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2022-10-17sched: Introduce struct balance_callback to avoid CFI mismatchesKees Cook4-20/+26
Introduce distinct struct balance_callback instead of performing function pointer casting which will trip CFI. Avoids warnings as found by Clang's future -Wcast-function-type-strict option: In file included from kernel/sched/core.c:84: kernel/sched/sched.h:1755:15: warning: cast from 'void (*)(struct rq *)' to 'void (*)(struct callback_head *)' converts to incompatible function type [-Wcast-function-type-strict] head->func = (void (*)(struct callback_head *))func; ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ No binary differences result from this change. This patch is a cleanup based on Brad Spengler/PaX Team's modifications to sched code in their last public patch of grsecurity/PaX based on my understanding of the code. Changes or omissions from the original code are mine and don't reflect the original grsecurity/PaX code. Reported-by: Sami Tolvanen <samitolvanen@google.com> Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Nathan Chancellor <nathan@kernel.org> Link: https://github.com/ClangBuiltLinux/linux/issues/1724 Link: https://lkml.kernel.org/r/20221008000758.2957718-1-keescook@chromium.org
2022-10-17sched/core: Fix comparison in sched_group_cookie_match()Lin Shengwang1-9/+9
In commit 97886d9dcd86 ("sched: Migration changes for core scheduling"), sched_group_cookie_match() was added to help determine if a cookie matches the core state. However, while it iterates the SMT group, it fails to actually use the RQ for each of the CPUs iterated, use cpu_rq(cpu) instead of rq to fix things. Fixes: 97886d9dcd86 ("sched: Migration changes for core scheduling") Signed-off-by: Lin Shengwang <linshengwang1@huawei.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20221008022709.642-1-linshengwang1@huawei.com
2022-10-14Merge tag 'sched-psi-2022-10-14' of ↵Linus Torvalds3-74/+213
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull PSI updates from Ingo Molnar: - Various performance optimizations, resulting in a 4%-9% speedup in the mmtests/config-scheduler-perfpipe micro-benchmark. - New interface to turn PSI on/off on a per cgroup level. * tag 'sched-psi-2022-10-14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: sched/psi: Per-cgroup PSI accounting disable/re-enable interface sched/psi: Cache parent psi_group to speed up group iteration sched/psi: Consolidate cgroup_psi() sched/psi: Add PSI_IRQ to track IRQ/SOFTIRQ pressure sched/psi: Remove NR_ONCPU task accounting sched/psi: Optimize task switch inside shared cgroups again sched/psi: Move private helpers to sched/stats.h sched/psi: Save percpu memory when !psi_cgroups_enabled sched/psi: Don't create cgroup PSI files when psi_disabled sched/psi: Fix periodic aggregation shut off
2022-10-11Merge tag 'mm-stable-2022-10-08' of ↵Linus Torvalds4-3/+189
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Pull MM updates from Andrew Morton: - Yu Zhao's Multi-Gen LRU patches are here. They've been under test in linux-next for a couple of months without, to my knowledge, any negative reports (or any positive ones, come to that). - Also the Maple Tree from Liam Howlett. An overlapping range-based tree for vmas. It it apparently slightly more efficient in its own right, but is mainly targeted at enabling work to reduce mmap_lock contention. Liam has identified a number of other tree users in the kernel which could be beneficially onverted to mapletrees. Yu Zhao has identified a hard-to-hit but "easy to fix" lockdep splat at [1]. This has yet to be addressed due to Liam's unfortunately timed vacation. He is now back and we'll get this fixed up. - Dmitry Vyukov introduces KMSAN: the Kernel Memory Sanitizer. It uses clang-generated instrumentation to detect used-unintialized bugs down to the single bit level. KMSAN keeps finding bugs. New ones, as well as the legacy ones. - Yang Shi adds a userspace mechanism (madvise) to induce a collapse of memory into THPs. - Zach O'Keefe has expanded Yang Shi's madvise(MADV_COLLAPSE) to support file/shmem-backed pages. - userfaultfd updates from Axel Rasmussen - zsmalloc cleanups from Alexey Romanov - cleanups from Miaohe Lin: vmscan, hugetlb_cgroup, hugetlb and memory-failure - Huang Ying adds enhancements to NUMA balancing memory tiering mode's page promotion, with a new way of detecting hot pages. - memcg updates from Shakeel Butt: charging optimizations and reduced memory consumption. - memcg cleanups from Kairui Song. - memcg fixes and cleanups from Johannes Weiner. - Vishal Moola provides more folio conversions - Zhang Yi removed ll_rw_block() :( - migration enhancements from Peter Xu - migration error-path bugfixes from Huang Ying - Aneesh Kumar added ability for a device driver to alter the memory tiering promotion paths. For optimizations by PMEM drivers, DRM drivers, etc. - vma merging improvements from Jakub Matěn. - NUMA hinting cleanups from David Hildenbrand. - xu xin added aditional userspace visibility into KSM merging activity. - THP & KSM code consolidation from Qi Zheng. - more folio work from Matthew Wilcox. - KASAN updates from Andrey Konovalov. - DAMON cleanups from Kaixu Xia. - DAMON work from SeongJae Park: fixes, cleanups. - hugetlb sysfs cleanups from Muchun Song. - Mike Kravetz fixes locking issues in hugetlbfs and in hugetlb core. Link: https://lkml.kernel.org/r/CAOUHufZabH85CeUN-MEMgL8gJGzJEWUrkiM58JkTbBhh-jew0Q@mail.gmail.com [1] * tag 'mm-stable-2022-10-08' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (555 commits) hugetlb: allocate vma lock for all sharable vmas hugetlb: take hugetlb vma_lock when clearing vma_lock->vma pointer hugetlb: fix vma lock handling during split vma and range unmapping mglru: mm/vmscan.c: fix imprecise comments mm/mglru: don't sync disk for each aging cycle mm: memcontrol: drop dead CONFIG_MEMCG_SWAP config symbol mm: memcontrol: use do_memsw_account() in a few more places mm: memcontrol: deprecate swapaccounting=0 mode mm: memcontrol: don't allocate cgroup swap arrays when memcg is disabled mm/secretmem: remove reduntant return value mm/hugetlb: add available_huge_pages() func mm: remove unused inline functions from include/linux/mm_inline.h selftests/vm: add selftest for MADV_COLLAPSE of uffd-minor memory selftests/vm: add file/shmem MADV_COLLAPSE selftest for cleared pmd selftests/vm: add thp collapse shmem testing selftests/vm: add thp collapse file and tmpfs testing selftests/vm: modularize thp collapse memory operations selftests/vm: dedup THP helpers mm/khugepaged: add tracepoint to hpage_collapse_scan_file() mm/madvise: add file and shmem support to MADV_COLLAPSE ...
2022-10-10Merge tag 'bitmap-6.1-rc1' of https://github.com/norov/linuxLinus Torvalds1-4/+1
Pull bitmap updates from Yury Norov: - Fix unsigned comparison to -1 in CPUMAP_FILE_MAX_BYTES (Phil Auld) - cleanup nr_cpu_ids vs nr_cpumask_bits mess (me) This series cleans that mess and adds new config FORCE_NR_CPUS that allows to optimize cpumask subsystem if the number of CPUs is known at compile-time. - optimize find_bit() functions (me) Reworks find_bit() functions based on new FIND_{FIRST,NEXT}_BIT() macros. - add find_nth_bit() (me) Adds find_nth_bit(), which is ~70 times faster than bitcounting with for_each() loop: for_each_set_bit(bit, mask, size) if (n-- == 0) return bit; Also adds bitmap_weight_and() to let people replace this pattern: tmp = bitmap_alloc(nbits); bitmap_and(tmp, map1, map2, nbits); weight = bitmap_weight(tmp, nbits); bitmap_free(tmp); with a single bitmap_weight_and() call. - repair cpumask_check() (me) After switching cpumask to use nr_cpu_ids, cpumask_check() started generating many false-positive warnings. This series fixes it. - Add for_each_cpu_andnot() and for_each_cpu_andnot() (Valentin Schneider) Extends the API with one more function and applies it in sched/core. * tag 'bitmap-6.1-rc1' of https://github.com/norov/linux: (28 commits) sched/core: Merge cpumask_andnot()+for_each_cpu() into for_each_cpu_andnot() lib/test_cpumask: Add for_each_cpu_and(not) tests cpumask: Introduce for_each_cpu_andnot() lib/find_bit: Introduce find_next_andnot_bit() cpumask: fix checking valid cpu range lib/bitmap: add tests for for_each() loops lib/find: optimize for_each() macros lib/bitmap: introduce for_each_set_bit_wrap() macro lib/find_bit: add find_next{,_and}_bit_wrap cpumask: switch for_each_cpu{,_not} to use for_each_bit() net: fix cpu_max_bits_warn() usage in netif_attrmask_next{,_and} cpumask: add cpumask_nth_{,and,andnot} lib/bitmap: remove bitmap_ord_to_pos lib/bitmap: add tests for find_nth_bit() lib: add find_nth{,_and,_andnot}_bit() lib/bitmap: add bitmap_weight_and() lib/bitmap: don't call __bitmap_weight() in kernel code tools: sync find_bit() implementation lib/find_bit: optimize find_next_bit() functions lib/find_bit: create find_first_zero_bit_le() ...
