Paul E. McKenney
12f54c3a84
rcu/nocb: Provide separate no-CBs grace-period kthreads ...
Currently, there is one no-CBs rcuo kthread per CPU, and these kthreads
are divided into groups. The first rcuo kthread to come online in a
given group is that group's leader, and the leader both waits for grace
periods and invokes its CPU's callbacks. The non-leader rcuo kthreads
only invoke callbacks.
This works well in the real-time/embedded environments for which it was
intended because such environments tend not to generate all that many
callbacks. However, given huge floods of callbacks, it is possible for
the leader kthread to be stuck invoking callbacks while its followers
wait helplessly while their callbacks pile up. This is a good recipe
for an OOM, and rcutorture's new callback-flood capability does generate
such OOMs.
One strategy would be to wait until such OOMs start happening in
production, but similar OOMs have in fact happened starting in 2018.
It would therefore be wise to take a more proactive approach.
This commit therefore features per-CPU rcuo kthreads that do nothing
but invoke callbacks. Instead of having one of these kthreads act as
leader, each group has a separate rcog kthread that handles grace periods
for its group. Because these rcuog kthreads do not invoke callbacks,
callback floods on one CPU no longer block callbacks from reaching the
rcuc callback-invocation kthreads on other CPUs.
This change does introduce additional kthreads, however:
1. The number of additional kthreads is about the square root of
the number of CPUs, so that a 4096-CPU system would have only
about 64 additional kthreads. Note that recent changes
decreased the number of rcuo kthreads by a factor of two
(CONFIG_PREEMPT=n) or even three (CONFIG_PREEMPT=y), so
this still represents a significant improvement on most systems.
2. The leading "rcuo" of the rcuog kthreads should allow existing
scripting to affinity these additional kthreads as needed, the
same as for the rcuop and rcuos kthreads. (There are no longer
any rcuob kthreads.)
3. A state-machine approach was considered and rejected. Although
this would allow the rcuo kthreads to continue their dual
leader/follower roles, it complicates callback invocation
and makes it more difficult to consolidate rcuo callback
invocation with existing softirq callback invocation.
The introduction of rcuog kthreads should thus be acceptable.
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
2019-08-13 14:32:39 -07:00
Merge branch 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2019-07-20 10:45:15 -07:00
Merge branch 'work.mount0' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
2019-07-19 10:42:02 -07:00
treewide: Add SPDX license identifier - Makefile/Kconfig
2019-05-21 10:50:46 +02:00
dma-mapping fixes for 5.3-rc1
2019-07-20 12:09:52 -07:00
perf/core: Fix creating kernel counters for PMUs that override event->cpu
2019-07-25 15:41:31 +02:00
gcov: no need to check return value of debugfs_create functions
2019-06-03 16:18:12 +02:00
Merge branch 'x86-apic-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2019-07-08 11:22:57 -07:00
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/livepatching/livepatching
2019-07-11 15:30:05 -07:00
lockdep: Make print_lock() address visible
2019-08-01 14:05:51 -07:00
pci-v5.3-changes
2019-07-15 20:44:49 -07:00
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 13
2019-05-21 11:28:45 +02:00
rcu/nocb: Provide separate no-CBs grace-period kthreads
2019-08-13 14:32:39 -07:00
idle: Prevent late-arriving interrupts from disrupting offline
2019-08-12 11:23:56 -07:00
timekeeping/vsyscall: Use __iter_div_u64_rem()
2019-07-10 20:37:49 +02:00
treewide: Rename rcu_dereference_raw_notrace() to _check()
2019-08-01 14:16:21 -07:00
Provide in-kernel headers to make extending kernel easier
2019-04-29 16:48:03 +02:00
acct_on(): don't mess with freeze protection
2019-04-04 21:04:13 -04:00
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 441
2019-06-05 17:37:17 +02:00
audit/stable-5.3 PR 20190702
2019-07-08 18:55:42 -07:00
audit/stable-5.3 PR 20190702
2019-07-08 18:55:42 -07:00
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157
2019-05-30 11:26:37 -07:00
fsnotify: switch send_to_group() and ->handle_event to const struct qstr *
2019-04-26 13:51:03 -04:00
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156
2019-05-30 11:26:35 -07:00
audit/stable-5.3 PR 20190702
2019-07-08 18:55:42 -07:00
audit: enforce op for string fields
2019-05-28 17:46:43 -04:00
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 441
2019-06-05 17:37:17 +02:00
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500
2019-06-19 17:09:55 +02:00
kernel/configs: use .incbin directive to embed config_data.gz
2019-03-07 18:32:02 -08:00
treewide: Add SPDX license identifier for missed files
2019-05-21 10:50:45 +02:00
Merge branch 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2019-07-08 10:39:56 -07:00
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 282
2019-06-05 17:36:37 +02:00
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 230
2019-06-19 17:09:06 +02:00
treewide: Add SPDX license identifier for missed files
2019-05-21 10:50:45 +02:00
Merge branch 'access-creds'
2019-07-25 08:36:29 -07:00
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 25
2019-05-21 11:52:39 +02:00
pidfd: fix a poll race when setting exit_state
2019-07-22 16:02:03 +02:00
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156
