kernel.git/kernel/sched/fair.c, branch linux-5.19.y

sched/numa: Initialise numa_migrate_retry

2022-08-17T13:14:20Z

[ Upstream commit 70ce3ea9aa4ed901c8a90de667df5ef307766e71 ] On clone, numa_migrate_retry is inherited from the parent which means that the first NUMA placement of a task is non-deterministic. This affects when load balancing recognises numa tasks and whether to migrate "regular", "remote" or "all" tasks between NUMA scheduler domains. Signed-off-by: Mel Gorman Signed-off-by: Peter Zijlstra (Intel) Tested-by: K Prateek Nayak Link: https://lore.kernel.org/r/20220520103519.1863-2-mgorman@techsingularity.net Signed-off-by: Sasha Levin

sched/fair: fix case with reduced capacity CPU

2022-08-17T13:14:01Z

[ Upstream commit c82a69629c53eda5233f13fc11c3c01585ef48a2 ] The capacity of the CPU available for CFS tasks can be reduced because of other activities running on the latter. In such case, it's worth trying to move CFS tasks on a CPU with more available capacity. The rework of the load balance has filtered the case when the CPU is classified to be fully busy but its capacity is reduced. Check if CPU's capacity is reduced while gathering load balance statistic and classify it group_misfit_task instead of group_fully_busy so we can try to move the load on another CPU. Reported-by: David Chen Reported-by: Zhang Qiao Signed-off-by: Vincent Guittot Signed-off-by: Peter Zijlstra (Intel) Tested-by: David Chen Tested-by: Zhang Qiao Link: https://lkml.kernel.org/r/20220708154401.21411-1-vincent.guittot@linaro.org Signed-off-by: Sasha Levin

