diff options
| -rw-r--r-- | Documentation/accounting/psi.rst | 4 | ||||
| -rw-r--r-- | drivers/vhost/vhost.c | 3 | ||||
| -rw-r--r-- | include/linux/livepatch.h | 1 | ||||
| -rw-r--r-- | include/linux/livepatch_sched.h | 29 | ||||
| -rw-r--r-- | include/linux/mm_types.h | 82 | ||||
| -rw-r--r-- | include/linux/psi.h | 2 | ||||
| -rw-r--r-- | include/linux/psi_types.h | 43 | ||||
| -rw-r--r-- | include/linux/sched.h | 23 | ||||
| -rw-r--r-- | include/linux/sched/mm.h | 5 | ||||
| -rw-r--r-- | kernel/cgroup/cgroup.c | 2 | ||||
| -rw-r--r-- | kernel/fork.c | 9 | ||||
| -rw-r--r-- | kernel/livepatch/core.c | 1 | ||||
| -rw-r--r-- | kernel/livepatch/transition.c | 122 | ||||
| -rw-r--r-- | kernel/sched/clock.c | 3 | ||||
| -rw-r--r-- | kernel/sched/core.c | 669 | ||||
| -rw-r--r-- | kernel/sched/deadline.c | 11 | ||||
| -rw-r--r-- | kernel/sched/fair.c | 22 | ||||
| -rw-r--r-- | kernel/sched/psi.c | 473 | ||||
| -rw-r--r-- | kernel/sched/rt.c | 23 | ||||
| -rw-r--r-- | kernel/sched/sched.h | 243 | ||||
| -rw-r--r-- | kernel/sched/topology.c | 4 |
21 files changed, 1424 insertions, 350 deletions
diff --git a/Documentation/accounting/psi.rst b/Documentation/accounting/psi.rst index 5e40b3f437f9..df6062eb3abb 100644 --- a/Documentation/accounting/psi.rst +++ b/Documentation/accounting/psi.rst @@ -105,6 +105,10 @@ prevent overly frequent polling. Max limit is chosen as a high enough number after which monitors are most likely not needed and psi averages can be used instead. +Unprivileged users can also create monitors, with the only limitation that the +window size must be a multiple of 2s, in order to prevent excessive resource +usage. + When activated, psi monitor stays active for at least the duration of one tracking window to avoid repeated activations/deactivations when system is bouncing in and out of the stall state. diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c index 10bf35a3db6e..a92af08e7864 100644 --- a/drivers/vhost/vhost.c +++ b/drivers/vhost/vhost.c @@ -361,8 +361,7 @@ static int vhost_worker(void *data) kcov_remote_start_common(worker->kcov_handle); work->fn(work); kcov_remote_stop(); - if (need_resched()) - schedule(); + cond_resched(); } } diff --git a/include/linux/livepatch.h b/include/linux/livepatch.h index 293e29960c6e..9b9b38e89563 100644 --- a/include/linux/livepatch.h +++ b/include/linux/livepatch.h @@ -13,6 +13,7 @@ #include <linux/ftrace.h> #include <linux/completion.h> #include <linux/list.h> +#include <linux/livepatch_sched.h> #if IS_ENABLED(CONFIG_LIVEPATCH) diff --git a/include/linux/livepatch_sched.h b/include/linux/livepatch_sched.h new file mode 100644 index 000000000000..013794fb5da0 --- /dev/null +++ b/include/linux/livepatch_sched.h @@ -0,0 +1,29 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +#ifndef _LINUX_LIVEPATCH_SCHED_H_ +#define _LINUX_LIVEPATCH_SCHED_H_ + +#include <linux/jump_label.h> +#include <linux/static_call_types.h> + +#ifdef CONFIG_LIVEPATCH + +void __klp_sched_try_switch(void); + +#if !defined(CONFIG_PREEMPT_DYNAMIC) || !defined(CONFIG_HAVE_PREEMPT_DYNAMIC_CALL) + +DECLARE_STATIC_KEY_FALSE(klp_sched_try_switch_key); + +static __always_inline void klp_sched_try_switch(void) +{ + if (static_branch_unlikely(&klp_sched_try_switch_key)) + __klp_sched_try_switch(); +} + +#endif /* !CONFIG_PREEMPT_DYNAMIC || !CONFIG_HAVE_PREEMPT_DYNAMIC_CALL */ + +#else /* !CONFIG_LIVEPATCH */ +static inline void klp_sched_try_switch(void) {} +static inline void __klp_sched_try_switch(void) {} +#endif /* CONFIG_LIVEPATCH */ + +#endif /* _LINUX_LIVEPATCH_SCHED_H_ */ diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index 3fc9e680f174..306a3d1a0fa6 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -573,6 +573,13 @@ struct vm_area_struct { struct vm_userfaultfd_ctx vm_userfaultfd_ctx; } __randomize_layout; +#ifdef CONFIG_SCHED_MM_CID +struct mm_cid { + u64 time; + int cid; +}; +#endif + struct kioctx_table; struct mm_struct { struct { @@ -623,15 +630,19 @@ struct mm_struct { atomic_t mm_count; #ifdef CONFIG_SCHED_MM_CID /** - * @cid_lock: Protect cid bitmap updates vs lookups. + * @pcpu_cid: Per-cpu current cid. * - * Prevent situations where updates to the cid bitmap happen - * concurrently with lookups. Those can lead to situations - * where a lookup cannot find a free bit simply because it was - * unlucky enough to load, non-atomically, bitmap words as they - * were being concurrently updated by the updaters. + * Keep track of the currently allocated mm_cid for each cpu. + * The per-cpu mm_cid values are serialized by their respective + * runqueue locks. */ - raw_spinlock_t cid_lock; + struct mm_cid __percpu *pcpu_cid; + /* + * @mm_cid_next_scan: Next mm_cid scan (in jiffies). + * + * When the next mm_cid scan is due (in jiffies). + */ + unsigned long mm_cid_next_scan; #endif #ifdef CONFIG_MMU atomic_long_t pgtables_bytes; /* size of all page tables */ @@ -899,6 +910,37 @@ static inline void vma_iter_init(struct vma_iterator *vmi, } #ifdef CONFIG_SCHED_MM_CID + +enum mm_cid_state { + MM_CID_UNSET = -1U, /* Unset state has lazy_put flag set. */ + MM_CID_LAZY_PUT = (1U << 31), +}; + +static inline bool mm_cid_is_unset(int cid) +{ + return cid == MM_CID_UNSET; +} + +static inline bool mm_cid_is_lazy_put(int cid) +{ + return !mm_cid_is_unset(cid) && (cid & MM_CID_LAZY_PUT); +} + +static inline bool mm_cid_is_valid(int cid) +{ + return !(cid & MM_CID_LAZY_PUT); +} + +static inline int mm_cid_set_lazy_put(int cid) +{ + return cid | MM_CID_LAZY_PUT; +} + +static inline int mm_cid_clear_lazy_put(int cid) +{ + return cid & ~MM_CID_LAZY_PUT; +} + /* Accessor for struct mm_struct's cidmask. */ static inline cpumask_t *mm_cidmask(struct mm_struct *mm) { @@ -912,16 +954,40 @@ static inline cpumask_t *mm_cidmask(struct mm_struct *mm) static inline void mm_init_cid(struct mm_struct *mm) { - raw_spin_lock_init(&mm->cid_lock); + int i; + + for_each_possible_cpu(i) { + struct mm_cid *pcpu_cid = per_cpu_ptr(mm->pcpu_cid, i); + + pcpu_cid->cid = MM_CID_UNSET; + pcpu_cid->time = 0; + } cpumask_clear(mm_cidmask(mm)); } +static inline int mm_alloc_cid(struct mm_struct *mm) +{ + mm->pcpu_cid = alloc_percpu(struct mm_cid); + if (!mm->pcpu_cid) + return -ENOMEM; + mm_init_cid(mm); + return 0; +} + +static inline void mm_destroy_cid(struct mm_struct *mm) +{ + free_percpu(mm->pcpu_cid); + mm->pcpu_cid = NULL; +} + static inline unsigned int mm_cid_size(void) { return cpumask_size(); } #else /* CONFIG_SCHED_MM_CID */ static inline void mm_init_cid(struct mm_struct *mm) { } +static inline int mm_alloc_cid(struct mm_struct *mm) { return 0; } +static inline void mm_destroy_cid(struct mm_struct *mm) { } static inline unsigned int mm_cid_size(void) { return 0; diff --git a/include/linux/psi.h b/include/linux/psi.h index b029a847def1..ab26200c2803 100644 --- a/include/linux/psi.h +++ b/include/linux/psi.h @@ -24,7 +24,7 @@ void psi_memstall_leave(unsigned long *flags); int psi_show(struct seq_file *s, struct psi_group *group, enum psi_res res); struct psi_trigger *psi_trigger_create(struct psi_group *group, - char *buf, enum psi_res res); + char *buf, enum