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Date: Sat, 10 Mar 2012 11:16:48 +0800 From: Lai Jiangshan <eag0628@...il.com> To: paulmck@...ux.vnet.ibm.com Cc: Lai Jiangshan <laijs@...fujitsu.com>, linux-kernel@...r.kernel.org, mingo@...e.hu, dipankar@...ibm.com, akpm@...ux-foundation.org, mathieu.desnoyers@...ymtl.ca, josh@...htriplett.org, niv@...ibm.com, tglx@...utronix.de, peterz@...radead.org, rostedt@...dmis.org, Valdis.Kletnieks@...edu, dhowells@...hat.com, eric.dumazet@...il.com, darren@...art.com, fweisbec@...il.com, patches@...aro.org Subject: Re: [RFC PATCH 5/5 single-thread-version] implement per-domain single-thread state machine call_srcu() On Fri, Mar 9, 2012 at 4:35 AM, Paul E. McKenney <paulmck@...ux.vnet.ibm.com> wrote: > On Wed, Mar 07, 2012 at 11:54:02AM +0800, Lai Jiangshan wrote: >> This patch is on the top of the 4 previous patches(1/6, 2/6, 3/6, 4/6). >> >> o state machine is light way and single-threaded, it is preemptible when checking. >> >> o state machine is a work_struct. So, there is no thread occupied >> by SRCU when the srcu is not actived(no callback). And it does >> not sleep(avoid to occupy a thread when sleep). >> >> o state machine is the only thread can flip/check/write(*) the srcu_struct, >> so we don't need any mutex. >> (write(*): except ->per_cpu_ref, ->running, ->batch_queue) >> >> o synchronize_srcu() is always call call_srcu(). >> synchronize_srcu_expedited() is also. >> It is OK for mb()-based srcu are extremely fast. >> >> o In current kernel, we can expect that there are only 1 callback per gp. >> so callback is probably called in the same CPU when it is queued. >> >> The trip of a callback: >> 1) ->batch_queue when call_srcu() >> >> 2) ->batch_check0 when try to do check_zero >> >> 3) ->batch_check1 after finish its first check_zero and the flip >> >> 4) ->batch_done after finish its second check_zero >> >> The current requirement of the callbacks: >> The callback will be called inside process context. >> The callback should be fast without any sleeping path. >> >> Signed-off-by: Lai Jiangshan <laijs@...fujitsu.com> >> --- >> include/linux/rcupdate.h | 2 +- >> include/linux/srcu.h | 28 +++++- >> kernel/rcupdate.c | 24 ++++- >> kernel/rcutorture.c | 44 ++++++++- >> kernel/srcu.c | 238 ++++++++++++++++++++++++++++++++------------- >> 5 files changed, 259 insertions(+), 77 deletions(-) >> diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h >> index 9372174..d98eab2 100644 >> --- a/include/linux/rcupdate.h >> +++ b/include/linux/rcupdate.h >> @@ -222,7 +222,7 @@ extern void rcu_irq_exit(void); >> * TREE_RCU and rcu_barrier_() primitives in TINY_RCU. >> */ >> >> -typedef void call_rcu_func_t(struct rcu_head *head, >> +typedef void (*call_rcu_func_t)(struct rcu_head *head, > > I don't see what this applies against. The old patch 5/6 created > a "(*call_rcu_func_t)(struct rcu_head *head," and I don't see what > created the "call_rcu_func_t(struct rcu_head *head,". typedef void call_rcu_func_t(...) declares a function type, not a function pointer type. I use a line of code as following: call_rcu_func_t crf = func; if call_rcu_func_t is a function type, the above code can't be complied, I need to covert it to function pointer type. > >> void (*func)(struct rcu_head *head)); >> void wait_rcu_gp(call_rcu_func_t crf); >> >> diff --git a/include/linux/srcu.h b/include/linux/srcu.h >> index df8f5f7..56cb774 100644 >> --- a/include/linux/srcu.h >> +++ b/include/linux/srcu.h >> @@ -29,6 +29,7 @@ >> >> #include <linux/mutex.h> >> #include <linux/rcupdate.h> >> +#include <linux/workqueue.h> >> >> struct