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2022-06-03Merge tag 'ptrace_stop-cleanup-for-v5.19' of ↵Linus Torvalds1-4/+1
git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace Pull ptrace_stop cleanups from Eric Biederman: "While looking at the ptrace problems with PREEMPT_RT and the problems Peter Zijlstra was encountering with ptrace in his freezer rewrite I identified some cleanups to ptrace_stop that make sense on their own and move make resolving the other problems much simpler. The biggest issue is the habit of the ptrace code to change task->__state from the tracer to suppress TASK_WAKEKILL from waking up the tracee. No other code in the kernel does that and it is straight forward to update signal_wake_up and friends to make that unnecessary. Peter's task freezer sets frozen tasks to a new state TASK_FROZEN and then it stores them by calling "wake_up_state(t, TASK_FROZEN)" relying on the fact that all stopped states except the special stop states can tolerate spurious wake up and recover their state. The state of stopped and traced tasked is changed to be stored in task->jobctl as well as in task->__state. This makes it possible for the freezer to recover tasks in these special states, as well as serving as a general cleanup. With a little more work in that direction I believe TASK_STOPPED can learn to tolerate spurious wake ups and become an ordinary stop state. The TASK_TRACED state has to remain a special state as the registers for a process are only reliably available when the process is stopped in the scheduler. Fundamentally ptrace needs acess to the saved register values of a task. There are bunch of semi-random ptrace related cleanups that were found while looking at these issues. One cleanup that deserves to be called out is from commit 57b6de08b5f6 ("ptrace: Admit ptrace_stop can generate spuriuos SIGTRAPs"). This makes a change that is technically user space visible, in the handling of what happens to a tracee when a tracer dies unexpectedly. According to our testing and our understanding of userspace nothing cares that spurious SIGTRAPs can be generated in that case" * tag 'ptrace_stop-cleanup-for-v5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: sched,signal,ptrace: Rework TASK_TRACED, TASK_STOPPED state ptrace: Always take siglock in ptrace_resume ptrace: Don't change __state ptrace: Admit ptrace_stop can generate spuriuos SIGTRAPs ptrace: Document that wait_task_inactive can't fail ptrace: Reimplement PTRACE_KILL by always sending SIGKILL signal: Use lockdep_assert_held instead of assert_spin_locked ptrace: Remove arch_ptrace_attach ptrace/xtensa: Replace PT_SINGLESTEP with TIF_SINGLESTEP ptrace/um: Replace PT_DTRACE with TIF_SINGLESTEP signal: Replace __group_send_sig_info with send_signal_locked signal: Rename send_signal send_signal_locked
2022-05-26Merge tag 'sysctl-5.19-rc1' of ↵Linus Torvalds1-45/+85
git://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux 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 ...
2022-05-24Merge tag 'sched-core-2022-05-23' of ↵Linus Torvalds1-10/+13
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull scheduler updates from Ingo Molnar: - Updates to scheduler metrics: - PELT fixes & enhancements - PSI fixes & enhancements - Refactor cpu_util_without() - Updates to instrumentation/debugging: - Remove sched_trace_*() helper functions - can be done via debug info - Fix double update_rq_clock() warnings - Introduce & use "preemption model accessors" to simplify some of the Kconfig complexity. - Make softirq handling RT-safe. - Misc smaller fixes & cleanups. * tag 'sched-core-2022-05-23' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: topology: Remove unused cpu_cluster_mask() sched: Reverse sched_class layout sched/deadline: Remove superfluous rq clock update in push_dl_task() sched/core: Avoid obvious double update_rq_clock warning smp: Make softirq handling RT safe in flush_smp_call_function_queue() smp: Rename flush_smp_call_function_from_idle() sched: Fix missing prototype warnings sched/fair: Remove cfs_rq_tg_path() sched/fair: Remove sched_trace_*() helper functions sched/fair: Refactor cpu_util_without() sched/fair: Revise comment about lb decision matrix sched/psi: report zeroes for CPU full at the system level sched/fair: Delete useless condition in tg_unthrottle_up() sched/fair: Fix cfs_rq_clock_pelt() for throttled cfs_rq sched/fair: Move calculate of avg_load to a better location mailmap: Update my email address to @redhat.com MAINTAINERS: Add myself as scheduler topology reviewer psi: Fix trigger being fired unexpectedly at initial ftrace: Use preemption model accessors for trace header printout kcsan: Use preemption model accessors
2022-05-23Merge tag 'rcu.2022.05.19a' of ↵Linus Torvalds1-0/+12
git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu Pull RCU update from Paul McKenney: - Documentation updates - Miscellaneous fixes - Callback-offloading updates, mainly simplifications - RCU-tasks updates, including some -rt fixups, handling of systems with sparse CPU numbering, and a fix for a boot-time race-condition failure - Put SRCU on a memory diet in order to reduce the size of the srcu_struct structure - Torture-test updates fixing some bugs in tests and closing some testing holes - Torture-test updates for the RCU tasks flavors, most notably ensuring that building rcutorture and friends does not change the RCU-tasks-related Kconfig options - Torture-test scripting updates - Expedited grace-period updates, most notably providing milliseconds-scale (not all that) soft real-time response from synchronize_rcu_expedited(). This is also the first time in almost 30 years of RCU that someone other than me has pushed for a reduction in the RCU CPU stall-warning timeout, in this case by more than three orders of magnitude from 21 seconds to 20 milliseconds. This tighter timeout applies only to expedited grace periods * tag 'rcu.2022.05.19a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu: (80 commits) rcu: Move expedited grace period (GP) work to RT kthread_worker rcu: Introduce CONFIG_RCU_EXP_CPU_STALL_TIMEOUT srcu: Drop needless initialization of sdp in srcu_gp_start() srcu: Prevent expedited GPs and blocking readers from consuming CPU srcu: Add contention check to call_srcu() srcu_data ->lock acquisition srcu: Automatically determine size-transition strategy at boot rcutorture: Make torture.sh allow for --kasan rcutorture: Make torture.sh refscale and rcuscale specify Tasks Trace RCU rcutorture: Make kvm.sh allow more memory for --kasan runs torture: Save "make allmodconfig" .config file scftorture: Remove extraneous "scf" from per_version_boot_params rcutorture: Adjust scenarios' Kconfig options for CONFIG_PREEMPT_DYNAMIC torture: Enable CSD-lock stall reports for scftorture torture: Skip vmlinux check for kvm-again.sh runs scftorture: Adjust for TASKS_RCU Kconfig option being selected rcuscale: Allow rcuscale without RCU Tasks Rude/Trace rcuscale: Allow rcuscale without RCU Tasks refscale: Allow refscale without RCU Tasks Rude/Trace refscale: Allow refscale without RCU Tasks rcutorture: Allow specifying per-scenario stat_interval ...
