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* sched: disable source/target_load biasPeter Zijlstra2008-06-272-2/+3
| | | | | | | | | | The bias given by source/target_load functions can be very large, disable it by default to get faster convergence. Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> Cc: Mike Galbraith <efault@gmx.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: optimize effective_load()Peter Zijlstra2008-06-271-4/+4
| | | | | | | | | | | | | | | | | | | | | | s_i = S * rw_i / \Sum_j rw_j -> \Sum_j rw_j = S * rw_i / s_i -> s'_i = S * (rw_i + w) / (\Sum_j rw_j + w) delta s = s' - s = S * (rw + w) / ((S * rw / s) + w) = s * (S * (rw + w) / (S * rw + s * w) - 1) a = S*(rw+w), b = S*rw + s*w delta s = s * (a-b) / b IOW, trade one divide for two multiplies Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> Cc: Mike Galbraith <efault@gmx.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: remove prio preference from balance decisionsPeter Zijlstra2008-06-271-9/+3Star
| | | | | | | | | | Priority looses much of its meaning in a hierarchical context. So don't use it in balance decisions. Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> Cc: Mike Galbraith <efault@gmx.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: fix task_h_load()Peter Zijlstra2008-06-271-9/+40
| | | | | | | | | | | | | | | | | | | | | | | | | Currently task_h_load() computes the load of a task and uses that to either subtract it from the total, or add to it. However, removing or adding a task need not have any effect on the total load at all. Imagine adding a task to a group that is local to one cpu - in that case the total load of that cpu is unaffected. So properly compute addition/removal: s_i = S * rw_i / \Sum_j rw_j s'_i = S * (rw_i + wl) / (\Sum_j rw_j + wg) then s'_i - s_i gives the change in load. Where s_i is the shares for cpu i, S the group weight, rw_i the runqueue weight for that cpu, wl the weight we add (subtract) and wg the weight contribution to the runqueue. Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> Cc: Mike Galbraith <efault@gmx.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: fix load scaling in group balancingPeter Zijlstra2008-06-271-4/+6
| | | | | | | | | | | | | | doing the load balance will change cfs_rq->load.weight (that's the whole point) but since that's part of the scale factor, we'll scale back with a different amount. Weight getting smaller would result in an inflated moved_load which causes it to stop balancing too soon. Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> Cc: Mike Galbraith <efault@gmx.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: hierarchical load vs find_busiest_groupPeter Zijlstra2008-06-271-3/+23
| | | | | | | | | | | find_busiest_group() has some assumptions about task weight being in the NICE_0_LOAD range. Hierarchical task groups break this assumption - fix this by replacing it with the average task weight, which will adapt the situation. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> Cc: Mike Galbraith <efault@gmx.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: hierarchical load vs affine wakeupsPeter Zijlstra2008-06-271-2/+21
| | | | | | | | | | With hierarchical grouping we can't just compare task weight to rq weight - we need to scale the weight appropriately. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> Cc: Mike Galbraith <efault@gmx.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: persistent average load per taskPeter Zijlstra2008-06-271-13/+12Star
| | | | | | | | | | | Remove the fall-back to SCHED_LOAD_SCALE by remembering the previous value of cpu_avg_load_per_task() - this is useful because of the hierarchical group model in which task weight can be much smaller. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> Cc: Mike Galbraith <efault@gmx.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: fix sched_balance_self() smp group balancingPeter Zijlstra2008-06-271-0/+3
| | | | | | | | | Finding the least idle cpu is more accurate when done with updated shares. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> Cc: Mike Galbraith <efault@gmx.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: fix newidle smp group balancingPeter Zijlstra2008-06-271-0/+13
| | | | | | | | | | Re-compute the shares on newidle - so we can make a decision based on recent data. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> Cc: Mike Galbraith <efault@gmx.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: simplify the group load balancerPeter Zijlstra2008-06-272-229/+72Star