srcu_struct_array { >> unsigned long c[2]; >> @@ -39,10 +40,23 @@ struct srcu_struct_array { >> #define SRCU_REF_MASK (ULONG_MAX >> SRCU_USAGE_BITS) >> #define SRCU_USAGE_COUNT (SRCU_REF_MASK + 1) >> >> +struct rcu_batch { >> + struct rcu_head *head, **tail; >> +}; >> + >> struct srcu_struct { >> unsigned completed; >> struct srcu_struct_array __percpu *per_cpu_ref; >> - struct mutex mutex; >> + spinlock_t queue_lock; /* protect ->batch_queue, ->running */ >> + bool running; >> + /* callbacks just queued */ >> + struct rcu_batch batch_queue; >> + /* callbacks try to do the first check_zero */ >> + struct rcu_batch batch_check0; >> + /* callbacks done with the first check_zero and the flip */ >> + struct rcu_batch batch_check1; >> + struct rcu_batch batch_done; >> + struct delayed_work work; > > Why not use your multiple-tail-pointer trick here? (The one that is > used in treercu.) 1) Make the code of the advance of batches simpler. 2) batch_queue is protected by lock, so it will be hard to use multiple-tail-pointer trick. 3) rcu_batch API do add a little more runtime overhead, but this overhead is just several cpu-instructions, I think it is OK. It is good tradeoff when compare to the readability. I think we can also use rcu_batch for rcutree/rcutiny. > >> unsigned long snap[NR_CPUS]; >> #ifdef CONFIG_DEBUG_LOCK_ALLOC >> struct lockdep_map dep_map; >> @@ -67,12 +81,24 @@ int init_srcu_struct(struct srcu_struct *sp); >> >> #endif /* #else #ifdef CONFIG_DEBUG_LOCK_ALLOC */ >> >> +/* draft >> + * queue callbacks which will be invoked after grace period. >> + * The callback will be called inside process context. >> + * The callback should be fast without any sleeping path. >> + */ >> +void call_srcu(struct srcu_struct *sp, struct rcu_head *head, >> + void (*func)(struct rcu_head *head)); >> + >> +typedef void (*call_srcu_func_t)(struct srcu_struct *sp, struct rcu_head *head, >> + void (*func)(struct rcu_head *head)); >> +void __wait_srcu_gp(struct srcu_struct *sp, call_srcu_func_t crf); >> void cleanup_srcu_struct(struct srcu_struct *sp); >> int __srcu_read_lock(struct srcu_struct *sp) __acquires(sp); >> void __srcu_read_unlock(struct srcu_struct *sp, int idx) __releases(sp); >> void synchronize_srcu(struct srcu_struct *sp); >> void synchronize_srcu_expedited(struct srcu_struct *sp); >> long srcu_batches_completed(struct srcu_struct *sp); >> +void srcu_barrier(struct srcu_struct *sp); >> >> #ifdef CONFIG_DEBUG_LOCK_ALLOC >> >> diff --git a/kernel/rcupdate.c b/kernel/rcupdate.c >> index a86f174..f9b551f 100644 >> --- a/kernel/rcupdate.c >> +++ b/kernel/rcupdate.c >> @@ -45,6 +45,7 @@ >> #include <linux/mutex.h> >> #include <linux/export.h> >> #include <linux/hardirq.h> >> +#include <linux/srcu.h> >> >> #define CREATE_TRACE_POINTS >> #include <trace/events/rcu.h> >> @@ -123,20 +124,39 @@ static void wakeme_after_rcu(struct rcu_head *head) >> complete(&rcu->completion); >> } >> >> -void wait_rcu_gp(call_rcu_func_t crf) >> +static void __wait_rcu_gp(void *domain, void *func) >> { >> struct rcu_synchronize rcu; >> >> init_rcu_head_on_stack(&rcu.head); >> init_completion(&rcu.completion); >> + >> /* Will wake me after RCU finished. */ >> - crf(&rcu.head, wakeme_after_rcu); >> + if (!domain) { >> + call_rcu_func_t crf = func; >> + crf(&rcu.head, wakeme_after_rcu); >> + } else { >> + call_srcu_func_t crf = func; >> + crf(domain, &rcu.head, wakeme_after_rcu); >> + } >> + >> /* Wait for it. */ >> wait_for_completion(&rcu.completion); >> destroy_rcu_head_on_stack(&rcu.head); >> } > > Mightn't it be simpler and faster to just have a separate