- 21 1月, 2013 1 次提交
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由 Rusty Russell 提交于
Fix up all callers as they were before, with make one change: an unsigned module taints the kernel, but doesn't turn off lockdep. Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
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- 11 12月, 2012 5 次提交
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由 Mel Gorman 提交于
The "mm: sched: numa: Control enabling and disabling of NUMA balancing" depends on scheduling debug being enabled but it's perfectly legimate to disable automatic NUMA balancing even without this option. This should take care of it. Signed-off-by: NMel Gorman <mgorman@suse.de>
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由 Mel Gorman 提交于
This patch adds Kconfig options and kernel parameters to allow the enabling and disabling of automatic NUMA balancing. The existance of such a switch was and is very important when debugging problems related to transparent hugepages and we should have the same for automatic NUMA placement. Signed-off-by: NMel Gorman <mgorman@suse.de>
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由 Mel Gorman 提交于
The PTE scanning rate and fault rates are two of the biggest sources of system CPU overhead with automatic NUMA placement. Ideally a proper policy would detect if a workload was properly placed, schedule and adjust the PTE scanning rate accordingly. We do not track the necessary information to do that but we at least know if we migrated or not. This patch scans slower if a page was not migrated as the result of a NUMA hinting fault up to sysctl_numa_balancing_scan_period_max which is now higher than the previous default. Once every minute it will reset the scanner in case of phase changes. This is hilariously crude and the numbers are arbitrary. Workloads will converge quite slowly in comparison to what a proper policy should be able to do. On the plus side, we will chew up less CPU for workloads that have no need for automatic balancing. Signed-off-by: NMel Gorman <mgorman@suse.de>
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由 Peter Zijlstra 提交于
Add a 1 second delay before starting to scan the working set of a task and starting to balance it amongst nodes. [ note that before the constant per task WSS sampling rate patch the initial scan would happen much later still, in effect that patch caused this regression. ] The theory is that short-run tasks benefit very little from NUMA placement: they come and go, and they better stick to the node they were started on. As tasks mature and rebalance to other CPUs and nodes, so does their NUMA placement have to change and so does it start to matter more and more. In practice this change fixes an observable kbuild regression: # [ a perf stat --null --repeat 10 test of ten bzImage builds to /dev/shm ] !NUMA: 45.291088843 seconds time elapsed ( +- 0.40% ) 45.154231752 seconds time elapsed ( +- 0.36% ) +NUMA, no slow start: 46.172308123 seconds time elapsed ( +- 0.30% ) 46.343168745 seconds time elapsed ( +- 0.25% ) +NUMA, 1 sec slow start: 45.224189155 seconds time elapsed ( +- 0.25% ) 45.160866532 seconds time elapsed ( +- 0.17% ) and it also fixes an observable perf bench (hackbench) regression: # perf stat --null --repeat 10 perf bench sched messaging -NUMA: -NUMA: 0.246225691 seconds time elapsed ( +- 1.31% ) +NUMA no slow start: 0.252620063 seconds time elapsed ( +- 1.13% ) +NUMA 1sec delay: 0.248076230 seconds time elapsed ( +- 1.35% ) The implementation is simple and straightforward, most of the patch deals with adding the /proc/sys/kernel/numa_balancing_scan_delay_ms tunable knob. Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Rik van Riel <riel@redhat.com> [ Wrote the changelog, ran measurements, tuned the default. ] Signed-off-by: NIngo Molnar <mingo@kernel.org> Signed-off-by: NMel Gorman <mgorman@suse.de> Reviewed-by: NRik van Riel <riel@redhat.com>
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由 Peter Zijlstra 提交于
NOTE: This patch is based on "sched, numa, mm: Add fault driven placement and migration policy" but as it throws away all the policy to just leave a basic foundation I had to drop the signed-offs-by. This patch creates a bare-bones method for setting PTEs pte_numa in the context of the scheduler that when faulted later will be faulted onto the node the CPU is running on. In itself this does nothing useful but any placement policy will fundamentally depend on receiving hints on placement from fault context and doing something intelligent about it. Signed-off-by: NMel Gorman <mgorman@suse.de> Acked-by: NRik van Riel <riel@redhat.com>
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- 01 12月, 2012 1 次提交
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由 Frederic Weisbecker 提交于
