- Oct 05, 2021
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Ricardo Neri authored
Before deciding to pull tasks when using asymmetric packing of tasks, on some architectures (e.g., x86) it is necessary to know not only the state of dst_cpu but also of its SMT siblings. The decision to classify a candidate busiest group as group_asym_packing is done in update_sg_lb_stats(). Give this function access to the scheduling domain statistics, which contains the statistics of the local group. Originally-by:
Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by:
Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Signed-off-by:
Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by:
Joel Fernandes (Google) <joel@joelfernandes.org> Reviewed-by:
Len Brown <len.brown@intel.com> Reviewed-by:
Vincent Guittot <vincent.guittot@linaro.org> Link: https://lkml.kernel.org/r/20210911011819.12184-5-ricardo.neri-calderon@linux.intel.com
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Ricardo Neri authored
sched_asmy_prefer() always returns false when called on the local group. By checking local_group, we can avoid additional checks and invoking sched_asmy_prefer() when it is not needed. No functional changes are introduced. Signed-off-by:
Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Signed-off-by:
Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by:
Joel Fernandes (Google) <joel@joelfernandes.org> Reviewed-by:
Len Brown <len.brown@intel.com> Reviewed-by:
Vincent Guittot <vincent.guittot@linaro.org> Link: https://lkml.kernel.org/r/20210911011819.12184-4-ricardo.neri-calderon@linux.intel.com
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Ricardo Neri authored
There exist situations in which the load balance needs to know the properties of the CPUs in a scheduling group. When using asymmetric packing, for instance, the load balancer needs to know not only the state of dst_cpu but also of its SMT siblings, if any. Use the flags of the child scheduling domains to initialize scheduling group flags. This will reflect the properties of the CPUs in the group. A subsequent changeset will make use of these new flags. No functional changes are introduced. Originally-by:
Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by:
Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Signed-off-by:
Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by:
Joel Fernandes (Google) <joel@joelfernandes.org> Reviewed-by:
Len Brown <len.brown@intel.com> Reviewed-by:
Vincent Guittot <vincent.guittot@linaro.org> Link: https://lkml.kernel.org/r/20210911011819.12184-3-ricardo.neri-calderon@linux.intel.com
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Ricardo Neri authored
When scheduling, it is better to prefer a separate physical core rather than the SMT sibling of a high priority core. The existing formula to compute priorities takes such fact in consideration. There may exist, however, combinations of priorities (i.e., maximum frequencies) in which the priority of high-numbered SMT siblings of high-priority cores collides with the priority of low-numbered SMT siblings of low-priority cores. Consider for instance an SMT2 system with CPUs [0, 1] with priority 60 and [2, 3] with priority 30(CPUs in brackets are SMT siblings. In such a case, the resulting priorities would be [120, 60], [60, 30]. Thus, to ensure that CPU2 has higher priority than CPU1, divide the raw priority by the squared SMT iterator. The resulting priorities are [120, 30]. [60, 15]. Originally-by:
Len Brown <len.brown@intel.com> Signed-off-by:
Len Brown <len.brown@intel.com> Signed-off-by:
Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Signed-off-by:
Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20210911011819.12184-2-ricardo.neri-calderon@linux.intel.com
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Sebastian Andrzej Siewior authored
With enabled threaded interrupts the nouveau driver reported the following: | Chain exists of: | &mm->mmap_lock#2 --> &device->mutex --> &cpuset_rwsem | | Possible unsafe locking scenario: | | CPU0 CPU1 | ---- ---- | lock(&cpuset_rwsem); | lock(&device->mutex); | lock(&cpuset_rwsem); | lock(&mm->mmap_lock#2); The device->mutex is nvkm_device::mutex. Unblocking the lockchain at `cpuset_rwsem' is probably the easiest thing to do. Move the priority reset to the start of the newly created thread. Fixes: 710da3c8 ("sched/core: Prevent race condition between cpuset and __sched_setscheduler()") Reported-by:
Mike Galbraith <efault@gmx.de> Signed-off-by:
Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by:
Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/a23a826af7c108ea5651e73b8fbae5e653f16e86.camel@gmx.de
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Frederic Weisbecker authored
Currently the boot defined preempt behaviour (aka dynamic preempt) selects full preemption by default when the "preempt=" boot parameter is omitted. However distros may rather want to default to either no preemption or voluntary preemption. To provide with this flexibility, make dynamic preemption a visible Kconfig option and adapt the preemption behaviour selected by the user to either static or dynamic preemption. Signed-off-by:
Frederic Weisbecker <frederic@kernel.org> Signed-off-by:
Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20210914103134.11309-1-frederic@kernel.org
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YueHaibing authored
These is no caller in tree since commit 523e979d ("sched/core: Use PELT for scale_rt_capacity()") Signed-off-by:
YueHaibing <yuehaibing@huawei.com> Signed-off-by:
Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20210914095244.52780-1-yuehaibing@huawei.com
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Yafang Shao authored
After we make the struct sched_statistics and the helpers of it independent of fair sched class, we can easily use the schedstats facility for deadline sched class. The schedstat usage in DL sched class is similar with fair sched class, for example, fair deadline enqueue update_stats_enqueue_fair update_stats_enqueue_dl dequeue update_stats_dequeue_fair update_stats_dequeue_dl put_prev_task update_stats_wait_start update_stats_wait_start_dl set_next_task update_stats_wait_end update_stats_wait_end_dl The user can get the schedstats information in the same way in fair sched class. For example, fair deadline /proc/[pid]/sched /proc/[pid]/sched The output of a deadline task's schedstats as follows, $ cat /proc/69662/sched ... se.sum_exec_runtime : 3067.696449 se.nr_migrations : 0 sum_sleep_runtime : 720144.029661 sum_block_runtime : 0.547853 wait_start : 0.000000 sleep_start : 14131540.828955 block_start : 0.000000 sleep_max : 2999.974045 block_max : 0.283637 exec_max : 1.000269 slice_max : 0.000000 wait_max : 0.002217 wait_sum : 0.762179 wait_count : 733 iowait_sum : 0.547853 iowait_count : 3 nr_migrations_cold : 0 nr_failed_migrations_affine : 0 nr_failed_migrations_running : 0 nr_failed_migrations_hot : 0 nr_forced_migrations : 0 nr_wakeups : 246 nr_wakeups_sync : 2 nr_wakeups_migrate : 0 nr_wakeups_local : 244 nr_wakeups_remote : 2 nr_wakeups_affine : 0 nr_wakeups_affine_attempts : 0 nr_wakeups_passive : 0 nr_wakeups_idle : 0 ... The sched:sched_stat_{wait, sleep, iowait, blocked} tracepoints can be used to trace deadlline tasks as well. Signed-off-by:
Yafang Shao <laoar.shao@gmail.com> Signed-off-by:
Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20210905143547.4668-9-laoar.shao@gmail.com
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Yafang Shao authored
The runtime of a DL task has already been there, so we only need to add a tracepoint. One difference between fair task and DL task is that there is no vruntime in dl task. To reuse the sched_stat_runtime tracepoint, '0' is passed as vruntime for DL task. The output of this tracepoint for DL task as follows, top-36462 [047] d.h. 6083.452103: sched_stat_runtime: comm=top pid=36462 runtime=409898 [ns] vruntime=0 [ns] Signed-off-by:
Yafang Shao <laoar.shao@gmail.com> Signed-off-by:
Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20210905143547.4668-8-laoar.shao@gmail.com
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Yafang Shao authored
We want to measure the latency of RT tasks in our production environment with schedstats facility, but currently schedstats is only supported for fair sched class. This patch enable it for RT sched class as well. After we make the struct sched_statistics and the helpers of it independent of fair sched class, we can easily use the schedstats facility for RT sched class. The schedstat usage in RT sched class is similar with fair sched class, for example, fair RT enqueue update_stats_enqueue_fair update_stats_enqueue_rt dequeue update_stats_dequeue_fair update_stats_dequeue_rt put_prev_task update_stats_wait_start update_stats_wait_start_rt set_next_task update_stats_wait_end update_stats_wait_end_rt The user can get the schedstats information in the same way in fair sched class. For example, fair RT /proc/[pid]/sched /proc/[pid]/sched schedstats is not supported for RT group. The output of a RT task's schedstats as follows, $ cat /proc/10349/sched ... sum_sleep_runtime : 972.434535 sum_block_runtime : 960.433522 wait_start : 188510.871584 sleep_start : 0.000000 block_start : 0.000000 sleep_max : 12.001013 block_max : 952.660622 exec_max : 0.049629 slice_max : 0.000000 wait_max : 0.018538 wait_sum : 0.424340 wait_count : 49 iowait_sum : 956.495640 iowait_count : 24 nr_migrations_cold : 0 nr_failed_migrations_affine : 0 nr_failed_migrations_running : 0 nr_failed_migrations_hot : 0 nr_forced_migrations : 0 nr_wakeups : 49 nr_wakeups_sync : 0 nr_wakeups_migrate : 0 nr_wakeups_local : 49 nr_wakeups_remote : 0 nr_wakeups_affine : 0 nr_wakeups_affine_attempts : 0 nr_wakeups_passive : 0 nr_wakeups_idle : 0 ... The sched:sched_stat_{wait, sleep, iowait, blocked} tracepoints can be used to trace RT tasks as well. The output of these tracepoints for a RT tasks as follows, - runtime stress-10352 [004] d.h. 1035.382286: sched_stat_runtime: comm=stress pid=10352 runtime=995769 [ns] vruntime=0 [ns] [vruntime=0 means it is a RT task] - wait <idle>-0 [004] dN.. 1227.688544: sched_stat_wait: comm=stress pid=10352 delay=46849882 [ns] - blocked kworker/4:1-465 [004] dN.. 1585.676371: sched_stat_blocked: comm=stress pid=17194 delay=189963 [ns] - iowait kworker/4:1-465 [004] dN.. 1585.675330: sched_stat_iowait: comm=stress pid=17189 delay=182848 [ns] - sleep sleep-18194 [023] dN.. 1780.891840: sched_stat_sleep: comm=sleep.sh pid=17767 delay=1001160770 [ns] sleep-18196 [023] dN.. 1781.893208: sched_stat_sleep: comm=sleep.sh pid=17767 delay=1001161970 [ns] sleep-18197 [023] dN.. 1782.894544: sched_stat_sleep: comm=sleep.sh pid=17767 delay=1001128840 [ns] [ In sleep.sh, it sleeps 1 sec each time. ] [lkp@intel.com: reported build failure in earlier version] Signed-off-by:
Yafang Shao <laoar.shao@gmail.com> Signed-off-by:
Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20210905143547.4668-7-laoar.shao@gmail.com
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Yafang Shao authored
The runtime of a RT task has already been there, so we only need to add a tracepoint. One difference between fair task and RT task is that there is no vruntime in RT task. To reuse the sched_stat_runtime tracepoint, '0' is passed as vruntime for RT task. The output of this tracepoint for RT task as follows, stress-9748 [039] d.h. 113.519352: sched_stat_runtime: comm=stress pid=9748 runtime=997573 [ns] vruntime=0 [ns] stress-9748 [039] d.h. 113.520352: sched_stat_runtime: comm=stress pid=9748 runtime=997627 [ns] vruntime=0 [ns] stress-9748 [039] d.h. 113.521352: sched_stat_runtime: comm=stress pid=9748 runtime=998203 [ns] vruntime=0 [ns] Signed-off-by:
Yafang Shao <laoar.shao@gmail.com> Signed-off-by:
Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20210905143547.4668-6-laoar.shao@gmail.com
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Yafang Shao authored
Currently in schedstats we have sum_sleep_runtime and iowait_sum, but there's no metric to show how long the task is in D state. Once a task in D state, it means the task is blocked in the kernel, for example the task may be waiting for a mutex. The D state is more frequent than iowait, and it is more critital than S state. So it is worth to add a metric to measure it. Signed-off-by:
Yafang Shao <laoar.shao@gmail.com> Signed-off-by:
Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20210905143547.4668-5-laoar.shao@gmail.com
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Yafang Shao authored
The original prototype of the schedstats helpers are update_stats_wait_*(struct cfs_rq *cfs_rq, struct sched_entity *se) The cfs_rq in these helpers is used to get the rq_clock, and the se is used to get the struct sched_statistics and the struct task_struct. In order to make these helpers available by all sched classes, we can pass the rq, sched_statistics and task_struct directly. Then the new helpers are update_stats_wait_*(struct rq *rq, struct task_struct *p, struct sched_statistics *stats) which are independent of fair sched class. To avoid vmlinux growing too large or introducing ovehead when !schedstat_enabled(), some new helpers after schedstat_enabled() are also introduced, Suggested by Mel. These helpers are in sched/stats.c, __update_stats_wait_*(struct rq *rq, struct task_struct *p, struct sched_statistics *stats) The size of vmlinux as follows, Before After Size of vmlinux 826308552 826304640 The size is a litte smaller as some functions are not inlined again after the change. I also compared the sched performance with 'perf bench sched pipe', suggested by Mel. The result as followsi (in usecs/op), Before After kernel.sched_schedstats=0 5.2~5.4 5.2~5.4 kernel.sched_schedstats=1 5.3~5.5 5.3~5.5 [These data is a little difference with the prev version, that is because my old test machine is destroyed so I have to use a new different test machine.] Almost no difference. No functional change. [lkp@intel.com: reported build failure in prev version] Signed-off-by:
Yafang Shao <laoar.shao@gmail.com> Signed-off-by:
Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by:
Mel Gorman <mgorman@suse.de> Link: https://lore.kernel.org/r/20210905143547.4668-4-laoar.shao@gmail.com
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Yafang Shao authored
If we want to use the schedstats facility to trace other sched classes, we should make it independent of fair sched class. The struct sched_statistics is the schedular statistics of a task_struct or a task_group. So we can move it into struct task_struct and struct task_group to achieve the goal. After the patch, schestats are orgnized as follows, struct task_struct { ... struct sched_entity se; struct sched_rt_entity rt; struct sched_dl_entity dl; ... struct sched_statistics stats; ... }; Regarding the task group, schedstats is only supported for fair group sched, and a new struct sched_entity_stats is introduced, suggested by Peter - struct sched_entity_stats { struct sched_entity se; struct sched_statistics stats; } __no_randomize_layout; Then with the se in a task_group, we can easily get the stats. The sched_statistics members may be frequently modified when schedstats is enabled, in order to avoid impacting on random data which may in the same cacheline with them, the struct sched_statistics is defined as cacheline aligned. As this patch changes the core struct of scheduler, so I verified the performance it may impact on the scheduler with 'perf bench sched pipe', suggested by Mel. Below is the result, in which all the values are in usecs/op. Before After kernel.sched_schedstats=0 5.2~5.4 5.2~5.4 kernel.sched_schedstats=1 5.3~5.5 5.3~5.5 [These data is a little difference with the earlier version, that is because my old test machine is destroyed so I have to use a new different test machine.] Almost no impact on the sched performance. No functional change. [lkp@intel.com: reported build failure in earlier version] Signed-off-by:
Yafang Shao <laoar.shao@gmail.com> Signed-off-by:
Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by:
Mel Gorman <mgorman@suse.de> Link: https://lore.kernel.org/r/20210905143547.4668-3-laoar.shao@gmail.com
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Yafang Shao authored
schedstat_enabled() has been already checked, so we can use __schedstat_set() directly. Signed-off-by:
Yafang Shao <laoar.shao@gmail.com> Signed-off-by:
Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by:
Mel Gorman <mgorman@suse.de> Link: https://lore.kernel.org/r/20210905143547.4668-2-laoar.shao@gmail.com
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Li Zhijian authored
Previously, 'make -C sched run_tests' will block forever when it occurs something wrong where the *selftests framework* is waiting for its child processes to exit. [root@iaas-rpma sched]# ./cs_prctl_test ## Create a thread/process/process group hiearchy Not a core sched system tid=74985, / tgid=74985 / pgid=74985: ffffffffffffffff Not a core sched system tid=74986, / tgid=74986 / pgid=74985: ffffffffffffffff Not a core sched system tid=74988, / tgid=74986 / pgid=74985: ffffffffffffffff Not a core sched system tid=74989, / tgid=74986 / pgid=74985: ffffffffffffffff Not a core sched system tid=74990, / tgid=74986 / pgid=74985: ffffffffffffffff Not a core sched system tid=74987, / tgid=74987 / pgid=74985: ffffffffffffffff Not a core sched system tid=74991, / tgid=74987 / pgid=74985: ffffffffffffffff Not a core sched system tid=74992, / tgid=74987 / pgid=74985: ffffffffffffffff Not a core sched system tid=74993, / tgid=74987 / pgid=74985: ffffffffffffffff Not a core sched system (268) FAILED: get_cs_cookie(0) == 0 ## Set a cookie on entire process group -1 = prctl(62, 1, 0, 2, 0) core_sched create failed -- PGID: Invalid argument (cs_prctl_test.c:272) - [root@iaas-rpma sched]# ps PID TTY TIME CMD 4605 pts/2 00:00:00 bash 74986 pts/2 00:00:00 cs_prctl_test 74987 pts/2 00:00:00 cs_prctl_test 74999 pts/2 00:00:00 ps Reported-by:
kernel test robot <lkp@intel.com> Signed-off-by:
Li Zhijian <lizhijian@cn.fujitsu.com> Signed-off-by:
Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by:
Chris Hyser <chris.hyser@oracle.com> Link: https://lore.kernel.org/r/20210902024333.75983-1-lizhijian@cn.fujitsu.com
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Huaixin Chang authored
Basic description of usage and effect for CFS Bandwidth Control Burst. Co-developed-by:
Shanpei Chen <shanpeic@linux.alibaba.com> Signed-off-by:
Shanpei Chen <shanpeic@linux.alibaba.com> Co-developed-by:
Tianchen Ding <dtcccc@linux.alibaba.com> Signed-off-by:
Tianchen Ding <dtcccc@linux.alibaba.com> Signed-off-by:
Huaixin Chang <changhuaixin@linux.alibaba.com> Signed-off-by:
Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by:
Daniel Jordan <daniel.m.jordan@oracle.com> Acked-by:
Tejun Heo <tj@kernel.org> Link: https://lore.kernel.org/r/20210830032215.16302-3-changhuaixin@linux.alibaba.com
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Huaixin Chang authored
Two new statistics are introduced to show the internal of burst feature and explain why burst helps or not. nr_bursts: number of periods bandwidth burst occurs burst_time: cumulative wall-time (in nanoseconds) that any cpus has used above quota in respective periods Co-developed-by:
Shanpei Chen <shanpeic@linux.alibaba.com> Signed-off-by:
Shanpei Chen <shanpeic@linux.alibaba.com> Co-developed-by:
Tianchen Ding <dtcccc@linux.alibaba.com> Signed-off-by:
Tianchen Ding <dtcccc@linux.alibaba.com> Signed-off-by:
Huaixin Chang <changhuaixin@linux.alibaba.com> Signed-off-by:
Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by:
Daniel Jordan <daniel.m.jordan@oracle.com> Acked-by:
Tejun Heo <tj@kernel.org> Link: https://lore.kernel.org/r/20210830032215.16302-2-changhuaixin@linux.alibaba.com
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Josh Don authored
Give reduced sleeper credit to SCHED_IDLE entities. As a result, woken SCHED_IDLE entities will take longer to preempt normal entities. The benefit of this change is to make it less likely that a newly woken SCHED_IDLE entity will preempt a short-running normal entity before it blocks. We still give a small sleeper credit to SCHED_IDLE entities, so that idle<->idle competition retains some fairness. Example: With HZ=1000, spawned four threads affined to one cpu, one of which was set to SCHED_IDLE. Without this patch, wakeup latency for the SCHED_IDLE thread was ~1-2ms, with the patch the wakeup latency was ~5ms. Signed-off-by:
Josh Don <joshdon@google.com> Signed-off-by:
Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by:
Vincent Guittot <vincent.guittot@linaro.org> Reviewed-by:
Jiang Biao <benbjiang@tencent.com> Link: https://lore.kernel.org/r/20210820010403.946838-5-joshdon@google.com
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Josh Don authored
Use a small, non-scaled min granularity for SCHED_IDLE entities, when competing with normal entities. This reduces the latency of getting a normal entity back on cpu, at the expense of increased context switch frequency of SCHED_IDLE entities. The benefit of this change is to reduce the round-robin latency for normal entities when competing with a SCHED_IDLE entity. Example: on a machine with HZ=1000, spawned two threads, one of which is SCHED_IDLE, and affined to one cpu. Without this patch, the SCHED_IDLE thread runs for 4ms then waits for 1.4s. With this patch, it runs for 1ms and waits 340ms (as it round-robins with the other thread). Signed-off-by:
Josh Don <joshdon@google.com> Signed-off-by:
Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by:
Vincent Guittot <vincent.guittot@linaro.org> Link: https://lore.kernel.org/r/20210820010403.946838-4-joshdon@google.com
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Josh Don authored
Adds cfs_rq->idle_nr_running, which accounts the number of idle entities directly enqueued on the cfs_rq. Signed-off-by:
Josh Don <joshdon@google.com> Signed-off-by:
Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by:
Vincent Guittot <vincent.guittot@linaro.org> Link: https://lore.kernel.org/r/20210820010403.946838-3-joshdon@google.com
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Josh Don authored
/proc/uptime reports idle time by reading the CPUTIME_IDLE field from the per-cpu kcpustats. However, on NO_HZ systems, idle time is not continually updated on idle cpus, leading this value to appear incorrectly small. /proc/stat performs an accounting update when reading idle time; we can use the same approach for uptime. With this patch, /proc/stat and /proc/uptime now agree on idle time. Additionally, the following shows idle time tick up consistently on an idle machine: (while true; do cat /proc/uptime; sleep 1; done) | awk '{print $2-prev; prev=$2}' Reported-by:
Luigi Rizzo <lrizzo@google.com> Signed-off-by:
Josh Don <joshdon@google.com> Signed-off-by:
Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by:
Eric Dumazet <edumazet@google.com> Link: https://lkml.kernel.org/r/20210827165438.3280779-1-joshdon@google.com
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Peter Zijlstra authored
Tao suggested a two-pass task selection to avoid the retry loop. Not only does it avoid the retry loop, it results in *much* simpler code. This also fixes an issue spotted by Josh Don where, for SMT3+, we can forget to update max on the first pass and get to do an extra round. Suggested-by:
Tao Zhou <tao.zhou@linux.dev> Signed-off-by:
Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by:
Josh Don <joshdon@google.com> Reviewed-by:
Vineeth Pillai (Microsoft) <vineethrp@gmail.com> Link: https://lkml.kernel.org/r/YSS9+k1teA9oPEKl@hirez.programming.kicks-ass.net
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Sebastian Andrzej Siewior authored
With PREEMPT_RT enabled all hrtimers callbacks will be invoked in softirq mode unless they are explicitly marked as HRTIMER_MODE_HARD. During boot kthread_bind() is used for the creation of per-CPU threads and then hangs in wait_task_inactive() if the ksoftirqd is not yet up and running. The hang disappeared since commit 26c7295b ("kthread: Do not preempt current task if it is going to call schedule()") but enabling function trace on boot reliably leads to the freeze on boot behaviour again. The timer in wait_task_inactive() can not be directly used by a user interface to abuse it and create a mass wake up of several tasks at the same time leading to long sections with disabled interrupts. Therefore it is safe to make the timer HRTIMER_MODE_REL_HARD. Switch the timer to HRTIMER_MODE_REL_HARD. Signed-off-by:
Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by:
Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20210826170408.vm7rlj7odslshwch@linutronix.de
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Valentin Schneider authored
Consider a system with some NOHZ-idle CPUs, such that nohz.idle_cpus_mask = S nohz.next_balance = T When a new CPU k goes NOHZ idle (nohz_balance_enter_idle()), we end up with: nohz.idle_cpus_mask = S \U {k} nohz.next_balance = T Note that the nohz.next_balance hasn't changed - it won't be updated until a NOHZ balance is triggered. This is problematic if the newly NOHZ idle CPU has an earlier rq.next_balance than the other NOHZ idle CPUs, IOW if: cpu_rq(k).next_balance < nohz.next_balance In such scenarios, the existing nohz.next_balance will prevent any NOHZ balance from happening, which itself will prevent nohz.next_balance from being updated to this new cpu_rq(k).next_balance. Unnecessary load balance delays of over 12ms caused by this were observed on an arm64 RB5 board. Use the new nohz.needs_update flag to mark the presence of newly-idle CPUs that need their rq->next_balance to be collated into nohz.next_balance. Trigger a NOHZ_NEXT_KICK when the flag is set. Signed-off-by:
Valentin Schneider <valentin.schneider@arm.com> Signed-off-by:
Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by:
Vincent Guittot <vincent.guittot@linaro.org> Link: https://lkml.kernel.org/r/20210823111700.2842997-3-valentin.schneider@arm.com
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Valentin Schneider authored
A following patch will trigger NOHZ idle balances as a means to update nohz.next_balance. Vincent noted that blocked load updates can have non-negligible overhead, which should be avoided if the intent is to only update nohz.next_balance. Add a new NOHZ balance kick flag, NOHZ_NEXT_KICK. Gate NOHZ blocked load update by the presence of NOHZ_STATS_KICK - currently all NOHZ balance kicks will have the NOHZ_STATS_KICK flag set, so no change in behaviour is expected. Suggested-by:
Vincent Guittot <vincent.guittot@linaro.org> Signed-off-by:
Valentin Schneider <valentin.schneider@arm.com> Signed-off-by:
Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by:
Vincent Guittot <vincent.guittot@linaro.org> Link: https://lkml.kernel.org/r/20210823111700.2842997-2-valentin.schneider@arm.com
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- Oct 04, 2021
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Linus Torvalds authored
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Chen Jingwen authored
In commit b212921b ("elf: don't use MAP_FIXED_NOREPLACE for elf executable mappings") we still leave MAP_FIXED_NOREPLACE in place for load_elf_interp. Unfortunately, this will cause kernel to fail to start with: 1 (init): Uhuuh, elf segment at 00003ffff7ffd000 requested but the memory is mapped already Failed to execute /init (error -17) The reason is that the elf interpreter (ld.so) has overlapping segments. readelf -l ld-2.31.so Program Headers: Type Offset VirtAddr PhysAddr FileSiz MemSiz Flags Align LOAD 0x0000000000000000 0x0000000000000000 0x0000000000000000 0x000000000002c94c 0x000000000002c94c R E 0x10000 LOAD 0x000000000002dae0 0x000000000003dae0 0x000000000003dae0 0x00000000000021e8 0x0000000000002320 RW 0x10000 LOAD 0x000000000002fe00 0x000000000003fe00 0x000000000003fe00 0x00000000000011ac 0x0000000000001328 RW 0x10000 The reason for this problem is the same as described in commit ad55eac7 ("elf: enforce MAP_FIXED on overlaying elf segments"). Not only executable binaries, elf interpreters (e.g. ld.so) can have overlapping elf segments, so we better drop MAP_FIXED_NOREPLACE and go back to MAP_FIXED in load_elf_interp. Fixes: 4ed28639 ("fs, elf: drop MAP_FIXED usage from elf_map") Cc: <stable@vger.kernel.org> # v4.19 Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Michal Hocko <mhocko@suse.com> Signed-off-by:
Chen Jingwen <chenjingwen6@huawei.com> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4Linus Torvalds authored
Pull ext4 fixes from Ted Ts'o: "Fix a number of ext4 bugs in fast_commit, inline data, and delayed allocation. Also fix error handling code paths in ext4_dx_readdir() and ext4_fill_super(). Finally, avoid a grabbing a journal head in the delayed allocation write in the common cases where we are overwriting a pre-existing block or appending to an inode" * tag 'ext4_for_linus_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: ext4: recheck buffer uptodate bit under buffer lock ext4: fix potential infinite loop in ext4_dx_readdir() ext4: flush s_error_work before journal destroy in ext4_fill_super ext4: fix loff_t overflow in ext4_max_bitmap_size() ext4: fix reserved space counter leakage ext4: limit the number of blocks in one ADD_RANGE TLV ext4: enforce buffer head state assertion in ext4_da_map_blocks ext4: remove extent cache entries when truncating inline data ext4: drop unnecessary journal handle in delalloc write ext4: factor out write end code of inline file ext4: correct the error path of ext4_write_inline_data_end() ext4: check and update i_disksize properly ext4: add error checking to ext4_ext_replay_set_iblocks()
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Linus Torvalds authored
The objtool warning that the kvm instruction emulation code triggered wasn't very useful: arch/x86/kvm/emulate.o: warning: objtool: __ex_table+0x4: don't know how to handle reloc symbol type: kvm_fastop_exception in that it helpfully tells you which symbol name it had trouble figuring out the relocation for, but it doesn't actually say what the unknown symbol type was that triggered it all. In this case it was because of missing type information (type 0, aka STT_NOTYPE), but on the whole it really should just have printed that out as part of the message. Because if this warning triggers, that's very much the first thing you want to know - why did reloc2sec_off() return failure for that symbol? So rather than just saying you can't handle some type of symbol without saying what the type _was_, just print out the type number too. Fixes: 24ff6525 ("objtool: Teach get_alt_entry() about more relocation types") Link: https://lore.kernel.org/lkml/CAHk-=wiZwq-0LknKhXN4M+T8jbxn_2i9mcKpO+OaBSSq_Eh7tg@mail.gmail.com/ Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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Linus Torvalds authored
