user/sven/linux.git/kernel/sched, branch v5.9.13

sched: Fix rq->nr_iowait ordering

2020-11-24T12:39:07Z

[ Upstream commit ec618b84f6e15281cc3660664d34cd0dd2f2579e ] schedule() ttwu() deactivate_task(); if (p->on_rq && ...) // false atomic_dec(&task_rq(p)->nr_iowait); if (prev->in_iowait) atomic_inc(&rq->nr_iowait); Allows nr_iowait to be decremented before it gets incremented, resulting in more dodgy IO-wait numbers than usual. Note that because we can now do ttwu_queue_wakelist() before p->on_cpu==0, we lose the natural ordering and have to further delay the decrement. Fixes: c6e7bd7afaeb ("sched/core: Optimize ttwu() spinning on p->on_cpu") Reported-by: Tejun Heo Signed-off-by: Peter Zijlstra (Intel) Acked-by: Mel Gorman Link: https://lkml.kernel.org/r/20201117093829.GD3121429@hirez.programming.kicks-ass.net Signed-off-by: Sasha Levin

sched/fair: Fix overutilized update in enqueue_task_fair()

2020-11-24T12:39:06Z

[ Upstream commit 8e1ac4299a6e8726de42310d9c1379f188140c71 ] enqueue_task_fair() attempts to skip the overutilized update for new tasks as their util_avg is not accurate yet. However, the flag we check to do so is overwritten earlier on in the function, which makes the condition pretty much a nop. Fix this by saving the flag early on. Fixes: 2802bf3cd936 ("sched/fair: Add over-utilization/tipping point indicator") Reported-by: Rick Yiu Signed-off-by: Quentin Perret Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Vincent Guittot Reviewed-by: Valentin Schneider Link: https://lkml.kernel.org/r/20201112111201.2081902-1-qperret@google.com Signed-off-by: Sasha Levin

cpufreq: Introduce governor flags

2020-11-18T18:22:30Z

commit 9a2a9ebc0a758d887ee06e067e9f7f0b36ff7574 upstream. A new cpufreq governor flag will be added subsequently, so replace the bool dynamic_switching fleid in struct cpufreq_governor with a flags field and introduce CPUFREQ_GOV_DYNAMIC_SWITCHING to set for the "dynamic switching" governors instead of it. No intentional functional impact. Signed-off-by: Rafael J. Wysocki Acked-by: Viresh Kumar Signed-off-by: Greg Kroah-Hartman

cpufreq: schedutil: Always call driver if CPUFREQ_NEED_UPDATE_LIMITS is set

2020-11-05T10:51:57Z

commit d1e7c2996e988866e7ceceb4641a0886885b7889 upstream. Because sugov_update_next_freq() may skip a frequency update even if the need_freq_update flag has been set for the policy at hand, policy limits updates may not take effect as expected. For example, if the intel_pstate driver operates in the passive mode with HWP enabled, it needs to update the HWP min and max limits when the policy min and max limits change, respectively, but that may not happen if the target frequency does not change along with the limit at hand. In particular, if the policy min is changed first, causing the target frequency to be adjusted to it, and the policy max limit is changed later to the same value, the HWP max limit will not be updated to follow it as expected, because the target frequency is still equal to the policy min limit and it will not change until that limit is updated. To address this issue, modify get_next_freq() to let the driver callback run if the CPUFREQ_NEED_UPDATE_LIMITS cpufreq driver flag is set regardless of whether or not the new frequency to set is equal to the previous one. Fixes: f6ebbcf08f37 ("cpufreq: intel_pstate: Implement passive mode with HWP enabled") Reported-by: Zhang Rui Tested-by: Zhang Rui Cc: 5.9+ # 5.9+: 1c534352f47f cpufreq: Introduce CPUFREQ_NEED_UPDATE_LIMITS ... Cc: 5.9+ # 5.9+: a62f68f5ca53 cpufreq: Introduce cpufreq_driver_test_flags() Signed-off-by: Rafael J. Wysocki Acked-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki Signed-off-by: Greg Kroah-Hartman

sched/features: Fix !CONFIG_JUMP_LABEL case

2020-10-29T09:12:07Z

[ Upstream commit a73f863af4ce9730795eab7097fb2102e6854365 ] Commit: 765cc3a4b224e ("sched/core: Optimize sched_feat() for !CONFIG_SCHED_DEBUG builds") made sched features static for !CONFIG_SCHED_DEBUG configurations, but overlooked the CONFIG_SCHED_DEBUG=y and !CONFIG_JUMP_LABEL cases. For the latter echoing changes to /sys/kernel/debug/sched_features has the nasty effect of effectively changing what sched_features reports, but without actually changing the scheduler behaviour (since different translation units get different sysctl_sched_features). Fix CONFIG_SCHED_DEBUG=y and !CONFIG_JUMP_LABEL configurations by properly restructuring ifdefs. Fixes: 765cc3a4b224e ("sched/core: Optimize sched_feat() for !CONFIG_SCHED_DEBUG builds") Co-developed-by: Daniel Bristot de Oliveira Signed-off-by: Daniel Bristot de Oliveira Signed-off-by: Juri Lelli Signed-off-by: Ingo Molnar Acked-by: Patrick Bellasi Reviewed-by: Valentin Schneider Link: https://lore.kernel.org/r/20201013053114.160628-1-juri.lelli@redhat.com Signed-off-by: Sasha Levin