sched/fair: Introduce SIS_UTIL to search idle CPU based on sum of util_avg

2022-08-17T13:14:01Z

[ Upstream commit 70fb5ccf2ebb09a0c8ebba775041567812d45f86 ] [Problem Statement] select_idle_cpu() might spend too much time searching for an idle CPU, when the system is overloaded. The following histogram is the time spent in select_idle_cpu(), when running 224 instances of netperf on a system with 112 CPUs per LLC domain: @usecs: [0] 533 | | [1] 5495 | | [2, 4) 12008 | | [4, 8) 239252 | | [8, 16) 4041924 |@@@@@@@@@@@@@@ | [16, 32) 12357398 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ | [32, 64) 14820255 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@| [64, 128) 13047682 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ | [128, 256) 8235013 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@ | [256, 512) 4507667 |@@@@@@@@@@@@@@@ | [512, 1K) 2600472 |@@@@@@@@@ | [1K, 2K) 927912 |@@@ | [2K, 4K) 218720 | | [4K, 8K) 98161 | | [8K, 16K) 37722 | | [16K, 32K) 6715 | | [32K, 64K) 477 | | [64K, 128K) 7 | | netperf latency usecs: ======= case load Lat_99th std% TCP_RR thread-224 257.39 ( 0.21) The time spent in select_idle_cpu() is visible to netperf and might have a negative impact. [Symptom analysis] The patch [1] from Mel Gorman has been applied to track the efficiency of select_idle_sibling. Copy the indicators here: SIS Search Efficiency(se_eff%): A ratio expressed as a percentage of runqueues scanned versus idle CPUs found. A 100% efficiency indicates that the target, prev or recent CPU of a task was idle at wakeup. The lower the efficiency, the more runqueues were scanned before an idle CPU was found. SIS Domain Search Efficiency(dom_eff%): Similar, except only for the slower SIS patch. SIS Fast Success Rate(fast_rate%): Percentage of SIS that used target, prev or recent CPUs. SIS Success rate(success_rate%): Percentage of scans that found an idle CPU. The test is based on Aubrey's schedtests tool, including netperf, hackbench, schbench and tbench. Test on vanilla kernel: schedstat_parse.py -f netperf_vanilla.log case load se_eff% dom_eff% fast_rate% success_rate% TCP_RR 28 threads 99.978 18.535 99.995 100.000 TCP_RR 56 threads 99.397 5.671 99.964 100.000 TCP_RR 84 threads 21.721 6.818 73.632 100.000 TCP_RR 112 threads 12.500 5.533 59.000 100.000 TCP_RR 140 threads 8.524 4.535 49.020 100.000 TCP_RR 168 threads 6.438 3.945 40.309 99.999 TCP_RR 196 threads 5.397 3.718 32.320 99.982 TCP_RR 224 threads 4.874 3.661 25.775 99.767 UDP_RR 28 threads 99.988 17.704 99.997 100.000 UDP_RR 56 threads 99.528 5.977 99.970 100.000 UDP_RR 84 threads 24.219 6.992 76.479 100.000 UDP_RR 112 threads 13.907 5.706 62.538 100.000 UDP_RR 140 threads 9.408 4.699 52.519 100.000 UDP_RR 168 threads 7.095 4.077 44.352 100.000 UDP_RR 196 threads 5.757 3.775 35.764 99.991 UDP_RR 224 threads 5.124 3.704 28.748 99.860 schedstat_parse.py -f schbench_vanilla.log (each group has 28 tasks) case load se_eff% dom_eff% fast_rate% success_rate% normal 1 mthread 99.152 6.400 99.941 100.000 normal 2 mthreads 97.844 4.003 99.908 100.000 normal 3 mthreads 96.395 2.118 99.917 99.998 normal 4 mthreads 55.288 1.451 98.615 99.804 normal 5 mthreads 7.004 1.870 45.597 61.036 normal 6 mthreads 3.354 1.346 20.777 34.230 normal 7 mthreads 2.183 1.028 11.257 21.055 normal 8 mthreads 1.653 0.825 7.849 15.549 schedstat_parse.py -f hackbench_vanilla.log (each group has 28 tasks) case load se_eff% dom_eff% fast_rate% success_rate% process-pipe 1 group 99.991 7.692 99.999 100.000 process-pipe 2 groups 99.934 4.615 99.997 100.000 process-pipe 3 groups 99.597 3.198 99.987 100.000 process-pipe 4 groups 98.378 2.464 99.958 100.000 process-pipe 5 groups 27.474 3.653 89.811 99.800 process-pipe 6 groups 20.201 4.098 82.763 99.570 process-pipe 7 groups 16.423 4.156 77.398 99.316 process-pipe 8 groups 13.165 3.920 72.232 98.828 process-sockets 