2022-05-19sched: Reverse sched_class layoutPeter Zijlstra1-6/+6
Because GCC-12 is fully stupid about array bounds and it's just really hard to get a solid array definition from a linker script, flip the array order to avoid needing negative offsets :-/ This makes the whole relational pointer magic a little less obvious, but alas. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Kees Cook <keescook@chromium.org> Link: https://lkml.kernel.org/r/YoOLLmLG7HRTXeEm@hirez.programming.kicks-ass.net
2022-05-12sched/tracing: Append prev_state to tp args insteadDelyan Kratunov1-1/+1
Commit fa2c3254d7cf (sched/tracing: Don't re-read p->state when emitting sched_switch event, 2022-01-20) added a new prev_state argument to the sched_switch tracepoint, before the prev task_struct pointer. This reordering of arguments broke BPF programs that use the raw tracepoint (e.g. tp_btf programs). The type of the second argument has changed and existing programs that assume a task_struct* argument (e.g. for bpf_task_storage access) will now fail to verify. If we instead append the new argument to the end, all existing programs would continue to work and can conditionally extract the prev_state argument on supported kernel versions. Fixes: fa2c3254d7cf (sched/tracing: Don't re-read p->state when emitting sched_switch event, 2022-01-20) Signed-off-by: Delyan Kratunov <delyank@fb.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org> Link: https://lkml.kernel.org/r/c8a6930dfdd58a4a5755fc01732675472979732b.camel@fb.com
2022-05-11ptrace: Don't change __stateEric W. Biederman1-4/+1
Stop playing with tsk->__state to remove TASK_WAKEKILL while a ptrace command is executing. Instead remove TASK_WAKEKILL from the definition of TASK_TRACED, and implement a new jobctl flag TASK_PTRACE_FROZEN. This new flag is set in jobctl_freeze_task and cleared when ptrace_stop is awoken or in jobctl_unfreeze_task (when ptrace_stop remains asleep). In signal_wake_up add __TASK_TRACED to state along with TASK_WAKEKILL when the wake up is for a fatal signal. Skip adding __TASK_TRACED when TASK_PTRACE_FROZEN is not set. This has the same effect as changing TASK_TRACED to __TASK_TRACED as all of the wake_ups that use TASK_KILLABLE go through signal_wake_up. Handle a ptrace_stop being called with a pending fatal signal. Previously it would have been handled by schedule simply failing to sleep. As TASK_WAKEKILL is no longer part of TASK_TRACED schedule will sleep with a fatal_signal_pending. The code in signal_wake_up guarantees that the code will be awaked by any fatal signal that codes after TASK_TRACED is set. Previously the __state value of __TASK_TRACED was changed to TASK_RUNNING when woken up or back to TASK_TRACED when the code was left in ptrace_stop. Now when woken up ptrace_stop now clears JOBCTL_PTRACE_FROZEN and when left sleeping ptrace_unfreezed_traced clears JOBCTL_PTRACE_FROZEN. Tested-by: Kees Cook <keescook@chromium.org> Reviewed-by: Oleg Nesterov <oleg@redhat.com> Link: https://lkml.kernel.org/r/20220505182645.497868-10-ebiederm@xmission.com Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2022-05-11sched/core: Avoid obvious double update_rq_clock warningHao Jia1-3/+3
When we use raw_spin_rq_lock() to acquire the rq lock and have to update the rq clock while holding the lock, the kernel may issue a WARN_DOUBLE_CLOCK warning. Since we directly use raw_spin_rq_lock() to acquire rq lock instead of rq_lock(), there is no corresponding change to rq->clock_update_flags. In particular, we have obtained the rq lock of other CPUs, the rq->clock_update_flags of this CPU may be RQCF_UPDATED at this time, and then calling update_rq_clock() will trigger the WARN_DOUBLE_CLOCK warning. So we need to clear RQCF_UPDATED of rq->clock_update_flags to avoid the WARN_DOUBLE_CLOCK warning. For the sched_rt_period_timer() and migrate_task_rq_dl() cases we simply replace raw_spin_rq_lock()/raw_spin_rq_unlock() with rq_lock()/rq_unlock(). For the {pull,push}_{rt,dl}_task() cases, we add the double_rq_clock_clear_update() function to clear RQCF_UPDATED of rq->clock_update_flags, and call double_rq_clock_clear_update() before double_lock_balance()/double_rq_lock() returns to avoid the WARN_DOUBLE_CLOCK warning. Some call trace reports: Call Trace 1: <IRQ> sched_rt_period_timer+0x10f/0x3a0 ? enqueue_top_rt_rq+0x110/0x110 __hrtimer_run_queues+0x1a9/0x490 hrtimer_interrupt+0x10b/0x240 __sysvec_apic_timer_interrupt+0x8a/0x250 sysvec_apic_timer_interrupt+0x9a/0xd0 </IRQ> <TASK> asm_sysvec_apic_timer_interrupt+0x12/0x20 Call Trace 2: <TASK> activate_task+0x8b/0x110 push_rt_task.part.108+0x241/0x2c0 push_rt_tasks+0x15/0x30 finish_task_switch+0xaa/0x2e0 ? __switch_to+0x134/0x420 __schedule+0x343/0x8e0 ? hrtimer_start_range_ns+0x101/0x340 schedule+0x4e/0xb0 do_nanosleep+0x8e/0x160 hrtimer_nanosleep+0x89/0x120 ? hrtimer_init_sleeper+0x90/0x90 __x64_sys_nanosleep+0x96/0xd0 do_syscall_64+0x34/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xae Call Trace 3: <TASK> deactivate_task+0x93/0xe0 pull_rt_task+0x33e/0x400 balance_rt+0x7e/0x90 __schedule+0x62f/0x8e0 do_task_dead+0x3f/0x50 do_exit+0x7b8/0xbb0 do_group_exit+0x2d/0x90 get_signal+0x9df/0x9e0 ? preempt_count_add+0x56/0xa0 ? __remove_hrtimer+0x35/0x70 arch_do_signal_or_restart+0x36/0x720 ? nanosleep_copyout+0x39/0x50 ? do_nanosleep+0x131/0x160 ? audit_filter_inodes+0xf5/0x120 exit_to_user_mode_prepare+0x10f/0x1e0 syscall_exit_to_user_mode+0x17/0x30 do_syscall_64+0x40/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xae Call Trace 4: update_rq_clock+0x128/0x1a0 migrate_task_rq_dl+0xec/0x310 set_task_cpu+0x84/0x1e4 try_to_wake_up+0x1d8/0x5c0 wake_up_process+0x1c/0x30 hrtimer_wakeup+0x24/0x3c __hrtimer_run_queues+0x114/0x270 hrtimer_interrupt+0xe8/0x244 arch_timer_handler_phys+0x30/0x50 handle_percpu_devid_irq+0x88/0x140 generic_handle_domain_irq+0x40/0x60 gic_handle_irq+0x48/0xe0 call_on_irq_stack+0x2c/0x60 do_interrupt_handler+0x80/0x84 Steps to reproduce: 1. Enable CONFIG_SCHED_DEBUG when compiling the kernel 2. echo 1 > /sys/kernel/debug/clear_warn_once echo "WARN_DOUBLE_CLOCK" > /sys/kernel/debug/sched/features echo "NO_RT_PUSH_IPI" > /sys/kernel/debug/sched/features 3. Run some rt/dl tasks that periodically work and sleep, e.g. Create 2*n rt or dl (90% running) tasks via rt-app (on a system with n CPUs), and Dietmar Eggemann reports Call Trace 4 when running on PREEMPT_RT kernel. Signed-off-by: Hao Jia <jiahao.os@bytedance.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com> Link: https://lore.kernel.org/r/20220430085843.62939-2-jiahao.os@bytedance.com
2022-05-09sched: Fix build warning without CONFIG_SYSCTLYueHaibing1-29/+36
IF CONFIG_SYSCTL is n, build warn: kernel/sched/core.c:1782:12: warning: ‘sysctl_sched_uclamp_handler’ defined but not used [-Wunused-function] static int sysctl_sched_uclamp_handler(struct ctl_table *table, int write, ^~~~~~~~~~~~~~~~~~~~~~~~~~~ sysctl_sched_uclamp_handler() is used while CONFIG_SYSCTL enabled, wrap all related code with CONFIG_SYSCTL to fix this. Fixes: 3267e0156c33 ("sched: Move uclamp_util sysctls to core.c") Signed-off-by: YueHaibing <yuehaibing@huawei.com> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
