Dear RT Folks, I'm pleased to announce the 3.12.61-rt82 stable release.
You can get this release via the git tree at: git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-stable-rt.git branch: v3.12-rt Head SHA1: 275c808f91fc8e1873873718290a7f242fe127cd Or to build 3.12.61-rt82 directly, the following patches should be applied: http://www.kernel.org/pub/linux/kernel/v3.x/linux-3.12.tar.xz http://www.kernel.org/pub/linux/kernel/v3.x/patch-3.12.61.xz http://www.kernel.org/pub/linux/kernel/projects/rt/3.12/patch-3.12.61-rt82.patch.xz You can also build from 3.12.61-rt81 by applying the incremental patch: http://www.kernel.org/pub/linux/kernel/projects/rt/3.12/incr/patch-3.12.61-rt81-rt82.patch.xz Enjoy, -- Steve Changes from v3.12.61-rt81: --- Corey Minyard (1): x86: Fix an RT MCE crash Josh Cartwright (1): list_bl: fixup bogus lockdep warning Luiz Capitulino (1): mm: perform lru_add_drain_all() remotely Rik van Riel (1): kvm, rt: change async pagefault code locking for PREEMPT_RT Sebastian Andrzej Siewior (5): net: dev: always take qdisc's busylock in __dev_xmit_skb() kernel/printk: Don't try to print from IRQ/NMI region arm: lazy preempt: correct resched condition locallock: add local_lock_on() trace: correct off by one while recording the trace-event Steven Rostedt (Red Hat) (1): Linux 3.12.61-rt82 ---- arch/arm/kernel/entry-armv.S | 6 +++++- arch/x86/kernel/cpu/mcheck/mce.c | 3 ++- arch/x86/kernel/kvm.c | 37 +++++++++++++++++++------------------ include/linux/list_bl.h | 12 +++++++----- include/linux/locallock.h | 6 ++++++ include/trace/ftrace.h | 3 +++ kernel/printk/printk.c | 10 ++++++++++ localversion-rt | 2 +- mm/swap.c | 37 ++++++++++++++++++++++++++++++------- net/core/dev.c | 4 ++++ 10 files changed, 87 insertions(+), 33 deletions(-) --------------------------- diff --git a/arch/arm/kernel/entry-armv.S b/arch/arm/kernel/entry-armv.S index 8c5e809c1f07..96eb4d26a5c1 100644 --- a/arch/arm/kernel/entry-armv.S +++ b/arch/arm/kernel/entry-armv.S @@ -234,7 +234,11 @@ svc_preempt: bne 1b tst r0, #_TIF_NEED_RESCHED_LAZY moveq pc, r8 @ go again - b 1b + ldr r0, [tsk, #TI_PREEMPT_LAZY] @ get preempt lazy count + teq r0, #0 @ if preempt lazy count != 0 + beq 1b + mov pc, r8 @ go again + #endif __und_fault: diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c index 3a7ab0b08cdf..9901b77ed819 100644 --- a/arch/x86/kernel/cpu/mcheck/mce.c +++ b/arch/x86/kernel/cpu/mcheck/mce.c @@ -1403,7 +1403,8 @@ static int mce_notify_work_init(void) static void mce_notify_work(void) { - wake_up_process(mce_notify_helper); + if (mce_notify_helper) + wake_up_process(mce_notify_helper); } #else static void mce_notify_work(void) diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c index e72593338df6..7e640682699d 100644 --- a/arch/x86/kernel/kvm.c +++ b/arch/x86/kernel/kvm.c @@ -35,6 +35,7 @@ #include <linux/slab.h> #include <linux/kprobes.h> #include <linux/debugfs.h> +#include <linux/wait-simple.h> #include <asm/timer.h> #include <asm/cpu.h> #include <asm/traps.h> @@ -90,14 +91,14 @@ static void kvm_io_delay(void) struct kvm_task_sleep_node { struct hlist_node link; - wait_queue_head_t wq; + struct swait_head wq; u32 token; int cpu; bool halted; }; static struct kvm_task_sleep_head { - spinlock_t lock; + raw_spinlock_t lock; struct hlist_head list; } async_pf_sleepers[KVM_TASK_SLEEP_HASHSIZE]; @@ -121,17 +122,17 @@ void kvm_async_pf_task_wait(u32 token) u32 key = hash_32(token, KVM_TASK_SLEEP_HASHBITS); struct kvm_task_sleep_head *b = &async_pf_sleepers[key]; struct kvm_task_sleep_node n, *e; - DEFINE_WAIT(wait); + DEFINE_SWAITER(wait); rcu_irq_enter(); - spin_lock(&b->lock); + raw_spin_lock(&b->lock); e = _find_apf_task(b, token); if (e) { /* dummy entry exist -> wake up was delivered ahead of PF */ hlist_del(&e->link); kfree(e); - spin_unlock(&b->lock); + raw_spin_unlock(&b->lock); rcu_irq_exit(); return; @@ -140,13 +141,13 @@ void kvm_async_pf_task_wait(u32 token) n.token = token; n.cpu = smp_processor_id(); n.halted = is_idle_task(current) || preempt_count() > 1; - init_waitqueue_head(&n.wq); + init_swait_head(&n.wq); hlist_add_head(&n.link, &b->list); - spin_unlock(&b->lock); + raw_spin_unlock(&b->lock); for (;;) { if (!n.halted) - prepare_to_wait(&n.wq, &wait, TASK_UNINTERRUPTIBLE); + swait_prepare(&n.wq, &wait, TASK_UNINTERRUPTIBLE); if (hlist_unhashed(&n.link)) break; @@ -165,7 +166,7 @@ void kvm_async_pf_task_wait(u32 token) } } if (!n.halted) - finish_wait(&n.wq, &wait); + swait_finish(&n.wq, &wait); rcu_irq_exit(); return; @@ -177,8 +178,8 @@ static void apf_task_wake_one(struct kvm_task_sleep_node *n) hlist_del_init(&n->link); if (n->halted) smp_send_reschedule(n->cpu); - else if (waitqueue_active(&n->wq)) - wake_up(&n->wq); + else if (swaitqueue_active(&n->wq)) + swait_wake(&n->wq); } static void apf_task_wake_all(void) @@ -188,14 +189,14 @@ static void apf_task_wake_all(void) for (i = 0; i < KVM_TASK_SLEEP_HASHSIZE; i++) { struct hlist_node *p, *next; struct kvm_task_sleep_head *b = &async_pf_sleepers[i]; - spin_lock(&b->lock); + raw_spin_lock(&b->lock); hlist_for_each_safe(p, next, &b->list) { struct kvm_task_sleep_node *n = hlist_entry(p, typeof(*n), link); if (n->cpu == smp_processor_id()) apf_task_wake_one(n); } - spin_unlock(&b->lock); + raw_spin_unlock(&b->lock); } } @@ -211,7 +212,7 @@ void kvm_async_pf_task_wake(u32 token) } again: - spin_lock(&b->lock); + raw_spin_lock(&b->lock); n = _find_apf_task(b, token); if (!n) { /* @@ -224,17 +225,17 @@ again: * Allocation failed! Busy wait while other cpu * handles async PF. */ - spin_unlock(&b->lock); + raw_spin_unlock(&b->lock); cpu_relax(); goto again; } n->token = token; n->cpu = smp_processor_id(); - init_waitqueue_head(&n->wq); + init_swait_head(&n->wq); hlist_add_head(&n->link, &b->list); } else apf_task_wake_one(n); - spin_unlock(&b->lock); + raw_spin_unlock(&b->lock); return; } EXPORT_SYMBOL_GPL(kvm_async_pf_task_wake); @@ -484,7 +485,7 @@ void __init kvm_guest_init(void) paravirt_ops_setup(); register_reboot_notifier(&kvm_pv_reboot_nb); for (i = 0; i < KVM_TASK_SLEEP_HASHSIZE; i++) - spin_lock_init(&async_pf_sleepers[i].lock); + raw_spin_lock_init(&async_pf_sleepers[i].lock); if (kvm_para_has_feature(KVM_FEATURE_ASYNC_PF)) x86_init.irqs.trap_init = kvm_apf_trap_init; diff --git a/include/linux/list_bl.h b/include/linux/list_bl.h index d8876a0cf036..017d0f1c1eb4 100644 --- a/include/linux/list_bl.h +++ b/include/linux/list_bl.h @@ -42,13 +42,15 @@ struct hlist_bl_node { struct hlist_bl_node *next, **pprev; }; -static inline void INIT_HLIST_BL_HEAD(struct hlist_bl_head *h) -{ - h->first = NULL; #ifdef CONFIG_PREEMPT_RT_BASE - raw_spin_lock_init(&h->lock); +#define INIT_HLIST_BL_HEAD(h) \ +do { \ + (h)->first = NULL; \ + raw_spin_lock_init(&(h)->lock); \ +} while (0) +#else +#define INIT_HLIST_BL_HEAD(h) (h)->first = NULL #endif -} static inline void INIT_HLIST_BL_NODE(struct hlist_bl_node *h) { diff --git a/include/linux/locallock.h b/include/linux/locallock.h index 21653e9bfa20..015271ff8ec8 100644 --- a/include/linux/locallock.h +++ b/include/linux/locallock.h @@ -66,6 +66,9 @@ static inline void __local_lock(struct local_irq_lock *lv) #define local_lock(lvar) \ do { __local_lock(&get_local_var(lvar)); } while (0) +#define local_lock_on(lvar, cpu) \ + do { __local_lock(&per_cpu(lvar, cpu)); } while (0) + static inline int __local_trylock(struct local_irq_lock *lv) { if (lv->owner != current && spin_trylock_local(&lv->lock)) { @@ -104,6 +107,9 @@ static inline void __local_unlock(struct local_irq_lock *lv) put_local_var(lvar); \ } while (0) +#define local_unlock_on(lvar, cpu) \ + do { __local_unlock(&per_cpu(lvar, cpu)); } while (0) + static inline void __local_lock_irq(struct local_irq_lock *lv) { spin_lock_irqsave(&lv->lock, lv->flags); diff --git a/include/trace/ftrace.h b/include/trace/ftrace.h index 645d749d3c9c..1c74dcd4c76e 100644 --- a/include/trace/ftrace.h +++ b/include/trace/ftrace.h @@ -536,6 +536,9 @@ ftrace_raw_event_##call(void *__data, proto) \ \ local_save_flags(irq_flags); \ pc = preempt_count(); \ + /* Account for tracepoint preempt disable */ \ + if (IS_ENABLED(CONFIG_PREEMPT)) \ + pc--; \ \ __data_size = ftrace_get_offsets_##call(&__data_offsets, args); \ \ diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index 9a751f6c471e..7283909a9943 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -1293,6 +1293,11 @@ static void call_console_drivers(int level, const char *text, size_t len) if (!console_drivers) return; + if (IS_ENABLED(CONFIG_PREEMPT_RT_BASE)) { + if (in_irq() || in_nmi()) + return; + } + migrate_disable(); for_each_console(con) { if (exclusive_console && con != exclusive_console) @@ -2215,6 +2220,11 @@ void console_unblank(void) { struct console *c; + if (IS_ENABLED(CONFIG_PREEMPT_RT_BASE)) { + if (in_irq() || in_nmi()) + return; + } + /* * console_unblank can no longer be called in interrupt context unless * oops_in_progress is set to 1.. diff --git a/localversion-rt b/localversion-rt index 8269ec129c0c..56556986917c 100644 --- a/localversion-rt +++ b/localversion-rt @@ -1 +1 @@ --rt81 +-rt82 diff --git a/mm/swap.c b/mm/swap.c index 8ab73ba62a68..05e75d61c707 100644 --- a/mm/swap.c +++ b/mm/swap.c @@ -718,9 +718,15 @@ void lru_add_drain_cpu(int cpu) unsigned long flags; /* No harm done if a racing interrupt already did this */ +#ifdef CONFIG_PREEMPT_RT_BASE + local_lock_irqsave_on(rotate_lock, flags, cpu); + pagevec_move_tail(pvec); + local_unlock_irqrestore_on(rotate_lock, flags, cpu); +#else local_lock_irqsave(rotate_lock, flags); pagevec_move_tail(pvec); local_unlock_irqrestore(rotate_lock, flags); +#endif } pvec = &per_cpu(lru_deactivate_pvecs, cpu); @@ -763,12 +769,32 @@ void lru_add_drain(void) local_unlock_cpu(swapvec_lock); } + +#ifdef CONFIG_PREEMPT_RT_BASE +static inline void remote_lru_add_drain(int cpu, struct cpumask *has_work) +{ + local_lock_on(swapvec_lock, cpu); + lru_add_drain_cpu(cpu); + local_unlock_on(swapvec_lock, cpu); +} + +#else + static void lru_add_drain_per_cpu(struct work_struct *dummy) { lru_add_drain(); } static DEFINE_PER_CPU(struct work_struct, lru_add_drain_work); +static inline void remote_lru_add_drain(int cpu, struct cpumask *has_work) +{ + struct work_struct *work = &per_cpu(lru_add_drain_work, cpu); + + INIT_WORK(work, lru_add_drain_per_cpu); + schedule_work_on(cpu, work); + cpumask_set_cpu(cpu, has_work); +} +#endif void lru_add_drain_all(void) { @@ -781,20 +807,17 @@ void lru_add_drain_all(void) cpumask_clear(&has_work); for_each_online_cpu(cpu) { - struct work_struct *work = &per_cpu(lru_add_drain_work, cpu); - if (pagevec_count(&per_cpu(lru_add_pvec, cpu)) || pagevec_count(&per_cpu(lru_rotate_pvecs, cpu)) || pagevec_count(&per_cpu(lru_deactivate_pvecs, cpu)) || - need_activate_page_drain(cpu)) { - INIT_WORK(work, lru_add_drain_per_cpu); - schedule_work_on(cpu, work); - cpumask_set_cpu(cpu, &has_work); - } + need_activate_page_drain(cpu)) + remote_lru_add_drain(cpu, &has_work); } +#ifndef CONFIG_PREEMPT_RT_BASE for_each_cpu(cpu, &has_work) flush_work(&per_cpu(lru_add_drain_work, cpu)); +#endif put_online_cpus(); mutex_unlock(&lock); diff --git a/net/core/dev.c b/net/core/dev.c index ee08da0fe0d7..c34af0bf3c0e 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -2713,7 +2713,11 @@ static inline int __dev_xmit_skb(struct sk_buff *skb, struct Qdisc *q, * This permits __QDISC_STATE_RUNNING owner to get the lock more often * and dequeue packets faster. */ +#ifdef CONFIG_PREEMPT_RT_FULL + contended = true; +#else contended = qdisc_is_running(q); +#endif if (unlikely(contended)) spin_lock(&q->busylock);