1 group 99.977 5.882 99.999 100.000 process-sockets 2 groups 99.927 5.505 99.996 100.000 process-sockets 3 groups 99.397 3.250 99.980 100.000 process-sockets 4 groups 79.680 4.258 98.864 99.998 process-sockets 5 groups 7.673 2.503 63.659 92.115 process-sockets 6 groups 4.642 1.584 58.946 88.048 process-sockets 7 groups 3.493 1.379 49.816 81.164 process-sockets 8 groups 3.015 1.407 40.845 75.500 threads-pipe 1 group 99.997 0.000 100.000 100.000 threads-pipe 2 groups 99.894 2.932 99.997 100.000 threads-pipe 3 groups 99.611 4.117 99.983 100.000 threads-pipe 4 groups 97.703 2.624 99.937 100.000 threads-pipe 5 groups 22.919 3.623 87.150 99.764 threads-pipe 6 groups 18.016 4.038 80.491 99.557 threads-pipe 7 groups 14.663 3.991 75.239 99.247 threads-pipe 8 groups 12.242 3.808 70.651 98.644 threads-sockets 1 group 99.990 6.667 99.999 100.000 threads-sockets 2 groups 99.940 5.114 99.997 100.000 threads-sockets 3 groups 99.469 4.115 99.977 100.000 threads-sockets 4 groups 87.528 4.038 99.400 100.000 threads-sockets 5 groups 6.942 2.398 59.244 88.337 threads-sockets 6 groups 4.359 1.954 49.448 87.860 threads-sockets 7 groups 2.845 1.345 41.198 77.102 threads-sockets 8 groups 2.871 1.404 38.512 74.312 schedstat_parse.py -f tbench_vanilla.log case load se_eff% dom_eff% fast_rate% success_rate% loopback 28 threads 99.976 18.369 99.995 100.000 loopback 56 threads 99.222 7.799 99.934 100.000 loopback 84 threads 19.723 6.819 70.215 100.000 loopback 112 threads 11.283 5.371 55.371 99.999 loopback 140 threads 0.000 0.000 0.000 0.000 loopback 168 threads 0.000 0.000 0.000 0.000 loopback 196 threads 0.000 0.000 0.000 0.000 loopback 224 threads 0.000 0.000 0.000 0.000 According to the test above, if the system becomes busy, the SIS Search Efficiency(se_eff%) drops significantly. Although some benchmarks would finally find an idle CPU(success_rate% = 100%), it is doubtful whether it is worth it to search the whole LLC domain. [Proposal] It would be ideal to have a crystal ball to answer this question: How many CPUs must a wakeup path walk down, before it can find an idle CPU? Many potential metrics could be used to predict the number. One candidate is the sum of util_avg in this LLC domain. The benefit of choosing util_avg is that it is a metric of accumulated historic activity, which seems to be smoother than instantaneous metrics (such as rq->nr_running). Besides, choosing the sum of util_avg would help predict the load of the LLC domain more precisely, because SIS_PROP uses one CPU's idle time to estimate the total LLC domain idle time. In summary, the lower the util_avg is, the more select_idle_cpu() should scan for idle CPU, and vice versa. When the sum of util_avg in this LLC domain hits 85% or above, the scan stops. The reason to choose 85% as the threshold is that this is the imbalance_pct(117) when a LLC sched group is overloaded. Introduce the quadratic function: y = SCHED_CAPACITY_SCALE - p * x^2 and y'= y / SCHED_CAPACITY_SCALE x is the ratio of sum_util compared to the CPU capacity: x = sum_util / (llc_weight * SCHED_CAPACITY_SCALE) y' is the ratio of CPUs to be scanned in the LLC domain, and the number of CPUs to scan is calculated by: nr_scan = llc_weight * y' Choosing quadratic function is because: [1] Compared to the linear function, it scans more aggressively when the sum_util is low. [2] Compared to the exponential function, it is easier to calculate. [3] It seems that there is no accurate mapping between the sum of util_avg and the number of CPUs to be scanned. Use heuristic scan for now. For a platform with 112 CPUs per LLC, the number of CPUs to scan is: sum_util% 0 5 15 25 35 45 55 65 75 85 86 ... scan_nr 112 111 108 102 93 81 65 47 25 1 0 ... For a platform with 16 CPUs per LLC, the number of CPUs to scan is: sum_util% 0 5 15 25 35 45 55 65 75 85 86 ... scan_nr 16 15 15 14 13 11 9 6 3 0 0 ... Furthermore, to minimize the overhead of calculating the metrics in select_idle_cpu(), borrow the statistics from periodic load balance. As mentioned by Abel, on a platform with 112 CPUs per LLC, the sum_util calculated by periodic load balance after 112 ms would decay to about 0.5 * 0.5 * 0.5 * 0.7 = 8.75%, thus bringing a delay in reflecting the latest utilization. But it is a trade-off. Checking the util_avg in newidle load balance would be more frequent, but it brings overhead - multiple CPUs write/read the per-LLC shared variable and introduces cache contention. Tim also mentioned that, it is allowed to be non-optimal in terms of scheduling for the short-term variations, but if there is a long-term trend in the load behavior, the scheduler can adjust for that. When SIS_UTIL is enabled, the select_idle_cpu() uses the nr_scan calculated by SIS_UTIL instead of the one from SIS_PROP. As Peter and Mel suggested, SIS_UTIL should be enabled by default. This patch is based on the util_avg, which is very sensitive to the CPU frequency invariance. There is an issue that, when the max frequency has been clamp, the util_avg would decay insanely fast when the CPU is idle. Commit addca285120b ("cpufreq: intel_pstate: Handle no_turbo in frequency invariance") could be used to mitigate this symptom, by adjusting the arch_max_freq_ratio when turbo is disabled. But this issue is still not thoroughly fixed, because the current code is unaware of the user-specified max CPU frequency. [Test result] netperf and tbench were launched with 25% 50% 75% 100% 125% 150% 175% 200% of CPU number respectively. Hackbench and schbench were launched by 1, 2 ,4, 8 groups. Each test lasts for 100 seconds and repeats 3 times. The following is the benchmark result comparison between baseline:vanilla v5.19-rc1 and compare:patched kernel. Positive compare% indicates better performance. Each netperf test is a: netperf -4 -H 127.0.1 -t TCP/UDP_RR -c -C -l 100 netperf.throughput ======= case load baseline(std%) compare%( std%) TCP_RR 28 threads 1.00 ( 0.34) -0.16 ( 0.40) TCP_RR 56 threads 1.00 ( 0.19) -0.02 ( 0.20) TCP_RR 84 threads 1.00 ( 0.39) -0.47 ( 0.40) TCP_RR 112 threads 1.00 ( 0.21) -0.66 ( 0.22) TCP_RR 140 threads 1.00 ( 0.19) -0.69 ( 0.19) TCP_RR 168 threads 1.00 ( 0.18) -0.48 ( 0.18) TCP_RR 196 threads 1.00 ( 0.16) +194.70 ( 16.43) TCP_RR 224 threads 1.00 ( 0.16) +197.30 ( 7.85) UDP_RR 28 threads 1.00 ( 0.37) +0.35 ( 0.33) UDP_RR 56 threads 1.00 ( 11.18) -0.32 ( 0.21) UDP_RR 84 threads 1.00 ( 1.46) -0.98 ( 0.32) UDP_RR 112 threads 1.00 ( 28.85) -2.48 ( 19.61) UDP_RR 140 threads 1.00 ( 0.70) -0.71 ( 14.04) UDP_RR 168 threads 1.00 ( 14.33) -0.26 ( 11.16) UDP_RR 196 threads 1.00 ( 12.92) +186.92 ( 20.93) UDP_RR 224 threads 1.00 ( 11.74) +196.79 ( 18.62) Take the 224 threads as an example, the SIS search metrics changes are illustrated below: vanilla patched 4544492 +237.5% 15338634 sched_debug.cpu.sis_domain_search.avg 38539 +39686.8% 15333634 sched_debug.cpu.sis_failed.avg 128300000 -87.9% 15551326 sched_debug.cpu.sis_scanned.avg 5842896 +162.7% 15347978 sched_debug.cpu.sis_search.avg There is -87.9% less CPU scans after patched, which indicates lower overhead. Besides, with this patch applied, there is -13% less rq lock contention in perf-profile.calltrace.cycles-pp._raw_spin_lock.raw_spin_rq_lock_nested .try_to_wake_up.default_wake_function.woken_wake_function. This might help explain the performance improvement - Because this patch allows the waking task to remain on the previous CPU, rather than grabbing other CPUs' lock. Each hackbench test is a: hackbench -g $job --process/threads --pipe/sockets -l 1000000 -s 100 hackbench.throughput ========= case load baseline(std%) compare%( std%) process-pipe 1 group 1.00 ( 1.29) +0.57 ( 0.47) process-pipe 2 groups 1.00 ( 0.27) +0.77 ( 0.81) process-pipe 4 groups 1.00 ( 0.26) +1.17 ( 0.02) process-pipe 8 groups 1.00 ( 0.15) -4.79 ( 0.02) process-sockets 1 group 1.00 ( 0.63) -0.92 ( 0.13) process-sockets 2 groups 1.00 ( 0.03) -0.83 ( 0.14) process-sockets 4 groups 1.00 ( 0.40) +5.20 ( 0.26) process-sockets 8 groups 1.00 ( 0.04) +3.52 ( 0.03) threads-pipe 1 group 1.00 ( 1.28) +0.07 ( 0.14) threads-pipe 2 groups 1.00 ( 0.22) -0.49 ( 0.74) threads-pipe 4 groups 1.00 ( 0.05) +1.88 ( 0.13) threads-pipe 8 groups 1.00 ( 0.09) -4.90 ( 0.06) threads-sockets 1 group 1.00 ( 0.25) -0.70 ( 0.53) threads-sockets 2 groups 1.00 ( 0.10) -0.63 ( 0.26) threads-sockets 4 groups 1.00 ( 0.19) +11.92 ( 0.24) threads-sockets 8 groups 1.00 ( 0.08) +4.31 ( 0.11) Each tbench test is a: tbench -t 100 $job 127.0.0.1 tbench.throughput ====== case load baseline(std%) compare%( std%) loopback 28 threads 1.00 ( 0.06) -0.14 ( 0.09) loopback 56 threads 1.00 ( 0.03) -0.04 ( 0.17) loopback 84 threads 1.00 ( 0.05) +0.36 ( 0.13) loopback 112 threads 1.00 ( 0.03) +0.51 ( 0.03) loopback 140 threads 1.00 ( 0.02) -1.67 ( 0.19) loopback 168 threads 1.00 ( 0.38) +1.27 ( 0.27) loopback 196 threads 1.00 ( 0.11) +1.34 ( 0.17) loopback 224 threads 1.00 ( 0.11) +1.67 ( 0.22) Each schbench test is a: schbench -m $job -t 28 -r 100 -s 30000 -c 30000 schbench.latency_90%_us ======== case load baseline(std%) compare%( std%) normal 1 mthread 1.00 ( 31.22) -7.36 ( 20.25)* normal 2 mthreads 1.00 ( 2.45) -0.48 ( 1.79) normal 4 mthreads 1.00 ( 1.69) +0.45 ( 0.64) normal 8 mthreads 1.00 ( 5.47) +9.81 ( 14.28) *Consider the Standard Deviation, this -7.36% regression might not be valid. Also, a OLTP workload with a commercial RDBMS has been tested, and there is no significant change. There were concerns that unbalanced tasks among CPUs would cause problems. For example, suppose the LLC domain is composed of 8 CPUs, and 7 tasks are bound to CPU0~CPU6, while CPU7 is idle: CPU0 CPU1 CPU2 CPU3 CPU4 CPU5 CPU6 CPU7 util_avg 1024 1024 1024 1024 1024 1024 1024 0 Since the util_avg ratio is 87.5%( = 7/8 ), which is higher than 85%, select_idle_cpu() will not scan, thus CPU7 is undetected during scan. But according to Mel, it is unlikely the CPU7 will be idle all the time because CPU7 could pull some tasks via CPU_NEWLY_IDLE. lkp(kernel test robot) has reported a regression on stress-ng.sock on a very busy system. According to the sched_debug statistics, it might be caused by SIS_UTIL terminates the scan and chooses a previous CPU earlier, and this might introduce more context switch, especially involuntary preemption, which impacts a busy stress-ng. This regression has shown that, not all benchmarks in every scenario benefit from idle CPU scan limit, and it needs further investigation. Besides, there is slight regression in hackbench's 16 groups case when the LLC domain has 16 CPUs. Prateek mentioned that we should scan aggressively in an LLC domain with 16 CPUs. Because the cost to search for an idle one among 16 CPUs is negligible. The current patch aims to propose a generic solution and only considers the util_avg. Something like the below could be applied on top of the current patch to fulfill the requirement: if (llc_weight <= 16) nr_scan = nr_scan * 32 / llc_weight; For LLC domain with 16 CPUs, the nr_scan will be expanded to 2 times large. The smaller the CPU number this LLC domain has, the larger nr_scan will be expanded. This needs further investigation. There is also ongoing work[2] from Abel to filter out the busy CPUs during wakeup, to further speed up the idle CPU scan. And it could be a following-up optimization on top of this change. Suggested-by: Tim Chen Suggested-by: Peter Zijlstra Signed-off-by: Chen Yu Signed-off-by: Peter Zijlstra (Intel) Tested-by: Yicong Yang Tested-by: Mohini Narkhede Tested-by: K Prateek Nayak Link: https://lore.kernel.org/r/20220612163428.849378-1-yu.c.chen@intel.com Signed-off-by: Sasha Levin

