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* sched: clean up schedule_balance_rt()Ingo Molnar2008-01-25
| | | | | | clean up schedule_balance_rt(). Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: clean up pull_rt_task()Ingo Molnar2008-01-25
| | | | | | clean up pull_rt_task(). Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: remove leftover debuggingIngo Molnar2008-01-25
| | | | | | remove leftover debugging. Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: remove rt_overload()Ingo Molnar2008-01-25
| | | | | | remove rt_overload() - it's an unnecessary indirection. Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: clean up kernel/sched_rt.cIngo Molnar2008-01-25
| | | | | | clean up whitespace damage and missing comments in kernel/sched_rt.c. Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: clean up overlong line in kernel/sched_debug.cIngo Molnar2008-01-25
| | | | | | clean up overlong line in kernel/sched_debug.c. Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: clean up find_lock_lowest_rq()Ingo Molnar2008-01-25
| | | | | | clean up find_lock_lowest_rq(). Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: clean up pick_next_highest_task_rt()Ingo Molnar2008-01-25
| | | | | | clean up pick_next_highest_task_rt(). Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: RT-balance on new taskSteven Rostedt2008-01-25
| | | | | | rt-balance when creating new tasks. Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: RT-balance, optimize cpu searchSteven Rostedt2008-01-25
| | | | | | | | | | | This patch removes several cpumask operations by keeping track of the first of the CPUS that is of the lowest priority. When the search for the lowest priority runqueue is completed, all the bits up to the first CPU with the lowest priority runqueue is cleared. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: RT-balance, optimizeGregory Haskins2008-01-25
| | | | | | | | | We can cheaply track the number of bits set in the cpumask for the lowest priority CPUs. Therefore, compute the mask's weight and use it to skip the optimal domain search logic when there is only one CPU available. Signed-off-by: Gregory Haskins <ghaskins@novell.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: break out early if RT task cannot be migratedGregory Haskins2008-01-25
| | | | | | | | We don't need to bother searching if the task cannot be migrated Signed-off-by: Gregory Haskins <ghaskins@novell.com> Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: RT-balance, avoid overloadingSteven Rostedt2008-01-25
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch changes the searching for a run queue by a waking RT task to try to pick another runqueue if the currently running task is an RT task. The reason is that RT tasks behave different than normal tasks. Preempting a normal task to run a RT task to keep its cache hot is fine, because the preempted non-RT task may wait on that same runqueue to run again unless the migration thread comes along and pulls it off. RT tasks behave differently. If one is preempted, it makes an active effort to continue to run. So by having a high priority task preempt a lower priority RT task, that lower RT task will then quickly try to run on another runqueue. This will cause that lower RT task to replace its nice hot cache (and TLB) with a completely cold one. This is for the hope that the new high priority RT task will keep its cache hot. Remeber that this high priority RT task was just woken up. So it may likely have been sleeping for several milliseconds, and will end up with a cold cache anyway. RT tasks run till they voluntarily stop, or are preempted by a higher priority task. This means that it is unlikely that the woken RT task will have a hot cache to wake up to. So pushing off a lower RT task is just killing its cache for no good reason. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: wake-balance fixesGregory Haskins2008-01-25
| | | | | | | | | | We have logic to detect whether the system has migratable tasks, but we are not using it when deciding whether to push tasks away. So we add support for considering this new information. Signed-off-by: Gregory Haskins <ghaskins@novell.com> Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: optimize RT affinityGregory Haskins2008-01-25
| | | | | | | | | | | | | | | | | The current code base assumes a relatively flat CPU/core topology and will route RT tasks to any CPU fairly equally. In the real world, there are various toplogies and affinities that govern where a task is best suited to run with the smallest amount of overhead. NUMA and multi-core CPUs are prime examples of topologies that can impact cache performance. Fortunately, linux is already structured to represent these topologies via the sched_domains interface. So we change our RT router to consult a combination of topology and affinity policy to best place tasks during migration. Signed-off-by: Gregory Haskins <ghaskins@novell.com> Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: pre-route RT tasks on wakeupGregory Haskins2008-01-25