2022-05-06Merge tag 'v5.18-rc5' into sched/core to pull in fixes & to resolve a conflictIngo Molnar1-5/+11
- 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 <mingo@kernel.org>
2022-05-01smp: Rename flush_smp_call_function_from_idle()Thomas Gleixner1-1/+1
This is invoked from the stopper thread too, which is definitely not idle. Rename it to flush_smp_call_function_queue() and fixup the callers. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20220413133024.305001096@linutronix.de
2022-05-01sched: Fix missing prototype warningsThomas Gleixner1-0/+3
A W=1 build emits more than a dozen missing prototype warnings related to scheduler and scheduler specific includes. Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20220413133024.249118058@linutronix.de
2022-04-06sched: Move uclamp_util sysctls to core.cZhen Ni1-11/+37
move uclamp_util sysctls to core.c and use the new register_sysctl_init() to register the sysctl interface. Signed-off-by: Zhen Ni <nizhen@uniontech.com> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
2022-04-06sched: Move rt_period/runtime sysctls to rt.cZhen Ni1-13/+0
move rt_period/runtime sysctls to rt.c and use the new register_sysctl_init() to register the sysctl interface. Signed-off-by: Zhen Ni <nizhen@uniontech.com> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
2022-04-06sched: Move schedstats sysctls to core.cZhen Ni1-1/+21
move schedstats sysctls to core.c and use the new register_sysctl_init() to register the sysctl interface. Signed-off-by: Zhen Ni <nizhen@uniontech.com> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
2022-04-05preempt/dynamic: Introduce preemption model accessorsValentin Schneider1-0/+12
CONFIG_PREEMPT{_NONE, _VOLUNTARY} designate either: o The build-time preemption model when !PREEMPT_DYNAMIC o The default boot-time preemption model when PREEMPT_DYNAMIC IOW, using those on PREEMPT_DYNAMIC kernels is meaningless - the actual model could have been set to something else by the "preempt=foo" cmdline parameter. Same problem applies to CONFIG_PREEMPTION. Introduce a set of helpers to determine the actual preemption model used by the live kernel. Suggested-by: Marco Elver <elver@google.com> Signed-off-by: Valentin Schneider <valentin.schneider@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Marco Elver <elver@google.com> Acked-by: Frederic Weisbecker <frederic@kernel.org> Link: https://lore.kernel.org/r/20211112185203.280040-3-valentin.schneider@arm.com
2022-04-05kcsan: Use preemption model accessorsValentin Schneider0-0/+0
Per PREEMPT_DYNAMIC, checking CONFIG_PREEMPT doesn't tell you the actual preemption model of the live kernel. Use the newly-introduced accessors instead. Signed-off-by: Valentin Schneider <valentin.schneider@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Marco Elver <elver@google.com> Acked-by: Frederic Weisbecker <frederic@kernel.org> Link: https://lore.kernel.org/r/20211112185203.280040-4-valentin.schneider@arm.com
2022-04-05sched: Teach the forced-newidle balancer about CPU affinity limitation.Sebastian Andrzej Siewior1-1/+1
try_steal_cookie() looks at task_struct::cpus_mask to decide if the task could be moved to `this' CPU. It ignores that the task might be in a migration disabled section while not on the CPU. In this case the task must not be moved otherwise per-CPU assumption are broken. Use is_cpu_allowed(), as suggested by Peter Zijlstra, to decide if the a task can be moved. Fixes: d2dfa17bc7de6 ("sched: Trivial forced-newidle balancer") Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/YjNK9El+3fzGmswf@linutronix.de
2022-04-05sched/core: Fix forceidle balancingPeter Zijlstra1-4/+10
Steve reported that ChromeOS encounters the forceidle balancer being ran from rt_mutex_setprio()'s balance_callback() invocation and explodes. Now, the forceidle balancer gets queued every time the idle task gets selected, set_next_task(), which is strictly too often. rt_mutex_setprio() also uses set_next_task() in the 'change' pattern: queued = task_on_rq_queued(p); /* p->on_rq == TASK_ON_RQ_QUEUED */ running = task_current(rq, p); /* rq->curr == p */ if (queued) dequeue_task(...); if (running) put_prev_task(...); /* change task properties */ if (queued) enqueue_task(...); if (running) set_next_task(...); However, rt_mutex_setprio() will explicitly not run this pattern on the idle task (since priority boosting the idle task is quite insane). Most other 'change' pattern users are pidhash based and would also not apply to idle. Also, the change pattern doesn't contain a __balance_callback() invocation and hence we could have an out-of-band balance-callback, which *should* trigger the WARN in rq_pin_lock() (which guards against this exact anti-pattern). So while none of that explains how this happens, it does indicate that having it in set_next_task() might not be the most robust option. Instead, explicitly queue the forceidle balancer from pick_next_task() when it does indeed result in forceidle selection. Having it here, ensures it can only be triggered under the __schedule() rq->lock instance, and hence must be ran from that context. This also happens to clean up the code a little, so win-win. Fixes: d2dfa17bc7de ("sched: Trivial forced-newidle balancer") Reported-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Tested-by: T.J. Alumbaugh <talumbau@chromium.org> Link: https://lkml.kernel.org/r/20220330160535.GN8939@worktop.programming.kicks-ass.net
2022-03-22Merge branch 'akpm' (patches from Andrew)Linus Torvalds1-4/+17
Merge updates from Andrew Morton: - A few misc subsystems: kthread, scripts, ntfs, ocfs2, block, and vfs - Most the MM patches which precede the patches in Willy's tree: kasan, pagecache, gup, swap, shmem, memcg, selftests, pagemap, mremap, sparsemem, vmalloc, pagealloc, memory-failure, mlock, hugetlb, userfaultfd, vmscan, compaction, mempolicy, oom-kill, migration, thp, cma, autonuma, psi, ksm, page-poison, madvise, memory-hotplug, rmap, zswap, uaccess, ioremap, highmem, cleanups, kfence, hmm, and damon. * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (227 commits) mm/damon/sysfs: remove repeat container_of() in damon_sysfs_kdamond_release() Docs/ABI/testing: add DAMON sysfs interface ABI document Docs/admin-guide/mm/damon/usage: document DAMON sysfs interface selftests/damon: add a test for DAMON sysfs interface mm/damon/sysfs: support DAMOS stats mm/damon/sysfs: support DAMOS watermarks mm/damon/sysfs: support schemes prioritization mm/damon/sysfs: support DAMOS quotas mm/damon/sysfs: support DAMON-based Operation Schemes mm/damon/sysfs: support the physical address space monitoring mm/damon/sysfs: link DAMON for virtual address spaces monitoring mm/damon: implement a minimal stub for sysfs-based DAMON interface mm/damon/core: add number of each enum type values mm/damon/core: allow non-exclusive DAMON start/stop Docs/damon: update outdated term 'regions update interval' Docs/vm/damon/design: update DAMON-Idle Page Tracking interference handling Docs/vm/damon: call low level monitoring primitives the operations mm/damon: remove unnecessary CONFIG_DAMON option mm/damon/paddr,vaddr: remove damon_{p,v}a_{target_valid,set_operations}() mm/damon/dbgfs-test: fix is_target_id() change ...
