This adds new functions for futex operations, starting with wait,
abstimed_wait, reltimed_wait, wake. They add documentation and error
checking according to the current draft of the Linux kernel futex manpage.
Waiting with absolute or relative timeouts is split into separate functions.
This allows for removing a few cases of code duplication in pthreads code,
which uses absolute timeouts; also, it allows us to put platform-specific
code to go from an absolute to a relative timeout into the platform-specific
futex abstractions..
Futex operations that can be canceled are also split out into separate
functions suffixed by "_cancelable".
There are separate versions for both Linux and NaCl; while they currently
differ only slightly, my expectation is that the separate versions of
lowlevellock-futex.h will eventually be merged into futex-internal.h
when we get to move the lll_ functions over to the new futex API.
This patch combines BUSY_WAIT_NOP and atomic_delay into a new
atomic_spin_nop function and adjusts all clients. The new function is
put into atomic.h because what is best done in a spin loop is
architecture-specific, and atomics must be used for spinning. The
function name is meant to tell users that this has no effect on
synchronization semantics but is a performance aid for spinning.
On 21/05/15 05:29, Siddhesh Poyarekar wrote:
> On Wed, May 20, 2015 at 06:55:02PM +0100, Szabolcs Nagy wrote:
>> i guess it's ok for consistency if i fix struct stat64
>> too to use __USE_XOPEN2K8.
>>
>> i will run some tests and come back with a patch
>
> I also think it would be appropriate to change this code in other
> architectures (microblaze and nacl IIRC) to make all of them
> consistent. It is a mechanical enough change IMO that all arch
> maintainer acks is not necessary.
>
here is the patch with consistent __USE_XOPEN2K8
ok to commit?
2015-05-21 Szabolcs Nagy <szabolcs.nagy@arm.com>
[BZ #18234]
* conform/data/sys/stat.h-data (struct stat): Add tests for st_atim,
st_mtim and st_ctim members.
* sysdeps/nacl/bits/stat.h (struct stat, struct stat64): Make
st_atim, st_ctim, st_mtim visible under __USE_XOPEN2K8 only.
* sysdeps/unix/sysv/linux/generic/bits/stat.h (struct stat,):
(struct stat64): Likewise.
* sysdeps/unix/sysv/linux/ia64/bits/stat.h (struct stat,):
(struct stat64): Likewise.
* sysdeps/unix/sysv/linux/microblaze/bits/stat.h (struct stat,):
(struct stat64): Likewise.
Roland McGrath
Torvald Riegel
Szabolcs Nagy