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Author SHA1 Message Date
Jakub Wilk f6615c426b futex.2: tfix 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-30 20:35:30 +01:00
Michael Kerrisk cd175805de futex.2: srcfix 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-30 13:57:02 +01:00
Michael Kerrisk e24fbf1098 Removed trailing white space at end of lines 2015-12-29 13:51:32 +01:00
Michael Kerrisk 29b41e747f accept.2, acct.2, bind.2, clock_getres.2, connect.2, dup.2, epoll_create.2, eventfd.2, execve.2, fanotify_init.2, fcntl.2, fork.2, futex.2, get_robust_list.2, getcpu.2, getpeername.2, getrlimit.2, getsockname.2, getsockopt.2, gettimeofday.2, inotify_init.2, listen.2, membarrier.2, memfd_create.2, mlock.2, mmap.2, personality.2, pipe.2, poll.2, recv.2, send.2, sendfile.2, shmget.2, shutdown.2, sigreturn.2, socket.2, socketcall.2, socketpair.2, spu_create.2, swapon.2, time.2, timerfd_create.2, uselib.2, dlerror.3, dlopen.3, drand48.3, errno.3, fnmatch.3, getgrent.3, getgrnam.3, getlogin.3, getpwent.3, getpwnam.3, iconv.3, mq_open.3, opendir.3, random_r.3, sem_open.3, shm_open.3, tmpfile.3, tzset.3, random.4, fanotify.7, futex.7, vdso.7, ld.so.8: tstamp 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-29 13:48:42 +01:00
Michael Kerrisk e258766bf4 accept.2, acct.2, epoll_create.2, execve.2, futex.2, inotify_init.2, mmap.2, open.2, pipe.2, shmget.2, socket.2, socketpair.2, spu_create.2, swapon.2, uselib.2, getgrent.3, getgrnam.3, getlogin.3, getpwent.3, getpwnam.3, mq_open.3, opendir.3, sem_open.3, shm_open.3, tmpfile.3, fanotify.7: ERRORS: standardize text for ENFILE error 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-27 17:10:23 +01:00
Michael Kerrisk 8adaf0a794 futex.2: Minor wording tweaks after comments from Darren Hart 
Reported-by: Darren Hart <dvhart@infradead.org>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-26 09:02:35 +01:00
Michael Kerrisk 2af84f99ad futex.2: wfix 
Reported-by: Jonathan Wakely <jwakely@redhat.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-19 06:22:47 +01:00
Michael Kerrisk bc54ed38c5 futex.2: Minor wording fixes 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-19 06:22:11 +01:00
Michael Kerrisk 5e1456d4c9 futex.2: Replace "bitset" by "bit mask" 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-19 06:22:02 +01:00
Michael Kerrisk da894b18a8 futex.2: Fixes after comments from Darren Hart 
Reported-by: Darren Hart <dvhart@infradead.org>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-17 06:43:53 +01:00
Michael Kerrisk 0fb87d16ac futex.2: Clarify "total ordering" a little 
Comments from Davidlohr:

    So there are two things here regarding ordering. One is the
    most obvious which is ordered due to the taking/dropping the
    hb spinlock. Secondly, its the cases which Peter brought up
    a while ago that involves atomic futex ops futex_atomic_*(),
    which do not have clearly defined semantics, and you get
    inconsistencies with certain archs (tile being the worst
    iirc).

    But anyway, the important thing users need to know about is
    that the atomic futex operation must be totally ordered wrt
    any other user tasks that are trying to access that address.
    This is not necessarily the case for kernel ops. Peter
    illustrates this nicely with lock stealing example; (see
    https://lkml.org/lkml/2015/8/26/596).

    Internally, I believe we decided that making it fully ordered
    (as opposed to making use of implicit barriers for
    ACQUIRE/RELEASE), so you'd end up having an MB ll/sc MB kind of
    setup.