2022-03-22NUMA balancing: optimize page placement for memory tiering systemHuang Ying1-4/+17
With the advent of various new memory types, some machines will have multiple types of memory, e.g. DRAM and PMEM (persistent memory). The memory subsystem of these machines can be called memory tiering system, because the performance of the different types of memory are usually different. In such system, because of the memory accessing pattern changing etc, some pages in the slow memory may become hot globally. So in this patch, the NUMA balancing mechanism is enhanced to optimize the page placement among the different memory types according to hot/cold dynamically. In a typical memory tiering system, there are CPUs, fast memory and slow memory in each physical NUMA node. The CPUs and the fast memory will be put in one logical node (called fast memory node), while the slow memory will be put in another (faked) logical node (called slow memory node). That is, the fast memory is regarded as local while the slow memory is regarded as remote. So it's possible for the recently accessed pages in the slow memory node to be promoted to the fast memory node via the existing NUMA balancing mechanism. The original NUMA balancing mechanism will stop to migrate pages if the free memory of the target node becomes below the high watermark. This is a reasonable policy if there's only one memory type. But this makes the original NUMA balancing mechanism almost do not work to optimize page placement among different memory types. Details are as follows. It's the common cases that the working-set size of the workload is larger than the size of the fast memory nodes. Otherwise, it's unnecessary to use the slow memory at all. So, there are almost always no enough free pages in the fast memory nodes, so that the globally hot pages in the slow memory node cannot be promoted to the fast memory node. To solve the issue, we have 2 choices as follows, a. Ignore the free pages watermark checking when promoting hot pages from the slow memory node to the fast memory node. This will create some memory pressure in the fast memory node, thus trigger the memory reclaiming. So that, the cold pages in the fast memory node will be demoted to the slow memory node. b. Define a new watermark called wmark_promo which is higher than wmark_high, and have kswapd reclaiming pages until free pages reach such watermark. The scenario is as follows: when we want to promote hot-pages from a slow memory to a fast memory, but fast memory's free pages would go lower than high watermark with such promotion, we wake up kswapd with wmark_promo watermark in order to demote cold pages and free us up some space. So, next time we want to promote hot-pages we might have a chance of doing so. The choice "a" may create high memory pressure in the fast memory node. If the memory pressure of the workload is high, the memory pressure may become so high that the memory allocation latency of the workload is influenced, e.g. the direct reclaiming may be triggered. The choice "b" works much better at this aspect. If the memory pressure of the workload is high, the hot pages promotion will stop earlier because its allocation watermark is higher than that of the normal memory allocation. So in this patch, choice "b" is implemented. A new zone watermark (WMARK_PROMO) is added. Which is larger than the high watermark and can be controlled via watermark_scale_factor. In addition to the original page placement optimization among sockets, the NUMA balancing mechanism is extended to be used to optimize page placement according to hot/cold among different memory types. So the sysctl user space interface (numa_balancing) is extended in a backward compatible way as follow, so that the users can enable/disable these functionality individually. The sysctl is converted from a Boolean value to a bits field. The definition of the flags is, - 0: NUMA_BALANCING_DISABLED - 1: NUMA_BALANCING_NORMAL - 2: NUMA_BALANCING_MEMORY_TIERING We have tested the patch with the pmbench memory accessing benchmark with the 80:20 read/write ratio and the Gauss access address distribution on a 2 socket Intel server with Optane DC Persistent Memory Model. The test results shows that the pmbench score can improve up to 95.9%. Thanks Andrew Morton to help fix the document format error. Link: https://lkml.kernel.org/r/20220221084529.1052339-3-ying.huang@intel.com Signed-off-by: "Huang, Ying" <ying.huang@intel.com> Tested-by: Baolin Wang <baolin.wang@linux.alibaba.com> Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Oscar Salvador <osalvador@suse.de> Reviewed-by: Yang Shi <shy828301@gmail.com> 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: Zi Yan <ziy@nvidia.com> Cc: Wei Xu <weixugc@google.com> Cc: Shakeel Butt <shakeelb@google.com> Cc: zhongjiang-ali <zhongjiang-ali@linux.alibaba.com> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Feng Tang <feng.tang@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2022-03-22Merge tag 'sched-core-2022-03-22' of ↵Linus Torvalds1-164/+302
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull scheduler updates from Ingo Molnar: - Cleanups for SCHED_DEADLINE - Tracing updates/fixes - CPU Accounting fixes - First wave of changes to optimize the overhead of the scheduler build, from the fast-headers tree - including placeholder *_api.h headers for later header split-ups. - Preempt-dynamic using static_branch() for ARM64 - Isolation housekeeping mask rework; preperatory for further changes - NUMA-balancing: deal with CPU-less nodes - NUMA-balancing: tune systems that have multiple LLC cache domains per node (eg. AMD) - Updates to RSEQ UAPI in preparation for glibc usage - Lots of RSEQ/selftests, for same - Add Suren as PSI co-maintainer * tag 'sched-core-2022-03-22' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (81 commits) sched/headers: ARM needs asm/paravirt_api_clock.h too sched/numa: Fix boot crash on arm64 systems headers/prep: Fix header to build standalone: <linux/psi.h> sched/headers: Only include <linux/entry-common.h> when CONFIG_GENERIC_ENTRY=y cgroup: Fix suspicious rcu_dereference_check() usage warning sched/preempt: Tell about PREEMPT_DYNAMIC on kernel headers sched/topology: Remove redundant variable and fix incorrect type in build_sched_domains sched/deadline,rt: Remove unused parameter from pick_next_[rt|dl]_entity() sched/deadline,rt: Remove unused functions for !CONFIG_SMP sched/deadline: Use __node_2_[pdl|dle]() and rb_first_cached() consistently sched/deadline: Merge dl_task_can_attach() and dl_cpu_busy() sched/deadline: Move bandwidth mgmt and reclaim functions into sched class source file sched/deadline: Remove unused def_dl_bandwidth sched/tracing: Report TASK_RTLOCK_WAIT tasks as TASK_UNINTERRUPTIBLE sched/tracing: Don't re-read p->state when emitting sched_switch event sched/rt: Plug rt_mutex_setprio() vs push_rt_task() race sched/cpuacct: Remove redundant RCU read lock sched/cpuacct: Optimize away RCU read lock sched/cpuacct: Fix charge percpu cpuusage sched/headers: Reorganize, clean up and optimize kernel/sched/sched.h dependencies ...
2022-03-21Merge tag 'for-5.18/block-2022-03-18' of git://git.kernel.dk/linux-blockLinus Torvalds1-5/+2
Pull block updates from Jens Axboe: - BFQ cleanups and fixes (Yu, Zhang, Yahu, Paolo) - blk-rq-qos completion fix (Tejun) - blk-cgroup merge fix (Tejun) - Add offline error return value to distinguish it from an IO error on the device (Song) - IO stats fixes (Zhang, Christoph) - blkcg refcount fixes (Ming, Yu) - Fix for indefinite dispatch loop softlockup (Shin'ichiro) - blk-mq hardware queue management improvements (Ming) - sbitmap dead code removal (Ming, John) - Plugging merge improvements (me) - Show blk-crypto capabilities in sysfs (Eric) - Multiple delayed queue run improvement (David) - Block throttling fixes (Ming) - Start deprecating auto module loading based on dev_t (Christoph) - bio allocation improvements (Christoph, Chaitanya) - Get rid of bio_devname (Christoph) - bio clone improvements (Christoph) - Block plugging improvements (Christoph) - Get rid of genhd.h header (Christoph) - Ensure drivers use appropriate flush helpers (Christoph) - Refcounting improvements (Christoph) - Queue initialization and teardown improvements (Ming, Christoph) - Misc fixes/improvements (Barry, Chaitanya, Colin, Dan, Jiapeng, Lukas, Nian, Yang, Eric, Chengming) * tag 'for-5.18/block-2022-03-18' of git://git.kernel.dk/linux-block: (127 commits) block: cancel all throttled bios in del_gendisk() block: let blkcg_gq grab request queue's refcnt block: avoid use-after-free on throttle data block: limit request dispatch loop duration block/bfq-iosched: Fix spelling mistake "tenative" -> "tentative" sr: simplify the local variable initialization in sr_block_open() block: don't merge across cgroup boundaries if blkcg is enabled block: fix rq-qos breakage from skipping rq_qos_done_bio() block: flush plug based on hardware and software queue order block: ensure plug merging checks the correct queue at least once block: move rq_qos_exit() into disk_release() block: do more work in elevator_exit block: move blk_exit_queue into disk_release block: move q_usage_counter release into blk_queue_release block: don't remove hctx debugfs dir from blk_mq_exit_queue block: move blkcg initialization/destroy into disk allocation/release handler sr: implement ->free_disk to simplify refcounting sd: implement ->free_disk to simplify refcounting sd: delay calling free_opal_dev sd: call sd_zbc_release_disk before releasing the scsi_device reference ...
