diff options
author | Ingo Molnar <mingo@kernel.org> | 2024-10-17 09:58:07 +0200 |
---|---|---|
committer | Ingo Molnar <mingo@kernel.org> | 2024-10-17 09:58:07 +0200 |
commit | be602cde657ee43d23adbf309be6d700d0106dc9 (patch) | |
tree | d27775738d0deefe7c3071be7d667912dc3ee932 /kernel | |
parent | cd9626e9ebc77edec33023fe95dab4b04ffc819d (diff) | |
parent | c964ced7726294d40913f2127c3f185a92cb4a41 (diff) |
Merge branch 'linus' into sched/urgent, to resolve conflict
Conflicts:
kernel/sched/ext.c
There's a context conflict between this upstream commit:
3fdb9ebcec10 sched_ext: Start schedulers with consistent p->scx.slice values
... and this fix in sched/urgent:
98442f0ccd82 sched: Fix delayed_dequeue vs switched_from_fair()
Resolve it.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel')
-rw-r--r-- | kernel/bpf/core.c | 2 | ||||
-rw-r--r-- | kernel/debug/gdbstub.c | 2 | ||||
-rw-r--r-- | kernel/fork.c | 32 | ||||
-rw-r--r-- | kernel/kthread.c | 2 | ||||
-rw-r--r-- | kernel/rcu/tree.c | 9 | ||||
-rw-r--r-- | kernel/rcu/tree_nocb.h | 8 | ||||
-rw-r--r-- | kernel/resource_kunit.c | 18 | ||||
-rw-r--r-- | kernel/sched/core.c | 21 | ||||
-rw-r--r-- | kernel/sched/ext.c | 218 | ||||
-rw-r--r-- | kernel/sched/psi.c | 26 | ||||
-rw-r--r-- | kernel/sched/sched.h | 3 | ||||
-rw-r--r-- | kernel/trace/ring_buffer.c | 53 | ||||
-rw-r--r-- | kernel/trace/trace.c | 21 | ||||
-rw-r--r-- | kernel/trace/trace_hwlat.c | 2 | ||||
-rw-r--r-- | kernel/trace/trace_osnoise.c | 22 |
15 files changed, 257 insertions, 182 deletions
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index 4e07cc057d6f..5e77c58e0601 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -40,7 +40,7 @@ #include <linux/execmem.h> #include <asm/barrier.h> -#include <asm/unaligned.h> +#include <linux/unaligned.h> /* Registers */ #define BPF_R0 regs[BPF_REG_0] diff --git a/kernel/debug/gdbstub.c b/kernel/debug/gdbstub.c index 9d34d2364b5a..f625172d4b67 100644 --- a/kernel/debug/gdbstub.c +++ b/kernel/debug/gdbstub.c @@ -33,7 +33,7 @@ #include <linux/reboot.h> #include <linux/uaccess.h> #include <asm/cacheflush.h> -#include <asm/unaligned.h> +#include <linux/unaligned.h> #include "debug_core.h" #define KGDB_MAX_THREAD_QUERY 17 diff --git a/kernel/fork.c b/kernel/fork.c index 60c0b4868fd4..89ceb4a68af2 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -1756,33 +1756,30 @@ static int copy_files(unsigned long clone_flags, struct task_struct *tsk, int no_files) { struct files_struct *oldf, *newf; - int error = 0; /* * A background process may not have any files ... */ oldf = current->files; if (!oldf) - goto out; + return 0; if (no_files) { tsk->files = NULL; - goto out; + return 0; } if (clone_flags & CLONE_FILES) { atomic_inc(&oldf->count); - goto out; + return 0; } - newf = dup_fd(oldf, NR_OPEN_MAX, &error); - if (!newf) - goto out; + newf = dup_fd(oldf, NULL); + if (IS_ERR(newf)) + return PTR_ERR(newf); tsk->files = newf; - error = 0; -out: - return error; + return 0; } static int copy_sighand(unsigned long clone_flags, struct task_struct *tsk) @@ -3238,17 +3235,16 @@ static int unshare_fs(unsigned long unshare_flags, struct fs_struct **new_fsp) /* * Unshare file descriptor table if it is being shared */ -int unshare_fd(unsigned long unshare_flags, unsigned int max_fds, - struct files_struct **new_fdp) +static int unshare_fd(unsigned long unshare_flags, struct files_struct **new_fdp) { struct files_struct *fd = current->files; - int error = 0; if ((unshare_flags & CLONE_FILES) && (fd && atomic_read(&fd->count) > 1)) { - *new_fdp = dup_fd(fd, max_fds, &error); - if (!*new_fdp) - return error; + fd = dup_fd(fd, NULL); + if (IS_ERR(fd)) + return PTR_ERR(fd); + *new_fdp = fd; } return 0; @@ -3306,7 +3302,7 @@ int ksys_unshare(unsigned long unshare_flags) err = unshare_fs(unshare_flags, &new_fs); if (err) goto bad_unshare_out; - err = unshare_fd(unshare_flags, NR_OPEN_MAX, &new_fd); + err = unshare_fd(unshare_flags, &new_fd); if (err) goto bad_unshare_cleanup_fs; err = unshare_userns(unshare_flags, &new_cred); @@ -3398,7 +3394,7 @@ int unshare_files(void) struct files_struct *old, *copy = NULL; int error; - error = unshare_fd(CLONE_FILES, NR_OPEN_MAX, ©); + error = unshare_fd(CLONE_FILES, ©); if (error || !copy) return error; diff --git a/kernel/kthread.c b/kernel/kthread.c index db4ceb0f503c..9bb36897b6c6 100644 --- a/kernel/kthread.c +++ b/kernel/kthread.c @@ -623,6 +623,8 @@ void kthread_unpark(struct task_struct *k) { struct kthread *kthread = to_kthread(k); + if (!test_bit(KTHREAD_SHOULD_PARK, &kthread->flags)) + return; /* * Newly created kthread was parked when the CPU was offline. * The binding was lost and we need to set it again. diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index a60616e69b66..b1f883fcd918 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -3607,11 +3607,12 @@ kvfree_rcu_queue_batch(struct