user/sven/linux.git/kernel/events, branch v5.12.5

perf: Rework perf_event_exit_event()

2021-05-12T06:39:52Z

[ Upstream commit ef54c1a476aef7eef26fe13ea10dc090952c00f8 ] Make perf_event_exit_event() more robust, such that we can use it from other contexts. Specifically the up and coming remove_on_exec. For this to work we need to address a few issues. Remove_on_exec will not destroy the entire context, so we cannot rely on TASK_TOMBSTONE to disable event_function_call() and we thus have to use perf_remove_from_context(). When using perf_remove_from_context(), there's two races to consider. The first is against close(), where we can have concurrent tear-down of the event. The second is against child_list iteration, which should not find a half baked event. To address this, teach perf_remove_from_context() to special case !ctx->is_active and about DETACH_CHILD. [ elver@google.com: fix racing parent/child exit in sync_child_event(). ] Signed-off-by: Marco Elver Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/20210408103605.1676875-2-elver@google.com Signed-off-by: Sasha Levin

perf/core: Fix unconditional security_locked_down() call

2021-05-07T10:53:26Z

commit 08ef1af4de5fe7de9c6d69f1e22e51b66e385d9b upstream. Currently, the lockdown state is queried unconditionally, even though its result is used only if the PERF_SAMPLE_REGS_INTR bit is set in attr.sample_type. While that doesn't matter in case of the Lockdown LSM, it causes trouble with the SELinux's lockdown hook implementation. SELinux implements the locked_down hook with a check whether the current task's type has the corresponding "lockdown" class permission ("integrity" or "confidentiality") allowed in the policy. This means that calling the hook when the access control decision would be ignored generates a bogus permission check and audit record. Fix this by checking sample_type first and only calling the hook when its result would be honored. Fixes: b0c8fdc7fdb7 ("lockdown: Lock down perf when in confidentiality mode") Signed-off-by: Ondrej Mosnacek Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Paul Moore Link: https://lkml.kernel.org/r/20210224215628.192519-1-omosnace@redhat.com Signed-off-by: Greg Kroah-Hartman

perf/core: Flush PMU internal buffers for per-CPU events

2021-03-06T11:52:39Z

Sometimes the PMU internal buffers have to be flushed for per-CPU events during a context switch, e.g., large PEBS. Otherwise, the perf tool may report samples in locations that do not belong to the process where the samples are processed in, because PEBS does not tag samples with PID/TID. The current code only flush the buffers for a per-task event. It doesn't check a per-CPU event. Add a new event state flag, PERF_ATTACH_SCHED_CB, to indicate that the PMU internal buffers have to be flushed for this event during a context switch. Add sched_cb_entry and perf_sched_cb_usages back to track the PMU/cpuctx which is required to be flushed. Only need to invoke the sched_task() for per-CPU events in this patch. The per-task events have been handled in perf_event_context_sched_in/out already. Fixes: 9c964efa4330 ("perf/x86/intel: Drain the PEBS buffer during context switches") Reported-by: Gabriel Marin Originally-by: Namhyung Kim Signed-off-by: Kan Liang Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Ingo Molnar Link: https://lkml.kernel.org/r/20201130193842.10569-1-kan.liang@linux.intel.com

kernel: delete repeated words in comments

2021-02-26T17:41:03Z

Drop repeated words in kernel/events/. {if, the, that, with, time} Drop repeated words in kernel/locking/. {it, no, the} Drop repeated words in kernel/sched/. {in, not} Link: https://lkml.kernel.org/r/20210127023412.26292-1-rdunlap@infradead.org Signed-off-by: Randy Dunlap Acked-by: Will Deacon [kernel/locking/] Cc: Peter Zijlstra Cc: Ingo Molnar Cc: Arnaldo Carvalho de Melo Cc: Will Deacon Cc: Mathieu Desnoyers Cc: "Paul E. McKenney" Cc: Juri Lelli Cc: Vincent Guittot Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Merge tag 'perf-core-2021-02-17' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2021-02-21T20:49:32Z

