshare.2, uselib.2, userfaultfd.2, utime.2, utimensat.2, vfork.2, vmsplice.2, wait.2, wait4.2, write.2: Formatting fix: replace blank lines with .PP/.IP
Blank lines shouldn't generally appear in *roff source (other
than in code examples), since they create large vertical
spaces between text blocks.
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2017-08-16 07:30:51 +00:00
|
|
|
.PP
|
2015-12-15 14:53:49 +00:00
|
|
|
Examples where
|
|
|
|
.BR membarrier ()
|
|
|
|
can be useful include implementations
|
2015-12-18 19:41:00 +00:00
|
|
|
of Read-Copy-Update libraries and garbage collectors.
|
2015-12-13 13:17:43 +00:00
|
|
|
.SH EXAMPLE
|
|
|
|
Assuming a multithreaded application where "fast_path()" is executed
|
|
|
|
very frequently, and where "slow_path()" is executed infrequently, the
|
|
|
|
following code (x86) can be transformed using
|
2015-12-15 14:53:49 +00:00
|
|
|
.BR membarrier ():
|
_syscall.2, bpf.2, cacheflush.2, capget.2, chdir.2, chmod.2, chroot.2, clock_getres.2, clock_nanosleep.2, clone.2, close.2, connect.2, copy_file_range.2, create_module.2, delete_module.2, dup.2, epoll_create.2, epoll_ctl.2, epoll_wait.2, eventfd.2, execve.2, execveat.2, fallocate.2, flock.2, fork.2, fsync.2, futex.2, futimesat.2, get_kernel_syms.2, get_mempolicy.2, get_robust_list.2, getcpu.2, getdents.2, getdomainname.2, getgid.2, getgroups.2, gethostname.2, getitimer.2, getpagesize.2, getpeername.2, getpriority.2, getrandom.2, getresuid.2, getrlimit.2, getrusage.2, getsid.2, getsockname.2, getsockopt.2, gettid.2, gettimeofday.2, getuid.2, getunwind.2, init_module.2, inotify_add_watch.2, inotify_init.2, inotify_rm_watch.2, intro.2, io_cancel.2, io_destroy.2, io_getevents.2, io_setup.2, io_submit.2, ioctl_fat.2, ioctl_ficlonerange.2, ioctl_fideduperange.2, ioctl_tty.2, ioctl_userfaultfd.2, ioperm.2, iopl.2, ioprio_set.2, kcmp.2, kexec_load.2, keyctl.2, kill.2, link.2, listen.2, listxattr.2, llseek.2, lookup_dcookie.2, lseek.2, madvise.2, mbind.2, membarrier.2, memfd_create.2, migrate_pages.2, mincore.2, mkdir.2, mknod.2, mlock.2, mmap.2, mmap2.2, modify_ldt.2, move_pages.2, mprotect.2, mq_getsetattr.2, mremap.2, msgctl.2, msgget.2, msgop.2, msync.2, nanosleep.2, nfsservctl.2, nice.2, open_by_handle_at.2, outb.2, perf_event_open.2, perfmonctl.2, personality.2, pivot_root.2, pkey_alloc.2, poll.2, posix_fadvise.2, prctl.2, pread.2, process_vm_readv.2, ptrace.2, query_module.2, quotactl.2, read.2, readahead.2, readdir.2, readv.2, reboot.2, recv.2, recvmmsg.2, remap_file_pages.2, rename.2, request_key.2, restart_syscall.2, rt_sigqueueinfo.2, s390_pci_mmio_write.2, s390_runtime_instr.2, sched_get_priority_max.2, sched_rr_get_interval.2, sched_setaffinity.2, sched_setattr.2, sched_setparam.2, sched_setscheduler.2, sched_yield.2, seccomp.2, select.2, select_tut.2, semctl.2, semget.2, semop.2, send.2, sendfile.2, sendmmsg.2, set_mempolicy.2, set_thread_area.2, set_tid_address.2, seteuid.2, setfsgid.2, setfsuid.2, setgid.2, setns.2, setpgid.2, setresuid.2, setreuid.2, setsid.2, setuid.2, sgetmask.2, shmctl.2, shmget.2, shmop.2, sigaction.2, sigaltstack.2, sigpending.2, sigprocmask.2, sigreturn.2, sigsuspend.2, sigwaitinfo.2, socket.2, socketcall.2, socketpair.2, splice.2, spu_create.2, spu_run.2, stat.2, statfs.2, statx.2, subpage_prot.2, swapon.2, symlink.2, sync.2, sync_file_range.2, syscalls.2, sysctl.2, sysinfo.2, syslog.2, tee.2, time.2, timer_create.2, timer_getoverrun.2, timer_settime.2, timerfd_create.2, times.2, tkill.2, truncate.2, umask.2, umount.2, unimplemented.2, unlink.2, unshare.2, uselib.2, userfaultfd.2, utime.2, utimensat.2, vfork.2, vmsplice.2, wait.2, wait4.2, write.2: Formatting fix: replace blank lines with .PP/.IP
Blank lines shouldn't generally appear in *roff source (other
than in code examples), since they create large vertical
spaces between text blocks.
