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2007-09-16timekeeping: access rtc outside of xtime lockThomas Gleixner
Lockdep complains about the access of rtc in timekeeping_suspend inside the interrupt disabled region of the write locked xtime lock. Move the access outside. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: John Stultz <johnstul@us.ibm.com>
2007-09-11Fix "no_sync_cmos_clock" logic inversion in kernel/time/ntp.cTony Breeds
Seems to me that this timer will only get started on platforms that say they don't want it? Signed-off-by: Tony Breeds <tony@bakeyournoodle.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Gabriel Paubert <paubert@iram.es> Cc: Zachary Amsden <zach@vmware.com> Acked-by: Thomas Gleixner <tglx@linutronix.de> Cc: John Stultz <johnstul@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-09-11Restore call_usermodehelper_pipe() behaviourMichael Ellerman
The semantics of call_usermodehelper_pipe() used to be that it would fork the helper, and wait for the kernel thread to be started. This was implemented by setting sub_info.wait to 0 (implicitly), and doing a wait_for_completion(). As part of the cleanup done in 0ab4dc92278a0f3816e486d6350c6652a72e06c8, call_usermodehelper_pipe() was changed to pass 1 as the value for wait to call_usermodehelper_exec(). This is equivalent to setting sub_info.wait to 1, which is a change from the previous behaviour. Using 1 instead of 0 causes __call_usermodehelper() to start the kernel thread running wait_for_helper(), rather than directly calling ____call_usermodehelper(). The end result is that the calling kernel code blocks until the user mode helper finishes. As the helper is expecting input on stdin, and now no one is writing anything, everything locks up (observed in do_coredump). The fix is to change the 1 to UMH_WAIT_EXEC (aka 0), indicating that we want to wait for the kernel thread to be started, but not for the helper to finish. Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Acked-by: Andi Kleen <ak@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-09-11futex_compat: fix list traversal bugsArnd Bergmann
The futex list traversal on the compat side appears to have a bug. It's loop termination condition compares: while (compat_ptr(uentry) != &head->list) But that can't be right because "uentry" has the special "pi" indicator bit still potentially set at bit 0. This is cleared by fetch_robust_entry() into the "entry" return value. What this seems to mean is that the list won't terminate when list iteration gets back to the the head. And we'll also process the list head like a normal entry, which could cause all kinds of problems. So we should check for equality with "entry". That pointer is of the non-compat type so we have to do a little casting to keep the compiler and sparse happy. The same problem can in theory occur with the 'pending' variable, although that has not been reported from users so far. Based on the original patch from David Miller. Acked-by: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: David Miller <davem@davemloft.net> Signed-off-by: Arnd Bergmann <arnd@arndb.de> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-09-10Fix spurious syscall tracing after PTRACE_DETACH + PTRACE_ATTACHRoland McGrath
When PTRACE_SYSCALL was used and then PTRACE_DETACH is used, the TIF_SYSCALL_TRACE flag is left set on the formerly-traced task. This means that when a new tracer comes along and does PTRACE_ATTACH, it's possible he gets a syscall tracing stop even though he's never used PTRACE_SYSCALL. This happens if the task was in the middle of a system call when the second PTRACE_ATTACH was done. The symptom is an unexpected SIGTRAP when the tracer thinks that only SIGSTOP should have been provoked by his ptrace calls so far. A few machines already fixed this in ptrace_disable (i386, ia64, m68k). But all other machines do not, and still have this bug. On x86_64, this constitutes a regression in IA32 compatibility support. Since all machines now use TIF_SYSCALL_TRACE for this, I put the clearing of TIF_SYSCALL_TRACE in the generic ptrace_detach code rather than adding it to every other machine's ptrace_disable. Signed-off-by: Roland McGrath <roland@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-09-05sched: fix ideal_runtime calculations for reniced tasksPeter Zijlstra
