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* Merge branch 'sched-urgent-for-linus' of ↵Linus Torvalds2012-08-205-19/+70
|\ | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull scheduler fixes from Ingo Molnar. * 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: sched: Fix migration thread runtime bogosity sched,rt: fix isolated CPUs leaving root_task_group indefinitely throttled sched,cgroup: Fix up task_groups list sched: fix divide by zero at {thread_group,task}_times sched, cgroup: Reduce rq->lock hold times for large cgroup hierarchies
| * sched: Fix migration thread runtime bogosityMike Galbraith2012-08-131-1/+21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Make stop scheduler class do the same accounting as other classes, Migration threads can be caught in the act while doing exec balancing, leading to the below due to use of unmaintained ->se.exec_start. The load that triggered this particular instance was an apparently out of control heavily threaded application that does system monitoring in what equated to an exec bomb, with one of the VERY frequently migrated tasks being ps. %CPU PID USER CMD 99.3 45 root [migration/10] 97.7 53 root [migration/12] 97.0 57 root [migration/13] 90.1 49 root [migration/11] 89.6 65 root [migration/15] 88.7 17 root [migration/3] 80.4 37 root [migration/8] 78.1 41 root [migration/9] 44.2 13 root [migration/2] Signed-off-by: Mike Galbraith <mgalbraith@suse.de> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1344051854.6739.19.camel@marge.simpson.net Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * sched,rt: fix isolated CPUs leaving root_task_group indefinitely throttledMike Galbraith2012-08-131-0/+13
| | | | | | | | | | | | | | | | | | | | | | Root task group bandwidth replenishment must service all CPUs, regardless of where the timer was last started, and regardless of the isolation mechanism, lest 'Quoth the Raven, "Nevermore"' become rt scheduling policy. Signed-off-by: Mike Galbraith <efault@gmx.de> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1344326558.6968.25.camel@marge.simpson.net Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * sched,cgroup: Fix up task_groups listMike Galbraith2012-08-132-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | With multiple instances of task_groups, for_each_rt_rq() is a noop, no task groups having been added to the rt.c list instance. This renders __enable/disable_runtime() and print_rt_stats() noop, the user (non) visible effect being that rt task groups are missing in /proc/sched_debug. Signed-off-by: Mike Galbraith <efault@gmx.de> Cc: stable@kernel.org # v3.3+ Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1344308413.6846.7.camel@marge.simpson.net Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * sched: fix divide by zero at {thread_group,task}_timesStanislaw Gruszka2012-08-131-14/+20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | On architectures where cputime_t is 64 bit type, is possible to trigger divide by zero on do_div(temp, (__force u32) total) line, if total is a non zero number but has lower 32 bit's zeroed. Removing casting is not a good solution since some do_div() implementations do cast to u32 internally. This problem can be triggered in practice on very long lived processes: PID: 2331 TASK: ffff880472814b00 CPU: 2 COMMAND: "oraagent.bin" #0 [ffff880472a51b70] machine_kexec at ffffffff8103214b #1 [ffff880472a51bd0] crash_kexec at ffffffff810b91c2 #2 [ffff880472a51ca0] oops_end at ffffffff814f0b00 #3 [ffff880472a51cd0] die at ffffffff8100f26b #4 [ffff880472a51d00] do_trap at ffffffff814f03f4 #5 [ffff880472a51d60] do_divide_error at ffffffff8100cfff #6 [ffff880472a51e00] divide_error at ffffffff8100be7b [exception RIP: thread_group_times+0x56] RIP: ffffffff81056a16 RSP: ffff880472a51eb8 RFLAGS: 00010046 RAX: bc3572c9fe12d194 RBX: ffff880874150800 RCX: 0000000110266fad RDX: 0000000000000000 RSI: ffff880472a51eb8 RDI: 001038ae7d9633dc RBP: ffff880472a51ef8 R8: 00000000b10a3a64 R9: ffff880874150800 R10: 00007fcba27ab680 R11: 0000000000000202 R12: ffff880472a51f08 R13: ffff880472a51f10 R14: 0000000000000000 R15: 0000000000000007 ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018 #7 [ffff880472a51f00] do_sys_times at ffffffff8108845d #8 [ffff880472a51f40] sys_times at ffffffff81088524 #9 [ffff880472a51f80] system_call_fastpath at ffffffff8100b0f2 RIP: 0000003808caac3a RSP: 00007fcba27ab6d8 RFLAGS: 00000202 RAX: 0000000000000064 RBX: ffffffff8100b0f2 RCX: 0000000000000000 RDX: 00007fcba27ab6e0 RSI: 000000000076d58e RDI: 00007fcba27ab6e0 RBP: 00007fcba27ab700 R8: 0000000000000020 R9: 000000000000091b R10: 00007fcba27ab680 R11: 0000000000000202 R12: 00007fff9ca41940 R13: 0000000000000000 R14: 00007fcba27ac9c0 R15: 00007fff9ca41940 ORIG_RAX: 0000000000000064 CS: 0033 SS: 002b Cc: stable@vger.kernel.org Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/20120808092714.GA3580@redhat.