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2017-08-16 07:30:51 +00:00
|
|
|
.PP
|
2015-12-15 14:53:49 +00:00
|
|
|
.in +4n
|
execve.2, ioctl_console.2, ioctl_iflags.2, ioctl_ns.2, ioctl_userfaultfd.2, kcmp.2, kexec_load.2, keyctl.2, link.2, listxattr.2, membarrier.2, memfd_create.2, mmap.2, modify_ldt.2, mprotect.2, msgctl.2, nanosleep.2, open_by_handle_at.2, perf_event_open.2, poll.2, posix_fadvise.2, process_vm_readv.2, ptrace.2, query_module.2, quotactl.2, readdir.2, readv.2, recv.2, recvmmsg.2, request_key.2, sched_rr_get_interval.2, sched_setaffinity.2, sched_setattr.2, sched_setscheduler.2, seccomp.2, select.2, select_tut.2, semctl.2, semop.2, send.2, sendmmsg.2, set_thread_area.2, setns.2, shmctl.2, shmget.2, sigaction.2, sigaltstack.2, signal.2, sigwaitinfo.2, stat.2, statfs.2, statx.2, sync_file_range.2, syscall.2, sysctl.2, sysinfo.2, tee.2, timer_create.2, timer_settime.2, timerfd_create.2, unshare.2, userfaultfd.2, ustat.2, utime.2, utimensat.2, vmsplice.2, wait.2, adjtime.3, aio_init.3, backtrace.3, basename.3, bswap.3, btree.3, clock_getcpuclockid.3, cmsg.3, confstr.3, dbopen.3, dl_iterate_phdr.3, dladdr.3, dlinfo.3, dlopen.3, duplocale.3, encrypt.3, end.3, endian.3, err.3, errno.3, ether_aton.3, fgetgrent.3, fgetpwent.3, fmemopen.3, frexp.3, ftime.3, fts.3, getaddrinfo.3, getaddrinfo_a.3, getdate.3, getfsent.3, getgrent.3, getgrent_r.3, getgrnam.3, getgrouplist.3, gethostbyname.3, getifaddrs.3, getipnodebyname.3, getmntent.3, getnameinfo.3, getnetent.3, getopt.3, getprotoent.3, getprotoent_r.3, getpw.3, getpwent.3, getpwent_r.3, getpwnam.3, getrpcent.3, getservent.3, getservent_r.3, getspnam.3, getttyent.3, glob.3, gnu_get_libc_version.3, hash.3, hsearch.3, if_nameindex.3, inet.3, inet_net_pton.3, inet_pton.3, insque.3, isalpha.3, makecontext.3, mallinfo.3, malloc_info.3, mallopt.3, matherr.3, mbstowcs.3, mcheck.3, memchr.3, mq_getattr.3, mq_open.3, mq_receive.3, mq_send.3, mtrace.3, newlocale.3, ntp_gettime.3, posix_openpt.3, printf.3, pthread_attr_init.3, pthread_attr_setschedparam.3, pthread_cancel.3, pthread_cleanup_push.3, pthread_cleanup_push_defer_np.3, pthread_create.3, pthread_getattr_default_np.3, pthread_getattr_np.3, pthread_getcpuclockid.3, pthread_setname_np.3, pthread_setschedparam.3, pthread_sigmask.3, pthread_tryjoin_np.3, readdir.3, realpath.3, recno.3, regex.3, rpc.3, scanf.3, sched_getcpu.3, sem_wait.3, setaliasent.3, sigqueue.3, statvfs.3, strcat.3, strcpy.3, strftime.3, strtok.3, strtol.3, strverscmp.3, toupper.3, ttyslot.3, xdr.3, fuse.4, loop.4, rtc.4, st.4, acct.5, core.5, elf.5, slabinfo.5, aio.7, arp.7, capabilities.7, cgroup_namespaces.7, cgroups.7, ddp.7, fanotify.7, feature_test_macros.7, inode.7, inotify.7, ip.7, keyrings.7, locale.7, mount_namespaces.7, namespaces.7, netdevice.7, netlink.7, packet.7, pkeys.7, pthreads.7, sched.7, session-keyring.7, sock_diag.7, socket.7, spufs.7, udplite.7, unix.7, user_namespaces.7, vdso.7, x25.7, ld.so.8: Use consistent markup for code snippets
Change .nf/.fi to .EX/.EE
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2017-08-18 19:52:46 +00:00
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.EX
|
2015-12-13 13:17:43 +00:00
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#include <stdlib.h>
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static volatile int a, b;
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2015-12-15 14:53:49 +00:00
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static void
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fast_path(void)
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2015-12-13 13:17:43 +00:00
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{
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2015-12-15 14:53:49 +00:00
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int read_a, read_b;
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read_b = b;
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asm volatile ("mfence" : : : "memory");
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read_a = a;
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/* read_b == 1 implies read_a == 1. */
