linux/kernel/sched
Rik van Riel 25b3e5a334 sched/numa: Fix math underflow in task_tick_numa()
The NUMA balancing code implements delays in scanning by
advancing curr->node_stamp beyond curr->se.sum_exec_runtime.

With unsigned math, that creates an underflow, which results
in task_numa_work being queued all the time, even when we
don't want to.

Avoiding the math underflow makes it possible to reduce CPU
overhead in the NUMA balancing code.

Reported-and-tested-by: Jan Stancek <jstancek@redhat.com>
Signed-off-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: mgorman@suse.de
Link: http://lkml.kernel.org/r/1446756983-28173-2-git-send-email-riel@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-11-09 16:13:27 +01:00
..
auto_group.c sched, timer: Convert usages of ACCESS_ONCE() in the scheduler to READ_ONCE()/WRITE_ONCE() 2015-05-08 12:11:32 +02:00
auto_group.h sched, timer: Convert usages of ACCESS_ONCE() in the scheduler to READ_ONCE()/WRITE_ONCE() 2015-05-08 12:11:32 +02:00
clock.c kernel/sched/clock.c: add another clock for use with the soft lockup watchdog 2015-02-12 18:54:13 -08:00
completion.c sched/completion: Serialize completion_done() with complete() 2015-02-18 14:27:40 +01:00
core.c Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2015-11-03 18:03:50 -08:00
cpuacct.c cgroup: rename cgroup_subsys->base_cftypes to ->legacy_cftypes 2014-07-15 11:05:09 -04:00
cpuacct.h sched/cpuacct: Initialize root cpuacct earlier 2013-04-10 13:54:20 +02:00
cpudeadline.c sched/deadline: Unify dl_time_before() usage 2015-09-23 09:51:25 +02:00
cpudeadline.h sched/deadline: Unify dl_time_before() usage 2015-09-23 09:51:25 +02:00
cpupri.c Merge commit '3cf2f34' into sched/core, to fix build error 2014-06-12 13:46:37 +02:00
cpupri.h sched/cpupri: Remove unnecessary definitions in cpupri.h 2014-11-16 10:58:59 +01:00
cputime.c sched/cputime: Guarantee stime + utime == rtime 2015-08-03 12:21:21 +02:00
deadline.c sched/core: Add missing lockdep_unpin() annotations 2015-10-23 12:02:10 +02:00
debug.c sched/fair: Provide runnable_load_avg back to cfs_rq 2015-08-03 12:24:31 +02:00
fair.c sched/numa: Fix math underflow in task_tick_numa() 2015-11-09 16:13:27 +01:00
features.h sched/fair: Convert arch_scale_cpu_capacity() from weak function to #define 2015-09-13 09:52:55 +02:00
idle_task.c sched: Make sched_class::set_cpus_allowed() unconditional 2015-08-12 12:06:09 +02:00
idle.c sched, tracing: Stop/start critical timings around the idle=poll idle loop 2015-10-12 09:45:25 +02:00
loadavg.c sched: Move the loadavg code to a more obvious location 2015-05-08 12:04:12 +02:00
Makefile sched: Move the loadavg code to a more obvious location 2015-05-08 12:04:12 +02:00
rt.c sched/rt: Make (do_)balance_runtime() return void 2015-09-23 09:51:26 +02:00
sched.h sched/core: Remove a parameter in the migrate_task_rq() function 2015-10-06 17:08:23 +02:00
stats.c sched: use %*pb[l] to print bitmaps including cpumasks and nodemasks 2015-02-13 21:21:37 -08:00
stats.h sched/stat: Simplify the sched_info accounting dependency 2015-07-04 10:04:30 +02:00
stop_task.c sched: Make sched_class::set_cpus_allowed() unconditional 2015-08-12 12:06:09 +02:00
wait.c userfaultfd: revert "userfaultfd: waitqueue: add nr wake parameter to __wake_up_locked_key" 2015-09-22 15:09:53 -07:00