psi_res res, struct file *file); void psi_trigger_destroy(struct psi_trigger *t); __poll_t psi_trigger_poll(void **trigger_ptr, struct file *file, diff --git a/include/linux/psi_types.h b/include/linux/psi_types.h index 1e0a0d7ace3a..040c089581c6 100644 --- a/include/linux/psi_types.h +++ b/include/linux/psi_types.h @@ -151,6 +151,9 @@ struct psi_trigger { /* Deferred event(s) from previous ratelimit window */ bool pending_event; + + /* Trigger type - PSI_AVGS for unprivileged, PSI_POLL for RT */ + enum psi_aggregators aggregator; }; struct psi_group { @@ -171,30 +174,34 @@ struct psi_group { /* Aggregator work control */ struct delayed_work avgs_work; + /* Unprivileged triggers against N*PSI_FREQ windows */ + struct list_head avg_triggers; + u32 avg_nr_triggers[NR_PSI_STATES - 1]; + /* Total stall times and sampled pressure averages */ u64 total[NR_PSI_AGGREGATORS][NR_PSI_STATES - 1]; unsigned long avg[NR_PSI_STATES - 1][3]; - /* Monitor work control */ - struct task_struct __rcu *poll_task; - struct timer_list poll_timer; - wait_queue_head_t poll_wait; - atomic_t poll_wakeup; - atomic_t poll_scheduled; + /* Monitor RT polling work control */ + struct task_struct __rcu *rtpoll_task; + struct timer_list rtpoll_timer; + wait_queue_head_t rtpoll_wait; + atomic_t rtpoll_wakeup; + atomic_t rtpoll_scheduled; /* Protects data used by the monitor */ - struct mutex trigger_lock; - - /* Configured polling triggers */ - struct list_head triggers; - u32 nr_triggers[NR_PSI_STATES - 1]; - u32 poll_states; - u64 poll_min_period; - - /* Total stall times at the start of monitor activation */ - u64 polling_total[NR_PSI_STATES - 1]; - u64 polling_next_update; - u64 polling_until; + struct mutex rtpoll_trigger_lock; + + /* Configured RT polling triggers */ + struct list_head rtpoll_triggers; + u32 rtpoll_nr_triggers[NR_PSI_STATES - 1]; + u32 rtpoll_states; + u64 rtpoll_min_period; + + /* Total stall times at the start of RT polling monitor activation */ + u64 rtpoll_total[NR_PSI_STATES - 1]; + u64 rtpoll_next_update; + u64 rtpoll_until; }; #else /* CONFIG_PSI */ diff --git a/include/linux/sched.h b/include/linux/sched.h index 3f5395ae86bc..dc4ad4c58fae 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -36,6 +36,7 @@ #include <linux/seqlock.h> #include <linux/kcsan.h> #include <linux/rv.h> +#include <linux/livepatch_sched.h> #include <asm/kmap_size.h> /* task_struct member predeclarations (sorted alphabetically): */ @@ -1313,7 +1314,10 @@ struct task_struct { #ifdef CONFIG_SCHED_MM_CID int mm_cid; /* Current cid in mm */ + int last_mm_cid; /* Most recent cid in mm */ + int migrate_from_cpu; int mm_cid_active; /* Whether cid bitmap is active */ + struct callback_head cid_work; #endif struct tlbflush_unmap_batch tlb_ubc; @@ -2067,6 +2071,9 @@ extern int __cond_resched(void); #if defined(CONFIG_PREEMPT_DYNAMIC) && defined(CONFIG_HAVE_PREEMPT_DYNAMIC_CALL) +void sched_dynamic_klp_enable(void); +void sched_dynamic_klp_disable(void); + DECLARE_STATIC_CALL(cond_resched, __cond_resched); static __always_inline int _cond_resched(void) @@ -2075,6 +2082,7 @@ static __always_inline int _cond_resched(void) } #elif defined(CONFIG_PREEMPT_DYNAMIC) && defined(CONFIG_HAVE_PREEMPT_DYNAMIC_KEY) + extern int dynamic_cond_resched(void); static __always_inline int _cond_resched(void) @@ -2082,20 +2090,25 @@ static __always_inline int _cond_resched(void) return dynamic_cond_resched(); } -#else +#else /* !CONFIG_PREEMPTION */ static inline int _cond_resched(void) { + klp_sched_try_switch(); return __cond_resched(); } -#endif /* CONFIG_PREEMPT_DYNAMIC */ +#endif /* PREEMPT_DYNAMIC && CONFIG_HAVE_PREEMPT_DYNAMIC_CALL */ -#else +#else /* CONFIG_PREEMPTION && !CONFIG_PREEMPT_DYNAMIC */ -static inline int _cond_resched(void) { return 0; } +static inline int _cond_resched(void) +{ + klp_sched_try_switch(); + return 0; +} -#endif /* !defined(CONFIG_PREEMPTION) || defined(CONFIG_PREEMPT_DYNAMIC) */ +#endif /* !CONFIG_PREEMPTION || CONFIG_PREEMPT_DYNAMIC */ #define cond_resched() ({ \ __might_resched(__FILE__, __LINE__, 0); \ diff --git a/include/linux/sched/mm.h b/include/linux/sched/mm.h index af12fcb11005..b114fbe3a93b 100644 --- a/include/linux/sched/mm.h +++ b/include/linux/sched/mm.h @@ -37,6 +37,11 @@ static inline void mmgrab(struct mm_struct *mm) atomic_inc(&mm->mm_count); } +static inline void smp_mb__after_mmgrab(void) +{ + smp_mb__after_atomic(); +} + extern void __mmdrop(struct mm_struct *mm); static inline void mmdrop(struct mm_struct *mm) diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index ae518166d70a..f2a77b1b45a2 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -3771,7 +3771,7 @@ static ssize_t pressure_write(struct kernfs_open_file *of, char *buf, } psi = cgroup_psi(cgrp); - new = psi_trigger_create(psi, buf, res); + new = psi_trigger_create(psi, buf, res, of->file); if (IS_ERR(new)) { cgroup_put(cgrp); return PTR_ERR(new); diff --git a/kernel/fork.c b/kernel/fork.c index 4342200d5e2b..eccb35a85216 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -924,6 +924,7 @@ void __mmdrop(struct mm_struct *mm) check_mm(mm); put_user_ns(mm->user_ns); mm_pasid_drop(mm); + mm_destroy_cid(mm); for (i = 0; i < NR_MM_COUNTERS; i++) percpu_counter_destroy(&mm->rss_stat[i]); @@ -1188,7 +1189,9 @@ static struct task_struct *dup_task_struct(struct task_struct *orig, int node) #ifdef CONFIG_SCHED_MM_CID tsk->mm_cid = -1; + tsk->last_mm_cid = -1; tsk->mm_cid_active = 0; + tsk->migrate_from_cpu = -1; #endif return tsk; @@ -1296,18 +1299,22 @@ static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p, if (init_new_context(p, mm)) goto fail_nocontext; + if (mm_alloc_cid(mm)) + goto fail_cid; + for (i = 0; i < NR_MM_COUNTERS; i++) if (percpu_counter_init(&mm->rss_stat[i], 0, GFP_KERNEL_ACCOUNT)) goto fail_pcpu; mm->user_ns = get_user_ns(user_ns); lru_gen_init_mm(mm); - mm_init_cid(mm); return mm; fail_pcpu: while (i > 0) percpu_counter_destroy(&mm->rss_stat[--i]); + mm_destroy_cid(mm); +fail_cid: destroy_context(mm); fail_nocontext: mm_free_pgd(mm); diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c index fc851455740c..61328328c474 100644 --- a/kernel/livepatch/core.c +++ b/kernel/livepatch/core.c @@ -33,6 +33,7 @@ * * - klp_ftrace_handler() * - klp_update_patch_state() + * - __klp_sched_try_switch() */ DEFINE_MUTEX(klp_mutex); diff --git a/kernel/livepatch/transition.c b/kernel/livepatch/transition.c index f1b25ec581e0..e9fd83a02228 100644 --- a/kernel/livepatch/transition.c +++ b/kernel/livepatch/transition.c @@ -9,11 +9,14 @@ #include <linux/cpu.h> #include <linux/stacktrace.h> +#include <linux/static_call.h> #include "core.h" #include "patch.h" #include "transition.h" #define MAX_STACK_ENTRIES 100 +DEFINE_PER_CPU(unsigned long[MAX_STACK_ENTRIES], klp_stack_entries); + #define STACK_ERR_BUF_SIZE 128 #define SIGNALS_TIMEOUT 15 @@ -25,6 +28,25 @@ static int klp_target_state = KLP_UNDEFINED; static unsigned int klp_signals_cnt; /* + * When a livepatch is in progress, enable klp stack checking in + * cond_resched(). This helps CPU-bound kthreads get patched. + */ +#if