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if (read_b == 1 && read_a == 0)
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abort();
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2015-12-13 13:17:43 +00:00
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}
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2015-12-15 14:53:49 +00:00
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static void
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slow_path(void)
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2015-12-13 13:17:43 +00:00
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{
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2015-12-15 14:53:49 +00:00
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a = 1;
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asm volatile ("mfence" : : : "memory");
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b = 1;
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2015-12-13 13:17:43 +00:00
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}
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2015-12-15 14:53:49 +00:00
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int
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main(int argc, char **argv)
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2015-12-13 13:17:43 +00:00
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{
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2015-12-15 14:53:49 +00:00
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/*
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* Real applications would call fast_path() and slow_path()
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* from different threads. Call those from main() to keep
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* this example short.
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*/
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slow_path();
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fast_path();
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exit(EXIT_SUCCESS);
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2015-12-13 13:17:43 +00:00
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}
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execve.2, ioctl_console.2, ioctl_iflags.2, ioctl_ns.2, ioctl_userfaultfd.2, kcmp.2, kexec_load.2, keyctl.2, link.2, listxattr.2, membarrier.2, memfd_create.2, mmap.2, modify_ldt.2, mprotect.2, msgctl.2, nanosleep.2, open_by_handle_at.2, perf_event_open.2, poll.2, posix_fadvise.2, process_vm_readv.2, ptrace.2, query_module.2, quotactl.2, readdir.2, readv.2, recv.2, recvmmsg.2, request_key.2, sched_rr_get_interval.2, sched_setaffinity.2, sched_setattr.2, sched_setscheduler.2, seccomp.2, select.2, select_tut.2, semctl.2, semop.2, send.2, sendmmsg.2, set_thread_area.2, setns.2, shmctl.2, shmget.2, sigaction.2, sigaltstack.2, signal.2, sigwaitinfo.2, stat.2, statfs.2, statx.2, sync_file_range.2, syscall.2, sysctl.2, sysinfo.2, tee.2, timer_create.2, timer_settime.2, timerfd_create.2, unshare.2, userfaultfd.2, ustat.2, utime.2, utimensat.2, vmsplice.2, wait.2, adjtime.3, aio_init.3, backtrace.3, basename.3, bswap.3, btree.3, clock_getcpuclockid.3, cmsg.3, confstr.3, dbopen.3, dl_iterate_phdr.3, dladdr.3, dlinfo.3, dlopen.3, duplocale.3, encrypt.3, end.3, endian.3, err.3, errno.3, ether_aton.3, fgetgrent.3, fgetpwent.3, fmemopen.3, frexp.3, ftime.3, fts.3, getaddrinfo.3, getaddrinfo_a.3, getdate.3, getfsent.3, getgrent.3, getgrent_r.3, getgrnam.3, getgrouplist.3, gethostbyname.3, getifaddrs.3, getipnodebyname.3, getmntent.3, getnameinfo.3, getnetent.3, getopt.3, getprotoent.3, getprotoent_r.3, getpw.3, getpwent.3, getpwent_r.3, getpwnam.3, getrpcent.3, getservent.3, getservent_r.3, getspnam.3, getttyent.3, glob.3, gnu_get_libc_version.3, hash.3, hsearch.3, if_nameindex.3, inet.3, inet_net_pton.3, inet_pton.3, insque.3, isalpha.3, makecontext.3, mallinfo.3, malloc_info.3, mallopt.3, matherr.3, mbstowcs.3, mcheck.3, memchr.3, mq_getattr.3, mq_open.3, mq_receive.3