| | | | | | | | | | | | | | | | | | | | | While thinking about the previous patch - I realized that using per domain aggregate load values in load_balance_fair() is wrong. We should use the load value for that CPU. By not needing per domain hierarchical load values we don't need to store per domain aggregate shares, which greatly simplifies all the math. It basically falls apart in two separate computations: - per domain update of the shares - per CPU update of the hierarchical load Also get rid of the move_group_shares() stuff - just re-compute the shares again after a successful load balance. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> Cc: Mike Galbraith <efault@gmx.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: no need to aggregate task_weightPeter Zijlstra2008-06-272-16/+2Star
| | | | | | | | | | We only need to know the task_weight of the busiest rq - nothing to do if there are no tasks there. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> Cc: Mike Galbraith <efault@gmx.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: dont micro manage share lossesPeter Zijlstra2008-06-271-23/+3Star
| | | | | | | | | | | We used to try and contain the loss of 'shares' by playing arithmetic games. Replace that by noticing that at the top sched_domain we'll always have the full weight in shares to distribute. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> Cc: Mike Galbraith <efault@gmx.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: kill task_group balancingSrivatsa Vaddagiri2008-06-271-13/+2Star
| | | | | | | | | | | | | | | The idea was to balance groups until we've reached the global goal, however Vatsa rightly pointed out that we might never reach that goal this way - hence take out this logic. [ the initial rationale for this 'feature' was to promote max concurrency within a group - it does not however affect fairness ] Reported-by: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> Cc: Mike Galbraith <efault@gmx.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: update aggregate when holding the RQsPeter Zijlstra2008-06-271-0/+20
| | | | | | | | | | | | | | | | It was observed that in __update_group_shares_cpu() rq_weight > aggregate()->rq_weight This is caused by forks/wakeups in between the initial aggregate pass and locking of the RQs for load balance. To avoid this situation partially re-do the aggregation once we have the RQs locked (which avoids new tasks from appearing). Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> Cc: Mike Galbraith <efault@gmx.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: fix sched_domain aggregationPeter Zijlstra2008-06-272-65/+60Star
| | | | | | | | | | | Keeping the aggregate on the first cpu of the sched domain has two problems: - it could collide between different sched domains on different cpus - it could slow things down because of the remote accesses Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> Cc: Mike Galbraith <efault@gmx.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: add full schedstats to /proc/sched_debugPeter Zijlstra2008-06-271-2/+17
| | | | | | | | | show all the schedstats in /debug/sched_debug as well. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> Cc: Mike Galbraith <efault@gmx.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: fix wakeup granularity and buddy granularityPeter Zijlstra2008-06-272-8/+8
| | | | | | | | | | | | | | Uncouple buddy selection from wakeup granularity. The initial idea was that buddies could run ahead as far as a normal task can - do this by measuring a pair 'slice' just as we do for a normal task. This means we can drop the wakeup_granularity back to 5ms. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> Cc: Mike Galbraith <efault@gmx.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: sched_clock_cpu() based cpu_clock()Peter Zijlstra2008-06-272-76/+12Star
| | | | | | | | | | with sched_clock_cpu() being reasonably in sync between cpus (max 1 jiffy difference) use this to provide cpu_clock(). Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> Cc: Mike Galbraith <efault@gmx.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: revert revert of: fair-group: SMP-nice for group schedulingPeter Zijlstra2008-06-274-75/+488
| | | | | | | | | | | | Try again.. Initial commit: 18d95a2832c1392a2d63227a7a6d433cb9f2037e Revert: 6363ca57c76b7b83639ca8c83fc285fa26a7880e Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> Cc: Mike Galbraith <efault@gmx.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: fix calc_delta_asym, #2Peter Zijlstra2008-06-271-3/+6
| | | | | | | | | | | | | | | | | Ok, so why are we in this mess, it was: 1/w but now we mixed that rw in the mix like: rw/w rw being \Sum w suggests: fiddling w, we should also fiddle rw, humm? Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> Cc: Mike Galbraith <efault@gmx.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: fix calc_delta_asym()Peter Zijlstra2008-06-272-1/+28
