Date: Tue, 12 Jan 2010 07:02:55 +0000 (UTC) From: Kip Macy <kmacy@FreeBSD.org> To: src-committers@freebsd.org, svn-src-user@freebsd.org Subject: svn commit: r202139 - user/kmacy/releng_8_rump/lib/libunet Message-ID: <201001120702.o0C72tc4009289@svn.freebsd.org>
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Author: kmacy Date: Tue Jan 12 07:02:54 2010 New Revision: 202139 URL: http://svn.freebsd.org/changeset/base/202139 Log: implement callout support using pthread condvars Modified: user/kmacy/releng_8_rump/lib/libunet/unet_glue.c user/kmacy/releng_8_rump/lib/libunet/unet_kern_intr.c user/kmacy/releng_8_rump/lib/libunet/unet_kern_timeout.c Modified: user/kmacy/releng_8_rump/lib/libunet/unet_glue.c ============================================================================== --- user/kmacy/releng_8_rump/lib/libunet/unet_glue.c Tue Jan 12 06:14:24 2010 (r202138) +++ user/kmacy/releng_8_rump/lib/libunet/unet_glue.c Tue Jan 12 07:02:54 2010 (r202139) @@ -35,6 +35,9 @@ SYSCTL_NODE(, CTL_NET, net, CTLFLAG SYSCTL_NODE(, CTL_VM, vm, CTLFLAG_RW, 0, "Virtual memory"); +SYSCTL_NODE(, CTL_DEBUG, debug, CTLFLAG_RW, 0, + "Debugging"); + MALLOC_DEFINE(M_DEVBUF, "devbuf", "device driver memory"); MALLOC_DEFINE(M_TEMP, "temp", "misc temporary data buffers"); Modified: user/kmacy/releng_8_rump/lib/libunet/unet_kern_intr.c ============================================================================== --- user/kmacy/releng_8_rump/lib/libunet/unet_kern_intr.c Tue Jan 12 06:14:24 2010 (r202138) +++ user/kmacy/releng_8_rump/lib/libunet/unet_kern_intr.c Tue Jan 12 07:02:54 2010 (r202139) @@ -27,6 +27,10 @@ __FBSDID("$FreeBSD$"); #include <sys/syslog.h> #include <sys/unistd.h> + +struct intr_event *clk_intr_event; + + /* * Bind an interrupt event to the specified CPU. Note that not all * platforms support binding an interrupt to a CPU. For those Modified: user/kmacy/releng_8_rump/lib/libunet/unet_kern_timeout.c ============================================================================== --- user/kmacy/releng_8_rump/lib/libunet/unet_kern_timeout.c Tue Jan 12 06:14:24 2010 (r202138) +++ user/kmacy/releng_8_rump/lib/libunet/unet_kern_timeout.c Tue Jan 12 07:02:54 2010 (r202139) @@ -52,15 +52,42 @@ __FBSDID("$FreeBSD$"); #include <sys/mutex.h> #include <sys/proc.h> #include <sys/sdt.h> -#include <sys/sleepqueue.h> #include <sys/sysctl.h> #include <sys/smp.h> +#include <pthread.h> + +SDT_PROVIDER_DEFINE(callout_execute); +SDT_PROBE_DEFINE(callout_execute, kernel, , callout_start); +SDT_PROBE_ARGTYPE(callout_execute, kernel, , callout_start, 0, + "struct callout *"); +SDT_PROBE_DEFINE(callout_execute, kernel, , callout_end); +SDT_PROBE_ARGTYPE(callout_execute, kernel, , callout_end, 0, + "struct callout *"); + +static int avg_depth; +SYSCTL_INT(_debug, OID_AUTO, to_avg_depth, CTLFLAG_RD, &avg_depth, 0, + "Average number of items examined per softclock call. Units = 1/1000"); +static int avg_gcalls; +SYSCTL_INT(_debug, OID_AUTO, to_avg_gcalls, CTLFLAG_RD, &avg_gcalls, 0, + "Average number of Giant callouts made per softclock call. Units = 1/1000"); +static int avg_lockcalls; +SYSCTL_INT(_debug, OID_AUTO, to_avg_lockcalls, CTLFLAG_RD, &avg_lockcalls, 0, + "Average number of lock callouts made per softclock call. Units = 1/1000"); +static int