2022-10-10Merge tag 'sched-core-2022-10-07' of ↵Linus Torvalds11-297/+265
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull scheduler updates from Ingo Molnar: "Debuggability: - Change most occurances of BUG_ON() to WARN_ON_ONCE() - Reorganize & fix TASK_ state comparisons, turn it into a bitmap - Update/fix misc scheduler debugging facilities Load-balancing & regular scheduling: - Improve the behavior of the scheduler in presence of lot of SCHED_IDLE tasks - in particular they should not impact other scheduling classes. - Optimize task load tracking, cleanups & fixes - Clean up & simplify misc load-balancing code Freezer: - Rewrite the core freezer to behave better wrt thawing and be simpler in general, by replacing PF_FROZEN with TASK_FROZEN & fixing/adjusting all the fallout. Deadline scheduler: - Fix the DL capacity-aware code - Factor out dl_task_is_earliest_deadline() & replenish_dl_new_period() - Relax/optimize locking in task_non_contending() Cleanups: - Factor out the update_current_exec_runtime() helper - Various cleanups, simplifications" * tag 'sched-core-2022-10-07' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (41 commits) sched: Fix more TASK_state comparisons sched: Fix TASK_state comparisons sched/fair: Move call to list_last_entry() in detach_tasks sched/fair: Cleanup loop_max and loop_break sched/fair: Make sure to try to detach at least one movable task sched: Show PF_flag holes freezer,sched: Rewrite core freezer logic sched: Widen TAKS_state literals sched/wait: Add wait_event_state() sched/completion: Add wait_for_completion_state() sched: Add TASK_ANY for wait_task_inactive() sched: Change wait_task_inactive()s match_state freezer,umh: Clean up freezer/initrd interaction freezer: Have {,un}lock_system_sleep() save/restore flags sched: Rename task_running() to task_on_cpu() sched/fair: Cleanup for SIS_PROP sched/fair: Default to false in test_idle_cores() sched/fair: Remove useless check in select_idle_core() sched/fair: Avoid double search on same cpu sched/fair: Remove redundant check in select_idle_smt() ...
2022-10-07Merge tag 'for-6.1/block-2022-10-03' of git://git.kernel.dk/linuxLinus Torvalds1-0/+2
Pull block updates from Jens Axboe: - NVMe pull requests via Christoph: - handle number of queue changes in the TCP and RDMA drivers (Daniel Wagner) - allow changing the number of queues in nvmet (Daniel Wagner) - also consider host_iface when checking ip options (Daniel Wagner) - don't map pages which can't come from HIGHMEM (Fabio M. De Francesco) - avoid unnecessary flush bios in nvmet (Guixin Liu) - shrink and better pack the nvme_iod structure (Keith Busch) - add comment for unaligned "fake" nqn (Linjun Bao) - print actual source IP address through sysfs "address" attr (Martin Belanger) - various cleanups (Jackie Liu, Wolfram Sang, Genjian Zhang) - handle effects after freeing the request (Keith Busch) - copy firmware_rev on each init (Keith Busch) - restrict management ioctls to admin (Keith Busch) - ensure subsystem reset is single threaded (Keith Busch) - report the actual number of tagset maps in nvme-pci (Keith Busch) - small fabrics authentication fixups (Christoph Hellwig) - add common code for tagset allocation and freeing (Christoph Hellwig) - stop using the request_queue in nvmet (Christoph Hellwig) - set min_align_mask before calculating max_hw_sectors (Rishabh Bhatnagar) - send a rediscover uevent when a persistent discovery controller reconnects (Sagi Grimberg) - misc nvmet-tcp fixes (Varun Prakash, zhenwei pi) - MD pull request via Song: - Various raid5 fix and clean up, by Logan Gunthorpe and David Sloan. - Raid10 performance optimization, by Yu Kuai. - sbitmap wakeup hang fixes (Hugh, Keith, Jan, Yu) - IO scheduler switching quisce fix (Keith) - s390/dasd block driver updates (Stefan) - support for recovery for the ublk driver (ZiyangZhang) - rnbd drivers fixes and updates (Guoqing, Santosh, ye, Christoph) - blk-mq and null_blk map fixes (Bart) - various bcache fixes (Coly, Jilin, Jules) - nbd signal hang fix (Shigeru) - block writeback throttling fix (Yu) - optimize the passthrough mapping handling (me) - prepare block cgroups to being gendisk based (Christoph) - get rid of an old PSI hack in the block layer, moving it to the callers instead where it belongs (Christoph) - blk-throttle fixes and cleanups (Yu) - misc fixes and cleanups (Liu Shixin, Liu Song, Miaohe, Pankaj, Ping-Xiang, Wolfram, Saurabh, Li Jinlin, Li Lei, Lin, Li zeming, Miaohe, Bart, Coly, Gaosheng * tag 'for-6.1/block-2022-10-03' of git://git.kernel.dk/linux: (162 commits) sbitmap: fix lockup while swapping block: add rationale for not using blk_mq_plug() when applicable block: adapt blk_mq_plug() to not plug for writes that require a zone lock s390/dasd: use blk_mq_alloc_disk blk-cgroup: don't update the blkg lookup hint in blkg_conf_prep nvmet: don't look at the request_queue in nvmet_bdev_set_limits nvmet: don't look at the request_queue in nvmet_bdev_zone_mgmt_emulate_all blk-mq: use quiesced elevator switch when reinitializing queues block: replace blk_queue_nowait with bdev_nowait nvme: remove nvme_ctrl_init_connect_q nvme-loop: use the tagset alloc/free helpers nvme-loop: store the generic nvme_ctrl in set->driver_data nvme-loop: initialize sqsize later nvme-fc: use the tagset alloc/free helpers nvme-fc: store the generic nvme_ctrl in set->driver_data nvme-fc: keep ctrl->sqsize in sync with opts->queue_size nvme-rdma: use the tagset alloc/free helpers nvme-rdma: store the generic nvme_ctrl in set->driver_data nvme-tcp: use the tagset alloc/free helpers nvme-tcp: store the generic nvme_ctrl in set->driver_data ...
