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2021-02-19cpufreq: schedutil: Remove needless sg_policy parameter from ↵Yue Hu1-7/+5
ignore_dl_rate_limit() Since sg_policy is a member of struct sugov_cpu. Also remove the local variable in sugov_update_single_common() to make the code more clean. Signed-off-by: Yue Hu <huyue2@yulong.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> [ rjw: Minor subject edits ] Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2021-02-17entry/kvm: Explicitly flush pending rcuog wakeup before last rescheduling pointFrederic Weisbecker2-10/+35
Following the idle loop model, cleanly check for pending rcuog wakeup before the last rescheduling point upon resuming to guest mode. This way we can avoid to do it from rcu_user_enter() with the last resort self-IPI hack that enforces rescheduling. Suggested-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20210131230548.32970-6-frederic@kernel.org
2021-02-17entry: Explicitly flush pending rcuog wakeup before last rescheduling pointFrederic Weisbecker2-5/+14
Following the idle loop model, cleanly check for pending rcuog wakeup before the last rescheduling point on resuming to user mode. This way we can avoid to do it from rcu_user_enter() with the last resort self-IPI hack that enforces rescheduling. Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20210131230548.32970-5-frederic@kernel.org
2021-02-17rcu/nocb: Trigger self-IPI on late deferred wake up before user resumeFrederic Weisbecker3-11/+37
Entering RCU idle mode may cause a deferred wake up of an RCU NOCB_GP kthread (rcuog) to be serviced. Unfortunately the call to rcu_user_enter() is already past the last rescheduling opportunity before we resume to userspace or to guest mode. We may escape there with the woken task ignored. The ultimate resort to fix every callsites is to trigger a self-IPI (nohz_full depends on arch to implement arch_irq_work_raise()) that will trigger a reschedule on IRQ tail or guest exit. Eventually every site that want a saner treatment will need to carefully place a call to rcu_nocb_flush_deferred_wakeup() before the last explicit need_resched() check upon resume. Fixes: 96d3fd0d315a (rcu: Break call_rcu() deadlock involving scheduler and perf) Reported-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20210131230548.32970-4-frederic@kernel.org
2021-02-17rcu/nocb: Perform deferred wake up before last idle's need_resched() checkFrederic Weisbecker3-3/+6
Entering RCU idle mode may cause a deferred wake up of an RCU NOCB_GP kthread (rcuog) to be serviced. Usually a local wake up happening while running the idle task is handled in one of the need_resched() checks carefully placed within the idle loop that can break to the scheduler. Unfortunately the call to rcu_idle_enter() is already beyond the last generic need_resched() check and we may halt the CPU with a resched request unhandled, leaving the task hanging. Fix this with splitting the rcuog wakeup handling from rcu_idle_enter() and place it before the last generic need_resched() check in the idle loop. It is then assumed that no call to call_rcu() will be performed after that in the idle loop until the CPU is put in low power mode. Fixes: 96d3fd0d315a (rcu: Break call_rcu() deadlock involving scheduler and perf) Reported-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20210131230548.32970-3-frederic@kernel.org
2021-02-17rcu: Pull deferred rcuog wake up to rcu_eqs_enter() callersFrederic Weisbecker1-1/+10
Deferred wakeup of rcuog kthreads upon RCU idle mode entry is going to be handled differently whether initiated by idle, user or guest. Prepare with pulling that control up to rcu_eqs_enter() callers. Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20210131230548.32970-2-frederic@kernel.org
2021-02-17sched/features: Distinguish between NORMAL and DEADLINE hrtickJuri Lelli5-7/+30
The HRTICK feature has traditionally been servicing configurations that need precise preemptions point for NORMAL tasks. More recently, the feature has been extended to also service DEADLINE tasks with stringent runtime enforcement needs (e.g., runtime < 1ms with HZ=1000). Enabling HRTICK sched feature currently enables the additional timer and task tick for both classes, which might introduced undesired overhead for no additional benefit if one needed it only for one of the cases. Separate HRTICK sched feature in two (and leave the traditional case name unmodified) so that it can be selectively enabled when needed. With: $ echo HRTICK > /sys/kernel/debug/sched_features the NORMAL/fair hrtick gets enabled. With: $ echo HRTICK_DL > /sys/kernel/debug/sched_features the DEADLINE hrtick gets enabled. Signed-off-by: Juri Lelli <juri.lelli@redhat.com> Signed-off-by: Luis Claudio R. Goncalves <lgoncalv@redhat.com> Signed-off-by: Daniel Bristot de Oliveira <bristot@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lkml.kernel.org/r/20210208073554.14629-3-juri.lelli@redhat.com
