From b421b22b00b0011f6a2ce3561176c4e79e640c49 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Fri, 21 Apr 2017 12:14:13 +0200 Subject: x86/tsc, sched/clock, clocksource: Use clocksource watchdog to provide stable sync points Currently we keep sched_clock_tick() active for stable TSC in order to keep the per-CPU state semi up-to-date. The (obvious) problem is that by the time we detect TSC is borked, our per-CPU state is also borked. So hook into the clocksource watchdog and call a method after we've found it to still be stable. There's the obvious race where the TSC goes wonky between finding it stable and us running the callback, but closing that is too much work and not really worth it, since we're already detecting TSC wobbles after the fact, so we cannot, per definition, fully avoid funny clock values. And since the watchdog runs less often than the tick, this is also an optimization. Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Mike Galbraith Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar --- include/linux/clocksource.h | 1 + include/linux/sched/clock.h | 2 +- 2 files changed, 2 insertions(+), 1 deletion(-) (limited to 'include/linux') diff --git a/include/linux/clocksource.h b/include/linux/clocksource.h index f2b10d9ebd04..81490456c242 100644 --- a/include/linux/clocksource.h +++ b/include/linux/clocksource.h @@ -96,6 +96,7 @@ struct clocksource { void (*suspend)(struct clocksource *cs); void (*resume)(struct clocksource *cs); void (*mark_unstable)(struct clocksource *cs); + void (*tick_stable)(struct clocksource *cs); /* private: */ #ifdef CONFIG_CLOCKSOURCE_WATCHDOG diff --git a/include/linux/sched/clock.h b/include/linux/sched/clock.h index 34fe92ce1ebd..978cbb0af5f3 100644 --- a/include/linux/sched/clock.h +++ b/include/linux/sched/clock.h @@ -63,8 +63,8 @@ extern void clear_sched_clock_stable(void); */ extern u64 __sched_clock_offset; - extern void sched_clock_tick(void); +extern void sched_clock_tick_stable(void); extern void sched_clock_idle_sleep_event(void); extern void sched_clock_idle_wakeup_event(u64 delta_ns); -- cgit v1.2.3 From ac1e843f0900bea92fcb47f6205e1f9ffb0d469c Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Fri, 21 Apr 2017 12:26:23 +0200 Subject: sched/clock: Remove unused argument to sched_clock_idle_wakeup_event() The argument to sched_clock_idle_wakeup_event() has not been used in a long time. Remove it. Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Mike Galbraith Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar --- include/linux/sched/clock.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'include/linux') diff --git a/include/linux/sched/clock.h b/include/linux/sched/clock.h index 978cbb0af5f3..9c36f0722966 100644 --- a/include/linux/sched/clock.h +++ b/include/linux/sched/clock.h @@ -39,7 +39,7 @@ static inline void sched_clock_idle_sleep_event(void) { } -static inline void sched_clock_idle_wakeup_event(u64 delta_ns) +static inline void sched_clock_idle_wakeup_event(void) { } @@ -66,7 +66,7 @@ extern u64 __sched_clock_offset; extern void sched_clock_tick(void); extern void sched_clock_tick_stable(void); extern void sched_clock_idle_sleep_event(void); -extern void sched_clock_idle_wakeup_event(u64 delta_ns); +extern void sched_clock_idle_wakeup_event(void); /* * As outlined in clock.c, provides a fast, high resolution, nanosecond -- cgit v1.2.3 From 2e44b7ddf8ab01cf98106c68388f87af15fbde73 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Fri, 21 Apr 2017 12:46:57 +0200 Subject: sched/clock: Use late_initcall() instead of sched_init_smp() Core2 marks its TSC unstable in ACPI Processor Idle, which is probed after sched_init_smp(). Luckily it appears both acpi_processor and intel_idle (which has a similar check) are mandatory built-in. This means we can delay switching to stable until after these drivers have ran (if they were modules, this would be impossible). Delay the stable switch to late_initcall() to allow these drivers to mark TSC unstable and avoid difficult stable->unstable transitions. Reported-by: Lofstedt, Marta Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Mike Galbraith Cc: Peter Zijlstra Cc: Rafael J . Wysocki Cc: Thomas Gleixner Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar --- include/linux/sched/clock.h | 5 ----- 1 file changed, 5 deletions(-) (limited to 'include/linux') diff --git a/include/linux/sched/clock.h b/include/linux/sched/clock.h index 9c36f0722966..a55600ffdf4b 100644 --- a/include/linux/sched/clock.h +++ b/include/linux/sched/clock.h @@ -23,10 +23,6 @@ extern u64 sched_clock_cpu(int cpu); extern void sched_clock_init(void); #ifndef CONFIG_HAVE_UNSTABLE_SCHED_CLOCK -static inline void sched_clock_init_late(void) -{ -} - static inline void sched_clock_tick(void) { } @@ -53,7 +49,6 @@ static inline u64 local_clock(void) return sched_clock(); } #else -extern void sched_clock_init_late(void); extern int sched_clock_stable(void); extern void clear_sched_clock_stable(void); -- cgit v1.2.3 From c743f0a5c50f2fcbc628526279cfa24f3dabe182 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Fri, 14 Apr 2017 14:20:05 +0200 Subject: sched/fair, cpumask: Export for_each_cpu_wrap() More users for for_each_cpu_wrap() have appeared. Promote the construct to generic cpumask interface. The implementation is slightly modified to reduce arguments. Signed-off-by: Peter Zijlstra (Intel) Cc: Lauro Ramos Venancio Cc: Linus Torvalds Cc: Mike Galbraith Cc: Peter Zijlstra Cc: Rik van Riel Cc: Thomas Gleixner Cc: lwang@redhat.com Link: http://lkml.kernel.org/r/20170414122005.o35me2h5nowqkxbv@hirez.programming.kicks-ass.net Signed-off-by: Ingo Molnar --- include/linux/cpumask.h | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) (limited to 'include/linux') diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h index 2404ad238c0b..a21b1fb9a968 100644 --- a/include/linux/cpumask.h +++ b/include/linux/cpumask.h @@ -236,6 +236,23 @@ unsigned int cpumask_local_spread(unsigned int i, int node); (cpu) = cpumask_next_zero((cpu), (mask)), \ (cpu) < nr_cpu_ids;) +extern int cpumask_next_wrap(int n, const struct cpumask *mask, int start, bool wrap); + +/** + * for_each_cpu_wrap - iterate over every cpu in a mask, starting at a specified location + * @cpu: the (optionally unsigned) integer iterator + * @mask: the cpumask poiter + * @start: the start location + * + * The implementation does not assume any bit in @mask is set (including @start). + * + * After the loop, cpu is >= nr_cpu_ids. + */ +#define for_each_cpu_wrap(cpu, mask, start) \ + for ((cpu) = cpumask_next_wrap((start)-1, (mask), (start), false); \ + (cpu) < nr_cpumask_bits; \ + (cpu) = cpumask_next_wrap((cpu), (mask), (start), true)) + /** * for_each_cpu_and - iterate over every cpu in both masks * @cpu: the (optionally unsigned) integer iterator -- cgit v1.2.3 From 6c8557bdb28df3ae97476c5e2aed6373cd235aab Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Fri, 19 May 2017 12:58:25 +0200 Subject: smp, cpumask: Use non-atomic cpumask_{set,clear}_cpu() The cpumasks in smp_call_function_many() are private and not subject to concurrency, atomic bitops are pointless and expensive. Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar --- include/linux/cpumask.h | 11 +++++++++++ 1 file changed, 11 insertions(+) (limited to 'include/linux') diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h index a21b1fb9a968..4bf4479a3a80 100644 --- a/include/linux/cpumask.h +++ b/include/linux/cpumask.h @@ -293,6 +293,12 @@ static inline void cpumask_set_cpu(unsigned int cpu, struct cpumask *dstp) set_bit(cpumask_check(cpu), cpumask_bits(dstp)); } +static inline void __cpumask_set_cpu(unsigned int cpu, struct cpumask *dstp) +{ + __set_bit(cpumask_check(cpu), cpumask_bits(dstp)); +} + + /** * cpumask_clear_cpu - clear a cpu in a cpumask * @cpu: cpu number (< nr_cpu_ids) @@ -303,6 +309,11 @@ static inline void cpumask_clear_cpu(int cpu, struct cpumask *dstp) clear_bit(cpumask_check(cpu), cpumask_bits(dstp)); } +static inline void __cpumask_clear_cpu(int cpu, struct cpumask *dstp) +{ + __clear_bit(cpumask_check(cpu), cpumask_bits(dstp)); +} + /** * cpumask_test_cpu - test for a cpu in a cpumask * @cpu: cpu number (< nr_cpu_ids) -- cgit v1.2.3 From d714893e61cd8c6e5c7e095f7dd615aa434bca95 Mon Sep 17 00:00:00 2001 From: Byungchul Park Date: Fri, 12 May 2017 09:36:56 +0900 Subject: llist: Provide a safe version for llist_for_each() Sometimes we have to dereference next field of llist node before entering loop becasue the node might be deleted or the next field might be modified within the loop. So this adds the safe version of llist_for_each(), that is, llist_for_each_safe(). Signed-off-by: Byungchul Park Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Huang, Ying Cc: Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/1494549416-10539-1-git-send-email-byungchul.park@lge.com Signed-off-by: Ingo Molnar --- include/linux/llist.h | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) (limited to 'include/linux') diff --git a/include/linux/llist.h b/include/linux/llist.h index 171baa90f6f6..d11738110a7a 100644 --- a/include/linux/llist.h +++ b/include/linux/llist.h @@ -109,6 +109,25 @@ static inline void init_llist_head(struct llist_head *list) #define llist_for_each(pos, node) \ for ((pos) = (node); pos; (pos) = (pos)->next) +/** + * llist_for_each_safe - iterate over some deleted entries of a lock-less list + * safe against removal of list entry + * @pos: the &struct llist_node to use as a loop cursor + * @n: another &struct llist_node to use as temporary storage + * @node: the first entry of deleted list entries + * + * In general, some entries of the lock-less list can be traversed + * safely only after being deleted from list, so start with an entry + * instead of list head. + * + * If being used on entries deleted from lock-less list directly, the + * traverse order is from the newest to the oldest added entry. If + * you want to traverse from the oldest to the newest, you must + * reverse the order by yourself before traversing. + */ +#define llist_for_each_safe(pos, n, node) \ + for ((pos) = (node); (pos) && ((n) = (pos)->next, true); (pos) = (n)) + /** * llist_for_each_entry - iterate over some deleted entries of lock-less list of given type * @pos: the type * to use as a loop cursor. -- cgit v1.2.3 From 69a78ff226fe0241ab6cb9dd961667be477e3cf7 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Tue, 16 May 2017 20:42:47 +0200 Subject: init: Introduce SYSTEM_SCHEDULING state might_sleep() debugging and smp_processor_id() debugging should be active right after the scheduler starts working. The init task can invoke smp_processor_id() from preemptible context as it is pinned on the boot cpu until sched_smp_init() removes the pinning and lets it schedule on all non isolated cpus. Add a new state which allows to enable those checks earlier and add it to the xen do_poweroff() function. No functional change. Tested-by: Mark Rutland Signed-off-by: Thomas Gleixner Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Boris Ostrovsky Acked-by: Mark Rutland Cc: Greg Kroah-Hartman Cc: Juergen Gross Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Steven Rostedt Link: http://lkml.kernel.org/r/20170516184736.196214622@linutronix.de Signed-off-by: Ingo Molnar --- include/linux/kernel.h | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'include/linux') diff --git a/include/linux/kernel.h b/include/linux/kernel.h index 13bc08aba704..1c91f26e2996 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -490,9 +490,13 @@ extern int root_mountflags; extern bool early_boot_irqs_disabled; -/* Values used for system_state */ +/* + * Values used for system_state. Ordering of the states must not be changed + * as code checks for <, <=, >, >= STATE. + */ extern enum system_states { SYSTEM_BOOTING, + SYSTEM_SCHEDULING, SYSTEM_RUNNING, SYSTEM_HALT, SYSTEM_POWER_OFF, -- cgit v1.2.3 From 9b01d43170aa70a435105f6413759e2ab7e00219 Mon Sep 17 00:00:00 2001 From: Perr Zhang Date: Fri, 2 Jun 2017 11:59:53 +0800 Subject: sched/header: Remove leftover, obsolete comment There is no more set_task_vxid() helper, remove its description. Signed-off-by: Perr Zhang Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/20170602035953.28949-1-strongbox8@zoho.com Signed-off-by: Ingo Molnar --- include/linux/sched.h | 2 -- 1 file changed, 2 deletions(-) (limited to 'include/linux') diff --git a/include/linux/sched.h b/include/linux/sched.h index 2b69fc650201..1abaa3728bf7 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1096,8 +1096,6 @@ static inline struct pid *task_session(struct task_struct *task) * current. * task_xid_nr_ns() : id seen from the ns specified; * - * set_task_vxid() : assigns a virtual id to a task; - * * see also pid_nr() etc in include/linux/pid.h */ pid_t __task_pid_nr_ns(struct task_struct *task, enum pid_type type, struct pid_namespace *ns); -- cgit v1.2.3 From 209a0cbda7a01d2ea32a8b631d35e873bee498e9 Mon Sep 17 00:00:00 2001 From: Luca Abeni Date: Thu, 18 May 2017 22:13:29 +0200 Subject: sched/deadline: Improve the tracking of active utilization This patch implements a more theoretically sound algorithm for tracking active utilization: instead of decreasing it when a task blocks, use a timer (the "inactive timer", named after the "Inactive" task state of the GRUB algorithm) to decrease the active utilization at the so called "0-lag time". Tested-by: Claudio Scordino Tested-by: Daniel Bristot de Oliveira Signed-off-by: Luca Abeni Signed-off-by: Peter Zijlstra (Intel) Cc: Joel Fernandes Cc: Juri Lelli Cc: Linus Torvalds Cc: Mathieu Poirier Cc: Mike Galbraith Cc: Peter Zijlstra Cc: Steven Rostedt Cc: Thomas Gleixner Cc: Tommaso Cucinotta Link: http://lkml.kernel.org/r/1495138417-6203-3-git-send-email-luca.abeni@santannapisa.it Signed-off-by: Ingo Molnar --- include/linux/sched.h | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) (limited to 'include/linux') diff --git a/include/linux/sched.h b/include/linux/sched.h index 1abaa3728bf7..f1ead2e88d3d 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -445,16 +445,33 @@ struct sched_dl_entity { * * @dl_yielded tells if task gave up the CPU before consuming * all its available runtime during the last job. + * + * @dl_non_contending tells if the task is inactive while still + * contributing to the active utilization. In other words, it + * indicates if the inactive timer has been armed and its handler + * has not been executed yet. This flag is useful to avoid race + * conditions between the inactive timer handler and the wakeup + * code. */ int dl_throttled; int dl_boosted; int dl_yielded; + int dl_non_contending; /* * Bandwidth enforcement timer. Each -deadline task has its * own bandwidth to be enforced, thus we need one timer per task. */ struct hrtimer dl_timer; + + /* + * Inactive