, mq_send.3, mtrace.3, newlocale.3, ntp_gettime.3, posix_openpt.3, printf.3, pthread_attr_init.3, pthread_attr_setschedparam.3, pthread_cancel.3, pthread_cleanup_push.3, pthread_cleanup_push_defer_np.3, pthread_create.3, pthread_getattr_default_np.3, pthread_getattr_np.3, pthread_getcpuclockid.3, pthread_setname_np.3, pthread_setschedparam.3, pthread_sigmask.3, pthread_tryjoin_np.3, readdir.3, realpath.3, recno.3, regex.3, rpc.3, scanf.3, sched_getcpu.3, sem_wait.3, setaliasent.3, sigqueue.3, statvfs.3, strcat.3, strcpy.3, strftime.3, strtok.3, strtol.3, strverscmp.3, toupper.3, ttyslot.3, xdr.3, fuse.4, loop.4, rtc.4, st.4, acct.5, core.5, elf.5, slabinfo.5, aio.7, arp.7, capabilities.7, cgroup_namespaces.7, cgroups.7, ddp.7, fanotify.7, feature_test_macros.7, inode.7, inotify.7, ip.7, keyrings.7, locale.7, mount_namespaces.7, namespaces.7, netdevice.7, netlink.7, packet.7, pkeys.7, pthreads.7, sched.7, session-keyring.7, sock_diag.7, socket.7, spufs.7, udplite.7, unix.7, user_namespaces.7, vdso.7, x25.7, ld.so.8: Use consistent markup for code snippets
Change .nf/.fi to .EX/.EE
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2017-08-18 19:52:46 +00:00
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.EE
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2015-12-15 14:53:49 +00:00
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.in
|
_syscall.2, bpf.2, cacheflush.2, capget.2, chdir.2, chmod.2, chroot.2, clock_getres.2, clock_nanosleep.2, clone.2, close.2, connect.2, copy_file_range.2, create_module.2, delete_module.2, dup.2, epoll_create.2, epoll_ctl.2, epoll_wait.2, eventfd.2, execve.2, execveat.2, fallocate.2, flock.2, fork.2, fsync.2, futex.2, futimesat.2, get_kernel_syms.2, get_mempolicy.2, get_robust_list.2, getcpu.2, getdents.2, getdomainname.2, getgid.2, getgroups.2, gethostname.2, getitimer.2, getpagesize.2, getpeername.2, getpriority.2, getrandom.2, getresuid.2, getrlimit.2, getrusage.2, getsid.2, getsockname.2, getsockopt.2, gettid.2, gettimeofday.2, getuid.2, getunwind.2, init_module.2, inotify_add_watch.2, inotify_init.2, inotify_rm_watch.2, intro.2, io_cancel.2, io_destroy.2, io_getevents.2, io_setup.2, io_submit.2, ioctl_fat.2, ioctl_ficlonerange.2, ioctl_fideduperange.2, ioctl_tty.2, ioctl_userfaultfd.2, ioperm.2, iopl.2, ioprio_set.2, kcmp.2, kexec_load.2, keyctl.2, kill.2, link.2, listen.2, listxattr.2, llseek.2, lookup_dcookie.2, lseek.2, madvise.2, mbind.2, membarrier.2, memfd_create.2, migrate_pages.2, mincore.2, mkdir.2, mknod.2, mlock.2, mmap.2, mmap2.2, modify_ldt.2, move_pages.2, mprotect.2, mq_getsetattr.2, mremap.2, msgctl.2, msgget.2, msgop.2, msync.2, nanosleep.2, nfsservctl.2, nice.2, open_by_handle_at.2, outb.2, perf_event_open.2, perfmonctl.2, personality.2, pivot_root.2, pkey_alloc.2, poll.2, posix_fadvise.2, prctl.2, pread.2, process_vm_readv.2, ptrace.2, query_module.2, quotactl.2, read.2, readahead.2, readdir.2, readv.2, reboot.2, recv.2, recvmmsg.2, remap_file_pages.2, rename.2, request_key.2, restart_syscall.2, rt_sigqueueinfo.2, s390_pci_mmio_write.2, s390_runtime_instr.2, sched_get_priority_max.2, sched_rr_get_interval.2, sched_setaffinity.2, sched_setattr.2, sched_setparam.2, sched_setscheduler.2, sched_yield.2, seccomp.2, select.2, select_tut.2, semctl.2, semget.2, semop.2, send.2, sendfile.2, sendmmsg.2, set_mempolicy.2, set_thread_area.2, set_tid_address.2, seteuid.2, setfsgid.2, setfsuid.2, setgid.2, setns.2, setpgid.2, setresuid.2, setreuid.2, setsid.2, setuid.2, sgetmask.2, shmctl.2, shmget.2, shmop.2, sigaction.2, sigaltstack.2, sigpending.2, sigprocmask.2, sigreturn.2, sigsuspend.2, sigwaitinfo.2, socket.2, socketcall.2, socketpair.2, splice.2, spu_create.2, spu_run.2, stat.2, statfs.2, statx.2, subpage_prot.2, swapon.2, symlink.2, sync.2, sync_file_range.2, syscalls.2, sysctl.2, sysinfo.2, syslog.2, tee.2, time.2, timer_create.2, timer_getoverrun.2, timer_settime.2, timerfd_create.2, times.2, tkill.2, truncate.2, umask.2, umount.2, unimplemented.2, unlink.2, unshare.2, uselib.2, userfaultfd.2, utime.2, utimensat.2, vfork.2, vmsplice.2, wait.2, wait4.2, write.2: Formatting fix: replace blank lines with .PP/.IP