Create a new subsystem that probes on kernel boundaries to keep track of the transitions between level contexts with two basic initial contexts: user or kernel. This is an abstraction of some RCU code that use such tracking to implement its userspace extended quiescent state. We need to pull this up from RCU into this new level of indirection because this tracking is also going to be used to implement an "on demand" generic virtual cputime accounting. A necessary step to shutdown the tick while still accounting the cputime. Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Li Zhong <zhong@linux.vnet.ibm.com> Cc: Gilad Ben-Yossef <gilad@benyossef.com> Reviewed-by: NSteven Rostedt <rostedt@goodmis.org> [ paulmck: fix whitespace error and email address. ] Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
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- 28 11月, 2012 1 次提交
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由 Marcelo Tosatti 提交于
Originally from Jeremy Fitzhardinge. Acked-by: NIngo Molnar <mingo@redhat.com> Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>
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- 20 11月, 2012 2 次提交
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由 Eric W. Biederman 提交于
The task_user_ns function hides the fact that it is getting the user namespace from struct cred on the task. struct cred may go away as soon as the rcu lock is released. This leads to a race where we can dereference a stale user namespace pointer. To make it obvious a struct cred is involved kill task_user_ns. To kill the race modify the users of task_user_ns to only reference the user namespace while the rcu lock is held. Cc: Kees Cook <keescook@chromium.org> Cc: James Morris <james.l.morris@oracle.com> Acked-by: NKees Cook <keescook@chromium.org> Acked-by: NSerge Hallyn <serge.hallyn@canonical.com> Signed-off-by: N"Eric W. Biederman" <ebiederm@xmission.com>
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由 Tejun Heo 提交于
Rename cgroup_subsys css lifetime related callbacks to better describe what their roles are. Also, update documentation. Signed-off-by: NTejun Heo <tj@kernel.org> Acked-by: NLi Zefan <lizefan@huawei.com>
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- 17 11月, 2012 1 次提交
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由 Paul E. McKenney 提交于
When sched_show_task() is invoked from try_to_freeze_tasks(), there is no RCU read-side critical section, resulting in the following splat: [ 125.780730] =============================== [ 125.780766] [ INFO: suspicious RCU usage. ] [ 125.780804] 3.7.0-rc3+ #988 Not tainted [ 125.780838] ------------------------------- [ 125.780875] /home/rafael/src/linux/kernel/sched/core.c:4497 suspicious rcu_dereference_check() usage! [ 125.780946] [ 125.780946] other info that might help us debug this: [ 125.780946] [ 125.781031] [ 125.781031] rcu_scheduler_active = 1, debug_locks = 0 [ 125.781087] 4 locks held by s2ram/4211: [ 125.781120] #0: (&buffer->mutex){+.+.+.}, at: [<ffffffff811e2acf>] sysfs_write_file+0x3f/0x160 [ 125.781233] #1: (s_active#94){.+.+.+}, at: [<ffffffff811e2b58>] sysfs_write_file+0xc8/0x160 [ 125.781339] #2: (pm_mutex){+.+.+.}, at: [<ffffffff81090a81>] pm_suspend+0x81/0x230 [ 125.781439] #3: (tasklist_lock){.?.?..}, at: [<ffffffff8108feed>] try_to_freeze_tasks+0x2cd/0x3f0 [ 125.781543] [ 125.781543] stack backtrace: [ 125.781584] Pid: 4211, comm: s2ram Not tainted 3.7.0-rc3+ #988 [ 125.781632] Call Trace: [ 125.781662] [<ffffffff810a3c73>] lockdep_rcu_suspicious+0x103/0x140 [ 125.781719] [<ffffffff8107cf21>] sched_show_task+0x121/0x180 [ 125.781770] [<ffffffff8108ffb4>] try_to_freeze_tasks+0x394/0x3f0 [ 125.781823] [<ffffffff810903b5>] freeze_kernel_threads+0x25/0x80 [ 125.781876] [<ffffffff81090b65>] pm_suspend+0x165/0x230 [ 125.781924] [<ffffffff8108fa29>] state_store+0x99/0x100 [ 125.781975] [<ffffffff812f5867>] kobj_attr_store+0x17/0x20 [ 125.782038] [<ffffffff811e2b71>] sysfs_write_file+0xe1/0x160 [ 125.782091] [<ffffffff811667a6>] vfs_write+0xc6/0x180 [ 125.782138] [<ffffffff81166ada>] sys_write+0x5a/0xa0 [ 125.782185] [<ffffffff812ff6ae>] ? trace_hardirqs_on_thunk+0x3a/0x3f [ 125.782242] [<ffffffff81669dd2>] system_call_fastpath+0x16/0x1b This commit therefore adds the needed RCU read-side critical section. Reported-by: N"Rafael J. Wysocki" <rjw@sisk.pl> Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
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- 24 10月, 2012 6 次提交
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由 Paul Turner 提交于