| | | | | | | | | | | | | | | | | | | | | | | | | | In the original patch series that Steven Rostedt and I worked on together, we both took different approaches to low-priority wakeup path. I utilized "pre-routing" (push the task away to a less important RQ before activating) approach, while Steve utilized a "post-routing" approach. The advantage of my approach is that you avoid the overhead of a wasted activate/deactivate cycle and peripherally related burdens. The advantage of Steve's method is that it neatly solves an issue preventing a "pull" optimization from being deployed. In the end, we ended up deploying Steve's idea. But it later dawned on me that we could get the best of both worlds by deploying both ideas together, albeit slightly modified. The idea is simple: Use a "light-weight" lookup for pre-routing, since we only need to approximate a good home for the task. And we also retain the post-routing push logic to clean up any inaccuracies caused by a condition of "priority mistargeting" caused by the lightweight lookup. Most of the time, the pre-routing should work and yield lower overhead. In the cases where it doesnt, the post-router will bat cleanup. Signed-off-by: Gregory Haskins <ghaskins@novell.com> Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: RT balancing: include current CPUGregory Haskins2008-01-25
| | | | | | | | | | | | It doesn't hurt if we allow the current CPU to be included in the search. We will just simply skip it later if the current CPU turns out to be the lowest. We will use this later in the series Signed-off-by: Gregory Haskins <ghaskins@novell.com> Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: break out search for RT tasksGregory Haskins2008-01-25
| | | | | | | | | Isolate the search logic into a function so that it can be used later in places other than find_locked_lowest_rq(). Signed-off-by: Gregory Haskins <ghaskins@novell.com> Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: de-SCHED_OTHER-ize the RT pathGregory Haskins2008-01-25
| | | | | | | | | | | | | | | | The current wake-up code path tries to determine if it can optimize the wake-up to "this_cpu" by computing load calculations. The problem is that these calculations are only relevant to SCHED_OTHER tasks where load is king. For RT tasks, priority is king. So the load calculation is completely wasted bandwidth. Therefore, we create a new sched_class interface to help with pre-wakeup routing decisions and move the load calculation as a function of CFS task's class. Signed-off-by: Gregory Haskins <ghaskins@novell.com> Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: clean up this_rq use in kernel/sched_rt.cGregory Haskins2008-01-25
| | | | | | | | | | "this_rq" is normally used to denote the RQ on the current cpu (i.e. "cpu_rq(this_cpu)"). So clean up the usage of this_rq to be more consistent with the rest of the code. Signed-off-by: Gregory Haskins <ghaskins@novell.com> Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: add RT-balance cpu-weightGregory Haskins2008-01-25
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Some RT tasks (particularly kthreads) are bound to one specific CPU. It is fairly common for two or more bound tasks to get queued up at the same time. Consider, for instance, softirq_timer and softirq_sched. A timer goes off in an ISR which schedules softirq_thread to run at RT50. Then the timer handler determines that it's time to smp-rebalance the system so it schedules softirq_sched to run. So we are in a situation where we have two RT50 tasks queued, and the system will go into rt-overload condition to request other CPUs for help. This causes two problems in the current code: 1) If a high-priority bound task and a low-priority unbounded task queue up behind the running task, we will fail to ever relocate the unbounded task because we terminate the search on the first unmovable task. 2) We spend precious futile cycles in the fast-path trying to pull overloaded tasks over. It is therefore optimial to strive to avoid the overhead all together if we can cheaply detect the condition before overload even occurs. This patch tries to achieve this optimization by utilizing the hamming weight of the task->cpus_allowed mask. A weight of 1 indicates that the task cannot be migrated. We will then utilize this information to skip non-migratable tasks and to eliminate uncessary rebalance attempts. We introduce a per-rq variable to count the number of migratable tasks that are currently running. We only go into overload if we have more than one rt task, AND at least one of them is migratable. In addition, we introduce a per-task variable to cache the cpus_allowed weight, since the hamming calculation is probably relatively expensive. We only update the cached value when the mask is updated which should be relatively infrequent, especially compared to scheduling frequency in the fast path. Signed-off-by: Gregory Haskins <ghaskins@novell.com> Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: disable standard balancer for RT tasksSteven Rostedt2008-01-25