| | | | | | | | | | | | | | | | | | | calc_delta_asym() is supposed to do the same as calc_delta_fair() except linearly shrink the result for negative nice processes - this causes them to have a smaller preemption threshold so that they are more easily preempted. The problem is that for task groups se->load.weight is the per cpu share of the actual task group weight; take that into account. Also provide a debug switch to disable the asymmetry (which I still don't like - but it does greatly benefit some workloads) This would explain the interactivity issues reported against group scheduling. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> Cc: Mike Galbraith <efault@gmx.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: revert the revert of: weight calculationsPeter Zijlstra2008-06-273-39/+76
| | | | | | | | | | | | Try again.. initial commit: 8f1bc385cfbab474db6c27b5af1e439614f3025c revert: f9305d4a0968201b2818dbed0dc8cb0d4ee7aeb3 Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> Cc: Mike Galbraith <efault@gmx.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: clean up some unused variablesPeter Zijlstra2008-06-271-2/+0Star
| | | | | | | | | | | | | In file included from /mnt/build/linux-2.6/kernel/sched.c:1496: /mnt/build/linux-2.6/kernel/sched_rt.c: In function '__enable_runtime': /mnt/build/linux-2.6/kernel/sched_rt.c:339: warning: unused variable 'rd' /mnt/build/linux-2.6/kernel/sched_rt.c: In function 'requeue_rt_entity': /mnt/build/linux-2.6/kernel/sched_rt.c:692: warning: unused variable 'queue' Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> Cc: Mike Galbraith <efault@gmx.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* Merge branch 'linus' into sched/develIngo Molnar2008-06-253-29/+81
|\ | | | | | | | | | | | | | | Conflicts: kernel/sched_rt.c Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * kgdb: sparse fixJason Wessel2008-06-241-1/+2
| | | | | | | | | | | | | | | | - Fix warning reported by sparse kernel/kgdb.c:1502:6: warning: symbol 'kgdb_console_write' was not declared. Should it be static? Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
| * Merge branch 'core-fixes-for-linus' of ↵Linus Torvalds2008-06-231-20/+73
| |\ | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: futexes: fix fault handling in futex_lock_pi
| | * futexes: fix fault handling in futex_lock_piThomas Gleixner2008-06-231-20/+73
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch addresses a very sporadic pi-futex related failure in highly threaded java apps on large SMP systems. David Holmes reported that the pi_state consistency check in lookup_pi_state triggered with his test application. This means that the kernel internal pi_state and the user space futex variable are out of sync. First we assumed that this is a user space data corruption, but deeper investigation revieled that the problem happend because the pi-futex code is not handling a fault in the futex_lock_pi path when the user space variable needs to be fixed up. The fault happens when a fork mapped the anon memory which contains the futex readonly for COW or the page got swapped out exactly between the unlock of the futex and the return of either the new futex owner or the task which was the expected owner but failed to acquire the kernel internal rtmutex. The current futex_lock_pi() code drops out with an inconsistent in case it faults and returns -EFAULT to user space. User space has no way to fixup that state. When we wrote this code we thought that we could not drop the hash bucket lock at this point to handle the fault. After analysing the code again it turned out to be wrong because there are only two tasks involved which might modify the pi_state and the user space variable: - the task which acquired the rtmutex - the pending owner of the pi_state which did not get the rtmutex Both tasks drop into the fixup_pi_state() function before returning to user space. The first task which acquired the hash bucket lock faults in the fixup of the user space variable, drops the spinlock and calls futex_handle_fault() to fault in the page. Now the second task could acquire the hash bucket lock and tries to fixup the user space variable as well. It either faults as well or it succeeds because the first task already faulted the page in. One caveat is to avoid a double fixup. After returning from the fault handling we reacquire the hash bucket lock and check whether the pi_state owner has been modified already. Reported-by: David Holmes <david.holmes@sun.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: David Holmes <david.holmes@sun.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: <stable@kernel.org> Signed-off-by: Ingo Molnar <mingo@elte.hu> kernel/futex.c | 93 ++++++++++++++++++++++++++++++++++++++++++++------------- 1 file changed, 73 insertions(+), 20 deletions(-)