2022-03-15sched/headers: Only include <linux/entry-common.h> when CONFIG_GENERIC_ENTRY=yIngo Molnar1-1/+3
This header is not (yet) standalone. Signed-off-by: Ingo Molnar <mingo@kernel.org>
2022-03-15Merge branch 'sched/fast-headers' into sched/coreIngo Molnar1-10/+71
Merge the scheduler build speedup of the fast-headers tree. Cumulative scheduler (kernel/sched/) build time speedup on a Linux distribution's config, which enables all scheduler features, compared to the vanilla kernel: _____________________________________________________________________________ | | Vanilla kernel (v5.13-rc7): |_____________________________________________________________________________ | | Performance counter stats for 'make -j96 kernel/sched/' (3 runs): | | 126,975,564,374 instructions # 1.45 insn per cycle ( +- 0.00% ) | 87,637,847,671 cycles # 3.959 GHz ( +- 0.30% ) | 22,136.96 msec cpu-clock # 7.499 CPUs utilized ( +- 0.29% ) | | 2.9520 +- 0.0169 seconds time elapsed ( +- 0.57% ) |_____________________________________________________________________________ | | Patched kernel: |_____________________________________________________________________________ | | Performance counter stats for 'make -j96 kernel/sched/' (3 runs): | | 50,420,496,914 instructions # 1.47 insn per cycle ( +- 0.00% ) | 34,234,322,038 cycles # 3.946 GHz ( +- 0.31% ) | 8,675.81 msec cpu-clock # 3.053 CPUs utilized ( +- 0.45% ) | | 2.8420 +- 0.0181 seconds time elapsed ( +- 0.64% ) |_____________________________________________________________________________ Summary: - CPU time used to build the scheduler dropped by -60.9%, a reduction from 22.1 clock-seconds to 8.7 clock-seconds. - Wall-clock time to build the scheduler dropped by -3.9%, a reduction from 2.95 seconds to 2.84 seconds. Signed-off-by: Ingo Molnar <mingo@kernel.org>
2022-03-08sched/deadline: Merge dl_task_can_attach() and dl_cpu_busy()Dietmar Eggemann1-4/+9
Both functions are doing almost the same, that is checking if admission control is still respected. With exclusive cpusets, dl_task_can_attach() checks if the destination cpuset (i.e. its root domain) has enough CPU capacity to accommodate the task. dl_cpu_busy() checks if there is enough CPU capacity in the cpuset in case the CPU is hot-plugged out. dl_task_can_attach() is used to check if a task can be admitted while dl_cpu_busy() is used to check if a CPU can be hotplugged out. Make dl_cpu_busy() able to deal with a task and use it instead of dl_task_can_attach() in task_can_attach(). Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Juri Lelli <juri.lelli@redhat.com> Link: https://lore.kernel.org/r/20220302183433.333029-4-dietmar.eggemann@arm.com
2022-03-08sched/deadline: Remove unused def_dl_bandwidthDietmar Eggemann1-1/+0
Since commit 1724813d9f2c ("sched/deadline: Remove the sysctl_sched_dl knobs") the default deadline bandwidth control structure has no purpose. Remove it. Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Juri Lelli <juri.lelli@redhat.com> Link: https://lore.kernel.org/r/20220302183433.333029-2-dietmar.eggemann@arm.com
2022-03-01sched/tracing: Don't re-read p->state when emitting sched_switch eventValentin Schneider1-2/+2
As of commit c6e7bd7afaeb ("sched/core: Optimize ttwu() spinning on p->on_cpu") the following sequence becomes possible: p->__state = TASK_INTERRUPTIBLE; __schedule() deactivate_task(p); ttwu() READ !p->on_rq p->__state=TASK_WAKING trace_sched_switch() __trace_sched_switch_state() task_state_index() return 0; TASK_WAKING isn't in TASK_REPORT, so the task appears as TASK_RUNNING in the trace event. Prevent this by pushing the value read from __schedule() down the trace event. Reported-by: Abhijeet Dharmapurikar <adharmap@quicinc.com> Signed-off-by: Valentin Schneider <valentin.schneider@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org> Link: https://lore.kernel.org/r/20220120162520.570782-2-valentin.schneider@arm.com
2022-02-23sched/headers: Reorganize, clean up and optimize kernel/sched/core.c ↵Ingo Molnar1-11/+70
dependencies Use all generic headers from kernel/sched/sched.h that are required for it to build. Sort the sections alphabetically. Signed-off-by: Ingo Molnar <mingo@kernel.org> Reviewed-by: Peter Zijlstra <peterz@infradead.org>
2022-02-23sched/headers: Standardize kernel/sched/sched.h header dependenciesIngo Molnar1-0/+2
kernel/sched/sched.h is a weird mix of ad-hoc headers included in the middle of the header. Two of them rely on being included in the middle of kernel/sched/sched.h, due to definitions they require: - "stat.h" needs the rq definitions. - "autogroup.h" needs the task_group definition. Move the inclusion of these two files out of kernel/sched/sched.h, and include them in all files that require them. Move of the rest of the header dependencies to the top of the kernel/sched/sched.h file. Signed-off-by: Ingo Molnar <mingo@kernel.org> Reviewed-by: Peter Zijlstra <peterz@infradead.org>
2022-02-21Merge tag 'v5.17-rc5' into sched/core, to resolve conflictsIngo Molnar1-18/+20
New conflicts in sched/core due to the following upstream fixes: 44585f7bc0cb ("psi: fix "defined but not used" warnings when CONFIG_PROC_FS=n") a06247c6804f ("psi: Fix uaf issue when psi trigger is destroyed while being polled") Conflicts: include/linux/psi_types.h kernel/sched/psi.c Signed-off-by: Ingo Molnar <mingo@kernel.org>
2022-02-19sched/preempt: Add PREEMPT_DYNAMIC using static keysMark Rutland1-2/+52
Where an architecture selects HAVE_STATIC_CALL but not HAVE_STATIC_CALL_INLINE, each static call has an out-of-line trampoline which will either branch to a callee or return to the caller. On such architectures, a number of constraints can conspire to make those trampolines more complicated and potentially less useful than we'd like. For example: * Hardware and software control flow integrity schemes can require the addition of "landing pad" instructions (e.g. `BTI` for arm64), which will also be present at the "real" callee. * Limited branch ranges can require that trampolines generate or load an address into a register and perform an indirect branch (or at least have a slow path that does so). This loses some of the benefits of having a direct branch. * Interaction with SW CFI schemes can be complicated and fragile, e.g. requiring that we can recognise idiomatic codegen and remove indirections understand, at least until clang proves more helpful mechanisms for dealing with this. For PREEMPT_DYNAMIC, we don't need the full power of static calls, as we really only need to enable/disable specific preemption functions. We can achieve the same effect without a number of the pain points above by using static keys to fold early returns into the preemption functions themselves rather than in an out-of-line trampoline, effectively inlining the trampoline into the start of the function. For arm64, this results in good code generation. For example, the dynamic_cond_resched() wrapper looks as follows when enabled. When disabled, the first `B` is replaced with a `NOP`, resulting in an early return. | <dynamic_cond_resched>: | bti c | b <dynamic_cond_resched+0x10> // or `nop` | mov w0, #0x0 | ret | mrs x0, sp_el0 | ldr x0, [x0, #8] | cbnz x0, <dynamic_cond_resched+0x8> | paciasp | stp x29, x30, [sp, #-16]! | mov x29, sp | bl <preempt_schedule_common> | mov w0, #0x1 | ldp x29, x30, [sp], #16 | autiasp | ret ... compared to the regular form of the function: | <__cond_resched>: | bti c | mrs x0, sp_el0 | ldr x1, [x0, #8] | cbz x1, <__cond_resched+0x18> | mov w0, #0x0 | ret | paciasp | stp x29, x30, [sp, #-16]! | mov x29, sp | bl <preempt_schedule_common> | mov w0, #0x1 | ldp x29, x30, [sp], #16 | autiasp | ret Any architecture which implements static keys should be able to use this to implement PREEMPT_DYNAMIC with similar cost to non-inlined static calls. Since this is likely to have greater overhead than (inlined) static calls, PREEMPT_DYNAMIC is only defaulted to enabled when HAVE_PREEMPT_DYNAMIC_CALL is selected. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Ard Biesheuvel <ardb@kernel.org> Acked-by: Frederic Weisbecker <frederic@kernel.org> Link: https://lore.kernel.org/r/20220214165216.2231574-6-mark.rutland@arm.com