| | | | | | | | | | Since we now take an active approach to load balancing, we don't need to balance RT tasks via the normal task balancer. In fact, this code was found to pull RT tasks away from CPUS that the active movement performed, resulting in large latencies. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: push RT tasks from overloaded CPUsSteven Rostedt2008-01-25
| | | | | | | | | | This patch adds pushing of overloaded RT tasks from a runqueue that is having tasks (most likely RT tasks) added to the run queue. TODO: We don't cover the case of waking of new RT tasks (yet). Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: pull RT tasks from overloaded runqueuesSteven Rostedt2008-01-25
| | | | | | | | | | | | | This patch adds the algorithm to pull tasks from RT overloaded runqueues. When a pull RT is initiated, all overloaded runqueues are examined for a RT task that is higher in prio than the highest prio task queued on the target runqueue. If another runqueue holds a RT task that is of higher prio than the highest prio task on the target runqueue is found it is pulled to the target runqueue. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: add rt-overload trackingSteven Rostedt2008-01-25
| | | | | | | | | This patch adds an RT overload accounting system. When a runqueue has more than one RT task queued, it is marked as overloaded. That is that it is a candidate to have RT tasks pulled from it. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: add RT task pushingSteven Rostedt2008-01-25
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch adds an algorithm to push extra RT tasks off a run queue to other CPU runqueues. When more than one RT task is added to a run queue, this algorithm takes an assertive approach to push the RT tasks that are not running onto other run queues that have lower priority. The way this works is that the highest RT task that is not running is looked at and we examine the runqueues on the CPUS for that tasks affinity mask. We find the runqueue with the lowest prio in the CPU affinity of the picked task, and if it is lower in prio than the picked task, we push the task onto that CPU runqueue. We continue pushing RT tasks off the current runqueue until we don't push any more. The algorithm stops when the next highest RT task can't preempt any other processes on other CPUS. TODO: The algorithm may stop when there are still RT tasks that can be migrated. Specifically, if the highest non running RT task CPU affinity is restricted to CPUs that are running higher priority tasks, there may be a lower priority task queued that has an affinity with a CPU that is running a lower priority task that it could be migrated to. This patch set does not address this issue. Note: checkpatch reveals two over 80 character instances. I'm not sure that breaking them up will help visually, so I left them as is. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: track highest prio task queuedSteven Rostedt2008-01-25
| | | | | | | | | | | | This patch adds accounting to each runqueue to keep track of the highest prio task queued on the run queue. We only care about RT tasks, so if the run queue does not contain any active RT tasks its priority will be considered MAX_RT_PRIO. This information will be used for later patches. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: count # of queued RT tasksSteven Rostedt2008-01-25
| | | | | | | | This patch adds accounting to keep track of the number of RT tasks running on a runqueue. This information will be used in later patches. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* softlockup: automatically detect hung TASK_UNINTERRUPTIBLE tasksIngo Molnar2008-01-25
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | this patch extends the soft-lockup detector to automatically detect hung TASK_UNINTERRUPTIBLE tasks. Such hung tasks are printed the following way: ------------------> INFO: task prctl:3042 blocked for more than 120 seconds. "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message prctl D fd5e3793 0 3042 2997 f6050f38 00000046 00000001 fd5e3793 00000009 c06d8264 c06dae80 00000286 f6050f40 f6050f00 f7d34d90 f7d34fc8 c1e1be80 00000001 f6050000 00000000 f7e92d00 00000286 f6050f18 c0489d1a f6050f40 00006605 00000000 c0133a5b Call Trace: [<c04883a5>] schedule_timeout+0x6d/0x8b [<c04883d8>] schedule_timeout_uninterruptible+0x15/0x17 [<c0133a76>] msleep+0x10/0x16 [<c0138974>] sys_prctl+0x30/0x1e2 [<c0104c52>] sysenter_past_esp+0x5f/0xa5 ======================= 2 locks held by prctl/3042: #0: (&sb->s_type->i_mutex_key#5){--..}, at: [<c0197d11>] do_fsync+0x38/0x7a #1: (jbd_handle){--..}, at: [<c01ca3d2>] journal_start+0xc7/0xe9 <------------------ the current default timeout is 120 seconds. Such messages are printed up to 10 times per bootup. If the system has crashed already then the messages are not printed. if lockdep is enabled then all held locks are printed as well. this feature is a natural extension to the softlockup-detector (kernel locked up without scheduling) and to the NMI watchdog (kernel locked up with IRQs disabled). [ Gautham R Shenoy <ego@in.ibm.com>: CPU hotplug fixes. ] [ Andrew Morton <akpm@linux-foundation.org>: build warning fix. ] Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