avg_mpcalls; +SYSCTL_INT(_debug, OID_AUTO, to_avg_mpcalls, CTLFLAG_RD, &avg_mpcalls, 0, + "Average number of MP callouts made per softclock call. Units = 1/1000"); +/* + * TODO: + * allocate more timeout table slots when table overflows. + */ int callwheelsize, callwheelbits, callwheelmask; +pthread_cond_t callout_cv; + struct callout_cpu { - struct mtx cc_lock; + pthread_mutex_t cc_lock; struct callout *cc_callout; struct callout_tailq *cc_callwheel; struct callout_list cc_callfree; @@ -81,13 +108,377 @@ struct callout_cpu cc_cpu; #define CC_CPU(cpu) &cc_cpu #define CC_SELF() &cc_cpu #endif -#define CC_LOCK(cc) mtx_lock(&(cc)->cc_lock) -#define CC_UNLOCK(cc) mtx_unlock(&(cc)->cc_lock) +#define CC_LOCK(cc) pthread_mutex_lock(&(cc)->cc_lock) +#define CC_UNLOCK(cc) pthread_mutex_unlock(&(cc)->cc_lock) static int timeout_cpu; MALLOC_DEFINE(M_CALLOUT, "callout", "Callout datastructures"); +/** + * Locked by cc_lock: + * cc_curr - If a callout is in progress, it is curr_callout. + * If curr_callout is non-NULL, threads waiting in + * callout_drain() will be woken up as soon as the + * relevant callout completes. + * cc_cancel - Changing to 1 with both callout_lock and c_lock held + * guarantees that the current callout will not run. + * The softclock() function sets this to 0 before it + * drops callout_lock to acquire c_lock, and it calls + * the handler only if curr_cancelled is still 0 after + * c_lock is successfully acquired. + * cc_waiting - If a thread is waiting in callout_drain(), then + * callout_wait is nonzero. Set only when + * curr_callout is non-NULL. + */ + +/* + * kern_timeout_callwheel_alloc() - kernel low level callwheel initialization + * + * This code is called very early in the kernel initialization sequence, + * and may be called more then once. + */ +caddr_t +kern_timeout_callwheel_alloc(caddr_t v) +{ + struct callout_cpu *cc; + + timeout_cpu = PCPU_GET(cpuid); + cc = CC_CPU(timeout_cpu); + /* + * Calculate callout wheel size + */ + for (callwheelsize = 1, callwheelbits = 0; + callwheelsize < ncallout; + callwheelsize <<= 1, ++callwheelbits) + ; + callwheelmask = callwheelsize - 1; + + cc->cc_callout = (struct callout *)v; + v = (caddr_t)(cc->cc_callout + ncallout); + cc->cc_callwheel = (struct callout_tailq *)v; + v = (caddr_t)(cc->cc_callwheel + callwheelsize); + return(v); +} + +static void +callout_cpu_init(struct callout_cpu *cc) +{ + struct callout *c; + int i; + + pthread_mutex_init(&cc->cc_lock, NULL); + SLIST_INIT(&cc->cc_callfree); + for (i = 0; i < callwheelsize; i++) { + TAILQ_INIT(&cc->cc_callwheel[i]); + } + if (cc->cc_callout == NULL) + return; + for (i = 0; i < ncallout; i++) { + c = &cc->cc_callout[i]; + callout_init(c, 0); + c->c_flags = CALLOUT_LOCAL_ALLOC; + SLIST_INSERT_HEAD(&cc->cc_callfree, c, c_links.sle); + } +} + +/* + * kern_timeout_callwheel_init() - initialize previously reserved callwheel + * space. + * + * This code is called just once, after the space reserved for the + * callout wheel has been finalized. + */ +void +kern_timeout_callwheel_init(void) +{ + callout_cpu_init(CC_CPU(timeout_cpu)); +} + +/* + * Start standard softclock thread. + */ +void *softclock_ih; + +static void +start_softclock(void *dummy) +{ + struct callout_cpu *cc; +#ifdef SMP + int cpu; +#endif + cc = CC_CPU(timeout_cpu); + if (swi_add(&clk_intr_event, "clock", softclock, cc, SWI_CLOCK, + INTR_MPSAFE, &softclock_ih)) + panic("died while creating standard software ithreads"); + cc->cc_cookie = softclock_ih; +#ifdef SMP + for (cpu = 0; cpu <= mp_maxid; cpu++) { + if (cpu == timeout_cpu) + continue; + if (CPU_ABSENT(cpu)) + continue; + cc = CC_CPU(cpu); + if (swi_add(NULL, "clock", softclock, cc, SWI_CLOCK, + INTR_MPSAFE, &cc->cc_cookie)) + panic("died while creating standard software ithreads"); + cc->cc_callout = NULL; /* Only cpu0 handles timeout(). */ + cc->cc_callwheel = malloc( + sizeof(struct callout_tailq) * callwheelsize, M_CALLOUT, + M_WAITOK); + callout_cpu_init(cc); + } +#endif +} + +SYSINIT(start_softclock, SI_SUB_SOFTINTR, SI_ORDER_FIRST, start_softclock, NULL); + +void +callout_tick(void) +{ + struct callout_cpu *cc; + int need_softclock; + int bucket; + + /* + * Process callouts at a very low cpu priority, so we don't keep the + * relatively high clock interrupt priority any longer than necessary. + */ + need_softclock = 0; + cc = CC_SELF(); + pthread_mutex_lock(&cc->cc_lock); + for (; (cc->cc_softticks - ticks) < 0; cc->cc_softticks++) { + bucket = cc->cc_softticks & callwheelmask; + if (!TAILQ_EMPTY(&cc->cc_callwheel[bucket])) { + need_softclock = 1; + break; + } + } + pthread_mutex_unlock(&cc->cc_lock); + /* + * swi_sched acquires the thread lock, so we don't want to call it + * with cc_lock held; incorrect locking order. + */ + if (need_softclock) + swi_sched(cc->cc_cookie, 0); +} + +static struct callout_cpu * +callout_lock(struct callout *c) +{ + struct callout_cpu *cc; + int cpu; + + for (;;) { + cpu = c->c_cpu; + cc = CC_CPU(cpu); + CC_LOCK(cc); + if (cpu == c->c_cpu) + break; + CC_UNLOCK(cc); + } + return (cc); +} + +/* + * The callout mechanism is based on the work of Adam M. Costello and + * George Varghese, published in a technical report entitled "Redesigning + * the BSD Callout and Timer Facilities" and modified slightly for inclusion + * in FreeBSD by Justin T. Gibbs. The original work on the data structures + * used in this implementation was published by G. Varghese and T. Lauck in + * the paper "Hashed and Hierarchical Timing Wheels: Data Structures for + * the Efficient Implementation of a Timer Facility" in the Proceedings of + * the 11th ACM Annual Symposium on Operating Systems Principles, + * Austin, Texas Nov 1987. + */ + +/* + * Software (low priority) clock interrupt. + * Run periodic events from timeout queue. + */ +void +softclock(void *arg) +{ + struct callout_cpu *cc; + struct callout *c; + struct callout_tailq *bucket; + int curticks; + int steps; /* #steps since we last allowed interrupts */ + int depth; + int mpcalls; + int lockcalls; + int gcalls; +#ifdef DIAGNOSTIC + struct bintime bt1, bt2; + struct timespec ts2; + static uint64_t maxdt = 36893488147419102LL; /* 2 msec */ + static timeout_t *lastfunc; +#endif + +#ifndef MAX_SOFTCLOCK_STEPS +#define MAX_SOFTCLOCK_STEPS 100 /* Maximum allowed value of steps. */ +#endif /* MAX_SOFTCLOCK_STEPS */ + + mpcalls = 0; + lockcalls = 0; + gcalls = 0; + depth = 0; + steps = 0; + cc = (struct callout_cpu *)arg; + CC_LOCK(cc); + while (cc->cc_softticks != ticks) { + /* + * cc_softticks may be modified by hard clock, so cache + * it while we work