linux/kernel
Venki Pallipadi 6e453a6751 Add support for deferrable timers
Introduce a new flag for timers - deferrable: Timers that work normally
when system is busy.  But, will not cause CPU to come out of idle (just to
service this timer), when CPU is idle.  Instead, this timer will be
serviced when CPU eventually wakes up with a subsequent non-deferrable
timer.

The main advantage of this is to avoid unnecessary timer interrupts when
CPU is idle.  If the routine currently called by a timer can wait until
next event without any issues, this new timer can be used to setup timer
event for that routine.  This, with dynticks, allows CPUs to be lazy,
allowing them to stay in idle for extended period of time by reducing
unnecesary wakeup and thereby reducing the power consumption.

This patch:

Builds this new timer on top of existing timer infrastructure.  It uses
last bit in 'base' pointer of timer_list structure to store this deferrable
timer flag.  __next_timer_interrupt() function skips over these deferrable
timers when CPU looks for next timer event for which it has to wake up.

This is exported by a new interface init_timer_deferrable() that can be
called in place of regular init_timer().

[akpm@linux-foundation.org: Privatise a #define]
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Dave Jones <davej@codemonkey.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-08 11:15:05 -07:00
..
irq kernel/irq/proc.c: unprotected iteration over the IRQ action list in name_unique() 2007-05-08 11:15:05 -07:00
power freezer: task->exit_state should be treated as bolean 2007-05-08 11:14:58 -07:00
time [PATCH] fix jiffies clocksource inittime 2007-04-04 21:12:47 -07:00
.gitignore
Kconfig.hz [PATCH] HZ: 300Hz support 2006-12-07 08:39:36 -08:00
Kconfig.preempt
Makefile move die notifier handling to common code 2007-05-08 11:15:04 -07:00
acct.c [PATCH] kernel: change uses of f_{dentry, vfsmnt} to use f_path 2006-12-08 08:28:42 -08:00
audit.c [NETLINK]: Switch cb_lock spinlock to mutex and allow to override it 2007-04-25 22:29:03 -07:00
audit.h
auditfilter.c [PATCH] minor update to rule add/delete messages (ver 2) 2007-02-17 21:30:09 -05:00
auditsc.c [PATCH] fix deadlock in audit_log_task_context() 2007-03-14 15:27:48 -07:00
capability.c [PATCH] pid: replace do/while_each_task_pid with do/while_each_pid_task 2007-02-12 09:48:32 -08:00
compat.c [PATCH] Common compat_sys_sysinfo 2007-02-11 10:51:32 -08:00
configs.c [PATCH] struct seq_operations and struct file_operations constification 2006-12-07 08:39:46 -08:00
cpu.c [PATCH] Fix microcode-related suspend problem 2007-04-02 10:06:09 -07:00
cpuset.c Fix race between attach_task and cpuset_exit 2007-05-08 11:15:05 -07:00
delayacct.c KMEM_CACHE(): simplify slab cache creation 2007-05-07 12:12:55 -07:00
die_notifier.c move die notifier handling to common code 2007-05-08 11:15:04 -07:00
dma.c [PATCH] struct seq_operations and struct file_operations constification 2006-12-07 08:39:46 -08:00
exec_domain.c
exit.c Return EPERM not ECHILD on security_task_wait failure 2007-05-07 12:12:57 -07:00
extable.c
fork.c Merge sys_clone()/sys_unshare() nsproxy and namespace handling 2007-05-08 11:15:00 -07:00
futex.c futex: restartable futex_wait 2007-05-08 11:15:03 -07:00
futex_compat.c [PATCH] __user annotations: futex 2006-10-10 15:37:22 -07:00
hrtimer.c [NET]: Fix networking compilation errors 2007-04-27 15:31:24 -07:00
itimer.c [PATCH] hrtimers: prevent possible itimer DoS 2007-02-16 08:13:59 -08:00
kallsyms.c Extend print_symbol capability 2007-04-30 16:40:39 -07:00
kexec.c Merge branch 'release' of master.kernel.org:/pub/scm/linux/kernel/git/aegl/linux-2.6 2006-12-07 15:39:22 -08:00
kfifo.c [PATCH] Numerous fixes to kernel-doc info in source files. 2007-02-11 10:51:32 -08:00