| * | Merge branch 'linus' into sched/urgentIngo Molnar2008-06-234-10/+18
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| * | sched: refactor wait_for_completion_timeout()Oleg Nesterov2008-06-201-18/+6Star
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Simplify the code and fix the boundary condition of wait_for_completion_timeout(,0). We can kill the first __remove_wait_queue() as well. Signed-off-by: Ingo Molnar <mingo@elte.hu> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
| * | sched: fix wait_for_completion_timeout() spurious failure under heavy loadRoland Dreier2008-06-201-0/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | It seems that the current implementaton of wait_for_completion_timeout() has a small problem under very high load for the common pattern: if (!wait_for_completion_timeout(&done, timeout)) /* handle failure */ because the implementation very roughly does (lots of code deleted to show the basic flow): static inline long __sched do_wait_for_common(struct completion *x, long timeout, int state) { if (x->done) return timeout; do { timeout = schedule_timeout(timeout); if (!timeout) return timeout; } while (!x->done); return timeout; } so if the system is very busy and x->done is not set when do_wait_for_common() is entered, it is possible that the first call to schedule_timeout() returns 0 because the task doing wait_for_completion doesn't get rescheduled for a long time, even if it is woken up early enough. In this case, wait_for_completion_timeout() returns 0 without even checking x->done again, and the code above falls into its failure case purely for scheduler reasons, even if the hardware event or whatever was being waited for happened early enough. It would make sense to add an extra test to do_wait_for() in the timeout case and return 1 if x->done is actually set. A quick audit (not exhaustive) of wait_for_completion_timeout() callers seems to indicate that no one actually cares about the return value in the success case -- they just test for 0 (timed out) versus non-zero (wait succeeded). Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | sched: rt: dont stop the period timer when there are tasks wanting to runPeter Zijlstra2008-06-201-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | So if the group ever gets throttled, it will never wake up again. Reported-by: "Daniel K." <dk@uw.no> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Tested-by: Daniel K. <dk@uw.no> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | Merge branch 'linus' into sched/develIngo Molnar2008-06-235-10/+24
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| * | Merge branch 'core-fixes-for-linus' of ↵Linus Torvalds2008-06-204-10/+18
| |\ \ | | |/ | |/| | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: softlockup: fix NMI hangs due to lock race - 2.6.26-rc regression rcupreempt: remove export of rcu_batches_completed_bh cpuset: limit the input of cpuset.sched_relax_domain_level
| | * softlockup: fix NMI hangs due to lock race - 2.6.26-rc regressionJason Wessel2008-06-191-5/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The touch_nmi_watchdog() routine on x86 ultimately calls touch_softlockup_watchdog(). The problem is that to touch the softlockup watchdog, the cpu_clock code has to be called which could involve multiple cpu locks and can lead to a hard hang if one of the locks is held by a processor that is not going to return anytime soon (such as could be the case with kgdb or perhaps even with some other kind of exception). This patch causes the public version of the touch_softlockup_watchdog() to defer the cpu clock access to a later point. The test case for this problem is to use the following kernel config options: CONFIG_KGDB_TESTS=y CONFIG_KGDB_TESTS_ON_BOOT=y CONFIG_KGDB_TESTS_BOOT_STRING="V1F100I100000" It should be noted that kgdb test suite and these options were not available until 2.6.26-rc2, so it was necessary to patch the kgdb test suite during the bisection. I would consider this patch a regression fix because the problem first appeared in commit 27ec4407790d075c325e1f4da0a19c56953cce23 when some logic was added to try to periodically sync the clocks. It was possible to work around this particular problem by simply not performing the sync anytime the system was in a critical context. This was ok until commit 3e51f33fcc7f55e6df25d15b55ed10c8b4da84cd, which added config option CONFIG_HAVE_UNSTABLE_SCHED_CLOCK and some multi-cpu locks to sync the clocks. It became clear that accessing this code from an nmi was the source of the lockups. Avoiding the access to the low level clock code from an code inside the NMI processing also fixed the problem with the 27ec44... commit. Signed-off-by: Jason Wessel <jason.wessel@windriver.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| | * rcupreempt: remove export of rcu_batches_completed_bhSteven Rostedt2008-06-191-2/+0Star