kfree_rcu_cpu *krcp) } // One work is per one batch, so there are three - // "free channels", the batch can handle. It can - // be that the work is in the pending state when - // channels have been detached following by each - // other. + // "free channels", the batch can handle. Break + // the loop since it is done with this CPU thus + // queuing an RCU work is _always_ success here. queued = queue_rcu_work(system_unbound_wq, &krwp->rcu_work); + WARN_ON_ONCE(!queued); + break; } } diff --git a/kernel/rcu/tree_nocb.h b/kernel/rcu/tree_nocb.h index 97b99cd06923..16865475120b 100644 --- a/kernel/rcu/tree_nocb.h +++ b/kernel/rcu/tree_nocb.h @@ -554,13 +554,19 @@ static void __call_rcu_nocb_wake(struct rcu_data *rdp, bool was_alldone, rcu_nocb_unlock(rdp); wake_nocb_gp_defer(rdp, RCU_NOCB_WAKE_LAZY, TPS("WakeLazy")); - } else if (!irqs_disabled_flags(flags)) { + } else if (!irqs_disabled_flags(flags) && cpu_online(rdp->cpu)) { /* ... if queue was empty ... */ rcu_nocb_unlock(rdp); wake_nocb_gp(rdp, false); trace_rcu_nocb_wake(rcu_state.name, rdp->cpu, TPS("WakeEmpty")); } else { + /* + * Don't do the wake-up upfront on fragile paths. + * Also offline CPUs can't call swake_up_one_online() from + * (soft-)IRQs. Rely on the final deferred wake-up from + * rcutree_report_cpu_dead() + */ rcu_nocb_unlock(rdp); wake_nocb_gp_defer(rdp, RCU_NOCB_WAKE, TPS("WakeEmptyIsDeferred")); diff --git a/kernel/resource_kunit.c b/kernel/resource_kunit.c index 42d2d8d20f5d..b8ef75b99eb2 100644 --- a/kernel/resource_kunit.c +++ b/kernel/resource_kunit.c @@ -169,6 +169,8 @@ static void resource_test_intersection(struct kunit *test) #define RES_TEST_RAM3_SIZE SZ_1M #define RES_TEST_TOTAL_SIZE ((RES_TEST_WIN1_OFFSET + RES_TEST_WIN1_SIZE)) +KUNIT_DEFINE_ACTION_WRAPPER(kfree_wrapper, kfree, const void *); + static void remove_free_resource(void *ctx) { struct resource *res = (struct resource *)ctx; @@ -177,6 +179,14 @@ static void remove_free_resource(void *ctx) kfree(res); } +static void resource_test_add_action_or_abort( + struct kunit *test, void (*action)(void *), void *ctx) +{ + KUNIT_ASSERT_EQ_MSG(test, 0, + kunit_add_action_or_reset(test, action, ctx), + "Fail to add action"); +} + static void resource_test_request_region(struct kunit *test, struct resource *parent, resource_size_t start, resource_size_t size, const char *name, unsigned long flags) @@ -185,7 +195,7 @@ static void resource_test_request_region(struct kunit *test, struct resource *pa res = __request_region(parent, start, size, name, flags); KUNIT_ASSERT_NOT_NULL(test, res); - kunit_add_action_or_reset(test, remove_free_resource, res); + resource_test_add_action_or_abort(test, remove_free_resource, res); } static void resource_test_insert_resource(struct kunit *test, struct resource *parent, @@ -202,11 +212,11 @@ static void resource_test_insert_resource(struct kunit *test, struct resource *p res->end = start + size - 1; res->flags = flags; if (insert_resource(parent, res)) { - kfree(res); + resource_test_add_action_or_abort(test, kfree_wrapper, res); KUNIT_FAIL_AND_ABORT(test, "Fail to insert resource %pR\n", res); } - kunit_add_action_or_reset(test, remove_free_resource, res); + resource_test_add_action_or_abort(test, remove_free_resource, res); } static void resource_test_region_intersects(struct kunit *test) @@ -220,7 +230,7 @@ static void resource_test_region_intersects(struct kunit *test) "test resources"); KUNIT_ASSERT_NOT_ERR_OR_NULL(test, parent); start = parent->start; - kunit_add_action_or_reset(test, remove_free_resource, parent); + resource_test_add_action_or_abort(test, remove_free_resource, parent); resource_test_request_region(test, parent, start + RES_TEST_RAM0_OFFSET, RES_TEST_RAM0_SIZE, "Test System RAM 0", flags); diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 7db711ba6d12..dbfb5717d6af 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -3523,14 +3523,16 @@ out: * The caller (fork, wakeup) owns p->pi_lock, ->cpus_ptr is stable. */ static inline -int select_task_rq(struct task_struct *p, int cpu, int wake_flags) +int select_task_rq(struct task_struct *p, int cpu, int *wake_flags) { lockdep_assert_held(&p->pi_lock); - if (p->nr_cpus_allowed > 1 && !is_migration_disabled(p)) - cpu = p->sched_class->select_task_rq(p, cpu, wake_flags); - else + if (p->nr_cpus_allowed > 1 && !is_migration_disabled(p)) { + cpu = p->sched_class->select_task_rq(p, cpu, *wake_flags); + *wake_flags |= WF_RQ_SELECTED; + } else { cpu = cpumask_any(p->cpus_ptr); + } /* * In order not to call set_task_cpu() on a blocking task we need @@ -3664,6 +3666,8 @@ ttwu_do_activate(struct rq *rq, struct task_struct *p, int wake_flags, rq->nr_uninterruptible--; #ifdef CONFIG_SMP + if (wake_flags & WF_RQ_SELECTED) + en_flags |= ENQUEUE_RQ_SELECTED; if (wake_flags & WF_MIGRATED) en_flags |= ENQUEUE_MIGRATED; else @@ -4125,6 +4129,8 @@ int