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * sched, cgroup: Reduce rq->lock hold times for large cgroup hierarchiesPeter Zijlstra2012-08-132-3/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Peter Portante reported that for large cgroup hierarchies (and or on large CPU counts) we get immense lock contention on rq->lock and stuff stops working properly. His workload was a ton of processes, each in their own cgroup, everybody idling except for a sporadic wakeup once every so often. It was found that: schedule() idle_balance() load_balance() local_irq_save() double_rq_lock() update_h_load() walk_tg_tree(tg_load_down) tg_load_down() Results in an entire cgroup hierarchy walk under rq->lock for every new-idle balance and since new-idle balance isn't throttled this results in a lot of work while holding the rq->lock. This patch does two things, it removes the work from under rq->lock based on the good principle of race and pray which is widely employed in the load-balancer as a whole. And secondly it throttles the update_h_load() calculation to max once per jiffy. I considered excluding update_h_load() for new-idle balance all-together, but purely relying on regular balance passes to update this data might not work out under some rare circumstances where the new-idle busiest isn't the regular busiest for a while (unlikely, but a nightmare to debug if someone hits it and suffers). Cc: pjt@google.com Cc: Larry Woodman <lwoodman@redhat.com> Cc: Mike Galbraith <efault@gmx.de> Reported-by: Peter Portante <pportant@redhat.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/n/tip-aaarrzfpnaam7pqrekofu8a6@git.kernel.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* | Merge branch 'sched-urgent-for-linus' of ↵Linus Torvalds2012-08-033-23/+20Star
|\| | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull scheduler fixes from Ingo Molnar: "Fixes and two late cleanups" * 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: sched/cleanups: Add load balance cpumask pointer to 'struct lb_env' sched: Fix comment about PREEMPT_ACTIVE bit location sched: Fix minor code style issues sched: Use task_rq_unlock() in __sched_setscheduler() sched/numa: Add SD_PERFER_SIBLING to CPU domain
| * sched/cleanups: Add load balance cpumask pointer to 'struct lb_env'Michael Wang2012-07-311-15/+14Star
| | | | | | | | | | | | | | | | | | | | With this patch struct ld_env will have a pointer of the load balancing cpumask and we don't need to pass a cpumask around anymore. Signed-off-by: Michael Wang <wangyun@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/4FFE8665.3080705@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * sched: Fix minor code style issuesYing Xue2012-07-261-5/+5
| | | | | | | | | | | | | | | | | | Delete redudant spaces between type name and data name or operators. Signed-off-by: Ying Xue <ying.xue0@gmail.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1342076622-6606-1-git-send-email-ying.xue0@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * sched: Use task_rq_unlock() in __sched_setscheduler()Namhyung Kim2012-07-261-3/+1Star
| | | | | | | | | | | | | | | | | | | | | | It seems there's no specific reason to open-code it. I guess commit 0122ec5b02f76 ("sched: Add p->pi_lock to task_rq_lock()") simply missed it. Let's be consistent with others. Signed-off-by: Namhyung Kim <namhyung@kernel.org> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1341647342-6742-1-git-send-email-namhyung@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | Merge branch 'perf-core-for-linus' of ↵Linus Torvalds2012-08-011-1/+1
|\ \ | |/ |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull perf updates from Ingo Molnar: "The biggest changes are Intel Nehalem-EX PMU uncore support, uprobes updates/cleanups/fixes from Oleg and diverse tooling updates (mostly fixes) now that Arnaldo is back from vacation." * 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (40 commits) uprobes: __replace_page() needs munlock_vma_page() uprobes: Rename vma_address() and make it return "unsigned long" uprobes: Fix register_for_each_vma()->vma_address() check uprobes: Introduce vaddr_to_offset(vma, vaddr) uprobes: Teach build_probe_list() to consider the range uprobes: Remove insert_vm_struct()->uprobe_mmap() uprobes: Remove copy_vma()->uprobe_mmap() uprobes: Fix overflow in vma_address()/find_active_uprobe() uprobes: Suppress uprobe_munmap() from mmput() uprobes: Uprobe_mmap/munmap needs list_for_each_entry_safe() uprobes: Clean up and document write_opcode()->lock_page(old_page) uprobes: Kill write_opcode()->lock_page(new_page) uprobes: __replace_page() should not use page_address_in_vma() uprobes: Don't recheck vma/f_mapping in write_opcode() perf/x86: Fix missing struct before structure name perf/x86: Fix format definition of SNB-EP uncore QPI box perf/x86: Make bitfield unsigned perf/x86: Fix LLC-* and node-* events on Intel SandyBridge perf/x86: Add Intel Nehalem-EX uncore support perf/x86: Fix typo in format definition of uncore PCU filter ...