Blank lines shouldn't generally appear in *roff source (other
than in code examples), since they create large vertical
spaces between text blocks.
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2017-08-16 07:30:51 +00:00
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.PP
|
2015-12-15 14:53:49 +00:00
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The code above transformed to use
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.BR membarrier ()
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becomes:
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_syscall.2, bpf.2, cacheflush.2, capget.2, chdir.2, chmod.2, chroot.2, clock_getres.2, clock_nanosleep.2, clone.2, close.2, connect.2, copy_file_range.2, create_module.2, delete_module.2, dup.2, epoll_create.2, epoll_ctl.2, epoll_wait.2, eventfd.2, execve.2, execveat.2, fallocate.2, flock.2, fork.2, fsync.2, futex.2, futimesat.2, get_kernel_syms.2, get_mempolicy.2, get_robust_list.2, getcpu.2, getdents.2, getdomainname.2, getgid.2, getgroups.2, gethostname.2, getitimer.2, getpagesize.2, getpeername.2, getpriority.2, getrandom.2, getresuid.2, getrlimit.2, getrusage.2, getsid.2, getsockname.2, getsockopt.2, gettid.2, gettimeofday.2, getuid.2, getunwind.2, init_module.2, inotify_add_watch.2, inotify_init.2, inotify_rm_watch.2, intro.2, io_cancel.2, io_destroy.2, io_getevents.2, io_setup.2, io_submit.2, ioctl_fat.2, ioctl_ficlonerange.2, ioctl_fideduperange.2, ioctl_tty.2, ioctl_userfaultfd.2, ioperm.2, iopl.2, ioprio_set.2, kcmp.2, kexec_load.2, keyctl.2, kill.2, link.2, listen.2, listxattr.2, llseek.2, lookup_dcookie.2, lseek.2, madvise.2, mbind.2, membarrier.2, memfd_create.2, migrate_pages.2, mincore.2, mkdir.2, mknod.2, mlock.2, mmap.2, mmap2.2, modify_ldt.2, move_pages.2, mprotect.2, mq_getsetattr.2, mremap.2, msgctl.2, msgget.2, msgop.2, msync.2, nanosleep.2, nfsservctl.2, nice.2, open_by_handle_at.2, outb.2, perf_event_open.2, perfmonctl.2, personality.2, pivot_root.2, pkey_alloc.2, poll.2, posix_fadvise.2, prctl.2, pread.2, process_vm_readv.2, ptrace.2, query_module.2, quotactl.2, read.2, readahead.2, readdir.2, readv.2, reboot.2, recv.2, recvmmsg.2, remap_file_pages.2, rename.2, request_key.2, restart_syscall.2, rt_sigqueueinfo.2, s390_pci_mmio_write.2, s390_runtime_instr.2, sched_get_priority_max.2, sched_rr_get_interval.2, sched_setaffinity.2, sched_setattr.2, sched_setparam.2, sched_setscheduler.2, sched_yield.2, seccomp.2, select.2, select_tut.2, semctl.2, semget.2, semop.2, send.2, sendfile.2, sendmmsg.2, set_mempolicy.2, set_thread_area.2, set_tid_address.2, seteuid.2, setfsgid.2, setfsuid.2, setgid.2, setns.2, setpgid.2, setresuid.2, setreuid.2, setsid.2, setuid.2, sgetmask.2, shmctl.2, shmget.2, shmop.2, sigaction.2, sigaltstack.2, sigpending.2, sigprocmask.2, sigreturn.2, sigsuspend.2, sigwaitinfo.2, socket.2, socketcall.2, socketpair.2, splice.2, spu_create.2, spu_run.2, stat.2, statfs.2, statx.2, subpage_prot.2, swapon.2, symlink.2, sync.2, sync_file_range.2, syscalls.2, sysctl.2, sysinfo.2, syslog.2, tee.2, time.2, timer_create.2, timer_getoverrun.2, timer_settime.2, timerfd_create.2, times.2, tkill.2, truncate.2, umask.2, umount.2, unimplemented.2, unlink.2, unshare.2, uselib.2, userfaultfd.2, utime.2, utimensat.2, vfork.2, vmsplice.2, wait.2, wait4.2, write.2: Formatting fix: replace blank lines with .PP/.IP
Blank lines shouldn't generally appear in *roff source (other
than in code examples), since they create large vertical
spaces between text blocks.
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2017-08-16 07:30:51 +00:00
|
|
|
.PP
|
2015-12-15 14:53:49 +00:00
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.in +4n
|
