Stephan Baerwolf db670dac49 sched: Fix and optimise calculation of the weight-inverse ...

If the inverse loadweight should be zero, function "calc_delta_mine"
calculates the inverse of "lw->weight" (in 32bit integer ops).

This calculation is actually a little bit impure (because it is
inverting something around "lw-weight"+1), especially when
"lw->weight" becomes smaller.

The correct inverse would be 1/lw->weight multiplied by
"WMULT_CONST" for fixcomma-scaling it into integers.
(So WMULT_CONST/lw->weight ...)

The old, impure algorithm took two divisions for inverting lw->weight,
the new, more exact one only takes one and an additional unlikely-if.

Signed-off-by: Stephan Baerwolf <stephan.baerwolf@tu-ilmenau.de>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/n/tip-0pz0wnyalr4tk4ln11xwumdx@git.kernel.org
[ This could explain some aritmetical issues for small shares but nothing
  concrete has been reported yet so we are not confident enough to queue
  this up in sched/urgent and for -stable backport. But if anyone finds
  this commit and sees it to fix some badness then we can certainly
  change our mind! ]
Signed-off-by: Ingo Molnar <mingo@elte.hu>

2011-05-16 11:01:18 +02:00

..

debug

Fix common misspellings

2011-03-31 11:26:23 -03:00

gcov

Merge branch 'trivial' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild-2.6

2011-03-20 18:14:55 -07:00

irq

genirq: Fix typo CONFIG_GENIRC_IRQ_SHOW_LEVEL

2011-05-02 21:16:37 +02:00

power

PM: Fix error code paths executed after failing syscore_suspend()

2011-04-18 23:58:59 +02:00

time

posix clocks: Replace mutex with reader/writer semaphore

2011-04-18 10:39:38 +02:00

trace

Merge commit 'v2.6.39-rc7' into sched/core

2011-05-12 09:36:18 +02:00

.gitignore

…

acct.c

pass a struct path to vfs_statfs

2010-08-09 16:48:42 -04:00

async.c

async: use workqueue for worker pool

2010-07-14 11:29:46 +02:00

audit_tree.c

Fix common misspellings

2011-03-31 11:26:23 -03:00

audit_watch.c

kill path_lookup()

2011-03-14 09:15:23 -04:00

audit.c

netlink: kill loginuid/sessionid/sid members from struct netlink_skb_parms

2011-03-03 10:55:40 -08:00

audit.h

audit: make functions static

2010-10-30 01:42:19 -04:00

auditfilter.c

netlink: kill loginuid/sessionid/sid members from struct netlink_skb_parms

2011-03-03 10:55:40 -08:00

auditsc.c

Fix common misspellings

2011-03-31 11:26:23 -03:00

backtracetest.c

…

bounds.c

memcg: remove direct page_cgroup-to-page pointer

2011-03-23 19:46:28 -07:00

capability.c

userns: make has_capability* into real functions

2011-03-23 19:47:06 -07:00

cgroup_freezer.c

cgroup_freezer: update_freezer_state() does incorrect state transitions

2010-10-27 18:03:08 -07:00

cgroup.c

Fix common misspellings

2011-03-31 11:26:23 -03:00

compat.c

posix-timers: Introduce a syscall for clock tuning.

2011-02-02 15:28:19 +01:00

configs.c

llseek: automatically add .llseek fop

2010-10-15 15:53:27 +02:00

cpu.c

Fix common misspellings

2011-03-31 11:26:23 -03:00

cpuset.c

sched: Dynamic sched_domain::level

2011-04-11 14:09:32 +02:00

crash_dump.c

crash_dump: export is_kdump_kernel to modules, consolidate elfcorehdr_addr, setup_elfcorehdr and saved_max_pfn

2011-03-23 19:47:19 -07:00

cred.c

userns: security: make capabilities relative to the user namespace

2011-03-23 19:47:02 -07:00

delayacct.c

…

dma.c

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elfcore.c

elf coredump: add extended numbering support

2010-03-06 11:26:46 -08:00

exec_domain.c

sys_personality: remove the bogus checks in sys_personality()->__set_personality() path