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
Reported-by: Davidlohr Bueso <dave@stgolabs.net>
 2015-12-17 06:43:40 +01:00
Michael Kerrisk 3fbb1be115 futex.2: Minor fixes after comments from Torvald Riegel 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 17:00:04 +01:00
Michael Kerrisk 57f2d48bc1 futex.2: tfix 
Reported-by: Alexander Monakov <amonakov@ispras.ru>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 16:47:52 +01:00
Michael Kerrisk ee65b0e842 futex.2: srcfix (notes from conversation with tglx) 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:49 +01:00
Michael Kerrisk c3f4c0196a futex.2: tfix 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:49 +01:00
Michael Kerrisk d0442d147d futex.2: wfix 
Reported-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:49 +01:00
Michael Kerrisk 1d09c1500f futex.2: Fixes after feedback from Thomas Gleixner 
Reported-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:49 +01:00
Michael Kerrisk ca4e5b2b99 futex.2: Minor wording fixes 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:49 +01:00
Michael Kerrisk 601399f31f futex.2: Improvements after comments from Darren Hart 
Reported-by: Darren Hart <dvhart@infradead.org>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:49 +01:00
Michael Kerrisk adc89a976e futex.2: ffix 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:49 +01:00
Michael Kerrisk 41b6c6a080 futex.2: srcfix: FIXME 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:49 +01:00
Michael Kerrisk c3875d1d3a futex.2: Fixes after review comments from Thomas Gleixner 
Reported-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:49 +01:00
Michael Kerrisk 30239c10a8 futex.2: Various fixes after comments from Thomas Gleixner 
Reported-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:49 +01:00
Michael Kerrisk aab5ca4b64 futex.2: wfix 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:49 +01:00
Michael Kerrisk f0a9e8f4ce futex.2: tfix 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:49 +01:00
Michael Kerrisk 39e9b2e1e4 futex.2: wfix 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:49 +01:00
Michael Kerrisk 9cee832c40 futex.2: wfix 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:49 +01:00
Michael Kerrisk ac89487996 futex.2: Fixes after review comments from Thomas Gleixner 
Reported-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:49 +01:00
Michael Kerrisk dcb410c3c8 futex.2: tfix 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:49 +01:00
Michael Kerrisk 627b50ce7c futex.2: Elaborate on why "requeue" operations can be preferable to FUTEX_WAKE 
Cowritten-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:48 +01:00
Michael Kerrisk 8297383e9e futex.2: Clean-ups and FIXME removeal after feedback from Thomas Gleixner 
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:48 +01:00
Michael Kerrisk 27dd3a6e79 futex.2: Remove warning that FUTEX_REQUEUE is broken 
Darren Hart pointed me to the comments from Rich Felker
that there are valid use cases for FUTEX_REQUEUE.

    From: Rich Felker <dalias@libc.org>
    Date: Wed, 29 Oct 2014 22:43:17 -0400
    To: Darren Hart <dvhart@infradead.org>
    Cc: GLIBC Devel <libc-alpha@sourceware.org>, ...
    Subject: Re: Add futex wrapper to glibc?

    On Wed, Oct 29, 2014 at 06:59:15PM -0700, Darren Hart wrote:
    [...]
    > I wonder though... can we not wrap FUTEX_REQUEUE? It's fundamentally
    > broken.  FUTEX_CMP_REQUEUE should *always* be used instead. The glibc
    > wrapper is one way to encourage developers to do the right thing
    > (don't expose the bad op in the header).

    You're mistaken here. There are plenty of valid ways to use
    FUTEX_REQUEUE - for example if the calling thread is requeuing the
    target(s) to a lock that the calling thread owns. Just because it
    doesn't meet the needs of the way glibc was using it internally
    doesn't mean it's useless for other applications.

Reported-by: Darren Hart <dvhart@infradead.org>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:48 +01:00
Michael Kerrisk da56650ae4 futex.2: srcfix 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:48 +01:00
Michael Kerrisk fd1056148b futex.2: Minor wording fixes 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:48 +01:00
Michael Kerrisk 55f9e85ead futex.2: Minor wording fixes 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:48 +01:00
Michael Kerrisk b0f35fbb09 futex.2: tfix 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:48 +01:00
Michael Kerrisk c0dc758efd futex.2: Rewrap some source lines (no content changes) 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:48 +01:00
Michael Kerrisk 9d32a39b82 futex.2: Minor wording fixes 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:48 +01:00
Michael Kerrisk d45f244c6d futex.2: Minor wording fixes 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:48 +01:00
Michael Kerrisk 7e8dcabcb1 futex.2: Reword paragraph describing futex word 
Reported-by: Davidlohr Bueso <dave@stgolabs.net>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:48 +01:00
Michael Kerrisk 02f7b623c9 futex.2: NOTES: futexes are also used to implement read-write locks and barriers 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:48 +01:00
Michael Kerrisk e0074751c9 futex.2: SEE ALSO: add pthread_mutexattr_getprotocol(3) 
Reported-by: Davidlohr Bueso <dave@stgolabs.net>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:48 +01:00
Michael Kerrisk 36a90a75ce futex.2: wfix 
Reported-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:48 +01:00
Michael Kerrisk d6bb5a38db futex.2: Tidy up some FIXMEs 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:48 +01:00
Michael Kerrisk cf44281c66 futex.2: Point out that futexes are used to implement higher-level abstractions 
Reported-by: Thomas Gleixner <tglx@linutronix.de>
Reported-by: Torvald Riegel <triegel@redhat.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:48 +01:00
Michael Kerrisk 78bbcd9faf futex.2: Remove an obsolete FIXME 
Reviewed-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:48 +01:00
Michael Kerrisk cabee29d5e futex.2: tfix 
Reported-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:48 +01:00
Michael Kerrisk e61abc2018 futex.2: tfix 
Reported-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:48 +01:00
Michael Kerrisk a5c5a06aba futex.2: Clarify return value details 
Reporte-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:48 +01:00
Michael Kerrisk 943ccc5228 futex.2: Remove detail about kernel internals 
As commented on by Davidlohr Bueso:

    This to me reads a bit too much into the kernel (fastpath,
    refcnt, vmas). Why not just mention that it avoids overhead
    in the kernel or something? I don't recall any manpage
    mentioning such details, but I could be wrong.

Reported-by: Davidlohr Bueso <dave@stgolabs.net>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:48 +01:00