diff --git a/sys/kern/kern_fail.c b/sys/kern/kern_fail.c index b0a166d79e0d..ec466ddcb34d 100644 --- a/sys/kern/kern_fail.c +++ b/sys/kern/kern_fail.c @@ -1,1122 +1,1128 @@ /*- * Copyright (c) 2009 Isilon Inc http://www.isilon.com/ * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ /** * @file * * fail(9) Facility. * * @ingroup failpoint_private */ /** * @defgroup failpoint fail(9) Facility * * Failpoints allow for injecting fake errors into running code on the fly, * without modifying code or recompiling with flags. Failpoints are always * present, and are very efficient when disabled. Failpoints are described * in man fail(9). */ /** * @defgroup failpoint_private Private fail(9) Implementation functions * * Private implementations for the actual failpoint code. * * @ingroup failpoint */ /** * @addtogroup failpoint_private * @{ */ #include __FBSDID("$FreeBSD$"); +#include "opt_stack.h" + #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef ILOG_DEFINE_FOR_FILE ILOG_DEFINE_FOR_FILE(L_ISI_FAIL_POINT, L_ILOG, fail_point); #endif static MALLOC_DEFINE(M_FAIL_POINT, "Fail Points", "fail points system"); #define fp_free(ptr) free(ptr, M_FAIL_POINT) #define fp_malloc(size, flags) malloc((size), M_FAIL_POINT, (flags)) #define fs_free(ptr) fp_free(ptr) #define fs_malloc() fp_malloc(sizeof(struct fail_point_setting), \ M_WAITOK | M_ZERO) /** * These define the wchans that are used for sleeping, pausing respectively. * They are chosen arbitrarily but need to be distinct to the failpoint and * the sleep/pause distinction. */ #define FP_SLEEP_CHANNEL(fp) (void*)(fp) #define FP_PAUSE_CHANNEL(fp) __DEVOLATILE(void*, &fp->fp_setting) /** * Don't allow more than this many entries in a fail point set by sysctl. * The 99.99...% case is to have 1 entry. I can't imagine having this many * entries, so it should not limit us. Saves on re-mallocs while holding * a non-sleepable lock. */ #define FP_MAX_ENTRY_COUNT 20 /* Used to drain sbufs to the sysctl output */ int fail_sysctl_drain_func(void *, const char *, int); /* Head of tailq of struct fail_point_entry */ TAILQ_HEAD(fail_point_entry_queue, fail_point_entry); /** * fp entries garbage list; outstanding entries are cleaned up in the * garbage collector */ STAILQ_HEAD(fail_point_setting_garbage, fail_point_setting); static struct fail_point_setting_garbage fp_setting_garbage = STAILQ_HEAD_INITIALIZER(fp_setting_garbage); static struct mtx mtx_garbage_list; MTX_SYSINIT(mtx_garbage_list, &mtx_garbage_list, "fail point garbage mtx", MTX_SPIN); static struct sx sx_fp_set; SX_SYSINIT(sx_fp_set, &sx_fp_set, "fail point set sx"); /** * Failpoint types. * Don't change these without changing fail_type_strings in fail.c. * @ingroup failpoint_private */ enum fail_point_t { FAIL_POINT_OFF, /**< don't fail */ FAIL_POINT_PANIC, /**< panic */ FAIL_POINT_RETURN, /**< return an errorcode */ FAIL_POINT_BREAK, /**< break into the debugger */ FAIL_POINT_PRINT, /**< print a message */ FAIL_POINT_SLEEP, /**< sleep for some msecs */ FAIL_POINT_PAUSE, /**< sleep until failpoint is set to off */ FAIL_POINT_YIELD, /**< yield the cpu */ FAIL_POINT_DELAY, /**< busy wait the cpu */ FAIL_POINT_NUMTYPES, FAIL_POINT_INVALID = -1 }; static struct { const char *name; int nmlen; } fail_type_strings[] = { #define