2022-10-06sched/core: Merge cpumask_andnot()+for_each_cpu() into for_each_cpu_andnot()Valentin Schneider1-4/+1
This removes the second use of the sched_core_mask temporary mask. Suggested-by: Yury Norov <yury.norov@gmail.com> Signed-off-by: Valentin Schneider <vschneid@redhat.com>
2022-10-03Merge tag 'pm-6.1-rc1' of ↵Linus Torvalds1-15/+15
git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm Pull power management updates from Rafael Wysocki: "These add support for some new hardware, extend the existing hardware support, fix some issues and clean up code Specifics: - Add isupport for Tiger Lake in no-HWP mode to intel_pstate (Doug Smythies) - Update the AMD P-state driver (Perry Yuan): - Fix wrong lowest perf fetch - Map desired perf into pstate scope for powersave governor - Update pstate frequency transition delay time - Fix initial highest_perf value - Clean up - Move max CPU capacity to sugov_policy in the schedutil cpufreq governor (Lukasz Luba) - Add SM6115 to cpufreq-dt blocklist (Adam Skladowski) - Add support for Tegra239 and minor cleanups (Sumit Gupta, ye xingchen, and Yang Yingliang) - Add freq qos for qcom cpufreq driver and minor cleanups (Xuewen Yan, and Viresh Kumar) - Minor cleanups around functions called at module_init() (Xiu Jianfeng) - Use module_init and add module_exit for bmips driver (Zhang Jianhua) - Add AlderLake-N support to intel_idle (Zhang Rui) - Replace strlcpy() with unused retval with strscpy() in intel_idle (Wolfram Sang) - Remove redundant check from cpuidle_switch_governor() (Yu Liao) - Replace strlcpy() with unused retval with strscpy() in the powernv cpuidle driver (Wolfram Sang) - Drop duplicate word from a comment in the coupled cpuidle driver (Jason Wang) - Make rpm_resume() return -EINPROGRESS if RPM_NOWAIT is passed to it in the flags and the device is about to resume (Rafael Wysocki) - Add extra debugging statement for multiple active IRQs to system wakeup handling code (Mario Limonciello) - Replace strlcpy() with unused retval with strscpy() in the core system suspend support code (Wolfram Sang) - Update the intel_rapl power capping driver: - Use standard Energy Unit for SPR Dram RAPL domain (Zhang Rui). - Add support for RAPTORLAKE_S (Zhang Rui). - Fix UBSAN shift-out-of-bounds issue (Chao Qin) - Handle -EPROBE_DEFER when regulator is not probed on mtk-ci-devfreq.c (AngeloGioacchino Del Regno) - Fix message typo and use dev_err_probe() in rockchip-dfi.c (Christophe JAILLET)" * tag 'pm-6.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (29 commits) cpufreq: qcom-cpufreq-hw: Add cpufreq qos for LMh cpufreq: Add __init annotation to module init funcs cpufreq: tegra194: change tegra239_cpufreq_soc to static PM / devfreq: rockchip-dfi: Fix an error message PM / devfreq: mtk-cci: Handle sram regulator probe deferral powercap: intel_rapl: Use standard Energy Unit for SPR Dram RAPL domain PM: runtime: Return -EINPROGRESS from rpm_resume() in the RPM_NOWAIT case intel_idle: Add AlderLake-N support powercap: intel_rapl: fix UBSAN shift-out-of-bounds issue cpufreq: tegra194: Add support for Tegra239 cpufreq: qcom-cpufreq-hw: Fix uninitialized throttled_freq warning cpufreq: intel_pstate: Add Tigerlake support in no-HWP mode powercap: intel_rapl: Add support for RAPTORLAKE_S cpufreq: amd-pstate: Fix initial highest_perf value cpuidle: Remove redundant check in cpuidle_switch_governor() PM: wakeup: Add extra debugging statement for multiple active IRQs cpufreq: tegra194: Remove the unneeded result variable PM: suspend: move from strlcpy() with unused retval to strscpy() intel_idle: move from strlcpy() with unused retval to strscpy() cpuidle: powernv: move from strlcpy() with unused retval to strscpy() ...
2022-10-03Merge branch 'pm-cpufreq'Rafael J. Wysocki1-15/+15
Merge cpufreq changes for 6.1-rc1: - Add isupport for Tiger Lake in no-HWP mode to intel_pstate (Doug Smythies). - Update the AMD P-state driver (Perry Yuan): * Fix wrong lowest perf fetch. * Map desired perf into pstate scope for powersave governor. * Update pstate frequency transition delay time. * Fix initial highest_perf value. * Clean up. - Move max CPU capacity to sugov_policy in the schedutil cpufreq governor (Lukasz Luba). - Add SM6115 to cpufreq-dt blocklist (Adam Skladowski). - Add support for Tegra239 and minor cleanups (Sumit Gupta, ye xingchen, and Yang Yingliang). - Add freq qos for qcom cpufreq driver and minor cleanups (Xuewen Yan, and Viresh Kumar). - Minor cleanups around functions called at module_init() (Xiu Jianfeng). - Use module_init and add module_exit for bmips driver (Zhang Jianhua). * pm-cpufreq: cpufreq: qcom-cpufreq-hw: Add cpufreq qos for LMh cpufreq: Add __init annotation to module init funcs cpufreq: tegra194: change tegra239_cpufreq_soc to static cpufreq: tegra194: Add support for Tegra239 cpufreq: qcom-cpufreq-hw: Fix uninitialized throttled_freq warning cpufreq: intel_pstate: Add Tigerlake support in no-HWP mode cpufreq: amd-pstate: Fix initial highest_perf value cpufreq: tegra194: Remove the unneeded result variable cpufreq: amd-pstate: update pstate frequency transition delay time cpufreq: amd_pstate: map desired perf into pstate scope for powersave governor cpufreq: amd_pstate: fix wrong lowest perf fetch cpufreq: amd-pstate: fix white-space cpufreq: amd-pstate: simplify cpudata pointer assignment cpufreq: bmips-cpufreq: Use module_init and add module_exit cpufreq: schedutil: Move max CPU capacity to sugov_policy cpufreq: Add SM6115 to cpufreq-dt-platdev blocklist
2022-10-03Merge tag 'rcu.2022.09.30a' of ↵Linus Torvalds1-0/+14
git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu Pull RCU updates from Paul McKenney: - Documentation updates. This is the first in a series from an ongoing review of the RCU documentation. "Why are people thinking -that- about RCU? Oh. Because that is an entirely reasonable interpretation of its documentation." - Miscellaneous fixes. - Improved memory allocation and heuristics. - Improve rcu_nocbs diagnostic output. - Add full-sized polled RCU grace period state values. These are the same size as an rcu_head structure, which is double that of the traditional unsigned long state values that may still be obtained from et_state_synchronize_rcu(). The added size avoids missing overlapping grace periods. This benefit is that call_rcu() can be replaced by polling, which can be attractive in situations where RCU-protected data is aged out of memory. Early in the series, the size of this state value is three unsigned longs. Later in the series, the fastpaths in synchronize_rcu() and synchronize_rcu_expedited() are reworked to permit the full state to be represented by only two unsigned longs. This reworking slows these two functions down in SMP kernels running either on single-CPU systems or on systems with all but one CPU offlined, but this should not be a significant problem. And if it somehow becomes a problem in some yet-as-unforeseen situations, three-value state values can be provided for only those situations. Finally, a pair of functions named same_state_synchronize_rcu() and same_state_synchronize_rcu_full() allow grace-period state values to be compared for equality. This permits users to maintain lists of data structures having the same state value, removing the need for per-data-structure grace-period state values, thus decreasing memory footprint. - Polled SRCU grace-period updates, including adding tests to rcutorture and reducing the incidence of Tiny SRCU grace-period-state counter wrap. - Improve Tasks RCU diagnostics and quiescent-state detection. * tag 'rcu.2022.09.30a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu: (55 commits) rcutorture: Use the barrier operation specified by cur_ops rcu-tasks: Make RCU Tasks Trace check for userspace execution rcu-tasks: Ensure RCU Tasks Trace loops have quiescent states rcu-tasks: Convert RCU_LOCKDEP_WARN() to WARN_ONCE() srcu: Make Tiny SRCU use full-sized grace-period counters srcu: Make Tiny SRCU poll_state_synchronize_srcu() more precise srcu: Add GP and maximum requested GP to Tiny SRCU rcutorture output rcutorture: Make "srcud" option also test polled grace-period API rcutorture: Limit read-side polling-API testing rcu: Add functions to compare grace-period state values rcutorture: Expand rcu_torture_write_types() first "if" statement rcutorture: Use 1-suffixed variable in rcu_torture_write_types() check rcu: Make synchronize_rcu() fastpath update only boot-CPU counters rcutorture: Adjust rcu_poll_need_2gp() for rcu_gp_oldstate field removal rcu: Remove ->rgos_polled field from rcu_gp_oldstate structure rcu: Make synchronize_rcu_expedited() fast path update .expedited_sequence rcu: Remove expedited grace-period fast-path forward-progress helper rcu: Make synchronize_rcu() fast path update ->gp_seq counters rcu-tasks: Remove grace-period fast-path rcu-tasks helper rcu: Set rcu_data structures' initial ->gpwrap value to true ...
