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Torvald Riegel 4b35dc5dab futex.2: Terminology fixes 
Here is the result of a first pass over futex.2.  I tried to
do nothing that is too controversial.  I tried to apply the
terminology that at least Darren and I had in mind
consistently; but please check again.

The major changes are in how futexes are described in the
introductory parts of the page.  I hope it's easier to understand
now.  I've also tried to add some more precision to the the
description of the synchronization semantics (e.g., it makes a
difference whether we claim something is atomic (without further
qualification), or just atomic wrt.  other futex operations).
In some cases, that adds some verbosity to the text -- but I
believe that this is worth the clarity and consistency in using
terms, for example.

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:47 +01:00
Michael Kerrisk 77da5febea futex.2: tfix 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:47 +01:00
Michael Kerrisk 305cc4153b futex.2: Add EXAMPLE program 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:47 +01:00
Michael Kerrisk 02182e7c8c futex.2: srcfix: FIXME 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:47 +01:00
Michael Kerrisk 1af427a43d futex.2: srcfix 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:47 +01:00
Michael Kerrisk 47f5c4baf5 futex.2: srcfix: FIXME 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:47 +01:00
Michael Kerrisk f529fd2013 futex Since Linux 2.6.22, EINTR can no longer occur on spurious wakeup 
As reported by Rich Felker:

    I see no code in the kernel whereby a "spurious wakeup",
    or anything other than interruption by a signal handler
    that's not SA_RESTART, can cause futex to fail with EINTR.
    In general, overloading of EINTR and/or spurious EINTRs
    from a syscall make it impossible to use that syscall for
    implementing any function where EINTR is a mandatory
    failure on interruption-by-signal, since there is no way
    for userspace to distinguish whether the EINTR occurred
    as a result of an interrupting signal or some other
    reason. The kernel folks have gone to great lengths to fix
    spurious EINTRs (see signal(7) for history), especially by
    non-interrupting signal handlers, including in futex, and
    allowing EINTR here would be contrary to that goal.

     It's my belief that the "or a spurious wakeup" text should
     simply be removed.

     The reason I'm raising this topic is its relevance to a
     thread on libc-alpha:

     [RFC] mutex destruction (#13690): problem description and workarounds

The bug and mailing list discussions to which Rich refers are:
     https://sourceware.org/bugzilla/show_bug.cgi?id=13690
     https://sourceware.org/ml/libc-alpha/2014-12/threads.html#0001

Torvald Riegel also reported the same issue, and Thomas Gleixner
noted that the "EINTR on spurious wakeup" behavior went away in
Linux 2.6.22. See the LKML thread, "futex() man page update help
request", Jan 2015:
http://thread.gmane.org/gmane.linux.kernel/1703405/focus=7734

Reported-by: Rich Felker <dalias@libc.org>
Reported-by: Torvald Riegel <triegel@redhat.com>
Reported-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Michael Kerrisk <mtknpages@gmail.com>
 2015-12-15 14:39:47 +01:00
Michael Kerrisk 9732dd8b3f futex.2: Various fixes after review from Davidlohr Bueso 
Reviewed-by: Davidlohr Bueso <dave@stgolabs.net>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:47 +01:00
Michael Kerrisk 2abcba676a futex.2: Remove FUTEX_REQUEUE EINVAL error case 
Thomas Gleixner confirmed my reading that this case does
not apply.

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:47 +01:00
Michael Kerrisk 9e2b90ee42 futex.2: Add an attmpt at a defintion of PI-aware futexes 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:47 +01:00
Michael Kerrisk 7bd3ffbc52 futex.2: srcfix 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:47 +01:00
Michael Kerrisk d9d5be6bea futex.2: tfix 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:46 +01:00
Michael Kerrisk 809ca3ae64 futex.2: Note that the kernel only "knows" about a futex in the contended case 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:46 +01:00
Michael Kerrisk a663ca5a12 futex.2: Add some subsection headings 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:46 +01:00
Michael Kerrisk e219551457 futex.2: srcfix 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:46 +01:00
Michael Kerrisk ed44c7c071 futex.2: Rewrite text on intended users of futexes 
Eliminate some redundant text.