wait_srcu_gp() > that doesn't share code with wait_rcu_gp()? I am all for sharing code, > but this might be hrting more than helping. > >> + >> +void wait_rcu_gp(call_rcu_func_t crf) >> +{ >> + __wait_rcu_gp(NULL, crf); >> +} >> EXPORT_SYMBOL_GPL(wait_rcu_gp); >> >> +/* srcu.c internel */ >> +void __wait_srcu_gp(struct srcu_struct *sp, call_srcu_func_t crf) >> +{ >> + __wait_rcu_gp(sp, crf); >> +} >> + >> #ifdef CONFIG_PROVE_RCU >> /* >> * wrapper function to avoid #include problems. >> diff --git a/kernel/rcutorture.c b/kernel/rcutorture.c >> index 54e5724..40d24d0 100644 > > OK, so your original patch #6 is folded into this? I don't have a strong > view either way, just need to know. > >> --- a/kernel/rcutorture.c >> +++ b/kernel/rcutorture.c >> @@ -623,6 +623,11 @@ static int srcu_torture_completed(void) >> return srcu_batches_completed(&srcu_ctl); >> } >> >> +static void srcu_torture_deferred_free(struct rcu_torture *rp) >> +{ >> + call_srcu(&srcu_ctl, &rp->rtort_rcu, rcu_torture_cb); >> +} >> + >> static void srcu_torture_synchronize(void) >> { >> synchronize_srcu(&srcu_ctl); >> @@ -652,7 +657,7 @@ static struct rcu_torture_ops srcu_ops = { >> .read_delay = srcu_read_delay, >> .readunlock = srcu_torture_read_unlock, >> .completed = srcu_torture_completed, >> - .deferred_free = rcu_sync_torture_deferred_free, >> + .deferred_free = srcu_torture_deferred_free, >> .sync = srcu_torture_synchronize, >> .call = NULL, >> .cb_barrier = NULL, >> @@ -660,6 +665,21 @@ static struct rcu_torture_ops srcu_ops = { >> .name = "srcu" >> }; >> >> +static struct rcu_torture_ops srcu_sync_ops = { >> + .init = srcu_torture_init, >> + .cleanup = srcu_torture_cleanup, >> + .readlock = srcu_torture_read_lock, >> + .read_delay = srcu_read_delay, >> + .readunlock = srcu_torture_read_unlock, >> + .completed = srcu_torture_completed, >> + .deferred_free = rcu_sync_torture_deferred_free, >> + .sync = srcu_torture_synchronize, >> + .call = NULL, >> + .cb_barrier = NULL, >> + .stats = srcu_torture_stats, >> + .name = "srcu_sync" >> +}; >> + >> static int srcu_torture_read_lock_raw(void) __acquires(&srcu_ctl) >> { >> return srcu_read_lock_raw(&srcu_ctl); >> @@ -677,7 +697,7 @@ static struct rcu_torture_ops srcu_raw_ops = { >> .read_delay = srcu_read_delay, >> .readunlock = srcu_torture_read_unlock_raw, >> .completed = srcu_torture_completed, >> - .deferred_free = rcu_sync_torture_deferred_free, >> + .deferred_free = srcu_torture_deferred_free, >> .sync = srcu_torture_synchronize, >> .call = NULL, >> .cb_barrier = NULL, >> @@ -685,6 +705,21 @@ static struct rcu_torture_ops srcu_raw_ops = { >> .name = "srcu_raw" >> }; >> >> +static struct rcu_torture_ops srcu_raw_sync_ops = { >> + .init = srcu_torture_init, >> + .cleanup = srcu_torture_cleanup, >> + .readlock = srcu_torture_read_lock_raw, >> + .read_delay = srcu_read_delay, >> + .readunlock = srcu_torture_read_unlock_raw, >> + .completed = srcu_torture_completed, >> + .deferred_free = rcu_sync_torture_deferred_free, >> + .sync = srcu_torture_synchronize, >> + .call = NULL, >> + .cb_barrier = NULL, >> + .stats = srcu_torture_stats, >> + .name = "srcu_raw_sync" >> +}; >> + >> static void srcu_torture_synchronize_expedited(void) >> { >> synchronize_srcu_expedited(&srcu_ctl); >> @@ -1673,7 +1708,7 @@ static int rcu_torture_barrier_init(void) >> for (i = 0; i < n_barrier_cbs; i++) { >> init_waitqueue_head(&barrier_cbs_wq[i]); >> barrier_cbs_tasks[i] = kthread_run(rcu_torture_barrier_cbs, >> - (void *)i, >> + (void *)(long)i, >> "rcu_torture_barrier_cbs"); >> if (IS_ERR(barrier_cbs_tasks[i])) { >> ret = PTR_ERR(barrier_cbs_tasks[i]); >> @@ -1857,7 +1892,8 @@ rcu_torture_init(void) >> static struct rcu_torture_ops *torture_ops[] = >> { &rcu_ops, &rcu_sync_ops, &rcu_expedited_ops, >> &rcu_bh_ops, &rcu_bh_sync_ops, &rcu_bh_expedited_ops, >> - &srcu_ops, &srcu_raw_ops, &srcu_expedited_ops, >> + &srcu_ops, &srcu_sync_ops, &srcu_raw_ops, >> + &srcu_raw_sync_ops, &srcu_expedited_ops, >> &sched_ops, &sched_sync_ops, &sched_expedited_ops, }; >> >> mutex_lock(&fullstop_mutex); >> diff --git a/kernel/srcu.c b/kernel/srcu.c >> index d101ed5..532f890 100644 >> --- a/kernel/srcu.c >> +++ b/kernel/srcu.c >> @@ -34,10 +34,60 @@ >> #include <linux/delay.h> >> #include <linux/srcu.h> >> >> +static inline void rcu_batch_init(struct rcu_batch *b) >> +{ >> + b->head = NULL; >> + b->tail = &b->head; >> +} >> + >> +static inline void rcu_batch_queue(struct rcu_batch *b, struct rcu_head *head) >> +{ >> + *b->tail = head; >> + b->tail = &head->next; >> +} >> + >> +static inline bool rcu_batch_empty(struct rcu_batch *b) >> +{ >> + return b->tail == &b->head; >> +} >> + >> +static inline struct rcu_head *rcu_batch_dequeue(struct rcu_batch *b) >> +{ >> + struct rcu_head *head; >> + >> + if (rcu_batch_empty(b)) >> + return NULL; >> + >> + head = b->head; >> + b->head = head->next; >> + if (b->tail == &head->next) >> + rcu_batch_init(b); >> + >> + return head; >> +} >> + >> +static inline void rcu_batch_move(struct rcu_batch *to, struct rcu_batch *from) >> +{ >> + if (!rcu_batch_empty(from)) { >> + *to->tail = from->head; >> + to->tail = from->tail; >> + rcu_batch_init(from); >> + } >> +} > > And perhaps this is why you don't want the multi-tailed queue? > >> + >> +/* single-thread state-machine */ >> +static void process_srcu(struct work_struct *work); >> + >> static int init_srcu_struct_fields(struct srcu_struct *sp) >> { >> sp->completed = 0; >> - mutex_init(&sp->mutex); >> + spin_lock_init(&sp->queue_lock); >> + sp->running = false; >> + rcu_batch_init(&sp->batch_queue); >> + rcu_batch_init(&sp->batch_check0); >> + rcu_batch_init(&sp->batch_check1); >> + rcu_batch_init(&sp->batch_done); >> + INIT_DELAYED_WORK(&sp->work, process_srcu); >> sp->per_cpu_ref = alloc_percpu(struct srcu_struct_array); >> return sp->per_cpu_ref ? 0 : -ENOMEM; >> } >> @@ -254,11 +304,9 @@ EXPORT_SYMBOL_GPL(__srcu_read_unlock); >> * we repeatedly block for 1-millisecond time periods. This approach >> * has done well in testing, so there is no need for a config parameter. >> */ >> -#define SYNCHRONIZE_SRCU_READER_DELAY 5 >> -#define SYNCHRONIZE_SRCU_TRYCOUNT 2 >> -#define SYNCHRONIZE_SRCU_EXP_TRYCOUNT 12 >> +#define SRCU_RETRY_CHECK_DELAY 5 >> >> -static void wait_idx(struct srcu_struct *sp, int idx, int trycount) >> +static bool try_check_zero(struct srcu_struct *sp, int idx, int trycount) >> { >> /* >> * If a reader fetches the index before the ->completed increment, >> @@ -271,19 +319,12 @@ static void wait_idx(struct srcu_struct *sp, int idx, int trycount) >> */ >> smp_mb(); /* D */ >> >> - /* >> - * SRCU read-side critical sections are normally short, so wait >> - * a small amount of time before possibly blocking. >> - */ >> - if (!srcu_readers_active_idx_check(sp, idx)) { >> - udelay(SYNCHRONIZE_SRCU_READER_DELAY); >> - while (!srcu_readers_active_idx_check(sp, idx)) { >> - if (trycount > 0) { >> - trycount--; >> - udelay(SYNCHRONIZE_SRCU_READER_DELAY); >> - } else >> - schedule_timeout_interruptible(1); >> - } >> + for (;;) { >> + if (srcu_readers_active_idx_check(sp, idx)) >> + break; >> + if (--trycount <= 0) >> + return false; >> + udelay(SRCU_RETRY_CHECK_DELAY); >> } >> >> /* >> @@ -297,6 +338,8 @@ static void