2021-02-17sched/features: Fix hrtick reprogrammingJuri Lelli2-5/+4
Hung tasks and RCU stall cases were reported on systems which were not 100% busy. Investigation of such unexpected cases (no sign of potential starvation caused by tasks hogging the system) pointed out that the periodic sched tick timer wasn't serviced anymore after a certain point and that caused all machinery that depends on it (timers, RCU, etc.) to stop working as well. This issues was however only reproducible if HRTICK was enabled. Looking at core dumps it was found that the rbtree of the hrtimer base used also for the hrtick was corrupted (i.e. next as seen from the base root and actual leftmost obtained by traversing the tree are different). Same base is also used for periodic tick hrtimer, which might get "lost" if the rbtree gets corrupted. Much alike what described in commit 1f71addd34f4c ("tick/sched: Do not mess with an enqueued hrtimer") there is a race window between hrtimer_set_expires() in hrtick_start and hrtimer_start_expires() in __hrtick_restart() in which the former might be operating on an already queued hrtick hrtimer, which might lead to corruption of the base. Use hrtick_start() (which removes the timer before enqueuing it back) to ensure hrtick hrtimer reprogramming is entirely guarded by the base lock, so that no race conditions can occur. Signed-off-by: Juri Lelli <juri.lelli@redhat.com> Signed-off-by: Luis Claudio R. Goncalves <lgoncalv@redhat.com> Signed-off-by: Daniel Bristot de Oliveira <bristot@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lkml.kernel.org/r/20210208073554.14629-2-juri.lelli@redhat.com
2021-02-17sched/deadline: Reduce rq lock contention in dl_add_task_root_domain()Dietmar Eggemann1-4/+7
dl_add_task_root_domain() is called during sched domain rebuild: rebuild_sched_domains_locked() partition_and_rebuild_sched_domains() rebuild_root_domains() for all top_cpuset descendants: update_tasks_root_domain() for all tasks of cpuset: dl_add_task_root_domain() Change it so that only the task pi lock is taken to check if the task has a SCHED_DEADLINE (DL) policy. In case that p is a DL task take the rq lock as well to be able to safely de-reference root domain's DL bandwidth structure. Most of the tasks will have another policy (namely SCHED_NORMAL) and can now bail without taking the rq lock. One thing to note here: Even in case that there aren't any DL user tasks, a slow frequency switching system with cpufreq gov schedutil has a DL task (sugov) per frequency domain running which participates in DL bandwidth management. Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Reviewed-by: Quentin Perret <qperret@google.com> Reviewed-by: Valentin Schneider <valentin.schneider@arm.com> Reviewed-by: Daniel Bristot de Oliveira <bristot@redhat.com> Acked-by: Juri Lelli <juri.lelli@redhat.com> Link: https://lkml.kernel.org/r/20210119083542.19856-1-dietmar.eggemann@arm.com
2021-02-17uprobes: (Re)add missing get_uprobe() in __find_uprobe()Sven Schnelle1-1/+1
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 <svens@linux.ibm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lkml.kernel.org/r/20210209150711.36778-1-svens@linux.ibm.com
2021-02-17smp: Process pending softirqs in flush_smp_call_function_from_idle()Sebastian Andrzej Siewior1-0/+4
send_call_function_single_ipi() may wake an idle CPU without sending an IPI. The woken up CPU will process the SMP-functions in flush_smp_call_function_from_idle(). Any raised softirq from within the SMP-function call will not be processed. Should the CPU have no tasks assigned, then it will go back to idle with pending softirqs and the NOHZ will rightfully complain. Process pending softirqs on return from flush_smp_call_function_queue(). Fixes: b2a02fc43a1f4 ("smp: Optimize send_call_function_single_ipi()") Reported-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lkml.kernel.org/r/20210123201027.3262800-2-bigeasy@linutronix.de
2021-02-17sched: Harden PREEMPT_DYNAMICPeter Zijlstra1-4/+4
Use the new EXPORT_STATIC_CALL_TRAMP() / static_call_mod() to unexport the static_call_key for the PREEMPT_DYNAMIC calls such that modules can no longer update these calls. Having modules change/hi-jack the preemption calls would be horrible. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org>
2021-02-17static_call: Allow module use without exposing static_call_keyJosh Poimboeuf1-2/+53