2022-02-19sched/preempt: Decouple HAVE_PREEMPT_DYNAMIC from GENERIC_ENTRYMark Rutland1-0/+2
Now that the enabled/disabled states for the preemption functions are declared alongside their definitions, the core PREEMPT_DYNAMIC logic is no longer tied to GENERIC_ENTRY, and can safely be selected so long as an architecture provides enabled/disabled states for irqentry_exit_cond_resched(). Make it possible to select HAVE_PREEMPT_DYNAMIC without GENERIC_ENTRY. For existing users of HAVE_PREEMPT_DYNAMIC there should be no functional change as a result of this patch. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Ard Biesheuvel <ardb@kernel.org> Acked-by: Frederic Weisbecker <frederic@kernel.org> Link: https://lore.kernel.org/r/20220214165216.2231574-5-mark.rutland@arm.com
2022-02-19sched/preempt: Refactor sched_dynamic_update()Mark Rutland1-22/+37
Currently sched_dynamic_update needs to open-code the enabled/disabled function names for each preemption model it supports, when in practice this is a boolean enabled/disabled state for each function. Make this clearer and avoid repetition by defining the enabled/disabled states at the function definition, and using helper macros to perform the static_call_update(). Where x86 currently overrides the enabled function, it is made to provide both the enabled and disabled states for consistency, with defaults provided by the core code otherwise. In subsequent patches this will allow us to support PREEMPT_DYNAMIC without static calls. There should be no functional change as a result of this patch. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Ard Biesheuvel <ardb@kernel.org> Acked-by: Frederic Weisbecker <frederic@kernel.org> Link: https://lore.kernel.org/r/20220214165216.2231574-3-mark.rutland@arm.com
2022-02-19sched/preempt: Move PREEMPT_DYNAMIC logic laterMark Rutland1-136/+136
The PREEMPT_DYNAMIC logic in kernel/sched/core.c patches static calls for a bunch of preemption functions. While most are defined prior to this, the definition of cond_resched() is later in the file, and so we only have its declarations from include/linux/sched.h. In subsequent patches we'd like to define some macros alongside the definition of each of the preemption functions, which we can use within sched_dynamic_update(). For this to be possible, the PREEMPT_DYNAMIC logic needs to be placed after the various preemption functions. As a preparatory step, this patch moves the PREEMPT_DYNAMIC logic after the various preemption functions, with no other changes -- this is purely a move. There should be no functional change as a result of this patch. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Ard Biesheuvel <ardb@kernel.org> Acked-by: Frederic Weisbecker <frederic@kernel.org> Link: https://lore.kernel.org/r/20220214165216.2231574-2-mark.rutland@arm.com
2022-02-19sched: Fix yet more sched_fork() racesPeter Zijlstra1-13/+21
Where commit 4ef0c5c6b5ba ("kernel/sched: Fix sched_fork() access an invalid sched_task_group") fixed a fork race vs cgroup, it opened up a race vs syscalls by not placing the task on the runqueue before it gets exposed through the pidhash. Commit 13765de8148f ("sched/fair: Fix fault in reweight_entity") is trying to fix a single instance of this, instead fix the whole class of issues, effectively reverting this commit. Fixes: 4ef0c5c6b5ba ("kernel/sched: Fix sched_fork() access an invalid sched_task_group") Reported-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Tested-by: Tadeusz Struk <tadeusz.struk@linaro.org> Tested-by: Zhang Qiao <zhangqiao22@huawei.com> Tested-by: Dietmar Eggemann <dietmar.eggemann@arm.com> Link: https://lkml.kernel.org/r/YgoeCbwj5mbCR0qA@hirez.programming.kicks-ass.net
2022-02-16sched/isolation: Use single feature type while referring to housekeeping cpumaskFrederic Weisbecker1-6/+6
Refer to housekeeping APIs using single feature types instead of flags. This prevents from passing multiple isolation features at once to housekeeping interfaces, which soon won't be possible anymore as each isolation features will have their own cpumask. Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Juri Lelli <juri.lelli@redhat.com> Reviewed-by: Phil Auld <pauld@redhat.com> Link: https://lore.kernel.org/r/20220207155910.527133-5-frederic@kernel.org
2022-02-16sched/numa: Fix NUMA topology for systems with CPU-less nodesHuang Ying1-1/+4
The NUMA topology parameters (sched_numa_topology_type, sched_domains_numa_levels, and sched_max_numa_distance, etc.) identified by scheduler may be wrong for systems with CPU-less nodes. For example, the ACPI SLIT of a system with CPU-less persistent memory (Intel Optane DCPMM) nodes is as follows, [000h 0000 4] Signature : "SLIT" [System Locality Information Table] [004h 0004 4] Table Length : 0000042C [008h 0008 1] Revision : 01 [009h 0009 1] Checksum : 59 [00Ah 0010 6] Oem ID : "XXXX" [010h 0016 8] Oem Table ID : "XXXXXXX" [018h 0024 4] Oem Revision : 00000001 [01Ch 0028 4] Asl Compiler ID : "INTL" [020h 0032 4] Asl Compiler Revision : 20091013 [024h 0036 8] Localities : 0000000000000004 [02Ch 0044 4] Locality 0 : 0A 15 11 1C [030h 0048 4] Locality 1 : 15 0A 1C 11 [034h 0052 4] Locality 2 : 11 1C 0A 1C [038h 0056 4] Locality 3 : 1C 11 1C 0A While the `numactl -H` output is as follows, available: 4 nodes (0-3) node 0 cpus: 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 node 0 size: 64136 MB node 0 free: 5981 MB node 1 cpus: 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 node 1 size: 64466 MB node 1 free: 10415 MB node 2 cpus: node 2 size: 253952 MB node 2 free: 253920 MB node 3 cpus: node 3 size: 253952 MB node 3 free: 253951 MB node distances: node 0 1 2 3 0: 10 21 17 28 1: 21 10 28 17 2: 17 28 10 28 3: 28 17 28 10 In this system, there are only 2 sockets. In each memory controller, both DRAM and PMEM DIMMs are installed. Although the physical NUMA topology is simple, the logical NUMA topology becomes a little complex. Because both the distance(0, 1) and distance (1, 3) are less than the distance (0, 3), it appears that node 1 sits between node 0 and node 3. And the whole system appears to be a glueless mesh NUMA topology type. But it's definitely not, there is even no CPU in node 3. This isn't a practical problem now yet. Because the PMEM nodes (node 2 and node 3 in example system) are offlined by default during system boot. So init_numa_topology_type() called during system boot will ignore them and set sched_numa_topology_type to NUMA_DIRECT. And init_numa_topology_type() is only called at runtime when a CPU of a never-onlined-before node gets plugged in. And there's no CPU in the PMEM nodes. But it appears better to fix this to make the code more robust. To test the potential problem. We have used a debug patch to call init_numa_topology_type() when the PMEM node is onlined (in __set_migration_target_nodes()). With that, the NUMA parameters identified by scheduler is as follows, sched_numa_topology_type: NUMA_GLUELESS_MESH sched_domains_numa_levels: 4 sched_max_numa_distance: 28 To fix the issue, the CPU-less nodes are ignored when the NUMA topology parameters are identified. Because a node may become CPU-less or not at run time because of CPU hotplug, the NUMA topology parameters need to be re-initialized at runtime for CPU hotplug too. With the patch, the NUMA parameters identified for the example system above is as follows, sched_numa_topology_type: NUMA_DIRECT sched_domains_numa_levels: 2 sched_max_numa_distance: 21 Suggested-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: "Huang, Ying" <ying.huang@intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20220214121553.582248-1-ying.huang@intel.com