* cpu-hotplug: fix build on !CONFIG_SMPIngo Molnar2008-01-25
| | | | | | fix build on !CONFIG_SMP. Signed-off-by: Ingo Molnar <mingo@elte.hu>
* cpu-hotplug: replace per-subsystem mutexes with get_online_cpus()Gautham R Shenoy2008-01-25
| | | | | | | | | This patch converts the known per-subsystem mutexes to get_online_cpus put_online_cpus. It also eliminates the CPU_LOCK_ACQUIRE and CPU_LOCK_RELEASE hotplug notification events. Signed-off-by: Gautham R Shenoy <ego@in.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* cpu-hotplug: replace lock_cpu_hotplug() with get_online_cpus()Gautham R Shenoy2008-01-25
| | | | | | | | | | | | | | | | | Replace all lock_cpu_hotplug/unlock_cpu_hotplug from the kernel and use get_online_cpus and put_online_cpus instead as it highlights the refcount semantics in these operations. The new API guarantees protection against the cpu-hotplug operation, but it doesn't guarantee serialized access to any of the local data structures. Hence the changes needs to be reviewed. In case of pseries_add_processor/pseries_remove_processor, use cpu_maps_update_begin()/cpu_maps_update_done() as we're modifying the cpu_present_map there. Signed-off-by: Gautham R Shenoy <ego@in.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* cpu-hotplug: refcount based cpu hotplugGautham R Shenoy2008-01-25
| | | | | | | | | | | | | | | | This patch implements a Refcount + Waitqueue based model for cpu-hotplug. Now, a thread which wants to prevent cpu-hotplug, will bump up a global refcount and the thread which wants to perform a cpu-hotplug operation will block till the global refcount goes to zero. The readers, if any, during an ongoing cpu-hotplug operation are blocked until the cpu-hotplug operation is over. Signed-off-by: Gautham R Shenoy <ego@in.ibm.com> Signed-off-by: Paul Jackson <pj@sgi.com> [For !CONFIG_HOTPLUG_CPU ] Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: group scheduler, fix fairness of cpu bandwidth allocation for task groupsSrivatsa Vaddagiri2008-01-25
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The current load balancing scheme isn't good enough for precise group fairness. For example: on a 8-cpu system, I created 3 groups as under: a = 8 tasks (cpu.shares = 1024) b = 4 tasks (cpu.shares = 1024) c = 3 tasks (cpu.shares = 1024) a, b and c are task groups that have equal weight. We would expect each of the groups to receive 33.33% of cpu bandwidth under a fair scheduler. This is what I get with the latest scheduler git tree: Signed-off-by: Ingo Molnar <mingo@elte.hu> -------------------------------------------------------------------------------- Col1 | Col2 | Col3 | Col4 ------|---------|-------|------------------------------------------------------- a | 277.676 | 57.8% | 54.1% 54.1% 54.1% 54.2% 56.7% 62.2% 62.8% 64.5% b | 116.108 | 24.2% | 47.4% 48.1% 48.7% 49.3% c | 86.326 | 18.0% | 47.5% 47.9% 48.5% -------------------------------------------------------------------------------- Explanation of o/p: Col1 -> Group name Col2 -> Cumulative execution time (in seconds) received by all tasks of that group in a 60sec window across 8 cpus Col3 -> CPU bandwidth received by the group in the 60sec window, expressed in percentage. Col3 data is derived as: Col3 = 100 * Col2 / (NR_CPUS * 60) Col4 -> CPU bandwidth received by each individual task of the group. Col4 = 100 * cpu_time_recd_by_task / 60 [I can share the test case that produces a similar o/p if reqd] The deviation from desired group fairness is as below: a = +24.47% b = -9.13% c = -15.33% which is quite high. After the patch below is applied, here are the results: -------------------------------------------------------------------------------- Col1 | Col2 | Col3 | Col4 ------|---------|-------|------------------------------------------------------- a | 163.112 | 34.0% | 33.2% 33.4% 33.5% 33.5% 33.7% 34.4% 34.8% 35.3% b | 156.220 | 32.5% | 63.3% 64.5% 66.1% 66.5% c | 160.653 | 33.5% | 85.8% 90.6% 91.4% -------------------------------------------------------------------------------- Deviation from desired group fairness is as below: a = +0.67% b = -0.83% c = +0.17% which is far better IMO. Most of other runs have yielded a deviation within +-2% at the most, which is good. Why do we see bad (group) fairness with