When exporting static_call_key; with EXPORT_STATIC_CALL*(), the module can use static_call_update() to change the function called. This is not desirable in general. Not exporting static_call_key however also disallows usage of static_call(), since objtool needs the key to construct the static_call_site. Solve this by allowing objtool to create the static_call_site using the trampoline address when it builds a module and cannot find the static_call_key symbol. The module loader will then try and map the trampole back to a key before it constructs the normal sites list. Doing this requires a trampoline -> key associsation, so add another magic section that keeps those. Originally-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lkml.kernel.org/r/20210127231837.ifddpn7rhwdaepiu@treble
2021-02-17sched: Add /debug/sched_preemptPeter Zijlstra1-9/+126
Add a debugfs file to muck about with the preempt mode at runtime. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lkml.kernel.org/r/YAsGiUYf6NyaTplX@hirez.programming.kicks-ass.net
2021-02-17preempt/dynamic: Support dynamic preempt with preempt= boot optionPeter Zijlstra (Intel)1-1/+67
Support the preempt= boot option and patch the static call sites accordingly. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lkml.kernel.org/r/20210118141223.123667-9-frederic@kernel.org
2021-02-17preempt/dynamic: Provide irqentry_exit_cond_resched() static callPeter Zijlstra (Intel)1-1/+9
Provide static call to control IRQ preemption (called in CONFIG_PREEMPT) so that we can override its behaviour when preempt= is overriden. Since the default behaviour is full preemption, its call is initialized to provide IRQ preemption when preempt= isn't passed. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lkml.kernel.org/r/20210118141223.123667-8-frederic@kernel.org
2021-02-17preempt/dynamic: Provide preempt_schedule[_notrace]() static callsPeter Zijlstra (Intel)1-0/+12
Provide static calls to control preempt_schedule[_notrace]() (called in CONFIG_PREEMPT) so that we can override their behaviour when preempt= is overriden. Since the default behaviour is full preemption, both their calls are initialized to the arch provided wrapper, if any. [fweisbec: only define static calls when PREEMPT_DYNAMIC, make it less dependent on x86 with __preempt_schedule_func] Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lkml.kernel.org/r/20210118141223.123667-7-frederic@kernel.org
2021-02-17preempt/dynamic: Provide cond_resched() and might_resched() static callsPeter Zijlstra (Intel)1-3/+13
Provide static calls to control cond_resched() (called in !CONFIG_PREEMPT) and might_resched() (called in CONFIG_PREEMPT_VOLUNTARY) to that we can override their behaviour when preempt= is overriden. Since the default behaviour is full preemption, both their calls are ignored when preempt= isn't passed. [fweisbec: branch might_resched() directly to __cond_resched(), only define static calls when PREEMPT_DYNAMIC] Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lkml.kernel.org/r/20210118141223.123667-6-frederic@kernel.org
2021-02-17preempt: Introduce CONFIG_PREEMPT_DYNAMICMichal Hocko1-0/+19
Preemption mode selection is currently hardcoded on Kconfig choices. Introduce a dedicated option to tune preemption flavour at boot time, This will be only available on architectures efficiently supporting static calls in order not to tempt with the feature against additional overhead that might be prohibitive or undesirable. CONFIG_PREEMPT_DYNAMIC is automatically selected by CONFIG_PREEMPT if the architecture provides the necessary support (CONFIG_STATIC_CALL_INLINE, CONFIG_GENERIC_ENTRY, and provide with __preempt_schedule_function() / __preempt_schedule_notrace_function()). Suggested-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Frederic Weisbecker <frederic@kernel.org> [peterz: relax requirement to HAVE_STATIC_CALL] Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lkml.kernel.org/r/20210118141223.123667-5-frederic@kernel.org
2021-02-17static_call/x86: Add __static_call_return0()Peter Zijlstra1-0/+5
Provide a stub function that return 0 and wire up the static call site patching to replace the CALL with a single 5 byte instruction that clears %RAX, the return value register. The function can be cast to any function pointer type that has a single %RAX return (including pointers). Also provide a version that returns an int for convenience. We are clearing the entire %RAX register in any case, whether the return value is 32 or 64 bits, since %RAX is always a scratch register anyway. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lkml.kernel.org/r/20210118141223.123667-2-frederic@kernel.org
2021-02-17sched/core: Update task_prio() function headerDietmar Eggemann1-2/+6