fix ideal_runtime: - do not scale it using niced_granularity() it is against sum_exec_delta, so its wall-time, not fair-time. - move the whole check into __check_preempt_curr_fair() so that wakeup preemption can also benefit from the new logic. this also results in code size reduction: text data bss dec hex filename 13391 228 1204 14823 39e7 sched.o.before 13369 228 1204 14801 39d1 sched.o.after Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2007-09-05sched: improve prev_sum_exec_runtime settingPeter Zijlstra
Second preparatory patch for fix-ideal runtime: Mark prev_sum_exec_runtime at the beginning of our run, the same spot that adds our wait period to wait_runtime. This seems a more natural location to do this, and it also reduces the code a bit: text data bss dec hex filename 13397 228 1204 14829 39ed sched.o.before 13391 228 1204 14823 39e7 sched.o.after Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2007-09-05sched: simplify __check_preempt_curr_fair()Peter Zijlstra
Preparatory patch for fix-ideal-runtime: simplify __check_preempt_curr_fair(): get rid of the integer return. text data bss dec hex filename 13404 228 1204 14836 39f4 sched.o.before 13393 228 1204 14825 39e9 sched.o.after functionality is unchanged. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2007-09-05sched: fix xtensa build warningIngo Molnar
rename RSR to SRR - 'RSR' is already defined on xtensa. found by Adrian Bunk. Signed-off-by: Ingo Molnar <mingo@elte.hu>
2007-09-05sched: debug: fix sum_exec_runtime clearingIngo Molnar
when cleaning sched-stats also clear prev_sum_exec_runtime. Signed-off-by: Ingo Molnar <mingo@elte.hu>
2007-09-05sched: debug: fix cfs_rq->wait_runtime accountingIngo Molnar
the cfs_rq->wait_runtime debug/statistics counter was not maintained properly - fix this. this also removes some code: text data bss dec hex filename 13420 228 1204 14852 3a04 sched.o.before 13404 228 1204 14836 39f4 sched.o.after Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
2007-09-05sched: fix niced_granularity() shiftIngo Molnar
fix niced_granularity(). This resulted in under-scheduling for CPU-bound negative nice level tasks (and this in turn caused higher than necessary latencies in nice-0 tasks). Signed-off-by: Ingo Molnar <mingo@elte.hu>
2007-09-05sched: fix MC/HT scheduler optimization, without breaking the FUZZ logic.Suresh Siddha
First fix the check if (*imbalance + SCHED_LOAD_SCALE_FUZZ < busiest_load_per_task) with this if (*imbalance < busiest_load_per_task) As the current check is always false for nice 0 tasks (as SCHED_LOAD_SCALE_FUZZ is same as busiest_load_per_task for nice 0 tasks). With the above change, imbalance was getting reset to 0 in the corner case condition, making the FUZZ logic fail. Fix it by not corrupting the imbalance and change the imbalance, only when it finds that the HT/MC optimization is needed. Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2007-08-31Merge git://git.kernel.org/pub/scm/linux/kernel/git/mingo/linux-2.6-schedLinus Torvalds
* git://git.kernel.org/pub/scm/linux/kernel/git/mingo/linux-2.6-sched: sched: clean up task_new_fair() sched: small schedstat fix sched: fix wait_start_fair condition in update_stats_wait_end() sched: call update_curr() in task_tick_fair() sched: make the scheduler converge to the ideal latency sched: fix sleeper bonus limit
2007-08-31sigqueue_free: fix the race with collect_signal()Oleg Nesterov