Pull performance event updates from Ingo Molnar: - Add CPU-PMU support for Intel Sapphire Rapids CPUs - Extend the perf ABI with PERF_SAMPLE_WEIGHT_STRUCT, to offer two-parameter sampling event feedback. Not used yet, but is intended for Golden Cove CPU-PMU, which can provide both the instruction latency and the cache latency information for memory profiling events. - Remove experimental, default-disabled perfmon-v4 counter_freezing support that could only be enabled via a boot option. The hardware is hopelessly broken, we'd like to make sure nobody starts relying on this, as it would only end in tears. - Fix energy/power events on Intel SPR platforms - Simplify the uprobes resume_execution() logic - Misc smaller fixes. * tag 'perf-core-2021-02-17' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: perf/x86/rapl: Fix psys-energy event on Intel SPR platform perf/x86/rapl: Only check lower 32bits for RAPL energy counters perf/x86/rapl: Add msr mask support perf/x86/kvm: Add Cascade Lake Xeon steppings to isolation_ucodes[] perf/x86/intel: Support CPUID 10.ECX to disable fixed counters perf/x86/intel: Add perf core PMU support for Sapphire Rapids perf/x86/intel: Filter unsupported Topdown metrics event perf/x86/intel: Factor out intel_update_topdown_event() perf/core: Add PERF_SAMPLE_WEIGHT_STRUCT perf/intel: Remove Perfmon-v4 counter_freezing support x86/perf: Use static_call for x86_pmu.guest_get_msrs perf/x86/intel/uncore: With > 8 nodes, get pci bus die id from NUMA info perf/x86/intel/uncore: Store the logical die id instead of the physical die id. x86/kprobes: Do not decode opcode in resume_execution()

Merge tag 'sched-core-2021-02-17' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2021-02-21T20:35:04Z

Pull scheduler updates from Ingo Molnar: "Core scheduler updates: - Add CONFIG_PREEMPT_DYNAMIC: this in its current form adds the preempt=none/voluntary/full boot options (default: full), to allow distros to build a PREEMPT kernel but fall back to close to PREEMPT_VOLUNTARY (or PREEMPT_NONE) runtime scheduling behavior via a boot time selection. There's also the /debug/sched_debug switch to do this runtime. This feature is implemented via runtime patching (a new variant of static calls). The scope of the runtime patching can be best reviewed by looking at the sched_dynamic_update() function in kernel/sched/core.c. ( Note that the dynamic none/voluntary mode isn't 100% identical, for example preempt-RCU is available in all cases, plus the preempt count is maintained in all models, which has runtime overhead even with the code patching. ) The PREEMPT_VOLUNTARY/PREEMPT_NONE models, used by the vast majority of distributions, are supposed to be unaffected. - Fix ignored rescheduling after rcu_eqs_enter(). This is a bug that was found via rcutorture triggering a hang. The bug is that rcu_idle_enter() may wake up a NOCB kthread, but this happens after the last generic need_resched() check. Some cpuidle drivers fix it by chance but many others don't. In true 2020 fashion the original bug fix has grown into a 5-patch scheduler/RCU fix series plus another 16 RCU patches to address the underlying issue of missed preemption events. These are the initial fixes that should fix current incarnations of the bug. - Clean up rbtree usage in the scheduler, by providing & using the following consistent set of rbtree APIs: partial-order; less() based: - rb_add(): add a new entry to the rbtree - rb_add_cached(): like rb_add(), but for a rb_root_cached total-order; cmp() based: - rb_find(): find an entry in an rbtree - rb_find_add(): find an entry, and add if not found - rb_find_first(): find the first (leftmost) matching entry - rb_next_match(): continue from rb_find_first() - rb_for_each(): iterate a sub-tree using the previous two - Improve the SMP/NUMA load-balancer: scan for an idle sibling in a single pass. This is a 4-commit series where each commit improves one aspect of the idle sibling scan logic. - Improve the cpufreq cooling driver by getting the effective CPU utilization metrics from the scheduler - Improve the fair scheduler's active load-balancing logic by reducing the number of active LB attempts & lengthen the load-balancing interval. This improves stress-ng mmapfork performance. - Fix CFS's estimated utilization (util_est) calculation bug that can result in too high utilization values Misc updates & fixes: - Fix the HRTICK reprogramming & optimization feature - Fix SCHED_SOFTIRQ raising race & warning in the CPU offlining code - Reduce dl_add_task_root_domain() overhead - Fix uprobes refcount bug - Process pending softirqs in flush_smp_call_function_from_idle() - Clean up task priority related defines, remove *USER_*PRIO and USER_PRIO() - Simplify the sched_init_numa() deduplication sort - Documentation updates - Fix EAS bug in update_misfit_status(), which degraded the quality of energy-balancing - Smaller cleanups" * tag 'sched-core-2021-02-17' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (51 commits) sched,x86: Allow !PREEMPT_DYNAMIC entry/kvm: Explicitly flush pending rcuog wakeup before last rescheduling point entry: Explicitly flush pending rcuog wakeup before last rescheduling point rcu/nocb: Trigger self-IPI on late deferred wake up before user resume rcu/nocb: Perform deferred wake up before last idle's need_resched() check rcu: Pull deferred rcuog wake up to rcu_eqs_enter() callers sched/features: Distinguish between NORMAL and DEADLINE hrtick sched/features: Fix hrtick reprogramming sched/deadline: Reduce rq lock contention in dl_add_task_root_domain() uprobes: (Re)add missing get_uprobe() in __find_uprobe() smp: Process pending softirqs in flush_smp_call_function_from_idle() sched: Harden PREEMPT_DYNAMIC static_call: Allow module use without exposing static_call_key sched: Add /debug/sched_preempt preempt/dynamic: Support dynamic preempt with preempt= boot option preempt/dynamic: Provide irqentry_exit_cond_resched() static call preempt/dynamic: Provide preempt_schedule[_notrace]() static calls preempt/dynamic: Provide cond_resched() and might_resched() static calls preempt: Introduce CONFIG_PREEMPT_DYNAMIC static_call: Provide DEFINE_STATIC_CALL_RET0() ...

