Frederic Weisbecker
1f41906a6f
sched/fair: Correctly handle nohz ticks CPU load accounting ...
Ticks can happen while the CPU is in dynticks-idle or dynticks-singletask
mode. In fact "nohz" or "dynticks" only mean that we exit the periodic
mode and we try to minimize the ticks as much as possible. The nohz
subsystem uses a confusing terminology with the internal state
"ts->tick_stopped" which is also available through its public interface
with tick_nohz_tick_stopped(). This is a misnomer as the tick is instead
reduced with the best effort rather than stopped. In the best case the
tick can indeed be actually stopped but there is no guarantee about that.
If a timer needs to fire one second later, a tick will fire while the
CPU is in nohz mode and this is a very common scenario.
Now this confusion happens to be a problem with CPU load updates:
cpu_load_update_active() doesn't handle nohz ticks correctly because it
assumes that ticks are completely stopped in nohz mode and that
cpu_load_update_active() can't be called in dynticks mode. When that
happens, the whole previous tickless load is ignored and the function
just records the load for the current tick, ignoring potentially long
idle periods behind.
In order to solve this, we could account the current load for the
previous nohz time but there is a risk that we account the load of a
task that got freshly enqueued for the whole nohz period.
So instead, lets record the dynticks load on nohz frame entry so we know
what to record in case of nohz ticks, then use this record to account
the tickless load on nohz ticks and nohz frame end.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Byungchul Park <byungchul.park@lge.com>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Luiz Capitulino <lcapitulino@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul E . McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1460555812-25375-3-git-send-email-fweisbec@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-04-23 14:20:42 +02:00
bpf: add missing map_flags to bpf_map_show_fdinfo
2016-03-25 11:36:41 -04:00
mm/init: Add 'rodata=off' boot cmdline parameter to disable read-only kernel mappings
2016-02-22 08:51:37 +01:00
Merge branch 'PAGE_CACHE_SIZE-removal'
2016-04-04 10:50:24 -07:00
gcov: use within_module() helper.
2015-12-04 22:46:25 +01:00
kernel/...: convert pr_warning to pr_warn
2016-03-22 15:36:02 -07:00
livepatch/module: remove livepatch module notifier
2016-03-17 09:45:10 +01:00
locking/lockdep: Fix print_collision() unused warning
2016-04-04 11:41:34 +02:00
Power management and ACPI material for v4.6-rc1, part 2
2016-03-24 22:59:58 -07:00
printk: add clear_idx symbol to vmcoreinfo
2016-03-17 15:09:34 -07:00
kernel: add kcov code coverage
2016-03-22 15:36:02 -07:00
sched/fair: Correctly handle nohz ticks CPU load accounting
2016-04-23 14:20:42 +02:00
sched/fair: Correctly handle nohz ticks CPU load accounting
2016-04-23 14:20:42 +02:00
arch, ftrace: for KASAN put hard/soft IRQ entries into separate sections
2016-03-25 16:37:42 -07:00
async: export current_is_async()
2015-11-19 17:51:48 +01:00
Merge branch 'stable-4.6' of git://git.infradead.org/users/pcmoore/audit
2016-03-19 17:52:49 -07:00
security: Make inode argument of inode_getsecid non-const
2015-12-24 11:09:39 -05:00
wrappers for ->i_mutex access
2016-01-22 18:04:28 -05:00
audit: audit_tree_match can be boolean
2015-11-04 08:23:51 -05:00
Merge branch 'stable-4.6' of git://git.infradead.org/users/pcmoore/audit
2016-03-19 17:52:49 -07:00
audit: Fix typo in comment
2016-02-08 11:25:39 -05:00
auditsc: for seccomp events, log syscall compat state using in_compat_syscall
2016-03-22 15:36:02 -07:00
Merge branch 'for-4.6-ns' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
2016-03-21 10:05:13 -07:00
cgroup: kill cgrp_ss_priv[CGROUP_CANFORK_COUNT] and friends
2015-12-03 10:24:08 -05:00
cgroup_pids: fix a typo.