While per-entity load-tracking is generally useful, beyond computing shares distribution, e.g. runnable based load-balance (in progress), governors, power-management, etc. These facilities are not yet consumers of this data. This may be trivially reverted when the information is required; but avoid paying the overhead for calculations we will not use until then. Signed-off-by: NPaul Turner <pjt@google.com> Reviewed-by: NBen Segall <bsegall@google.com> Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/20120823141507.422162369@google.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Paul Turner 提交于
Since we are now doing bottom up load accumulation we need explicit notification when a task has been re-parented so that the old hierarchy can be updated. Adds: migrate_task_rq(struct task_struct *p, int next_cpu) (The alternative is to do this out of __set_task_cpu, but it was suggested that this would be a cleaner encapsulation.) Signed-off-by: NPaul Turner <pjt@google.com> Reviewed-by: NBen Segall <bsegall@google.com> Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/20120823141506.660023400@google.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Paul Turner 提交于
We are currently maintaining: runnable_load(cfs_rq) = \Sum task_load(t) For all running children t of cfs_rq. While this can be naturally updated for tasks in a runnable state (as they are scheduled); this does not account for the load contributed by blocked task entities. This can be solved by introducing a separate accounting for blocked load: blocked_load(cfs_rq) = \Sum runnable(b) * weight(b) Obviously we do not want to iterate over all blocked entities to account for their decay, we instead observe that: runnable_load(t) = \Sum p_i*y^i and that to account for an additional idle period we only need to compute: y*runnable_load(t). This means that we can compute all blocked entities at once by evaluating: blocked_load(cfs_rq)` = y * blocked_load(cfs_rq) Finally we maintain a decay counter so that when a sleeping entity re-awakens we can determine how much of its load should be removed from the blocked sum. Signed-off-by: NPaul Turner <pjt@google.com> Reviewed-by: NBen Segall <bsegall@google.com> Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/20120823141506.585389902@google.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Paul Turner 提交于
Instead of tracking averaging the load parented by a cfs_rq, we can track entity load directly. With the load for a given cfs_rq then being the sum of its children. To do this we represent the historical contribution to runnable average within each trailing 1024us of execution as the coefficients of a geometric series. We can express this for a given task t as: runnable_sum(t) = \Sum u_i * y^i, runnable_avg_period(t) = \Sum 1024 * y^i load(t) = weight_t * runnable_sum(t) / runnable_avg_period(t) Where: u_i is the usage in the last i`th 1024us period (approximately 1ms) ~ms and y is chosen such that y^k = 1/2. We currently choose k to be 32 which roughly translates to about a sched period. Signed-off-by: NPaul Turner <pjt@google.com> Reviewed-by: NBen Segall <bsegall@google.com> Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/20120823141506.372695337@google.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Paul E. McKenney 提交于
The RCU CPU stall warnings rely on trigger_all_cpu_backtrace() to do NMI-based dump of the stack traces of all CPUs. Unfortunately, a number of architectures do not implement trigger_all_cpu_backtrace(), in which case RCU falls back to just dumping the stack of the running CPU. This is unhelpful in the case where the running CPU has detected that some other CPU has stalled. This commit therefore makes the running CPU dump the stacks of the tasks running on the stalled CPUs. Signed-off-by: NPaul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
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由 Frederic Weisbecker 提交于
It's only there to call rcu_user_hooks_switch(). Let's just call rcu_user_hooks_switch() directly, we don't need this function in the middle. Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com> Cc: Josh Triplett <josh@joshtriplett.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Richard Weinberger <richard@nod.at> Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
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- 05 10月, 2012 2 次提交
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由 Tang Chen 提交于