FP_TYPE_NM_LEN(s) { s, sizeof(s) - 1 } [FAIL_POINT_OFF] = FP_TYPE_NM_LEN("off"), [FAIL_POINT_PANIC] = FP_TYPE_NM_LEN("panic"), [FAIL_POINT_RETURN] = FP_TYPE_NM_LEN("return"), [FAIL_POINT_BREAK] = FP_TYPE_NM_LEN("break"), [FAIL_POINT_PRINT] = FP_TYPE_NM_LEN("print"), [FAIL_POINT_SLEEP] = FP_TYPE_NM_LEN("sleep"), [FAIL_POINT_PAUSE] = FP_TYPE_NM_LEN("pause"), [FAIL_POINT_YIELD] = FP_TYPE_NM_LEN("yield"), [FAIL_POINT_DELAY] = FP_TYPE_NM_LEN("delay"), }; #define FE_COUNT_UNTRACKED (INT_MIN) /** * Internal structure tracking a single term of a complete failpoint. * @ingroup failpoint_private */ struct fail_point_entry { volatile bool fe_stale; enum fail_point_t fe_type; /**< type of entry */ int fe_arg; /**< argument to type (e.g. return value) */ int fe_prob; /**< likelihood of firing in millionths */ int fe_count; /**< number of times to fire, -1 means infinite */ pid_t fe_pid; /**< only fail for this process */ struct fail_point *fe_parent; /**< backpointer to fp */ TAILQ_ENTRY(fail_point_entry) fe_entries; /**< next entry ptr */ }; struct fail_point_setting { STAILQ_ENTRY(fail_point_setting) fs_garbage_link; struct fail_point_entry_queue fp_entry_queue; struct fail_point * fs_parent; struct mtx feq_mtx; /* Gives fail_point_pause something to do. */ }; /** * Defines stating the equivalent of probablilty one (100%) */ enum { PROB_MAX = 1000000, /* probability between zero and this number */ PROB_DIGITS = 6 /* number of zero's in above number */ }; /* Get a ref on an fp's fp_setting */ static inline struct fail_point_setting *fail_point_setting_get_ref( struct fail_point *fp); /* Release a ref on an fp_setting */ static inline void fail_point_setting_release_ref(struct fail_point *fp); /* Allocate and initialize a struct fail_point_setting */ static struct fail_point_setting *fail_point_setting_new(struct fail_point *); /* Free a struct fail_point_setting */ static void fail_point_setting_destroy(struct fail_point_setting *fp_setting); /* Allocate and initialize a struct fail_point_entry */ static struct fail_point_entry *fail_point_entry_new(struct fail_point_setting *); /* Free a struct fail_point_entry */ static void fail_point_entry_destroy(struct fail_point_entry *fp_entry); /* Append fp setting to garbage list */ static inline void fail_point_setting_garbage_append( struct fail_point_setting *fp_setting); /* Swap fp's setting with fp_setting_new */ static inline struct fail_point_setting * fail_point_swap_settings(struct fail_point *fp, struct fail_point_setting *fp_setting_new); /* Free up any zero-ref setting in the garbage queue */ static void fail_point_garbage_collect(void); /* If this fail point's setting are empty, then swap it out to NULL. */ static inline void fail_point_eval_swap_out(struct fail_point *fp, struct fail_point_setting *fp_setting); bool fail_point_is_off(struct fail_point *fp) { bool return_val; struct fail_point_setting *fp_setting; struct fail_point_entry *ent; return_val = true; fp_setting = fail_point_setting_get_ref(fp); if (fp_setting != NULL) { TAILQ_FOREACH(ent, &fp_setting->fp_entry_queue, fe_entries) { if (!ent->fe_stale) { return_val = false; break; } } } fail_point_setting_release_ref(fp); return (return_val); } /* Allocate and initialize a struct