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:46 +01:00
Michael Kerrisk abb571e8b7 futex.2: Add text on pairing of FUTEX_WAIT_REQUEUE_PI + FUTEX_CMP_REQUEUE_PI 
Reported-by: Darren Hart <dvhart@linux.intel.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:46 +01:00
Michael Kerrisk f1d2171d38 futex.2: srcfix 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:46 +01:00
Michael Kerrisk bdc5957afa futex.2: Process/thread rewordings 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:46 +01:00
Michael Kerrisk a59564304a futex.2: srcfix 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:46 +01:00
Michael Kerrisk 6700de2462 futex.2: tfix 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:46 +01:00
Michael Kerrisk 7d20efd7b0 futex.2: Add overview of priority inheritance 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:46 +01:00
Michael Kerrisk b565548bfa futex.2: Add brief description of the priority inversion problem 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:46 +01:00
Michael Kerrisk dd003bef7a futex.2: srcfix: FIXME 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:46 +01:00
Michael Kerrisk 8fe019c733 futex.2: SEE ALSO: add Documentation/robust-futex-ABI.txt 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:46 +01:00
Michael Kerrisk 4cf9289452 futex.2: tfix 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:46 +01:00
Michael Kerrisk baf0f1f470 futex.2: Note that syscall() must be employed 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:46 +01:00
Michael Kerrisk 4c2222812b futex.2: SEEL ALSO: add author details + other minor tweaks 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:46 +01:00
Michael Kerrisk 939ca89f38 futex.2: wfix 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:46 +01:00
Michael Kerrisk d4ba43283d futex.2: wfix 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:46 +01:00
Michael Kerrisk a282e5b050 futex.2: wfix 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:46 +01:00
Michael Kerrisk 30ebf7b4a1 futex.2: srcfix: FIXME 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:46 +01:00
Michael Kerrisk 7f315ae3e5 futex.2: ffix 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:46 +01:00
Michael Kerrisk 43d16602be futex.2: srcfix: FIXME 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:46 +01:00
Michael Kerrisk 64191e8f09 futex.2: srcfix: FIXME 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:46 +01:00
Michael Kerrisk f2bf5121d5 futex.2: srcfix 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:46 +01:00
Michael Kerrisk 53ba4030d1 futex.2: grfix 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:46 +01:00
Michael Kerrisk 4e566b1ebd futex.2: wfix 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:45 +01:00
Michael Kerrisk e45f973525 futex.2: Clarify that FUTEX_PRIVATE_FLAG relates to *thread* synchronization 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:45 +01:00
Michael Kerrisk f19904c01c futex.2: wfix: mention "virtual" when talking about memory addreses 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:45 +01:00
Michael Kerrisk 70b06b9033 futex.2: srcfix 
Various minor fixes to source

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:45 +01:00
Michael Kerrisk a59fca7505 futex.2: wfix 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:45 +01:00
Michael Kerrisk 21b060bae6 futex.2: wfix 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:45 +01:00
Michael Kerrisk 5d67b190a1 futex.2: srcfix: FIXME 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:45 +01:00
Michael Kerrisk f0c0d61cd8 futex.2: ERRORS: add EINVAL case for FUTEX_CMP_REQUEUE_PI 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:45 +01:00
Michael Kerrisk 99c0ac69d9 futex.2: srcfix: FIXME 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:45 +01:00
Michael Kerrisk 9786b3ca15 futex.2: ERRORS: Add EINVAL case for FUTEX_CMP_REQUEUE_PI 
Reported-by: Darren Hart <dvhart@linux.intel.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:45 +01:00
Michael Kerrisk 75299c8d17 futex.2: Fix EINVAL description for FUTEX_CMP_REQUEUE_PI 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:45 +01:00
Michael Kerrisk 6fbeb8f4a0 futex.2: Minor improvement to FUTEX_CMP_REQUEUE_PI text 
Reported-by: Darren Hart <dvhart@linux.intel.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:45 +01:00
Michael Kerrisk 55a8bca383 futex.2: srcfix: remove obsolete FIXME 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:45 +01:00
Michael Kerrisk 1f043693de futex.2: tfix 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:45 +01:00
Michael Kerrisk f48516d113 futex.2: ERRORS: added EAGAIN case for FUTEX_WAIT_REQUEUE_PI 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:45 +01:00
Michael Kerrisk 63bea7dcbb futex.2: Describe 'timeout' argument of FUTEX_WAIT_REQUEUE_PI 2015-12-15 14:39:45 +01:00
Michael Kerrisk a4e6991290 futex.2: srcfix: FIXME 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:45 +01:00
Thomas Gleixner 6ff1b4c013 futex.2: Document FUTEX_WAIT_REQUEUE_PI 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:45 +01:00
Michael Kerrisk c6d8cf213c futex.2: srcfix 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:45 +01:00
Michael Kerrisk 936876a994 futex.2: wfix 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:45 +01:00
Michael Kerrisk de5a3bb47d futex.2: wfix 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:45 +01:00
Michael Kerrisk a696857697 futex.2: srcfix 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:45 +01:00
Michael Kerrisk 768d3c2355 futex.2: Use 'val2' as the term for 'timeout' cast to 'u32' 
This simplifies the text somewhat, so we don't need
to repeatedly describe how 'timeout' is cast 'u32'.

