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  1. 23 5月, 2011 1 次提交
  3. 31 3月, 2011 1 次提交
  5. 22 2月, 2011 1 次提交
  7. 02 2月, 2011 22 次提交
  9. 21 10月, 2010 1 次提交
  11. 23 7月, 2010 1 次提交
  13. 28 5月, 2010 1 次提交
  15. 05 2月, 2010 1 次提交
  17. 22 8月, 2009 1 次提交
    • J
      time: Introduce CLOCK_REALTIME_COARSE · da15cfda
      由 john stultz 提交于 
      After talking with some application writers who want very fast, but not
fine-grained timestamps, I decided to try to implement new clock_ids
to clock_gettime(): CLOCK_REALTIME_COARSE and CLOCK_MONOTONIC_COARSE
which returns the time at the last tick. This is very fast as we don't
have to access any hardware (which can be very painful if you're using
something like the acpi_pm clocksource), and we can even use the vdso
clock_gettime() method to avoid the syscall. The only trade off is you
only get low-res tick grained time resolution.

This isn't a new idea, I know Ingo has a patch in the -rt tree that made
the vsyscall gettimeofday() return coarse grained time when the
vsyscall64 sysctrl was set to 2. However this affects all applications
on a system.

With this method, applications can choose the proper speed/granularity
trade-off for themselves.
Signed-off-by: NJohn Stultz <johnstul@us.ibm.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: nikolag@ca.ibm.com
Cc: Darren Hart <dvhltc@us.ibm.com>
Cc: arjan@infradead.org
Cc: jonathan@jonmasters.org
LKML-Reference: <1250734414.6897.5.camel@localhost.localdomain>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
      da15cfda
  19. 04 8月, 2009 1 次提交
  21. 14 1月, 2009 1 次提交
  23. 21 12月, 2008 1 次提交
  25. 13 12月, 2008 2 次提交
    • O
      posix-timers: check ->it_signal instead of ->it_pid to validate the timer · 89992102
      由 Oleg Nesterov 提交于 
      Impact: clean up, speed up

->it_pid (was ->it_process) has also a special meaning: if it is NULL,
the timer is under deletion or it wasn't initialized yet. We can check
->it_signal != NULL instead, this way we can

	- simplify sys_timer_create() a bit

	- remove yet another check from lock_timer()

	- move put_pid(->it_pid) into release_posix_timer() which
	  runs outside of ->it_lock
Signed-off-by: NOleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
      89992102
    • O
      posix-timers: use "struct pid*" instead of "struct task_struct*" · 27af4245
      由 Oleg Nesterov 提交于 
      Impact: restructure, clean up code

k_itimer holds the ref to the ->it_process until sys_timer_delete(). This
allows to pin up to RLIMIT_SIGPENDING dead task_struct's. Change the code
to use "struct pid *" instead.

The patch doesn't kill ->it_process, it places ->it_pid into the union.
->it_process is still used by do_cpu_nanosleep() as before. It would be
trivial to change the nanosleep code as well, but since it uses it_process
in a special way I think it is better to keep this field for grep.

The patch bloats the kernel by 104 bytes and it also adds the new pointer,
->it_signal, to k_itimer. It is used by lock_timer() to verify that the
found timer was not created by another process. It is not clear why do we
use the global database (and thus the global idr_lock) for posix timers.
We still need the signal_struct->posix_timers which contains all useable
timers, perhaps it is better to use some form of per-process array
instead.
Signed-off-by: NOleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
      27af4245
  27. 03 10月, 2008 1 次提交
  29. 24 9月, 2008 4 次提交