Spotted by taoyue <yue.tao@windriver.com> and Jeremy Katz <jeremy.katz@windriver.com>. collect_signal: sigqueue_free: list_del_init(&first->list); if (!list_empty(&q->list)) { // not taken } q->flags &= ~SIGQUEUE_PREALLOC; __sigqueue_free(first); __sigqueue_free(q); Now, __sigqueue_free() is called twice on the same "struct sigqueue" with the obviously bad implications. In particular, this double free breaks the array_cache->avail logic, so the same sigqueue could be "allocated" twice, and the bug can manifest itself via the "impossible" BUG_ON(!SIGQUEUE_PREALLOC) in sigqueue_free/send_sigqueue. Hopefully this can explain these mysterious bug-reports, see http://marc.info/?t=118766926500003 http://marc.info/?t=118466273000005 Alexey Dobriyan reports this patch makes the difference for the testcase, but nobody has an access to the application which opened the problems originally. Also, this patch removes tasklist lock/unlock, ->siglock is enough. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: taoyue <yue.tao@windriver.com> Cc: Jeremy Katz <jeremy.katz@windriver.com> Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com> Cc: Alexey Dobriyan <adobriyan@sw.ru> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Roland McGrath <roland@redhat.com> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-08-31userns: don't leak root userAlexey Dobriyan
Signed-off-by: Alexey Dobriyan <adobriyan@sw.ru> Acked-by: Cedric Le Goater <clg@fr.ibm.com> Acked-by: Serge Hallyn <serue@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-08-31request_irq: fix DEBUG_SHIRQ handlingJarek Poplawski
Mariusz Kozlowski reported lockdep's warning: > ================================= > [ INFO: inconsistent lock state ] > 2.6.23-rc2-mm1 #7 > --------------------------------- > inconsistent {in-hardirq-W} -> {hardirq-on-W} usage. > ifconfig/5492 [HC0[0]:SC0[0]:HE1:SE1] takes: > (&tp->lock){+...}, at: [<de8706e0>] rtl8139_interrupt+0x27/0x46b [8139too] > {in-hardirq-W} state was registered at: > [<c0138eeb>] __lock_acquire+0x949/0x11ac > [<c01397e7>] lock_acquire+0x99/0xb2 > [<c0452ff3>] _spin_lock+0x35/0x42 > [<de8706e0>] rtl8139_interrupt+0x27/0x46b [8139too] > [<c0147a5d>] handle_IRQ_event+0x28/0x59 > [<c01493ca>] handle_level_irq+0xad/0x10b > [<c0105a13>] do_IRQ+0x93/0xd0 > [<c010441e>] common_interrupt+0x2e/0x34 ... > other info that might help us debug this: > 1 lock held by ifconfig/5492: > #0: (rtnl_mutex){--..}, at: [<c0451778>] mutex_lock+0x1c/0x1f > > stack backtrace: ... > [<c0452ff3>] _spin_lock+0x35/0x42 > [<de8706e0>] rtl8139_interrupt+0x27/0x46b [8139too] > [<c01480fd>] free_irq+0x11b/0x146 > [<de871d59>] rtl8139_close+0x8a/0x14a [8139too] > [<c03bde63>] dev_close+0x57/0x74 ... This shows that a driver's irq handler was running both in hard interrupt and process contexts with irqs enabled. The latter was done during free_irq() call and was possible only with CONFIG_DEBUG_SHIRQ enabled. This was fixed by another patch. But similar problem is possible with request_irq(): any locks taken from irq handler could be vulnerable - especially with soft interrupts. This patch fixes it by disabling local interrupts during handler's run. (It seems, disabling softirqs should be enough, but it needs more checking on possible races or other special cases). Reported-by: Mariusz Kozlowski <m.kozlowski@tuxland.pl> Signed-off-by: Jarek Poplawski <jarkao2@o2.pl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-08-31PM: Fix dependencies of CONFIG_SUSPEND and CONFIG_HIBERNATIONRafael J. Wysocki
Dependencies of CONFIG_SUSPEND and CONFIG_HIBERNATION introduced by commit 296699de6bdc717189a331ab6bbe90e05c94db06 "Introduce CONFIG_SUSPEND for suspend-to-Ram and standby" are incorrect, as they don't cover the facts that (1) not all architectures support suspend and (2) SMP hibernation is only possible on X86 and PPC64 (if CONFIG_PPC64_SWSUSP is set). Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-08-31setpgid(child) fails if the child was forked by sub-threadOleg Nesterov
Spotted by Marcin Kowalczyk <qrczak@knm.org.pl>. sys_setpgid(child) fails if the child was forked by sub-thread. Fix the "is it our child" check. The previous commit ee0acf90d320c29916ba8c5c1b2e908d81f5057d was not complete. (this patch asks for the new same_thread_group() helper, but mainline doesn't have it yet). Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Acked-by: Roland McGrath <roland@redhat.com> Cc: <stable@kernel.org> Tested-by: "Marcin 'Qrczak' Kowalczyk" <qrczak@knm.org.pl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-08-31Assign task_struct.exit_code before taskstats_exit()Jonathan Lim
