remarkable-linux/kernel
Paul E. McKenney 5cc900cf55 rcu: Improve boost selection when moving tasks to root rcu_node
The rcu_preempt_offline_tasks() moves all tasks queued on a given leaf
rcu_node structure to the root rcu_node, which is done when the last CPU
corresponding the the leaf rcu_node structure goes offline.  Now that
RCU-preempt's synchronize_rcu_expedited() implementation blocks CPU-hotplug
operations during the initialization of each rcu_node structure's
->boost_tasks pointer, rcu_preempt_offline_tasks() can do a better job
of setting the root rcu_node's ->boost_tasks pointer.

The key point is that rcu_preempt_offline_tasks() runs as part of the
CPU-hotplug process, so that a concurrent synchronize_rcu_expedited()
is guaranteed to either have not started on the one hand (in which case
there is no boosting on behalf of the expedited grace period) or to be
completely initialized on the other (in which case, in the absence of
other priority boosting, all ->boost_tasks pointers will be initialized).
Therefore, if rcu_preempt_offline_tasks() finds that the ->boost_tasks
pointer is equal to the ->exp_tasks pointer, it can be sure that it is
correctly placed.

In the case where there was boosting ongoing at the time that the
synchronize_rcu_expedited() function started, different nodes might start
boosting the tasks blocking the expedited grace period at different times.
In this mixed case, the root node will either be boosting tasks for
the expedited grace period already, or it will start as soon as it gets
done boosting for the normal grace period -- but in this latter case,
the root node's tasks needed to be boosted in any case.

This commit therefore adds a check of the ->boost_tasks pointer against
the ->exp_tasks pointer to the list that prevents updating ->boost_tasks.

Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2012-09-23 07:42:50 -07:00
..
debug kernel/debug: Make use of KGDB_REASON_NMI 2012-07-31 08:16:43 -05:00
events perf/trace: Add ability to set a target task for events 2012-07-31 17:02:05 +02:00
gcov gcov: disable CONSTRUCTORS for UML 2011-07-26 16:49:45 -07:00
irq Merge branch 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2012-08-03 10:56:44 -07:00
power Revert "NMI watchdog: fix for lockup detector breakage on resume" 2012-08-08 20:49:45 +02:00
sched Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2012-08-20 10:35:05 -07:00
time time: Move ktime_t overflow checking into timespec_valid_strict 2012-09-01 10:24:48 -07:00
trace tracing/syscalls: Fix perf syscall tracing when syscall_nr == -1 2012-08-17 15:19:46 -04:00
.gitignore
acct.c Merge branch 'for-linus2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2012-01-08 12:19:57 -08:00
async.c [SCSI] async: make async_synchronize_full() flush all work regardless of domain 2012-07-20 09:07:37 +01:00
audit.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2012-08-01 10:26:23 -07:00
audit.h audit: remove AUDIT_SETUP_CONTEXT as it isn't used 2012-01-17 16:16:57 -05:00
audit_tree.c audit: clean up refcounting in audit-tree 2012-08-15 12:55:22 +02:00
audit_watch.c get rid of kern_path_parent() 2012-07-14 16:35:02 +04:00
auditfilter.c audit: allow interfield comparison in audit rules 2012-01-17 16:17:01 -05:00