2019-05-30 11:26:35 -07:00
fail_function: no need to check return value of debugfs_create functions
2019-06-03 15:49:06 +02:00
sched/fair: Don't free p->numa_faults with concurrent readers
2019-07-25 15:37:04 +02:00
treewide: Add SPDX license identifier for missed files
2019-05-21 10:50:45 +02:00
Linux 5.2-rc3
2019-06-03 11:50:18 +02:00
kheaders: include only headers into kheaders_data.tar.xz
2019-07-09 10:10:52 +09:00
treewide: Add SPDX license identifier for missed files
2019-05-21 10:50:45 +02:00
mm/nvdimm: add is_ioremap_addr and use that to check ioremap address
2019-07-12 11:05:40 -07:00
treewide: Add SPDX license identifier for missed files
2019-05-21 10:50:45 +02:00
jump_label: Batch updates if arch supports it
2019-06-17 12:09:22 +02:00
treewide: Add SPDX license identifier for missed files
2019-05-21 10:50:45 +02:00
treewide: Add SPDX license identifier - Makefile/Kconfig
2019-05-21 10:50:46 +02:00
treewide: Add SPDX license identifier - Makefile/Kconfig
2019-05-21 10:50:46 +02:00
treewide: Add SPDX license identifier - Makefile/Kconfig
2019-05-21 10:50:46 +02:00
sched/rt, Kconfig: Unbreak def/oldconfig with CONFIG_PREEMPT=y
2019-07-22 18:05:11 +02:00
kcov: convert kcov.refcount to refcount_t
2019-03-07 18:32:02 -08:00
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 230
2019-06-19 17:09:06 +02:00
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 230
2019-06-19 17:09:06 +02:00
Merge branch 'next-integrity' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity
2019-07-08 20:28:59 -07:00
kheaders: Move from proc to sysfs
2019-05-24 20:16:01 +02:00
The main changes in this release include:
2019-07-18 11:51:00 -07:00
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 170
2019-05-30 11:26:39 -07:00
treewide: Add SPDX license identifier for missed files
2019-05-21 10:50:45 +02:00
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 441
2019-06-05 17:37:17 +02:00
kheaders: Move from proc to sysfs
2019-05-24 20:16:01 +02:00
mm/devm_memremap_pages: enable sub-section remap
2019-07-18 17:08:07 -07:00
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 36
2019-05-24 17:27:11 +02:00
Modules updates for v5.3
2019-07-18 12:06:57 -07:00
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 36
2019-05-24 17:27:11 +02:00
treewide: Add SPDX license identifier for missed files
2019-05-21 10:50:45 +02:00
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 441
2019-06-05 17:37:17 +02:00
padata: use smp_mb in padata_reorder to avoid orphaned padata jobs
2019-07-18 13:39:54 +08:00
docs: admin-guide: move sysctl directory to it
2019-07-15 11:03:01 -03:00
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156
2019-05-30 11:26:35 -07:00
kernel/pid.c: convert struct pid count to refcount_t
2019-07-16 19:23:24 -07:00
proc/sysctl: add shared variables for range check
2019-07-18 17:08:07 -07:00
treewide: Add SPDX license identifier for missed files
2019-05-21 10:50:45 +02:00
ptrace: add PTRACE_GET_SYSCALL_INFO request
2019-07-16 19:23:24 -07:00
treewide: Add SPDX license identifier for missed files
2019-05-21 10:50:45 +02:00
Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
2019-03-12 13:27:20 -07:00
resource: avoid unnecessary lookups in find_next_iomem_res()
2019-07-18 17:08:06 -07:00
signal: Remove task parameter from force_sig
2019-05-27 09:36:28 -05:00
signal: Remove the signal number and task parameters from force_sig_info
2019-05-29 09:31:44 -05:00
signal: simplify set_user_sigmask/restore_user_sigmask
2019-07-16 19:23:24 -07:00
smp: Warn on function calls from softirq context
2019-07-20 11:27:16 +02:00
treewide: Add SPDX license identifier for missed files
2019-05-21 10:50:45 +02:00
Merge branch 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2019-07-08 11:01:13 -07:00
stacktrace: Force USER_DS for stack_trace_save_user()
2019-07-18 16:47:24 +02:00
processor: get rid of cpu_relax_yield
2019-06-15 12:25:55 +02:00
prctl_set_mm: downgrade mmap_sem to read lock
2019-06-01 15:51:31 -07:00
arch: handle arches who do not yet define clone3
2019-06-21 01:54:53 +02:00
proc/sysctl: add shared variables for range check
2019-07-18 17:08:07 -07:00
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157
2019-05-30 11:26:37 -07:00
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 25
2019-05-21 11:52:39 +02:00
torture: Remove exporting of internal functions
2019-08-01 14:30:22 -07:00
The main changes in this release include:
2019-07-18 11:51:00 -07:00
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157
2019-05-30 11:26:37 -07:00
proc/sysctl: add shared variables for range check
2019-07-18 17:08:07 -07:00
treewide: Add SPDX license identifier for missed files
2019-05-21 10:50:45 +02:00
smp: Remove smp_call_function() and on_each_cpu() return values
2019-06-23 14:26:26 +02:00
treewide: Add SPDX license identifier for missed files
2019-05-21 10:50:45 +02:00
Keyrings namespacing
2019-07-08 19:36:47 -07:00
Keyrings namespacing
2019-07-08 19:36:47 -07:00
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 441
2019-06-05 17:37:17 +02:00
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 441
2019-06-05 17:37:17 +02:00
watchdog: Fix typo in comment
2019-04-18 14:05:51 +02:00
kernel/watchdog_hld.c: hard lockup message should end with a newline
2019-04-19 09:46:05 -07:00
workqueue: Remove GPF argument from alloc_workqueue_attrs()
2019-06-27 14:12:19 -07:00
sched/core, workqueues: Distangle worker accounting from rq lock
2019-04-16 16:55:15 +02:00
12f54c3a84