Paul E. McKenney
2da4b2a7fd
srcu: Expedite first synchronize_srcu() when idle
...
Classic SRCU in effect expedites the first synchronize_srcu() when SRCU
is idle, and Mike Galbraith demonstrated that some use cases do in fact
rely on this behavior. In particular, Mike showed that Steven Rostedt's
hotplug stress script takes 55 seconds with Classic SRCU and more than
16 -minutes- when running Tree SRCU. Assuming that each Tree SRCU's call
to synchronize_srcu() takes four milliseconds, this implies that Steven's
test invokes synchronize_srcu() in isolation, but more than once per
200 microseconds. Mike used ftrace to demonstrate that the time between
successive calls to synchronize_srcu() ranged from 118 to 342 microseconds,
with one outlier at 80 milliseconds. This data clearly indicates that
Tree SRCU needs to expedite the first invocation of synchronize_srcu()
during an SRCU idle period.
This commit therefor introduces a srcu_might_be_idle() function that
probabilistically checks whether or not SRCU is idle. This function is
used by synchronize_rcu() as an additional criterion in deciding whether
or not to expedite.
(Hat trick to Peter Zijlstra for his earlier suggestion that this might
in fact be a problem. Which for all I know might have motivated Mike to
look into it.)
Reported-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Mike Galbraith <efault@gmx.de>
2017-04-26 16:32:16 -07:00
..
bpf
bpf: fix checking xdp_adjust_head on tail calls
2017-04-17 15:51:57 -04:00
cgroup
Merge branch 'for-4.11-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
2017-04-16 11:48:10 -07:00
configs
config: android-base: enable hardened usercopy and kernel ASLR
2017-02-27 18:43:46 -08:00
debug
sched/headers: Prepare for new header dependencies before moving code to <linux/sched/debug.h>
2017-03-02 08:42:34 +01:00
events
Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2017-03-17 13:59:52 -07:00
gcov
irq
irq/affinity: Fix extra vecs calculation
2017-04-13 23:41:00 +02:00
livepatch
locking
Merge branch 'for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/rcu
2017-04-23 11:12:44 +02:00
power
Merge branch 'WIP.sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2017-03-03 10:16:38 -08:00
printk
sched/headers: Prepare for new header dependencies before moving code to <linux/sched/task_stack.h>
2017-03-02 08:42:36 +01:00
rcu
srcu: Expedite first synchronize_srcu() when idle
2017-04-26 16:32:16 -07:00
sched
Merge branch 'for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/rcu
2017-04-23 11:12:44 +02:00
time
Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2017-03-07 14:45:22 -08:00
trace
ring-buffer: Have ring_buffer_iter_empty() return true when empty
2017-04-19 21:23:47 -04:00
.gitignore
acct.c
sched/headers: Prepare to move cputime functionality from <linux/sched.h> into <linux/sched/cputime.h>
2017-03-02 08:42:39 +01:00
async.c
audit.c
audit: make sure we don't let the retry queue grow without bounds
2017-04-10 11:16:59 -04:00
audit.h
audit: move audit_signal_info() into kernel/auditsc.c
2017-03-27 14:30:06 -04:00
audit_fsnotify.c
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
2016-12-17 18:44:00 -08:00
audit_tree.c
Merge branch 'stable-4.10' of git://git.infradead.org/users/pcmoore/audit
2017-01-05 23:06:06 -08:00
audit_watch.c
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