sched/fair: Use dst group while checking imbalance for NUMA balancer

2020-10-29T09:11:01Z

[ Upstream commit 233e7aca4c8a2c764f556bba9644c36154017e7f ] Barry Song noted the following Something is wrong. In find_busiest_group(), we are checking if src has higher load, however, in task_numa_find_cpu(), we are checking if dst will have higher load after balancing. It seems it is not sensible to check src. It maybe cause wrong imbalance value, for example, if dst_running = env->dst_stats.nr_running + 1 results in 3 or above, and src_running = env->src_stats.nr_running - 1 results in 1; The current code is thinking imbalance as 0 since src_running is smaller than 2. This is inconsistent with load balancer. Basically, in find_busiest_group(), the NUMA imbalance is ignored if moving a task "from an almost idle domain" to a "domain with spare capacity". This patch forbids movement "from a misplaced domain" to "an almost idle domain" as that is closer to what the CPU load balancer expects. This patch is not a universal win. The old behaviour was intended to allow a task from an almost idle NUMA node to migrate to its preferred node if the destination had capacity but there are corner cases. For example, a NAS compute load could be parallelised to use 1/3rd of available CPUs but not all those potential tasks are active at all times allowing this logic to trigger. An obvious example is specjbb 2005 running various numbers of warehouses on a 2 socket box with 80 cpus. specjbb 5.9.0-rc4 5.9.0-rc4 vanilla dstbalance-v1r1 Hmean tput-1 46425.00 ( 0.00%) 43394.00 * -6.53%* Hmean tput-2 98416.00 ( 0.00%) 96031.00 * -2.42%* Hmean tput-3 150184.00 ( 0.00%) 148783.00 * -0.93%* Hmean tput-4 200683.00 ( 0.00%) 197906.00 * -1.38%* Hmean tput-5 236305.00 ( 0.00%) 245549.00 * 3.91%* Hmean tput-6 281559.00 ( 0.00%) 285692.00 * 1.47%* Hmean tput-7 338558.00 ( 0.00%) 334467.00 * -1.21%* Hmean tput-8 340745.00 ( 0.00%) 372501.00 * 9.32%* Hmean tput-9 424343.00 ( 0.00%) 413006.00 * -2.67%* Hmean tput-10 421854.00 ( 0.00%) 434261.00 * 2.94%* Hmean tput-11 493256.00 ( 0.00%) 485330.00 * -1.61%* Hmean tput-12 549573.00 ( 0.00%) 529959.00 * -3.57%* Hmean tput-13 593183.00 ( 0.00%) 555010.00 * -6.44%* Hmean tput-14 588252.00 ( 0.00%) 599166.00 * 1.86%* Hmean tput-15 623065.00 ( 0.00%) 642713.00 * 3.15%* Hmean tput-16 703924.00 ( 0.00%) 660758.00 * -6.13%* Hmean tput-17 666023.00 ( 0.00%) 697675.00 * 4.75%* Hmean tput-18 761502.00 ( 0.00%) 758360.00 * -0.41%* Hmean tput-19 796088.00 ( 0.00%) 798368.00 * 0.29%* Hmean tput-20 733564.00 ( 0.00%) 823086.00 * 12.20%* Hmean tput-21 840980.00 ( 0.00%) 856711.00 * 1.87%* Hmean tput-22 804285.00 ( 0.00%) 872238.00 * 8.45%* Hmean tput-23 795208.00 ( 0.00%) 889374.00 * 11.84%* Hmean tput-24 848619.00 ( 0.00%) 966783.00 * 13.92%* Hmean tput-25 750848.00 ( 0.00%) 903790.00 * 20.37%* Hmean tput-26 780523.00 ( 0.00%) 962254.00 * 23.28%* Hmean tput-27 1042245.00 ( 0.00%) 991544.00 * -4.86%* Hmean tput-28 1090580.00 ( 0.00%) 1035926.00 * -5.01%* Hmean tput-29 999483.00 ( 0.00%) 1082948.00 * 8.35%* Hmean tput-30 1098663.00 ( 0.00%) 1113427.00 * 1.34%* Hmean tput-31 1125671.00 ( 0.00%) 1134175.00 * 0.76%* Hmean tput-32 968167.00 ( 0.00%) 1250286.00 * 29.14%* Hmean tput-33 1077676.00 ( 0.00%) 1060893.00 * -1.56%* Hmean tput-34 1090538.00 ( 0.00%) 1090933.00 * 0.04%* Hmean tput-35 967058.00 ( 0.00%) 1107421.00 * 14.51%* Hmean tput-36 1051745.00 ( 0.00%) 1210663.00 * 15.11%* Hmean tput-37 1019465.00 ( 0.00%) 1351446.00 * 32.56%* Hmean tput-38 1083102.00 ( 0.00%) 1064541.00 * -1.71%* Hmean tput-39 