The description of the RT offset and the values for 'normal' tasks needs update. Moreover there are DL tasks now. task_prio() has to stay like it is to guarantee compatibility with the /proc/<pid>/stat priority field: # cat /proc/<pid>/stat | awk '{ print $18; }' Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lkml.kernel.org/r/20210128131040.296856-4-dietmar.eggemann@arm.com
2021-02-17sched: Remove USER_PRIO, TASK_USER_PRIO and MAX_USER_PRIODietmar Eggemann1-1/+1
The only remaining use of MAX_USER_PRIO (and USER_PRIO) is the SCALE_PRIO() definition in the PowerPC Cell architecture's Synergistic Processor Unit (SPU) scheduler. TASK_USER_PRIO isn't used anymore. Commit fe443ef2ac42 ("[POWERPC] spusched: Dynamic timeslicing for SCHED_OTHER") copied SCALE_PRIO() from the task scheduler in v2.6.23. Commit a4ec24b48dde ("sched: tidy up SCHED_RR") removed it from the task scheduler in v2.6.24. Commit 3ee237dddcd8 ("sched/prio: Add 3 macros of MAX_NICE, MIN_NICE and NICE_WIDTH in prio.h") introduced NICE_WIDTH much later. With: MAX_USER_PRIO = USER_PRIO(MAX_PRIO) = MAX_PRIO - MAX_RT_PRIO MAX_PRIO = MAX_RT_PRIO + NICE_WIDTH MAX_USER_PRIO = MAX_RT_PRIO + NICE_WIDTH - MAX_RT_PRIO MAX_USER_PRIO = NICE_WIDTH MAX_USER_PRIO can be replaced by NICE_WIDTH to be able to remove all the {*_}USER_PRIO defines. Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lkml.kernel.org/r/20210128131040.296856-3-dietmar.eggemann@arm.com
2021-02-17sched: Remove MAX_USER_RT_PRIODietmar Eggemann1-4/+3
Commit d46523ea32a7 ("[PATCH] fix MAX_USER_RT_PRIO and MAX_RT_PRIO") was introduced due to a a small time period in which the realtime patch set was using different values for MAX_USER_RT_PRIO and MAX_RT_PRIO. This is no longer true, i.e. now MAX_RT_PRIO == MAX_USER_RT_PRIO. Get rid of MAX_USER_RT_PRIO and make everything use MAX_RT_PRIO instead. Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lkml.kernel.org/r/20210128131040.296856-2-dietmar.eggemann@arm.com
2021-02-17sched/topology: Fix sched_domain_topology_level alloc in sched_init_numa()Dietmar Eggemann1-1/+1
Commit "sched/topology: Make sched_init_numa() use a set for the deduplicating sort" allocates 'i + nr_levels (level)' instead of 'i + nr_levels + 1' sched_domain_topology_level. This led to an Oops (on Arm64 juno with CONFIG_SCHED_DEBUG): sched_init_domains build_sched_domains() __free_domain_allocs() __sdt_free() { ... for_each_sd_topology(tl) ... sd = *per_cpu_ptr(sdd->sd, j); <-- ... } Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Tested-by: Vincent Guittot <vincent.guittot@linaro.org> Tested-by: Barry Song <song.bao.hua@hisilicon.com> Link: https://lkml.kernel.org/r/6000e39e-7d28-c360-9cd6-8798fd22a9bf@arm.com
2021-02-17rbtree, rtmutex: Use rb_add_cached()Peter Zijlstra1-36/+18
Reduce rbtree boiler plate by using the new helpers. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Acked-by: Davidlohr Bueso <dbueso@suse.de>
2021-02-17rbtree, uprobes: Use rbtree helpersPeter Zijlstra1-41/+39
Reduce rbtree boilerplate by using the new helpers. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Acked-by: Davidlohr Bueso <dbueso@suse.de>
2021-02-17rbtree, perf: Use new rbtree helpersPeter Zijlstra1-105/+90
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) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Acked-by: Tejun Heo <tj@kernel.org> Acked-by: Davidlohr Bueso <dbueso@suse.de>
2021-02-17rbtree, sched/deadline: Use rb_add_cached()Peter Zijlstra1-49/+28
Reduce rbtree boiler plate by using the new helpers. Make rb_add_cached() / rb_erase_cached() return a pointer to the leftmost node to aid in updating additional state. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Acked-by: Davidlohr Bueso <dbueso@suse.de>
2021-02-17rbtree, sched/fair: Use rb_add_cached()Peter Zijlstra1-32/+14
Reduce rbtree boiler plate by using the new helper function. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Acked-by: Davidlohr Bueso <dbueso@suse.de>
2021-02-17sched/fair: Merge select_idle_core/cpu()Mel Gorman1-40/+59
Both select_idle_core() and select_idle_cpu() do a loop over the same cpumask. Observe that by clearing the already visited CPUs, we can fold the iteration and iterate a core at a time. All we need to do is remember any non-idle CPU we encountered while scanning for an idle core. This way we'll only iterate every CPU once. Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org> Link: https://lkml.kernel.org/r/20210127135203.19633-5-mgorman@techsingularity.net
2021-02-17sched/fair: Remove select_idle_smt()Mel Gorman1-30/+0
In order to make the next patch more readable, and to quantify the actual effectiveness of this pass, start by removing it. Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org> Link: https://lkml.kernel.org/r/20210125085909.4600-4-mgorman@techsingularity.net
