Files
linux/kernel
Soumya PN 6112a300c9 ftrace: Don't disable irqs when taking the tasklist_lock read_lock
In ftrace.c inside the function alloc_retstack_tasklist() (which will be
invoked when function_graph tracing is on) the tasklist_lock is being
held as reader while iterating through a list of threads. Here the lock
is being held as reader with irqs disabled. The tasklist_lock is never
write_locked in interrupt context so it is safe to not disable interrupts
for the duration of read_lock in this block which, can be significant,
given the block of code iterates through all threads. Hence changing the
code to call read_lock() and read_unlock() instead of read_lock_irqsave()
and read_unlock_irqrestore().

A similar change was made in commits: 8063e41d2f ("tracing: Change
syscall_*regfunc() to check PF_KTHREAD and use for_each_process_thread()")'
and 3472eaa1f1 ("sched: normalize_rt_tasks(): Don't use _irqsave for
tasklist_lock, use task_rq_lock()")'

Link: http://lkml.kernel.org/r/1463500874-77480-1-git-send-email-soumya.p.n@hpe.com

Signed-off-by: Soumya PN <soumya.p.n@hpe.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-05-20 13:19:37 -04:00
..
2015-12-04 22:46:25 +01:00
2016-03-22 15:36:02 -07:00
2015-04-11 22:27:55 -04:00
2015-11-19 17:51:48 +01:00
2016-01-22 18:04:28 -05:00
2016-02-08 11:25:39 -05:00
2015-12-14 14:54:37 -05:00
2016-03-12 20:57:38 +01:00
2015-04-12 21:03:31 +02:00
2016-03-22 15:36:02 -07:00
2015-11-23 09:44:58 +01:00
2016-03-22 15:36:02 -07:00
2016-03-22 15:36:02 -07:00
2016-03-22 15:36:02 -07:00
2016-02-16 13:04:58 -05:00
2016-01-22 18:04:28 -05:00
2016-03-01 20:36:56 +01:00