| * sched: Deliver sched_switch events to the current taskAndrew Vagin2012-07-261-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Otherwise they can't be filtered for a defined task: perf record -e sched:sched_switch ./foo This command doesn't report any events without this patch. I think it isn't a security concern if someone knows who will be executed next - this can already be observed by polling /proc state. By default perf is disabled for non-root users in any case. I need these events for profiling sleep times. sched_switch is used for getting callchains and sched_stat_* is used for getting time periods. These events are combined in user space, then it can be analyzed by perf tools. Signed-off-by: Andrew Vagin <avagin@openvz.org> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Arun Sharma <asharma@fb.com> Link: http://lkml.kernel.org/r/1342088069-1005148-1-git-send-email-avagin@openvz.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | sched: Fix race in task_group()Peter Zijlstra2012-07-242-14/+18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Stefan reported a crash on a kernel before a3e5d1091c1 ("sched: Don't call task_group() too many times in set_task_rq()"), he found the reason to be that the multiple task_group() invocations in set_task_rq() returned different values. Looking at all that I found a lack of serialization and plain wrong comments. The below tries to fix it using an extra pointer which is updated under the appropriate scheduler locks. Its not pretty, but I can't really see another way given how all the cgroup stuff works. Reported-and-tested-by: Stefan Bader <stefan.bader@canonical.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1340364965.18025.71.camel@twins Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | sched: Improve balance_cpu() to consider other cpus in its group as target ↵Srivatsa Vaddagiri2012-07-241-4/+74
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | of (pinned) task Current load balance scheme requires only one cpu in a sched_group (balance_cpu) to look at other peer sched_groups for imbalance and pull tasks towards itself from a busy cpu. Tasks thus pulled by balance_cpu could later get picked up by cpus that are in the same sched_group as that of balance_cpu. This scheme however fails to pull tasks that are not allowed to run on balance_cpu (but are allowed to run on other cpus in its sched_group). That can affect fairness and in some worst case scenarios cause starvation. Consider a two core (2 threads/core) system running tasks as below: Core0 Core1 / \ / \ C0 C1 C2 C3 | | | | v v v v F0 T1 F1 [idle] T2 F0 = SCHED_FIFO task (pinned to C0) F1 = SCHED_FIFO task (pinned to C2) T1 = SCHED_OTHER task (pinned to C1) T2 = SCHED_OTHER task (pinned to C1 and C2) F1 could become a cpu hog, which will starve T2 unless C1 pulls it. Between C0 and C1 however, C0 is required to look for imbalance between cores, which will fail to pull T2 towards Core0. T2 will starve eternally in this case. The same scenario can arise in presence of non-rt tasks as well (say we replace F1 with high irq load). We tackle this problem by having balance_cpu move pinned tasks to one of its sibling cpus (where they can run). We first check if load balance goal can be met by ignoring pinned tasks, failing which we retry move_tasks() with a new env->dst_cpu. This patch modifies load balance semantics on who can move load towards a given cpu in a given sched_domain. Before this patch, a given_cpu or a ilb_cpu acting on behalf of an idle given_cpu is responsible for moving load to given_cpu. With this patch applied, balance_cpu can in addition decide on moving some load to a given_cpu. There is a remote possibility that excess load could get moved as a result of this (balance_cpu and given_cpu/ilb_cpu deciding *independently* and at *same* time to move some load to a given_cpu). However we should see less of such conflicting decisions in practice and moreover subsequent load balance cycles should correct the excess load moved to given_cpu. Signed-off-by: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> Signed-off-by: Prashanth Nageshappa <prashanth@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/4FE06CDB.2060605@linux.vnet.ibm.com [ minor edits ] Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | sched: Reset loop counters if all tasks are pinned and we need to redo load ↵Prashanth Nageshappa2012-07-241-1/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | balance While load balancing, if all tasks on the source runqueue are pinned, we retry after excluding the corresponding source cpu. However, loop counters env.loop and env.loop_break are not reset before retrying, which can lead to failure in moving the tasks. In this patch we reset env.loop and env.loop_break to their inital values before we retry. Signed-off-by: Prashanth Nageshappa <prashanth@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/4FE06EEF.2090709@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | sched: Reorder 'struct lb_env' members to reduce its sizePrashanth Nageshappa2012-07-241-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | Members of 'struct lb_env' are not in appropriate order to reuse compiler added padding on 64bit architectures. In this patch we reorder those struct members and help reduce the size of the structure from 96 bytes to 80 bytes on 64 bit architectures. Suggested-by: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> Signed-off-by: Prashanth Nageshappa <prashanth@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/4FE06DDE.7000403@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | sched: Improve scalability via 'CPU buddies', which withstand random ↵Mike Galbraith2012-07-242-22/+45
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | perturbations Traversing an entire package is not only expensive, it also leads to tasks bouncing all over a partially idle and possible quite large package. Fix that up by assigning a 'buddy' CPU to try to motivate. Each buddy may try to motivate that one other CPU, if it's busy, tough, it may then try its SMT sibling, but that's all this optimization is allowed to cost. Sibling cache buddies are cross-wired to prevent bouncing. 4 socket 40 core + SMT Westmere box, single 30 sec tbench runs, higher is better: clients 1 2 4 8 16 32 64 128 .......................................................................... pre 30 41 118 645 3769 6214 12233 14312 post 299 603 1211 2418 4697 6847 11606 14557 A nice increase in performance. Signed-off-by: Mike Galbraith <efault@gmx.de> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1339471112.7352.32.camel@marge.simpson.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | cpusets, hotplug: Restructure functions that are invoked during hotplugSrivatsa S. Bhat2012-07-241-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Separate out the cpuset related handling for CPU/Memory online/offline. This also helps us exploit the most obvious and basic level of optimization that any notification mechanism (CPU/Mem online/offline) has to offer us: "We *know* why we have been invoked. So stop pretending that we are lost, and do only the necessary amount of processing!". And while at it, rename scan_for_empty_cpusets() to scan_cpusets_upon_hotplug(), which is more appropriate considering how it is restructured. Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20120524141650.3692.48637.stgit@srivatsabhat.in.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | CPU hotplug, cpusets, suspend: Don't modify cpusets during suspend/resumeSrivatsa S. Bhat2012-07-241-4/+36