2016-12-17 18:44:00 -08:00
auditfilter.c
auditsc.c
audit: move audit_signal_info() into kernel/auditsc.c
2017-03-27 14:30:06 -04:00
backtracetest.c
bounds.c
capability.c
capability: export has_capability
2017-01-12 07:01:56 -07:00
compat.c
Replace <asm/uaccess.h> with <linux/uaccess.h> globally
2016-12-24 11:46:01 -08:00
configs.c
Replace <asm/uaccess.h> with <linux/uaccess.h> globally
2016-12-24 11:46:01 -08:00
context_tracking.c
cpu.c
cpu/hotplug: Serialize callback invocations proper
2017-03-14 19:19:27 +01:00
cpu_pm.c
crash_dump.c
cred.c
sched/headers: Prepare for new header dependencies before moving code to <linux/sched/coredump.h>
2017-03-02 08:42:28 +01:00
delayacct.c
sched/headers: Prepare to move cputime functionality from <linux/sched.h> into <linux/sched/cputime.h>
2017-03-02 08:42:39 +01:00
dma.c
elfcore.c
exec_domain.c
exit.c
userfaultfd: non-cooperative: rollback userfaultfd_exit
2017-03-09 17:01:09 -08:00
extable.c
Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next
2017-02-22 10:15:09 -08:00
fork.c
mm: Rename SLAB_DESTROY_BY_RCU to SLAB_TYPESAFE_BY_RCU
2017-04-18 11:42:36 -07:00
freezer.c
futex.c
futex: Add missing error handling to FUTEX_REQUEUE_PI
2017-03-14 21:45:36 +01:00
futex_compat.c
Replace <asm/uaccess.h> with <linux/uaccess.h> globally
2016-12-24 11:46:01 -08:00
groups.c
Replace <asm/uaccess.h> with <linux/uaccess.h> globally
2016-12-24 11:46:01 -08:00
hung_task.c
sched/headers: Prepare for new header dependencies before moving code to <linux/sched/debug.h>
2017-03-02 08:42:34 +01:00
irq_work.c
jump_label.c
This release has no new tracing features, just clean ups, minor fixes
2017-02-27 13:26:17 -08:00
kallsyms.c
bpf: make jited programs visible in traces
2017-02-17 13:40:05 -05:00
kcmp.c
Kconfig.freezer
Kconfig.hz
Kconfig.locks
Kconfig.preempt
kcov.c
kcov: make kcov work properly with KASLR enabled
2016-12-20 09:48:47 -08:00
kexec.c
kexec_core.c
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk
2017-02-22 17:33:34 -08:00
kexec_file.c
kexec, x86/purgatory: Unbreak it and clean it up
2017-03-10 20:55:09 +01:00
kexec_internal.h
kexec, x86/purgatory: Unbreak it and clean it up
2017-03-10 20:55:09 +01:00
kmod.c
sched/headers, vfs/execve: Prepare to move the do_execve*() prototypes from <linux/sched.h> to <linux/binfmts.h>
2017-03-02 08:42:39 +01:00
kprobes.c
powerpc updates for 4.11 part 1.
2017-02-22 10:30:38 -08:00
ksysfs.c
kernel/ksysfs.c: add __ro_after_init to bin_attribute structure
2017-02-24 17:46:56 -08:00
kthread.c
cgroup, kthread: close race window where new kthreads can be migrated to non-root cgroups
2017-03-17 10:18:47 -04:00
latencytop.c
sched/headers: Prepare to move sched_info_on() and force_schedstat_enabled() from <linux/sched.h> to <linux/sched/stat.h>
2017-03-02 08:42:39 +01:00
Makefile
cgroup: move cgroup files under kernel/cgroup/
2016-12-27 14:49:05 -05:00
membarrier.c
Fix: Disable sys_membarrier when nohz_full is enabled
2017-01-23 11:32:16 -08:00
memremap.c
mm: add private lock to serialize memory hotplug operations
2017-03-16 16:56:18 -07:00
module-internal.h
module.c
Modules updates for v4.11
2017-02-22 17:08:33 -08:00
module_signing.c
notifier.c
kernel/notifier.c: simplify expression
2017-02-24 17:46:56 -08:00
nsproxy.c
padata.c
padata: avoid race in reordering
2017-03-24 21:51:33 +08:00