taskstats.ac_exitcode is assigned to task_struct.exit_code in bacct_add_tsk() through the following kernel function calls: do_exit() taskstats_exit() fill_pid() bacct_add_tsk() The problem is that in do_exit(), task_struct.exit_code is set to 'code' only after taskstats_exit() has been called. So we need to move the assignment before taskstats_exit(). Signed-off-by: Jonathan Lim <jlim@sgi.com> Cc: Balbir Singh <balbir@in.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-08-28sched: clean up task_new_fair()Ingo Molnar
cleanup: we have the 'se' and 'curr' entity-pointers already, no need to use p->se and current->se. Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Mike Galbraith <efault@gmx.de>
2007-08-28sched: small schedstat fixIngo Molnar
small schedstat fix: the cfs_rq->wait_runtime 'sum of all runtimes' statistics counters missed newly forked tasks and thus had a constant negative skew. Fix this. Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Mike Galbraith <efault@gmx.de>
2007-08-28sched: fix wait_start_fair condition in update_stats_wait_end()Ingo Molnar
Peter Zijlstra noticed the following bug in SCHED_FEAT_SKIP_INITIAL (which is disabled by default at the moment): it relies on se.wait_start_fair being 0 while update_stats_wait_end() did not recognize a 0 value, so instead of 'skipping' the initial interval we gave the new child a maximum boost of +runtime-limit ... (No impact on the default kernel, but nice to fix for completeness.) Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Mike Galbraith <efault@gmx.de>
2007-08-28sched: call update_curr() in task_tick_fair()Ting Yang
update the fair-clock before using it for the key value. [ mingo@elte.hu: small cleanups. ] Signed-off-by: Ting Yang <tingy@cs.umass.edu> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Mike Galbraith <efault@gmx.de> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
2007-08-28sched: make the scheduler converge to the ideal latencyIngo Molnar
de-HZ-ification of the granularity defaults unearthed a pre-existing property of CFS: while it correctly converges to the granularity goal, it does not prevent run-time fluctuations in the range of [-gran ... 0 ... +gran]. With the increase of the granularity due to the removal of HZ dependencies, this becomes visible in chew-max output (with 5 tasks running): out: 28 . 27. 32 | flu: 0 . 0 | ran: 9 . 13 | per: 37 . 40 out: 27 . 27. 32 | flu: 0 . 0 | ran: 17 . 13 | per: 44 . 40 out: 27 . 27. 32 | flu: 0 . 0 | ran: 9 . 13 | per: 36 . 40 out: 29 . 27. 32 | flu: 2 . 0 | ran: 17 . 13 | per: 46 . 40 out: 28 . 27. 32 | flu: 0 . 0 | ran: 9 . 13 | per: 37 . 40 out: 29 . 27. 32 | flu: 0 . 0 | ran: 18 . 13 | per: 47 . 40 out: 28 . 27. 32 | flu: 0 . 0 | ran: 9 . 13 | per: 37 . 40 average slice is the ideal 13 msecs and the period is picture-perfect 40 msecs. But the 'ran' field fluctuates around 13.33 msecs and there's no mechanism in CFS to keep that from happening: it's a perfectly valid solution that CFS finds. to fix this we add a granularity/preemption rule that knows about the "target latency", which makes tasks that run longer than the ideal latency run a bit less. The simplest approach is to simply decrease the preemption granularity when a task overruns its ideal latency. For this we have to track how much the task executed since its last preemption. ( this adds a new field to task_struct, but we can eliminate that overhead in 2.6.24 by putting all the scheduler timestamps into an anonymous union. ) with this change in place, chew-max output is fluctuation-less all around: out: 28 . 27. 39 | flu: 0 . 2 | ran: 13 . 13 | per: 41 . 40 out: 28 . 27. 39 | flu: 0 . 2 | ran: 13 . 13 | per: 41 . 40 out: 28 . 27. 39 | flu: 0 . 2 | ran: 13 . 13 | per: 41 . 40 out: 28 . 27. 39 | flu: 0 . 2 | ran: 13 . 13 | per: 41 . 40 out: 28 . 27. 39 | flu: 0 . 1 | ran: 13 . 13 | per: 41 . 40 out: 28 . 27. 39 | flu: 0 . 1 | ran: 13 . 13 | per: 41 . 40 this patch has no impact on any fastpath or on any globally observable scheduling property. (unless you have sharp enough eyes to see millisecond-level ruckles in glxgears smoothness :-) Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Mike Galbraith <efault@gmx.de>