kmod.c Revert "Driver core: let request_module() send a /sys/modules/kmod/-uevent" 2007-02-23 14:54:57 -08:00
kprobes.c move die notifier handling to common code 2007-05-08 11:15:04 -07:00
ksysfs.c remove "struct subsystem" as it is no longer needed 2007-05-02 18:57:59 -07:00
kthread.c [PATCH] Numerous fixes to kernel-doc info in source files. 2007-02-11 10:51:32 -08:00
latency.c [PATCH] severing module.h->sched.h 2006-12-04 02:00:22 -05:00
lockdep.c simplify the stacktrace code 2007-05-08 11:14:58 -07:00
lockdep_internals.h [PATCH] lockdep: more chains 2006-12-07 08:39:43 -08:00
lockdep_proc.c [PATCH] remove many unneeded #includes of sched.h 2007-02-14 08:09:54 -08:00
module.c module: use krealloc 2007-05-08 11:15:00 -07:00
mutex-debug.c [PATCH] remove many unneeded #includes of sched.h 2007-02-14 08:09:54 -08:00
mutex-debug.h
mutex.c [PATCH] lockdep: avoid lockdep warning in md 2006-12-08 08:28:39 -08:00
mutex.h
nsproxy.c Merge sys_clone()/sys_unshare() nsproxy and namespace handling 2007-05-08 11:15:00 -07:00
panic.c [PATCH] Add TAINT_USER and ability to set taint flags from userspace 2007-02-11 10:51:29 -08:00
params.c remove "struct subsystem" as it is no longer needed 2007-05-02 18:57:59 -07:00
pid.c Merge sys_clone()/sys_unshare() nsproxy and namespace handling 2007-05-08 11:15:00 -07:00
posix-cpu-timers.c [PATCH] posix timers: RCU optimization for clock_gettime() 2007-02-16 08:14:00 -08:00
posix-timers.c [PATCH] hrtimers: add high resolution timer support 2007-02-16 08:13:59 -08:00
printk.c Fixes and cleanups for earlyprintk aka boot console 2007-05-08 11:15:04 -07:00
profile.c [PATCH] proc: remove useless (and buggy) ->nlink settings 2007-02-11 10:51:32 -08:00
ptrace.c
rcupdate.c [PATCH] rcu: add a prefetch() in rcu_do_batch() 2006-12-07 08:39:40 -08:00
rcutorture.c rcutorture: Mark rcu_torture_init as __init 2007-05-08 11:15:00 -07:00
relay.c [PATCH] kernel-doc fixes for 2.6.20-git15 (non-drivers) 2007-03-01 14:53:37 -08:00
resource.c libata/IDE: remove combined mode quirk 2007-04-28 14:15:59 -04:00
rtmutex-debug.c Remove all inclusions of <linux/config.h> 2006-10-04 03:38:54 -04:00
rtmutex-debug.h
rtmutex-tester.c [PATCH] Add include/linux/freezer.h and move definitions from sched.h 2006-12-07 08:39:27 -08:00
rtmutex.c [PATCH] hrtimers: namespace and enum cleanup 2007-02-16 08:13:58 -08:00
rtmutex.h
rtmutex_common.h
rwsem.c
sched.c Safer nr_node_ids and nr_node_ids determination and initial values 2007-05-07 12:12:51 -07:00
seccomp.c
signal.c KMEM_CACHE(): simplify slab cache creation 2007-05-07 12:12:55 -07:00
softirq.c [PATCH] tick-management: dyntick / highres functionality 2007-02-16 08:13:59 -08:00
softlockup.c softlockup: s/99/MAX_RT_PRIO/ 2007-05-08 11:14:59 -07:00
spinlock.c [PATCH] lockdep: spin_lock_irqsave_nested() 2006-11-25 13:28:34 -08:00
srcu.c [PATCH] SRCU: report out-of-memory errors 2006-10-04 07:55:30 -07:00
stacktrace.c
stop_machine.c Use stop_machine_run in the Intel RNG driver 2007-05-08 11:15:00 -07:00
sys.c remove software_suspend() 2007-05-07 12:12:59 -07:00
sys_ni.c [PATCH] Create compat_sys_migrate_pages 2006-11-03 12:27:59 -08:00
sysctl.c proc: maps protection 2007-05-08 11:15:02 -07:00
taskstats.c KMEM_CACHE(): simplify slab cache creation 2007-05-07 12:12:55 -07:00
time.c Optimize timespec_trunc() 2007-05-08 11:15:01 -07:00
timer.c Add support for deferrable timers 2007-05-08 11:15:05 -07:00
tsacct.c [PATCH] time: x86_64: split x86_64/kernel/time.c up 2007-02-16 08:14:00 -08:00
uid16.c
user.c [PATCH] slab: remove kmem_cache_t 2006-12-07 08:39:25 -08:00
utsname.c Merge sys_clone()/sys_unshare() nsproxy and namespace handling 2007-05-08 11:15:00 -07:00
utsname_sysctl.c [PATCH] sysctl: remove insert_at_head from register_sysctl 2007-02-14 08:09:59 -08:00
wait.c
workqueue.c [PATCH] Add debugging feature /proc/timer_stat 2007-02-16 08:13:59 -08:00