2015-12-14 14:54:37 -05:00
context_tracking: Switch to new static_branch API
2015-11-24 09:56:43 +01:00
cpu/hotplug: Document states better
2016-03-12 20:57:38 +01:00
Merge branch 'for-4.6-ns' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
2016-03-21 10:05:13 -07:00
kmemcg: account certain kmem allocations to memcg
2016-01-14 16:00:49 -08:00
kmemcg: account certain kmem allocations to memcg
2016-01-14 16:00:49 -08:00
oom: clear TIF_MEMDIE after oom_reaper managed to unmap the address space
2016-03-25 16:37:42 -07:00
kernel: add kcov code coverage
2016-03-22 15:36:02 -07:00
futex: Replace barrier() in unqueue_me() with READ_ONCE()
2016-03-08 17:04:02 +01:00
ptrace: use fsuid, fsgid, effective creds for fs access checks
2016-01-20 17:09:18 -08:00
kernel/hung_task.c: use timeout diff when timeout is updated
2016-03-22 15:36:02 -07:00
treewide: Remove old email address
2015-11-23 09:44:58 +01:00
treewide: Remove old email address
2015-11-23 09:44:58 +01:00
kallsyms: add support for relative offsets in kallsyms address table
2016-03-15 16:55:16 -07:00
ptrace: use fsuid, fsgid, effective creds for fs access checks
2016-01-20 17:09:18 -08:00
kernel: add kcov code coverage
2016-03-22 15:36:02 -07:00
kexec: set KEXEC_TYPE_CRASH before sanity_check_segment_list()
2016-01-20 17:09:18 -08:00
kexec: Set IORESOURCE_SYSTEM_RAM for System RAM
2016-01-30 09:49:57 +01:00
Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security
2016-03-17 11:33:45 -07:00
kexec: move some memembers and definitions within the scope of CONFIG_KEXEC_FILE
2016-01-20 17:09:18 -08:00
rcu: Remove TINY_RCU bloat from pointless boot parameters
2015-12-07 16:59:37 -08:00
sched/debug: Make schedstats a runtime tunable that is disabled by default
2016-02-09 11:54:23 +01:00
kernel: add kcov code coverage
2016-03-22 15:36:02 -07:00
memremap: add MEMREMAP_WC flag
2016-03-22 15:36:02 -07:00
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/livepatching
2016-03-17 21:46:32 -07:00
X.509: Make algo identifiers text instead of enum
2016-03-03 21:49:27 +00:00
cgroup: introduce cgroup namespaces
2016-02-16 13:04:58 -05:00
panic: change nmi_panic from macro to function
2016-03-22 15:36:02 -07:00
Nothing exciting, minor tweaks and cleanups.
2015-11-09 15:53:39 -08:00
Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2016-01-31 15:44:04 -08:00
profile: hide unused functions when !CONFIG_PROC_FS
2016-03-22 15:36:02 -07:00
ptrace: change __ptrace_unlink() to clear ->ptrace under ->siglock
2016-03-22 15:36:02 -07:00
wrappers for ->i_mutex access
2016-01-22 18:04:28 -05:00
/proc/iomem: only expose physical resource addresses to privileged users
2016-04-14 12:56:09 -07:00
seccomp: check in_compat_syscall, not is_compat_task, in strict mode
2016-03-22 15:36:02 -07:00
kernel/signal.c: add compile-time check for __ARCH_SI_PREAMBLE_SIZE
2016-03-22 15:36:02 -07:00
Merge branch 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2016-03-15 13:50:29 -07:00
cpu/hotplug: Unpark smpboot threads from the state machine
2016-03-01 20:36:56 +01:00
cpu/hotplug: Create hotplug threads
2016-03-01 20:36:56 +01:00
arch, ftrace: for KASAN put hard/soft IRQ entries into separate sections
2016-03-25 16:37:42 -07:00
kernel/stop_machine.c: remove CONFIG_SMP dependencies
2016-01-16 11:17:24 -08:00
timer: convert timer_slack_ns from unsigned long to u64
2016-03-17 15:09:34 -07:00
vfs: add copy_file_range syscall and vfs helper
2015-12-01 14:00:53 -05:00
mm: scale kswapd watermarks in proportion to memory
2016-03-17 15:09:34 -07:00
fs/coredump: prevent fsuid=0 dumps into user-controlled directories
2016-03-22 15:36:02 -07:00
kernel/...: convert pr_warning to pr_warn
2016-03-22 15:36:02 -07:00
time, acct: Drop irq save & restore from __acct_update_integrals()
2016-02-29 09:53:09 +01:00
kernel/*: switch to memdup_user_nul()
2016-01-04 10:27:55 -05:00
watchdog: don't run proc_watchdog_update if new value is same as old
2016-03-17 15:09:34 -07:00
Merge branch 'for-4.6' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq
2016-03-18 20:05:39 -07:00
sched/core: Get rid of 'cpu' argument in wq_worker_sleeping()
2016-03-02 10:28:47 -05:00
1f41906a6f