try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags) guard(preempt)(); int cpu, success = 0; + wake_flags |= WF_TTWU; + if (p == current) { /* * We're waking current, this means 'p->on_rq' and 'task_cpu(p) @@ -4257,7 +4263,7 @@ int try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags) */ smp_cond_load_acquire(&p->on_cpu, !VAL); - cpu = select_task_rq(p, p->wake_cpu, wake_flags | WF_TTWU); + cpu = select_task_rq(p, p->wake_cpu, &wake_flags); if (task_cpu(p) != cpu) { if (p->in_iowait) { delayacct_blkio_end(p); @@ -4799,6 +4805,7 @@ void wake_up_new_task(struct task_struct *p) { struct rq_flags rf; struct rq *rq; + int wake_flags = WF_FORK; raw_spin_lock_irqsave(&p->pi_lock, rf.flags); WRITE_ONCE(p->__state, TASK_RUNNING); @@ -4813,7 +4820,7 @@ void wake_up_new_task(struct task_struct *p) */ p->recent_used_cpu = task_cpu(p); rseq_migrate(p); - __set_task_cpu(p, select_task_rq(p, task_cpu(p), WF_FORK)); + __set_task_cpu(p, select_task_rq(p, task_cpu(p), &wake_flags)); #endif rq = __task_rq_lock(p, &rf); update_rq_clock(rq); @@ -4821,7 +4828,7 @@ void wake_up_new_task(struct task_struct *p) activate_task(rq, p, ENQUEUE_NOCLOCK | ENQUEUE_INITIAL); trace_sched_wakeup_new(p); - wakeup_preempt(rq, p, WF_FORK); + wakeup_preempt(rq, p, wake_flags); #ifdef CONFIG_SMP if (p->sched_class->task_woken) { /* diff --git a/kernel/sched/ext.c b/kernel/sched/ext.c index 6f9de573ee93..5900b06fd036 100644 --- a/kernel/sched/ext.c +++ b/kernel/sched/ext.c @@ -9,7 +9,6 @@ #define SCX_OP_IDX(op) (offsetof(struct sched_ext_ops, op) / sizeof(void (*)(void))) enum scx_consts { - SCX_SLICE_BYPASS = SCX_SLICE_DFL / 4, SCX_DSP_DFL_MAX_BATCH = 32, SCX_DSP_MAX_LOOPS = 32, SCX_WATCHDOG_MAX_TIMEOUT = 30 * HZ, @@ -19,6 +18,12 @@ enum scx_consts { SCX_EXIT_DUMP_DFL_LEN = 32768, SCX_CPUPERF_ONE = SCHED_CAPACITY_SCALE, + + /* + * Iterating all tasks may take a while. Periodically drop + * scx_tasks_lock to avoid causing e.g. CSD and RCU stalls. + */ + SCX_OPS_TASK_ITER_BATCH = 32, }; enum scx_exit_kind { @@ -625,6 +630,10 @@ struct sched_ext_ops { /** * exit - Clean up after the BPF scheduler * @info: Exit info + * + * ops.exit() is also called on ops.init() failure, which is a bit + * unusual. This is to allow rich reporting through @info on how + * ops.init() failed. */ void (*exit)(struct scx_exit_info *info); @@ -692,6 +701,7 @@ enum scx_enq_flags { /* expose select ENQUEUE_* flags as enums */ SCX_ENQ_WAKEUP = ENQUEUE_WAKEUP, SCX_ENQ_HEAD = ENQUEUE_HEAD, + SCX_ENQ_CPU_SELECTED = ENQUEUE_RQ_SELECTED, /* high 32bits are SCX specific */ @@ -1269,86 +1279,104 @@ struct scx_task_iter { struct task_struct *locked; struct rq *rq; struct rq_flags rf; + u32 cnt; }; /** - * scx_task_iter_init - Initialize a task iterator + * scx_task_iter_start - Lock scx_tasks_lock and start a task iteration * @iter: iterator to init * - * Initialize @iter. Must be called with scx_tasks_lock held. Once initialized, - * @iter must eventually be exited with scx_task_iter_exit(). + * Initialize @iter and return with scx_tasks_lock held. Once initialized, @iter + * must eventually be stopped with scx_task_iter_stop(). * - * scx_tasks_lock may be released between this and the first next() call or - * between any two next() calls. If scx_tasks_lock is released between two - * next() calls, the caller is responsible for ensuring that the task being - * iterated remains accessible either through RCU read lock or obtaining a - * reference count. + * scx_tasks_lock and the rq lock may be released using scx_task_iter_unlock() + * between this and the first next() call or between any two next() calls. If + * the locks are released between two next() calls, the caller is responsible + * for ensuring that the task being iterated remains accessible either through + * RCU read lock or obtaining a reference count. * * All tasks which existed when the iteration started are guaranteed to be * visited as long as they still exist. */ -static void scx_task_iter_init(struct scx_task_iter *iter) +static void scx_task_iter_start(struct scx_task_iter *iter) { - lockdep_assert_held(&scx_tasks_lock); - BUILD_BUG_ON(__SCX_DSQ_ITER_ALL_FLAGS & ((1U << __SCX_DSQ_LNODE_PRIV_SHIFT) - 1)); + spin_lock_irq(&scx_tasks_lock); + iter->cursor = (struct sched_ext_entity){ .flags = SCX_TASK_CURSOR }; list_add(&iter->cursor.tasks_node, &scx_tasks); iter->locked = NULL; + iter->cnt = 0; +} + +static void __scx_task_iter_rq_unlock(struct scx_task_iter *iter) +{ + if (iter->locked) { + task_rq_unlock(iter->rq, iter->locked, &iter->rf); + iter->locked = NULL; + } } /** - * scx_task_iter_rq_unlock - Unlock rq locked by a task iterator - * @iter: iterator to unlock rq for + * scx_task_iter_unlock - Unlock rq and scx_tasks_lock held by a task iterator + * @iter: iterator to unlock * * If @iter is in the middle of a locked iteration, it may be locking the rq of - * the task currently being