Once array sched_domains_numa_masks[] []is defined, it is never updated. When a new cpu on a new node is onlined, the coincident member in sched_domains_numa_masks[][] is not initialized, and all the masks are 0. As a result, the build_overlap_sched_groups() will initialize a NULL sched_group for the new cpu on the new node, which will lead to kernel panic: [ 3189.403280] Call Trace: [ 3189.403286] [<ffffffff8106c36f>] warn_slowpath_common+0x7f/0xc0 [ 3189.403289] [<ffffffff8106c3ca>] warn_slowpath_null+0x1a/0x20 [ 3189.403292] [<ffffffff810b1d57>] build_sched_domains+0x467/0x470 [ 3189.403296] [<ffffffff810b2067>] partition_sched_domains+0x307/0x510 [ 3189.403299] [<ffffffff810b1ea2>] ? partition_sched_domains+0x142/0x510 [ 3189.403305] [<ffffffff810fcc93>] cpuset_update_active_cpus+0x83/0x90 [ 3189.403308] [<ffffffff810b22a8>] cpuset_cpu_active+0x38/0x70 [ 3189.403316] [<ffffffff81674b87>] notifier_call_chain+0x67/0x150 [ 3189.403320] [<ffffffff81664647>] ? native_cpu_up+0x18a/0x1b5 [ 3189.403328] [<ffffffff810a044e>] __raw_notifier_call_chain+0xe/0x10 [ 3189.403333] [<ffffffff81070470>] __cpu_notify+0x20/0x40 [ 3189.403337] [<ffffffff8166663e>] _cpu_up+0xe9/0x131 [ 3189.403340] [<ffffffff81666761>] cpu_up+0xdb/0xee [ 3189.403348] [<ffffffff8165667c>] store_online+0x9c/0xd0 [ 3189.403355] [<ffffffff81437640>] dev_attr_store+0x20/0x30 [ 3189.403361] [<ffffffff8124aa63>] sysfs_write_file+0xa3/0x100 [ 3189.403368] [<ffffffff811ccbe0>] vfs_write+0xd0/0x1a0 [ 3189.403371] [<ffffffff811ccdb4>] sys_write+0x54/0xa0 [ 3189.403375] [<ffffffff81679c69>] system_call_fastpath+0x16/0x1b [ 3189.403377] ---[ end trace 1e6cf85d0859c941 ]--- [ 3189.403398] BUG: unable to handle kernel NULL pointer dereference at 0000000000000018 This patch registers a new notifier for cpu hotplug notify chain, and updates sched_domains_numa_masks every time a new cpu is onlined or offlined. Signed-off-by: NTang Chen <tangchen@cn.fujitsu.com> Signed-off-by: NWen Congyang <wency@cn.fujitsu.com> [ fixed compile warning ] Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1348578751-16904-3-git-send-email-tangchen@cn.fujitsu.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Tang Chen 提交于
We should temporarily reset 'sched_domains_numa_levels' to 0 after it is reset to 'level' in sched_init_numa(). If it fails to allocate memory for array sched_domains_numa_masks[][], the array will contain less then 'level' members. This could be dangerous when we use it to iterate array sched_domains_numa_masks[][] in other functions. This patch set sched_domains_numa_levels to 0 before initializing array sched_domains_numa_masks[][], and reset it to 'level' when sched_domains_numa_masks[][] is fully initialized. Signed-off-by: NTang Chen <tangchen@cn.fujitsu.com> Signed-off-by: NWen Congyang <wency@cn.fujitsu.com> Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1348578751-16904-2-git-send-email-tangchen@cn.fujitsu.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 01 10月, 2012 1 次提交
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由 Al Viro 提交于
Make default just return 0. The current default (checking TIF_POLLING_NRFLAG) is taken to architectures that need it; ones that don't do polling in their idle threads don't need to defined TIF_POLLING_NRFLAG at all. ia64 defined both TS_POLLING (used by its tsk_is_polling()) and TIF_POLLING_NRFLAG (not used at all). Killed the latter... Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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- 26 9月, 2012 3 次提交
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由 Frederic Weisbecker 提交于
When exceptions or irq are about to resume userspace, if the task needs to be rescheduled, the arch low level code calls schedule() directly. If we call it, it is because we have the TIF_RESCHED flag: - It can be set after random local calls to set_need_resched() (RCU, drm, ...) - A wake up happened and the CPU needs preemption. This can happen in several ways: * Remotely: the remote waking CPU has set TIF_RESCHED and send the wakee an IPI to schedule the new task. * Remotely enqueued: the remote waking CPU sends an IPI to the target and the wake up is made by the target. * Locally: waking CPU == wakee CPU and the wakeup is done locally. set_need_resched() is called without IPI. In the case of local and remotely enqueued wake ups, the tick can be restarted when we enqueue the new task and RCU can exit the extended quiescent state at the same time. Then by the time we reach irq exit path and we call schedule, we are not in RCU user mode. But if we call schedule() only because something called set_need_resched(), RCU may still be in user mode when we reach schedule. Also if a wake up is done remotely, the CPU might see the TIF_RESCHED flag and call schedule while the IPI has not yet happen to restart the tick and exit RCU user mode. We need to manually protect against these corner cases. Create a new API schedule_user() that calls schedule() inside rcu_user_exit()-rcu_user_enter() in order to protect it. Archs will need to rely on it now to implement user preemption safely. Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com> Cc: Alessio Igor Bogani <abogani@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Avi Kivity <avi@redhat.com> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Christoph Lameter <cl@linux.com> Cc: Geoff Levand <geoff@infradead.org> Cc: Gilad Ben Yossef <gilad@benyossef.com> Cc: Hakan Akkan <hakanakkan@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Josh Triplett <josh@joshtriplett.org> Cc: Kevin Hilman <khilman@ti.com> Cc: Max Krasnyansky <maxk@qualcomm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephen Hemminger <shemminger@vyatta.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Sven-Thorsten Dietrich <thebigcorporation@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: NJosh Triplett <josh@joshtriplett.org>