auditsc.c seccomp: remove duplicated failure logging 2012-04-14 11:13:20 +10:00
backtracetest.c
bounds.c
capability.c userns: Teach inode_capable to understand inodes whose uids map to other namespaces. 2012-05-15 14:59:24 -07:00
cgroup.c Merge branch 'for-3.6' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup 2012-07-24 17:47:44 -07:00
cgroup_freezer.c cgroup: convert all non-memcg controllers to the new cftype interface 2012-04-01 12:09:55 -07:00
compat.c new helper: sigsuspend() 2012-05-21 23:52:30 -04:00
configs.c kernel/configs.c: include MODULE_*() when CONFIG_IKCONFIG_PROC=n 2011-07-25 20:57:15 -07:00
cpu.c mm/hotplug: correctly setup fallback zonelists when creating new pgdat 2012-07-31 18:42:44 -07:00
cpu_pm.c kernel/cpu_pm.c: fix various typos 2012-05-31 17:49:27 -07:00
cpuset.c cpusets: Remove/update outdated comments 2012-07-24 13:53:28 +02:00
crash_dump.c Merge branch 'modsplit-Oct31_2011' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux 2011-11-06 19:44:47 -08:00
cred.c keys: kill task_struct->replacement_session_keyring 2012-05-23 22:11:41 -04:00
delayacct.c KVM: Steal time implementation 2011-07-14 12:59:14 +03:00
dma.c Remove all #inclusions of asm/system.h 2012-03-28 18:30:03 +01:00
elfcore.c
exec_domain.c
exit.c posix_types.h: Cleanup stale __NFDBITS and related definitions 2012-07-26 13:36:43 -07:00
extable.c extable: Skip sorting if sorted at build time. 2012-04-19 15:06:55 -07:00
fork.c uprobes: Fix mmap_region()'s mm->mm_rb corruption if uprobe_mmap() fails 2012-08-21 11:48:12 +02:00
freezer.c PM / Freezer: Remove references to TIF_FREEZE in comments 2012-03-04 23:08:54 +01:00
futex.c futex: Forbid uaddr == uaddr2 in futex_wait_requeue_pi() 2012-07-24 16:02:57 +02:00
futex_compat.c futex: Mark get_robust_list as deprecated 2012-03-29 11:37:17 +02:00
groups.c userns: Convert in_group_p and in_egroup_p to use kgid_t 2012-05-03 03:29:33 -07:00
hrtimer.c hrtimer: Update hrtimer base offsets each hrtimer_interrupt 2012-07-11 23:34:39 +02:00
hung_task.c hung task debugging: Inject NMI when hung and going to panic 2012-04-25 12:39:25 +02:00
irq_work.c irq_work: fix compile failure on tile from missing include 2012-04-13 13:15:16 -04:00
itimer.c itimer: Use printk_once instead of WARN_ONCE 2012-04-10 11:00:30 +02:00
jump_label.c static keys: Inline the static_key_enabled() function 2012-02-28 20:01:08 +01:00
kallsyms.c vsprintf: fix %ps on non symbols when using kallsyms 2012-05-29 16:22:32 -07:00
kcmp.c syscalls, x86: add __NR_kcmp syscall 2012-05-31 17:49:32 -07:00
Kconfig.freezer
Kconfig.hz
Kconfig.locks locking/kconfig: Simplify INLINE_SPIN_UNLOCK usage 2012-03-23 13:18:57 +01:00
Kconfig.preempt locking/kconfig: Simplify INLINE_SPIN_UNLOCK usage 2012-03-23 13:18:57 +01:00
kexec.c kdump: append newline to the last lien of vmcoreinfo note 2012-07-30 17:25:20 -07:00
kfifo.c [media] kernel:kfifo: export __kfifo_max_r symbol 2012-04-11 18:24:37 -03:00
kmod.c kmod: avoid deadlock from recursive kmod call 2012-07-30 17:25:20 -07:00
kprobes.c kprobes: return proper error code from register_kprobe() 2012-03-05 15:49:42 -08:00
ksysfs.c kernel: ksysfs.c is implicitly using stat.h 2011-10-31 09:20:13 -04:00
kthread.c kthread_worker: reimplement flush_kthread_work() to allow freeing the work item being executed 2012-07-22 10:15:28 -07:00