defined(CONFIG_PREEMPT_DYNAMIC) && defined(CONFIG_HAVE_PREEMPT_DYNAMIC_CALL) + +#define klp_cond_resched_enable() sched_dynamic_klp_enable() +#define klp_cond_resched_disable() sched_dynamic_klp_disable() + +#else /* !CONFIG_PREEMPT_DYNAMIC || !CONFIG_HAVE_PREEMPT_DYNAMIC_CALL */ + +DEFINE_STATIC_KEY_FALSE(klp_sched_try_switch_key); +EXPORT_SYMBOL(klp_sched_try_switch_key); + +#define klp_cond_resched_enable() static_branch_enable(&klp_sched_try_switch_key) +#define klp_cond_resched_disable() static_branch_disable(&klp_sched_try_switch_key) + +#endif /* CONFIG_PREEMPT_DYNAMIC && CONFIG_HAVE_PREEMPT_DYNAMIC_CALL */ + +/* * This work can be performed periodically to finish patching or unpatching any * "straggler" tasks which failed to transition in the first attempt. */ @@ -172,8 +194,8 @@ void klp_update_patch_state(struct task_struct *task) * barrier (smp_rmb) for two cases: * * 1) Enforce the order of the TIF_PATCH_PENDING read and the - * klp_target_state read. The corresponding write barrier is in - * klp_init_transition(). + * klp_target_state read. The corresponding write barriers are in + * klp_init_transition() and klp_reverse_transition(). * * 2) Enforce the order of the TIF_PATCH_PENDING read and a future read * of func->transition, if klp_ftrace_handler() is called later on @@ -240,12 +262,15 @@ static int klp_check_stack_func(struct klp_func *func, unsigned long *entries, */ static int klp_check_stack(struct task_struct *task, const char **oldname) { - static unsigned long entries[MAX_STACK_ENTRIES]; + unsigned long *entries = this_cpu_ptr(klp_stack_entries); struct klp_object *obj; struct klp_func *func; int ret, nr_entries; - ret = stack_trace_save_tsk_reliable(task, entries, ARRAY_SIZE(entries)); + /* Protect 'klp_stack_entries' */ + lockdep_assert_preemption_disabled(); + + ret = stack_trace_save_tsk_reliable(task, entries, MAX_STACK_ENTRIES); if (ret < 0) return -EINVAL; nr_entries = ret; @@ -307,7 +332,11 @@ static bool klp_try_switch_task(struct task_struct *task) * functions. If all goes well, switch the task to the target patch * state. */ - ret = task_call_func(task, klp_check_and_switch_task, &old_name); + if (task == current) + ret = klp_check_and_switch_task(current, &old_name); + else + ret = task_call_func(task, klp_check_and_switch_task, &old_name); + switch (ret) { case 0: /* success */ break; @@ -334,6 +363,44 @@ static bool klp_try_switch_task(struct task_struct *task) return !ret; } +void __klp_sched_try_switch(void) +{ + if (likely(!klp_patch_pending(current))) + return; + + /* + * This function is called from cond_resched() which is called in many + * places throughout the kernel. Using the klp_mutex here might + * deadlock. + * + * Instead, disable preemption to prevent racing with other callers of + * klp_try_switch_task(). Thanks to task_call_func() they won't be + * able to switch this task while it's running. + */ + preempt_disable(); + + /* + * Make sure current didn't get patched between the above check and + * preempt_disable(). + */ + if (unlikely(!klp_patch_pending(current))) + goto out; + + /* + * Enforce the order of the TIF_PATCH_PENDING read above and the + * klp_target_state read in klp_try_switch_task(). The corresponding + * write barriers are in klp_init_transition() and + * klp_reverse_transition(). + */ + smp_rmb(); + + klp_try_switch_task(current); + +out: + preempt_enable(); +} +EXPORT_SYMBOL(__klp_sched_try_switch); + /* * Sends a fake signal to all non-kthread tasks with TIF_PATCH_PENDING set. * Kthreads with TIF_PATCH_PENDING set are woken up. @@ -440,7 +507,8 @@ void klp_try_complete_transition(void) return; } - /* we're done, now cleanup the data structures */ + /* Done! Now cleanup the data structures. */ + klp_cond_resched_disable(); patch = klp_transition_patch; klp_complete_transition(); @@ -492,6 +560,8 @@ void klp_start_transition(void) set_tsk_thread_flag(task, TIF_PATCH_PENDING); } + klp_cond_resched_enable(); + klp_signals_cnt = 0; } @@ -547,8 +617,9 @@ void klp_init_transition(struct klp_patch *patch, int state) * see a func in transition with a task->patch_state of KLP_UNDEFINED. * * Also enforce the order of the klp_target_state write and future - * TIF_PATCH_PENDING writes to ensure klp_update_patch_state() doesn't - * set a task->patch_state to KLP_UNDEFINED. + * TIF_PATCH_PENDING writes to ensure klp_update_patch_state() and + * __klp_sched_try_switch() don't set a task->patch_state to + * KLP_UNDEFINED. */ smp_wmb(); @@ -584,14 +655,10 @@ void klp_reverse_transition(void) klp_target_state == KLP_PATCHED ? "patching to unpatching" : "unpatching to patching"); - klp_transition_patch->enabled = !klp_transition_patch->enabled; - - klp_target_state = !klp_target_state; - /* * Clear all TIF_PATCH_PENDING flags to prevent races caused by - * klp_update_patch_state() running in parallel with - * klp_start_transition(). + * klp_update_patch_state() or __klp_sched_try_switch() running in + * parallel with the reverse transition. */ read_lock(&tasklist_lock); for_each_process_thread(g, task) @@ -601,9 +668,28 @@ void klp_reverse_transition(void) for_each_possible_cpu(cpu) clear_tsk_thread_flag(idle_task(cpu), TIF_PATCH_PENDING); - /* Let any remaining calls to klp_update_patch_state() complete */ + /* + * Make sure all existing invocations of klp_update_patch_state() and + * __klp_sched_try_switch() see the cleared TIF_PATCH_PENDING before + * starting the reverse transition. + */ klp_synchronize_transition(); + /* + * All patching has stopped, now re-initialize the global variables to + * prepare for the reverse transition. + */ + klp_transition_patch->enabled = !klp_transition_patch->enabled; + klp_target_state = !klp_target_state; + + /* + * Enforce the order of the klp_target_state write and the + * TIF_PATCH_PENDING writes in klp_start_transition() to ensure + * klp_update_patch_state() and __klp_sched_try_switch() don't set + * task->patch_state to the wrong value. + */ + smp_wmb(); + klp_start_transition(); } @@ -617,9 +703,9 @@ void klp_copy_process(struct task_struct *child) * the task flag up to date with the parent here. * * The operation is serialized against all klp_*_transition() - * operations by the tasklist_lock. The only exception is - * klp_update_patch_state(current), but we cannot race with - * that because we are current. + * operations by the tasklist_lock. The only exceptions are + * klp_update_patch_state(current) and __klp_sched_try_switch(), but we + * cannot race with them because we are current. */ if (test_tsk_thread_flag(current, TIF_PATCH_PENDING)) set_tsk_thread_flag(child, TIF_PATCH_PENDING); diff --git a/kernel/sched/clock.c b/kernel/sched/clock.c index 5732fa75ebab..b5cc2b53464d 100644 --- a/kernel/sched/clock.c +++ b/kernel/sched/clock.c @@ -300,6 +300,9 @@ noinstr u64 local_clock(void) if (static_branch_likely(&__sched_clock_stable)) return sched_clock() + __sched_clock_offset; + if (!static_branch_likely(&sched_clock_running)) + return sched_clock(); + preempt_disable_notrace(); clock = sched_clock_local(this_scd()); preempt_enable_notrace(); diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 