2010-08-09 20:45:05 -07:00

exit.c

ptrace: Prepare to fix racy accesses on task breakpoints

2011-04-25 17:28:24 +02:00

extable.c

…

fork.c

sched: Remove unused parameters from sched_fork() and wake_up_new_task()

2011-05-12 09:36:37 +02:00

freezer.c

Freezer: Fix a race during freezing of TASK_STOPPED tasks

2010-12-24 15:02:40 +01:00

futex_compat.c

userns: user namespaces: convert several capable() calls

2011-03-23 19:47:08 -07:00

futex.c

futex: Set FLAGS_HAS_TIMEOUT during futex_wait restart setup

2011-04-15 16:34:32 +02:00

groups.c

userns: user namespaces: convert several capable() calls

2011-03-23 19:47:08 -07:00

hrtimer.c

hrtimer: Initialize CLOCK_ID to HRTIMER_BASE table statically

2011-04-29 10:57:11 +02:00

hung_task.c

lockup detector: Fix grammar by adding a missing "to" in the comments

2010-08-17 09:11:52 +02:00

hw_breakpoint.c

perf: Dynamic pmu types

2010-12-16 11:36:43 +01:00

irq_work.c

irq_work: Use per cpu atomics instead of regular atomics

2010-12-18 15:54:48 +01:00

itimer.c

…

jump_label.c

jump label: Make arch_jump_label_text_poke_early() optional

2010-10-29 12:56:13 -04:00

kallsyms.c

Merge branch 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

2011-03-25 17:52:22 -07:00

Kconfig.freezer

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Kconfig.hz

…

Kconfig.locks

…

Kconfig.preempt

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kexec.c

PM: Add missing syscore_suspend() and syscore_resume() calls

2011-04-20 00:36:11 +02:00

kfifo.c

kfifo: fix scatterlist usage

2010-10-01 10:50:58 -07:00

kmod.c

Make do_execve() take a const filename pointer

2010-08-17 18:07:43 -07:00

kprobes.c

Merge branch 'for-2.6.38' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu

2011-01-07 17:02:58 -08:00

ksysfs.c

sysfs: add struct file* to bin_attr callbacks

2010-05-21 09:37:31 -07:00

kthread.c

Fix common misspellings

2011-03-31 11:26:23 -03:00

latencytop.c

Fix common misspellings

2011-03-31 11:26:23 -03:00

lockdep_internals.h

lockdep: No need to disable preemption in debug atomic ops

2010-05-04 05:38:16 +02:00

lockdep_proc.c

lockdep: Remove unused 'factor' variable from lockdep_stats_show()

2011-03-23 13:54:47 +01:00

lockdep_states.h

…

lockdep.c

Fix common misspellings

2011-03-31 11:26:23 -03:00

Makefile

crash_dump: export is_kdump_kernel to modules, consolidate elfcorehdr_addr, setup_elfcorehdr and saved_max_pfn

2011-03-23 19:47:19 -07:00

module.c

Fix common misspellings

2011-03-31 11:26:23 -03:00

mutex-debug.c

mutex: Use p->on_cpu for the adaptive spin

2011-04-14 08:52:33 +02:00

mutex-debug.h

mutex: Use p->on_cpu for the adaptive spin

2011-04-14 08:52:33 +02:00

mutex.c

sched: Get rid of lock_depth

2011-04-24 13:18:38 +02:00

mutex.h

mutex: Use p->on_cpu for the adaptive spin

2011-04-14 08:52:33 +02:00

notifier.c

sched: Use lockdep-based checking on rcu_dereference()

