linux-stable/kernel/rcu
Paul E. McKenney a94844b22a rcu: Optionally run grace-period kthreads at real-time priority
Recent testing has shown that under heavy load, running RCU's grace-period
kthreads at real-time priority can improve performance (according to 0day
test robot) and reduce the incidence of RCU CPU stall warnings.  However,
most systems do just fine with the default non-realtime priorities for
these kthreads, and it does not make sense to expose the entire user
base to any risk stemming from this change, given that this change is
of use only to a few users running extremely heavy workloads.

Therefore, this commit allows users to specify realtime priorities
for the grace-period kthreads, but leaves them running SCHED_OTHER
by default.  The realtime priority may be specified at build time
via the RCU_KTHREAD_PRIO Kconfig parameter, or at boot time via the
rcutree.kthread_prio parameter.  Either way, 0 says to continue the
default SCHED_OTHER behavior and values from 1-99 specify that priority
of SCHED_FIFO behavior.  Note that a value of 0 is not permitted when
the RCU_BOOST Kconfig parameter is specified.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2015-01-15 23:25:04 -08:00
..
Makefile rcu: Remove redundant TREE_PREEMPT_RCU config option 2014-10-29 10:20:05 -07:00
rcu.h rcutorture: Add early boot self tests 2014-11-03 19:26:37 -08:00
rcutorture.c rcutorture: Fix rcu_torture_cbflood() memory leak 2014-11-03 19:26:41 -08:00
srcu.c rcu: Eliminate read-modify-write ACCESS_ONCE() calls 2014-07-09 09:14:49 -07:00
tiny.c Merge branches 'torture.2014.11.03a', 'cpu.2014.11.03a', 'doc.2014.11.13a', 'fixes.2014.11.13a', 'signal.2014.10.29a' and 'rt.2014.10.29a' into HEAD 2014-11-13 10:39:04 -08:00
tiny_plugin.h rcu: Protect uses of ->jiffies_stall with ACCESS_ONCE() 2014-04-29 08:44:41 -07:00
tree.c rcu: Optionally run grace-period kthreads at real-time priority 2015-01-15 23:25:04 -08:00
tree.h rcu: Handle gpnum/completed wrap while dyntick idle 2015-01-06 11:05:28 -08:00
tree_plugin.h rcu: Optionally run grace-period kthreads at real-time priority 2015-01-15 23:25:04 -08:00
tree_trace.c rcu: Stop tracking FSF's postal address 2014-02-17 15:01:37 -08:00
update.c Merge branches 'torture.2014.11.03a', 'cpu.2014.11.03a', 'doc.2014.11.13a', 'fixes.2014.11.13a', 'signal.2014.10.29a' and 'rt.2014.10.29a' into HEAD 2014-11-13 10:39:04 -08:00