1232990.00 ( 0.00%) 1303623.00 * 5.73%* Hmean tput-40 1175542.00 ( 0.00%) 1340943.00 * 14.07%* Hmean tput-41 1127826.00 ( 0.00%) 1339492.00 * 18.77%* Hmean tput-42 1198313.00 ( 0.00%) 1411023.00 * 17.75%* Hmean tput-43 1163733.00 ( 0.00%) 1228253.00 * 5.54%* Hmean tput-44 1305562.00 ( 0.00%) 1357886.00 * 4.01%* Hmean tput-45 1326752.00 ( 0.00%) 1406061.00 * 5.98%* Hmean tput-46 1339424.00 ( 0.00%) 1418451.00 * 5.90%* Hmean tput-47 1415057.00 ( 0.00%) 1381570.00 * -2.37%* Hmean tput-48 1392003.00 ( 0.00%) 1421167.00 * 2.10%* Hmean tput-49 1408374.00 ( 0.00%) 1418659.00 * 0.73%* Hmean tput-50 1359822.00 ( 0.00%) 1391070.00 * 2.30%* Hmean tput-51 1414246.00 ( 0.00%) 1392679.00 * -1.52%* Hmean tput-52 1432352.00 ( 0.00%) 1354020.00 * -5.47%* Hmean tput-53 1387563.00 ( 0.00%) 1409563.00 * 1.59%* Hmean tput-54 1406420.00 ( 0.00%) 1388711.00 * -1.26%* Hmean tput-55 1438804.00 ( 0.00%) 1387472.00 * -3.57%* Hmean tput-56 1399465.00 ( 0.00%) 1400296.00 * 0.06%* Hmean tput-57 1428132.00 ( 0.00%) 1396399.00 * -2.22%* Hmean tput-58 1432385.00 ( 0.00%) 1386253.00 * -3.22%* Hmean tput-59 1421612.00 ( 0.00%) 1371416.00 * -3.53%* Hmean tput-60 1429423.00 ( 0.00%) 1389412.00 * -2.80%* Hmean tput-61 1396230.00 ( 0.00%) 1351122.00 * -3.23%* Hmean tput-62 1418396.00 ( 0.00%) 1383098.00 * -2.49%* Hmean tput-63 1409918.00 ( 0.00%) 1374662.00 * -2.50%* Hmean tput-64 1410236.00 ( 0.00%) 1376216.00 * -2.41%* Hmean tput-65 1396405.00 ( 0.00%) 1364418.00 * -2.29%* Hmean tput-66 1395975.00 ( 0.00%) 1357326.00 * -2.77%* Hmean tput-67 1392986.00 ( 0.00%) 1349642.00 * -3.11%* Hmean tput-68 1386541.00 ( 0.00%) 1343261.00 * -3.12%* Hmean tput-69 1374407.00 ( 0.00%) 1342588.00 * -2.32%* Hmean tput-70 1377513.00 ( 0.00%) 1334654.00 * -3.11%* Hmean tput-71 1369319.00 ( 0.00%) 1334952.00 * -2.51%* Hmean tput-72 1354635.00 ( 0.00%) 1329005.00 * -1.89%* Hmean tput-73 1350933.00 ( 0.00%) 1318942.00 * -2.37%* Hmean tput-74 1351714.00 ( 0.00%) 1316347.00 * -2.62%* Hmean tput-75 1352198.00 ( 0.00%) 1309974.00 * -3.12%* Hmean tput-76 1349490.00 ( 0.00%) 1286064.00 * -4.70%* Hmean tput-77 1336131.00 ( 0.00%) 1303684.00 * -2.43%* Hmean tput-78 1308896.00 ( 0.00%) 1271024.00 * -2.89%* Hmean tput-79 1326703.00 ( 0.00%) 1290862.00 * -2.70%* Hmean tput-80 1336199.00 ( 0.00%) 1291629.00 * -3.34%* The performance at the mid-point is better but not universally better. The patch is a mixed bag depending on the workload, machine and overall levels of utilisation. Sometimes it's better (sometimes much better), other times it is worse (sometimes much worse). Given that there isn't a universally good decision in this section and more people seem to prefer the patch then it may be best to keep the LB decisions consistent and revisit imbalance handling when the load balancer code changes settle down. Jirka Hladky added the following observation. Our results are mostly in line with what you see. We observe big gains (20-50%) when the system is loaded to 1/3 of the maximum capacity and mixed results at the full load - some workloads benefit from the patch at the full load, others not, but performance changes at the full load are mostly within the noise of results (+/-5%). Overall, we think this patch is helpful. [mgorman@techsingularity.net: Rewrote changelog] Fixes: fb86f5b211 ("sched/numa: Use similar logic to the load balancer for moving between domains with spare capacity") Signed-off-by: Barry Song Signed-off-by: Mel Gorman Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/20200921221849.GI3179@techsingularity.net Signed-off-by: Sasha Levin