2010-02-25 10:34:26 +01:00

ns_cgroup.c

cgroup: notify ns_cgroup deprecated

2010-10-27 18:03:09 -07:00

nsproxy.c

userns: user namespaces: convert several capable() calls

2011-03-23 19:47:08 -07:00

padata.c

Fix common misspellings

2011-03-31 11:26:23 -03:00

panic.c

move x86 specific oops=panic to generic code

2011-03-22 17:44:11 -07:00

params.c

Fix common misspellings

2011-03-31 11:26:23 -03:00

perf_event.c

perf_event: Fix cgrp event scheduling bug in perf_enable_on_exec()

2011-04-11 11:07:55 +02:00

pid_namespace.c

pidns: call pid_ns_prepare_proc() from create_pid_namespace()

2011-03-23 19:46:58 -07:00

pid.c

next_pidmap: fix overflow condition

2011-04-18 10:35:30 -07:00

pm_qos_params.c

PM QoS: Make pm_qos settings readable

2011-03-15 00:43:18 +01:00

posix-cpu-timers.c

Fix common misspellings

2011-03-31 11:26:23 -03:00

posix-timers.c

Fix common misspellings

2011-03-31 11:26:23 -03:00

printk.c

printk: allow setting DEFAULT_MESSAGE_LEVEL via Kconfig

2011-03-22 17:44:13 -07:00

profile.c

llseek: automatically add .llseek fop

2010-10-15 15:53:27 +02:00

ptrace.c

ptrace: Prepare to fix racy accesses on task breakpoints

2011-04-25 17:28:24 +02:00

range.c

kernel/range.c: fix clean_sort_range() for the case of full array

2010-11-12 07:55:31 -08:00

rcupdate.c

rcu: add comment saying why DEBUG_OBJECTS_RCU_HEAD depends on PREEMPT.

2011-03-04 08:05:41 -08:00

rcutiny_plugin.h

rcu: call __rcu_read_unlock() in exit_rcu for tiny RCU

2011-03-04 08:05:08 -08:00

rcutiny.c

rcu: avoid pointless blocked-task warnings

2011-01-14 04:58:08 -08:00

rcutorture.c

rcutorture: Get rid of duplicate sched.h include

2011-03-04 08:05:17 -08:00

rcutree_plugin.h

rcu: increase synchronize_sched_expedited() batching

2010-12-17 12:34:08 -08:00

rcutree_trace.c

rcu,cleanup: simplify the code when cpu is dying

2010-11-29 22:01:58 -08:00

rcutree.c

Merge branch 'for-2.6.38' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu

2011-01-07 17:02:58 -08:00

rcutree.h

rcu: limit rcu_node leaf-level fanout

2010-12-17 12:34:20 -08:00

relay.c

Clean up relay_alloc_page_array() slightly by using vzalloc rather than vmalloc and memset

2010-11-05 08:21:34 -07:00

res_counter.c

memcg: res_counter_read_u64(): fix potential races on 32-bit machines

2011-03-23 19:46:22 -07:00

resource.c

resources: add arch hook for preventing allocation in reserved areas

2010-12-17 10:01:09 -08:00

rtmutex_common.h

rtmutex: Simplify PI algorithm and make highest prio task get lock

2011-01-27 21:13:51 -05:00

rtmutex-debug.c

rtmutex: Simplify PI algorithm and make highest prio task get lock

2011-01-27 21:13:51 -05:00

rtmutex-debug.h

…

rtmutex-tester.c

rtmutex: tester: Remove the remaining BKL leftovers

2011-02-22 22:07:22 +01:00

rtmutex.c

rtmutex: Simplify PI algorithm and make highest prio task get lock

2011-01-27 21:13:51 -05:00

rtmutex.h

…

rwsem.c

…

sched_autogroup.c

Fix common misspellings

2011-03-31 11:26:23 -03:00

sched_autogroup.h

sched, autogroup: Stop going ahead if autogroup is disabled

2011-02-23 11:33:59 +01:00

sched_clock.c

sched: Add some clock info to sched_debug

2010-11-23 10:29:08 +01:00

sched_cpupri.c

sched: No need for bootmem special cases

2010-07-17 12:06:22 +02:00

sched_cpupri.h

sched: No need for bootmem special cases

2010-07-17 12:06:22 +02:00

sched_debug.c

sched: Get rid of lock_depth

2011-04-24 13:18:38 +02:00

sched_fair.c

sched: Remove unused 'this_best_prio arg' from balance_tasks()