fail_point_setting */ static struct fail_point_setting * fail_point_setting_new(struct fail_point *fp) { struct fail_point_setting *fs_new; fs_new = fs_malloc(); fs_new->fs_parent = fp; TAILQ_INIT(&fs_new->fp_entry_queue); mtx_init(&fs_new->feq_mtx, "fail point entries", NULL, MTX_SPIN); fail_point_setting_garbage_append(fs_new); return (fs_new); } /* Free a struct fail_point_setting */ static void fail_point_setting_destroy(struct fail_point_setting *fp_setting) { struct fail_point_entry *ent; while (!TAILQ_EMPTY(&fp_setting->fp_entry_queue)) { ent = TAILQ_FIRST(&fp_setting->fp_entry_queue); TAILQ_REMOVE(&fp_setting->fp_entry_queue, ent, fe_entries); fail_point_entry_destroy(ent); } fs_free(fp_setting); } /* Allocate and initialize a struct fail_point_entry */ static struct fail_point_entry * fail_point_entry_new(struct fail_point_setting *fp_setting) { struct fail_point_entry *fp_entry; fp_entry = fp_malloc(sizeof(struct fail_point_entry), M_WAITOK | M_ZERO); fp_entry->fe_parent = fp_setting->fs_parent; fp_entry->fe_prob = PROB_MAX; fp_entry->fe_pid = NO_PID; fp_entry->fe_count = FE_COUNT_UNTRACKED; TAILQ_INSERT_TAIL(&fp_setting->fp_entry_queue, fp_entry, fe_entries); return (fp_entry); } /* Free a struct fail_point_entry */ static void fail_point_entry_destroy(struct fail_point_entry *fp_entry) { fp_free(fp_entry); } /* Get a ref on an fp's fp_setting */ static inline struct fail_point_setting * fail_point_setting_get_ref(struct fail_point *fp) { struct fail_point_setting *fp_setting; /* Invariant: if we have a ref, our pointer to fp_setting is safe */ atomic_add_acq_32(&fp->fp_ref_cnt, 1); fp_setting = fp->fp_setting; return (fp_setting); } /* Release a ref on an fp_setting */ static inline void fail_point_setting_release_ref(struct fail_point *fp) { KASSERT(&fp->fp_ref_cnt > 0, ("Attempting to deref w/no refs")); atomic_subtract_rel_32(&fp->fp_ref_cnt, 1); } /* Append fp entries to fp garbage list */ static inline void fail_point_setting_garbage_append(struct fail_point_setting *fp_setting) { mtx_lock_spin(&mtx_garbage_list); STAILQ_INSERT_TAIL(&fp_setting_garbage, fp_setting, fs_garbage_link); mtx_unlock_spin(&mtx_garbage_list); } /* Swap fp's entries with fp_setting_new */ static struct fail_point_setting * fail_point_swap_settings(struct fail_point *fp, struct fail_point_setting *fp_setting_new) { struct fail_point_setting *fp_setting_old; fp_setting_old = fp->fp_setting; fp->fp_setting = fp_setting_new; return (fp_setting_old); } static inline void fail_point_eval_swap_out(struct fail_point *fp, struct fail_point_setting *fp_setting) { /* We may have already been swapped out and replaced; ignore. */ if (fp->fp_setting == fp_setting) fail_point_swap_settings(fp, NULL); } /* Free up any zero-ref entries in the garbage queue */ static void fail_point_garbage_collect() { struct fail_point_setting *fs_current, *fs_next; struct fail_point_setting_garbage fp_ents_free_list; /** * We will transfer the entries to free to fp_ents_free_list while holding * the spin mutex, then free it after we drop the lock. This avoids * triggering witness due to sleepable mutexes in the memory * allocator. */ STAILQ_INIT(&fp_ents_free_list); mtx_lock_spin(&mtx_garbage_list); STAILQ_FOREACH_SAFE(fs_current, &fp_setting_garbage, fs_garbage_link, fs_next) { if (fs_current->fs_parent->fp_setting != fs_current && fs_current->fs_parent->fp_ref_cnt == 0) { STAILQ_REMOVE(&fp_setting_garbage, fs_current, fail_point_setting, fs_garbage_link); STAILQ_INSERT_HEAD(&fp_ents_free_list, fs_current, fs_garbage_link); } } mtx_unlock_spin(&mtx_garbage_list); STAILQ_FOREACH_SAFE(fs_current, &fp_ents_free_list, fs_garbage_link, fs_next) fail_point_setting_destroy(fs_current); } /* Drain out all refs from this fail point */ static inline void fail_point_drain(struct fail_point *fp, int expected_ref) { struct fail_point_setting *entries; entries = fail_point_swap_settings(fp, NULL); /** * We have unpaused all threads; so we will wait no longer * than the time taken for the longest remaining sleep, or * the length of time of a long-running code block. */ while (fp->fp_ref_cnt > expected_ref) { wakeup(FP_PAUSE_CHANNEL(fp)); tsleep(&fp, PWAIT, "fail_point_drain", hz / 100); } fail_point_swap_settings(fp, entries); } static inline void fail_point_pause(struct fail_point *fp, enum fail_point_return_code *pret, struct mtx *mtx_sleep) { if (fp->fp_pre_sleep_fn) fp->fp_pre_sleep_fn(fp->fp_pre_sleep_arg); msleep_spin(FP_PAUSE_CHANNEL(fp), mtx_sleep, "failpt", 0); if (fp->fp_post_sleep_fn) fp->fp_post_sleep_fn(fp->fp_post_sleep_arg); } static inline void fail_point_sleep(struct fail_point *fp, int msecs, enum fail_point_return_code *pret) { int timo; /* Convert from millisecs to ticks, rounding up */ timo = howmany(msecs * hz, 1000); if (timo > 0) { if (!(fp->fp_flags & FAIL_POINT_USE_TIMEOUT_PATH)) { if (fp->fp_pre_sleep_fn) fp->fp_pre_sleep_fn(fp->fp_pre_sleep_arg); tsleep(FP_SLEEP_CHANNEL(fp), PWAIT, "failpt", timo); if (fp->fp_post_sleep_fn) fp->fp_post_sleep_fn(fp->fp_post_sleep_arg); } else { if (fp->fp_pre_sleep_fn) fp->fp_pre_sleep_fn(fp->fp_pre_sleep_arg); timeout(fp->fp_post_sleep_fn, fp->fp_post_sleep_arg, timo); *pret = FAIL_POINT_RC_QUEUED; } } } static char *parse_fail_point(struct fail_point_setting *, char *); static char *parse_term(struct fail_point_setting *, char *); static char *parse_number(int *out_units, int *out_decimal, char *); static char *parse_type(struct fail_point_entry *, char *); /** * Initialize a fail_point. The name is formed in a printf-like fashion * from "fmt" and subsequent arguments. This function is generally used * for custom failpoints located at odd places in the sysctl tree, and is * not explicitly needed for standard in-line-declared failpoints. * * @ingroup failpoint */ void fail_point_init(struct fail_point *fp, const char *fmt, ...) { va_list ap; char *name; int n; fp->fp_setting = NULL; fp->fp_flags = 0; /* Figure out the size of the name. */ va_start(ap, fmt); n = vsnprintf(NULL, 0, fmt, ap); va_end(ap); /* Allocate the name and fill it in. */ name = fp_malloc(n + 1, M_WAITOK); if (name != NULL) { va_start(ap, fmt); vsnprintf(name, n + 1, fmt, ap); va_end(ap); } fp->fp_name = name; fp->fp_location = ""; fp->fp_flags |= FAIL_POINT_DYNAMIC_NAME; fp->fp_pre_sleep_fn = NULL; fp->fp_pre_sleep_arg = NULL; fp->fp_post_sleep_fn = NULL; fp->fp_post_sleep_arg = NULL; } /** * Free the resources held by a fail_point, and wake any paused threads. * Thou shalt not allow threads to hit this fail point after