visited. Unlock the rq if so. This function can be - * safely called anytime during an iteration. + * the task currently being visited in addition to scx_tasks_lock. Unlock both. + * This function can be safely called anytime during an iteration. + */ +static void scx_task_iter_unlock(struct scx_task_iter *iter) +{ + __scx_task_iter_rq_unlock(iter); + spin_unlock_irq(&scx_tasks_lock); +} + +/** + * scx_task_iter_relock - Lock scx_tasks_lock released by scx_task_iter_unlock() + * @iter: iterator to re-lock * - * Returns %true if the rq @iter was locking is unlocked. %false if @iter was - * not locking an rq. + * Re-lock scx_tasks_lock unlocked by scx_task_iter_unlock(). Note that it + * doesn't re-lock the rq lock. Must be called before other iterator operations. */ -static bool scx_task_iter_rq_unlock(struct scx_task_iter *iter) +static void scx_task_iter_relock(struct scx_task_iter *iter) { - if (iter->locked) { - task_rq_unlock(iter->rq, iter->locked, &iter->rf); - iter->locked = NULL; - return true; - } else { - return false; - } + spin_lock_irq(&scx_tasks_lock); } /** - * scx_task_iter_exit - Exit a task iterator + * scx_task_iter_stop - Stop a task iteration and unlock scx_tasks_lock * @iter: iterator to exit * - * Exit a previously initialized @iter. Must be called with scx_tasks_lock held. - * If the iterator holds a task's rq lock, that rq lock is released. See - * scx_task_iter_init() for details. + * Exit a previously initialized @iter. Must be called with scx_tasks_lock held + * which is released on return. If the iterator holds a task's rq lock, that rq + * lock is also released. See scx_task_iter_start() for details. */ -static void scx_task_iter_exit(struct scx_task_iter *iter) +static void scx_task_iter_stop(struct scx_task_iter *iter) { - lockdep_assert_held(&scx_tasks_lock); - - scx_task_iter_rq_unlock(iter); list_del_init(&iter->cursor.tasks_node); + scx_task_iter_unlock(iter); } /** * scx_task_iter_next - Next task * @iter: iterator to walk * - * Visit the next task. See scx_task_iter_init() for details. + * Visit the next task. See scx_task_iter_start() for details. Locks are dropped + * and re-acquired every %SCX_OPS_TASK_ITER_BATCH iterations to avoid causing + * stalls by holding scx_tasks_lock for too long. */ static struct task_struct *scx_task_iter_next(struct scx_task_iter *iter) { struct list_head *cursor = &iter->cursor.tasks_node; struct sched_ext_entity *pos; - lockdep_assert_held(&scx_tasks_lock); + if (!(++iter->cnt % SCX_OPS_TASK_ITER_BATCH)) { + scx_task_iter_unlock(iter); + cond_resched(); + scx_task_iter_relock(iter); + } list_for_each_entry(pos, cursor, tasks_node) { if (&pos->tasks_node == &scx_tasks) @@ -1369,14 +1397,14 @@ static struct task_struct *scx_task_iter_next(struct scx_task_iter *iter) * @include_dead: Whether we should include dead tasks in the iteration * * Visit the non-idle task with its rq lock held. Allows callers to specify - * whether they would like to filter out dead tasks. See scx_task_iter_init() + * whether they would like to filter out dead tasks. See scx_task_iter_start() * for details. */ static struct task_struct *scx_task_iter_next_locked(struct scx_task_iter *iter) { struct task_struct *p; - scx_task_iter_rq_unlock(iter); + __scx_task_iter_rq_unlock(iter); while ((p = scx_task_iter_next(iter))) { /* @@ -1944,7 +1972,6 @@ static bool scx_rq_online(struct rq *rq) static void do_enqueue_task(struct rq *rq, struct task_struct *p, u64 enq_flags, int sticky_cpu) { - bool bypassing = scx_rq_bypassing(rq); struct task_struct **ddsp_taskp; unsigned long qseq; @@ -1962,7 +1989,7 @@ static void do_enqueue_task(struct rq *rq, struct task_struct *p, u64 enq_flags, if (!scx_rq_online(rq)) goto local; - if (bypassing) + if (scx_rq_bypassing(rq)) goto global; if (p->scx.ddsp_dsq_id != SCX_DSQ_INVALID) @@ -2017,7 +2044,7 @@ local_norefill: global: touch_core_sched(rq, p); /* see the comment in local: */ - p->scx.slice = bypassing ? SCX_SLICE_BYPASS : SCX_SLICE_DFL; + p->scx.slice = SCX_SLICE_DFL; dispatch_enqueue(find_global_dsq(p), p, enq_flags); } @@ -2953,8 +2980,8 @@ static struct task_struct *pick_task_scx(struct rq *rq) if (unlikely(!p->scx.slice)) { if (!scx_rq_bypassing(rq) && !scx_warned_zero_slice) { - printk_deferred(KERN_WARNING "sched_ext: %s[%d] has zero slice in pick_next_task_scx()\n", - p->comm, p->pid); + printk_deferred(KERN_WARNING "sched_ext: %s[%d] has zero slice in %s()\n", + p->comm, p->pid, __func__); scx_warned_zero_slice = true; } p->scx.slice = SCX_SLICE_DFL; @@ -3059,11 +3086,6 @@ static s32 scx_select_cpu_dfl(struct task_struct *p, s32 prev_cpu, *found = false; - if (!static_branch_likely(&scx_builtin_idle_enabled)) { - scx_ops_error("built-in idle tracking is disabled"); - return prev_cpu; - } - /* * If WAKE_SYNC, the waker's local DSQ is empty, and the system is * under utilized, wake up @p to the local