2021-02-17Merge tag 'v5.11' into sched/core, to pick up fixes & refresh the branchIngo Molnar47-300/+465
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2021-02-17Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netDavid S. Miller1-4/+6
2021-02-17Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-nextDavid S. Miller15-341/+1193
Daniel Borkmann says: ==================== pull-request: bpf-next 2021-02-16 The following pull-request contains BPF updates for your *net-next* tree. There's a small merge conflict between 7eeba1706eba ("tcp: Add receive timestamp support for receive zerocopy.") from net-next tree and 9cacf81f8161 ("bpf: Remove extra lock_sock for TCP_ZEROCOPY_RECEIVE") from bpf-next tree. Resolve as follows: [...] lock_sock(sk); err = tcp_zerocopy_receive(sk, &zc, &tss); err = BPF_CGROUP_RUN_PROG_GETSOCKOPT_KERN(sk, level, optname, &zc, &len, err); release_sock(sk); [...] We've added 116 non-merge commits during the last 27 day(s) which contain a total of 156 files changed, 5662 insertions(+), 1489 deletions(-). The main changes are: 1) Adds support of pointers to types with known size among global function args to overcome the limit on max # of allowed args, from Dmitrii Banshchikov. 2) Add bpf_iter for task_vma which can be used to generate information similar to /proc/pid/maps, from Song Liu. 3) Enable bpf_{g,s}etsockopt() from all sock_addr related program hooks. Allow rewriting bind user ports from BPF side below the ip_unprivileged_port_start range, both from Stanislav Fomichev. 4) Prevent recursion on fentry/fexit & sleepable programs and allow map-in-map as well as per-cpu maps for the latter, from Alexei Starovoitov. 5) Add selftest script to run BPF CI locally. Also enable BPF ringbuffer for sleepable programs, both from KP Singh. 6) Extend verifier to enable variable offset read/write access to the BPF program stack, from Andrei Matei. 7) Improve tc & XDP MTU handling and add a new bpf_check_mtu() helper to query device MTU from programs, from Jesper Dangaard Brouer. 8) Allow bpf_get_socket_cookie() helper also be called from [sleepable] BPF tracing programs, from Florent Revest. 9) Extend x86 JIT to pad JMPs with NOPs for helping image to converge when otherwise too many passes are required, from Gary Lin. 10) Verifier fixes on atomics with BPF_FETCH as well as function-by-function verification both related to zero-extension handling, from Ilya Leoshkevich. 11) Better kernel build integration of resolve_btfids tool, from Jiri Olsa. 12) Batch of AF_XDP selftest cleanups and small performance improvement for libbpf's xsk map redirect for newer kernels, from Björn Töpel. 13) Follow-up BPF doc and verifier improvements around atomics with BPF_FETCH, from Brendan Jackman. 14) Permit zero-sized data sections e.g. if ELF .rodata section contains read-only data from local variables, from Yonghong Song. 15) veth driver skb bulk-allocation for ndo_xdp_xmit, from Lorenzo Bianconi. ==================== Signed-off-by: David S. Miller <davem@davemloft.net>
2021-02-16kcmp: Support selection of SYS_kcmp without CHECKPOINT_RESTOREChris Wilson1-1/+1
Userspace has discovered the functionality offered by SYS_kcmp and has started to depend upon it. In particular, Mesa uses SYS_kcmp for os_same_file_description() in order to identify when two fd (e.g. device or dmabuf) point to the same struct file. Since they depend on it for core functionality, lift SYS_kcmp out of the non-default CONFIG_CHECKPOINT_RESTORE into the selectable syscall category. Rasmus Villemoes also pointed out that systemd uses SYS_kcmp to deduplicate the per-service file descriptor store. Note that some distributions such as Ubuntu are already enabling CHECKPOINT_RESTORE in their configs and so, by extension, SYS_kcmp. References: https://gitlab.freedesktop.org/drm/intel/-/issues/3046 Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Kees Cook <keescook@chromium.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Will Drewry <wad@chromium.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Dave Airlie <airlied@gmail.com> Cc: Daniel Vetter <daniel@ffwll.ch> Cc: Lucas Stach <l.stach@pengutronix.de> Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk> Cc: Cyrill Gorcunov <gorcunov@gmail.com> Cc: stable@vger.kernel.org Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> # DRM depends on kcmp Acked-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> # systemd uses kcmp Reviewed-by: Cyrill Gorcunov <gorcunov@gmail.com> Reviewed-by: Kees Cook <keescook@chromium.org> Acked-by: Thomas Zimmermann <tzimmermann@suse.de> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> Link: https://patchwork.freedesktop.org/patch/msgid/20210205220012.1983-1-chris@chris-wilson.co.uk