you enter this * function, nor shall you call this multiple times for a given fp. * @ingroup failpoint */ void fail_point_destroy(struct fail_point *fp) { fail_point_drain(fp, 0); if ((fp->fp_flags & FAIL_POINT_DYNAMIC_NAME) != 0) { fp_free(__DECONST(void *, fp->fp_name)); fp->fp_name = NULL; } fp->fp_flags = 0; sx_xlock(&sx_fp_set); fail_point_garbage_collect(); sx_xunlock(&sx_fp_set); } /** * This does the real work of evaluating a fail point. If the fail point tells * us to return a value, this function returns 1 and fills in 'return_value' * (return_value is allowed to be null). If the fail point tells us to panic, * we never return. Otherwise we just return 0 after doing some work, which * means "keep going". */ enum fail_point_return_code fail_point_eval_nontrivial(struct fail_point *fp, int *return_value) { bool execute = false; struct fail_point_entry *ent; struct fail_point_setting *fp_setting; enum fail_point_return_code ret; int cont; int count; int msecs; int usecs; ret = FAIL_POINT_RC_CONTINUE; cont = 0; /* don't continue by default */ fp_setting = fail_point_setting_get_ref(fp); if (fp_setting == NULL) goto abort; TAILQ_FOREACH(ent, &fp_setting->fp_entry_queue, fe_entries) { if (ent->fe_stale) continue; if (ent->fe_prob < PROB_MAX && ent->fe_prob < random() % PROB_MAX) continue; if (ent->fe_pid != NO_PID && ent->fe_pid != curproc->p_pid) continue; if (ent->fe_count != FE_COUNT_UNTRACKED) { count = ent->fe_count; while (count > 0) { if (atomic_cmpset_32(&ent->fe_count, count, count - 1)) { count--; execute = true; break; } count = ent->fe_count; } if (execute == false) /* We lost the race; consider the entry stale and bail now */ continue; if (count == 0) ent->fe_stale = true; } switch (ent->fe_type) { case FAIL_POINT_PANIC: panic("fail point %s panicking", fp->fp_name); /* NOTREACHED */ case FAIL_POINT_RETURN: if (return_value != NULL) *return_value = ent->fe_arg; ret = FAIL_POINT_RC_RETURN; break; case FAIL_POINT_BREAK: printf("fail point %s breaking to debugger\n", fp->fp_name); breakpoint(); break; case FAIL_POINT_PRINT: printf("fail point %s executing\n", fp->fp_name); cont = ent->fe_arg; break; case FAIL_POINT_SLEEP: msecs = ent->fe_arg; if (msecs) fail_point_sleep(fp, msecs, &ret); break; case FAIL_POINT_PAUSE: /** * Pausing is inherently strange with multiple * entries given our design. That is because some * entries could be unreachable, for instance in cases like: * pause->return. We can never reach the return entry. * The sysctl layer actually truncates all entries after * a pause for this reason. */ mtx_lock_spin(&fp_setting->feq_mtx); fail_point_pause(fp, &ret, &fp_setting->feq_mtx); mtx_unlock_spin(&fp_setting->feq_mtx); break; case FAIL_POINT_YIELD: kern_yield(-1); break; case FAIL_POINT_DELAY: usecs = ent->fe_arg; DELAY(usecs); break; default: break; } if (cont == 0) break; } if (fail_point_is_off(fp)) fail_point_eval_swap_out(fp, fp_setting); abort: fail_point_setting_release_ref(fp); return (ret); } /** * Translate internal fail_point structure into human-readable text. */ static void fail_point_get(struct fail_point *fp, struct sbuf *sb, bool verbose) { struct fail_point_entry *ent; struct fail_point_setting *fp_setting; struct fail_point_entry *fp_entry_cpy; int