execve.2, ioctl_console.2, ioctl_iflags.2, ioctl_ns.2, ioctl_userfaultfd.2, kcmp.2, kexec_load.2, keyctl.2, link.2, listxattr.2, membarrier.2, memfd_create.2, mmap.2, modify_ldt.2, mprotect.2, msgctl.2, nanosleep.2, open_by_handle_at.2, perf_event_open.2, poll.2, posix_fadvise.2, process_vm_readv.2, ptrace.2, query_module.2, quotactl.2, readdir.2, readv.2, recv.2, recvmmsg.2, request_key.2, sched_rr_get_interval.2, sched_setaffinity.2, sched_setattr.2, sched_setscheduler.2, seccomp.2, select.2, select_tut.2, semctl.2, semop.2, send.2, sendmmsg.2, set_thread_area.2, setns.2, shmctl.2, shmget.2, sigaction.2, sigaltstack.2, signal.2, sigwaitinfo.2, stat.2, statfs.2, statx.2, sync_file_range.2, syscall.2, sysctl.2, sysinfo.2, tee.2, timer_create.2, timer_settime.2, timerfd_create.2, unshare.2, userfaultfd.2, ustat.2, utime.2, utimensat.2, vmsplice.2, wait.2, adjtime.3, aio_init.3, backtrace.3, basename.3, bswap.3, btree.3, clock_getcpuclockid.3, cmsg.3, confstr.3, dbopen.3, dl_iterate_phdr.3, dladdr.3, dlinfo.3, dlopen.3, duplocale.3, encrypt.3, end.3, endian.3, err.3, errno.3, ether_aton.3, fgetgrent.3, fgetpwent.3, fmemopen.3, frexp.3, ftime.3, fts.3, getaddrinfo.3, getaddrinfo_a.3, getdate.3, getfsent.3, getgrent.3, getgrent_r.3, getgrnam.3, getgrouplist.3, gethostbyname.3, getifaddrs.3, getipnodebyname.3, getmntent.3, getnameinfo.3, getnetent.3, getopt.3, getprotoent.3, getprotoent_r.3, getpw.3, getpwent.3, getpwent_r.3, getpwnam.3, getrpcent.3, getservent.3, getservent_r.3, getspnam.3, getttyent.3, glob.3, gnu_get_libc_version.3, hash.3, hsearch.3, if_nameindex.3, inet.3, inet_net_pton.3, inet_pton.3, insque.3, isalpha.3, makecontext.3, mallinfo.3, malloc_info.3, mallopt.3, matherr.3, mbstowcs.3, mcheck.3, memchr.3, mq_getattr.3, mq_open.3, mq_receive.3, mq_send.3, mtrace.3, newlocale.3, ntp_gettime.3, posix_openpt.3, printf.3, pthread_attr_init.3, pthread_attr_setschedparam.3, pthread_cancel.3, pthread_cleanup_push.3, pthread_cleanup_push_defer_np.3, pthread_create.3, pthread_getattr_default_np.3, pthread_getattr_np.3, pthread_getcpuclockid.3, pthread_setname_np.3, pthread_setschedparam.3, pthread_sigmask.3, pthread_tryjoin_np.3, readdir.3, realpath.3, recno.3, regex.3, rpc.3, scanf.3, sched_getcpu.3, sem_wait.3, setaliasent.3, sigqueue.3, statvfs.3, strcat.3, strcpy.3, strftime.3, strtok.3, strtol.3, strverscmp.3, toupper.3, ttyslot.3, xdr.3, fuse.4, loop.4, rtc.4, st.4, acct.5, core.5, elf.5, slabinfo.5, aio.7, arp.7, capabilities.7, cgroup_namespaces.7, cgroups.7, ddp.7, fanotify.7, feature_test_macros.7, inode.7, inotify.7, ip.7, keyrings.7, locale.7, mount_namespaces.7, namespaces.7, netdevice.7, netlink.7, packet.7, pkeys.7, pthreads.7, sched.7, session-keyring.7, sock_diag.7, socket.7, spufs.7, udplite.7, unix.7, user_namespaces.7, vdso.7, x25.7, ld.so.8: Use consistent markup for code snippets
Change .nf/.fi to .EX/.EE
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2017-08-18 19:52:46 +00:00
|
|
|
.EX
|
2015-12-13 13:17:43 +00:00
|
|
|
#define _GNU_SOURCE
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|
#include <stdlib.h>
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#include <stdio.h>
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|
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#include <unistd.h>
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#include <sys/syscall.h>
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|
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#include <linux/membarrier.h>
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static volatile int a, b;
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2015-12-15 14:53:49 +00:00
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static int
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membarrier(int cmd, int flags)
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2015-12-13 13:17:43 +00:00
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{
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2015-12-15 14:53:49 +00:00
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return syscall(__NR_membarrier, cmd, flags);
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2015-12-13 13:17:43 +00:00
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}
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2015-12-15 14:53:49 +00:00
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static int
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init_membarrier(void)