2021-02-16kbuild: simplify access to the kernel's versionSasha Levin1-1/+1
Instead of storing the version in a single integer and having various kernel (and userspace) code how it's constructed, export individual (major, patchlevel, sublevel) components and simplify kernel code that uses it. This should also make it easier on userspace. Signed-off-by: Sasha Levin <sashal@kernel.org> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-02-16bpf: Clear subreg_def for global function return valuesIlya Leoshkevich1-1/+2
test_global_func4 fails on s390 as reported by Yauheni in [1]. The immediate problem is that the zext code includes the instruction, whose result needs to be zero-extended, into the zero-extension patchlet, and if this instruction happens to be a branch, then its delta is not adjusted. As a result, the verifier rejects the program later. However, according to [2], as far as the verifier's algorithm is concerned and as specified by the insn_no_def() function, branching insns do not define anything. This includes call insns, even though one might argue that they define %r0. This means that the real problem is that zero extension kicks in at all. This happens because clear_caller_saved_regs() sets BPF_REG_0's subreg_def after global function calls. This can be fixed in many ways; this patch mimics what helper function call handling already does. [1] https://lore.kernel.org/bpf/20200903140542.156624-1-yauheni.kaliuta@redhat.com/ [2] https://lore.kernel.org/bpf/CAADnVQ+2RPKcftZw8d+B1UwB35cpBhpF5u3OocNh90D9pETPwg@mail.gmail.com/ Fixes: 51c39bb1d5d1 ("bpf: Introduce function-by-function verification") Reported-by: Yauheni Kaliuta <yauheni.kaliuta@redhat.com> Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20210212040408.90109-1-iii@linux.ibm.com
2021-02-15Merge branches 'powercap' and 'pm-misc'Rafael J. Wysocki1-8/+4
* powercap: powercap: intel_rapl: Use topology interface in rapl_init_domains() powercap: intel_rapl: Use topology interface in rapl_add_package() powercap/intel_rapl: add support for AlderLake Mobile powercap/drivers/dtpm: Fix size of object being allocated powercap/drivers/dtpm: Fix an IS_ERR() vs NULL check powercap/drivers/dtpm: Fix some missing unlock bugs powercap/drivers/dtpm: Fix a double shift bug powercap/drivers/dtpm: Fix __udivdi3 and __aeabi_uldivmod unresolved symbols powercap/drivers/dtpm: Add CPU energy model based support powercap/drivers/dtpm: Add API for dynamic thermal power management Documentation/powercap/dtpm: Add documentation for dtpm units: Add Watt units * pm-misc: PM: Kconfig: remove unneeded "default n" options PM: EM: update Kconfig description and drop "default n" option
2021-02-15Merge branches 'pm-sleep', 'pm-core', 'pm-domains' and 'pm-clk'Rafael J. Wysocki2-2/+2
* pm-sleep: PM: sleep: Constify static struct attribute_group PM: sleep: Use dev_printk() when possible PM: sleep: No need to check PF_WQ_WORKER in thaw_kernel_threads() * pm-core: PM: runtime: Fix typos and grammar PM: runtime: Fix resposible -> responsible in runtime.c * pm-domains: PM: domains: Simplify the calculation of variables PM: domains: Add "performance" column to debug summary PM: domains: Make of_genpd_add_subdomain() return -EPROBE_DEFER PM: domains: Make set_performance_state() callback optional PM: domains: use device's next wakeup to determine domain idle state PM: domains: inform PM domain of a device's next wakeup * pm-clk: PM: clk: make PM clock layer compatible with clocks that must sleep
2021-02-13Merge branch 'for-5.11-fixes' of ↵Linus Torvalds2-1/+6
git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup Pull cgroup fixes from Tejun Heo: "Two cgroup fixes: - fix a NULL deref when trying to poll PSI in the root cgroup - fix confusing controller parsing corner case when mounting cgroup v1 hierarchies And doc / maintainer file updates" * 'for-5.11-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: cgroup: update PSI file description in docs cgroup: fix psi monitor for root cgroup MAINTAINERS: Update my email address MAINTAINERS: Remove stale URLs for cpuset cgroup-v1: add disabled controller check in cgroup1_parse_param()
2021-02-13driver core: lift dma_default_coherent into common codeChristoph Hellwig2-3/+2
Lift the dma_default_coherent variable from the mips architecture code to the driver core. This allows an architecture to sdefault all device to be DMA coherent at run time, even if the kernel is build with support for DMA noncoherent device. By allowing device_initialize to set the ->dma_coherent field to this default the amount of arch hooks required for this behavior can be greatly reduced. Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