2007-08-28sched: fix sleeper bonus limitMike Galbraith
There is an Amarok song switch time increase (regression) under hefty load. What is happening is that sleeper_bonus is never consumed, and only rarely goes below runtime_limit, so for the most part, Amarok isn't getting any bonus at all. We're keeping sleeper_bonus right at runtime_limit (sched_latency == sched_runtime_limit == 40ms) forever, ie we don't consume if we're lower that that, and don't add if we're above it. One Amarok thread waking (or anybody else) will push us past the threshold, so the next thread waking gets nada, but will reap pain from the previous thread waking until we drop back to runtime_limit. It looks to me like under load, some random task gets a bonus, and everybody else pays, whether deserving or not. This diff fixed the regression for me at any load rate. Signed-off-by: Mike Galbraith <efault@gmx.de> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
2007-08-27fix bogus hotplug cpu warningHugh Dickins
Fix bogus DEBUG_PREEMPT warning on x86_64, when cpu brought online after bootup: current_is_keventd is right to note its use of smp_processor_id is preempt-safe, but should use raw_smp_processor_id to avoid the warning. Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-08-25sched: s/sched_latency/sched_min_granularityIngo Molnar
runtime limit and wakeup granularity used to be a function of granularity and that was incorrect changed to sched_latency. Fix this to make wakeup granularity a function of min-granularity, and the runtime limit equal to latency. Signed-off-by: Ingo Molnar <mingo@elte.hu>
2007-08-25sched: cleanup, sched_granularity -> sched_min_granularityIngo Molnar
due to adaptive granularity scheduling the role of sched_granularity has changed to "minimum granularity", so rename the variable (and the tunable) accordingly. Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
2007-08-25sched: adaptive scheduler granularityPeter Zijlstra
Instead of specifying the preemption granularity, specify the wanted latency. By fixing the granlarity to a constany the wakeup latency it a function of the number of running tasks on the rq. Invert this relation. sysctl_sched_granularity becomes a minimum for the dynamic granularity computed from the new sysctl_sched_latency. Then use this latency to do more intelligent granularity decisions: if there are fewer tasks running then we can schedule coarser. This helps performance while still always keeping the latency target. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2007-08-25sched: fix CONFIG_SCHED_DEBUG dependency of lockdep sysctlsPeter Zijlstra
Make the lockdep sysctls not depend on CONFIG_SCHED_DEBUG. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2007-08-24sched: fix startup penalty calculationIngo Molnar
fix task startup penalty miscalculation: sysctl_sched_granularity is unsigned int and wait_runtime is long so we first have to convert it to long before turning it negative ... Signed-off-by: Ingo Molnar <mingo@elte.hu>
2007-08-24sched: simplify bonus calculation #2Peter Zijlstra
current code: delta = calc_delta_mine(delta_exec, curr->load.weight, lw); delta = min((u64)delta, cfs_rq->sleeper_bonus); Notice that this calc_delta_mine() line is exactly delta_mine, which gives: delta = min((u64)delta_mine, cfs_rq->sleeper_bonus); Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2007-08-24sched: simplify bonus calculation #1Peter Zijlstra
current code: delta = min(cfs_rq->sleeper_bonus, (u64)delta_exec); delta = calc_delta_mine(delta, curr->load.weight, lw); delta = min((u64)delta, cfs_rq->sleeper_bonus); drop the first min(), because we clip against sleeper_bonus in the 3rd line again. That gives: delta = calc_delta_mine(delta_exec, curr->load.weight, lw); delta = min((u64)delta, cfs_rq->sleeper_bonus); Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2007-08-24sched: tidy up and simplify the bonus balanceIngo Molnar