uprobes: (Re)add missing get_uprobe() in __find_uprobe()

2021-02-17T13:12:42Z

commit c6bc9bd06dff ("rbtree, uprobes: Use rbtree helpers") accidentally removed the refcount increase. Add it again. Fixes: c6bc9bd06dff ("rbtree, uprobes: Use rbtree helpers") Signed-off-by: Sven Schnelle Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Ingo Molnar Link: https://lkml.kernel.org/r/20210209150711.36778-1-svens@linux.ibm.com

rbtree, uprobes: Use rbtree helpers

2021-02-17T13:07:52Z

Reduce rbtree boilerplate by using the new helpers. Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Ingo Molnar Acked-by: Davidlohr Bueso

rbtree, perf: Use new rbtree helpers

2021-02-17T13:07:48Z

Reduce rbtree boiler plate by using the new helpers. One noteworthy change is unification of the various (partial) compare functions. We construct a subtree match by forcing the sub-order to always match, see __group_cmp(). Due to 'const' we had to touch cgroup_id(). Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Ingo Molnar Acked-by: Tejun Heo Acked-by: Davidlohr Bueso

perf/core: Add PERF_SAMPLE_WEIGHT_STRUCT

2021-02-01T14:31:36Z

Current PERF_SAMPLE_WEIGHT sample type is very useful to expresses the cost of an action represented by the sample. This allows the profiler to scale the samples to be more informative to the programmer. It could also help to locate a hotspot, e.g., when profiling by memory latencies, the expensive load appear higher up in the histograms. But current PERF_SAMPLE_WEIGHT sample type is solely determined by one factor. This could be a problem, if users want two or more factors to contribute to the weight. For example, Golden Cove core PMU can provide both the instruction latency and the cache Latency information as factors for the memory profiling. For current X86 platforms, although meminfo::latency is defined as a u64, only the lower 32 bits include the valid data in practice (No memory access could last than 4G cycles). The higher 32 bits can be used to store new factors. Add a new sample type, PERF_SAMPLE_WEIGHT_STRUCT, to indicate the new sample weight structure. It shares the same space as the PERF_SAMPLE_WEIGHT sample type. Users can apply either the PERF_SAMPLE_WEIGHT sample type or the PERF_SAMPLE_WEIGHT_STRUCT sample type to retrieve the sample weight, but they cannot apply both sample types simultaneously. Currently, only X86 and PowerPC use the PERF_SAMPLE_WEIGHT sample type. - For PowerPC, there is nothing changed for the PERF_SAMPLE_WEIGHT sample type. There is no effect for the new PERF_SAMPLE_WEIGHT_STRUCT sample type. PowerPC can re-struct the weight field similarly later. - For X86, the same value will be dumped for the PERF_SAMPLE_WEIGHT sample type or the PERF_SAMPLE_WEIGHT_STRUCT sample type for now. The following patches will apply the new factors for the PERF_SAMPLE_WEIGHT_STRUCT sample type. The field in the union perf_sample_weight should be shared among different architectures. A generic name is required, but it's hard to abstract a name that applies to all architectures. For example, on X86, the fields are to store all kinds of latency. While on PowerPC, it stores MMCRA[TECX/TECM], which should not be latency. So a general name prefix 'var$NUM' is used here. Suggested-by: Peter Zijlstra (Intel) Signed-off-by: Kan Liang Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/1611873611-156687-2-git-send-email-kan.liang@linux.intel.com