2022-09-28sched: Fix TASK_state comparisonsPeter Zijlstra1-1/+1
Task state is fundamentally a bitmask; direct comparisons are probably not working as intended. Specifically the normal wait-state have a number of possible modifiers: TASK_UNINTERRUPTIBLE: TASK_WAKEKILL, TASK_NOLOAD, TASK_FREEZABLE TASK_INTERRUPTIBLE: TASK_FREEZABLE Specifically, the addition of TASK_FREEZABLE wrecked __wait_is_interruptible(). This however led to an audit of direct comparisons yielding the rest of the changes. Fixes: f5d39b020809 ("freezer,sched: Rewrite core freezer logic") Reported-by: Christian Borntraeger <borntraeger@linux.ibm.com> Debugged-by: Christian Borntraeger <borntraeger@linux.ibm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Tested-by: Christian Borntraeger <borntraeger@linux.ibm.com>
2022-09-27sched: use maple tree iterator to walk VMAsMatthew Wilcox (Oracle)1-3/+7
The linked list is slower than walking the VMAs using the maple tree. We can't use the VMA iterator here because it doesn't support moving to an earlier position. Link: https://lkml.kernel.org/r/20220906194824.2110408-49-Liam.Howlett@oracle.com Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Tested-by: Yu Zhao <yuzhao@google.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: David Hildenbrand <david@redhat.com> Cc: David Howells <dhowells@redhat.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: SeongJae Park <sj@kernel.org> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-09-27mm/demotion: update node_is_toptier to work with memory tiersAneesh Kumar K.V1-0/+1
With memory tier support we can have memory only NUMA nodes in the top tier from which we want to avoid promotion tracking NUMA faults. Update node_is_toptier to work with memory tiers. All NUMA nodes are by default top tier nodes. With lower(slower) memory tiers added we consider all memory tiers above a memory tier having CPU NUMA nodes as a top memory tier [sj@kernel.org: include missed header file, memory-tiers.h] Link: https://lkml.kernel.org/r/20220820190720.248704-1-sj@kernel.org [akpm@linux-foundation.org: mm/memory.c needs linux/memory-tiers.h] [aneesh.kumar@linux.ibm.com: make toptier_distance inclusive upper bound of toptiers] Link: https://lkml.kernel.org/r/20220830081457.118960-1-aneesh.kumar@linux.ibm.com Link: https://lkml.kernel.org/r/20220818131042.113280-10-aneesh.kumar@linux.ibm.com Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Reviewed-by: "Huang, Ying" <ying.huang@intel.com> Acked-by: Wei Xu <weixugc@google.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Bharata B Rao <bharata@amd.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Hesham Almatary <hesham.almatary@huawei.com> Cc: Jagdish Gediya <jvgediya.oss@gmail.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Tim Chen <tim.c.chen@intel.com> Cc: Yang Shi <shy828301@gmail.com> Cc: SeongJae Park <sj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-09-27mm: multi-gen LRU: support page table walksYu Zhao1-0/+1
To further exploit spatial locality, the aging prefers to walk page tables to search for young PTEs and promote hot pages. A kill switch will be added in the next patch to disable this behavior. When disabled, the aging relies on the rmap only. NB: this behavior has nothing similar with the page table scanning in the 2.4 kernel [1], which searches page tables for old PTEs, adds cold pages to swapcache and unmaps them. To avoid confusion, the term "iteration" specifically means the traversal of an entire mm_struct list; the term "walk" will be applied to page tables and the rmap, as usual. An mm_struct list is maintained for each memcg, and an mm_struct follows its owner task to the new memcg when this task is migrated. Given an lruvec, the aging iterates lruvec_memcg()->mm_list and calls walk_page_range() with each mm_struct on this list to promote hot pages before it increments max_seq. When multiple page table walkers iterate the same list, each of them gets a unique mm_struct; therefore they can run concurrently. Page table walkers ignore any misplaced pages, e.g., if an mm_struct was migrated, pages it left in the previous memcg will not be promoted when its current memcg is under reclaim. Similarly, page table walkers will not promote pages from nodes other than the one under reclaim. This patch uses the following optimizations when walking page tables: 1. It tracks the usage of mm_struct's between context switches so that page table walkers can skip processes that have been sleeping since the last iteration. 2. It uses generational Bloom filters to record populated branches so that page table walkers can reduce their search space based on the query results, e.g., to skip page tables containing mostly holes or misplaced pages. 3. It takes advantage of the accessed bit in non-leaf PMD entries when CONFIG_ARCH_HAS_NONLEAF_PMD_YOUNG=y. 4. It does not zigzag between a PGD table and the same PMD table spanning multiple VMAs. IOW, it finishes all the VMAs within the range of the same PMD table before it returns to a PGD table. This improves the cache performance for workloads that have large numbers of tiny VMAs [2], especially when CONFIG_PGTABLE_LEVELS=5. Server benchmark results: Single workload: fio (buffered I/O): no change Single workload: memcached (anon): +[8, 10]% Ops/sec KB/sec patch1-7: 1147696.57 44640.29 patch1-8: 1245274.91 48435.66 Configurations: no change Client benchmark results: kswapd profiles: patch1-7 48.16% lzo1x_1_do_compress (real work) 8.20% page_vma_mapped_walk (overhead) 7.06% _raw_spin_unlock_irq 2.92% ptep_clear_flush 2.53% __zram_bvec_write 2.11% do_raw_spin_lock 2.02% memmove 1.93% lru_gen_look_around 1.56% free_unref_page_list 1.40% memset patch1-8 49.44% lzo1x_1_do_compress (real work) 6.19% page_vma_mapped_walk (overhead) 5.97% _raw_spin_unlock_irq 3.13% get_pfn_folio 2.85% ptep_clear_flush 2.42% __zram_bvec_write 2.08% do_raw_spin_lock 1.92% memmove 1.44% alloc_zspage 1.36% memset Configurations: no change Thanks to the following developers for their efforts [3]. kernel test robot <lkp@intel.com> [1] https://lwn.net/Articles/23732/ [2] https://llvm.org/docs/ScudoHardenedAllocator.html [3] https://lore.kernel.org/r/202204160827.ekEARWQo-lkp@intel.com/ Link: https://lkml.kernel.org/r/20220918080010.2920238-9-yuzhao@google.com Signed-off-by: Yu Zhao <yuzhao@google.com> Acked-by: Brian Geffon <bgeffon@google.com> Acked-by: Jan Alexander Steffens (heftig) <heftig@archlinux.org> Acked-by: Oleksandr Natalenko <oleksandr@natalenko.name> Acked-by: Steven Barrett <steven@liquorix.net> Acked-by: Suleiman Souhlal <suleiman@google.com> Tested-by: Daniel Byrne <djbyrne@mtu.edu> Tested-by: Donald Carr <d@chaos-reins.com> Tested-by: Holger Hoffstätte <holger@applied-asynchrony.com> Tested-by: Konstantin Kharlamov <Hi-Angel@yandex.ru> Tested-by: Shuang Zhai <szhai2@cs.rochester.edu> Tested-by: Sofia Trinh <sofia.trinh@edi.works> Tested-by: Vaibhav Jain <vaibhav@linux.ibm.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Barry Song <baohua@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Hillf Danton <hdanton@sina.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Michael Larabel <Michael@MichaelLarabel.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Mike Rapoport <rppt@kernel.org> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Qi Zheng <zhengqi.arch@bytedance.com> Cc: Tejun Heo <tj@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-09-20sched/psi: export psi_memstall_{enter,leave}Christoph Hellwig1-0/+2
To properly account for all refaults from file system logic, file systems need to call psi_memstall_enter directly, so export it. Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Link: https://lore.kernel.org/r/20220915094200.139713-3-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-09-15sched/fair: Move call to list_last_entry() in detach_tasksVincent Guittot1-2/+2
Move the call to list_last_entry() in detach_tasks() after testing loop_max and loop_break. Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20220825122726.20819-4-vincent.guittot@linaro.org
2022-09-15sched/fair: Cleanup loop_max and loop_breakVincent Guittot3-12/+11
sched_nr_migrate_break is set to a fix value and never changes so we can replace it by a define SCHED_NR_MIGRATE_BREAK. Also, we adjust SCHED_NR_MIGRATE_BREAK to be aligned with the init value of sysctl_sched_nr_migrate which can be init to different values. Then, use SCHED_NR_MIGRATE_BREAK to init sysctl_sched_nr_migrate. The behavior stays unchanged unless you modify sysctl_sched_nr_migrate trough debugfs. Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20220825122726.20819-3-vincent.guittot@linaro.org
2022-09-15sched/fair: Make sure to try to detach at least one movable taskVincent Guittot1-3/+9