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由 Frederic Weisbecker 提交于
When an exception or an irq exits, and we are going to resume into interrupted kernel code, the low level architecture code calls preempt_schedule_irq() if there is a need to reschedule. If the interrupt/exception occured between a call to rcu_user_enter() (from syscall exit, exception exit, do_notify_resume exit, ...) and a real resume to userspace (iret,...), preempt_schedule_irq() can be called whereas RCU thinks we are in userspace. But preempt_schedule_irq() is going to run kernel code and may be some RCU read side critical section. We must exit the userspace extended quiescent state before we call it. To solve this, just call rcu_user_exit() in the beginning of preempt_schedule_irq(). Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com> Cc: Alessio Igor Bogani <abogani@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Avi Kivity <avi@redhat.com> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Christoph Lameter <cl@linux.com> Cc: Geoff Levand <geoff@infradead.org> Cc: Gilad Ben Yossef <gilad@benyossef.com> Cc: Hakan Akkan <hakanakkan@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Josh Triplett <josh@joshtriplett.org> Cc: Kevin Hilman <khilman@ti.com> Cc: Max Krasnyansky <maxk@qualcomm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephen Hemminger <shemminger@vyatta.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Sven-Thorsten Dietrich <thebigcorporation@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: NJosh Triplett <josh@joshtriplett.org>
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由 Frederic Weisbecker 提交于
Clear the syscalls hook of a task when it's scheduled out so that if the task migrates, it doesn't run the syscall slow path on a CPU that might not need it. Also set the syscalls hook on the next task if needed. Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com> Cc: Alessio Igor Bogani <abogani@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Avi Kivity <avi@redhat.com> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Christoph Lameter <cl@linux.com> Cc: Geoff Levand <geoff@infradead.org> Cc: Gilad Ben Yossef <gilad@benyossef.com> Cc: Hakan Akkan <hakanakkan@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Josh Triplett <josh@joshtriplett.org> Cc: Kevin Hilman <khilman@ti.com> Cc: Max Krasnyansky <maxk@qualcomm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephen Hemminger <shemminger@vyatta.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Sven-Thorsten Dietrich <thebigcorporation@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: NJosh Triplett <josh@joshtriplett.org>
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- 25 9月, 2012 1 次提交
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由 Frederic Weisbecker 提交于
Use a naming based on vtime as a prefix for virtual based cputime accounting APIs: - account_system_vtime() -> vtime_account() - account_switch_vtime() -> vtime_task_switch() It makes it easier to allow for further declension such as vtime_account_system(), vtime_account_idle(), ... if we want to find out the context we account to from generic code. This also make it better to know on which subsystem these APIs refer to. Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org>
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- 23 9月, 2012 1 次提交
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由 Peter Zijlstra 提交于
Rabik and Paul reported two different issues related to the same few lines of code. Rabik's issue is that the nr_uninterruptible migration code is wrong in that he sees artifacts due to this (Rabik please do expand in more detail). Paul's issue is that this code as it stands relies on us using stop_machine() for unplug, we all would like to remove this assumption so that eventually we can remove this stop_machine() usage altogether. The only reason we'd have to migrate nr_uninterruptible is so that we could use for_each_online_cpu() loops in favour of for_each_possible_cpu() loops, however since nr_uninterruptible() is the only such loop and its using possible lets not bother at all. The problem Rabik sees is (probably) caused by the fact that by migrating nr_uninterruptible we screw rq->calc_load_active for both rqs involved. So don't bother with fancy migration schemes (meaning we now have to keep using for_each_possible_cpu()) and instead fold any nr_active delta after we migrate all tasks away to make sure we don't have any skewed nr_active accounting. [ paulmck: Move call to calc_load_migration to CPU_DEAD to avoid miscounting noted by Rakib. ] Reported-by: NRakib Mullick <rakib.mullick@gmail.com> Reported-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: NPaul E. McKenney <paul.mckenney@linaro.org>
