From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bernhard Landauer Subject: Re: [ANNOUNCE] v4.9.30-rt20 Date: Sat, 27 May 2017 19:19:51 +0200 Message-ID: References: <20170527163230.b7qcfbmwsmbyo7k2@linutronix.de> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Cc: LKML , linux-rt-users , Steven Rostedt To: Sebastian Andrzej Siewior , Thomas Gleixner Return-path: In-Reply-To: <20170527163230.b7qcfbmwsmbyo7k2@linutronix.de> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-rt-users.vger.kernel.org Thanks a lot as always! I have a question regarding packager keys: It seems this time the patch has been signed with a different key than usual: unknown public key 4FE5E3262872E4CC Could you please let me know where you packager keys can be looked up? Thanks regards Bernhard On 27/05/17 18:32, Sebastian Andrzej Siewior wrote: > Dear RT folks! > > I'm pleased to announce the v4.9.30-rt20 patch set. > > Changes since v4.9.30-rt19: > > - The patch "timers: Don't wake ktimersoftd on every tick" has been > reverted because this optimisation can lead to timers not getting > expired. Reported by Klaus Gusenleitner, debugged by Anna-Maria > Gleixner. > > - Markus Trippelsdorf reported that the new futex code makes the > glibc/nptl/tst-robustpi8 test fail. Patch by Peter Zijlstra. > > Known issues > - CPU hotplug got a little better but can deadlock. > > - gdb. While gdb is following a task it is possible that after a > fork() operation the task is waiting for gdb and gdb waiting > for the task. > > The delta patch against v4.9.30-rt19 is appended below and can be found here: > > https://cdn.kernel.org/pub/linux/kernel/projects/rt/4.9/incr/patch-4.9.30-rt19-rt20.patch.xz > > You can get this release via the git tree at: > > git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git v4.9.30-rt20 > > The RT patch against v4.9.30 can be found here: > > https://cdn.kernel.org/pub/linux/kernel/projects/rt/4.9/older/patch-4.9.30-rt20.patch.xz > > The split quilt queue is available at: > > https://cdn.kernel.org/pub/linux/kernel/projects/rt/4.9/older/patches-4.9.30-rt20.tar.xz > > Sebastian > diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c > --- a/kernel/locking/rtmutex.c > +++ b/kernel/locking/rtmutex.c > @@ -2400,11 +2400,14 @@ int rt_mutex_wait_proxy_lock(struct rt_mutex *lock, > int ret; > > raw_spin_lock_irq(&lock->wait_lock); > - > - set_current_state(TASK_INTERRUPTIBLE); > - > /* sleep on the mutex */ > + set_current_state(TASK_INTERRUPTIBLE); > ret = __rt_mutex_slowlock(lock, TASK_INTERRUPTIBLE, to, waiter, NULL); > + /* > + * try_to_take_rt_mutex() sets the waiter bit unconditionally. We might > + * have to fix that up. > + */ > + fixup_rt_mutex_waiters(lock); > > /* > * RT has a problem here when the wait got interrupted by a timeout > @@ -2423,7 +2426,6 @@ int rt_mutex_wait_proxy_lock(struct rt_mutex *lock, > tsk->pi_blocked_on = NULL; > raw_spin_unlock(&tsk->pi_lock); > } > - > raw_spin_unlock_irq(&lock->wait_lock); > > return ret; > @@ -2455,15 +2457,25 @@ bool rt_mutex_cleanup_proxy_lock(struct rt_mutex *lock, > > raw_spin_lock_irq(&lock->wait_lock); > /* > + * Do an unconditional try-lock, this deals with the lock stealing > + * state where __rt_mutex_futex_unlock() -> mark_wakeup_next_waiter() > + * sets a NULL owner. > + * > + * We're not interested in the return value, because the subsequent > + * test on rt_mutex_owner() will infer that. If the trylock succeeded, > + * we will own the lock and it will have removed the waiter. If we > + * failed the trylock, we're still not owner and we need to remove > + * ourselves. > + */ > + try_to_take_rt_mutex(lock, current, waiter); > + /* > * Unless we're the owner; we're still enqueued on the wait_list. > * So check if we became owner, if not, take us off the wait_list. > */ > if (rt_mutex_owner(lock) != current) { > remove_waiter(lock, waiter); > - fixup_rt_mutex_waiters(lock); > cleanup = true; > } > - > /* > * try_to_take_rt_mutex() sets the waiter bit unconditionally. We might > * have to fix that up. > diff --git a/kernel/time/timer.c b/kernel/time/timer.c > --- a/kernel/time/timer.c > +++ b/kernel/time/timer.c > @@ -206,8 +206,6 @@ struct timer_base { > bool is_idle; > DECLARE_BITMAP(pending_map, WHEEL_SIZE); > struct hlist_head vectors[WHEEL_SIZE]; > - struct hlist_head expired_lists[LVL_DEPTH]; > - int expired_count; > } ____cacheline_aligned; > > static DEFINE_PER_CPU(struct timer_base, timer_bases[NR_BASES]); > @@ -1355,8 +1353,7 @@ static void call_timer_fn(struct timer_list *timer, void (*fn)(unsigned long), > } > } > > -static inline void __expire_timers(struct timer_base *base, > - struct hlist_head *head) > +static void expire_timers(struct timer_base *base, struct hlist_head *head) > { > while (!hlist_empty(head)) { > struct timer_list *timer; > @@ -1387,38 +1384,21 @@ static inline void __expire_timers(struct timer_base *base, > } > } > > -static void