wait_idx(struct srcu_struct *sp, int idx, int trycount) >> * the next flipping. >> */ >> smp_mb(); /* E */ >> + >> + return true; >> } >> >> /* >> @@ -308,10 +351,27 @@ static void srcu_flip(struct srcu_struct *sp) >> ACCESS_ONCE(sp->completed)++; >> } >> >> +void call_srcu(struct srcu_struct *sp, struct rcu_head *head, >> + void (*func)(struct rcu_head *head)) >> +{ >> + unsigned long flags; >> + >> + head->next = NULL; >> + head->func = func; >> + spin_lock_irqsave(&sp->queue_lock, flags); >> + rcu_batch_queue(&sp->batch_queue, head); >> + if (!sp->running) { >> + sp->running = true; >> + queue_delayed_work(system_nrt_wq, &sp->work, 0); >> + } >> + spin_unlock_irqrestore(&sp->queue_lock, flags); >> +} >> +EXPORT_SYMBOL_GPL(call_srcu); >> + >> /* >> * Helper function for synchronize_srcu() and synchronize_srcu_expedited(). >> */ >> -static void __synchronize_srcu(struct srcu_struct *sp, int trycount) >> +static void __synchronize_srcu(struct srcu_struct *sp) >> { >> rcu_lockdep_assert(!lock_is_held(&sp->dep_map) && >> !lock_is_held(&rcu_bh_lock_map) && >> @@ -319,54 +379,7 @@ static void __synchronize_srcu(struct srcu_struct *sp, int trycount) >> !lock_is_held(&rcu_sched_lock_map), >> "Illegal synchronize_srcu() in same-type SRCU (or RCU) read-side critical section"); >> >> - mutex_lock(&sp->mutex); >> - >> - /* >> - * Suppose that during the previous grace period, a reader >> - * picked up the old value of the index, but did not increment >> - * its counter until after the previous instance of >> - * __synchronize_srcu() did the counter summation and recheck. >> - * That previous grace period was OK because the reader did >> - * not start until after the grace period started, so the grace >> - * period was not obligated to wait for that reader. >> - * >> - * However, the current SRCU grace period does have to wait for >> - * that reader. This is handled by invoking wait_idx() on the >> - * non-active set of counters (hence sp->completed - 1). Once >> - * wait_idx() returns, we know that all readers that picked up >> - * the old value of ->completed and that already incremented their >> - * counter will have completed. >> - * >> - * But what about readers that picked up the old value of >> - * ->completed, but -still- have not managed to increment their >> - * counter? We do not need to wait for those readers, because >> - * they will have started their SRCU read-side critical section >> - * after the current grace period starts. >> - * >> - * Because it is unlikely that readers will be preempted between >> - * fetching ->completed and incrementing their counter, wait_idx() >> - * will normally not need to wait. >> - */ >> - wait_idx(sp, (sp->completed - 1) & 0x1, trycount); >> - >> - /* >> - * Now that wait_idx() has waited for the really old readers, >> - * >> - * Flip the readers' index by incrementing ->completed, then wait >> - * until there are no more readers using the counters referenced by >> - * the old index value. (Recall that the index is the bottom bit >> - * of ->completed.) >> - * >> - * Of course, it is possible that a reader might be delayed for the >> - * full duration of flip_idx_and_wait() between fetching the >> - * index and incrementing its counter. This possibility is handled >> - * by the next __synchronize_srcu() invoking wait_idx() for such >> - * readers before starting a new grace period. >> - */ >> - srcu_flip(sp); >> - wait_idx(sp, (sp->completed - 1) & 0x1, trycount); >> - >> - mutex_unlock(&sp->mutex); >> + __wait_srcu_gp(sp, call_srcu); >> } >> >> /** >> @@ -385,7 +398,7 @@ static void __synchronize_srcu(struct