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In the event of CPU hotplug, the kernel modifies the cpusets' cpus_allowed masks as and when necessary to ensure that the tasks belonging to the cpusets have some place (online CPUs) to run on. And regular CPU hotplug is destructive in the sense that the kernel doesn't remember the original cpuset configurations set by the user, across hotplug operations. However, suspend/resume (which uses CPU hotplug) is a special case in which the kernel has the responsibility to restore the system (during resume), to exactly the same state it was in before suspend. In order to achieve that, do the following: 1. Don't modify cpusets during suspend/resume. At all. In particular, don't move the tasks from one cpuset to another, and don't modify any cpuset's cpus_allowed mask. So, simply ignore cpusets during the CPU hotplug operations that are carried out in the suspend/resume path. 2. However, cpusets and sched domains are related. We just want to avoid altering cpusets alone. So, to keep the sched domains updated, build a single sched domain (containing all active cpus) during each of the CPU hotplug operations carried out in s/r path, effectively ignoring the cpusets' cpus_allowed masks. (Since userspace is frozen while doing all this, it will go unnoticed.) 3. During the last CPU online operation during resume, build the sched domains by looking up the (unaltered) cpusets' cpus_allowed masks. That will bring back the system to the same original state as it was in before suspend. Ultimately, this will not only solve the cpuset problem related to suspend resume (ie., restores the cpusets to exactly what it was before suspend, by not touching it at all) but also speeds up suspend/resume because we avoid running cpuset update code for every CPU being offlined/onlined. Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20120524141611.3692.20155.stgit@srivatsabhat.in.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
*-. Merge branches 'core-urgent-for-linus', 'perf-urgent-for-linus' and ↵Linus Torvalds2012-07-143-76/+203
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull RCU, perf, and scheduler fixes from Ingo Molnar. The RCU fix is a revert for an optimization that could cause deadlocks. One of the scheduler commits (164c33c6adee "sched: Fix fork() error path to not crash") is correct but not complete (some architectures like Tile are not covered yet) - the resulting additional fixes are still WIP and Ingo did not want to delay these pending fixes. See this thread on lkml: [PATCH] fork: fix error handling in dup_task() The perf fixes are just trivial oneliners. * 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: Revert "rcu: Move PREEMPT_RCU preemption to switch_to() invocation" * 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: perf kvm: Fix segfault with report and mixed guestmount use perf kvm: Fix regression with guest machine creation perf script: Fix format regression due to libtraceevent merge ring-buffer: Fix accounting of entries when removing pages ring-buffer: Fix crash due to uninitialized new_pages list head * 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: MAINTAINERS/sched: Update scheduler file pattern sched/nohz: Rewrite and fix load-avg computation -- again sched: Fix fork() error path to not crash
| | * sched/nohz: Rewrite and fix load-avg computation -- againPeter Zijlstra2012-07-053-75/+203
| |/ |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Thanks to Charles Wang for spotting the defects in the current code: - If we go idle during the sample window -- after sampling, we get a negative bias because we can negate our own sample. - If we wake up during the sample window we get a positive bias because we push the sample to a known active period. So rewrite the entire nohz load-avg muck once again, now adding copious documentation to the code. Reported-and-tested-by: Doug Smythies <dsmythies@telus.net> Reported-and-tested-by: Charles Wang <muming.wq@gmail.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: stable@kernel.org Link: http://lkml.kernel.org/r/1340373782.18025.74.camel@twins [ minor edits ] Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * Revert "rcu: Move PREEMPT_RCU preemption to switch_to() invocation"Paul E. McKenney2012-07-021-1/+0Star
|/ | | | | | | | | | | | | This reverts commit 616c310e83b872024271c915c1b9ab505b9efad9. (Move PREEMPT_RCU preemption to switch_to() invocation). Testing by Sasha Levin <levinsasha928@gmail.com> showed that this can result in deadlock due to invoking the scheduler when one of the runqueue locks is held. Because this commit was simply a performance optimization, revert it. Reported-by: Sasha Levin <levinsasha928@gmail.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Tested-by: Sasha Levin <levinsasha928@gmail.com>
* Merge branch 'sched-urgent-for-linus' of ↵Linus Torvalds2012-06-084-39/+159
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull scheduler fixes from Ingo Molnar. * 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: sched: Fix the relax_domain_level boot parameter sched: Validate assumptions in sched_init_numa() sched: Always initialize cpu-power sched: Fix domain iteration sched/rt: Fix lockdep annotation within find_lock_lowest_rq() sched/numa: Load balance between remote nodes sched/x86: Calculate booted cores after construction of sibling_mask
| * sched: Fix the relax_domain_level boot parameterDimitri Sivanich2012-06-061-6/+3Star
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | It does not get processed because sched_domain_level_max is 0 at the time that setup_relax_domain_level() is run. Simply accept the value as it is, as we don't know the value of sched_domain_level_max until sched domain construction is completed. Fix sched_relax_domain_level in cpuset. The build_sched_domain() routine calls the set_domain_attribute() routine prior to setting the sd->level, however, the set_domain_attribute() routine relies on the sd->level to decide whether idle load balancing will be off/on. Signed-off-by: Dimitri Sivanich <sivanich@sgi.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/20120605184436.GA15668@sgi.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * sched: Validate assumptions in sched_init_numa()Peter Zijlstra2012-06-061-19/+80