make the bonus balance more consistent: do not hand out a bonus if there's too much in flight already, and only deduct as much from a runner as it has the capacity. This makes the bonus engine a zero-sum game (as intended). this also simplifies the code: text data bss dec hex filename 34770 2998 24 37792 93a0 sched.o.before 34749 2998 24 37771 938b sched.o.after and it also avoids overscheduling in sleep-happy workloads like hackbench.c. Signed-off-by: Ingo Molnar <mingo@elte.hu>
2007-08-24sched: optimize task_tick_rt() a bitDmitry Adamushko
Mitchell Erblich suggested a quality-of-implementation change to not requeue SCHED_RR tasks if there's only a single task on the runqueue, by checking for rq->nr_running == 1. provide a more efficient implementation of that, to check that particular RT priority-queue only. [ From: mingo@elte.hu ] Also first requeue the task then set need_resched - results in slightly better machine-instruction ordering. Also clean up the code a bit. Signed-off-by: Dmitry Adamushko <dmitry.adamushko@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2007-08-24sched: simplify can_migrate_task()Sven-Thorsten Dietrich
Remove trivial conditional branch in Linux scheduler's can_migrate_task() function. text data bss dec hex filename 34770 2998 24 37792 93a0 sched.o.before 34757 2998 24 37779 9393 sched.o.after Signed-off-by: Sven-Thorsten Dietrich <sven@thebigcorporation.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2007-08-24sched: remove HZ dependency from the granularity defaultIngo Molnar
remove HZ dependency from the granularity default. Use 10 msec for the base granularity, 1 msec for wakeup granularity and 25 msec for batch wakeup granularity. (These defaults are close to the values that the default HZ=250 setting got previously, and thus it's the most common setting.) Signed-off-by: Ingo Molnar <mingo@elte.hu>
2007-08-24sched: CONFIG_SCHED_GROUP_FAIR=y fixletBruce Ashfield
when I built with CONFIG_FAIR_GROUP_SCHED=y, I need the following change to make things right. [ From: mingo@elte.hu ] this config option is not upstream-configurable right now but lets fix this for completeness. Signed-off-by: Bruce Ashfield <bruce.ashfield@windriver.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2007-08-23Merge git://git.kernel.org/pub/scm/linux/kernel/git/mingo/linux-2.6-schedLinus Torvalds
* git://git.kernel.org/pub/scm/linux/kernel/git/mingo/linux-2.6-sched: sched: tweak the sched_runtime_limit tunable sched: skip updating rq's next_balance under null SD sched: fix broken SMT/MC optimizations sched: accounting regression since rc1 sched: fix sysctl directory permissions sched: sched_clock_idle_[sleep|wakeup]_event()
2007-08-23Merge master.kernel.org:/pub/scm/linux/kernel/git/gregkh/driver-2.6Linus Torvalds
* master.kernel.org:/pub/scm/linux/kernel/git/gregkh/driver-2.6: sysfs: don't warn on removal of a nonexistent binary file HOWTO: latest lxr url address changed HOWTO: korean translation of Documentation/HOWTO Fix Off-by-one in /sys/module/*/refcnt sysfs: fix locking in sysfs_lookup() and sysfs_rename_dir()
2007-08-23sched: tweak the sched_runtime_limit tunableIngo Molnar
Michael Gerdau reported reniced task CPU usage weirdnesses. Such symptoms can be caused by limit underruns so double the sched_runtime_limit. Signed-off-by: Ingo Molnar <mingo@elte.hu>
2007-08-23sched: skip updating rq's next_balance under null SDSuresh Siddha
Was playing with sched_smt_power_savings/sched_mc_power_savings and found out that while the scheduler domains are reconstructed when sysfs settings change, rebalance_domains() can get triggered with null domain on other cpus, which is setting next_balance to jiffies + 60*HZ. Resulting in no idle/busy balancing for 60 seconds. Fix this. Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2007-08-23sched: fix broken SMT/MC optimizationsSuresh Siddha
