linux/kernel/sched
Steven Rostedt (VMware) 364f566537 sched/rt: Up the root domain ref count when passing it around via IPIs
When issuing an IPI RT push, where an IPI is sent to each CPU that has more
than one RT task scheduled on it, it references the root domain's rto_mask,
that contains all the CPUs within the root domain that has more than one RT
task in the runable state. The problem is, after the IPIs are initiated, the
rq->lock is released. This means that the root domain that is associated to
the run queue could be freed while the IPIs are going around.

Add a sched_get_rd() and a sched_put_rd() that will increment and decrement
the root domain's ref count respectively. This way when initiating the IPIs,
the scheduler will up the root domain's ref count before releasing the
rq->lock, ensuring that the root domain does not go away until the IPI round
is complete.

Reported-by: Pavan Kondeti <pkondeti@codeaurora.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: 4bdced5c9a ("sched/rt: Simplify the IPI based RT balancing logic")
Link: http://lkml.kernel.org/r/CAEU1=PkiHO35Dzna8EQqNSKW1fr1y1zRQ5y66X117MG06sQtNA@mail.gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-02-06 10:20:33 +01:00
..
autogroup.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
autogroup.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
clock.c sched/clock, sched/cputime: Use lockdep to assert IRQs are disabled/enabled 2017-11-08 11:13:53 +01:00
completion.c locking/lockdep: Remove cross-release leftovers 2018-01-08 17:30:45 +01:00
core.c sched/core: Optimize ttwu_stat() 2018-02-06 10:20:31 +01:00
cpuacct.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
cpudeadline.c sched/deadline: Change return value of cpudl_find() 2017-08-10 12:18:17 +02:00
cpudeadline.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
cpufreq_schedutil.c sched/cpufreq: Always consider all CPUs when deciding next freq 2018-01-10 12:53:34 +01:00
cpufreq.c
cpupri.c sched/cpupri: Don't re-initialize 'struct cpupri' 2017-08-10 12:18:14 +02:00
cpupri.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
cputime.c Merge branch 'for-4.15' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup 2017-11-15 14:29:44 -08:00
deadline.c sched/deadline: Make bandwidth enforcement scale-invariant 2018-01-10 12:53:35 +01:00
debug.c sched/fair: Propagate an effective runnable_load_avg 2017-09-29 19:35:15 +02:00
fair.c sched/core: Optimize update_stats_*() 2018-02-06 10:20:32 +01:00
features.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
idle_task.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
idle.c sched/idle: Micro-optimize the idle loop 2017-10-26 08:31:29 +02:00
isolation.c sched/isolation: Add basic isolcpus flags 2017-10-27 09:55:31 +02:00
loadavg.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
Makefile Merge branch 'linus' into sched/core, to pick up fixes 2017-11-08 10:17:15 +01:00
membarrier.c membarrier: Provide core serializing command, *_SYNC_CORE 2018-02-05 21:35:03 +01:00
rt.c sched/rt: Up the root domain ref count when passing it around via IPIs 2018-02-06 10:20:33 +01:00
sched-pelt.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
sched.h sched/rt: Up the root domain ref count when passing it around via IPIs 2018-02-06 10:20:33 +01:00
stats.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
stats.h sched/core: Optimize update_stats_*() 2018-02-06 10:20:32 +01:00
stop_task.c Merge branch 'for-4.15' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup 2017-11-15 14:29:44 -08:00
swait.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
topology.c sched/rt: Up the root domain ref count when passing it around via IPIs 2018-02-06 10:20:33 +01:00
wait_bit.c Pass mode to wait_on_atomic_t() action funcs and provide default actions 2017-11-13 15:38:16 +00:00
wait.c sched/wait: Fix add_wait_queue() behavioral change 2017-12-06 19:30:34 +01:00