2021-02-13bpf: Support pointers in global func argsDmitrii Banshchikov2-10/+75
Add an ability to pass a pointer to a type with known size in arguments of a global function. Such pointers may be used to overcome the limit on the maximum number of arguments, avoid expensive and tricky workarounds and to have multiple output arguments. A referenced type may contain pointers but indirect access through them isn't supported. The implementation consists of two parts. If a global function has an argument that is a pointer to a type with known size then: 1) In btf_check_func_arg_match(): check that the corresponding register points to NULL or to a valid memory region that is large enough to contain the expected argument's type. 2) In btf_prepare_func_args(): set the corresponding register type to PTR_TO_MEM_OR_NULL and its size to the size of the expected type. Only global functions are supported because allowance of pointers for static functions might break validation. Consider the following scenario. A static function has a pointer argument. A caller passes pointer to its stack memory. Because the callee can change referenced memory verifier cannot longer assume any particular slot type of the caller's stack memory hence the slot type is changed to SLOT_MISC. If there is an operation that relies on slot type other than SLOT_MISC then verifier won't be able to infer safety of the operation. When verifier sees a static function that has a pointer argument different from PTR_TO_CTX then it skips arguments check and continues with "inline" validation with more information available. The operation that relies on the particular slot type now succeeds. Because global functions were not allowed to have pointer arguments different from PTR_TO_CTX it's not possible to break existing and valid code. Signed-off-by: Dmitrii Banshchikov <me@ubique.spb.ru> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20210212205642.620788-4-me@ubique.spb.ru
2021-02-13bpf: Extract nullable reg type conversion into a helper functionDmitrii Banshchikov1-31/+52
Extract conversion from a register's nullable type to a type with a value. The helper will be used in mark_ptr_not_null_reg(). Signed-off-by: Dmitrii Banshchikov <me@ubique.spb.ru> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20210212205642.620788-3-me@ubique.spb.ru
2021-02-13bpf: Rename bpf_reg_state variablesDmitrii Banshchikov1-8/+12
Using "reg" for an array of bpf_reg_state and "reg[i + 1]" for an individual bpf_reg_state is error-prone and verbose. Use "regs" for the former and "reg" for the latter as other code nearby does. Signed-off-by: Dmitrii Banshchikov <me@ubique.spb.ru> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20210212205642.620788-2-me@ubique.spb.ru
2021-02-13bpf: Fix truncation handling for mod32 dst reg wrt zeroDaniel Borkmann1-4/+6
Recently noticed that when mod32 with a known src reg of 0 is performed, then the dst register is 32-bit truncated in verifier: 0: R1=ctx(id=0,off=0,imm=0) R10=fp0 0: (b7) r0 = 0 1: R0_w=inv0 R1=ctx(id=0,off=0,imm=0) R10=fp0 1: (b7) r1 = -1 2: R0_w=inv0 R1_w=inv-1 R10=fp0 2: (b4) w2 = -1 3: R0_w=inv0 R1_w=inv-1 R2_w=inv4294967295 R10=fp0 3: (9c) w1 %= w0 4: R0_w=inv0 R1_w=inv(id=0,umax_value=4294967295,var_off=(0x0; 0xffffffff)) R2_w=inv4294967295 R10=fp0 4: (b7) r0 = 1 5: R0_w=inv1 R1_w=inv(id=0,umax_value=4294967295,var_off=(0x0; 0xffffffff)) R2_w=inv4294967295 R10=fp0 5: (1d) if r1 == r2 goto pc+1 R0_w=inv1 R1_w=inv(id=0,umax_value=4294967295,var_off=(0x0; 0xffffffff)) R2_w=inv4294967295 R10=fp0 6: R0_w=inv1 R1_w=inv(id=0,umax_value=4294967295,var_off=(0x0; 0xffffffff)) R2_w=inv4294967295 R10=fp0 6: (b7) r0 = 2 7: R0_w=inv2 R1_w=inv(id=0,umax_value=4294967295,var_off=(0x0; 0xffffffff)) R2_w=inv4294967295 R10=fp0 7: (95) exit 7: R0=inv1 R1=inv(id=0,umin_value=4294967295,umax_value=4294967295,var_off=(0x0; 0xffffffff)) R2=inv4294967295 R10=fp0 7: (95) exit However, as a runtime result, we get 2 instead of 1, meaning the dst register does not contain (u32)-1 in this case. The reason is fairly straight forward given the 0 test leaves the dst register as-is: # ./bpftool p d x i 23 0: (b7) r0 = 0 1: (b7) r1 = -1 2: (b4) w2 = -1 3: (16) if w0 == 0x0 goto pc+1 4: (9c) w1 %= w0 5: (b7) r0 = 1 6: (1d) if r1 == r2 goto pc+1 7: (b7) r0 = 2 8: (95) exit This was originally not an issue given the dst register was marked as completely unknown (aka 64 bit unknown). However, after 468f6eafa6c4 ("bpf: fix 32-bit ALU op verification") the verifier casts the register output to 32 bit, and hence it becomes 32 bit unknown. Note that for the case where the src register is unknown, the dst register is marked 64 bit unknown. After the