srcu_struct *sp, int trycount) >> */ >> void synchronize_srcu(struct srcu_struct *sp) >> { >> - __synchronize_srcu(sp, SYNCHRONIZE_SRCU_TRYCOUNT); >> + __synchronize_srcu(sp); >> } >> EXPORT_SYMBOL_GPL(synchronize_srcu); >> >> @@ -406,10 +419,16 @@ EXPORT_SYMBOL_GPL(synchronize_srcu); >> */ >> void synchronize_srcu_expedited(struct srcu_struct *sp) >> { >> - __synchronize_srcu(sp, SYNCHRONIZE_SRCU_EXP_TRYCOUNT); >> + __synchronize_srcu(sp); >> } > > OK, I'll bite... Why aren't synchronize_srcu_expedited() and > synchronize_srcu() different? In mb()-based srcu, synchronize_srcu() is very fast, synchronize_srcu_expedited() makes less sense than before. But when wait_srcu_gp() is move back here, I will use a bigger "trycount" for synchronize_srcu_expedited(). And any problem for srcu_advance_batches()? Thanks. Lai > > Thanx, Paul > >> EXPORT_SYMBOL_GPL(synchronize_srcu_expedited); >> >> +void srcu_barrier(struct srcu_struct *sp) >> +{ >> + __synchronize_srcu(sp); >> +} >> +EXPORT_SYMBOL_GPL(srcu_barrier); >> + >> /** >> * srcu_batches_completed - return batches completed. >> * @sp: srcu_struct on which to report batch completion. >> @@ -423,3 +442,84 @@ long srcu_batches_completed(struct srcu_struct *sp) >> return sp->completed; >> } >> EXPORT_SYMBOL_GPL(srcu_batches_completed); >> + >> +#define SRCU_CALLBACK_BATCH 10 >> +#define SRCU_INTERVAL 1 >> + >> +static void srcu_collect_new(struct srcu_struct *sp) >> +{ >> + if (!rcu_batch_empty(&sp->batch_queue)) { >> + spin_lock_irq(&sp->queue_lock); >> + rcu_batch_move(&sp->batch_check0, &sp->batch_queue); >> + spin_unlock_irq(&sp->queue_lock); >> + } >> +} >> + >> +static void srcu_advance_batches(struct srcu_struct *sp) >> +{ >> + int idx = 1 - (sp->completed & 0x1UL); >> + >> + /* >> + * SRCU read-side critical sections are normally short, so check >> + * twice after a flip. >> + */ >> + if (!rcu_batch_empty(&sp->batch_check1) || >> + !rcu_batch_empty(&sp->batch_check0)) { >> + if (try_check_zero(sp, idx, 1)) { >> + rcu_batch_move(&sp->batch_done, &sp->batch_check1); >> + rcu_batch_move(&sp->batch_check1, &sp->batch_check0); >> + if (!rcu_batch_empty(&sp->batch_check1)) { >> + srcu_flip(sp); >> + if (try_check_zero(sp, 1 - idx, 2)) { >> + rcu_batch_move(&sp->batch_done, >> + &sp->batch_check1); >> + } >> + } >> + } >> + } >> +} >> + >> +static void srcu_invoke_callbacks(struct srcu_struct *sp) >> +{ >> + int i; >> + struct rcu_head *head; >> + >> + for (i = 0; i < SRCU_CALLBACK_BATCH; i++) { >> + head = rcu_batch_dequeue(&sp->batch_done); >> + if (!head) >> + break; >> + head->func(head); >> + } >> +} >> + >> +static void srcu_reschedule(struct srcu_struct *sp) >> +{ >> + bool running = true; >> + >> + if (rcu_batch_empty(&sp->batch_done) && >> + rcu_batch_empty(&sp->batch_check1) && >> + rcu_batch_empty(&sp->batch_check0) && >> + rcu_batch_empty(&sp->batch_queue)) { >> + spin_lock_irq(&sp->queue_lock); >> + if (rcu_batch_empty(&sp->batch_queue)) { >> + sp->running = false; >> + running = false; >> + } >> + spin_unlock_irq(&sp->queue_lock); >> + } >> + >> + if (running) >> + queue_delayed_work(system_nrt_wq, &sp->work, SRCU_INTERVAL); >> +} >> + >> +static void process_srcu(struct work_struct *work) >> +{ >> + struct srcu_struct *sp; >> + >> + sp = container_of(work, struct srcu_struct, work.work); >> + >> + srcu_collect_new(sp); >> + srcu_advance_batches(sp); >> + srcu_invoke_callbacks(sp); >> + srcu_reschedule(sp); >> +} >> >> >> > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@...r.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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