expire_timers(struct timer_base *base) > -{ > - struct hlist_head *head; > - > - while (base->expired_count--) { > - head = base->expired_lists + base->expired_count; > - __expire_timers(base, head); > - } > - base->expired_count = 0; > -} > - > -static void __collect_expired_timers(struct timer_base *base) > +static int __collect_expired_timers(struct timer_base *base, > + struct hlist_head *heads) > { > unsigned long clk = base->clk; > struct hlist_head *vec; > - int i; > + int i, levels = 0; > unsigned int idx; > > - /* > - * expire_timers() must be called at least once before we can > - * collect more timers > - */ > - if (WARN_ON(base->expired_count)) > - return; > - > for (i = 0; i < LVL_DEPTH; i++) { > idx = (clk & LVL_MASK) + i * LVL_SIZE; > > if (__test_and_clear_bit(idx, base->pending_map)) { > vec = base->vectors + idx; > - hlist_move_list(vec, > - &base->expired_lists[base->expired_count++]); > + hlist_move_list(vec, heads++); > + levels++; > } > /* Is it time to look at the next level? */ > if (clk & LVL_CLK_MASK) > @@ -1426,6 +1406,7 @@ static void __collect_expired_timers(struct timer_base *base) > /* Shift clock for the next level granularity */ > clk >>= LVL_CLK_SHIFT; > } > + return levels; > } > > #ifdef CONFIG_NO_HZ_COMMON > @@ -1618,7 +1599,8 @@ void timer_clear_idle(void) > base->is_idle = false; > } > > -static void collect_expired_timers(struct timer_base *base) > +static int collect_expired_timers(struct timer_base *base, > + struct hlist_head *heads) > { > /* > * NOHZ optimization. After a long idle sleep we need to forward the > @@ -1635,49 +1617,20 @@ static void collect_expired_timers(struct timer_base *base) > if (time_after(next, jiffies)) { > /* The call site will increment clock! */ > base->clk = jiffies - 1; > - return; > + return 0; > } > base->clk = next; > } > - __collect_expired_timers(base); > + return __collect_expired_timers(base, heads); > } > #else > -static inline void collect_expired_timers(struct timer_base *base) > +static inline int collect_expired_timers(struct timer_base *base, > + struct hlist_head *heads) > { > - __collect_expired_timers(base); > + return __collect_expired_timers(base, heads); > } > #endif > > -static int find_expired_timers(struct timer_base *base) > -{ > - const unsigned long int end_clk = jiffies; > - > - while (!base->expired_count && time_after_eq(end_clk, base->clk)) { > - collect_expired_timers(base); > - base->clk++; > - } > - > - return base->expired_count; > -} > - > -/* Called from CPU tick routine to quickly collect expired timers */ > -static int tick_find_expired(struct timer_base *base) > -{ > - int count; > - > - raw_spin_lock(&base->lock); > - > - if (unlikely(time_after(jiffies, base->clk + HZ))) { > - /* defer to ktimersoftd; don't spend too long in irq context */ > - count = -1; > - } else > - count = find_expired_timers(base); > - > - raw_spin_unlock(&base->lock); > - > - return count; > -} > - > /* > * Called from the timer interrupt handler to charge one tick to the current > * process. user_tick is 1 if the tick is user time, 0 for system. > @@ -1704,11 +1657,22 @@ void update_process_times(int user_tick) > */ > static inline void __run_timers(struct timer_base *base) > { > + struct hlist_head heads[LVL_DEPTH]; > + int levels; > + > + if (!time_after_eq(jiffies, base->clk)) > + return; > + > raw_spin_lock_irq(&base->lock); > > - while (find_expired_timers(base)) > - expire_timers(base); > + while (time_after_eq(jiffies, base->clk)) { > > + levels = collect_expired_timers(base, heads); > + base->clk++; > + > + while (levels--) > + expire_timers(base, heads + levels); > + } > raw_spin_unlock_irq(&base->lock); > wakeup_timer_waiters(base); > } > @@ -1736,12 +1700,12 @@ void run_local_timers(void) > > hrtimer_run_queues(); > /* Raise the softirq only if required. */ > - if (time_before(jiffies, base->clk) || !tick_find_expired(base)) { > + if (time_before(jiffies, base->clk)) { > if (!IS_ENABLED(CONFIG_NO_HZ_COMMON) || !base->nohz_active) > return; > /* CPU is awake, so check the deferrable base. */ > base++; > - if (time_before(jiffies, base->clk) || !tick_find_expired(base)) > + if (time_before(jiffies, base->clk)) > return; > } > raise_softirq(TIMER_SOFTIRQ); > @@ -1911,7 +1875,6 @@ int timers_dead_cpu(unsigned int cpu) > raw_spin_lock_nested(&old_base->lock, SINGLE_DEPTH_NESTING); > > BUG_ON(old_base->running_timer); > - BUG_ON(old_base->expired_count); > > for (i = 0; i < WHEEL_SIZE; i++) > migrate_timer_list(new_base, old_base->vectors + i); > @@ -1938,7 +1901,6 @@ static void __init init_timer_cpu(int cpu) > #ifdef CONFIG_PREEMPT_RT_FULL > init_swait_queue_head(&base->wait_for_running_timer); > #endif > - base->expired_count = 0; > } > } > > diff --git a/localversion-rt b/localversion-rt > --- a/localversion-rt > +++ b/localversion-rt > @@ -1 +1 @@ > --rt19 > +-rt20 > -- > To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html