During load balance, we try at most env->loop_max time to move a task. But it can happen that the loop_max LRU tasks (ie tail of the cfs_tasks list) can't be moved to dst_cpu because of affinity. In this case, loop in the list until we found at least one. The maximum of detached tasks remained the same as before. Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20220825122726.20819-2-vincent.guittot@linaro.org
2022-09-12memory tiering: adjust hot threshold automaticallyHuang Ying2-5/+55
The promotion hot threshold is workload and system configuration dependent. So in this patch, a method to adjust the hot threshold automatically is implemented. The basic idea is to control the number of the candidate promotion pages to match the promotion rate limit. If the hint page fault latency of a page is less than the hot threshold, we will try to promote the page, and the page is called the candidate promotion page. If the number of the candidate promotion pages in the statistics interval is much more than the promotion rate limit, the hot threshold will be decreased to reduce the number of the candidate promotion pages. Otherwise, the hot threshold will be increased to increase the number of the candidate promotion pages. To make the above method works, in each statistics interval, the total number of the pages to check (on which the hint page faults occur) and the hot/cold distribution need to be stable. Because the page tables are scanned linearly in NUMA balancing, but the hot/cold distribution isn't uniform along the address usually, the statistics interval should be larger than the NUMA balancing scan period. So in the patch, the max scan period is used as statistics interval and it works well in our tests. Link: https://lkml.kernel.org/r/20220713083954.34196-4-ying.huang@intel.com Signed-off-by: "Huang, Ying" <ying.huang@intel.com> Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com> Tested-by: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Michal Hocko <mhocko@suse.com> Cc: osalvador <osalvador@suse.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@surriel.com> Cc: Shakeel Butt <shakeelb@google.com> Cc: Wei Xu <weixugc@google.com> Cc: Yang Shi <shy828301@gmail.com> Cc: Zhong Jiang <zhongjiang-ali@linux.alibaba.com> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-09-12memory tiering: rate limit NUMA migration throughputHuang Ying1-2/+31
In NUMA balancing memory tiering mode, if there are hot pages in slow memory node and cold pages in fast memory node, we need to promote/demote hot/cold pages between the fast and cold memory nodes. A choice is to promote/demote as fast as possible. But the CPU cycles and memory bandwidth consumed by the high promoting/demoting throughput will hurt the latency of some workload because of accessing inflating and slow memory bandwidth contention. A way to resolve this issue is to restrict the max promoting/demoting throughput. It will take longer to finish the promoting/demoting. But the workload latency will be better. This is implemented in this patch as the page promotion rate limit mechanism. The number of the candidate pages to be promoted to the fast memory node via NUMA balancing is counted, if the count exceeds the limit specified by the users, the NUMA balancing promotion will be stopped until the next second. A new sysctl knob kernel.numa_balancing_promote_rate_limit_MBps is added for the users to specify the limit. Link: https://lkml.kernel.org/r/20220713083954.34196-3-ying.huang@intel.com Signed-off-by: "Huang, Ying" <ying.huang@intel.com> Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com> Tested-by: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Michal Hocko <mhocko@suse.com> Cc: osalvador <osalvador@suse.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@surriel.com> Cc: Shakeel Butt <shakeelb@google.com> Cc: Wei Xu <weixugc@google.com> Cc: Yang Shi <shy828301@gmail.com> Cc: Zhong Jiang <zhongjiang-ali@linux.alibaba.com> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-09-12memory tiering: hot page selection with hint page fault latencyHuang Ying3-0/+101
Patch series "memory tiering: hot page selection", v4. To optimize page placement in a memory tiering system with NUMA balancing, the hot pages in the slow memory nodes need to be identified. Essentially, the original NUMA balancing implementation selects the mostly recently accessed (MRU) pages to promote. But this isn't a perfect algorithm to identify the hot pages. Because the pages with quite low access frequency may be accessed eventually given the NUMA balancing page table scanning period could be quite long (e.g. 60 seconds). So in this patchset, we implement a new hot page identification algorithm based on the latency between NUMA balancing page table scanning and hint page fault. Which is a kind of mostly frequently accessed (MFU) algorithm. In NUMA balancing memory tiering mode, if there are hot pages in slow memory node and cold pages in fast memory node, we need to promote/demote hot/cold pages between the fast and cold memory nodes. A choice is to promote/demote as fast as possible. But the CPU cycles and memory bandwidth consumed by the high promoting/demoting throughput will hurt the latency of some workload because of accessing inflating and slow memory bandwidth contention. A way to resolve this issue is to restrict the max promoting/demoting throughput. It will take longer to finish the promoting/demoting. But the workload latency will be better. This is implemented in this patchset as the page promotion rate limit mechanism. The promotion hot threshold is workload and system configuration dependent. So in this patchset, a method to adjust the hot threshold automatically is implemented. The basic idea is to control the number of the candidate promotion pages to match the promotion rate limit. We used the pmbench memory accessing benchmark tested the patchset on a 2-socket server system with DRAM and PMEM installed. The test results are as follows, pmbench score promote rate (accesses/s) MB/s ------------- ------------ base 146887704.1 725.6 hot selection 165695601.2 544.0 rate limit 162814569.8 165.2 auto adjustment 170495294.0 136.9 From the results above, With hot page selection patch [1/3], the pmbench score increases about 12.8%, and promote rate (overhead) decreases about 25.0%, compared with base kernel. With rate limit patch [2/3], pmbench score decreases about 1.7%, and promote rate decreases about 69.6%, compared with hot page selection patch. With threshold auto adjustment patch [3/3], pmbench score increases about 4.7%, and promote rate decrease about 17.1%, compared with rate limit patch. Baolin helped to test the patchset with MySQL on a machine which contains 1 DRAM node (30G) and 1 PMEM node (126G). sysbench /usr/share/sysbench/oltp_read_write.lua \ ...... --tables=200 \ --table-size=1000000 \ --report-interval=10 \ --threads=16 \ --time=120 The tps can be improved about 5%. This patch (of 3): To optimize page placement in a memory tiering system with NUMA balancing, the hot pages in the slow memory node need to be identified. Essentially, the original NUMA balancing implementation selects the mostly recently accessed (MRU) pages to promote. But this isn't a perfect algorithm to identify the hot pages. Because the pages with quite low access frequency may be accessed eventually given the NUMA balancing page table scanning period could be quite long (e.g. 60 seconds). The most frequently accessed (MFU) algorithm is better. So, in this patch we implemented a better hot page selection algorithm. Which is based on NUMA balancing page table scanning and hint page fault as follows, - When the page tables of the processes are scanned to change PTE/PMD to be PROT_NONE, the current time is recorded in struct page as scan time. - When the page is accessed, hint page fault will occur. The scan time is gotten from the struct page. And The hint page fault latency is defined as hint page fault time - scan time The shorter the hint page fault latency of a page is, the higher the probability of their access frequency to be higher. So the hint page fault latency is a better estimation of the page hot/cold. It's hard to find some extra space in struct page to hold the scan time. Fortunately, we can reuse some bits used by the original NUMA balancing. NUMA balancing uses some bits in struct page to store the page accessing CPU and PID (referring to page_cpupid_xchg_last()). Which is used by the multi-stage node selection algorithm to avoid to migrate pages shared accessed by the NUMA nodes back and forth. But for pages in the slow memory node, even if they are shared accessed by multiple NUMA nodes, as long as the pages are hot, they need to be promoted to the fast memory node. So the accessing CPU and PID information are unnecessary for the