panic.c
sched/headers: Prepare for new header dependencies before moving code to <linux/sched/debug.h>
2017-03-02 08:42:34 +01:00
params.c
pid.c
sched/headers: Prepare for new header dependencies before moving code to <linux/sched/task.h>
2017-03-02 08:42:35 +01:00
pid_namespace.c
sched/headers: Prepare for the reduction of <linux/sched.h>'s signal API dependency
2017-03-02 08:42:37 +01:00
profile.c
sched/headers: Prepare to move sched_info_on() and force_schedstat_enabled() from <linux/sched.h> to <linux/sched/stat.h>
2017-03-02 08:42:39 +01:00
ptrace.c
ptrace: fix PTRACE_LISTEN race corrupting task->state
2017-04-08 00:47:48 -07:00
range.c
reboot.c
relay.c
lib/vsprintf.c: remove %Z support
2017-02-27 18:43:47 -08:00
resource.c
seccomp.c
sched/headers: Prepare for new header dependencies before moving code to <linux/sched/task_stack.h>
2017-03-02 08:42:36 +01:00
signal.c
mm: Rename SLAB_DESTROY_BY_RCU to SLAB_TYPESAFE_BY_RCU
2017-04-18 11:42:36 -07:00
smp.c
sched/headers: Prepare for new header dependencies before moving code to <linux/sched/idle.h>
2017-03-02 08:42:26 +01:00
smpboot.c
sched/headers: Prepare for new header dependencies before moving code to <linux/sched/task.h>
2017-03-02 08:42:35 +01:00
smpboot.h
softirq.c
stacktrace.c
stacktrace, lockdep: Fix address, newline ugliness
2017-02-08 08:21:31 +01:00
stop_machine.c
sys.c
sched/headers: Prepare to move cputime functionality from <linux/sched.h> into <linux/sched/cputime.h>
2017-03-02 08:42:39 +01:00
sys_ni.c
move aio compat to fs/aio.c
2016-12-22 22:58:37 -05:00
sysctl.c
sysctl: report EINVAL if value is larger than UINT_MAX for proc_douintvec
2017-04-08 10:27:40 -07:00
sysctl_binary.c
sysctl: add KERN_CONT to deprecated_sysctl_warning()
2016-12-14 16:04:07 -08:00
task_work.c
taskstats.c
test_kprobes.c
torture.c
sched/headers: Prepare for new header dependencies before moving code to <linux/sched/clock.h>
2017-03-02 08:42:27 +01:00
tracepoint.c
sched/headers: Prepare for new header dependencies before moving code to <linux/sched/task.h>
2017-03-02 08:42:35 +01:00
tsacct.c
sched/headers: Prepare to move cputime functionality from <linux/sched.h> into <linux/sched/cputime.h>
2017-03-02 08:42:39 +01:00
ucount.c
ucount: Remove the atomicity from ucount->count
2017-03-06 15:26:37 -06:00
uid16.c
sched/headers: Prepare to remove <linux/cred.h> inclusion from <linux/sched.h>
2017-03-02 08:42:31 +01:00
up.c
user-return-notifier.c
user.c
sched/headers: Prepare for new header dependencies before moving code to <linux/sched/user.h>
2017-03-02 08:42:29 +01:00
user_namespace.c
sched/headers: Prepare for new header dependencies before moving code to <linux/sched/signal.h>
2017-03-02 08:42:29 +01:00
utsname.c
sched/headers: Prepare to move the task_lock()/unlock() APIs to <linux/sched/task.h>
2017-03-02 08:42:38 +01:00
utsname_sysctl.c
sched/headers: Remove <linux/rwsem.h> from <linux/sched.h>
2017-03-03 01:45:36 +01:00
watchdog.c
sched/headers: Prepare for new header dependencies before moving code to <linux/sched/debug.h>
2017-03-02 08:42:34 +01:00
watchdog_hld.c
sched/headers: Prepare for new header dependencies before moving code to <linux/sched/debug.h>
2017-03-02 08:42:34 +01:00
workqueue.c
workqueue: trigger WARN if queue_delayed_work() is called with NULL @wq
2017-03-06 15:33:42 -05:00
workqueue_internal.h