Merge tag 'kthread-cleanups-for-v5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace

2022-06-03T23:03:05Z

Pull kthread updates from Eric Biederman: "This updates init and user mode helper tasks to be ordinary user mode tasks. Commit 40966e316f86 ("kthread: Ensure struct kthread is present for all kthreads") caused init and the user mode helper threads that call kernel_execve to have struct kthread allocated for them. This struct kthread going away during execve in turned made a use after free of struct kthread possible. Here, commit 343f4c49f243 ("kthread: Don't allocate kthread_struct for init and umh") is enough to fix the use after free and is simple enough to be backportable. The rest of the changes pass struct kernel_clone_args to clean things up and cause the code to make sense. In making init and the user mode helpers tasks purely user mode tasks I ran into two complications. The function task_tick_numa was detecting tasks without an mm by testing for the presence of PF_KTHREAD. The initramfs code in populate_initrd_image was using flush_delayed_fput to ensuere the closing of all it's file descriptors was complete, and flush_delayed_fput does not work in a userspace thread. I have looked and looked and more complications and in my code review I have not found any, and neither has anyone else with the code sitting in linux-next" * tag 'kthread-cleanups-for-v5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: sched: Update task_tick_numa to ignore tasks without an mm fork: Stop allowing kthreads to call execve fork: Explicitly set PF_KTHREAD init: Deal with the init process being a user mode process fork: Generalize PF_IO_WORKER handling fork: Explicity test for idle tasks in copy_thread fork: Pass struct kernel_clone_args into copy_thread kthread: Don't allocate kthread_struct for init and umh

Merge tag 'sysctl-5.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux

2022-05-26T23:57:20Z

Pull sysctl updates from Luis Chamberlain: "For two kernel releases now kernel/sysctl.c has been being cleaned up slowly, since the tables were grossly long, sprinkled with tons of #ifdefs and all this caused merge conflicts with one susbystem or another. This tree was put together to help try to avoid conflicts with these cleanups going on different trees at time. So nothing exciting on this pull request, just cleanups. Thanks a lot to the Uniontech and Huawei folks for doing some of this nasty work" * tag 'sysctl-5.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux: (28 commits) sched: Fix build warning without CONFIG_SYSCTL reboot: Fix build warning without CONFIG_SYSCTL kernel/kexec_core: move kexec_core sysctls into its own file sysctl: minor cleanup in new_dir() ftrace: fix building with SYSCTL=y but DYNAMIC_FTRACE=n fs/proc: Introduce list_for_each_table_entry for proc sysctl mm: fix unused variable kernel warning when SYSCTL=n latencytop: move sysctl to its own file ftrace: fix building with SYSCTL=n but DYNAMIC_FTRACE=y ftrace: Fix build warning ftrace: move sysctl_ftrace_enabled to ftrace.c kernel/do_mount_initrd: move real_root_dev sysctls to its own file kernel/delayacct: move delayacct sysctls to its own file kernel/acct: move acct sysctls to its own file kernel/panic: move panic sysctls to its own file kernel/lockdep: move lockdep sysctls to its own file mm: move page-writeback sysctls to their own file mm: move oom_kill sysctls to their own file kernel/reboot: move reboot sysctls to its own file sched: Move energy_aware sysctls to topology.c ...