slow memory pages. We can reuse these bits in struct page to record the scan time. For the fast memory pages, these bits are used as before. For the hot threshold, the default value is 1 second, which works well in our performance test. All pages with hint page fault latency < hot threshold will be considered hot. It's hard for users to determine the hot threshold. So we don't provide a kernel ABI to set it, just provide a debugfs interface for advanced users to experiment. We will continue to work on a hot threshold automatic adjustment mechanism. The downside of the above method is that the response time to the workload hot spot changing may be much longer. For example, - A previous cold memory area becomes hot - The hint page fault will be triggered. But the hint page fault latency isn't shorter than the hot threshold. So the pages will not be promoted. - When the memory area is scanned again, maybe after a scan period, the hint page fault latency measured will be shorter than the hot threshold and the pages will be promoted. To mitigate this, if there are enough free space in the fast memory node, the hot threshold will not be used, all pages will be promoted upon the hint page fault for fast response. Thanks Zhong Jiang reported and tested the fix for a bug when disabling memory tiering mode dynamically. Link: https://lkml.kernel.org/r/20220713083954.34196-1-ying.huang@intel.com Link: https://lkml.kernel.org/r/20220713083954.34196-2-ying.huang@intel.com Signed-off-by: "Huang, Ying" <ying.huang@intel.com> Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com> Tested-by: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Rik van Riel <riel@surriel.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Yang Shi <shy828301@gmail.com> Cc: Zi Yan <ziy@nvidia.com> Cc: Wei Xu <weixugc@google.com> Cc: osalvador <osalvador@suse.de> Cc: Shakeel Butt <shakeelb@google.com> Cc: Zhong Jiang <zhongjiang-ali@linux.alibaba.com> Cc: Oscar Salvador <osalvador@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-09-09Merge tag 'driver-core-6.0-rc5' of ↵Linus Torvalds1-1/+1
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core Pull driver core fixes from Greg KH: "Here are some small driver core and debugfs fixes for 6.0-rc5. Included in here are: - multiple attempts to get the arch_topology code to work properly on non-cluster SMT systems. First attempt caused build breakages in linux-next and 0-day, second try worked. - debugfs fixes for a long-suffering memory leak. The pattern of debugfs_remove(debugfs_lookup(...)) turns out to leak dentries, so add debugfs_lookup_and_remove() to fix this problem. Also fix up the scheduler debug code that highlighted this problem. Fixes for other subsystems will be trickling in over the next few months for this same issue once the debugfs function is merged. All of these have been in linux-next since Wednesday with no reported problems" * tag 'driver-core-6.0-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: arch_topology: Make cluster topology span at least SMT CPUs sched/debug: fix dentry leak in update_sched_domain_debugfs debugfs: add debugfs_lookup_and_remove() driver core: fix driver_set_override() issue with empty strings Revert "arch_topology: Make cluster topology span at least SMT CPUs" arch_topology: Make cluster topology span at least SMT CPUs
2022-09-09sched/psi: Per-cgroup PSI accounting disable/re-enable interfaceChengming Zhou1-7/+63
PSI accounts stalls for each cgroup separately and aggregates it at each level of the hierarchy. This may cause non-negligible overhead for some workloads when under deep level of the hierarchy. commit 3958e2d0c34e ("cgroup: make per-cgroup pressure stall tracking configurable") make PSI to skip per-cgroup stall accounting, only account system-wide to avoid this each level overhead. But for our use case, we also want leaf cgroup PSI stats accounted for userspace adjustment on that cgroup, apart from only system-wide adjustment. So this patch introduce a per-cgroup PSI accounting disable/re-enable interface "cgroup.pressure", which is a read-write single value file that allowed values are "0" and "1", the defaults is "1" so per-cgroup PSI stats is enabled by default. Implementation details: It should be relatively straight-forward to disable and re-enable state aggregation, time tracking, averaging on a per-cgroup level, if we can live with losing history from while it was disabled. I.e. the avgs will restart from 0, total= will have gaps. But it's hard or complex to stop/restart groupc->tasks[] updates, which is not implemented in this patch. So we always update groupc->tasks[] and PSI_ONCPU bit in psi_group_change() even when the cgroup PSI stats is disabled. Suggested-by: Johannes Weiner <hannes@cmpxchg.org> Suggested-by: Tejun Heo <tj@kernel.org> Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Link: https://lkml.kernel.org/r/20220907090332.2078-1-zhouchengming@bytedance.com
2022-09-09sched/psi: Cache parent psi_group to speed up group iterationChengming Zhou1-30/+19
We use iterate_groups() to iterate each level psi_group to update PSI stats, which is a very hot path. In current code, iterate_groups() have to use multiple branches and cgroup_parent() to get parent psi_group for each level, which is not very efficient. This patch cache parent psi_group in struct psi_group, only need to get psi_group of task itself first, then just use group->parent to iterate. Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Link: https://lore.kernel.org/r/20220825164111.29534-10-zhouchengming@bytedance.com
2022-09-09sched/psi: Add PSI_IRQ to track IRQ/SOFTIRQ pressureChengming Zhou3-2/+75
Now PSI already tracked workload pressure stall information for CPU, memory and IO. Apart from these, IRQ/SOFTIRQ could have obvious impact on some workload productivity, such as web service workload. When CONFIG_IRQ_TIME_ACCOUNTING, we can get IRQ/SOFTIRQ delta time from update_rq_clock_task(), in which we can record that delta to CPU curr task's cgroups as PSI_IRQ_FULL status. Note we don't use PSI_IRQ_SOME since IRQ/SOFTIRQ always happen in the current task on the CPU, make nothing productive could run even if it were runnable, so we only use PSI_IRQ_FULL. Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Link: https://lore.kernel.org/r/20220825164111.29534-8-zhouchengming@bytedance.com
2022-09-09sched/psi: Remove NR_ONCPU task accountingJohannes Weiner1-11/+30
We put all fields updated by the scheduler in the first cacheline of struct psi_group_cpu for performance. Since we want add another PSI_IRQ_FULL to track IRQ/SOFTIRQ pressure, we need to reclaim space first. This patch remove NR_ONCPU task accounting in struct psi_group_cpu, use one bit in state_mask to track instead. Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Chengming Zhou <zhouchengming@bytedance.com> Tested-by: Chengming Zhou <zhouchengming@bytedance.com> Link: https://lore.kernel.org/r/20220825164111.29534-7-zhouchengming@bytedance.com
2022-09-09sched/psi: Optimize task switch inside shared cgroups againChengming Zhou1-12/+9
Way back when PSI_MEM_FULL was accounted from the timer tick, task switching could simply iterate next and prev to the common ancestor to update TSK_ONCPU and be done. Then memstall ticks were replaced with checking curr->in_memstall directly in psi_group_change(). That meant that now if the task switch was between a memstall and a !memstall task, we had to iterate through the common ancestors at least ONCE to fix up their state_masks. We added the identical_state filter to make sure the common ancestor elimination was skipped in that case. It seems that was always a little too eager, because it caused us to walk the common ancestors *twice* instead of the required once: the iteration for next could have stopped at the common ancestor; prev could have updated TSK_ONCPU up to the common ancestor, then finish to the root without changing any flags, just to get the new curr->in_memstall into the state_masks. This patch recognizes this and makes it so that we walk to the root exactly once if state_mask needs updating, which is simply catching up on a missed optimization that could have been done in commit 7fae6c8171d2 ("psi: Use ONCPU state tracking machinery to detect reclaim") directly. Apart from this, it's also necessary for the next patch "sched/psi: remove NR_ONCPU task accounting". Suppose we walk the common ancestors twice: (1) psi_group_change(.clear = 0, .set = TSK_ONCPU) (2) psi_group_change(.clear = TSK_ONCPU, .set = 0) We previously used tasks[NR_ONCPU] to record TSK_ONCPU, tasks[NR_ONCPU]++ in (1) then tasks[NR_ONCPU]-- in (2), so tasks[NR_ONCPU] still be correct. The next patch change to use one bit in state mask to record TSK_ONCPU, PSI_ONCPU bit will be set in (1), but then be cleared in (2), which cause the psi_group_cpu has task running on CPU but without PSI_ONCPU bit set! With this patch, we will never walk the common ancestors twice, so won't have above problem. Suggested-by: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Link: https://lore.kernel.org/r/20220825164111.29534-6-zhouchengming@bytedance.com