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- 17 9月, 2012 1 次提交
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由 Linus Torvalds 提交于
This reverts commit 970e1789. Nikolay Ulyanitsky reported thatthe 3.6-rc5 kernel has a 15-20% performance drop on PostgreSQL 9.2 on his machine (running "pgbench"). Borislav Petkov was able to reproduce this, and bisected it to this commit 970e1789 ("sched: Improve scalability via 'CPU buddies' ...") apparently because the new single-idle-buddy model simply doesn't find idle CPU's to reschedule on aggressively enough. Mike Galbraith suspects that it is likely due to the user-mode spinlocks in PostgreSQL not reacting well to preemption, but we don't really know the details - I'll just revert the commit for now. There are hopefully other approaches to improve scheduler scalability without it causing these kinds of downsides. Reported-by: NNikolay Ulyanitsky <lystor@gmail.com> Bisected-by: NBorislav Petkov <bp@alien8.de> Acked-by: NMike Galbraith <efault@gmx.de> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@kernel.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 13 9月, 2012 2 次提交
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由 Peter Zijlstra 提交于
Commit f319da0c ("sched: Fix load avg vs cpu-hotplug") was an incomplete fix: In particular, the problem is that at the point it calls calc_load_migrate() nr_running := 1 (the stopper thread), so move the call to CPU_DEAD where we're sure that nr_running := 0. Also note that we can call calc_load_migrate() without serialization, we know the state of rq is stable since its cpu is dead, and we modify the global state using appropriate atomic ops. Suggested-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1346882630.2600.59.camel@twinsSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Peter Zijlstra 提交于
Now that the last architecture to use this has stopped doing so (ARM, thanks Catalin!) we can remove this complexity from the scheduler core. Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Link: http://lkml.kernel.org/n/tip-g9p2a1w81xxbrze25v9zpzbf@git.kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 04 9月, 2012 4 次提交
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由 Michael Wang 提交于
It's impossible to enter the else branch if we have set skip_clock_update in task_yield_fair(), as yield_to_task_fair() will directly return true after invoke task_yield_fair(). Signed-off-by: NMichael Wang <wangyun@linux.vnet.ibm.com> Acked-by: NMike Galbraith <efault@gmx.de> Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/4FF2925A.9060005@linux.vnet.ibm.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Namhyung Kim 提交于
Various sd->*_idx's are used for refering the rq's load average table when selecting a cpu to run. However they can be set to any number with sysctl knobs so that it can crash the kernel if something bad is given. Fix it by limiting them into the actual range. Signed-off-by: NNamhyung Kim <namhyung@kernel.org> Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1345104204-8317-1-git-send-email-namhyung@kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Peter Boonstoppel 提交于
migrate_tasks() uses _pick_next_task_rt() to get tasks from the real-time runqueues to be migrated. When rt_rq is throttled _pick_next_task_rt() won't return anything, in which case migrate_tasks() can't move all threads over and gets stuck in an infinite loop. Instead unthrottle rt runqueues before migrating tasks. Additionally: move unthrottle_offline_cfs_rqs() to rq_offline_fair() Signed-off-by: NPeter Boonstoppel <pboonstoppel@nvidia.com> Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Cc: Paul Turner <pjt@google.com> Link: http://lkml.kernel.org/r/5FBF8E85CA34454794F0F7ECBA79798F379D3648B7@HQMAIL04.nvidia.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Peter Zijlstra 提交于