on a given bucket. + */ + curticks = cc->cc_softticks; + cc->cc_softticks++; + bucket = &cc->cc_callwheel[curticks & callwheelmask]; + c = TAILQ_FIRST(bucket); + while (c) { + depth++; + if (c->c_time != curticks) { + c = TAILQ_NEXT(c, c_links.tqe); + ++steps; + if (steps >= MAX_SOFTCLOCK_STEPS) { + cc->cc_next = c; + /* Give interrupts a chance. */ + CC_UNLOCK(cc); + ; /* nothing */ + CC_LOCK(cc); + c = cc->cc_next; + steps = 0; + } + } else { + void (*c_func)(void *); + void *c_arg; + struct lock_class *class; + struct lock_object *c_lock; + int c_flags, sharedlock; + + cc->cc_next = TAILQ_NEXT(c, c_links.tqe); + TAILQ_REMOVE(bucket, c, c_links.tqe); + class = (c->c_lock != NULL) ? + LOCK_CLASS(c->c_lock) : NULL; + sharedlock = (c->c_flags & CALLOUT_SHAREDLOCK) ? + 0 : 1; + c_lock = c->c_lock; + c_func = c->c_func; + c_arg = c->c_arg; + c_flags = c->c_flags; + if (c->c_flags & CALLOUT_LOCAL_ALLOC) { + c->c_flags = CALLOUT_LOCAL_ALLOC; + } else { + c->c_flags = + (c->c_flags & ~CALLOUT_PENDING); + } + cc->cc_curr = c; + cc->cc_cancel = 0; + CC_UNLOCK(cc); + if (c_lock != NULL) { + class->lc_lock(c_lock, sharedlock); + /* + * The callout may have been cancelled + * while we switched locks. + */ + if (cc->cc_cancel) { + class->lc_unlock(c_lock); + goto skip; + } + /* The callout cannot be stopped now. */ + cc->cc_cancel = 1; + + if (c_lock == &Giant.lock_object) { + gcalls++; + CTR3(KTR_CALLOUT, + "callout %p func %p arg %p", + c, c_func, c_arg); + } else { + lockcalls++; + CTR3(KTR_CALLOUT, "callout lock" + " %p func %p arg %p", + c, c_func, c_arg); + } + } else { + mpcalls++; + CTR3(KTR_CALLOUT, + "callout mpsafe %p func %p arg %p", + c, c_func, c_arg); + } +#ifdef DIAGNOSTIC + binuptime(&bt1); +#endif + THREAD_NO_SLEEPING(); + SDT_PROBE(callout_execute, kernel, , + callout_start, c, 0, 0, 0, 0); + c_func(c_arg); + SDT_PROBE(callout_execute, kernel, , + callout_end, c, 0, 0, 0, 0); + THREAD_SLEEPING_OK(); +#ifdef DIAGNOSTIC + binuptime(&bt2); + bintime_sub(&bt2, &bt1); + if (bt2.frac > maxdt) { + if (lastfunc != c_func || + bt2.frac > maxdt * 2) { + bintime2timespec(&bt2, &ts2); + printf( + "Expensive timeout(9) function: %p(%p) %jd.%09ld s\n", + c_func, c_arg, + (intmax_t)ts2.tv_sec, + ts2.tv_nsec); + } + maxdt = bt2.frac; + lastfunc = c_func; + } +#endif + CTR1(KTR_CALLOUT, "callout %p finished", c); + if ((c_flags & CALLOUT_RETURNUNLOCKED) == 0) + class->lc_unlock(c_lock); + skip: + CC_LOCK(cc); + /* + * If the current callout is locally + * allocated (from timeout(9)) + * then put it on the freelist. + * + * Note: we need to check the cached + * copy of c_flags because if it was not + * local, then it's not safe to deref the + * callout pointer. + */ + if (c_flags & CALLOUT_LOCAL_ALLOC) { + KASSERT(c->c_flags == + CALLOUT_LOCAL_ALLOC, + ("corrupted callout")); + c->c_func = NULL; + SLIST_INSERT_HEAD(&cc->cc_callfree, c, + c_links.sle); + } + cc->cc_curr = NULL; + if (cc->cc_waiting) { + /* + * There is someone waiting + * for the callout to complete. + */ + cc->cc_waiting = 0; + CC_UNLOCK(cc); + pthread_cond_broadcast(&callout_cv); + CC_LOCK(cc); + } + steps = 0; + c = cc->cc_next; + } + } + } + avg_depth += (depth * 1000 - avg_depth) >> 8; + avg_mpcalls += (mpcalls * 1000 - avg_mpcalls) >> 8; + avg_lockcalls += (lockcalls * 1000 - avg_lockcalls) >> 8; + avg_gcalls += (gcalls * 1000 - avg_gcalls) >> 8; + cc->cc_next = NULL; + CC_UNLOCK(cc); +} + /* * timeout -- * Execute a function after a specified length of time. @@ -129,12 +520,134 @@ timeout(ftn, arg, to_ticks) return (handle); } +void +untimeout(ftn, arg, handle) + timeout_t *ftn; + void *arg; + struct callout_handle handle; +{ + struct callout_cpu *cc; + /* + * Check for a handle that was initialized + * by callout_handle_init, but never used + * for a real timeout. + */ + if (handle.callout == NULL) + return; + + cc = callout_lock(handle.callout); + if (handle.callout->c_func == ftn && handle.callout->c_arg == arg) + callout_stop(handle.callout); + CC_UNLOCK(cc); +} + +void +callout_handle_init(struct callout_handle *handle) +{ + handle->callout = NULL; +} + +/* + * New interface; clients allocate their own callout structures. + * + * callout_reset() - establish or change a timeout + * callout_stop() - disestablish a timeout + * callout_init() - initialize a callout structure so that it can + * safely be passed to callout_reset() and callout_stop() + * + * <sys/callout.h> defines three convenience macros: + * + * callout_active() - returns truth if callout has not been stopped, + * drained, or deactivated since the last time the callout was + * reset. + * callout_pending() - returns truth if callout is still waiting for timeout + * callout_deactivate() - marks the callout as having been serviced + */ int callout_reset_on(struct callout *c, int to_ticks, void (*ftn)(void *), void *arg, int cpu) { - + struct callout_cpu *cc; + int cancelled = 0; + + /* + * Don't allow migration of pre-allocated callouts lest they + * become unbalanced. + */ + if (c->c_flags & CALLOUT_LOCAL_ALLOC) + cpu = c->c_cpu; +retry: + cc = callout_lock(c); + if (cc->cc_curr == c) { + /* + * We're being asked to reschedule a callout which is + * currently in progress. If there is a lock then we + * can cancel the callout if it has not really started. + */ + if (c->c_lock != NULL && !cc->cc_cancel) + cancelled = cc->cc_cancel = 1; + if (cc->cc_waiting) { + /* + * Someone has called callout_drain to kill this + * callout. Don't reschedule. + */ + CTR4(KTR_CALLOUT, "%s %p func %p arg %p", + cancelled ? "cancelled" : "failed to cancel", + c, c->c_func, c->c_arg); + CC_UNLOCK(cc); + return (cancelled); + } + } + if (c->c_flags & CALLOUT_PENDING) { + if (cc->cc_next == c) { + cc->cc_next = TAILQ_NEXT(c, c_links.tqe); + } + TAILQ_REMOVE(&cc->cc_callwheel[c->c_time & callwheelmask], c, + c_links.tqe); + + cancelled = 1; + c->c_flags &= ~(CALLOUT_ACTIVE | CALLOUT_PENDING); + } + /* + * If the lock must migrate we have to check the state again as + * we can't hold both the new and old locks simultaneously. + */ + if (c->c_cpu != cpu) { + c->c_cpu = cpu; + CC_UNLOCK(cc); + goto retry; + } + + if (to_ticks <= 0) + to_ticks = 1; + + c->c_arg = arg; + c->c_flags |= (CALLOUT_ACTIVE | CALLOUT_PENDING); + c->c_func = ftn; + c->c_time = ticks + to_ticks; + TAILQ_INSERT_TAIL(&cc->cc_callwheel[c->c_time & callwheelmask], + c, c_links.tqe); + CTR5(KTR_CALLOUT, "%sscheduled %p func %p arg %p in %d", + cancelled ? "re" : "", c, c->c_func, c->c_arg, to_ticks); + CC_UNLOCK(cc); + + return (cancelled); +} + +/* + * Common idioms that can be