2022-09-09sched/psi: Move private helpers to sched/stats.hChengming Zhou1-0/+4
This patch move psi_task_change/psi_task_switch declarations out of PSI public header, since they are only needed for implementing the PSI stats tracking in sched/stats.h psi_task_switch is obvious, psi_task_change can't be public helper since it doesn't check psi_disabled static key. And there is no any user now, so put it in sched/stats.h too. Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Link: https://lore.kernel.org/r/20220825164111.29534-5-zhouchengming@bytedance.com
2022-09-09sched/psi: Save percpu memory when !psi_cgroups_enabledChengming Zhou1-3/+4
We won't use cgroup psi_group when !psi_cgroups_enabled, so don't bother to alloc percpu memory and init for it. Also don't need to migrate task PSI stats between cgroups in cgroup_move_task(). Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Link: https://lore.kernel.org/r/20220825164111.29534-4-zhouchengming@bytedance.com
2022-09-09sched/psi: Fix periodic aggregation shut offChengming Zhou1-14/+14
We don't want to wake periodic aggregation work back up if the task change is the aggregation worker itself going to sleep, or we'll ping-pong forever. Previously, we would use psi_task_change() in psi_dequeue() when task going to sleep, so this check was put in psi_task_change(). But commit 4117cebf1a9f ("psi: Optimize task switch inside shared cgroups") defer task sleep handling to psi_task_switch(), won't go through psi_task_change() anymore. So this patch move this check to psi_task_switch(). Fixes: 4117cebf1a9f ("psi: Optimize task switch inside shared cgroups") Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Link: https://lore.kernel.org/r/20220825164111.29534-2-zhouchengming@bytedance.com
2022-09-07freezer,sched: Rewrite core freezer logicPeter Zijlstra1-1/+1
Rewrite the core freezer to behave better wrt thawing and be simpler in general. By replacing PF_FROZEN with TASK_FROZEN, a special block state, it is ensured frozen tasks stay frozen until thawed and don't randomly wake up early, as is currently possible. As such, it does away with PF_FROZEN and PF_FREEZER_SKIP, freeing up two PF_flags (yay!). Specifically; the current scheme works a little like: freezer_do_not_count(); schedule(); freezer_count(); And either the task is blocked, or it lands in try_to_freezer() through freezer_count(). Now, when it is blocked, the freezer considers it frozen and continues. However, on thawing, once pm_freezing is cleared, freezer_count() stops working, and any random/spurious wakeup will let a task run before its time. That is, thawing tries to thaw things in explicit order; kernel threads and workqueues before doing bringing SMP back before userspace etc.. However due to the above mentioned races it is entirely possible for userspace tasks to thaw (by accident) before SMP is back. This can be a fatal problem in asymmetric ISA architectures (eg ARMv9) where the userspace task requires a special CPU to run. As said; replace this with a special task state TASK_FROZEN and add the following state transitions: TASK_FREEZABLE -> TASK_FROZEN __TASK_STOPPED -> TASK_FROZEN __TASK_TRACED -> TASK_FROZEN The new TASK_FREEZABLE can be set on any state part of TASK_NORMAL (IOW. TASK_INTERRUPTIBLE and TASK_UNINTERRUPTIBLE) -- any such state is already required to deal with spurious wakeups and the freezer causes one such when thawing the task (since the original state is lost). The special __TASK_{STOPPED,TRACED} states *can* be restored since their canonical state is in ->jobctl. With this, frozen tasks need an explicit TASK_FROZEN wakeup and are free of undue (early / spurious) wakeups. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Ingo Molnar <mingo@kernel.org> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Link: https://lore.kernel.org/r/20220822114649.055452969@infradead.org
2022-09-07sched/completion: Add wait_for_completion_state()Peter Zijlstra1-0/+12
Allows waiting with a custom @state. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/20220822114648.922711674@infradead.org
2022-09-07sched: Add TASK_ANY for wait_task_inactive()Peter Zijlstra1-8/+8
Now that wait_task_inactive()'s @match_state argument is a mask (like ttwu()) it is possible to replace the special !match_state case with an 'all-states' value such that any blocked state will match. Suggested-by: Ingo Molnar (mingo@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/YxhkzfuFTvRnpUaH@hirez.programming.kicks-ass.net
2022-09-07sched: Change wait_task_inactive()s match_statePeter Zijlstra1-2/+2
Make wait_task_inactive()'s @match_state work like ttwu()'s @state. That is, instead of an equal comparison, use it as a mask. This allows matching multiple block conditions. (removes the unlikely; it doesn't make sense how it's only part of the condition) Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20220822114648.856734578@infradead.org
2022-09-07sched: Rename task_running() to task_on_cpu()Peter Zijlstra6-14/+14
There is some ambiguity about task_running() in that it is unrelated to TASK_RUNNING but instead tests ->on_cpu. As such, rename the thing task_on_cpu(). Suggested-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/Yxhkhn55uHZx+NGl@hirez.programming.kicks-ass.net
2022-09-07sched/fair: Cleanup for SIS_PROPAbel Wu1-6/+6
The sched-domain of this cpu is only used for some heuristics when SIS_PROP is enabled, and it should be irrelevant whether the local sd_llc is valid or not, since all we care about is target sd_llc if !SIS_PROP. Access the local domain only when there is a need. Signed-off-by: Abel Wu <wuyun.abel@bytedance.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Mel Gorman <mgorman@suse.de> Link: https://lore.kernel.org/r/20220907112000.1854-6-wuyun.abel@bytedance.com
2022-09-07sched/fair: Default to false in test_idle_cores()Abel Wu1-8/+8
It's uncertain whether idle cores exist or not if shared sched- domains are not ready, so returning "no idle cores" usually makes sense. While __update_idle_core() is an exception, it checks status of this core and set hint to shared sched-domain if necessary. So the whole logic of this function depends on the existence of shared sched-domain, and can certainly bail out early if it is not available. It's somehow a little tricky, and as Josh suggested that it should be transient while the domain isn't ready. So remove the self-defined default value to make things more clearer. Signed-off-by: Abel Wu <wuyun.abel@bytedance.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Josh Don <joshdon@google.com> Acked-by: Mel Gorman <mgorman@techsingularity.net> Link: https://lore.kernel.org/r/20220907112000.1854-5-wuyun.abel@bytedance.com
2022-09-07sched/fair: Remove useless check in select_idle_core()Abel Wu1-3/+0
The function select_idle_core() only gets called when has_idle_cores is true which can be possible only when sched_smt_present is enabled. This change also aligns select_idle_core() with select_idle_smt() in the way that the caller do the check if necessary. Signed-off-by: Abel Wu <wuyun.abel@bytedance.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Mel Gorman <mgorman@techsingularity.net> Link: https://lore.kernel.org/r/20220907112000.1854-4-wuyun.abel@bytedance.com
2022-09-07sched/fair: Avoid double search on same cpuAbel Wu1-0/+2
The prev cpu is checked at the beginning of SIS, and it's unlikely to be idle before the second check in select_idle_smt(). So we'd better focus on its SMT siblings. Signed-off-by: Abel Wu <wuyun.abel@bytedance.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Josh Don <joshdon@google.com> Acked-by: Mel Gorman <mgorman@techsingularity.net> Link: https://lore.kernel.org/r/20220907112000.1854-3-wuyun.abel@bytedance.com
2022-09-07sched/fair: Remove redundant check in select_idle_smt()Abel Wu1-7/+4
If two cpus share LLC cache, then the two cores they belong to are also in the same LLC domain. Signed-off-by: Abel Wu <wuyun.abel@bytedance.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Josh Don <joshdon@google.com> Acked-by: Mel Gorman <mgorman@techsingularity.net> Link: https://lore.kernel.org/r/20220907112000.1854-2-wuyun.abel@bytedance.com
2022-09-05sched/debug: fix dentry leak in update_sched_domain_debugfsGreg Kroah-Hartman1-1/+1