Rabik and Paul reported two different issues related to the same few lines of code. Rabik's issue is that the nr_uninterruptible migration code is wrong in that he sees artifacts due to this (Rabik please do expand in more detail). Paul's issue is that this code as it stands relies on us using stop_machine() for unplug, we all would like to remove this assumption so that eventually we can remove this stop_machine() usage altogether. The only reason we'd have to migrate nr_uninterruptible is so that we could use for_each_online_cpu() loops in favour of for_each_possible_cpu() loops, however since nr_uninterruptible() is the only such loop and its using possible lets not bother at all. The problem Rabik sees is (probably) caused by the fact that by migrating nr_uninterruptible we screw rq->calc_load_active for both rqs involved. So don't bother with fancy migration schemes (meaning we now have to keep using for_each_possible_cpu()) and instead fold any nr_active delta after we migrate all tasks away to make sure we don't have any skewed nr_active accounting. Reported-by: NRakib Mullick <rakib.mullick@gmail.com> Reported-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1345454817.23018.27.camel@twinsSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 20 8月, 2012 2 次提交
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由 Frederic Weisbecker 提交于
The archs that implement virtual cputime accounting all flush the cputime of a task when it gets descheduled and sometimes set up some ground initialization for the next task to account its cputime. These archs all put their own hooks in their context switch callbacks and handle the off-case themselves. Consolidate this by creating a new account_switch_vtime() callback called in generic code right after a context switch and that these archs must implement to flush the prev task cputime and initialize the next task cputime related state. Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com> Acked-by: NMartin Schwidefsky <schwidefsky@de.ibm.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org>
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由 Frederic Weisbecker 提交于
Extract cputime code from the giant sched/core.c and put it in its own file. This make it easier to deal with this particular area and de-bloat a bit more core.c Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com> Acked-by: NMartin Schwidefsky <schwidefsky@de.ibm.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org>
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- 14 8月, 2012 4 次提交
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由 Alex Shi 提交于
Since power saving code was removed from sched now, the implement code is out of service in this function, and even pollute other logical. like, 'want_sd' never has chance to be set '0', that remove the effect of SD_WAKE_AFFINE here. So, clean up the obsolete code, includes SD_PREFER_LOCAL. Signed-off-by: NAlex Shi <alex.shi@intel.com> Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/5028F431.6000306@intel.comSigned-off-by: NThomas Gleixner <tglx@linutronix.de>
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由 Pekka Enberg 提交于
This patch adds a comment on top of the schedule() function to explain to scheduler newbies how the main scheduler function is entered. Acked-by: NRandy Dunlap <rdunlap@xenotime.net> Explained-by: NIngo Molnar <mingo@kernel.org> Explained-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: NPekka Enberg <penberg@kernel.org> Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1344070187-2420-1-git-send-email-penberg@kernel.orgSigned-off-by: NThomas Gleixner <tglx@linutronix.de>
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由 Mike Galbraith 提交于
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: NMike Galbraith <efault@gmx.de> Cc: stable@kernel.org # v3.3+ Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1344308413.6846.7.camel@marge.simpson.netSigned-off-by: NThomas Gleixner <tglx@linutronix.de>
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由 Stanislaw Gruszka 提交于
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: NStanislaw Gruszka <sgruszka@redhat.com> Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/20120808092714.GA3580@redhat.comSigned-off-by: NThomas Gleixner <tglx@linutronix.de>
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- 26 7月, 2012 2 次提交
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由 Andrew Vagin 提交于
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: NAndrew Vagin <avagin@openvz.org> Signed-off-by: NPeter 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.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Namhyung Kim 提交于
It seems there's no specific reason to open-code it. I guess commit 0122ec5b ("sched: Add p->pi_lock to task_rq_lock()") simply missed it. Let's be consistent with others. Signed-off-by: NNamhyung Kim <namhyung@kernel.org> Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1341647342-6742-1-git-send-email-namhyung@kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>
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