sched: Update task_tick_numa to ignore tasks without an mm

2022-05-11T17:41:48Z

Qian Cai wrote: > Reverting the last 3 commits of the series fixed a boot crash. > > 1b2552cbdbe0 fork: Stop allowing kthreads to call execve > 753550eb0ce1 fork: Explicitly set PF_KTHREAD > 68d85f0a33b0 init: Deal with the init process being a user mode process > > BUG: KASAN: null-ptr-deref in task_nr_scan_windows.isra.0 > arch_atomic_long_read at ./include/linux/atomic/atomic-long.h:29 > (inlined by) atomic_long_read at ./include/linux/atomic/atomic-instrumented.h:1266 > (inlined by) get_mm_counter at ./include/linux/mm.h:1996 > (inlined by) get_mm_rss at ./include/linux/mm.h:2049 > (inlined by) task_nr_scan_windows at kernel/sched/fair.c:1123 > Read of size 8 at addr 00000000000003d0 by task swapper/0/1 With the change to init and the user mode helper processes to not have PF_KTHREAD set before they call kernel_execve the PF_KTHREAD test in task_tick_numa became insufficient to detect all tasks that have "->mm == NULL". Correct that by testing for "->mm == NULL" directly. Reported-by: Qian Cai Tested-by: Qian Cai Fixes: 1b2552cbdbe0 ("fork: Stop allowing kthreads to call execve") Link: https://lkml.kernel.org/r/87r150ug1l.fsf_-_@email.froward.int.ebiederm.org Signed-off-by: "Eric W. Biederman"

Merge tag 'v5.18-rc5' into sched/core to pull in fixes & to resolve a conflict

2022-05-06T08:21:46Z

- sched/core is on a pretty old -rc1 base - refresh it to include recent fixes. - this also allows up to resolve a (trivial) .mailmap conflict Conflicts: .mailmap Signed-off-by: Ingo Molnar

sched: Fix missing prototype warnings

2022-05-01T08:03:43Z

A W=1 build emits more than a dozen missing prototype warnings related to scheduler and scheduler specific includes. Reported-by: kernel test robot Signed-off-by: Thomas Gleixner Acked-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/r/20220413133024.249118058@linutronix.de

sched/fair: Remove cfs_rq_tg_path()

2022-04-29T09:06:29Z

cfs_rq_tg_path() is used by a tracepoint-to traceevent (tp-2-te) converter to format the path of a taskgroup or autogroup respectively. It doesn't have any in-kernel users after the removal of the sched_trace_cfs_rq_path() helper function. cfs_rq_tg_path() can be coded in a tp-2-te converter. Remove it from kernel/sched/fair.c. Signed-off-by: Dietmar Eggemann Signed-off-by: Qais Yousef Signed-off-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/r/20220428144338.479094-3-qais.yousef@arm.com

sched/fair: Remove sched_trace_*() helper functions

2022-04-29T09:06:29Z

We no longer need them as we can use DWARF debug info or BTF + pahole to re-generate the required structs to compile against them for a given kernel. This moves the burden of maintaining these helper functions to the module. https://github.com/qais-yousef/sched_tp Note that pahole v1.15 is required at least for using DWARF. And for BTF v1.23 which is not yet released will be required. There's alignment problem that will lead to crashes in earlier versions when used with BTF. We should have enough infrastructure to make these helper functions now obsolete, so remove them. [Rewrote commit message to reflect the new alternative] Signed-off-by: Dietmar Eggemann Signed-off-by: Qais Yousef Signed-off-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/r/20220428144338.479094-2-qais.yousef@arm.com