8d2b6742d02c..54c75af24899 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -261,36 +261,51 @@ void sched_core_dequeue(struct rq *rq, struct task_struct *p, int flags) resched_curr(rq); } -/* - * Find left-most (aka, highest priority) task matching @cookie. - */ -static struct task_struct *sched_core_find(struct rq *rq, unsigned long cookie) +static int sched_task_is_throttled(struct task_struct *p, int cpu) { - struct rb_node *node; - - node = rb_find_first((void *)cookie, &rq->core_tree, rb_sched_core_cmp); - /* - * The idle task always matches any cookie! - */ - if (!node) - return idle_sched_class.pick_task(rq); + if (p->sched_class->task_is_throttled) + return p->sched_class->task_is_throttled(p, cpu); - return __node_2_sc(node); + return 0; } static struct task_struct *sched_core_next(struct task_struct *p, unsigned long cookie) { struct rb_node *node = &p->core_node; + int cpu = task_cpu(p); - node = rb_next(node); + do { + node = rb_next(node); + if (!node) + return NULL; + + p = __node_2_sc(node); + if (p->core_cookie != cookie) + return NULL; + + } while (sched_task_is_throttled(p, cpu)); + + return p; +} + +/* + * Find left-most (aka, highest priority) and unthrottled task matching @cookie. + * If no suitable task is found, NULL will be returned. + */ +static struct task_struct *sched_core_find(struct rq *rq, unsigned long cookie) +{ + struct task_struct *p; + struct rb_node *node; + + node = rb_find_first((void *)cookie, &rq->core_tree, rb_sched_core_cmp); if (!node) return NULL; - p = container_of(node, struct task_struct, core_node); - if (p->core_cookie != cookie) - return NULL; + p = __node_2_sc(node); + if (!sched_task_is_throttled(p, rq->cpu)) + return p; - return p; + return sched_core_next(p, cookie); } /* @@ -2087,6 +2102,8 @@ void activate_task(struct rq *rq, struct task_struct *p, int flags) { if (task_on_rq_migrating(p)) flags |= ENQUEUE_MIGRATED; + if (flags & ENQUEUE_MIGRATED) + sched_mm_cid_migrate_to(rq, p); enqueue_task(rq, p, flags); @@ -3196,6 +3213,7 @@ void set_task_cpu(struct task_struct *p, unsigned int new_cpu) p->sched_class->migrate_task_rq(p, new_cpu); p->se.nr_migrations++; rseq_migrate(p); + sched_mm_cid_migrate_from(p); perf_event_task_migrate(p); } @@ -4469,6 +4487,7 @@ static void __sched_fork(unsigned long clone_flags, struct task_struct *p) p->wake_entry.u_flags = CSD_TYPE_TTWU; p->migration_pending = NULL; #endif + init_sched_mm_cid(p); } DEFINE_STATIC_KEY_FALSE(sched_numa_balancing); @@ -5115,7 +5134,6 @@ prepare_task_switch(struct rq *rq, struct task_struct *prev, sched_info_switch(rq, prev, next); perf_event_task_sched_out(prev, next); rseq_preempt(prev); - switch_mm_cid(prev, next); fire_sched_out_preempt_notifiers(prev, next); kmap_local_sched_out(); prepare_task(next); @@ -5272,6 +5290,9 @@ context_switch(struct rq *rq, struct task_struct *prev, * * kernel -> user switch + mmdrop_lazy_tlb() active * user -> user switch + * + * switch_mm_cid() needs to be updated if the barriers provided + * by context_switch() are modified. */ if (!next->mm) { // to kernel enter_lazy_tlb(prev->active_mm, next); @@ -5301,6 +5322,9 @@ context_switch(struct rq *rq, struct task_struct *prev, } } + /* switch_mm_cid() requires the memory barriers above. */ + switch_mm_cid(rq, prev, next); + rq->clock_update_flags &= ~(RQCF_ACT_SKIP|RQCF_REQ_SKIP); prepare_lock_switch(rq, next, rf); @@ -5589,6 +5613,7 @@ void scheduler_tick(void) resched_latency = cpu_resched_latency(rq); calc_global_load_tick(rq); sched_core_tick(rq); + task_tick_mm_cid(rq, curr); rq_unlock(rq, &rf); @@ -6241,7 +6266,7 @@ static bool try_steal_cookie(int this, int that) goto unlock; p = sched_core_find(src, cookie); - if (p == src->idle) + if (!p) goto unlock; do { @@ -6253,6 +6278,13 @@ static bool try_steal_cookie(int this, int that) if (p->core_occupation > dst->idle->core_occupation) goto next; + /* + * sched_core_find() and sched_core_next() will ensure that task @p + * is not throttled now, we also need to check whether the runqueue + * of the destination CPU is being throttled. + */ + if (sched_task_is_throttled(p, this)) + goto next; deactivate_task(src, p, 0); set_task_cpu(p, this); @@ -8508,6 +8540,7 @@ EXPORT_STATIC_CALL_TRAMP(might_resched); static DEFINE_STATIC_KEY_FALSE(sk_dynamic_cond_resched); int __sched dynamic_cond_resched(void) { + klp_sched_try_switch(); if (!static_branch_unlikely(&sk_dynamic_cond_resched)) return 0; return __cond_resched(); @@ -8656,13 +8689,17 @@ int sched_dynamic_mode(const char *str) #error "Unsupported PREEMPT_DYNAMIC mechanism" #endif -void sched_dynamic_update(int mode) +static DEFINE_MUTEX(sched_dynamic_mutex); +static bool klp_override; + +static void __sched_dynamic_update(int mode) { /* * Avoid {NONE,VOLUNTARY} -> FULL transitions from ever ending up in * the ZERO state, which is invalid. */ - preempt_dynamic_enable(cond_resched); + if (!klp_override) + preempt_dynamic_enable(cond_resched); preempt_dynamic_enable(might_resched); preempt_dynamic_enable(preempt_schedule); preempt_dynamic_enable(preempt_schedule_notrace); @@ -8670,36 +8707,79 @@ void sched_dynamic_update(int mode) switch (mode) { case preempt_dynamic_none: - preempt_dynamic_enable(cond_resched); + if (!klp_override) + preempt_dynamic_enable(cond_resched); preempt_dynamic_disable(might_resched); preempt_dynamic_disable(preempt_schedule); preempt_dynamic_disable(preempt_schedule_notrace); preempt_dynamic_disable(irqentry_exit_cond_resched); - pr_info("Dynamic Preempt: none\n"); + if (mode != preempt_dynamic_mode) + pr_info("Dynamic Preempt: none\n"); break; case preempt_dynamic_voluntary: - preempt_dynamic_enable(cond_resched); + if (!klp_override) + preempt_dynamic_enable(cond_resched); preempt_dynamic_enable(might_resched); preempt_dynamic_disable(preempt_schedule); preempt_dynamic_disable(preempt_schedule_notrace); preempt_dynamic_disable(irqentry_exit_cond_resched); - pr_info("Dynamic Preempt: voluntary\n"); + if (mode != preempt_dynamic_mode) + pr_info("Dynamic Preempt: voluntary\n"); break; case preempt_dynamic_full: - preempt_dynamic_disable(cond_resched); + if (!klp_override) + preempt_dynamic_disable(cond_resched); preempt_dynamic_disable(might_resched); preempt_dynamic_enable(preempt_schedule); preempt_dynamic_enable(preempt_schedule_notrace); preempt_dynamic_enable(irqentry_exit_cond_resched); - pr_info("Dynamic Preempt: full\n"); + if (mode != preempt_dynamic_mode) + pr_info("Dynamic Preempt: full\n"); break; } preempt_dynamic_mode = mode; } +void sched_dynamic_update(int mode) +{ + mutex_lock(&sched_dynamic_mutex); + __sched_dynamic_update(mode); + mutex_unlock(&sched_dynamic_mutex); +} + +#ifdef CONFIG_HAVE_PREEMPT_DYNAMIC_CALL + +static int klp_cond_resched(void) +{ + __klp_sched_try_switch(); + return __cond_resched(); +} + +void sched_dynamic_klp_enable(void) +{ + mutex_lock(&sched_dynamic_mutex); + + klp_override = true; + static_call_update(cond_resched, klp_cond_resched); + + mutex_unlock(&sched_dynamic_mutex); +} + +void sched_dynamic_klp_disable(void) +{ + mutex_lock(&sched_dynamic_mutex); + + klp_override = false; + __sched_dynamic_upda |