DSQ of the waker. Checking @@ -3128,7 +3150,7 @@ static int select_task_rq_scx(struct task_struct *p, int prev_cpu, int wake_flag if (unlikely(wake_flags & WF_EXEC)) return prev_cpu; - if (SCX_HAS_OP(select_cpu)) { + if (SCX_HAS_OP(select_cpu) && !scx_rq_bypassing(task_rq(p))) { s32 cpu; struct task_struct **ddsp_taskp; @@ -3193,7 +3215,7 @@ void __scx_update_idle(struct rq *rq, bool idle) { int cpu = cpu_of(rq); - if (SCX_HAS_OP(update_idle)) { + if (SCX_HAS_OP(update_idle) && !scx_rq_bypassing(rq)) { SCX_CALL_OP(SCX_KF_REST, update_idle, cpu_of(rq), idle); if (!static_branch_unlikely(&scx_builtin_idle_enabled)) return; @@ -4048,7 +4070,6 @@ static void scx_cgroup_exit(void) percpu_rwsem_assert_held(&scx_cgroup_rwsem); - WARN_ON_ONCE(!scx_cgroup_enabled); scx_cgroup_enabled = false; /* @@ -4117,6 +4138,7 @@ static int scx_cgroup_init(void) css->cgroup, &args); if (ret) { css_put(css); + scx_ops_error("ops.cgroup_init() failed (%d)", ret); return ret; } tg->scx_flags |= SCX_TG_INITED; @@ -4256,21 +4278,23 @@ bool task_should_scx(struct task_struct *p) * the DISABLING state and then cycling the queued tasks through dequeue/enqueue * to force global FIFO scheduling. * - * a. ops.enqueue() is ignored and tasks are queued in simple global FIFO order. - * %SCX_OPS_ENQ_LAST is also ignored. + * - ops.select_cpu() is ignored and the default select_cpu() is used. + * + * - ops.enqueue() is ignored and tasks are queued in simple global FIFO order. + * %SCX_OPS_ENQ_LAST is also ignored. * - * b. ops.dispatch() is ignored. + * - ops.dispatch() is ignored. * - * c. balance_scx() does not set %SCX_RQ_BAL_KEEP on non-zero slice as slice - * can't be trusted. Whenever a tick triggers, the running task is rotated to - * the tail of the queue with core_sched_at touched. + * - balance_scx() does not set %SCX_RQ_BAL_KEEP on non-zero slice as slice + * can't be trusted. Whenever a tick triggers, the running task is rotated to + * the tail of the queue with core_sched_at touched. * - * d. pick_next_task() suppresses zero slice warning. + * - pick_next_task() suppresses zero slice warning. * - * e. scx_bpf_kick_cpu() is disabled to avoid irq_work malfunction during PM - * operations. + * - scx_bpf_kick_cpu() is disabled to avoid irq_work malfunction during PM + * operations. * - * f. scx_prio_less() reverts to the default core_sched_at order. + * - scx_prio_less() reverts to the default core_sched_at order. */ static void scx_ops_bypass(bool bypass) { @@ -4340,7 +4364,7 @@ static void scx_ops_bypass(bool bypass) rq_unlock_irqrestore(rq, &rf); - /* kick to restore ticks */ + /* resched to restore ticks and idle state */ resched_cpu(cpu); } } @@ -4462,15 +4486,13 @@ static void scx_ops_disable_workfn(struct kthread_work *work) scx_ops_init_task_enabled = false; - spin_lock_irq(&scx_tasks_lock); - scx_task_iter_init(&sti); + scx_task_iter_start(&sti); while ((p = scx_task_iter_next_locked(&sti))) { const struct sched_class *old_class = p->sched_class; struct sched_enq_and_set_ctx ctx; sched_deq_and_put_task(p, DEQUEUE_SAVE | DEQUEUE_MOVE, &ctx); - p->scx.slice = min_t(u64, p->scx.slice, SCX_SLICE_DFL); p->sched_class = __setscheduler_class(p, p->prio); check_class_changing(task_rq(p), p, old_class); @@ -4479,8 +4501,7 @@ static void scx_ops_disable_workfn(struct kthread_work *work) check_class_changed(task_rq(p), p, old_class, p->prio); scx_ops_exit_task(p); } - scx_task_iter_exit(&sti); - spin_unlock_irq(&scx_tasks_lock); + scx_task_iter_stop(&sti); percpu_up_write(&scx_fork_rwsem); /* no task is on scx, turn off all the switches and flush in-progress calls */ @@ -5041,6 +5062,7 @@ static int scx_ops_enable(struct sched_ext_ops *ops, struct bpf_link *link) if (ret) { ret = ops_sanitize_err("init", ret); cpus_read_unlock(); + scx_ops_error("ops.init() failed (%d)", ret); goto err_disable; } } @@ -5130,8 +5152,7 @@ static int scx_ops_enable(struct sched_ext_ops *ops, struct bpf_link *link) if (ret) goto err_disable_unlock_all; - spin_lock_irq(&scx_tasks_lock); - scx_task_iter_init(&sti); + scx_task_iter_start(&sti); while ((p = scx_task_iter_next_locked(&sti))) { /* * @p may already be dead, have lost all its usages counts and @@ -5141,27 +5162,24 @@ static int scx_ops_enable(struct sched_ext_ops *ops, struct bpf_link *link) if (!tryget_task_struct(p)) continue; - scx_task_iter_rq_unlock(&sti); - spin_unlock_irq(&scx_tasks_lock); + scx_task_iter_unlock(&sti); ret = scx_ops_init_task(p, task_group(p), false); if (ret) { put_task_struct(p); - spin_lock_irq(&scx_tasks_lock); - scx_task_iter_exit(&sti); - spin_unlock_irq(&scx_tasks_lock); - pr_err("sched_ext: ops.init_task() failed (%d) for %s[%d] while loading\n", - ret, p->comm, p->pid); + scx_task_iter_relock(&sti); + scx_task_iter_stop(&sti); + scx_ops_error("ops.init_task() failed (%d) for %s[%d]", + ret, p->comm, p->pid); goto