latencytop.c kernel: Map most files to use export.h instead of module.h 2011-10-31 09:20:12 -04:00
lglock.c brlocks/lglocks: turn into functions 2012-05-29 23:28:41 -04:00
lockdep.c lockdep: Add CPU-idle/offline warning to lockdep-RCU splat 2012-02-21 09:06:06 -08:00
lockdep_internals.h
lockdep_proc.c kernel: Map most files to use export.h instead of module.h 2011-10-31 09:20:12 -04:00
lockdep_states.h
Makefile Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2012-06-01 10:34:35 -07:00
module.c Guard check in module loader against integer overflow 2012-05-23 22:28:53 +09:30
mutex-debug.c kernel: Map most files to use export.h instead of module.h 2011-10-31 09:20:12 -04:00
mutex-debug.h
mutex.c sched/rt: Use schedule_preempt_disabled() 2012-03-01 10:28:03 +01:00
mutex.h
notifier.c kernel: Map most files to use export.h instead of module.h 2011-10-31 09:20:12 -04:00
nsproxy.c kernel: Map most files to use export.h instead of module.h 2011-10-31 09:20:12 -04:00
padata.c padata: Fix cpu hotplug 2012-03-29 19:52:46 +08:00
panic.c panic: fix a possible deadlock in panic() 2012-07-30 17:25:13 -07:00
params.c params: replace printk(KERN_<LVL>...) with pr_<lvl>(...) 2012-05-04 17:28:18 -07:00
pid.c mm: add a low limit to alloc_large_system_hash 2012-05-24 00:28:21 -04:00
pid_namespace.c pidns: guarantee that the pidns init will be the last pidns process reaped 2012-06-20 14:39:36 -07:00
posix-cpu-timers.c [S390] cputime: add sparse checking and cleanup 2011-12-15 14:56:19 +01:00
posix-timers.c kernel: Map most files to use export.h instead of module.h 2011-10-31 09:20:12 -04:00
printk.c printk: Fix calculation of length used to discard records 2012-08-12 21:25:50 +03:00
profile.c kernel: Map most files to use export.h instead of module.h 2011-10-31 09:20:12 -04:00
ptrace.c userns: Convert ptrace, kill, set_priority permission checks to work with kuids and kgids 2012-05-03 03:28:51 -07:00
range.c range: fix bogus misuse of module.h to get printk() 2011-10-31 09:20:11 -04:00
rcu.h rcu: Allow nesting of rcu_idle_enter() and rcu_idle_exit() 2012-02-21 09:06:12 -08:00
rcupdate.c rcu: Add PROVE_RCU_DELAY to provoke difficult races 2012-09-23 07:42:49 -07:00
rcutiny.c rcu: Permit RCU_NONIDLE() to be used from interrupt context 2012-09-23 07:42:49 -07:00
rcutiny_plugin.h rcu: Fix code-style issues involving "else" 2012-07-06 06:01:48 -07:00
rcutorture.c rcu: Fix broken strings in RCU's source code. 2012-07-06 06:01:49 -07:00
rcutree.c rcu: Fix day-one dyntick-idle stall-warning bug 2012-09-23 07:31:52 -07:00
rcutree.h Merge branches 'bigrtm.2012.07.04a', 'doctorture.2012.07.02a', 'fixes.2012.07.06a' and 'fnh.2012.07.02a' into HEAD 2012-07-06 05:59:30 -07:00
rcutree_plugin.h rcu: Improve boost selection when moving tasks to root rcu_node 2012-09-23 07:42:50 -07:00
rcutree_trace.c rcu: Fix broken strings in RCU's source code. 2012-07-06 06:01:49 -07:00
relay.c splice: fix racy pipe->buffers uses 2012-06-13 21:16:42 +02:00
res_counter.c rescounters: add res_counter_uncharge_until() 2012-05-29 16:22:27 -07:00
resource.c resource: make sure requested range is included in the root range 2012-07-30 17:25:21 -07:00
rtmutex-debug.c lockdep, rtmutex, bug: Show taint flags on error 2011-12-06 08:16:49 +01:00
rtmutex-debug.h