Kuyo reports that the pattern of using debugfs_remove(debugfs_lookup()) leaks a dentry and with a hotplug stress test, the machine eventually runs out of memory. Fix this up by using the newly created debugfs_lookup_and_remove() call instead which properly handles the dentry reference counting logic. Cc: Major Chen <major.chen@samsung.com> Cc: stable <stable@kernel.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Juri Lelli <juri.lelli@redhat.com> Cc: Vincent Guittot <vincent.guittot@linaro.org> Cc: Dietmar Eggemann <dietmar.eggemann@arm.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Ben Segall <bsegall@google.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Daniel Bristot de Oliveira <bristot@redhat.com> Cc: Valentin Schneider <vschneid@redhat.com> Cc: Matthias Brugger <matthias.bgg@gmail.com> Reported-by: Kuyo Chang <kuyo.chang@mediatek.com> Tested-by: Kuyo Chang <kuyo.chang@mediatek.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20220902123107.109274-2-gregkh@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-09-01sched/deadline: Move __dl_clear_params out of dl_bw lockShang XiaoJing1-1/+1
As members in sched_dl_entity are independent with dl_bw, move __dl_clear_params out of dl_bw lock. Signed-off-by: Shang XiaoJing <shangxiaojing@huawei.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Daniel Bristot de Oliveira <bristot@kernel.org> Link: https://lore.kernel.org/r/20220827020911.30641-1-shangxiaojing@huawei.com
2022-09-01sched/deadline: Add replenish_dl_new_period helperShang XiaoJing1-10/+13
Wrap repeated code in helper function replenish_dl_new_period, which set the deadline and runtime of input dl_se based on pi_of(dl_se). Note that setup_new_dl_entity originally set the deadline and runtime base on dl_se, which should equals to pi_of(dl_se) for non-boosted task. Signed-off-by: Shang XiaoJing <shangxiaojing@huawei.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Daniel Bristot de Oliveira <bristot@kernel.org> Link: https://lore.kernel.org/r/20220826100037.12146-1-shangxiaojing@huawei.com
2022-09-01sched/deadline: Add dl_task_is_earliest_deadline helperShang XiaoJing1-12/+12
Wrap repeated code in helper function dl_task_is_earliest_deadline, which return true if there is no deadline task on the rq at all, or task's deadline earlier than the whole rq. Signed-off-by: Shang XiaoJing <shangxiaojing@huawei.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Daniel Bristot de Oliveira <bristot@kernel.org> Link: https://lore.kernel.org/r/20220826083453.698-1-shangxiaojing@huawei.com
2022-08-31sched/debug: Show the registers of 'current' in dump_cpu_task()Zhen Lei1-0/+11
The dump_cpu_task() function does not print registers on architectures that do not support NMIs. However, registers can be useful for debugging. Fortunately, in the case where dump_cpu_task() is invoked from an interrupt handler and is dumping the current CPU's stack, the get_irq_regs() function can be used to get the registers. Therefore, this commit makes dump_cpu_task() check to see if it is being asked to dump the current CPU's stack from within an interrupt handler, and, if so, it uses the get_irq_regs() function to obtain the registers. On systems that do support NMIs, this commit has the further advantage of avoiding a self-NMI in this case. This is an example of rcu self-detected stall on arm64, which does not support NMIs: [ 27.501721] rcu: INFO: rcu_preempt self-detected stall on CPU [ 27.502238] rcu: 0-....: (1250 ticks this GP) idle=4f7/1/0x4000000000000000 softirq=2594/2594 fqs=619 [ 27.502632] (t=1251 jiffies g=2989 q=29 ncpus=4) [ 27.503845] CPU: 0 PID: 306 Comm: test0 Not tainted 5.19.0-rc7-00009-g1c1a6c29ff99-dirty #46 [ 27.504732] Hardware name: linux,dummy-virt (DT) [ 27.504947] pstate: 20000005 (nzCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ 27.504998] pc : arch_counter_read+0x18/0x24 [ 27.505301] lr : arch_counter_read+0x18/0x24 [ 27.505328] sp : ffff80000b29bdf0 [ 27.505345] x29: ffff80000b29bdf0 x28: 0000000000000000 x27: 0000000000000000 [ 27.505475] x26: 0000000000000000 x25: 0000000000000000 x24: 0000000000000000 [ 27.505553] x23: 0000000000001f40 x22: ffff800009849c48 x21: 000000065f871ae0 [ 27.505627] x20: 00000000000025ec x19: ffff80000a6eb300 x18: ffffffffffffffff [ 27.505654] x17: 0000000000000001 x16: 0000000000000000 x15: ffff80000a6d0296 [ 27.505681] x14: ffffffffffffffff x13: ffff80000a29bc18 x12: 0000000000000426 [ 27.505709] x11: 0000000000000162 x10: ffff80000a2f3c18 x9 : ffff80000a29bc18 [ 27.505736] x8 : 00000000ffffefff x7 : ffff80000a2f3c18 x6 : 00000000759bd013 [ 27.505761] x5 : 01ffffffffffffff x4 : 0002dc6c00000000 x3 : 0000000000000017 [ 27.505787] x2 : 00000000000025ec x1 : ffff80000b29bdf0 x0 : 0000000075a30653 [ 27.505937] Call trace: [ 27.506002] arch_counter_read+0x18/0x24 [ 27.506171] ktime_get+0x48/0xa0 [ 27.506207] test_task+0x70/0xf0 [ 27.506227] kthread+0x10c/0x110 [ 27.506243] ret_from_fork+0x10/0x20 This is a marked improvement over the old output: [ 27.944550] rcu: INFO: rcu_preempt self-detected stall on CPU [ 27.944980] rcu: 0-....: (1249 ticks this GP) idle=cbb/1/0x4000000000000000 softirq=2610/2610 fqs=614 [ 27.945407] (t=1251 jiffies g=2681 q=28 ncpus=4) [ 27.945731] Task dump for CPU 0: [ 27.945844] task:test0 state:R running task stack: 0 pid: 306 ppid: 2 flags:0x0000000a [ 27.946073] Call trace: [ 27.946151] dump_backtrace.part.0+0xc8/0xd4 [ 27.946378] show_stack+0x18/0x70 [ 27.946405] sched_show_task+0x150/0x180 [ 27.946427] dump_cpu_task+0x44/0x54 [ 27.947193] rcu_dump_cpu_stacks+0xec/0x130 [ 27.947212] rcu_sched_clock_irq+0xb18/0xef0 [ 27.947231] update_process_times+0x68/0xac [ 27.947248] tick_sched_handle+0x34/0x60 [ 27.947266] tick_sched_timer+0x4c/0xa4 [ 27.947281] __hrtimer_run_queues+0x178/0x360 [ 27.947295] hrtimer_interrupt+0xe8/0x244 [ 27.947309] arch_timer_handler_virt+0x38/0x4c [ 27.947326] handle_percpu_devid_irq+0x88/0x230 [ 27.947342] generic_handle_domain_irq+0x2c/0x44 [ 27.947357] gic_handle_irq+0x44/0xc4 [ 27.947376] call_on_irq_stack+0x2c/0x54 [ 27.947415] do_interrupt_handler+0x80/0x94 [ 27.947431] el1_interrupt+0x34/0x70 [ 27.947447] el1h_64_irq_handler+0x18/0x24 [ 27.947462] el1h_64_irq+0x64/0x68 <--- the above backtrace is worthless [ 27.947474] arch_counter_read+0x18/0x24 [ 27.947487] ktime_get+0x48/0xa0 [ 27.947501] test_task+0x70/0xf0 [ 27.947520] kthread+0x10c/0x110 [ 27.947538] ret_from_fork+0x10/0x20 Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Juri Lelli <juri.lelli@redhat.com> Cc: Vincent Guittot <vincent.guittot@linaro.org> Cc: Dietmar Eggemann <dietmar.eggemann@arm.com> Cc: Ben Segall <bsegall@google.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Daniel Bristot de Oliveira <bristot@redhat.com> Cc: Valentin Schneider <vschneid@redhat.com>
2022-08-31sched/debug: Try trigger_single_cpu_backtrace(cpu) in dump_cpu_task()Zhen Lei1-0/+3
The trigger_all_cpu_backtrace() function attempts to send an NMI to the target CPU, which usually provides much better stack traces than the dump_cpu_task() function's approach of dumping that stack from some other CPU. So much so that most calls to dump_cpu_task() only happen after a call to trigger_all_cpu_backtrace() has failed. And the exception to this rule really should attempt to use trigger_all_cpu_backtrace() first. Therefore, move the trigger_all_cpu_backtrace() invocation into dump_cpu_task(). Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Juri Lelli <juri.lelli@redhat.com> Cc: Vincent Guittot <vincent.guittot@linaro.org> Cc: Dietmar Eggemann <dietmar.eggemann@arm.com> Cc: Ben Segall <bsegall@google.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Daniel Bristot de Oliveira <bristot@redhat.com> Cc: Valentin Schneider <vschneid@redhat.com>
2022-08-30Merge branch 'sched/warnings' into sched/core, to pick up WARN_ON_ONCE() ↵Ingo Molnar9-46/+94
conversion commit Merge in the BUG_ON() => WARN_ON_ONCE() conversion commit. Signed-off-by: Ingo Molnar <mingo@kernel.org>
2022-08-27sched: Add update_current_exec_runtime helperShang XiaoJing4-17/+16
Wrap repeated code in helper function update_current_exec_runtime for update the exec time of the current. Signed-off-by: Shang XiaoJing <shangxiaojing@huawei.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20220824082856.15674-1-shangxiaojing@huawei.com
2022-08-26wait_on_bit: add an acquire memory barrierMikulas Patocka1-1/+1
There are several places in the kernel where wait_on_bit is not followed by a memory barrier (for example, in drivers/md/dm-bufio.c:new_read). On architectures with weak memory ordering, it may happen that memory accesses that follow wait_on_bit are reordered before wait_on_bit and they may return invalid data. Fix this class of bugs by introducing a new function "test_bit_acquire" that works like test_bit, but has acquire memory ordering semantics. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Acked-by: Will Deacon <will@kernel.org> Cc: stable@vger.kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>