| | | | | | | | | | | | | | | | | | | | | | | | Add some code to validate assumptions we're making and output warnings if they are not. If this trigger we want to know about it. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Alex Shi <lkml.alex@gmail.com> Link: http://lkml.kernel.org/n/tip-6uc3wk5s9udxtdl9cnku0vtt@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * sched: Always initialize cpu-powerPeter Zijlstra2012-06-062-2/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | Often when we run into mis-shapen topologies the balance iteration fails to update the cpu power properly and we'll end up in /0 traps. Always initialize the cpu-power to a semi-sane value so that we can at least boot the machine, even if the load-balancer might not function correctly. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/n/tip-3lbhyj25sr169ha7z3qht5na@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * sched: Fix domain iterationPeter Zijlstra2012-06-063-10/+61
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Weird topologies can lead to asymmetric domain setups. This needs further consideration since these setups are typically non-minimal too. For now, make it work by adding an extra mask selecting which CPUs are allowed to iterate up. The topology that triggered it is the one from David Rientjes: 10 20 20 30 20 10 20 20 20 20 10 20 30 20 20 10 resulting in boxes that wouldn't even boot. Reported-by: David Rientjes <rientjes@google.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/n/tip-3p86l9cuaqnxz7uxsojmz5rm@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * sched/rt: Fix lockdep annotation within find_lock_lowest_rq()Peter Zijlstra2012-06-061-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Roland Dreier reported spurious, hard to trigger lockdep warnings within the scheduler - without any real lockup. This bit gives us the right clue: > [89945.640512] [<ffffffff8103fa1a>] double_lock_balance+0x5a/0x90 > [89945.640568] [<ffffffff8104c546>] push_rt_task+0xc6/0x290 if you look at that code you'll find the double_lock_balance() in question is the one in find_lock_lowest_rq() [yay for inlining]. Now find_lock_lowest_rq() has a bug.. it fails to use double_unlock_balance() in one exit path, if this results in a retry in push_rt_task() we'll call double_lock_balance() again, at which point we'll run into said lockdep confusion. Reported-by: Roland Dreier <roland@kernel.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1337282386.4281.77.camel@twins Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * sched/numa: Load balance between remote nodesAlex Shi2012-06-061-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit cb83b629b ("sched/numa: Rewrite the CONFIG_NUMA sched domain support") removed the NODE sched domain and started checking if the node distance in SLIT table is farther than REMOTE_DISTANCE, if so, it will lose the load balance chance at exec/fork/wake_affine points. But actually, even the node distance is farther than REMOTE_DISTANCE. Modern CPUs also has QPI like connections, which ensures that memory access is not too slow between nodes. So the above change in behavior on NUMA machine causes a performance regression on various benchmarks: hackbench, tbench, netperf, oltp, etc. This patch will recover the scheduler behavior to old mode on all my Intel platforms: NHM EP/EX, WSM EP, SNB EP/EP4S, and thus fixes the perfromance regressions. (all of them just have 2 kinds distance, 10, 21) Signed-off-by: Alex Shi <alex.shi@intel.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1338965571-9812-1-git-send-email-alex.shi@intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | sched/fair: fix lots of kernel-doc warningsRandy Dunlap2012-06-081-16/+6Star
|/ | | | | | | | | | | | | | | | Fix lots of new kernel-doc warnings in kernel/sched/fair.c: Warning(kernel/sched/fair.c:3625): No description found for parameter 'env' Warning(kernel/sched/fair.c:3625): Excess function parameter 'sd' description in 'update_sg_lb_stats' Warning(kernel/sched/fair.c:3735): No description found for parameter 'env' Warning(kernel/sched/fair.c:3735): Excess function parameter 'sd' description in 'update_sd_pick_busiest' Warning(kernel/sched/fair.c:3735): Excess function parameter 'this_cpu' description in 'update_sd_pick_busiest' .. more warnings Signed-off-by: Randy Dunlap <rdunlap@xenotime.net> Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* sched: Remove NULL assignment of dattr_curKamalesh Babulal2012-05-301-1/+0Star
| | | | | | | | | | Remove explicit NULL assignment of static pointer dattr_cur from init_sched_domains(). Signed-off-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/20120523091411.GG5005@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched: Remove the last NULL entry from sched_feat_namesHiroshi Shimamoto2012-05-301-1/+0Star
| | | | | | | | | No need to have the last NULL entry. Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/4FBF29E7.5020805@ct.jp.nec.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched: Make sched_feat_names constHiroshi Shimamoto2012-05-301-1/+1
| | | | | | | | | The strings sched_feat_names are never changed. Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/4FBF29B2.9030904@ct.jp.nec.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched/rt: Fix SCHED_RR across cgroupsColin Cross2012-05-301-5/+10
| | | | | | | | | | | | | | | | | | | | task_tick_rt() has an optimization to only reschedule SCHED_RR tasks if they were the only element on their rq. However, with cgroups a SCHED_RR task could be the only element on its per-cgroup rq but still be competing with other SCHED_RR tasks in its parent's cgroup. In this case, the SCHED_RR task in the child cgroup would never yield at the end of its timeslice. If the child cgroup rt_runtime_us was the same as the parent cgroup rt_runtime_us, the task in the parent cgroup would starve completely. Modify task_tick_rt() to check that the task is the only task on its rq, and that the each of the scheduling entities of its ancestors is also the only entity on its rq. Signed-off-by: Colin Cross <ccross@android.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1337229266-15798-1-git-send-email-ccross@android.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched: Move nr_cpus_allowed out of 'struct sched_rt_entity'Peter Zijlstra2012-05-303-17/+23
| | | | | | | | | Since nr_cpus_allowed is used outside of sched/rt.c and wants to be used outside of there more, move it to a more natural site. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/n/tip-kr61f02y9brwzkh6x53pdptm@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched: Make sure to not re-read variables after validationPeter Zijlstra2012-05-301-4/+11