2011-05-04 09:07:21 +02:00

sched_features.h

sched: Move the second half of ttwu() to the remote cpu

2011-04-14 08:52:41 +02:00

sched_idletask.c

sched: Drop the rq argument to sched_class::select_task_rq()

2011-04-14 08:52:36 +02:00

sched_rt.c

sched, rt: Update rq clock when unthrottling of an otherwise idle CPU

2011-05-16 11:01:17 +02:00

sched_stats.h

sched_stat: Update sched_info_queue/dequeue() code comments

2010-10-24 13:29:01 +02:00

sched_stoptask.c

sched: Drop the rq argument to sched_class::select_task_rq()

2011-04-14 08:52:36 +02:00

sched.c

sched: Fix and optimise calculation of the weight-inverse

2011-05-16 11:01:18 +02:00

seccomp.c

…

semaphore.c

…

signal.c

signal.c: fix erroneous syscall kernel-doc

2011-04-08 11:05:24 -07:00

smp.c

smp: move smp setup functions to kernel/smp.c

2011-03-22 17:44:11 -07:00

softirq.c

Fix common misspellings

2011-03-31 11:26:23 -03:00

spinlock.c

locking: Cleanup the name space completely

2009-12-14 23:55:33 +01:00

srcu.c

rcu: demote SRCU_SYNCHRONIZE_DELAY from kernel-parameter status

2011-01-14 04:56:49 -08:00

stacktrace.c

…

stop_machine.c

kthread: use kthread_create_on_node()

2011-03-22 17:44:01 -07:00

sys_ni.c

vfs: Add open by file handle support

2011-03-15 02:21:44 -04:00

sys.c

userns: user namespaces: convert all capable checks in kernel/sys.c

2011-03-23 19:47:06 -07:00

sysctl_binary.c

open-style analog of vfs_path_lookup()

2011-03-14 09:15:28 -04:00

sysctl_check.c

sysctl_check: drop dead code

2011-03-23 19:46:51 -07:00

sysctl.c

sysctl: restrict write access to dmesg_restrict

2011-03-23 19:46:54 -07:00

taskstats.c

taskstats: use appropriate printk priority level

2011-03-23 19:47:14 -07:00

test_kprobes.c

kprobes: Fix selftest to clear flags field for reusing probes

2010-10-14 08:55:27 +02:00

time.c

Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

2011-03-15 18:53:35 -07:00

timeconst.pl

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timer.c

Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

2011-03-15 18:53:35 -07:00

tracepoint.c

tracepoints: Fix section alignment using pointer array

2011-02-03 09:28:46 -05:00

tsacct.c

taskstats: use real microsecond granularity for CPU times

2010-10-27 18:03:17 -07:00

uid16.c

userns: user namespaces: convert several capable() calls

2011-03-23 19:47:08 -07:00

up.c

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user_namespace.c

user_ns: improve the user_ns on-the-slab packaging

2011-01-13 08:03:18 -08:00

user-return-notifier.c

Fix common misspellings

2011-03-31 11:26:23 -03:00

user.c

userns: add a user_namespace as creator/owner of uts_namespace

2011-03-23 19:46:59 -07:00

utsname_sysctl.c

…

utsname.c

userns: allow sethostname in a container

2011-03-23 19:47:03 -07:00

wait.c

Fix common misspellings

2011-03-31 11:26:23 -03:00

watchdog.c

kernel/watchdog.c: disable nmi perf event in the error path of enabling watchdog

2011-04-28 11:28:21 -07:00

workqueue_sched.h

workqueue: implement concurrency managed dynamic worker pool

2010-06-29 10:07:14 +02:00

workqueue.c

workqueue: fix deadlock in worker_maybe_bind_and_lock()

2011-04-29 18:08:37 +02:00