2022-02-16sched: replace cpumask_weight with cpumask_empty where appropriateYury Norov1-1/+1
In some places, kernel/sched code calls cpumask_weight() to check if any bit of a given cpumask is set. We can do it more efficiently with cpumask_empty() because cpumask_empty() stops traversing the cpumask as soon as it finds first set bit, while cpumask_weight() counts all bits unconditionally. Signed-off-by: Yury Norov <yury.norov@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20220210224933.379149-23-yury.norov@gmail.com
2022-02-06sched/fair: Fix fault in reweight_entityTadeusz Struk1-5/+6
Syzbot found a GPF in reweight_entity. This has been bisected to commit 4ef0c5c6b5ba ("kernel/sched: Fix sched_fork() access an invalid sched_task_group") There is a race between sched_post_fork() and setpriority(PRIO_PGRP) within a thread group that causes a null-ptr-deref in reweight_entity() in CFS. The scenario is that the main process spawns number of new threads, which then call setpriority(PRIO_PGRP, 0, -20), wait, and exit. For each of the new threads the copy_process() gets invoked, which adds the new task_struct and calls sched_post_fork() for it. In the above scenario there is a possibility that setpriority(PRIO_PGRP) and set_one_prio() will be called for a thread in the group that is just being created by copy_process(), and for which the sched_post_fork() has not been executed yet. This will trigger a null pointer dereference in reweight_entity(), as it will try to access the run queue pointer, which hasn't been set. Before the mentioned change the cfs_rq pointer for the task has been set in sched_fork(), which is called much earlier in copy_process(), before the new task is added to the thread_group. Now it is done in the sched_post_fork(), which is called after that. To fix the issue the remove the update_load param from the update_load param() function and call reweight_task() only if the task flag doesn't have the TASK_NEW flag set. Fixes: 4ef0c5c6b5ba ("kernel/sched: Fix sched_fork() access an invalid sched_task_group") Reported-by: syzbot+af7a719bc92395ee41b3@syzkaller.appspotmail.com Signed-off-by: Tadeusz Struk <tadeusz.struk@linaro.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com> Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20220203161846.1160750-1-tadeusz.struk@linaro.org
2022-02-02block: check that there is a plug in blk_flush_plugChristoph Hellwig1-5/+2
Rename blk_flush_plug to __blk_flush_plug and add a wrapper that includes the NULL check instead of open coding that check everywhere. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com> Link: https://lore.kernel.org/r/20220127070549.1377856-2-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-02-02block: remove blk_needs_flush_plugChristoph Hellwig1-1/+1
blk_needs_flush_plug fails to account for the cb_list, which needs flushing as well. Remove it and just check if there is a plug instead of poking into the internals of the plug structure. Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20220127070549.1377856-1-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-01-27sched/core: Export pelt_thermal_tpQais Yousef1-0/+1
We can't use this tracepoint in modules without having the symbol exported first, fix that. Fixes: 765047932f15 ("sched/pelt: Add support to track thermal pressure") Signed-off-by: Qais Yousef <qais.yousef@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20211028115005.873539-1-qais.yousef@arm.com
2022-01-23Merge tag 'sched_urgent_for_v5.17_rc2' of ↵Linus Torvalds1-11/+4
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull scheduler fixes from Borislav Petkov: "A bunch of fixes: forced idle time accounting, utilization values propagation in the sched hierarchies and other minor cleanups and improvements" * tag 'sched_urgent_for_v5.17_rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: kernel/sched: Remove dl_boosted flag comment sched: Avoid double preemption in __cond_resched_*lock*() sched/fair: Fix all kernel-doc warnings sched/core: Accounting forceidle time for all tasks except idle task sched/pelt: Relax the sync of load_sum with load_avg sched/pelt: Relax the sync of runnable_sum with runnable_avg sched/pelt: Continue to relax the sync of util_sum with util_avg sched/pelt: Relax the sync of util_sum with util_avg psi: Fix uaf issue when psi trigger is destroyed while being polled
2022-01-18sched: Avoid double preemption in __cond_resched_*lock*()Peter Zijlstra1-9/+3
For PREEMPT/DYNAMIC_PREEMPT the *_unlock() will already trigger a preemption, no point in then calling preempt_schedule_common() *again*. Use _cond_resched() instead, since this is a NOP for the preemptible configs while it provide a preemption point for the others. Reported-by: xuhaifeng <xuhaifeng@oppo.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/YcGnvDEYBwOiV0cR@hirez.programming.kicks-ass.net
2022-01-18sched/core: Accounting forceidle time for all tasks except idle taskCruz Zhao1-2/+1
There are two types of forced idle time: forced idle time from cookie'd task and forced idle time form uncookie'd task. The forced idle time from uncookie'd task is actually caused by the cookie'd task in runqueue indirectly, and it's more accurate to measure the capacity loss with the sum of both. Assuming cpu x and cpu y are a pair of SMT siblings, consider the following scenarios: 1.There's a cookie'd task running on cpu x, and there're 4 uncookie'd tasks running on cpu y. For cpu x, there will be 80% forced idle time (from uncookie'd task); for cpu y, there will be 20% forced idle time (from cookie'd task). 2.There's a uncookie'd task running on cpu x, and there're 4 cookie'd tasks running on cpu y. For cpu x, there will be 80% forced idle time (from cookie'd task); for cpu y, there will be 20% forced idle time (from uncookie'd task). The scenario1 can recurrent by stress-ng(scenario2 can recurrent similary): (cookie'd)taskset -c x stress-ng -c 1 -l 100 (uncookie'd)taskset -c y stress-ng -c 4 -l 100 In the above two scenarios, the total capacity loss is 1 cpu, but in scenario1, the cookie'd forced idle time tells us 20% cpu capacity loss, in scenario2, the cookie'd forced idle time tells us 80% cpu capacity loss, which are not accurate. It'll be more accurate to measure with cookie'd forced idle time and uncookie'd forced idle time. Signed-off-by: Cruz Zhao <CruzZhao@linux.alibaba.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Josh Don <joshdon@google.com> Link: https://lore.kernel.org/r/1641894961-9241-2-git-send-email-CruzZhao@linux.alibaba.com
