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Subject[RFC][PATCH 00/41] Nohz cpusets v3 (adaptive tickless kernel)
Date
Hi,

A summary of what this is about can be found here:
https://lkml.org/lkml/2011/8/15/245

Changes since v2:

* Correctly handle update of the cpuset mask when the nohz
flag is set (courtesy of Hakan Akkan)

* Handle rq clock. This introduces a new update_nohz_rq_clock()
helper that sites which make use of rq->clock can call if they want to
ensure the rq clock doesn't have a stale value due to the targeted CPU
beeing tickless. If it's tickless, it's not maintaining the rq clock
by calling scheduler_tick()->update_rq_clock() periodically.
I think I've added this manual call to every callsites that needed it.
I may have missed some though, or we may forget to handle tickless
CPUs in future code. So I think we need to add some automated debug checks
to catch that.

* Fix a warning reported by Gilad Ben Yossef: we flush the time on
pre-schedule and then the tick is restarted from an IPI before we do
it manually on post-schedule. From there we try to flush the time
again but ts->jiffies_saved_whence is set to SAVED_NONE because
we already flushed the time. This was triggering a spurious warning.

Still a lot to do. I'm now maintaining the TODO list there:
https://github.com/fweisbec/linux-dynticks/wiki/TODO

The git branch can be fetched from:

git://github.com/fweisbec/linux-dynticks.git
nohz/cpuset-v3


Frederic Weisbecker (40):
nohz: Separate idle sleeping time accounting from nohz logic
nohz: Make nohz API agnostic against idle ticks cputime accounting
nohz: Rename ts->idle_tick to ts->last_tick
nohz: Move nohz load balancer selection into idle logic
nohz: Move ts->idle_calls incrementation into strict idle logic
nohz: Move next idle expiry time record into idle logic area
cpuset: Set up interface for nohz flag
nohz: Try not to give the timekeeping duty to an adaptive tickless
cpu
x86: New cpuset nohz irq vector
nohz: Adaptive tick stop and restart on nohz cpuset
nohz/cpuset: Don't turn off the tick if rcu needs it
nohz/cpuset: Wake up adaptive nohz CPU when a timer gets enqueued
nohz/cpuset: Don't stop the tick if posix cpu timers are running
nohz/cpuset: Restart tick when nohz flag is cleared on cpuset
nohz/cpuset: Restart the tick if printk needs it
rcu: Restart the tick on non-responding adaptive nohz CPUs
rcu: Restart tick if we enqueue a callback in a nohz/cpuset CPU
nohz: Generalize tickless cpu time accounting
nohz/cpuset: Account user and system times in adaptive nohz mode
nohz/cpuset: New API to flush cputimes on nohz cpusets
nohz/cpuset: Flush cputime on threads in nohz cpusets when waiting
leader
nohz/cpuset: Flush cputimes on procfs stat file read
nohz/cpuset: Flush cputimes for getrusage() and times() syscalls
x86: Syscall hooks for nohz cpusets
x86: Exception hooks for nohz cpusets
x86: Add adaptive tickless hooks on do_notify_resume()
nohz: Don't restart the tick before scheduling to idle
sched: Comment on rq->clock correctness in ttwu_do_wakeup() in nohz
sched: Update rq clock on nohz CPU before migrating tasks
sched: Update rq clock on nohz CPU before setting fair group shares
sched: Update rq clock on tickless CPUs before calling
check_preempt_curr()
sched: Update rq clock earlier in unthrottle_cfs_rq
sched: Update clock of nohz busiest rq before balancing
sched: Update rq clock before idle balancing
sched: Update nohz rq clock before searching busiest group on load
balancing
rcu: New rcu_user_enter() and rcu_user_exit() APIs
rcu: New rcu_user_enter_irq() and rcu_user_exit_irq() APIs
rcu: Switch to extended quiescent state in userspace from nohz cpuset
nohz: Exit RCU idle mode when we schedule before resuming userspace
nohz/cpuset: Disable under some configs

Hakan Akkan (1):
nohz/cpuset: enable addition&removal of cpus while in adaptive nohz
mode

arch/Kconfig | 3 +
arch/x86/Kconfig | 1 +
arch/x86/include/asm/entry_arch.h | 3 +
arch/x86/include/asm/hw_irq.h | 7 +
arch/x86/include/asm/irq_vectors.h | 2 +
arch/x86/include/asm/smp.h | 11 +
arch/x86/include/asm/thread_info.h | 10 +-
arch/x86/kernel/entry_64.S | 12 +-
arch/x86/kernel/irqinit.c | 4 +
arch/x86/kernel/ptrace.c | 10 +
arch/x86/kernel/signal.c | 3 +
arch/x86/kernel/smp.c | 26 ++
arch/x86/kernel/traps.c | 20 +-
arch/x86/mm/fault.c | 13 +-
fs/proc/array.c | 2 +
include/linux/cpuset.h | 29 ++
include/linux/kernel_stat.h | 2 +
include/linux/posix-timers.h | 1 +
include/linux/rcupdate.h | 8 +
include/linux/sched.h | 10 +-
include/linux/tick.h | 75 ++++--
init/Kconfig | 8 +
kernel/cpuset.c | 141 +++++++++-
kernel/exit.c | 8 +
kernel/posix-cpu-timers.c | 12 +
kernel/printk.c | 15 +-
kernel/rcutree.c | 150 ++++++++--
kernel/sched/core.c | 112 ++++++++-
kernel/sched/fair.c | 39 +++-
kernel/sched/sched.h | 29 ++
kernel/softirq.c | 6 +-
kernel/sys.c | 6 +
kernel/time/tick-sched.c | 542 +++++++++++++++++++++++++++++-------
kernel/time/timer_list.c | 7 +-
kernel/timer.c | 2 +-
35 files changed, 1148 insertions(+), 181 deletions(-)

--
1.7.5.4



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