current scheuler? ========================================================= Currently cpu's weight is just the summation of individual task weights. This can yield incorrect results. For ex: consider three groups as below on a 2-cpu system: CPU0 CPU1 --------------------------- A (10) B(5) C(5) --------------------------- Group A has 10 tasks, all on CPU0, Group B and C have 5 tasks each all of which are on CPU1. Each task has the same weight (NICE_0_LOAD = 1024). The current scheme would yield a cpu weight of 10240 (10*1024) for each cpu and the load balancer will think both CPUs are perfectly balanced and won't move around any tasks. This, however, would yield this bandwidth: A = 50% B = 25% C = 25% which is not the desired result. What's changing in the patch? ============================= - How cpu weights are calculated when CONFIF_FAIR_GROUP_SCHED is defined (see below) - API Change - Two tunables introduced in sysfs (under SCHED_DEBUG) to control the frequency at which the load balance monitor thread runs. The basic change made in this patch is how cpu weight (rq->load.weight) is calculated. Its now calculated as the summation of group weights on a cpu, rather than summation of task weights. Weight exerted by a group on a cpu is dependent on the shares allocated to it and also the number of tasks the group has on that cpu compared to the total number of (runnable) tasks the group has in the system. Let, W(K,i) = Weight of group K on cpu i T(K,i) = Task load present in group K's cfs_rq on cpu i T(K) = Total task load of group K across various cpus S(K) = Shares allocated to group K NRCPUS = Number of online cpus in the scheduler domain to which group K is assigned. Then, W(K,i) = S(K) * NRCPUS * T(K,i) / T(K) A load balance monitor thread is created at bootup, which periodically runs and adjusts group's weight on each cpu. To avoid its overhead, two min/max tunables are introduced (under SCHED_DEBUG) to control the rate at which it runs. Fixes from: Peter Zijlstra <a.p.zijlstra@chello.nl> - don't start the load_balance_monitor when there is only a single cpu. - rename the kthread because its currently longer than TASK_COMM_LEN Signed-off-by: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: introduce a mutex and corresponding API to serialize access to ↵Srivatsa Vaddagiri2008-01-25
| | | | | | | | | | | | | | | | | | | | | doms_curarray doms_cur[] array represents various scheduling domains which are mutually exclusive. Currently cpusets code can modify this array (by calling partition_sched_domains()) as a result of user modifying sched_load_balance flag for various cpusets. This patch introduces a mutex and corresponding API (only when CONFIG_FAIR_GROUP_SCHED is defined) which allows a reader to safely read the doms_cur[] array w/o worrying abt concurrent modifications to the array. The fair group scheduler code (introduced in next patch of this series) makes use of this mutex to walk thr' doms_cur[] array while rebalancing shares of task groups across cpus. Signed-off-by: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: group scheduling, change how cpu load is calculatedSrivatsa Vaddagiri2008-01-25
| | | | | | | | | | | | | | This patch changes how the cpu load exerted by fair_sched_class tasks is calculated. Load exerted by fair_sched_class tasks on a cpu is now a summation of the group weights, rather than summation of task weights. Weight exerted by a group on a cpu is dependent on the shares allocated to it. This version of patch has a minor impact on code size, but should have no runtime/functional impact for !CONFIG_FAIR_GROUP_SCHED. Signed-off-by: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: group scheduling, minor fixesSrivatsa Vaddagiri2008-01-25
| | | | | | | | | | | | | | Minor bug fixes for the group scheduler: - Use a mutex to serialize add/remove of task groups and also when changing shares of a task group. Use the same mutex when printing cfs_rq debugging stats for various task groups. - Use list_for_each_entry_rcu in for_each_leaf_cfs_rq macro (when walking task group list) Signed-off-by: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: group scheduling code cleanupSrivatsa Vaddagiri2008-01-25
| | | | | | | | | | Minor cleanups: - Fix coding style - remove obsolete comment Signed-off-by: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: remove printk_clock references from ia64Ingo Molnar2008-01-25
| | | | | | remove remaining printk_clock references from ia64. Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: remove printk_clock()Ingo Molnar2008-01-25
| | | | | | printk_clock() is obsolete - it has been replaced with cpu_clock(). Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: fix CONFIG_PRINT_TIME's reliance on sched_clock()Ingo Molnar2008-01-25