| | | | | | | | | | We could re-read rq->rt_avg after we validated it was smaller than total, invalidating the check and resulting in an unintended negative. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: David Rientjes <rientjes@google.com> Link: http://lkml.kernel.org/r/1337688268.9698.29.camel@twins Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched: Fix SD_OVERLAPPeter Zijlstra2012-05-302-7/+25
| | | | | | | | | | | | | | | | | | | | | | | | | | | | SD_OVERLAP exists to allow overlapping groups, overlapping groups appear in NUMA topologies that aren't fully connected. The typical result of not fully connected NUMA is that each cpu (or rather node) will have different spans for a particular distance. However due to how sched domains are traversed -- only the first cpu in the mask goes one level up -- the next level only cares about the spans of the cpus that went up. Due to this two things were observed to be broken: - build_overlap_sched_groups() -- since its possible the cpu we're building the groups for exists in multiple (or all) groups, the selection criteria of the first group didn't ensure there was a cpu for which is was true that cpumask_first(span) == cpu. Thus load- balancing would terminate. - update_group_power() -- assumed that the cpu span of the first group of the domain was covered by all groups of the child domain. The above explains why this isn't true, so deal with it. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: David Rientjes <rientjes@google.com> Link: http://lkml.kernel.org/r/1337788843.9783.14.camel@laptop Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched: Don't try allocating memory from offline nodesPeter Zijlstra2012-05-301-1/+1
| | | | | | | | | | | Allocators don't appreciate it when you try and allocate memory from offline nodes. Reported-and-tested-by: Tony Luck <tony.luck@intel.com> Reported-and-tested-by: Anton Blanchard <anton@samba.org> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/n/tip-epfc1io9whb7o22bcujf31vn@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched/nohz: Fix rq->cpu_load calculations some morePeter Zijlstra2012-05-301-10/+43
| | | | | | | | | | | | | | | | | | | | | | Follow up on commit 556061b00 ("sched/nohz: Fix rq->cpu_load[] calculations") since while that fixed the busy case it regressed the mostly idle case. Add a callback from the nohz exit to also age the rq->cpu_load[] array. This closes the hole where either there was no nohz load balance pass during the nohz, or there was a 'significant' amount of idle time between the last nohz balance and the nohz exit. So we'll update unconditionally from the tick to not insert any accidental 0 load periods while busy, and we try and catch up from nohz idle balance and nohz exit. Both these are still prone to missing a jiffy, but that has always been the case. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: pjt@google.com Cc: Venkatesh Pallipadi <venki@google.com> Link: http://lkml.kernel.org/n/tip-kt0trz0apodbf84ucjfdbr1a@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* Merge branch 'for-linus' of ↵Linus Torvalds2012-05-241-5/+2Star
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace Pull user namespace enhancements from Eric Biederman: "This is a course correction for the user namespace, so that we can reach an inexpensive, maintainable, and reasonably complete implementation. Highlights: - Config guards make it impossible to enable the user namespace and code that has not been converted to be user namespace safe. - Use of the new kuid_t type ensures the if you somehow get past the config guards the kernel will encounter type errors if you enable user namespaces and attempt to compile in code whose permission checks have not been updated to be user namespace safe. - All uids from child user namespaces are mapped into the initial user namespace before they are processed. Removing the need to add an additional check to see if the user namespace of the compared uids remains the same. - With the user namespaces compiled out the performance is as good or better than it is today. - For most operations absolutely nothing changes performance or operationally with the user namespace enabled. - The worst case performance I could come up with was timing 1 billion cache cold stat operations with the user namespace code enabled. This went from 156s to 164s on my laptop (or 156ns to 164ns per stat operation). - (uid_t)-1 and (gid_t)-1 are reserved as an internal error value. Most uid/gid setting system calls treat these value specially anyway so attempting to use -1 as a uid would likely cause entertaining failures in userspace. - If setuid is called with a uid that can not be mapped setuid fails. I have looked at sendmail, login, ssh and every other program I could think of that would call setuid and they all check for and handle the case where setuid fails. - If stat or a similar system call is called from a context in which we can not map a uid we lie and return overflowuid. The LFS experience suggests not lying and returning an error code might be better, but the historical precedent with uids is different and I can not think of anything that would break by lying about a uid we can't map. - Capabilities are localized to the current user namespace making it safe to give the initial user in a user namespace all capabilities. My git tree covers all of the modifications needed to convert the core kernel and enough changes to make a system bootable to runlevel 1." Fix up trivial conflicts due to nearby independent changes in fs/stat.c * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (46 commits) userns: Silence silly gcc warning. cred: use correct cred accessor with regards to rcu read lock userns: Convert the move_pages, and migrate_pages permission checks to use uid_eq userns: Convert cgroup permission checks to use uid_eq userns: Convert tmpfs to use kuid and kgid where appropriate userns: Convert sysfs to use kgid/kuid where appropriate userns: Convert sysctl permission checks to use kuid and kgids. userns: Convert proc to use kuid/kgid where appropriate userns: Convert ext4 to user kuid/kgid where appropriate userns: Convert ext3 to use kuid/kgid where appropriate userns: Convert ext2 to use kuid/kgid where appropriate. userns: Convert devpts to use kuid/kgid where appropriate userns: Convert binary formats to use kuid/kgid where appropriate userns: Add negative depends on entries to avoid building code that is userns unsafe userns: signal remove unnecessary map_cred_ns userns: Teach inode_capable to understand inodes whose uids map to other namespaces. userns: Fail exec for suid and sgid binaries with ids outside our user namespace. userns: Convert stat to return values mapped from kuids and kgids userns: Convert user specfied uids and gids in chown into kuids and kgid userns: Use uid_eq gid_eq helpers when comparing kuids and kgids in the vfs ...