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:45 +01:00
Michael Kerrisk 99c0041df4 futex.2: ERRORS: add another EINVAL case (uaddr2) for FUTEX_CMP_REQUEUE_PI 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:45 +01:00
Michael Kerrisk f9250b1a1a futex.2: ERRORS: add EINVAL case for FUTEX_CMP_REQUEUE_PI 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:45 +01:00
Michael Kerrisk 025e137469 futex.2: ffix 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:45 +01:00
Michael Kerrisk 476debd7ea futex.2: ERRORS: place two similar EINVAL cases together 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:44 +01:00
Michael Kerrisk 662c0da854 futex.2: ERRORS: add EDEADLK case for FUTEX_CMP_REQUEUE_PI 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:44 +01:00
Michael Kerrisk dc2742a8aa futex.2: ERRORS: add EPERM case for FUTEX_CMP_REQUEUE_PI 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:44 +01:00
Michael Kerrisk 04331c3fd8 futex.2: wfix for EPERM error 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:44 +01:00
Michael Kerrisk 5eeca85632 futex.2: srcfix: add FIXME for "spurios wakeup" question from Rich Felker 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:44 +01:00
Michael Kerrisk 2043f2c133 futex.2: ERRORS: added EINVAL case for FUTEX_CMP_REQUEUE_PI 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:44 +01:00
Michael Kerrisk 670b34f8e8 futex.2: srcfix: FIXME 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:44 +01:00
Michael Kerrisk 794bb106f4 futex.2: ERRORS: add ENOSYS case for FUTEX_WAIT_REQUEUE_PI 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:44 +01:00
Michael Kerrisk 4945ff19bb futex.2: ERRORS: add ENOSYS case for FUTEX_CMP_REQUEUE_PI 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:44 +01:00
Michael Kerrisk a2ebebcdc7 futex.2: wfix for ENOSYS error 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:44 +01:00
Michael Kerrisk 8f2068bbe4 futex.2: ERRORS: add EAGAIN case for FUTEX_CMP_REQUEUE_PI (uaddr futex != val3) 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:44 +01:00
Michael Kerrisk aaec90325b futex.2: ERRORS: add EAGAIN case for FUTEX_CMP_REQUEUE_PI (uaddr2 owner exiting) 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:44 +01:00
Michael Kerrisk 8727670917 futex.2: tfix 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:44 +01:00
Michael Kerrisk ce5602fde5 futex.2: wfix 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:44 +01:00
Michael Kerrisk 360f773c2b futex.2: ERRORS: add ESRCH case for FUTEX_CMP_REQUEUE_PI 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:44 +01:00
Michael Kerrisk 2ed261994a futex.2: SEE ALSO: add pointer to Hart LWN.net article 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:44 +01:00
Michael Kerrisk f6af90e736 futex.2: ffix (ASCII art layout) 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:44 +01:00
Michael Kerrisk c8b921bd42 futex.2: tfix 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:44 +01:00
Michael Kerrisk c84cf68c3b futex.2: wfix 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:44 +01:00
Michael Kerrisk be37667386 futex.2: srcfix: FIXME 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:44 +01:00
Michael Kerrisk fc57e6bb5e futex.2: srcfix: FIXME 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:44 +01:00
Michael Kerrisk e34a8fb6c3 futex.2: ERRORS: Add ENOMEM case for FUTEX_CMP_REQUEUE_PI 
Reported-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:44 +01:00
Michael Kerrisk 9e54d26d3c futex.2: Add further details for FUTEX_CMP_REQUEUE_PI 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:44 +01:00
Darren Hart f812a08b1d futex.2: Describe FUTEX_CMP_REQUEUE_PI 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:44 +01:00
Michael Kerrisk 084744ef24 futex.2: Note arguments ignored by FUTEX_TRYLOCK_PI 
Reported-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:44 +01:00
Michael Kerrisk 11a194bff8 futex.2: wfix 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:44 +01:00
Michael Kerrisk 0b76182603 futex.2: srfix: FIXME 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:43 +01:00
Michael Kerrisk c0091dd3ff futex.2: srcfix: FIXME 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:43 +01:00
Michael Kerrisk badbf70cad futex.2: Replace instances of EWOULDBLOCK by EAGAIN 
On Linux, the two error numbers are the same. The kernel
code for futexes is somehwat inconsistent, using EAGAIN
in some places, and EWOULDBLOCK in others. Let's make the
manual page consistent at least.

