[PATCH] posix timers: RCU optimization for clock_gettime()

Use RCU to avoid the need to acquire tasklist_lock in the single-threaded
case of clock_gettime().  It still acquires tasklist_lock when for a
(potentially multithreaded) process.  This change allows realtime
applications to frequently monitor CPU consumption of individual tasks, as
requested (and now deployed) by some off-list users.

This has been in Ingo Molnar's -rt patchset since late 2005 with no
problems reported, and tests successfully on 2.6.20-rc6, so I believe that
it is long-since ready for mainline adoption.

[[email protected]: fix exit()/posix_cpu_clock_get() race spotted by Oleg]
Signed-off-by: Paul E. McKenney <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: john stultz <[email protected]>
Cc: Roman Zippel <[email protected]>
Cc: Oleg Nesterov <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

0 files changed, 0 insertions, 0 deletions