timer, responsible for decreasing the active utilization + * at the "0-lag time". When a -deadline task blocks, it contributes + * to GRUB's active utilization until the "0-lag time", hence a + * timer is needed to decrease the active utilization at the correct + * time. + */ + struct hrtimer inactive_timer; }; union rcu_special { -- cgit v1.2.3 From 54d6d3039e2d84b6fbfbe59ec57d856371edf0a2 Mon Sep 17 00:00:00 2001 From: Daniel Bristot de Oliveira Date: Mon, 29 May 2017 16:24:02 +0200 Subject: sched/deadline: Fix dl_bw comment The sched_dl_entity's dl_bw variable stores the utilization (dl_runtime / dl_period) of a task, not its density (dl_runtime / dl_deadline), as the comment says. Signed-off-by: Daniel Bristot de Oliveira Signed-off-by: Peter Zijlstra (Intel) Cc: Juri Lelli Cc: Linus Torvalds Cc: Luca Abeni Cc: Mike Galbraith Cc: Peter Zijlstra Cc: Romulo Silva de Oliveira Cc: Steven Rostedt Cc: Thomas Gleixner Cc: Tommaso Cucinotta Cc: Xunlei Pang Link: http://lkml.kernel.org/r/8d05f1ccfd02da1a11bda62494d98f5456c1469a.1495803804.git.bristot@redhat.com Signed-off-by: Ingo Molnar --- include/linux/sched.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/linux') diff --git a/include/linux/sched.h b/include/linux/sched.h index f1ead2e88d3d..3113c828483b 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -421,7 +421,7 @@ struct sched_dl_entity { u64 dl_runtime; /* Maximum runtime for each instance */ u64 dl_deadline; /* Relative deadline of each instance */ u64 dl_period; /* Separation of two instances (period) */ - u64 dl_bw; /* dl_runtime / dl_deadline */ + u64 dl_bw; /* dl_runtime / dl_period */ /* * Actual scheduling parameters. Initialized with the values above, -- cgit v1.2.3 From 3effcb4247e74a51f5d8b775a1ee4abf87cc089a Mon Sep 17 00:00:00 2001 From: Daniel Bristot de Oliveira Date: Mon, 29 May 2017 16:24:03 +0200 Subject: sched/deadline: Use the revised wakeup rule for suspending constrained dl tasks We have been facing some problems with self-suspending constrained deadline tasks. The main reason is that the original CBS was not designed for such sort of tasks. One problem reported by Xunlei Pang takes place when a task suspends, and then is awakened before the deadline, but so close to the deadline that its remaining runtime can cause the task to have an absolute density higher than allowed. In such situation, the original CBS assumes that the task is facing an early activation, and so it replenishes the task and set another deadline, one deadline in the future. This rule works fine for implicit deadline tasks. Moreover, it allows the system to adapt the period of a task in which the external event source suffered from a clock drift. However, this opens the window for bandwidth leakage for constrained deadline tasks. For instance, a task with the following parameters: runtime = 5 ms deadline = 7 ms [density] = 5 / 7 = 0.71 period = 1000 ms If the task runs for 1 ms, and then suspends for another 1ms, it will be awakened with the following parameters: remaining runtime = 4 laxity = 5 presenting a absolute density of 4 / 5 = 0.80. In this case, the original CBS would assume the task had an early wakeup. Then, CBS will reset the runtime, and the absolute deadline will be postponed by one relative deadline, allowing the task to run. The problem is that, if the task runs this pattern forever, it will keep receiving bandwidth, being able to run 1ms every 2ms. Following this behavior, the task would be able to run 500 ms in 1 sec. Thus running more than the 5 ms / 1 sec the admission control allowed it to run. Trying to address the self-suspending case, Luca Abeni, Giuseppe Lipari, and Juri Lelli [1] revisited the CBS in order to deal with self-suspending tasks. In the new approach, rather than replenishing/postponing the absolute deadline, the revised wakeup rule adjusts the remaining runtime, reducing it to fit into the allowed density. A revised version of the idea is: At a given time t, the maximum absolute density of a task cannot be higher than its relative density, that is: runtime / (deadline - t) <= dl_runtime / dl_deadline Knowing the laxity of a task (deadline - t), it is possible to move it to the other side of the equality, thus enabling to define max remaining runtime a task can use within the absolute deadline, without over-running the allowed density: runtime = (dl_runtime / dl_deadline) * (deadline - t) For instance, in our previous example, the task could still run: runtime = ( 5 / 7 ) * 5 runtime = 3.57 ms Without causing damage for other deadline tasks. It is note worthy that the laxity cannot be negative because that would cause a negative runtime. Thus, this patch depends on the patch: df8eac8cafce ("sched/deadline: Throttle a constrained deadline task activated after the deadline") Which throttles a constrained deadline task activated after the deadline. Finally, it is also possible to use the revised wakeup rule for all other tasks, but that would require some more discussions about pros and cons. Reported-by: Xunlei Pang Signed-off-by: Daniel Bristot de Oliveira [peterz: replaced dl_is_constrained with dl_is_implicit] Signed-off-by: Peter Zijlstra (Intel) Cc: Juri Lelli Cc: Linus Torvalds Cc: Luca Abeni Cc: Mike Galbraith Cc: Peter Zijlstra Cc: Romulo Silva de Oliveira Cc: Steven Rostedt Cc: Thomas Gleixner Cc: Tommaso Cucinotta Link: http://lkml.kernel.org/r/5c800ab3a74a168a84ee5f3f84d12a02e11383be.1495803804.git.bristot@redhat.com Signed-off-by: Ingo Molnar --- include/linux/sched.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux') diff --git a/include/linux/sched.h b/include/linux/sched.h index 3113c828483b..1f0f427e0292 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -422,6 +422,7 @@ struct sched_dl_entity { u64 dl_deadline; /* Relative deadline of each instance */ u64 dl_period; /* Separation of two instances (period) */ u64 dl_bw; /* dl_runtime / dl_period */ + u64 dl_density; /* dl_runtime / dl_deadline */ /* * Actual scheduling parameters. Initialized with the values above, -- cgit v1.2.3 From ac6424b981bce1c4bc55675c6ce11bfe1bbfa64f Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Tue, 20 Jun 2017 12:06:13 +0200 Subject: sched/wait: Rename wait_queue_t => wait_queue_entry_t Rename: wait_queue_t => wait_queue_entry_t 'wait_queue_t' was always a slight misnomer: its name implies that it's a "queue", but in reality it's a queue *entry*. The 'real' queue is the wait queue head, which had to carry the name. Start sorting this out by renaming it to 'wait_queue_entry_t'. This also allows the real structure name 'struct __wait_queue' to lose its double underscore and become 'struct wait_queue_entry', which is the more canonical nomenclature for such data types. Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar --- include/linux/blk-mq.h | 2 +- include/linux/eventfd.h | 4 +-- include/linux/kvm_irqfd.h | 2 +- include/linux/pagemap.h | 2 +- include/linux/poll.h | 2 +- include/linux/vfio.h | 2 +- include/linux/wait.h | 67 +++++++++++++++++++++++++---------------------- 7 files changed, 42 insertions(+), 39 deletions(-) (limited to 'include/linux') diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h index fcd641032f8d..95ba83806c5d 100644 --- a/include/linux/blk-mq.h +++ b/include/linux/blk-mq.h @@ -33,7 +33,7 @@ struct blk_mq_hw_ctx { struct blk_mq_ctx **ctxs; unsigned int nr_ctx; - wait_queue_t dispatch_wait; + wait_queue_entry_t dispatch_wait; atomic_t wait_index; struct blk_mq_tags *tags; diff --git a/include/linux/eventfd.h b/include/linux/eventfd.h index ff0b981f078e..9e4befd95bc7 100644 --- a/include/linux/eventfd.h +++ b/include/linux/eventfd.h @@ -37,7 +37,7 @@ struct eventfd_ctx *eventfd_ctx_fdget(int fd); struct eventfd_ctx *eventfd_ctx_fileget(struct file *file); __u64 eventfd_signal(struct eventfd_ctx *ctx, __u64 n); ssize_t eventfd_ctx_read(struct eventfd_ctx *ctx, int no_wait, __u64 *cnt); -int eventfd_ctx_remove_wait_queue(struct eventfd_ctx *ctx, wait_queue_t *wait, +int eventfd_ctx_remove_wait_queue(struct eventfd_ctx *ctx, wait_queue_entry_t *wait, __u64 *cnt); #else /* CONFIG_EVENTFD */ @@ -73,7 +73,7 @@ static inline ssize_t eventfd_ctx_read(struct eventfd_ctx *ctx, int no_wait, } static inline int eventfd_ctx_remove_wait_queue(struct eventfd_ctx *ctx, - wait_queue_t *wait, __u64 *cnt) + wait_queue_entry_t *wait, __u64 *cnt) { return -ENOSYS; } diff --git a/include/linux/kvm_irqfd.h b/include/linux/kvm_irqfd.h index 0c1de05098c8..76c2fbc59f35 100644 --- a/include/linux/kvm_irqfd.h +++ b/include/linux/kvm_irqfd.h @@ -46,7 +46,7 @@ struct kvm_kernel_irqfd_resampler { struct kvm_kernel_irqfd { /* Used for MSI fast-path */ struct kvm *kvm; - wait_queue_t wait; + wait_queue_entry_t wait; /* Update side is protected by irqfds.lock */ struct kvm_kernel_irq_routing_entry irq_entry; seqcount_t irq_entry_sc; diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h index 316a19f6b635..e7bbd9d4dc6c 100644 --- a/include/linux/pagemap.h +++ b/include/linux/pagemap.h @@ -524,7 +524,7 @@ void page_endio(struct page *page, bool is_write, int err); /* * Add an arbitrary waiter to a page's wait queue */ -extern void add_page_wait_queue(struct page *page, wait_queue_t *waiter); +extern void add_page_wait_queue(struct page *page, wait_queue_entry_t *waiter); /* * Fault everything in given userspace address range in. diff --git a/include/linux/poll.h b/include/linux/poll.h index 75ffc5729e4c..2889f09a1c60 100644 --- a/include/linux/poll.h +++ b/include/linux/poll.h @@ -75,7 +75,7 @@ static inline void init_poll_funcptr(poll_table *pt, poll_queue_proc qproc) struct poll_table_entry { struct file *filp; unsigned long key; - wait_queue_t wait; + wait_queue_entry_t wait; wait_queue_head_t *wait_address; }; diff --git a/include/linux/vfio.h b/include/linux/vfio.h index edf9b2cad277..f57076b958b7 100644 --- a/include/linux/vfio.h +++ b/include/linux/vfio.h @@ -183,7 +183,7 @@ struct virqfd { void (*thread)(void *, void *); void *data; struct work_struct inject; - wait_queue_t wait; + wait_queue_entry_t wait; poll_table pt; struct work_struct shutdown; struct virqfd **pvirqfd; diff --git a/include/linux/wait.h b/include/linux/wait.h index db076ca7f11d..5889f0c86ff7 100644 --- a/include/linux/wait.h +++ b/include/linux/wait.h @@ -10,15 +10,18 @@ #include #include -typedef struct __wait_queue wait_queue_t; -typedef int (*wait_queue_func_t)(wait_queue_t *wait, unsigned mode, int flags, void *key); -int default_wake_function(wait_queue_t *wait, unsigned mode, int flags, void *key); +typedef struct wait_queue_entry wait_queue_entry_t; +typedef int (*wait_queue_func_t)(wait_queue_entry_t *wait, unsigned mode, int flags, void *key); +int default_wake_function(wait_queue_entry_t *wait, unsigned mode, int flags, void *key); -/* __wait_queue::flags */ +/* wait_queue_entry::flags */ #define WQ_FLAG_EXCLUSIVE 0x01 #define WQ_FLAG_WOKEN 0x02 -struct __wait_queue { +/* + * A single wait-queue entry structure: + */ +struct wait_queue_entry { unsigned int flags; void *private; wait_queue_func_t func; @@ -34,7 +37,7 @@ struct wait_bit_key { struct wait_bit_queue { struct wait_bit_key key; - wait_queue_t wait; + wait_queue_entry_t wait; }; struct __wait_queue_head { @@ -55,7 +58,7 @@ struct task_struct; .task_list = { NULL, NULL } } #define DECLARE_WAITQUEUE(name, tsk) \ - wait_queue_t name = __WAITQUEUE_INITIALIZER(name, tsk) + wait_queue_entry_t name = __WAITQUEUE_INITIALIZER(name, tsk) #define __WAIT_QUEUE_HEAD_INITIALIZER(name) { \ .lock = __SPIN_LOCK_UNLOCKED(name.lock), \ @@ -88,7 +91,7 @@ extern void __init_waitqueue_head(wait_queue_head_t *q, const char *name, struct # define DECLARE_WAIT_QUEUE_HEAD_ONSTACK(name) DECLARE_WAIT_QUEUE_HEAD(name) #endif -static inline void init_waitqueue_entry(wait_queue_t *q, struct task_struct *p) +static inline void init_waitqueue_entry(wait_queue_entry_t *q, struct task_struct *p) { q->flags = 0; q->private = p; @@ -96,7 +99,7 @@ static inline void init_waitqueue_entry(wait_queue_t *q, struct task_struct *p) } static inline void -init_waitqueue_func_entry(wait_queue_t *q, wait_queue_func_t func) +init_waitqueue_func_entry(wait_queue_entry_t *q, wait_queue_func_t func) { q->flags = 0; q->private = NULL; @@ -159,11 +162,11 @@ static inline bool wq_has_sleeper(wait_queue_head_t *wq) return waitqueue_active(wq); } -extern void add_wait_queue(wait_queue_head_t *q, wait_queue_t *wait); -extern void add_wait_queue_exclusive(wait_queue_head_t *q, wait_queue_t *wait); -extern void remove_wait_queue(wait_queue_head_t *q, wait_queue_t *wait); +extern void add_wait_queue(wait_queue_head_t *q, wait_queue_entry_t *wait); +extern void add_wait_queue_exclusive(wait_queue_head_t *q, wait_queue_entry_t *wait); +extern void remove_wait_queue(wait_queue_head_t *q, wait_queue_entry_t *wait); -static inline void __add_wait_queue(wait_queue_head_t *head, wait_queue_t *new) +static inline void __add_wait_queue(wait_queue_head_t *head, wait_queue_entry_t *new) { list_add(&new->task_list, &head->task_list); } @@ -172,27 +175,27 @@ static inline void __add_wait_queue(wait_queue_head_t *head, wait_queue_t *new) * Used for wake-one threads: */ static inline void -__add_wait_queue_exclusive(wait_queue_head_t *q, wait_queue_t *wait) +__add_wait_queue_exclusive(wait_queue_head_t *q, wait_queue_entry_t *wait) { wait->flags |= WQ_FLAG_EXCLUSIVE; __add_wait_queue(q, wait); } -static inline void __add_wait_queue_tail(wait_queue_head_t *head, - wait_queue_t *new) +static inline void __add_wait_queue_entry_tail(wait_queue_head_t *head, + wait_queue_entry_t *new) { list_add_tail(&new->task_list, &head->task_list); } static inline void -__add_wait_queue_tail_exclusive(wait_queue_head_t *q, wait_queue_t *wait) +__add_wait_queue_entry_tail_exclusive(wait_queue_head_t *q, wait_queue_entry_t *wait) { wait->flags |= WQ_FLAG_EXCLUSIVE; - __add_wait_queue_tail(q, wait); + __add_wait_queue_entry_tail(q, wait); } static inline void -__remove_wait_queue(wait_queue_head_t *head, wait_queue_t *old) +__remove_wait_queue(wait_queue_head_t *head, wait_queue_entry_t *old) { list_del(&old->task_list); } @@ -249,7 +252,7 @@ wait_queue_head_t *bit_waitqueue(void *, int); (!