2022-01-17Merge branch 'signal-for-v5.17' of ↵Linus Torvalds1-8/+8
git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace Pull signal/exit/ptrace updates from Eric Biederman: "This set of changes deletes some dead code, makes a lot of cleanups which hopefully make the code easier to follow, and fixes bugs found along the way. The end-game which I have not yet reached yet is for fatal signals that generate coredumps to be short-circuit deliverable from complete_signal, for force_siginfo_to_task not to require changing userspace configured signal delivery state, and for the ptrace stops to always happen in locations where we can guarantee on all architectures that the all of the registers are saved and available on the stack. Removal of profile_task_ext, profile_munmap, and profile_handoff_task are the big successes for dead code removal this round. A bunch of small bug fixes are included, as most of the issues reported were small enough that they would not affect bisection so I simply added the fixes and did not fold the fixes into the changes they were fixing. There was a bug that broke coredumps piped to systemd-coredump. I dropped the change that caused that bug and replaced it entirely with something much more restrained. Unfortunately that required some rebasing. Some successes after this set of changes: There are few enough calls to do_exit to audit in a reasonable amount of time. The lifetime of struct kthread now matches the lifetime of struct task, and the pointer to struct kthread is no longer stored in set_child_tid. The flag SIGNAL_GROUP_COREDUMP is removed. The field group_exit_task is removed. Issues where task->exit_code was examined with signal->group_exit_code should been examined were fixed. There are several loosely related changes included because I am cleaning up and if I don't include them they will probably get lost. The original postings of these changes can be found at: https://lkml.kernel.org/r/87a6ha4zsd.fsf@email.froward.int.ebiederm.org https://lkml.kernel.org/r/87bl1kunjj.fsf@email.froward.int.ebiederm.org https://lkml.kernel.org/r/87r19opkx1.fsf_-_@email.froward.int.ebiederm.org I trimmed back the last set of changes to only the obviously correct once. Simply because there was less time for review than I had hoped" * 'signal-for-v5.17' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (44 commits) ptrace/m68k: Stop open coding ptrace_report_syscall ptrace: Remove unused regs argument from ptrace_report_syscall ptrace: Remove second setting of PT_SEIZED in ptrace_attach taskstats: Cleanup the use of task->exit_code exit: Use the correct exit_code in /proc/<pid>/stat exit: Fix the exit_code for wait_task_zombie exit: Coredumps reach do_group_exit exit: Remove profile_handoff_task exit: Remove profile_task_exit & profile_munmap signal: clean up kernel-doc comments signal: Remove the helper signal_group_exit signal: Rename group_exit_task group_exec_task coredump: Stop setting signal->group_exit_task signal: Remove SIGNAL_GROUP_COREDUMP signal: During coredumps set SIGNAL_GROUP_EXIT in zap_process signal: Make coredump handling explicit in complete_signal signal: Have prepare_signal detect coredumps using signal->core_state signal: Have the oom killer detect coredumps using signal->core_state exit: Move force_uaccess back into do_exit exit: Guarantee make_task_dead leaks the tsk when calling do_task_exit ...
2022-01-11Merge tag 'locking_core_for_v5.17_rc1' of ↵Linus Torvalds1-0/+3
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull locking updates from Borislav Petkov: "Lots of cleanups and preparation. Highlights: - futex: Cleanup and remove runtime futex_cmpxchg detection - rtmutex: Some fixes for the PREEMPT_RT locking infrastructure - kcsan: Share owner_on_cpu() between mutex,rtmutex and rwsem and annotate the racy owner->on_cpu access *once*. - atomic64: Dead-Code-Elemination" [ Description above by Peter Zijlstra ] * tag 'locking_core_for_v5.17_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: locking/atomic: atomic64: Remove unusable atomic ops futex: Fix additional regressions locking: Allow to include asm/spinlock_types.h from linux/spinlock_types_raw.h x86/mm: Include spinlock_t definition in pgtable. locking: Mark racy reads of owner->on_cpu locking: Make owner_on_cpu() into <linux/sched.h> lockdep/selftests: Adapt ww-tests for PREEMPT_RT lockdep/selftests: Skip the softirq related tests on PREEMPT_RT lockdep/selftests: Unbalanced migrate_disable() & rcu_read_lock(). lockdep/selftests: Avoid using local_lock_{acquire|release}(). lockdep: Remove softirq accounting on PREEMPT_RT. locking/rtmutex: Add rt_mutex_lock_nest_lock() and rt_mutex_lock_killable(). locking/rtmutex: Squash self-deadlock check for ww_rt_mutex. locking: Remove rt_rwlock_is_contended(). sched: Trigger warning if ->migration_disabled counter underflows. futex: Fix sparc32/m68k/nds32 build regression futex: Remove futex_cmpxchg detection futex: Ensure futex_atomic_cmpxchg_inatomic() is present kernel/locking: Use a pointer in ww_mutex_trylock().
2022-01-11Merge tag 'sched_core_for_v5.17_rc1' of ↵Linus Torvalds1-21/+63
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull scheduler updates from Borislav Petkov: "Mostly minor things this time; some highlights: - core-sched: Add 'Forced Idle' accounting; this allows to track how much CPU time is 'lost' due to core scheduling constraints. - psi: Fix for MEM_FULL; a task running reclaim would be counted as a runnable task and prevent MEM_FULL from being reported. - cpuacct: Long standing fixes for some cgroup accounting issues. - rt: Bandwidth timer could, under unusual circumstances, be failed to armed, leading to indefinite throttling." [ Description above by Peter Zijlstra ] * tag 'sched_core_for_v5.17_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: sched/fair: Replace CFS internal cpu_util() with cpu_util_cfs() sched/fair: Cleanup task_util and capacity type sched/rt: Try to restart rt period timer when rt runtime exceeded sched/fair: Document the slow path and fast path in select_task_rq_fair sched/fair: Fix per-CPU kthread and wakee stacking for asym CPU capacity sched/fair: Fix detection of per-CPU kthreads waking a task sched/cpuacct: Make user/system times in cpuacct.stat more precise sched/cpuacct: Fix user/system in shown cpuacct.usage* cpuacct: Convert BUG_ON() to WARN_ON_ONCE() cputime, cpuacct: Include guest time in user time in cpuacct.stat psi: Fix PSI_MEM_FULL state when tasks are in memstall and doing reclaim sched/core: Forced idle accounting psi: Add a missing SPDX license header psi: Remove repeated verbose comment
2022-01-10Merge tag 'core_entry_for_v5.17_rc1' of ↵Linus Torvalds1-1/+1
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull thread_info flag accessor helper updates from Borislav Petkov: "Add a set of thread_info.flags accessors which snapshot it before accesing it in order to prevent any potential data races, and convert all users to those new accessors" * tag 'core_entry_for_v5.17_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: powerpc: Snapshot thread flags powerpc: Avoid discarding flags in system_call_exception() openrisc: Snapshot thread flags microblaze: Snapshot thread flags arm64: Snapshot thread flags ARM: Snapshot thread flags alpha: Snapshot thread flags sched: Snapshot thread flags entry: Snapshot thread flags x86: Snapshot thread flags thread_info: Add helpers to snapshot thread flags
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