err_disable_unlock_all; } scx_set_task_state(p, SCX_TASK_READY); put_task_struct(p); - spin_lock_irq(&scx_tasks_lock); + scx_task_iter_relock(&sti); } - scx_task_iter_exit(&sti); - spin_unlock_irq(&scx_tasks_lock); + scx_task_iter_stop(&sti); scx_cgroup_unlock(); percpu_up_write(&scx_fork_rwsem); @@ -5178,14 +5196,14 @@ static int scx_ops_enable(struct sched_ext_ops *ops, struct bpf_link *link) * scx_tasks_lock. */ percpu_down_write(&scx_fork_rwsem); - spin_lock_irq(&scx_tasks_lock); - scx_task_iter_init(&sti); + scx_task_iter_start(&sti); while ((p = scx_task_iter_next_locked(&sti))) { const struct sched_class *old_class = p->sched_class; struct sched_enq_and_set_ctx ctx; sched_deq_and_put_task(p, DEQUEUE_SAVE | DEQUEUE_MOVE, &ctx); + p->scx.slice = SCX_SLICE_DFL; p->sched_class = __setscheduler_class(p, p->prio); check_class_changing(task_rq(p), p, old_class); @@ -5193,20 +5211,13 @@ static int scx_ops_enable(struct sched_ext_ops *ops, struct bpf_link *link) check_class_changed(task_rq(p), p, old_class, p->prio); } - scx_task_iter_exit(&sti); - spin_unlock_irq(&scx_tasks_lock); + scx_task_iter_stop(&sti); percpu_up_write(&scx_fork_rwsem); scx_ops_bypass(false); - /* - * Returning an error code here would lose the recorded error - * information. Exit indicating success so that the error is notified - * through ops.exit() with all the details. - */ if (!scx_ops_tryset_enable_state(SCX_OPS_ENABLED, SCX_OPS_ENABLING)) { WARN_ON_ONCE(atomic_read(&scx_exit_kind) == SCX_EXIT_NONE); - ret = 0; goto err_disable; } @@ -5241,10 +5252,18 @@ err_disable_unlock_all: scx_ops_bypass(false); err_disable: mutex_unlock(&scx_ops_enable_mutex); - /* must be fully disabled before returning */ - scx_ops_disable(SCX_EXIT_ERROR); + /* + * Returning an error code here would not pass all the error information + * to userspace. Record errno using scx_ops_error() for cases + * scx_ops_error() wasn't already invoked and exit indicating success so + * that the error is notified through ops.exit() with all the details. + * + * Flush scx_ops_disable_work to ensure that error is reported before + * init completion. + */ + scx_ops_error("scx_ops_enable() failed (%d)", ret); kthread_flush_work(&scx_ops_disable_work); - return ret; + return 0; } @@ -5864,16 +5883,21 @@ __bpf_kfunc_start_defs(); __bpf_kfunc s32 scx_bpf_select_cpu_dfl(struct task_struct *p, s32 prev_cpu, u64 wake_flags, bool *is_idle) { - if (!scx_kf_allowed(SCX_KF_SELECT_CPU)) { - *is_idle = false; - return prev_cpu; + if (!static_branch_likely(&scx_builtin_idle_enabled)) { + scx_ops_error("built-in idle tracking is disabled"); + goto prev_cpu; } + + if (!scx_kf_allowed(SCX_KF_SELECT_CPU)) + goto prev_cpu; + #ifdef CONFIG_SMP return scx_select_cpu_dfl(p, prev_cpu, wake_flags, is_idle); -#else +#endif + +prev_cpu: *is_idle = false; return prev_cpu; -#endif } __bpf_kfunc_end_defs(); diff --git a/kernel/sched/psi.c b/kernel/sched/psi.c index 020d58967d4e..84dad1511d1e 100644 --- a/kernel/sched/psi.c +++ b/kernel/sched/psi.c @@ -769,12 +769,13 @@ static void record_times(struct psi_group_cpu *groupc, u64 now) } static void psi_group_change(struct psi_group *group, int cpu, - unsigned int clear, unsigned int set, u64 now, + unsigned int clear, unsigned int set, bool wake_clock) { struct psi_group_cpu *groupc; unsigned int t, m; u32 state_mask; + u64 now; lockdep_assert_rq_held(cpu_rq(cpu)); groupc = per_cpu_ptr(group->pcpu, cpu); @@ -789,6 +790,7 @@ static void psi_group_change(struct psi_group *group, int cpu, * SOME and FULL time these may have resulted in. */ write_seqcount_begin(&groupc->seq); + now = cpu_clock(cpu); /* * Start with TSK_ONCPU, which doesn't have a corresponding @@ -899,18 +901,15 @@ void psi_task_change(struct task_struct *task, int clear, int set) { int cpu = task_cpu(task); struct psi_group *group; - u64 now; if (!task->pid) return; psi_flags_change(task, clear, set); - now = cpu_clock(cpu); - group = task_psi_group(task); do { - psi_group_change(group, cpu, clear, set, now, true); + psi_group_change(group, cpu, clear, set, true); } while ((group = group->parent)); } @@ -919,7 +918,6 @@ void psi_task_switch(struct task_struct *prev, struct task_struct *next, { struct psi_group *group, *common = NULL; int cpu = task_cpu(prev); - u64 now = cpu_clock(cpu); if (next->pid) { psi_flags_change(next, 0, TSK_ONCPU); @@ -936,7 +934,7 @@ void psi_task_switch(struct task_struct *prev, struct task_struct *next, break; } - psi_group_change(group, cpu, 0, TSK_ONCPU, now, true); + psi_group_change(group, cpu, 0, TSK_ONCPU, true); } while ((group = group->parent)); } @@ -974,7 +972,7 @@ void psi_task_switch(struct task_struct *prev, struct task_struct *next, do { if (group == common) break; - psi_group_change(group, cpu, clear, set, now, wake_clock); + psi_group_change(group, cpu, clear, set, wake_clock); } while ((group = group->parent)); /* @@ -986,7 +984,7 @@ void