__builtin_constant_p(state) || \ state == TASK_INTERRUPTIBLE || state == TASK_KILLABLE) \ -extern void init_wait_entry(wait_queue_t *__wait, int flags); +extern void init_wait_entry(wait_queue_entry_t *__wait, int flags); /* * The below macro ___wait_event() has an explicit shadow of the __ret @@ -266,7 +269,7 @@ extern void init_wait_entry(wait_queue_t *__wait, int flags); #define ___wait_event(wq, condition, state, exclusive, ret, cmd) \ ({ \ __label__ __out; \ - wait_queue_t __wait; \ + wait_queue_entry_t __wait; \ long __ret = ret; /* explicit shadow */ \ \ init_wait_entry(&__wait, exclusive ? WQ_FLAG_EXCLUSIVE : 0); \ @@ -620,8 +623,8 @@ do { \ __ret; \ }) -extern int do_wait_intr(wait_queue_head_t *, wait_queue_t *); -extern int do_wait_intr_irq(wait_queue_head_t *, wait_queue_t *); +extern int do_wait_intr(wait_queue_head_t *, wait_queue_entry_t *); +extern int do_wait_intr_irq(wait_queue_head_t *, wait_queue_entry_t *); #define __wait_event_interruptible_locked(wq, condition, exclusive, fn) \ ({ \ @@ -967,17 +970,17 @@ do { \ /* * Waitqueues which are removed from the waitqueue_head at wakeup time */ -void prepare_to_wait(wait_queue_head_t *q, wait_queue_t *wait, int state); -void prepare_to_wait_exclusive(wait_queue_head_t *q, wait_queue_t *wait, int state); -long prepare_to_wait_event(wait_queue_head_t *q, wait_queue_t *wait, int state); -void finish_wait(wait_queue_head_t *q, wait_queue_t *wait); -long wait_woken(wait_queue_t *wait, unsigned mode, long timeout); -int woken_wake_function(wait_queue_t *wait, unsigned mode, int sync, void *key); -int autoremove_wake_function(wait_queue_t *wait, unsigned mode, int sync, void *key); -int wake_bit_function(wait_queue_t *wait, unsigned mode, int sync, void *key); +void prepare_to_wait(wait_queue_head_t *q, wait_queue_entry_t *wait, int state); +void prepare_to_wait_exclusive(wait_queue_head_t *q, wait_queue_entry_t *wait, int state); +long prepare_to_wait_event(wait_queue_head_t *q, wait_queue_entry_t *wait, int state); +void finish_wait(wait_queue_head_t *q, wait_queue_entry_t *wait); +long wait_woken(wait_queue_entry_t *wait, unsigned mode, long timeout); +int woken_wake_function(wait_queue_entry_t *wait, unsigned mode, int sync, void *key); +int autoremove_wake_function(wait_queue_entry_t *wait, unsigned mode, int sync, void *key); +int wake_bit_function(wait_queue_entry_t *wait, unsigned mode, int sync, void *key); #define DEFINE_WAIT_FUNC(name, function) \ - wait_queue_t name = { \ + wait_queue_entry_t name = { \ .private = current, \ .func = function, \ .task_list = LIST_HEAD_INIT((name).task_list), \ -- cgit v1.2.3 From 50816c48997af857d4bab3dca1aba90339705e96 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Sun, 5 Mar 2017 10:33:16 +0100 Subject: sched/wait: Standardize internal naming of wait-queue entries So the various wait-queue entry variables in include/linux/wait.h and kernel/sched/wait.c are named in a colorfully inconsistent way: wait_queue_entry_t *wait wait_queue_entry_t *__wait (even in plain C code!) wait_queue_entry_t *q (!) wait_queue_entry_t *new (making anyone who knows C++ cringe) wait_queue_entry_t *old I think part of the reason for the inconsistency is the constant apparent confusion about what a wait queue 'head' versus 'entry' is. ( Some of the documentation talks about a 'wait descriptor', which is the wait-queue entry itself - further adding to the confusion. ) The most common name is 'wait', but that in itself is somewhat ambiguous as well, as it does not really make it clear whether it's a wait-queue entry or head. To improve all this name the wait-queue entry structure parameters and variables consistently and push through this naming into all the wait.h and wait.c code: struct wait_queue_entry *wq_entry The 'wq_' prefix makes it easy to grep for, and we also use the opportunity to move away from the typedef to a plain 'struct' naming: in the kernel we typically reserve typedefs for cases where a C structure is really small and somewhat opaque - such as pte_t. wait-queue entries are neither small nor opaque, so use the more standard 'struct xxx_entry' list management code nomenclature instead. ( We don't touch external users, and we preserve the typedef as well for actual wait-queue users, to reduce unnecessary churn. ) Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar --- include/linux/wait.h | 84 ++++++++++++++++++++++++++-------------------------- 1 file changed, 42 insertions(+), 42 deletions(-) (limited to 'include/linux') diff --git a/include/linux/wait.h b/include/linux/wait.h index 5889f0c86ff7..77fdea851d8b 100644 --- a/include/linux/wait.h +++ b/include/linux/wait.h @@ -11,8 +11,9 @@ #include typedef struct wait_queue_entry wait_queue_entry_t; -typedef int (*wait_queue_func_t)(wait_queue_entry_t *wait, unsigned mode, int flags, void *key); -int default_wake_function(wait_queue_entry_t *wait, unsigned mode, int flags, void *key); + +typedef int (*wait_queue_func_t)(struct wait_queue_entry *wq_entry, unsigned mode, int flags, void *key); +int default_wake_function(struct wait_queue_entry *wq_entry, unsigned mode, int flags, void *key); /* wait_queue_entry::flags */ #define WQ_FLAG_EXCLUSIVE 0x01 @@ -37,7 +38,7 @@ struct wait_bit_key { struct wait_bit_queue { struct wait_bit_key key; - wait_queue_entry_t wait; + struct wait_queue_entry wait; }; struct __wait_queue_head { @@ -58,7 +59,7 @@ struct task_struct; .task_list = { NULL, NULL } } #define DECLARE_WAITQUEUE(name, tsk) \ - wait_queue_entry_t name = __WAITQUEUE_INITIALIZER(name, tsk) + struct wait_queue_entry name = __WAITQUEUE_INITIALIZER(name, tsk) #define __WAIT_QUEUE_HEAD_INITIALIZER(name) { \ .lock = __SPIN_LOCK_UNLOCKED(name.lock), \ @@ -91,19 +92,19 @@ extern void __init_waitqueue_head(wait_queue_head_t *q, const char *name, struct # define DECLARE_WAIT_QUEUE_HEAD_ONSTACK(name) DECLARE_WAIT_QUEUE_HEAD(name) #endif -static inline void init_waitqueue_entry(wait_queue_entry_t *q, struct task_struct *p) +static inline void init_waitqueue_entry(struct wait_queue_entry *wq_entry, struct task_struct *p) { - q->flags = 0; - q->private = p; - q->func = default_wake_function; + wq_entry->flags = 0; + wq_entry->private = p; + wq_entry->func = default_wake_function; } static inline void -init_waitqueue_func_entry(wait_queue_entry_t *q, wait_queue_func_t func) +init_waitqueue_func_entry(struct wait_queue_entry *wq_entry, wait_queue_func_t func) { - q->flags = 0; - q->private = NULL; - q->func = func; + wq_entry->flags = 0; + wq_entry->private = NULL; + wq_entry->func = func; } /** @@ -162,42 +163,41 @@ static inline bool wq_has_sleeper(wait_queue_head_t *wq) return waitqueue_active(wq); } -extern void add_wait_queue(wait_queue_head_t *q, wait_queue_entry_t *wait); -extern void add_wait_queue_exclusive(wait_queue_head_t *q, wait_queue_entry_t *wait); -extern void remove_wait_queue(wait_queue_head_t *q, wait_queue_entry_t *wait); +extern void add_wait_queue(wait_queue_head_t *q, struct wait_queue_entry *wq_entry); +extern void add_wait_queue_exclusive(wait_queue_head_t *q, struct wait_queue_entry *wq_entry); +extern void remove_wait_queue(wait_queue_head_t *q, struct wait_queue_entry *wq_entry); -static inline void __add_wait_queue(wait_queue_head_t *head, wait_queue_entry_t *new) +static inline void __add_wait_queue(wait_queue_head_t *head, struct wait_queue_entry *wq_entry) { - list_add(&new->task_list, &head->task_list); + list_add(&wq_entry->task_list, &head->task_list); } /* * Used for wake-one threads: */ static inline void -__add_wait_queue_exclusive(wait_queue_head_t *q, wait_queue_entry_t *wait) +__add_wait_queue_exclusive(wait_queue_head_t *q, struct wait_queue_entry *wq_entry) { - wait->flags |= WQ_FLAG_EXCLUSIVE; - __add_wait_queue(q, wait); + wq_entry->flags |= WQ_FLAG_EXCLUSIVE; + __add_wait_queue(q, wq_entry); } -static inline void __add_wait_queue_entry_tail(wait_queue_head_t *head, - wait_queue_entry_t *new) +static inline void __add_wait_queue_entry_tail(wait_queue_head_t *head, struct wait_queue_entry *wq_entry) { - list_add_tail(&new->task_list, &head->task_list); + list_add_tail(&wq_entry->task_list, &head->task_list); } static inline void -__add_wait_queue_entry_tail_exclusive(wait_queue_head_t *q, wait_queue_entry_t *wait) +__add_wait_queue_entry_tail_exclusive(wait_queue_head_t *q, struct wait_queue_entry *wq_entry) { - wait->flags |= WQ_FLAG_EXCLUSIVE; - __add_wait_queue_entry_tail(q, wait); + wq_entry->flags |= WQ_FLAG_EXCLUSIVE; + __add_wait_queue_entry_tail(q, wq_entry); } static inline void -__remove_wait_queue(wait_queue_head_t *head, wait_queue_entry_t *old) +__remove_wait_queue(wait_queue_head_t *head, struct wait_queue_entry *wq_entry) { - list_del(&old->task_list); + list_del(&wq_entry->task_list); } typedef int wait_bit_action_f(struct wait_bit_key *, int mode); @@ -252,7 +252,7 @@ wait_queue_head_t *bit_waitqueue(void *, int); (!