linux/include
Richard Cochran 1791f88143 posix clocks: Replace mutex with reader/writer semaphore
A dynamic posix clock is protected from asynchronous removal by a mutex.
However, using a mutex has the unwanted effect that a long running clock
operation in one process will unnecessarily block other processes.

For example, one process might call read() to get an external time stamp
coming in at one pulse per second. A second process calling clock_gettime
would have to wait for almost a whole second.

This patch fixes the issue by using a reader/writer semaphore instead of
a mutex.

Signed-off-by: Richard Cochran <richard.cochran@omicron.at>
Cc: John Stultz <john.stultz@linaro.org>
Link: http://lkml.kernel.org/r/%3C20110330132421.GA31771%40riccoc20.at.omicron.at%3E
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-04-18 10:39:38 +02:00
..
acpi Fix common misspellings 2011-03-31 11:26:23 -03:00
asm-generic Merge branch 'for-linus2' of git://git.profusion.mobi/users/lucas/linux-2.6 2011-04-07 11:14:49 -07:00
crypto
drm Merge branch 'for-linus2' of git://git.profusion.mobi/users/lucas/linux-2.6 2011-04-07 11:14:49 -07:00
keys libceph: Create a new key type "ceph". 2011-03-29 12:11:24 -07:00
linux posix clocks: Replace mutex with reader/writer semaphore 2011-04-18 10:39:38 +02:00
math-emu
media Fix common misspellings 2011-03-31 11:26:23 -03:00
mtd
net net/9p: nwname should be an unsigned int 2011-04-15 15:26:15 -05:00
pcmcia pcmcia: re-enable Zoomed Video support 2011-02-20 12:47:34 +01:00
rdma RDMA: Update workqueue usage 2011-01-16 21:16:31 -08:00
rxrpc Fix common misspellings 2011-03-31 11:26:23 -03:00
scsi Fix common misspellings 2011-03-31 11:26:23 -03:00
sound Merge branch 'for-linus2' of git://git.profusion.mobi/users/lucas/linux-2.6 2011-04-07 11:14:49 -07:00
staging [media] Altera FPGA firmware download module 2011-03-21 20:32:16 -03:00
target Fix common misspellings 2011-03-31 11:26:23 -03:00
trace block: make unplug timer trace event correspond to the schedule() unplug 2011-04-16 13:51:05 +02:00
video Fix common misspellings 2011-03-31 11:26:23 -03:00
xen Fix common misspellings 2011-03-31 11:26:23 -03:00
Kbuild