| | | | | | | | | | | | | Stefano Brivio reported weird printk timestamp behavior during CPU frequency changes: http://bugzilla.kernel.org/show_bug.cgi?id=9475 fix CONFIG_PRINT_TIME's reliance on sched_clock() and use cpu_clock() instead. Reported-and-bisected-by: Stefano Brivio <stefano.brivio@polimi.it> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* printk: make printk more robust by not allowing recursionIngo Molnar2008-01-25
| | | | | | | | | | | | | | | | | make printk more robust by allowing recursion only if there's a crash going on. Also add recursion detection. I've tested it with an artificially injected printk recursion - instead of a lockup or spontaneous reboot or other crash, the output was a well controlled: [ 41.057335] SysRq : <2>BUG: recent printk recursion! [ 41.057335] loglevel0-8 reBoot Crashdump show-all-locks(D) tErm Full kIll saK showMem Nice powerOff showPc show-all-timers(Q) unRaw Sync showTasks Unmount shoW-blocked-tasks also do all this printk-debug logic with irqs disabled. Signed-off-by: Ingo Molnar <mingo@elte.hu> Reviewed-by: Nick Piggin <npiggin@suse.de>
* Merge branch 'for-linus' of ↵Linus Torvalds2008-01-25
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/selinux-2.6 * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/selinux-2.6: selinux: make mls_compute_sid always polyinstantiate security/selinux: constify function pointer tables and fields security: add a secctx_to_secid() hook security: call security_file_permission from rw_verify_area security: remove security_sb_post_mountroot hook Security: remove security.h include from mm.h Security: remove security_file_mmap hook sparse-warnings (NULL as 0). Security: add get, set, and cloning of superblock security information security/selinux: Add missing "space"
| * selinux: make mls_compute_sid always polyinstantiateEamon Walsh2008-01-24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch removes the requirement that the new and related object types differ in order to polyinstantiate by MLS level. This allows MLS polyinstantiation to occur in the absence of explicit type_member rules or when the type has not changed. Potential users of this support include pam_namespace.so (directory polyinstantiation) and the SELinux X support (property polyinstantiation). Signed-off-by: Eamon Walsh <ewalsh@tycho.nsa.gov> Acked-by: Stephen Smalley <sds@tycho.nsa.gov> Signed-off-by: James Morris <jmorris@namei.org>
| * security/selinux: constify function pointer tables and fieldsJan Engelhardt2008-01-24
| | | | | | | | | | | | | | Constify function pointer tables and fields. Signed-off-by: Jan Engelhardt <jengelh@computergmbh.de> Signed-off-by: James Morris <jmorris@namei.org>
| * security: add a secctx_to_secid() hookDavid Howells2008-01-24
| | | | | | | | | | | | | | | | | | | | Add a secctx_to_secid() LSM hook to go along with the existing secid_to_secctx() LSM hook. This patch also includes the SELinux implementation for this hook. Signed-off-by: Paul Moore <paul.moore@hp.com> Acked-by: Stephen Smalley <sds@tycho.nsa.gov> Signed-off-by: James Morris <jmorris@namei.org>
| * security: call security_file_permission from rw_verify_areaJames Morris2008-01-24
| | | | | | | | | | | | | | | | All instances of rw_verify_area() are followed by a call to security_file_permission(), so just call the latter from the former. Acked-by: Eric Paris <eparis@redhat.com> Signed-off-by: James Morris <jmorris@namei.org>
| * security: remove security_sb_post_mountroot hookH. Peter Anvin2008-01-24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The security_sb_post_mountroot() hook is long-since obsolete, and is fundamentally broken: it is never invoked if someone uses initramfs. This is particularly damaging, because the existence of this hook has been used as motivation for not using initramfs. Stephen Smalley confirmed on 2007-07-19 that this hook was originally used by SELinux but can now be safely removed: http://marc.info/?l=linux-kernel&m=118485683612916&w=2 Cc: Stephen Smalley <sds@tycho.nsa.gov> Cc: James Morris <jmorris@namei.org> Cc: Eric Paris <eparis@parisplace.org> Cc: Chris Wright <chrisw@sous-sol.org> Signed-off-by: H. Peter Anvin <hpa@zytor.com> Signed-off-by: James Morris <jmorris@namei.org>
| * Security: remove security.h include from mm.hJames Morris2008-01-24
| | | | | | | | | | | | | | | | | | Remove security.h include from mm.h, as it is only needed for a single extern declaration, and pulls in all kinds of crud. Fine-by-me: David Chinner <dgc@sgi.com> Acked-by: Eric Paris <eparis@redhat.com> Signed-off-by: James Morris <jmorris@namei.org>
| * Security: remove security_file_mmap hook sparse-warnings (NULL as 0).Richard Knutsson2008-01-24
| | | | | | | | | | | | | | | | | | | | | | Fixing: CHECK mm/mmap.c mm/mmap.c:1623:29: warning: Using plain integer as NULL pointer mm/mmap.c:1623:29: warning: Using plain integer as NULL pointer mm/mmap.c:1944:29: warning: Using plain integer as NULL pointer Signed-off-by: Richard Knutsson <ricknu-0@student.ltu.se> Signed-off-by: James Morris <jmorris@namei.org>