__builtin_constant_p(state) || \ state == TASK_INTERRUPTIBLE || state == TASK_KILLABLE) \ -extern void init_wait_entry(wait_queue_entry_t *__wait, int flags); +extern void init_wait_entry(struct wait_queue_entry *wq_entry, int flags); /* * The below macro ___wait_event() has an explicit shadow of the __ret @@ -269,12 +269,12 @@ extern void init_wait_entry(wait_queue_entry_t *__wait, int flags); #define ___wait_event(wq, condition, state, exclusive, ret, cmd) \ ({ \ __label__ __out; \ - wait_queue_entry_t __wait; \ + struct wait_queue_entry __wq_entry; \ long __ret = ret; /* explicit shadow */ \ \ - init_wait_entry(&__wait, exclusive ? WQ_FLAG_EXCLUSIVE : 0); \ + init_wait_entry(&__wq_entry, exclusive ? WQ_FLAG_EXCLUSIVE : 0);\ for (;;) { \ - long __int = prepare_to_wait_event(&wq, &__wait, state);\ + long __int = prepare_to_wait_event(&wq, &__wq_entry, state);\ \ if (condition) \ break; \ @@ -286,7 +286,7 @@ extern void init_wait_entry(wait_queue_entry_t *__wait, int flags); \ cmd; \ } \ - finish_wait(&wq, &__wait); \ + finish_wait(&wq, &__wq_entry); \ __out: __ret; \ }) @@ -970,17 +970,17 @@ do { \ /* * Waitqueues which are removed from the waitqueue_head at wakeup time */ -void prepare_to_wait(wait_queue_head_t *q, wait_queue_entry_t *wait, int state); -void prepare_to_wait_exclusive(wait_queue_head_t *q, wait_queue_entry_t *wait, int state); -long prepare_to_wait_event(wait_queue_head_t *q, wait_queue_entry_t *wait, int state); -void finish_wait(wait_queue_head_t *q, wait_queue_entry_t *wait); -long wait_woken(wait_queue_entry_t *wait, unsigned mode, long timeout); -int woken_wake_function(wait_queue_entry_t *wait, unsigned mode, int sync, void *key); -int autoremove_wake_function(wait_queue_entry_t *wait, unsigned mode, int sync, void *key); -int wake_bit_function(wait_queue_entry_t *wait, unsigned mode, int sync, void *key); +void prepare_to_wait(wait_queue_head_t *q, struct wait_queue_entry *wq_entry, int state); +void prepare_to_wait_exclusive(wait_queue_head_t *q, struct wait_queue_entry *wq_entry, int state); +long prepare_to_wait_event(wait_queue_head_t *q, struct wait_queue_entry *wq_entry, int state); +void finish_wait(wait_queue_head_t *q, struct wait_queue_entry *wq_entry); +long wait_woken(struct wait_queue_entry *wq_entry, unsigned mode, long timeout); +int woken_wake_function(struct wait_queue_entry *wq_entry, unsigned mode, int sync, void *key); +int autoremove_wake_function(struct wait_queue_entry *wq_entry, unsigned mode, int sync, void *key); +int wake_bit_function(struct wait_queue_entry *wq_entry, unsigned mode, int sync, void *key); #define DEFINE_WAIT_FUNC(name, function) \ - wait_queue_entry_t name = { \ + struct wait_queue_entry name = { \ .private = current, \ .func = function, \ .task_list = LIST_HEAD_INIT((name).task_list), \ -- cgit v1.2.3 From 9d9d676f595b5081326be7a17dc681fcb38fb3b2 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Sun, 5 Mar 2017 11:10:18 +0100 Subject: sched/wait: Standardize internal naming of wait-queue heads The wait-queue head parameters and variables are named in a couple of ways, we have the following variants currently: wait_queue_head_t *q wait_queue_head_t *wq wait_queue_head_t *head In particular the 'wq' naming is ambiguous in the sense whether it's a wait-queue head or entry name - as entries were often named 'wait'. ( Not to mention the confusion of any readers coming over from workqueue-land. ) Standardize all this around a single, unambiguous parameter and variable name: struct wait_queue_head *wq_head which is easy to grep for and also rhymes nicely with the wait-queue entry naming: struct wait_queue_entry *wq_entry Also rename: struct __wait_queue_head => struct wait_queue_head ... and use this struct type to migrate from typedefs usage to 'struct' usage, which is more in line with existing kernel practices. Don't touch any external users and preserve the main wait_queue_head_t typedef. Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar --- include/linux/wait.h | 76 ++++++++++++++++++++++++++-------------------------- 1 file changed, 38 insertions(+), 38 deletions(-) (limited to 'include/linux') diff --git a/include/linux/wait.h b/include/linux/wait.h index 77fdea851d8b..c3d1cefc7853 100644 --- a/include/linux/wait.h +++ b/include/linux/wait.h @@ -41,11 +41,11 @@ struct wait_bit_queue { struct wait_queue_entry wait; }; -struct __wait_queue_head { +struct wait_queue_head { spinlock_t lock; struct list_head task_list; }; -typedef struct __wait_queue_head wait_queue_head_t; +typedef struct wait_queue_head wait_queue_head_t; struct task_struct; @@ -66,7 +66,7 @@ struct task_struct; .task_list = { &(name).task_list, &(name).task_list } } #define DECLARE_WAIT_QUEUE_HEAD(name) \ - wait_queue_head_t name = __WAIT_QUEUE_HEAD_INITIALIZER(name) + struct wait_queue_head name = __WAIT_QUEUE_HEAD_INITIALIZER(name) #define __WAIT_BIT_KEY_INITIALIZER(word, bit) \ { .flags = word, .bit_nr = bit, } @@ -74,20 +74,20 @@ struct task_struct; #define __WAIT_ATOMIC_T_KEY_INITIALIZER(p) \ { .flags = p, .bit_nr = WAIT_ATOMIC_T_BIT_NR, } -extern void __init_waitqueue_head(wait_queue_head_t *q, const char *name, struct lock_class_key *); +extern void __init_waitqueue_head(struct wait_queue_head *wq_head, const char *name, struct lock_class_key *); -#define init_waitqueue_head(q) \ +#define init_waitqueue_head(wq_head) \ do { \ static struct lock_class_key __key; \ \ - __init_waitqueue_head((q), #q, &__key); \ + __init_waitqueue_head((wq_head), #wq_head, &__key); \ } while (0) #ifdef CONFIG_LOCKDEP # define __WAIT_QUEUE_HEAD_INIT_ONSTACK(name) \ ({ init_waitqueue_head(&name); name; }) # define DECLARE_WAIT_QUEUE_HEAD_ONSTACK(name) \ - wait_queue_head_t name = __WAIT_QUEUE_HEAD_INIT_ONSTACK(name) + struct wait_queue_head name = __WAIT_QUEUE_HEAD_INIT_ONSTACK(name) #else # define DECLARE_WAIT_QUEUE_HEAD_ONSTACK(name) DECLARE_WAIT_QUEUE_HEAD(name) #endif @@ -109,14 +109,14 @@ init_waitqueue_func_entry(struct wait_queue_entry *wq_entry, wait_queue_func_t f /** * waitqueue_active -- locklessly test for waiters on the queue - * @q: the waitqueue to test for waiters + * @wq_head: the waitqueue to test for waiters * * returns true if the wait list is not empty * * NOTE: this function is lockless and requires care, incorrect usage _will_ * lead to sporadic and non-obvious failure. * - * Use either while holding wait_queue_head_t::lock or when used for wakeups + * Use either while holding wait_queue_head::lock or when used for wakeups * with an extra smp_mb() like: * * CPU0 - waker CPU1 - waiter @@ -137,9 +137,9 @@ init_waitqueue_func_entry(struct wait_queue_entry *wq_entry, wait_queue_func_t f * Also note that this 'optimization' trades a spin_lock() for an smp_mb(), * which (when the lock is uncontended) are of roughly equal cost. */ -static inline int waitqueue_active(wait_queue_head_t *q) +static inline int waitqueue_active(struct wait_queue_head *wq_head) { - return !list_empty(&q->task_list); + return !list_empty(&wq_head->task_list); } /** @@ -150,7 +150,7 @@ static inline int waitqueue_active(wait_queue_head_t *q) * * Please refer to the comment for waitqueue_active. */ -static inline bool wq_has_sleeper(wait_queue_head_t *wq) +static inline bool wq_has_sleeper(struct wait_queue_head *wq_head) { /* * We need to be sure we are in sync with the @@ -160,62 +160,62 @@ static inline bool wq_has_sleeper(wait_queue_head_t *wq) * waiting side. */ smp_mb(); - return waitqueue_active(wq); + return waitqueue_active(wq_head); } -extern void add_wait_queue(wait_queue_head_t *q, struct wait_queue_entry *wq_entry); -extern void add_wait_queue_exclusive(wait_queue_head_t *q, struct wait_queue_entry *wq_entry); -extern void remove_wait_queue(wait_queue_head_t *q, struct wait_queue_entry *wq_entry); +extern void add_wait_queue(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry); +extern void add_wait_queue_exclusive(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry); +extern void remove_wait_queue(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry); -static inline void __add_wait_queue(wait_queue_head_t *head, struct wait_queue_entry *wq_entry) +static inline void __add_wait_queue(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry) { - list_add(&wq_entry->task_list, &head->task_list); + list_add(&wq_entry->task_list, &wq_head->task_list); } /* * Used for wake-one threads: */ static inline void -__add_wait_queue_exclusive(wait_queue_head_t *q, struct wait_queue_entry *wq_entry) +__add_wait_queue_exclusive(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry) { wq_entry->flags |= WQ_FLAG_EXCLUSIVE; - __add_wait_queue(q, wq_entry); + __add_wait_queue(wq_head, wq_entry); } -static inline void __add_wait_queue_entry_tail(wait_queue_head_t *head, struct wait_queue_entry *wq_entry) +static inline void __add_wait_queue_entry_tail(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry) { - list_add_tail(&wq_entry->task_list, &head->task_list); + list_add_tail(&wq_entry->task_list, &wq_head->task_list); } static inline void -__add_wait_queue_entry_tail_exclusive(wait_queue_head_t *q, struct wait_queue_entry *wq_entry) +__add_wait_queue_entry_tail_exclusive(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry) { wq_entry->flags |= WQ_FLAG_EXCLUSIVE; - __add_wait_queue_entry_tail(q, wq_entry); + __add_wait_queue_entry_tail(wq_head, wq_entry); } static inline void -__remove_wait_queue(wait_queue_head_t *head, struct wait_queue_entry *wq_entry) +__remove_wait_queue(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry) { list_del(&wq_entry->task_list); } typedef int wait_bit_action_f(struct wait_bit_key *, int mode); -void __wake_up(wait_queue_head_t *q, unsigned int mode, int nr, void *key); -void __wake_up_locked_key(wait_queue_head_t *q, unsigned int mode, void *key); -void __wake_up_sync_key(wait_queue_head_t *q, unsigned int mode, int nr, void *key); -void __wake_up_locked(wait_queue_head_t *q, unsigned int mode, int nr); -void __wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr); -void __wake_up_bit(wait_queue_head_t *, void *, int); -int __wait_on_bit(wait_queue_head_t *, struct wait_bit_queue *, wait_bit_action_f *, unsigned); -int __wait_on_bit_lock(wait_queue_head_t *, struct wait_bit_queue *, wait_bit_action_f *, unsigned); +void __wake_up(struct wait_queue_head *wq_head, unsigned int mode, int nr, void *key); +void __wake_up_locked_key(struct wait_queue_head *wq_head, unsigned int mode, void *key); +void __wake_up_sync_key(struct wait_queue_head *wq_head, unsigned int mode, int nr, void *key); +void __wake_up_locked(struct wait_queue_head *wq_head, unsigned int mode, int nr); +void __wake_up_sync(struct wait_queue_head *wq_head, unsigned int mode, int nr); +void __wake_up_bit(struct wait_queue_head *, void *, int); +int __wait_on_bit(struct wait_queue_head *, struct wait_bit_queue *, wait_bit_action_f *, unsigned); +int __wait_on_bit_lock(struct wait_queue_head *, struct wait_bit_queue *, wait_bit_action_f *, unsigned); void wake_up_bit(void *, int); void wake_up_atomic_t(atomic_t *); int out_of_line_wait_on_bit(void *, int, wait_bit_action_f *, unsigned); int out_of_line_wait_on_bit_timeout(void *, int, wait_bit_action_f *, unsigned, unsigned long); int out_of_line_wait_on_bit_lock(void *, int, wait_bit_action_f *, unsigned); int out_of_line_wait_on_atomic_t(atomic_t *, int (*)(atomic_t *), unsigned); -wait_queue_head_t *bit_waitqueue(void *, int); +struct wait_queue_head *bit_waitqueue(void *, int); #define wake_up(x) __wake_up(x, TASK_NORMAL, 1, NULL) #define wake_up_nr(x, nr) __wake_up(x, TASK_NORMAL, nr, NULL) @@ -970,10 +970,10 @@ do { \ /* * Waitqueues which are removed from the waitqueue_head at wakeup time */ -void prepare_to_wait(wait_queue_head_t *q, struct wait_queue_entry *wq_entry, int state); -void prepare_to_wait_exclusive(wait_queue_head_t *q, struct wait_queue_entry *wq_entry, int state); -long prepare_to_wait_event(wait_queue_head_t *q, struct wait_queue_entry *wq_entry, int state); -void finish_wait(wait_queue_head_t *q, struct wait_queue_entry *wq_entry); +void prepare_to_wait(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry, int state); +void prepare_to_wait_exclusive(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry, int state); +long prepare_to_wait_event(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry, int state); +void finish_wait(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry); long wait_woken(struct wait_queue_entry *wq_entry, unsigned mode, long timeout); int woken_wake_function(struct wait_queue_entry *wq_entry, unsigned mode, int sync, void *key); int autoremove_wake_function(struct wait_queue_entry *wq_entry, unsigned mode, int sync, void *key); -- cgit v1.2.3 From 2141713616c652aeabf2dd5c1e89bc601c4fed6a Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Sun, 5 Mar 2017 11:25:39 +0100 Subject: sched/wait: Standardize 'struct wait_bit_queue' wait-queue entry field name Rename 'struct wait_bit_queue::wait' to ::wq_entry, to more clearly name it as a wait-queue entry. Propagate it to a couple of usage sites where the wait-bit-queue internals are exposed. Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar --- include/linux/wait.h | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'include/linux') diff --git a/include/linux/wait.h b/include/linux/wait.h index c3d1cefc7853..1c8add685f22 100644 --- a/include/linux/wait.h +++ b/include/linux/wait.h @@ -38,7 +38,7 @@ struct wait_bit_key { struct wait_bit_queue { struct wait_bit_key key; - struct wait_queue_entry wait; + struct wait_queue_entry wq_entry; }; struct wait_queue_head { @@ -991,11 +991,11 @@ int wake_bit_function(struct wait_queue_entry *wq_entry, unsigned mode, int sync #define DEFINE_WAIT_BIT(name, word, bit) \ struct wait_bit_queue name = { \ .key = __WAIT_BIT_KEY_INITIALIZER(word, bit), \ - .wait = { \ + .wq_entry = { \ .private = current, \ .func = wake_bit_function, \ .task_list = \ - LIST_HEAD_INIT((name).wait.task_list), \ + LIST_HEAD_INIT((name).wq_entry.task_list), \ }, \ } -- cgit v1.2.3 From 76c85ddc4695bb7b8209bfeff11f5156088f9197 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Sun, 5 Mar 2017 11:35:27 +0100 Subject: sched/wait: Standardize wait_bit_queue naming So wait-bit-queue head variables are often named: struct wait_bit_queue *q ... which is a bit ambiguous and super confusing, because they clearly suggest wait-queue head semantics and behavior (they rhyme with the old wait_queue_t *q naming), while they are extended wait-queue _entries_, not heads! They are misnomers in two ways: - the 'wait_bit_queue' leaves open the question of whether it's an entry or a head - the 'q' parameter and local variable naming falsely implies that it's a 'queue' - while it's an entry. This resulted in sometimes confusing cases such as: finish_wait(wq, &q->wait); where the 'q' is not a wait-queue head, but a wait-bit-queue entry. So improve this all by standardizing wait-bit-queue nomenclature similar to wait-queue head naming: struct wait_bit_queue => struct wait_bit_queue_entry q => wbq_entry Which makes it all a much clearer: struct wait_bit_queue_entry *wbq_entry ... and turns the former confusing piece of code into: finish_wait(wq_head, &wbq_entry->wq_entry; which IMHO makes it apparently clear what we are doing, without having to analyze the context of the code: we are adding a wait-queue entry to a regular wait-queue head, which entry is embedded in a wait-bit-queue entry. I'm not a big fan of acronyms, but repeating wait_bit_queue_entry in field and local variable names is too long, so Hopefully it's clear enough that 'wq_' prefixes stand for wait-queues, while 'wbq_' prefixes stand for wait-bit-queues. Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar --- include/linux/wait.h | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'include/linux') diff --git a/include/linux/wait.h b/include/linux/wait.h index 1c8add685f22..fc7c32d82120 100644 --- a/include/linux/wait.h +++ b/include/linux/wait.h @@ -36,7 +36,7 @@ struct wait_bit_key { unsigned long timeout; }; -struct wait_bit_queue { +struct wait_bit_queue_entry { struct wait_bit_key key; struct wait_queue_entry wq_entry; }; @@ -207,8 +207,8 @@ void __wake_up_sync_key(struct wait_queue_head *wq_head, unsigned int mode, int void __wake_up_locked(struct wait_queue_head *wq_head, unsigned int mode, int nr); void __wake_up_sync(struct wait_queue_head *wq_head, unsigned int mode, int nr); void __wake_up_bit(struct wait_queue_head *, void *, int); -int __wait_on_bit(struct wait_queue_head *, struct wait_bit_queue *, wait_bit_action_f *, unsigned); -int __wait_on_bit_lock(struct wait_queue_head *, struct wait_bit_queue *, wait_bit_action_f *, unsigned); +int __wait_on_bit(struct wait_queue_head *, struct wait_bit_queue_entry *, wait_bit_action_f *, unsigned); +int __wait_on_bit_lock(struct wait_queue_head *, struct wait_bit_queue_entry *, wait_bit_action_f *, unsigned); void wake_up_bit(void *, int); void wake_up_atomic_t(atomic_t *); int out_of_line_wait_on_bit(void *, int, wait_bit_action_f *, unsigned); @@ -989,7 +989,7 @@ int wake_bit_function(struct wait_queue_entry *wq_entry, unsigned mode, int sync #define DEFINE_WAIT(name) DEFINE_WAIT_FUNC(name, autoremove_wake_function) #define DEFINE_WAIT_BIT(name, word, bit) \ - struct wait_bit_queue name = { \ + struct wait_bit_queue_entry name = { \ .key = __WAIT_BIT_KEY_INITIALIZER(word, bit), \ .wq_entry = { \ .private = current, \ -- cgit v1.2.3 From 939798a072300698870b96756c38bb34c20f6c71 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Sun, 5 Mar 2017 11:54:46 +0100 Subject: sched/wait: Improve the bit-wait API parameter names in the API function prototypes Contrary to kernel tradition, most of the bit-wait function prototypes in don't fully define the parameter names, they only list the types: int out_of_line_wait_on_bit_timeout(void *, int, wait_bit_action_f *, unsigned, unsigned long); ... which is pretty passive-aggressive in terms of informing the reader about what these functions are doing. Fill in the parameter names, such as: int out_of_line_wait_on_bit_timeout(void *word, int, wait_bit_action_f *action, unsigned int mode, unsigned long timeout); Also turn spurious (and inconsistently utilized) cases of 'unsigned' into 'unsigned int'. Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar --- include/linux/wait.h | 30 +++++++++++++++--------------- 1 file changed, 15 insertions(+), 15 deletions(-) (limited to 'include/linux') diff --git a/include/linux/wait.h b/include/linux/wait.h index fc7c32d82120..1338505d8b9f 100644 --- a/include/linux/wait.h +++ b/include/linux/wait.h @@ -200,22 +200,22 @@ __remove_wait_queue(struct wait_queue_head *wq_head, struct wait_queue_entry *wq list_del(&wq_entry->task_list); } -typedef int wait_bit_action_f(struct wait_bit_key *, int mode); +typedef int wait_bit_action_f(struct wait_bit_key *key, int mode); void __wake_up(struct wait_queue_head *wq_head, unsigned int mode, int nr, void *key); void __wake_up_locked_key(struct wait_queue_head *wq_head, unsigned int mode, void *key); void __wake_up_sync_key(struct wait_queue_head *wq_head, unsigned int mode, int nr, void *key); void __wake_up_locked(struct wait_queue_head *wq_head, unsigned int mode, int nr); void __wake_up_sync(struct wait_queue_head *wq_head, unsigned int mode, int nr); -void __wake_up_bit(struct wait_queue_head *, void *, int); -int __wait_on_bit(struct wait_queue_head *, struct wait_bit_queue_entry *, wait_bit_action_f *, unsigned); -int __wait_on_bit_lock(struct wait_queue_head *, struct wait_bit_queue_entry *, wait_bit_action_f *, unsigned); -void wake_up_bit(void *, int); -void wake_up_atomic_t(atomic_t *); -int out_of_line_wait_on_bit(void *, int, wait_bit_action_f *, unsigned); -int out_of_line_wait_on_bit_timeout(void *, int, wait_bit_action_f *, unsigned, unsigned long); -int out_of_line_wait_on_bit_lock(void *, int, wait_bit_action_f *, unsigned); -int out_of_line_wait_on_atomic_t(atomic_t *, int (*)(atomic_t *), unsigned); -struct wait_queue_head *bit_waitqueue(void *, int); +void __wake_up_bit(struct wait_queue_head *wq_head, void *word, int bit); +int __wait_on_bit(struct wait_queue_head *wq_head, struct wait_bit_queue_entry *wbq_entry, wait_bit_action_f *action, unsigned int mode); +int __wait_on_bit_lock(struct wait_queue_head *wq_head, struct wait_bit_queue_entry *wbq_entry, wait_bit_action_f *action, unsigned int mode); +void wake_up_bit(void *word, int bit); +void wake_up_atomic_t(atomic_t *p); +int out_of_line_wait_on_bit(void *word, int, wait_bit_action_f *action, unsigned int mode); +int out_of_line_wait_on_bit_timeout(void *word, int, wait_bit_action_f *action, unsigned int mode, unsigned long timeout); +int out_of_line_wait_on_bit_lock(void *word, int, wait_bit_action_f *action, unsigned int mode); +int out_of_line_wait_on_atomic_t(atomic_t *p, int (*)(atomic_t *), unsigned int mode); +struct wait_queue_head *bit_waitqueue(void *word, int bit); #define wake_up(x) __wake_up(x, TASK_NORMAL, 1, NULL) #define wake_up_nr(x, nr) __wake_up(x, TASK_NORMAL, nr, NULL) @@ -1008,10 +1008,10 @@ int wake_bit_function(struct wait_queue_entry *wq_entry, unsigned mode, int sync } while (0) -extern int bit_wait(struct wait_bit_key *, int); -extern int bit_wait_io(struct wait_bit_key *, int); -extern int bit_wait_timeout(struct wait_bit_key *, int); -extern int bit_wait_io_timeout(struct wait_bit_key *, int); +extern int bit_wait(struct wait_bit_key