sched/fair: Fix wrong cpu selecting from isolated domain

2020-10-29T09:11:01Z

[ Upstream commit df3cb4ea1fb63ff326488efd671ba3c39034255e ] We've met problems that occasionally tasks with full cpumask (e.g. by putting it into a cpuset or setting to full affinity) were migrated to our isolated cpus in production environment. After some analysis, we found that it is due to the current select_idle_smt() not considering the sched_domain mask. Steps to reproduce on my 31-CPU hyperthreads machine: 1. with boot parameter: "isolcpus=domain,2-31" (thread lists: 0,16 and 1,17) 2. cgcreate -g cpu:test; cgexec -g cpu:test "test_threads" 3. some threads will be migrated to the isolated cpu16~17. Fix it by checking the valid domain mask in select_idle_smt(). Fixes: 10e2f1acd010 ("sched/core: Rewrite and improve select_idle_siblings()) Reported-by: Wetp Zhang Signed-off-by: Xunlei Pang Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Jiang Biao Reviewed-by: Vincent Guittot Link: https://lkml.kernel.org/r/1600930127-76857-1-git-send-email-xlpang@linux.alibaba.com Signed-off-by: Sasha Levin

sched/fair: Fix wrong negative conversion in find_energy_efficient_cpu()

2020-10-29T09:11:00Z

[ Upstream commit da0777d35f47892f359c3f73ea155870bb595700 ] In find_energy_efficient_cpu() 'cpu_cap' could be less that 'util'. It might be because of RT, DL (so higher sched class than CFS), irq or thermal pressure signal, which reduce the capacity value. In such situation the result of 'cpu_cap - util' might be negative but stored in the unsigned long. Then it might be compared with other unsigned long when uclamp_rq_util_with() reduced the 'util' such that is passes the fits_capacity() check. Prevent this situation and make the arithmetic more safe. Fixes: 1d42509e475cd ("sched/fair: Make EAS wakeup placement consider uclamp restrictions") Signed-off-by: Lukasz Luba Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Valentin Schneider Link: https://lkml.kernel.org/r/20200810083004.26420-1-lukasz.luba@arm.com Signed-off-by: Sasha Levin

Merge tag 'locking-urgent-2020-08-30' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2020-08-30T18:43:50Z

Pull locking fixes from Thomas Gleixner: "A set of fixes for lockdep, tracing and RCU: - Prevent recursion by using raw_cpu_* operations - Fixup the interrupt state in the cpu idle code to be consistent - Push rcu_idle_enter/exit() invocations deeper into the idle path so that the lock operations are inside the RCU watching sections - Move trace_cpu_idle() into generic code so it's called before RCU goes idle. - Handle raw_local_irq* vs. local_irq* operations correctly - Move the tracepoints out from under the lockdep recursion handling which turned out to be fragile and inconsistent" * tag 'locking-urgent-2020-08-30' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: lockdep,trace: Expose tracepoints lockdep: Only trace IRQ edges mips: Implement arch_irqs_disabled() arm64: Implement arch_irqs_disabled() nds32: Implement arch_irqs_disabled() locking/lockdep: Cleanup x86/entry: Remove unused THUNKs cpuidle: Move trace_cpu_idle() into generic code cpuidle: Make CPUIDLE_FLAG_TLB_FLUSHED generic sched,idle,rcu: Push rcu_idle deeper into the idle path cpuidle: Fixup IRQ state lockdep: Use raw_cpu_*() for per-cpu variables

cpuidle: Move trace_cpu_idle() into generic code

2020-08-26T10:41:54Z

Remove trace_cpu_idle() from the arch_cpu_idle() implementations and put it in the generic code, right before disabling RCU. Gets rid of more trace_*_rcuidle() users. Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Steven Rostedt (VMware) Reviewed-by: Thomas Gleixner Acked-by: Rafael J. Wysocki Tested-by: Marco Elver Link: https://lkml.kernel.org/r/20200821085348.428433395@infradead.org