This change requires reordering of one entry in ERRORS.

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:43 +01:00
Michael Kerrisk fa0388c309 futex.2: Rework FUTEXT_TRYLOCK_PI text a litte + add FIXMEs 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:43 +01:00
Michael Kerrisk 67833bec78 futex.2: Rework FUTEX_LOCK_PI text and add FIXMEs 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:43 +01:00
Michael Kerrisk b52e1cd4a8 futex.2: Further tweaks to PI introductory text 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:43 +01:00
Michael Kerrisk f5ad572fcf futex.2: ffix 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:43 +01:00
Michael Kerrisk 0483b6cce7 futex.2: Add more references to SEE ALSO 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:43 +01:00
Michael Kerrisk 79d918c7af futex.2: Rework Hart/Guniguntala text 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:43 +01:00
Michael Kerrisk 7c16fbff95 futex.2: Integrate text from Darren Hart on PI Mutexes 
From the 2009 Real-Time Linux Workshop paper
Requeue-PI: Making Glibc Condvars PI-Aware
Darren Hart, Dinakar Guniguntala
http://lwn.net/images/conf/rtlws11/papers/proc/p10.pdf

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:43 +01:00
Michael Kerrisk b4d4f5c537 futex.2: srcfix: Remove obsolete FIXME 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:43 +01:00
Michael Kerrisk bd90a5f9c3 futex.2: Add subsection for PI futexes 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:43 +01:00
Michael Kerrisk 9ce19cf1b7 futex.2: Fix discussion of FUTEX_LOCK_PI 'timeout' argument 
Reading futex_lock_pi(), it appears that the timeout is *not*
interpreted in the same way as for FUTEX_WAKE.

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:43 +01:00
Michael Kerrisk a8b5b324e3 futex.2: RETURN VALUE: add FUTEX_WAKE_OP 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:43 +01:00
Michael Kerrisk 22c15de938 futex.2: RETURN VALUE: add FUTEX_WAIT_REQUEUE_PI 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:43 +01:00
Michael Kerrisk dddd395a8d futex.2: RETURN VALUE: add FUTEX_CMP_REQUEUE_PI 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:43 +01:00
Michael Kerrisk 52bb928f26 futex.2: RETURN VALUE: add FUTEX_UNLOCK_PI 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:43 +01:00
Michael Kerrisk 5c716eef68 futex.2: RETURN VALUE: add FUTEX_TRYLOCK_PI 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:43 +01:00
Michael Kerrisk bf02a260f4 futex.2: RETURN VALUE: add FUTEX_LOCK_PI 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:43 +01:00
Michael Kerrisk b884566b97 futex.2: RETURN VALUE: add FUTEX_WAKE_BITSET 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:43 +01:00
Michael Kerrisk 7bcc535166 futex.2: RETURN VALUE: add FUTEX_WAIT_BITSET 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:43 +01:00
Michael Kerrisk 7446a8373c futex.2: RETURN VALUE: mention FUTEX_WAKE_BITSET under FUTEX_WAIT 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:43 +01:00
Michael Kerrisk 8f23887259 futex.2: Remove uneeded reference to ERRORS section 
(The need to read ERRORS is implied.)

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:43 +01:00
Michael Kerrisk dcad19c0c1 futex.2: RETURN VALUE: add placeholder for various operations 
There are still several operations whose return value
is not yet described.

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:43 +01:00
Michael Kerrisk 76f347bada futex.2: ERRORS: Add EPERM case for FUTEX_UNLOCK_PI 
Reported-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:43 +01:00
Michael Kerrisk f2424faec3 futex.2: ERRORS: Add ENOSYS case for FUTEX_UNLOCK_PI 
Reported-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:43 +01:00
Michael Kerrisk ce022f1841 futex.2: ERRORS: Add EINVAL case for FUTEX_UNLOCK_PI 
Reported-by: Thomas Gleixner <tglx@linutronix.de>