On a four package system with HT - HT load balancing optimizations were broken. For example, if two tasks end up running on two logical threads of one of the packages, scheduler is not able to pull one of the tasks to a completely idle package. In this scenario, for nice-0 tasks, imbalance calculated by scheduler will be 512 and find_busiest_queue() will return 0 (as each cpu's load is 1024 > imbalance and has only one task running). Similarly MC scheduler optimizations also get fixed with this patch. [ mingo@elte.hu: restored fair balancing by increasing the fuzz and adding it back to the power decision, without the /2 factor. ] Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2007-08-23sched: fix sysctl directory permissionsEric W. Biederman
There are two remaining gotchas: - The directories have impossible permissions (writeable). - The ctl_name for the kernel directory is inconsistent with everything else. It should be CTL_KERN. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2007-08-23sched: sched_clock_idle_[sleep|wakeup]_event()Ingo Molnar
construct a more or less wall-clock time out of sched_clock(), by using ACPI-idle's existing knowledge about how much time we spent idling. This allows the rq clock to work around TSC-stops-in-C2, TSC-gets-corrupted-in-C3 type of problems. ( Besides the scheduler's statistics this also benefits blktrace and printk-timestamps as well. ) Furthermore, the precise before-C2/C3-sleep and after-C2/C3-wakeup callbacks allow the scheduler to get out the most of the period where the CPU has a reliable TSC. This results in slightly more precise task statistics. the ACPI bits were acked by Len. Signed-off-by: Ingo Molnar <mingo@elte.hu> Acked-by: Len Brown <len.brown@intel.com>
2007-08-22signalfd: fix interaction with posix-timersOleg Nesterov
dequeue_signal: if (__SI_TIMER) { spin_unlock(&tsk->sighand->siglock); do_schedule_next_timer(info); spin_lock(&tsk->sighand->siglock); } Unless tsk == curent, this is absolutely unsafe: nothing prevents tsk from exiting. If signalfd was passed to another process, do_schedule_next_timer() is just wrong. Add yet another "tsk == current" check into dequeue_signal(). This patch fixes an oopsable bug, but breaks the scheduling of posix timers if the shared __SI_TIMER signal was fetched via signalfd attached to another sub-thread. Mostly fixed by the next patch. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Davide Libenzi <davidel@xmailserver.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Michael Kerrisk <mtk-manpages@gmx.net> Cc: Roland McGrath <roland@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-08-22posix-timers: fix creation raceOleg Nesterov
sys_timer_create() sets ->it_process and unlocks ->siglock, then checks tmr->it_sigev_notify to define if get_task_struct() is needed. We already passed ->it_id to the caller, another thread can delete this timer and free its memory in between. As a minimal fix, move this code under ->siglock, sys_timer_delete() takes it too before calling release_posix_timer(). A proper serialization would be to take ->it_lock, we add a partly initialized timer on posix_timers_id, not good. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-08-22posix-timers: fix deletion raceThomas Gleixner
timer_delete does: lock_timer(); timer->it_process = NULL; unlock_timer(); release_posix_timer(); timer->it_process is checked in lock_timer() to prevent access to a timer, which is on the way to be deleted, but the check happens after idr_lock is dropped. This allows release_posix_timer() to delete the timer before the lock code can check the timer: CPU 0 CPU 1 lock_timer(); timer->it_process = NULL; unlock_timer(); lock_timer() spin_lock(idr_lock); timer = idr_find(); spin_lock(timer->lock); spin_unlock(idr_lock); release_posix_timer(); spin_lock(idr_lock); idr_remove(timer); spin_unlock(idr_lock); free_timer(timer); if (timer->......) Change the locking to prevent this. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-08-22free_irq(): fix DEBUG_SHIRQ handlingAndrew Morton
If we're going to run the handler from free_irq() then we must do it with local irq's disabled. Otherwise lockdep complains that the handler is taking irq-safe spinlocks in a non-irq-safe fashion. Cc: Ingo Molnar <mingo@elte.hu> Cc: David Woodhouse <dwmw2@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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