| * userns: Convert sched_set_affinity and sched_set_scheduler's permission checksEric W. Biederman2012-05-031-5/+2Star
| | | | | | | | | | | | | | | | | | - Compare kuids with uid_eq - kuid are uniuqe across all user namespaces so there is no longer the need for a user_namespace comparison. Acked-by: Serge Hallyn <serge.hallyn@canonical.com> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
| * userns: Use cred->user_ns instead of cred->user->user_nsEric W. Biederman2012-04-081-1/+1
| | | | | | | | | | | | | | | | | | Optimize performance and prepare for the removal of the user_ns reference from user_struct. Remove the slow long walk through cred->user->user_ns and instead go straight to cred->user_ns. Acked-by: Serge Hallyn <serge.hallyn@canonical.com> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
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*-. \ Merge branches 'perf-urgent-for-linus' and 'perf-core-for-linus' of ↵Linus Torvalds2012-05-231-1/+8
|\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull perf fixes from Ingo Molnar: - Leftover AMD PMU driver fix fix from the end of the v3.4 stabilization cycle. - Late tools/perf/ changes that missed the first round: * endianness fixes * event parsing improvements * libtraceevent fixes factored out from trace-cmd * perl scripting engine fixes related to libtraceevent, * testcase improvements * perf inject / pipe mode fixes * plus a kernel side fix * 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: perf/x86: Update event scheduling constraints for AMD family 15h models * 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: Revert "sched, perf: Use a single callback into the scheduler" perf evlist: Show event attribute details perf tools: Bump default sample freq to 4 kHz perf buildid-list: Work better with pipe mode perf tools: Fix piped mode read code perf inject: Fix broken perf inject -b perf tools: rename HEADER_TRACE_INFO to HEADER_TRACING_DATA perf tools: Add union u64_swap type for swapping u64 data perf tools: Carry perf_event_attr bitfield throught different endians perf record: Fix documentation for branch stack sampling perf target: Add cpu flag to sample_type if target has cpu perf tools: Always try to build libtraceevent perf tools: Rename libparsevent to libtraceevent in Makefile perf script: Rename struct event to struct event_format in perl engine perf script: Explicitly handle known default print arg type perf tools: Add hardcoded name term for pmu events perf tools: Separate 'mem:' event scanner bits perf tools: Use allocated list for each parsed event perf tools: Add support for displaying event parser debug info perf test: Move parse event automated tests to separated object
| | * | Revert "sched, perf: Use a single callback into the scheduler"Jiri Olsa2012-05-231-1/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This reverts commit cb04ff9ac424 ("sched, perf: Use a single callback into the scheduler"). Before this change was introduced, the process switch worked like this (wrt. to perf event schedule): schedule (prev, next) - schedule out all perf events for prev - switch to next - schedule in all perf events for current (next) After the commit, the process switch looks like: schedule (prev, next) - schedule out all perf events for prev - schedule in all perf events for (next) - switch to next The problem is, that after we schedule perf events in, the pmu is enabled and we can receive events even before we make the switch to next - so "current" still being prev process (event SAMPLE data are filled based on the value of the "current" process). Thats exactly what we see for test__PERF_RECORD test. We receive SAMPLES with PID of the process that our tracee is scheduled from. Discussed with Peter Zijlstra: > Bah!, yeah I guess reverting is the right thing for now. Sad > though. > > So by having the two hooks we have a black-spot between them > where we receive no events at all, this black-spot covers the > hand-over of current and we thus don't receive the 'wrong' > events. > > I rather liked we could do away with both that black-spot and > clean up the code a little, but apparently people rely on it. Signed-off-by: Jiri Olsa <jolsa@redhat.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: acme@redhat.com Cc: paulus@samba.org Cc: cjashfor@linux.vnet.ibm.com Cc: fweisbec@gmail.com Cc: eranian@google.com Link: http://lkml.kernel.org/r/20120523111302.GC1638@m.brq.redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | | | Merge branch 'sched-core-for-linus' of ↵Linus Torvalds2012-05-236-608/+352Star
|\ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull scheduler changes from Ingo Molnar: "The biggest change is the cleanup/simplification of the load-balancer: instead of the current practice of architectures twiddling scheduler internal data structures and providing the scheduler domains in colorfully inconsistent ways, we now have generic scheduler code in kernel/sched/core.c:sched_init_numa() that looks at the architecture's node_distance() parameters and (while not fully trusting it) deducts a NUMA topology from it. This inevitably changes balancing behavior - hopefully for the better. There are various smaller optimizations, cleanups and fixlets as well" * 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: sched: Taint kernel with TAINT_WARN after sleep-in-atomic bug sched: Remove stale power aware scheduling remnants and dysfunctional knobs sched/debug: Fix printing large integers on 32-bit platforms sched/fair: Improve the ->group_imb logic sched/nohz: Fix rq->cpu_load[] calculations sched/numa: Don't scale the imbalance sched/fair: Revert sched-domain iteration breakage sched/x86: Rewrite set_cpu_sibling_map() sched/numa: Fix the new NUMA topology bits sched/numa: Rewrite the CONFIG_NUMA sched domain support sched/fair: Propagate 'struct lb_env' usage into find_busiest_group sched/fair: Add some serialization to the sched_domain load-balance walk sched/fair: Let minimally loaded cpu balance the group sched: Change rq->nr_running to unsigned int x86/numa: Check for nonsensical topologies on real hw as well x86/numa: Hard partition cpu topology masks on node boundaries x86/numa: Allow specifying node_distance() for numa=fake x86/sched: Make mwait_usable() heed to "idle=" kernel parameters properly sched: Update documentation and comments sched_rt: Avoid unnecessary dequeue and enqueue of pushable tasks in set_cpus_allowed_rt()