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:42 +01:00
Thomas Gleixner ecae2099c5 futex.2: Document FUTEX_UNLOCK_PI 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:42 +01:00
Michael Kerrisk 34f14794b5 futex.2: srcfix: FIXME 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:42 +01:00
Michael Kerrisk 12fdbe23b2 futex.2: Rearrange order FUTEX_UNLOCK_PI in list of operations 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:42 +01:00
Michael Kerrisk a9dcb4d1de futex.2: ERRORS: Add ENOSYS case for FUTEX_LOCK_PI and FUTEX_TRYLOCK_PI 
Reported-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:42 +01:00
Michael Kerrisk fedaeaf35c futex.2: srcfix: Add FIXME for the FUTEX_OWNER_DIED condition 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:42 +01:00
Michael Kerrisk d08ce5dd00 futex.2: srcfix: Add FIXME 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:42 +01:00
Michael Kerrisk 7a39e745a7 futex.2: ERRORS: Add EDEADLK case for FUTEX_LOCK_PI and FUTEX_TRYLOCK_PI 
Reported-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:42 +01:00
Michael Kerrisk 6f147f79bf futex.2: wfix 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:42 +01:00
Michael Kerrisk 61f8c1d19b futex.2: srcfix: add FIXMEs 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:42 +01:00
Michael Kerrisk 5662f56a3d futex.2: ERRORS: Add EAGAIN case for FUTEX_LOCK_PI and FUTEX_TRYLOCK_PI 
Reported-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:42 +01:00
Michael Kerrisk 0b0e49344a futex.2: ERRORS: Add ESRCH case for FUTEX_LOCK_PI and FUTEX_TRYLOCK_PI 
Reported-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:42 +01:00
Michael Kerrisk c7589177b7 futex.2: ERRORS: Add EPERM case for FUTEX_LOCK_PI and FUTEX_TRYLOCK_PI 
Reported-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:42 +01:00
Michael Kerrisk a218ef20dc futex.2: ERRORS: Add EINVAL case for FUTEX_LOCK_PI and FUTEX_TRYLOCK_PI 
Reported-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:42 +01:00
Michael Kerrisk 672595267c futex.2: srcfix: Add some FIXMEs for FUTEX_LOCK_PI 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:42 +01:00
Michael Kerrisk a449c6342a futex.2: ERRORS: Add ENOMEM for FUTEX_LOCK_PI and FUTEX_TRYLOCK_PI 
Reported-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:42 +01:00
Thomas Gleixner e0547e70ae futex.2: Document FUTEX_LOCK_PI 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:42 +01:00
Michael Kerrisk dcdfde2633 futex.2: srcfix 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:42 +01:00
Michael Kerrisk f2103b2686 futex.2: wfix 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:42 +01:00
Michael Kerrisk 43b9908905 futex.2: SEE ALSO: add Documentation/{pi-futex.txt,futex-requeue-pi.txt} 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:42 +01:00
Michael Kerrisk dd218aaa9d futex.2: srcfix: add FIXMEs 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:42 +01:00
Michael Kerrisk 9913033cf0 futex.2: SEE ALSO: add get_robust_list(2) 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:42 +01:00
Michael Kerrisk 09cb4ce716 futex.2: tfix 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:42 +01:00
Michael Kerrisk a7c2bf45b7 futex.2: Reorder operations list more or less chronologically 
Since there are various sets of related futex operations
that were added at the same time, ordering the descriptions
of operations chronologically makes some sense. In the
meantime, though, keep all of the "PI" operations together.

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:42 +01:00
Michael Kerrisk 63d3f91178 futex.2: tfix 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:42 +01:00
Michael Kerrisk e9d4496bf3 futex.2: Add discussion of FUTEX_WAIT_BITSET/FUTEX_WAKE_BITSET "multiplexing" 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:42 +01:00
Michael Kerrisk 98d769c098 futex.2: Enhance FUTEX_WAKE_BITSET text 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:41 +01:00
Thomas Gleixner 55cc422d78 futex.2: Document FUTEX_WAKE_BITSET 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:41 +01:00
Michael Kerrisk fd9e59d424 futex.2: Add description of FUTEX_WAIT_BITSET 'timeout' argument 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:41 +01:00
Thomas Gleixner 79c9b4366e futex.2: Document FUTEX_WAIT_BITSET 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:41 +01:00
Michael Kerrisk 5447735dd2 futex.2: Consolidate EINVAL FUTEX_LOCK_PI errors 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:41 +01:00
Michael Kerrisk 52dee70ef0 futex.2: wfix 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:41 +01:00
Michael Kerrisk 180f97b797 futex.2: Reword invalid timeout EINVAL case more generally 
Several operations can produce this error, so reword
the text more generally.

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:41 +01:00
Michael Kerrisk 6b060884c5 futex.2: srcfix: added FIXMES 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:41 +01:00
Michael Kerrisk 0582b19df0 futex.2: wfix 
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
 2015-12-15 14:39:41 +01:00