The recent change to make objtool aware of more symbol relocation types (commit 24ff6525: "objtool: Teach get_alt_entry() about more relocation types") also added another check, and resulted in this objtool warning when building kvm on x86: arch/x86/kvm/emulate.o: warning: objtool: __ex_table+0x4: don't know how to handle reloc symbol type: kvm_fastop_exception The reason seems to be that kvm_fastop_exception() is marked as a global symbol, which causes the relocation to ke kept around for objtool. And at the same time, the kvm_fastop_exception definition (which is done as an inline asm statement) doesn't actually set the type of the global, which then makes objtool unhappy. The minimal fix is to just not mark kvm_fastop_exception as being a global symbol. It's only used in that one compilation unit anyway, so it was always pointless. That's how all the other local exception table labels are done. I'm not entirely happy about the kinds of games that the kvm code plays with doing its own exception handling, and the fact that it confused objtool is most definitely a symptom of the code being a bit too subtle and ad-hoc. But at least this trivial one-liner makes objtool no longer upset about what is going on. Fixes: 24ff6525 ("objtool: Teach get_alt_entry() about more relocation types") Link: https://lore.kernel.org/lkml/CAHk-=wiZwq-0LknKhXN4M+T8jbxn_2i9mcKpO+OaBSSq_Eh7tg@mail.gmail.com/ Cc: Borislav Petkov <bp@suse.de> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Sean Christopherson <seanjc@google.com> Cc: Vitaly Kuznetsov <vkuznets@redhat.com> Cc: Wanpeng Li <wanpengli@tencent.com> Cc: Jim Mattson <jmattson@google.com> Cc: Joerg Roedel <joro@8bytes.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Nathan Chancellor <nathan@kernel.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-miscLinus Torvalds authored
Pull char/misc driver fixes from Greg KH: "Here are some small misc driver fixes for 5.15-rc4. They are in two "groups": - ipack driver fixes for issues found by Johan Hovold - interconnect driver fixes for reported problems All of these have been in linux-next for a while with no reported issues" * tag 'char-misc-5.15-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: ipack: ipoctal: fix module reference leak ipack: ipoctal: fix missing allocation-failure check ipack: ipoctal: fix tty-registration error handling ipack: ipoctal: fix tty registration race ipack: ipoctal: fix stack information leak interconnect: qcom: sdm660: Add missing a2noc qos clocks dt-bindings: interconnect: sdm660: Add missing a2noc qos clocks interconnect: qcom: sdm660: Correct NOC_QOS_PRIORITY shift and mask interconnect: qcom: sdm660: Fix id of slv_cnoc_mnoc_cfg
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Linus Torvalds authored
Merge tag 'driver-core-5.15-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core Pull driver core fixes from Greg KH: "Here are some driver core and kernfs fixes for reported issues for 5.15-rc4. These fixes include: - kernfs positive dentry bugfix - debugfs_create_file_size error path fix - cpumask sysfs file bugfix to preserve the user/kernel abi (has been reported multiple times.) - devlink fixes for mdiobus devices as reported by the subsystem maintainers. Also included in here are some devlink debugging changes to make it easier for people to report problems when asked. They have already helped with the mdiobus and other subsystems reporting issues. All of these have been linux-next for a while with no reported issues" * tag 'driver-core-5.15-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: kernfs: also call kernfs_set_rev() for positive dentry driver core: Add debug logs when fwnode links are added/deleted driver core: Create __fwnode_link_del() helper function driver core: Set deferred probe reason when deferred by driver core net: mdiobus: Set FWNODE_FLAG_NEEDS_CHILD_BOUND_ON_ADD for mdiobus parents driver core: fw_devlink: Add support for FWNODE_FLAG_NEEDS_CHILD_BOUND_ON_ADD driver core: fw_devlink: Improve handling of cyclic dependencies cpumask: Omit terminating null byte in cpumap_print_{list,bitmask}_to_buf debugfs: debugfs_create_file_size(): use IS_ERR to check for error
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipLinus Torvalds authored
Pull scheduler fixes from Borislav Petkov: - Tell the compiler to always inline is_percpu_thread() - Make sure tunable_scaling buffer is null-terminated after an update in sysfs - Fix LTP named regression due to cgroup list ordering * tag 'sched_urgent_for_v5.15_rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: sched: Always inline is_percpu_thread() sched/fair: Null terminate buffer when updating tunable_scaling sched/fair: Add ancestors of unthrottled undecayed cfs_rq