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2015-12-13 13:17:43 +00:00
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{
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2015-12-15 14:53:49 +00:00
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int ret;
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/* Check that membarrier() is supported. */
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ret = membarrier(MEMBARRIER_CMD_QUERY, 0);
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if (ret < 0) {
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perror("membarrier");
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return \-1;
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}
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if (!(ret & MEMBARRIER_CMD_SHARED)) {
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fprintf(stderr,
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"membarrier does not support MEMBARRIER_CMD_SHARED\\n");
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return \-1;
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}
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return 0;
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2015-12-13 13:17:43 +00:00
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}
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2015-12-15 14:53:49 +00:00
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static void
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fast_path(void)
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2015-12-13 13:17:43 +00:00
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{
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2015-12-15 14:53:49 +00:00
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int read_a, read_b;
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read_b = b;
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asm volatile ("" : : : "memory");
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read_a = a;
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/* read_b == 1 implies read_a == 1. */
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if (read_b == 1 && read_a == 0)
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abort();
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2015-12-13 13:17:43 +00:00
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}
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2015-12-15 14:53:49 +00:00
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static void
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slow_path(void)
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2015-12-13 13:17:43 +00:00
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{
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2015-12-15 14:53:49 +00:00
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a = 1;
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membarrier(MEMBARRIER_CMD_SHARED, 0);
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b = 1;
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2015-12-13 13:17:43 +00:00
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}
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2015-12-15 14:53:49 +00:00
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int
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main(int argc, char **argv)
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2015-12-13 13:17:43 +00:00
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{
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2015-12-15 14:53:49 +00:00
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if (init_membarrier())
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exit(EXIT_FAILURE);
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/*
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* Real applications would call fast_path() and slow_path()
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* from different threads. Call those from main() to keep
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* this example short.