psi_task_switch(struct task_struct *prev, struct task_struct *next, if ((prev->psi_flags ^ next->psi_flags) & ~TSK_ONCPU) { clear &= ~TSK_ONCPU; for (; group; group = group->parent) - psi_group_change(group, cpu, clear, set, now, wake_clock); + psi_group_change(group, cpu, clear, set, wake_clock); } } } @@ -997,8 +995,8 @@ void psi_account_irqtime(struct rq *rq, struct task_struct *curr, struct task_st int cpu = task_cpu(curr); struct psi_group *group; struct psi_group_cpu *groupc; - u64 now, irq; s64 delta; + u64 irq; if (static_branch_likely(&psi_disabled)) return; @@ -1011,7 +1009,6 @@ void psi_account_irqtime(struct rq *rq, struct task_struct *curr, struct task_st if (prev && task_psi_group(prev) == group) return; - now = cpu_clock(cpu); irq = irq_time_read(cpu); delta = (s64)(irq - rq->psi_irq_time); if (delta < 0) @@ -1019,12 +1016,15 @@ void psi_account_irqtime(struct rq *rq, struct task_struct *curr, struct task_st rq->psi_irq_time = irq; do { + u64 now; + if (!group->enabled) continue; groupc = per_cpu_ptr(group->pcpu, cpu); write_seqcount_begin(&groupc->seq); + now = cpu_clock(cpu); record_times(groupc, now); groupc->times[PSI_IRQ_FULL] += delta; @@ -1223,11 +1223,9 @@ void psi_cgroup_restart(struct psi_group *group) for_each_possible_cpu(cpu) { struct rq *rq = cpu_rq(cpu); struct rq_flags rf; - u64 now; rq_lock_irq(rq, &rf); - now = cpu_clock(cpu); - psi_group_change(group, cpu, 0, 0, now, true); + psi_group_change(group, cpu, 0, 0, true); rq_unlock_irq(rq, &rf); } } diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index fba524c81c63..081519ffab46 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -2292,6 +2292,7 @@ static inline int task_on_rq_migrating(struct task_struct *p) #define WF_SYNC 0x10 /* Waker goes to sleep after wakeup */ #define WF_MIGRATED 0x20 /* Internal use, task got migrated */ #define WF_CURRENT_CPU 0x40 /* Prefer to move the wakee to the current CPU. */ +#define WF_RQ_SELECTED 0x80 /* ->select_task_rq() was called */ #ifdef CONFIG_SMP static_assert(WF_EXEC == SD_BALANCE_EXEC); @@ -2334,6 +2335,7 @@ extern const u32 sched_prio_to_wmult[40]; * ENQUEUE_HEAD - place at front of runqueue (tail if not specified) * ENQUEUE_REPLENISH - CBS (replenish runtime and postpone deadline) * ENQUEUE_MIGRATED - the task was migrated during wakeup + * ENQUEUE_RQ_SELECTED - ->select_task_rq() was called * */ @@ -2360,6 +2362,7 @@ extern const u32 sched_prio_to_wmult[40]; #define ENQUEUE_INITIAL 0x80 #define ENQUEUE_MIGRATING 0x100 #define ENQUEUE_DELAYED 0x200 +#define ENQUEUE_RQ_SELECTED 0x400 #define RETRY_TASK ((void *)-1UL) diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 77dc0b25140e..3ea4f7bb1837 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -2337,9 +2337,12 @@ static struct trace_buffer *alloc_buffer(unsigned long size, unsigned flags, if (!buffer->buffers[cpu]) goto fail_free_buffers; - ret = cpuhp_state_add_instance(CPUHP_TRACE_RB_PREPARE, &buffer->node); - if (ret < 0) - goto fail_free_buffers; + /* If already mapped, do not hook to CPU hotplug */ + if (!start) { + ret = cpuhp_state_add_instance(CPUHP_TRACE_RB_PREPARE, &buffer->node); + if (ret < 0) + goto fail_free_buffers; + } mutex_init(&buffer->mutex); @@ -6725,39 +6728,38 @@ int ring_buffer_subbuf_order_set(struct trace_buffer *buffer, int order) } for_each_buffer_cpu(buffer, cpu) { + struct buffer_data_page *old_free_data_page; + struct list_head old_pages; + unsigned long flags; if (!cpumask_test_cpu(cpu, buffer->cpumask)) continue; cpu_buffer = buffer->buffers[cpu]; + raw_spin_lock_irqsave(&cpu_buffer->reader_lock, flags); + /* Clear the head bit to make the link list normal to read */ rb_head_page_deactivate(cpu_buffer); - /* Now walk the list and free all the old sub buffers */ - list_for_each_entry_safe(bpage, tmp, cpu_buffer->pages, list) { - list_del_init(&bpage->list); - free_buffer_page(bpage); - } - /* The above loop stopped an the last page needing to be freed */ - bpage = list_entry(cpu_buffer->pages, struct buffer_page, list); - free_buffer_page(bpage); - - /* Free the current reader page */ - free_buffer_page(cpu_buffer->reader_page); + /* + * Collect buffers from the cpu_buffer pages list and the + * reader_page on old_pages, so they can be freed later when not + * under a spinlock. The pages list is a linked list with no + * head, adding old_pages turns it into a regular list with + * old_pages being the head. + */ + list_add(&old_pages, cpu_buffer->pages); + list_add(&cpu_buffer->reader_page->list, &old_pages); /* One page was allocated for the reader page */ cpu_buffer->reader_page = list_entry(cpu_buffer->new_pages.next, struct buffer_page, list); list_del_init(&cpu_buffer->reader_page->list); - /* The cpu_buffer pages are a link list with no head */ + /* Install the new pages, remove the head from the list */ cpu_buffer->pages = cpu_buffer->new_pages.next; - cpu_buffer->new_pages.next->prev = cpu_buffer->new_pages.prev; - cpu_buffer->new_pages.prev->next = cpu_buffer->new_pages.next; - - /* Clear the new_pages list */ - INIT_LIST_HEAD(&cpu_buffer->new_pages); + list_del_init(&cpu_buffer->new_pages); cpu_buffer->head_page = list_entry(cpu_buffer->pages, struct buffer_page, list); @@ -6766,11 +6768,20 @@ int ring_buffer_subbuf_order_set(struct trace_buffer *buffer, int order) cpu_buffer->nr_pages = cpu_buffer->nr_pages_to_update; cpu_buffer->nr_pages_to_update = 0; - free_pages((unsigned long)cpu_buffer->free_page, old_order); + old_free_data_page = cpu_buffer->free_page; cpu_buffer->free_page = NULL; rb_head_page_activate(cpu_buffer); + raw_spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags); + + /* Free old sub buffers */ + list_for_each_entry_safe(bpage, tmp, &old_pages, list) { + list_del_init(&bpage->list); + free_buffer_page(bpage); + } + free_pages((unsigned long)old_free_data_page, old_order); + rb_check_pages(cpu_buffer); } diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index c01375adc471..a8f52b6527ca 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -3697,8 +3697,8 @@ static void test_can_verify(void) void trace_check_vprintf(struct trace_iterator *iter, const char *fmt, va_list ap) { - long text_delta = iter->tr->text_delta; - long data_delta = iter->tr->data_delta; + long text_delta = 0; + long data_delta = 0; const char *p = fmt; const char *str; bool good; @@ -3710,6 +3710,17 @@ void trace_check_vprintf(struct trace_iterator *iter, const char *fmt, if (static_branch_unlikely(&trace_no_verify)) goto print; + /* + * When the kernel is booted with the tp_printk command line + * parameter, trace events go directly through to printk(). + * It also is checked by this function, but it does not + * have an associated trace_array (tr) for it. + */ + if (iter->tr) { + text_delta = iter->tr->text_delta; + data_delta = iter->tr->data_delta; + } + /* Don't bother checking when doing a ftrace_dump() */ if (iter->fmt == static_fmt_buf) goto print; @@ -10610,10 +10621,10 @@ __init static void enable_instances(void) * cannot be deleted by user space, so keep the reference * to it. */ - if (start) + if (start) { tr->flags |= TRACE_ARRAY_FL_BOOT; - else - trace_array_put(tr); + tr->ref++; + } while ((tok = strsep(&curr_str, ","))) { early_enable_events(tr, tok, true); diff --git a/kernel/trace/trace_hwlat.c b/kernel/trace/trace_hwlat.c index b791524a6536..3bd6071441ad 100644 --- a/kernel/trace/trace_hwlat.c +++ b/kernel/trace/trace_hwlat.c @@ -520,6 +520,8 @@ static void hwlat_hotplug_workfn(struct work_struct *dummy) if (!hwlat_busy || hwlat_data.thread_mode != MODE_PER_CPU) goto out_unlock; + if (!cpu_online(cpu)) + goto out_unlock; if (!cpumask_test_cpu(cpu, tr->tracing_cpumask)) goto out_unlock; diff --git a/kernel/trace/trace_osnoise.c b/kernel/trace/trace_osnoise.c index 1439064f65d6..a50ed23bee77 100644 --- a/kernel/trace/trace_osnoise.c +++ b/kernel/trace/trace_osnoise.c @@ -1953,12 +1953,8 @@ static void stop_kthread(unsigned int cpu) { struct task_struct *kthread; - mutex_lock(&interface_lock); - kthread = per_cpu(per_cpu_osnoise_var, cpu).kthread; + kthread = xchg_relaxed(&(per_cpu(per_cpu_osnoise_var, cpu).kthread), NULL); if (kthread) { - per_cpu(per_cpu_osnoise_var, cpu).kthread = NULL; - mutex_unlock(&interface_lock); - if (cpumask_test_and_clear_cpu(cpu, &kthread_cpumask) && !WARN_ON(!test_bit(OSN_WORKLOAD, &osnoise_options))) { kthread_stop(kthread); @@ -1972,7 +1968,6 @@ static void stop_kthread(unsigned int cpu) put_task_struct(kthread); } } else { - mutex_unlock(&interface_lock); /* if no workload, just return */ if (!test_bit(OSN_WORKLOAD, &osnoise_options)) { /* @@ -1994,8 +1989,12 @@ static void stop_per_cpu_kthreads(void) { int cpu; - for_each_possible_cpu(cpu) + cpus_read_lock(); + + for_each_online_cpu(cpu) stop_kthread(cpu); + + cpus_read_unlock(); } /* @@ -2007,6 +2006,10 @@ static int start_kthread(unsigned int cpu) void *main = osnoise_main; char comm[24]; + /* Do not start a new thread if it is already running */ + if (per_cpu(per_cpu_osnoise_var, cpu).kthread) + return 0; + if (timerlat_enabled()) { snprintf(comm, 24, "timerlat/%d", cpu); main = timerlat_main; @@ -2061,11 +2064,10 @@ static int start_per_cpu_kthreads(void) if (cpumask_test_and_clear_cpu(cpu, &kthread_cpumask)) { struct task_struct *kthread; - kthread = per_cpu(per_cpu_osnoise_var, cpu).kthread; + kthread = xchg_relaxed(&(per_cpu(per_cpu_osnoise_var, cpu).kthread), NULL); if (!WARN_ON(!kthread)) kthread_stop(kthread); } - per_cpu(per_cpu_osnoise_var, cpu).kthread = NULL; } for_each_cpu(cpu, current_mask) { @@ -2095,6 +2097,8 @@ static void osnoise_hotplug_workfn(struct work_struct *dummy) mutex_lock(&interface_lock); cpus_read_lock(); + if (!cpu_online(cpu)) + goto out_unlock; if (!cpumask_test_cpu(cpu, &osnoise_cpumask)) goto out_unlock; |