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipLinus Torvalds authored
Pull perf fixes from Borislav Petkov: - Make sure the destroy callback is reset when a event initialization fails - Update the event constraints for Icelake - Make sure the active time of an event is updated even for inactive events * tag 'perf_urgent_for_v5.15_rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: perf/core: fix userpage->time_enabled of inactive events perf/x86/intel: Update event constraints for ICX perf/x86: Reset destroy callback on event init failure
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipLinus Torvalds authored
Pull objtool fix from Borislav Petkov: - Handle symbol relocations properly due to changes in the toolchains which remove section symbols now * tag 'objtool_urgent_for_v5.15_rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: objtool: Teach get_alt_entry() about more relocation types
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- Oct 03, 2021
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Linus Torvalds authored
Merge tag 'hwmon-for-v5.15-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging Pull hwmon fixes from Guenter Roeck: - Fixed various potential NULL pointer accesses in w8379* drivers - Improved error handling, fault reporting, and fixed rounding in thmp421 driver - Fixed error handling in ltc2947 driver - Added missing attribute to pmbus/mp2975 driver - Fixed attribute values in pbus/ibm-cffps, occ, and mlxreg-fan drivers - Removed unused residual code from k10temp driver * tag 'hwmon-for-v5.15-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging: hwmon: (w83793) Fix NULL pointer dereference by removing unnecessary structure field hwmon: (w83792d) Fix NULL pointer dereference by removing unnecessary structure field hwmon: (w83791d) Fix NULL pointer dereference by removing unnecessary structure field hwmon: (pmbus/mp2975) Add missed POUT attribute for page 1 mp2975 controller hwmon: (pmbus/ibm-cffps) max_power_out swap changes hwmon: (occ) Fix P10 VRM temp sensors hwmon: (ltc2947) Properly handle errors when looking for the external clock hwmon: (tmp421) fix rounding for negative values hwmon: (tmp421) report /PVLD condition as fault hwmon: (tmp421) handle I2C errors hwmon: (mlxreg-fan) Return non-zero value when fan current state is enforced from sysfs hwmon: (k10temp) Remove residues of current and voltage
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git://git.samba.org/ksmbdLinus Torvalds authored
Pull ksmbd server fixes from Steve French: "Eleven fixes for the ksmbd kernel server, mostly security related: - an important fix for disabling weak NTLMv1 authentication - seven security (improved buffer overflow checks) fixes - fix for wrong infolevel struct used in some getattr/setattr paths - two small documentation fixes" * tag '5.15-rc3-ksmbd-fixes' of git://git.samba.org/ksmbd: ksmbd: missing check for NULL in convert_to_nt_pathname() ksmbd: fix transform header validation ksmbd: add buffer validation for SMB2_CREATE_CONTEXT ksmbd: add validation in smb2 negotiate ksmbd: add request buffer validation in smb2_set_info ksmbd: use correct basic info level in set_file_basic_info() ksmbd: remove NTLMv1 authentication ksmbd: fix documentation for 2 functions MAINTAINERS: rename cifs_common to smbfs_common in cifs and ksmbd entry ksmbd: fix invalid request buffer access in compound ksmbd: remove RFC1002 check in smb2 request
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git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsiLinus Torvalds authored
Pull SCSI fixes from James Bottomley: "Five fairly minor fixes and spelling updates, all in drivers. Even though the ufs fix is in tracing, it's a potentially exploitable use beyond end of array bug" * tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi: scsi: csiostor: Add module softdep on cxgb4 scsi: qla2xxx: Fix excessive messages during device logout scsi: virtio_scsi: Fix spelling mistake "Unsupport" -> "Unsupported" scsi: ses: Fix unsigned comparison with less than zero scsi: ufs: Fix illegal offset in UPIU event trace
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git://git.kernel.dk/linux-blockLinus Torvalds authored
Pull block fixes from Jens Axboe: "A few block fixes for this release: - Revert a BFQ commit that causes breakage for people. Unfortunately it was auto-selected for stable as well, so now 5.14.7 suffers from it too. Hopefully stable will pick up this revert quickly too, so we can remove the issue on that end as well. - Add a quirk for Apple NVMe controllers, which due to their non-compliance broke due to the introduction of command sequences (Keith) - Use shifts in nbd, fixing a __divdi3 issue (Nick)" * tag 'block-5.15-2021-10-01' of git://git.kernel.dk/linux-block: nbd: use shifts rather than multiplies Revert "block, bfq: honor already-setup queue merges" nvme: add command id quirk for apple controllers
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