| * | | | sched: Taint kernel with TAINT_WARN after sleep-in-atomic bugKonstantin Khlebnikov2012-05-181-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Usually sleep-in-atomic bugs are followed by dozens other warnings. This patch should help to figure out original source of problem. Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/20120510122004.4873.12726.stgit@zurg Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | | sched: Remove stale power aware scheduling remnants and dysfunctional knobsPeter Zijlstra2012-05-172-367/+2Star
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | It's been broken forever (i.e. it's not scheduling in a power aware fashion), as reported by Suresh and others sending patches, and nobody cares enough to fix it properly ... so remove it to make space free for something better. There's various problems with the code as it stands today, first and foremost the user interface which is bound to topology levels and has multiple values per level. This results in a state explosion which the administrator or distro needs to master and almost nobody does. Furthermore large configuration state spaces aren't good, it means the thing doesn't just work right because it's either under so many impossibe to meet constraints, or even if there's an achievable state workloads have to be aware of it precisely and can never meet it for dynamic workloads. So pushing this kind of decision to user-space was a bad idea even with a single knob - it's exponentially worse with knobs on every node of the topology. There is a proposal to replace the user interface with a single 3 state knob: sched_balance_policy := { performance, power, auto } where 'auto' would be the preferred default which looks at things like Battery/AC mode and possible cpufreq state or whatever the hw exposes to show us power use expectations - but there's been no progress on it in the past many months. Aside from that, the actual implementation of the various knobs is known to be broken. There have been sporadic attempts at fixing things but these always stop short of reaching a mergable state. Therefore this wholesale removal with the hopes of spurring people who care to come forward once again and work on a coherent replacement. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Suresh Siddha <suresh.b.siddha@intel.com> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Vincent Guittot <vincent.guittot@linaro.org> Cc: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/r/1326104915.2442.53.camel@twins Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | | Merge branch 'sched/urgent' into sched/coreIngo Molnar2012-05-171-0/+2
| |\| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Merge reason: bring together all the pending scheduler bits, for the sched/numa changes. Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | | sched/debug: Fix printing large integers on 32-bit platformsPeter Zijlstra2012-05-141-2/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Some numbers like nr_running and nr_uninterruptible are fundamentally unsigned since its impossible to have a negative amount of tasks, yet we still print them as signed to easily recognise the underflow condition. rq->nr_uninterruptible has 'special' accounting and can in fact very easily become negative on a per-cpu basis. It was noted that since the P() macro assumes things are long long and the promotion of unsigned 'int/long' to long long on 32bit doesn't sign extend we print silly large numbers instead of the easier to read signed numbers. Therefore extend the P() macro to not require the sign extention. Reported-by: Diwakar Tundlam <dtundlam@nvidia.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/n/tip-gk5tm8t2n4ix2vkpns42uqqp@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | | sched/fair: Improve the ->group_imb logicPeter Zijlstra2012-05-141-6/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Group imbalance is meant to deal with situations where affinity masks and sched domains don't align well, such as 3 cpus from one group and 6 from another. In this case the domain based balancer will want to put an equal amount of tasks on each side even though they don't have equal cpus. Currently group_imb is set whenever two cpus of a group have a weight difference of at least one avg task and the heaviest cpu has at least two tasks. A group with imbalance set will always be picked as busiest and a balance pass will be forced. The problem is that even if there are no affinity masks this stuff can trigger and cause weird balancing decisions, eg. the observed behaviour was that of 6 cpus, 5 had 2 and 1 had 3 tasks, due to the difference of 1 avg load (they all had the same weight) and nr_running being >1 the group_imbalance logic triggered and did the weird thing of pulling more load instead of trying to move the 1 excess task to the other domain of 6 cpus that had 5 cpu with 2 tasks and 1 cpu with 1 task. Curb the group_imbalance stuff by making the nr_running condition weaker by also tracking the min_nr_running and using the difference in nr_running over the set instead of the absolute max nr_running. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/n/tip-9s7dedozxo8kjsb9kqlrukkf@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
generated by cgit v1.2.3-55-g7522 (git 2.39.0) at 2024-07-04 20:36:25 +0200