optimized in the future. + */ +int +callout_schedule_on(struct callout *c, int to_ticks, int cpu) +{ + return callout_reset_on(c, to_ticks, c->c_func, c->c_arg, cpu); +} + +int +callout_schedule(struct callout *c, int to_ticks) +{ + return callout_reset_on(c, to_ticks, c->c_func, c->c_arg, c->c_cpu); } int @@ -142,9 +655,95 @@ _callout_stop_safe(c, safe) struct callout *c; int safe; { - -} + struct callout_cpu *cc; + struct lock_class *class; + int use_lock, sq_locked; + + /* + * Some old subsystems don't hold Giant while running a callout_stop(), + * so just discard this check for the moment. + */ + if (!safe && c->c_lock != NULL) { + if (c->c_lock == &Giant.lock_object) + use_lock = mtx_owned(&Giant); + else { + use_lock = 1; + class = LOCK_CLASS(c->c_lock); + class->lc_assert(c->c_lock, LA_XLOCKED); + } + } else + use_lock = 0; + + sq_locked = 0; +again: + cc = callout_lock(c); + /* + * If the callout isn't pending, it's not on the queue, so + * don't attempt to remove it from the queue. We can try to + * stop it by other means however. + */ + if (!(c->c_flags & CALLOUT_PENDING)) { + c->c_flags &= ~CALLOUT_ACTIVE; + + /* + * If it wasn't on the queue and it isn't the current + * callout, then we can't stop it, so just bail. + */ + if (cc->cc_curr != c) { + CTR3(KTR_CALLOUT, "failed to stop %p func %p arg %p", + c, c->c_func, c->c_arg); + CC_UNLOCK(cc); + return (0); + } + + if (safe) { + /* + * The current callout is running (or just + * about to run) and blocking is allowed, so + * just wait for the current invocation to + * finish. + */ + while (cc->cc_curr == c) { + pthread_cond_wait(&callout_cv, &cc->cc_lock); + } + } else if (use_lock && !cc->cc_cancel) { + /* + * The current callout is waiting for its + * lock which we hold. Cancel the callout + * and return. After our caller drops the + * lock, the callout will be skipped in + * softclock(). + */ + cc->cc_cancel = 1; + CTR3(KTR_CALLOUT, "cancelled %p func %p arg %p", + c, c->c_func, c->c_arg); + CC_UNLOCK(cc); + return (1); + } + CTR3(KTR_CALLOUT, "failed to stop %p func %p arg %p", + c, c->c_func, c->c_arg); + CC_UNLOCK(cc); + return (0); + } + + c->c_flags &= ~(CALLOUT_ACTIVE | CALLOUT_PENDING); + + if (cc->cc_next == c) { + cc->cc_next = TAILQ_NEXT(c, c_links.tqe); + } + TAILQ_REMOVE(&cc->cc_callwheel[c->c_time & callwheelmask], c, + c_links.tqe); + CTR3(KTR_CALLOUT, "cancelled %p func %p arg %p", + c, c->c_func, c->c_arg); + + if (c->c_flags & CALLOUT_LOCAL_ALLOC) { + c->c_func = NULL; + SLIST_INSERT_HEAD(&cc->cc_callfree, c, c_links.sle); + } + CC_UNLOCK(cc); + return (1); +} void callout_init(c, mpsafe) @@ -168,4 +767,16 @@ _callout_init_lock(c, lock, flags) struct lock_object *lock; int flags; { + bzero(c, sizeof *c); + c->c_lock = lock; + KASSERT((flags & ~(CALLOUT_RETURNUNLOCKED | CALLOUT_SHAREDLOCK)) == 0, + ("callout_init_lock: bad flags %d", flags)); + KASSERT(lock != NULL || (flags & CALLOUT_RETURNUNLOCKED) == 0, + ("callout_init_lock: CALLOUT_RETURNUNLOCKED with no lock")); + KASSERT(lock == NULL || !(LOCK_CLASS(lock)->lc_flags & + (LC_SPINLOCK | LC_SLEEPABLE)), ("%s: invalid lock class", + __func__)); + c->c_flags = flags & (CALLOUT_RETURNUNLOCKED | CALLOUT_SHAREDLOCK); + c->c_cpu = timeout_cpu; } +
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