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*/
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slow_path();
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fast_path();
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exit(EXIT_SUCCESS);
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2015-12-13 13:17:43 +00:00
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}
|
execve.2, ioctl_console.2, ioctl_iflags.2, ioctl_ns.2, ioctl_userfaultfd.2, kcmp.2, kexec_load.2, keyctl.2, link.2, listxattr.2, membarrier.2, memfd_create.2, mmap.2, modify_ldt.2, mprotect.2, msgctl.2, nanosleep.2, open_by_handle_at.2, perf_event_open.2, poll.2, posix_fadvise.2, process_vm_readv.2, ptrace.2, query_module.2, quotactl.2, readdir.2, readv.2, recv.2, recvmmsg.2, request_key.2, sched_rr_get_interval.2, sched_setaffinity.2, sched_setattr.2, sched_setscheduler.2, seccomp.2, select.2, select_tut.2, semctl.2, semop.2, send.2, sendmmsg.2, set_thread_area.2, setns.2, shmctl.2, shmget.2, sigaction.2, sigaltstack.2, signal.2, sigwaitinfo.2, stat.2, statfs.2, statx.2, sync_file_range.2, syscall.2, sysctl.2, sysinfo.2, tee.2, timer_create.2, timer_settime.2, timerfd_create.2, unshare.2, userfaultfd.2, ustat.2, utime.2, utimensat.2, vmsplice.2, wait.2, adjtime.3, aio_init.3, backtrace.3, basename.3, bswap.3, btree.3, clock_getcpuclockid.3, cmsg.3, confstr.3, dbopen.3, dl_iterate_phdr.3, dladdr.3, dlinfo.3, dlopen.3, duplocale.3, encrypt.3, end.3, endian.3, err.3, errno.3, ether_aton.3, fgetgrent.3, fgetpwent.3, fmemopen.3, frexp.3, ftime.3, fts.3, getaddrinfo.3, getaddrinfo_a.3, getdate.3, getfsent.3, getgrent.3, getgrent_r.3, getgrnam.3, getgrouplist.3, gethostbyname.3, getifaddrs.3, getipnodebyname.3, getmntent.3, getnameinfo.3, getnetent.3, getopt.3, getprotoent.3, getprotoent_r.3, getpw.3, getpwent.3, getpwent_r.3, getpwnam.3, getrpcent.3, getservent.3, getservent_r.3, getspnam.3, getttyent.3, glob.3, gnu_get_libc_version.3, hash.3, hsearch.3, if_nameindex.3, inet.3, inet_net_pton.3, inet_pton.3, insque.3, isalpha.3, makecontext.3, mallinfo.3, malloc_info.3, mallopt.3, matherr.3, mbstowcs.3, mcheck.3, memchr.3, mq_getattr.3, mq_open.3, mq_receive.3, mq_send.3, mtrace.3, newlocale.3, ntp_gettime.3, posix_openpt.3, printf.3, pthread_attr_init.3, pthread_attr_setschedparam.3, pthread_cancel.3, pthread_cleanup_push.3, pthread_cleanup_push_defer_np.3, pthread_create.3, pthread_getattr_default_np.3, pthread_getattr_np.3, pthread_getcpuclockid.3, pthread_setname_np.3, pthread_setschedparam.3, pthread_sigmask.3, pthread_tryjoin_np.3, readdir.3, realpath.3, recno.3, regex.3, rpc.3, scanf.3, sched_getcpu.3, sem_wait.3, setaliasent.3, sigqueue.3, statvfs.3, strcat.3, strcpy.3, strftime.3, strtok.3, strtol.3, strverscmp.3, toupper.3, ttyslot.3, xdr.3, fuse.4, loop.4, rtc.4, st.4, acct.5, core.5, elf.5, slabinfo.5, aio.7, arp.7, capabilities.7, cgroup_namespaces.7, cgroups.7, ddp.7, fanotify.7, feature_test_macros.7, inode.7, inotify.7, ip.7, keyrings.7, locale.7, mount_namespaces.7, namespaces.7, netdevice.7, netlink.7, packet.7, pkeys.7, pthreads.7, sched.7, session-keyring.7, sock_diag.7, socket.7, spufs.7, udplite.7, unix.7, user_namespaces.7, vdso.7, x25.7, ld.so.8: Use consistent markup for code snippets
Change .nf/.fi to .EX/.EE
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2017-08-18 19:52:46 +00:00
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.EE
|
2015-12-15 14:53:49 +00:00
|
|
|
.in
|