fix, the register is truncated by the runtime and the test passes: # ./bpftool p d x i 23 0: (b7) r0 = 0 1: (b7) r1 = -1 2: (b4) w2 = -1 3: (16) if w0 == 0x0 goto pc+2 4: (9c) w1 %= w0 5: (05) goto pc+1 6: (bc) w1 = w1 7: (b7) r0 = 1 8: (1d) if r1 == r2 goto pc+1 9: (b7) r0 = 2 10: (95) exit Semantics also match with {R,W}x mod{64,32} 0 -> {R,W}x. Invalid div has always been {R,W}x div{64,32} 0 -> 0. Rewrites are as follows: mod32: mod64: (16) if w0 == 0x0 goto pc+2 (15) if r0 == 0x0 goto pc+1 (9c) w1 %= w0 (9f) r1 %= r0 (05) goto pc+1 (bc) w1 = w1 Fixes: 468f6eafa6c4 ("bpf: fix 32-bit ALU op verification") Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Reviewed-by: John Fastabend <john.fastabend@gmail.com> Acked-by: Alexei Starovoitov <ast@kernel.org>
2021-02-13bpf, devmap: Use GFP_KERNEL for xdp bulk queue allocationJun'ichi Nomura1-3/+1
The devmap bulk queue is allocated with GFP_ATOMIC and the allocation may fail if there is no available space in existing percpu pool. Since commit 75ccae62cb8d42 ("xdp: Move devmap bulk queue into struct net_device") moved the bulk queue allocation to NETDEV_REGISTER callback, whose context is allowed to sleep, use GFP_KERNEL instead of GFP_ATOMIC to let percpu allocator extend the pool when needed and avoid possible failure of netdev registration. As the required alignment is natural, we can simply use alloc_percpu(). Fixes: 75ccae62cb8d42 ("xdp: Move devmap bulk queue into struct net_device") Signed-off-by: Jun'ichi Nomura <junichi.nomura@nec.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Cc: Toke Høiland-Jørgensen <toke@redhat.com> Link: https://lore.kernel.org/bpf/20210209082451.GA44021@jeru.linux.bs1.fc.nec.co.jp
2021-02-13bpf: Fix an unitialized value in bpf_iterYonghong Song1-1/+1
Commit 15d83c4d7cef ("bpf: Allow loading of a bpf_iter program") cached btf_id in struct bpf_iter_target_info so later on if it can be checked cheaply compared to checking registered names. syzbot found a bug that uninitialized value may occur to bpf_iter_target_info->btf_id. This is because we allocated bpf_iter_target_info structure with kmalloc and never initialized field btf_id afterwards. This uninitialized btf_id is typically compared to a u32 bpf program func proto btf_id, and the chance of being equal is extremely slim. This patch fixed the issue by using kzalloc which will also prevent future likely instances due to adding new fields. Fixes: 15d83c4d7cef ("bpf: Allow loading of a bpf_iter program") Reported-by: syzbot+580f4f2a272e452d55cb@syzkaller.appspotmail.com Signed-off-by: Yonghong Song <yhs@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20210212005926.2875002-1-yhs@fb.com
2021-02-12bpf: Allow bpf_d_path in bpf_iter programSong Liu1-0/+4
task_file and task_vma iter programs have access to file->f_path. Enable bpf_d_path to print paths of these file. Signed-off-by: Song Liu <songliubraving@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/bpf/20210212183107.50963-3-songliubraving@fb.com
2021-02-12bpf: Introduce task_vma bpf_iterSong Liu1-1/+266
Introduce task_vma bpf_iter to print memory information of a process. It can be used to print customized information similar to /proc/<pid>/maps. Current /proc/<pid>/maps and /proc/<pid>/smaps provide information of vma's of a process. However, these information are not flexible enough to cover all use cases. For example, if a vma cover mixed 2MB pages and 4kB pages (x86_64), there is no easy way to tell which address ranges are backed by 2MB pages. task_vma solves the problem by enabling the user to generate customize information based on the vma (and vma->vm_mm, vma->vm_file, etc.). To access the vma safely in the BPF program, task_vma iterator holds target mmap_lock while calling the BPF program. If the mmap_lock is contended, task_vma unlocks mmap_lock between iterations to unblock the writer(s). This lock contention avoidance mechanism is similar to the one used in show_smaps_rollup(). Signed-off-by: Song Liu <songliubraving@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/bpf/20210212183107.50963-2-songliubraving@fb.com
2021-02-12Merge tag 'trace-v5.11-rc7-2' of ↵Linus Torvalds1-1/+1
git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace Pull tracing fix from Steven Rostedt: "Fix buffer overflow in trace event filter. It was reported that if an trace event was larger than a page and was filtered, that it caused memory corruption. The reason is that filtered events first go into a buffer to test the filter before being written into the ring buffer. Unfortunately, this write did not check the size" * tag 'trace-v5.11-rc7-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: tracing: Check length before giving out the filter buffer