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In rcupreempt, rcu_batches_completed_bh is defined as a static inline in the header file. This does not need to be exported, and not only that, this breaks my PPC build. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: paulus@samba.org Cc: linuxppc-dev@ozlabs.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| | * cpuset: limit the input of cpuset.sched_relax_domain_levelLi Zefan2008-06-192-3/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We allow the inputs to be [-1 ... SD_LV_MAX), and return -EINVAL for inputs outside this range. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: Paul Menage <menage@google.com> Acked-by: Paul Jackson <pj@sgi.com> Acked-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | sched, delay accounting: fix incorrect delay time when constantly waiting on ↵Bharath Ravi2008-06-191-0/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | runqueue This patch corrects the incorrect value of per process run-queue wait time reported by delay statistics. The anomaly was due to the following reason. When a process leaves the CPU and immediately starts waiting for CPU on the runqueue (which means it remains in the TASK_RUNNABLE state), the time of re-entry into the run-queue is never recorded. Due to this, the waiting time on the runqueue from this point of re-entry upto the next time it hits the CPU is not accounted for. This is solved by recording the time of re-entry of a process leaving the CPU in the sched_info_depart() function IF the process will go back to waiting on the run-queue. This IF condition is verified by checking whether the process is still in the TASK_RUNNABLE state. The patch was tested on 2.6.26-rc6 using two simple CPU hog programs. The values noted prior to the fix did not account for the time spent on the runqueue waiting. After the fix, the correct values were reported back to user space. Signed-off-by: Bharath Ravi <bharathravi1@gmail.com> Signed-off-by: Madhava K R <madhavakr@gmail.com> Cc: dhaval@linux.vnet.ibm.com Cc: vatsa@in.ibm.com Cc: balbir@in.ibm.com Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | sched: CPU hotplug events must not destroy scheduler domains created by the ↵Max Krasnyansky2008-06-192-0/+28
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | cpusets First issue is not related to the cpusets. We're simply leaking doms_cur. It's allocated in arch_init_sched_domains() which is called for every hotplug event. So we just keep reallocation doms_cur without freeing it. I introduced free_sched_domains() function that cleans things up. Second issue is that sched domains created by the cpusets are completely destroyed by the CPU hotplug events. For all CPU hotplug events scheduler attaches all CPUs to the NULL domain and then puts them all into the single domain thereby destroying domains created by the cpusets (partition_sched_domains). The solution is simple, when cpusets are enabled scheduler should not create default domain and instead let cpusets do that. Which is exactly what the patch does. Signed-off-by: Max Krasnyansky <maxk@qualcomm.com> Cc: pj@sgi.com Cc: menage@google.com Cc: rostedt@goodmis.org Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* | | sched: rt: dont stop the period timer when there are tasks wanting to runPeter Zijlstra2008-06-201-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | So if the group ever gets throttled, it will never wake up again. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: "Daniel K." <dk@uw.no> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Reported-by: "Daniel K." <dk@uw.no>
* | | sched: rt: fix the bandwidth contraint computationsPeter Zijlstra2008-06-201-3/+8
| | | | | | | | | | | | | | | | | | Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: "Daniel K." <dk@uw.no> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | sched: rt: move some code aroundPeter Zijlstra2008-06-201-62/+57Star
| | | | | | | | | | | | | | | | | | Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: "Daniel K." <dk@uw.no> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | sched: rt: fix SMP bandwidth balancing for throttled groupsPeter Zijlstra2008-06-201-12/+29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Now we exceed the runtime and get throttled - the period rollover tick will subtract the cpu quota from the runtime and check if we're below quota. However with this cpu having a very small portion of the runtime it will not refresh as fast as it should. Therefore, also rebalance the runtime when we're throttled. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: "Daniel K." <dk@uw.no> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | sched: debug: add some rt debug outputPeter Zijlstra2008-06-202-3/+51
| | | | | | | | | | | | | | | | | | Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: "Daniel K." <dk@uw.no> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | Merge branch 'sched' into sched-develIngo Molnar2008-06-192-30/+40
|\| | | | | | | | | | | | | | | | | | | | | | | Conflicts: kernel/sched_rt.c Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | sched: rt-group: fix RR bugletPeter Zijlstra2008-06-191-1/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In tick_task_rt() we first call update_curr_rt() which can dequeue a runqueue due to it running out of runtime, and then we try to requeue it, of it also having exhausted its RR quota. Obviously requeueing something that is no longer on the runqueue will not have the expected result. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Tested-by: Daniel K. <dk@uw.no> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | sched: rt-group: heirarchy aware throttlePeter Zijlstra2008-06-191-26/+33
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The bandwidth throttle code dequeues a group when it runs out of quota, and re-queues it once the period rolls over and the quota gets refreshed. Sadly it failed to take the hierarchy into consideration. Share more of the enqueue/dequeue code with regular task opterations. Also, some operations like sched_setscheduler() can dequeue/enqueue tasks that are in throttled runqueues, we should not inadvertly re-enqueue empty runqueues so check for that. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Tested-by: Daniel K. <dk@uw.no> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | sched: rt-group: fix hierarchyPeter Zijlstra2008-06-191-1/+0Star
| | | | | | | | | | | | | | | | | | | | | | | | | | | Don't re-set the entity's runqueue to the wrong rq after we've set it to the right one. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Tested-by: Daniel K. <dk@uw.no> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | sched: NULL pointer dereference while setting sched_rt_period_usDario Faggioli2008-06-191-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When CONFIG_RT_GROUP_SCHED and CONFIG_CGROUP_SCHED are enabled, with: echo 10000 > /proc/sys/kernel/sched_rt_period_us We get this: BUG: unable to handle kernel NULL pointer dereference at 0000008c [ 947.682233] IP: [<c0216b72>] __rt_schedulable+0x12/0x160 [ 947.683123] *pde = 00000000=20 [ 947.683782] Oops: 0000 [#1] [ 947.684307] Modules linked in: [ 947.684308] [ 947.684308] Pid: 2359, comm: bash Not tainted (2.6.26-rc6 #8) [ 947.684308] EIP: 0060:[<c0216b72>] EFLAGS: 00000246 CPU: 0 [ 947.684308] EIP is at __rt_schedulable+0x12/0x160 [ 947.684308] EAX: 00000000 EBX: 00000000 ECX: 00000000 EDX: 00000001 [ 947.684308] ESI: c0521db4 EDI: 00000001 EBP: c6cc9f00 ESP: c6cc9ed0 [ 947.684308] DS: 007b ES: 007b FS: 0000 GS: 0033 SS: 0068 [ 947.684308] Process bash (pid: 2359, tiÆcc8000 taskÇa54f00=20 task.tiÆcc8000) [ 947.684308] Stack: c0222790 00000000 080f8c08 c0521db4 c6cc9f00 00000001 00000000 00000000 [ 947.684308] c6cc9f9c 00000000 c0521db4 00000001 c6cc9f28 c0216d40 00000000 00000000 [ 947.684308] c6cc9f9c 000f4240 000e7ef0 ffffffff c0521db4 c79dfb60 c6cc9f58 c02af2cc [ 947.684308] Call Trace: [ 947.684308] [<c0222790>] ? do_proc_dointvec_conv+0x0/0x50 [ 947.684308] [<c0216d40>] ? sched_rt_handler+0x80/0x110 [ 947.684308] [<c02af2cc>] ? proc_sys_call_handler+0x9c/0xb0 [ 947.684308] [<c02af2fa>] ? proc_sys_write+0x1a/0x20 [ 947.684308] [<c0273c36>] ? vfs_write+0x96/0x160 [ 947.684308] [<c02af2e0>] ? proc_sys_write+0x0/0x20 [ 947.684308] [<c027423d>] ? sys_write+0x3d/0x70 [ 947.684308] [<c0202ef5>] ? sysenter_past_esp+0x6a/0x91 [ 947.684308] ======================= [ 947.684308] Code: 24 04 e8 62 b1 0e 00 89 c7 89 f8 8b 5d f4 8b 75 f8 8b 7d fc 89 ec 5d c3 90 55 89 e5 57 56 53 83 ec 24 89 45 ec 89 55 e4 89 4d e8 <8b> b8 8c 00 00 00 85 ff 0f 84 c9 00 00 00 8b 57 24 39 55 e8 8b [ 947.684308] EIP: [<c0216b72>] __rt_schedulable+0x12/0x160 SS:ESP 0068:c6cc9ed0 We think the following patch solves the issue. Signed-off-by: Dario Faggioli <raistlin@linux.it> Signed-off-by: Michael Trimarchi <trimarchimichael@yahoo.it> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | sched: fix defined-but-unused warningRabin Vincent2008-06-171-0/+2
| |/ | | | | | | | | | | | | | | | | | | Fix this warning, which appears with !CONFIG_SMP: kernel/sched.c:1216: warning: `init_hrtick' defined but not used Signed-off-by: Rabin Vincent <rabin@rab.in> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
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