rtmutex-tester.c rtmutex-tester: convert sysdev_class to a regular subsystem 2011-12-14 14:54:22 -08:00
rtmutex.c Revert "rcu: Permit rt_mutex_unlock() with irqs disabled" 2011-12-11 10:33:18 -08:00
rtmutex.h
rtmutex_common.h
rwsem.c Remove all #inclusions of asm/system.h 2012-03-28 18:30:03 +01:00
seccomp.c seccomp: fix build warnings when there is no CONFIG_SECCOMP_FILTER 2012-04-18 12:24:52 +10:00
semaphore.c semaphore: fix improper comment reference to mutex 2012-04-05 17:15:55 -07:00
signal.c signal: make sure we don't get stopped with pending task_work 2012-07-22 23:57:54 +04:00
smp.c smp: Remove ipi_call_lock[_irq]()/ipi_call_unlock[_irq]() 2012-06-05 17:27:14 +02:00
smpboot.c smpboot, idle: Fix comment mismatch over idle_threads_init() 2012-05-24 22:58:08 +02:00
smpboot.h smpboot: Remove leftover declaration 2012-06-11 15:07:52 +02:00
softirq.c mm: allow PF_MEMALLOC from softirq context 2012-07-31 18:42:45 -07:00
spinlock.c locking/kconfig: Simplify INLINE_SPIN_UNLOCK usage 2012-03-23 13:18:57 +01:00
srcu.c rcu: Implement per-domain single-threaded call_srcu() state machine 2012-04-30 10:48:25 -07:00
stacktrace.c kernel: Map most files to use export.h instead of module.h 2011-10-31 09:20:12 -04:00
stop_machine.c Merge branch 'modsplit-Oct31_2011' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux 2011-11-06 19:44:47 -08:00
sys.c kernel/sys.c: avoid argv_free(NULL) 2012-07-30 17:25:13 -07:00
sys_ni.c syscalls, x86: add __NR_kcmp syscall 2012-05-31 17:49:32 -07:00
sysctl.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2012-08-01 10:26:23 -07:00
sysctl_binary.c mm: prepare for removal of obsolete /proc/sys/vm/nr_pdflush_threads 2012-07-31 18:42:40 -07:00
task_work.c task_work: add a scheduling point in task_work_run() 2012-08-21 09:11:44 -07:00
taskstats.c taskstats: check nla_reserve() return 2012-07-30 17:25:21 -07:00
test_kprobes.c
time.c time: Remove bogus comments 2012-03-15 18:17:55 -07:00
timeconst.pl
timer.c alpha: take a bunch of syscalls into osf_sys.c 2012-08-19 08:41:19 -07:00
tracepoint.c static keys: Introduce 'struct static_key', static_key_true()/false() and static_key_slow_[inc|dec]() 2012-02-24 10:05:59 +01:00
tsacct.c [S390] cputime: add sparse checking and cleanup 2011-12-15 14:56:19 +01:00
uid16.c userns: Convert setting and getting uid and gid system calls to use kuid and kgid 2012-05-03 03:28:41 -07:00
up.c kernel: Map most files to use export.h instead of module.h 2011-10-31 09:20:12 -04:00
user-return-notifier.c kernel: Map most files to use export.h instead of module.h 2011-10-31 09:20:12 -04:00
user.c userns: Silence silly gcc warning. 2012-05-19 15:44:40 -06:00
user_namespace.c userns: Store uid and gid values in struct cred with kuid_t and kgid_t types 2012-05-03 03:28:38 -07:00
utsname.c userns: Use cred->user_ns instead of cred->user->user_ns 2012-04-07 16:55:51 -07:00
utsname_sysctl.c Merge branch 'modsplit-Oct31_2011' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux 2011-11-06 19:44:47 -08:00
wait.c lockdep/waitqueues: Add better annotation 2011-12-21 10:07:39 +01:00
watchdog.c Revert "NMI watchdog: fix for lockup detector breakage on resume" 2012-08-08 20:49:45 +02:00
workqueue.c workqueue: fix spurious CPU locality WARN from process_one_work() 2012-07-22 10:16:34 -07:00
workqueue_sched.h