cnt_sleeping; int idx; int printed_entry_count; cnt_sleeping = 0; idx = 0; printed_entry_count = 0; fp_entry_cpy = fp_malloc(sizeof(struct fail_point_entry) * (FP_MAX_ENTRY_COUNT + 1), M_WAITOK); fp_setting = fail_point_setting_get_ref(fp); if (fp_setting != NULL) { TAILQ_FOREACH(ent, &fp_setting->fp_entry_queue, fe_entries) { if (ent->fe_stale) continue; KASSERT(printed_entry_count < FP_MAX_ENTRY_COUNT, ("FP entry list larger than allowed")); fp_entry_cpy[printed_entry_count] = *ent; ++printed_entry_count; } } fail_point_setting_release_ref(fp); /* This is our equivalent of a NULL terminator */ fp_entry_cpy[printed_entry_count].fe_type = FAIL_POINT_INVALID; while (idx < printed_entry_count) { ent = &fp_entry_cpy[idx]; ++idx; if (ent->fe_prob < PROB_MAX) { int decimal = ent->fe_prob % (PROB_MAX / 100); int units = ent->fe_prob / (PROB_MAX / 100); sbuf_printf(sb, "%d", units); if (decimal) { int digits = PROB_DIGITS - 2; while (!(decimal % 10)) { digits--; decimal /= 10; } sbuf_printf(sb, ".%0*d", digits, decimal); } sbuf_printf(sb, "%%"); } if (ent->fe_count >= 0) sbuf_printf(sb, "%d*", ent->fe_count); sbuf_printf(sb, "%s", fail_type_strings[ent->fe_type].name); if (ent->fe_arg) sbuf_printf(sb, "(%d)", ent->fe_arg); if (ent->fe_pid != NO_PID) sbuf_printf(sb, "[pid %d]", ent->fe_pid); if (TAILQ_NEXT(ent, fe_entries)) sbuf_printf(sb, "->"); } if (!printed_entry_count) sbuf_printf(sb, "off"); fp_free(fp_entry_cpy); if (verbose) { +#ifdef STACK /* Print number of sleeping threads. queue=0 is the argument * used by msleep when sending our threads to sleep. */ sbuf_printf(sb, "\nsleeping_thread_stacks = {\n"); sleepq_sbuf_print_stacks(sb, FP_SLEEP_CHANNEL(fp), 0, &cnt_sleeping); sbuf_printf(sb, "},\n"); +#endif sbuf_printf(sb, "sleeping_thread_count = %d,\n", cnt_sleeping); +#ifdef STACK sbuf_printf(sb, "paused_thread_stacks = {\n"); sleepq_sbuf_print_stacks(sb, FP_PAUSE_CHANNEL(fp), 0, &cnt_sleeping); sbuf_printf(sb, "},\n"); +#endif sbuf_printf(sb, "paused_thread_count = %d\n", cnt_sleeping); } } /** * Set an internal fail_point structure from a human-readable failpoint string * in a lock-safe manner. */ static int fail_point_set(struct fail_point *fp, char *buf) { struct fail_point_entry *ent, *ent_next; struct fail_point_setting *entries; bool should_wake_paused; bool should_truncate; int error; error = 0; should_wake_paused = false; should_truncate = false; /* Parse new entries. */ /** * ref protects our new malloc'd stuff from being garbage collected * before we link it. */ fail_point_setting_get_ref(fp); entries = fail_point_setting_new(fp); if (parse_fail_point(entries, buf) == NULL) { STAILQ_REMOVE(&fp_setting_garbage, entries, fail_point_setting, fs_garbage_link); fail_point_setting_destroy(entries); error = EINVAL; goto end; } /** * Transfer the entries we are going to keep to a new list. * Get rid of useless zero probability entries, and entries with hit * count 0. * If 'off' is present, and it has no hit count set, then all entries * after it are discarded since they are unreachable. */ TAILQ_FOREACH_SAFE(ent, &entries->fp_entry_queue, fe_entries, ent_next) { if (ent->fe_prob == 0 || ent->fe_count == 0) { printf("Discarding entry which cannot execute %s\n", fail_type_strings[ent->fe_type].name); TAILQ_REMOVE(&entries->fp_entry_queue, ent, fe_entries); fp_free(ent); continue; } else if (should_truncate) { printf("Discarding unreachable entry %s\n", fail_type_strings[ent->fe_type].name); TAILQ_REMOVE(&entries->fp_entry_queue, ent, fe_entries); fp_free(ent); continue; } if (ent->fe_type == FAIL_POINT_OFF) { should_wake_paused = true; if (ent->fe_count == FE_COUNT_UNTRACKED) { should_truncate = true; TAILQ_REMOVE(&entries->fp_entry_queue, ent, fe_entries); fp_free(ent); } } else if (ent->fe_type == FAIL_POINT_PAUSE) { should_truncate = true; } else if (ent->fe_type == FAIL_POINT_SLEEP && (fp->fp_flags & FAIL_POINT_NONSLEEPABLE)) { /** * If this fail point is annotated as being in a * non-sleepable ctx, convert sleep to delay and * convert the msec argument to usecs. */ printf("Sleep call request on fail point in " "non-sleepable context; using delay instead " "of sleep\n"); ent->fe_type = FAIL_POINT_DELAY; ent->fe_arg *= 1000; } } if (TAILQ_EMPTY(&entries->fp_entry_queue)) { entries = fail_point_swap_settings(fp, NULL); if (entries != NULL) wakeup(FP_PAUSE_CHANNEL(fp)); } else { if (should_wake_paused) wakeup(FP_PAUSE_CHANNEL(fp)); fail_point_swap_settings(fp, entries); } end: #ifdef IWARNING if (error) IWARNING("Failed to set %s %s to %s", fp->fp_name, fp->fp_location, buf); else INOTICE("Set %s %s to %s", fp->fp_name, fp->fp_location, buf); #endif /* IWARNING */ fail_point_setting_release_ref(fp); return (error); } #define MAX_FAIL_POINT_BUF 1023 /** * Handle kernel failpoint set/get. */ int fail_point_sysctl(SYSCTL_HANDLER_ARGS) { struct fail_point *fp; char *buf; struct sbuf *sb_check; struct sbuf sb; int error; error = 0; fp = arg1; buf = NULL; sb_check = sbuf_new(&sb, NULL, 1024, SBUF_AUTOEXTEND); if (sb_check != &sb) return (ENOMEM); sbuf_set_drain(&sb, (sbuf_drain_func *)fail_sysctl_drain_func, req); /* Setting */ /** * Lock protects any new entries from being garbage collected before we * can link them to the fail point. */ sx_xlock(&sx_fp_set); if (req->newptr) { if (req->newlen > MAX_FAIL_POINT_BUF) { error = EINVAL; goto out; } buf = fp_malloc(req->newlen + 1, M_WAITOK); error = SYSCTL_IN(req, buf, req->newlen); if (error) goto out; buf[req->newlen] = '\0'; error = fail_point_set(fp, buf); } fail_point_garbage_collect(); sx_xunlock(&sx_fp_set); /* Retrieving. */ fail_point_get(fp, &sb, false); out: sbuf_finish(&sb); sbuf_delete(&sb); if (buf) fp_free(buf); return (error); } int fail_point_sysctl_status(SYSCTL_HANDLER_ARGS) { struct fail_point *fp; struct sbuf sb, *sb_check; fp = arg1; sb_check = sbuf_new(&sb, NULL, 1024, SBUF_AUTOEXTEND); if (sb_check != &sb) return (ENOMEM); sbuf_set_drain(&sb, (sbuf_drain_func *)fail_sysctl_drain_func, req); /* Retrieving. */ fail_point_get(fp, &sb, true); sbuf_finish(&sb); sbuf_delete(&sb); /** * Lock protects any new entries from being garbage collected before we * can link them to the fail point. */ sx_xlock(&sx_fp_set); fail_point_garbage_collect(); sx_xunlock(&sx_fp_set); return (0); } int fail_sysctl_drain_func(void *sysctl_args, const char *buf, int len) { struct sysctl_req *sa; int error; sa = sysctl_args; error = SYSCTL_OUT(sa, buf, len); if (error == ENOMEM) return (-1); else return (len); } /** * Internal helper function to translate a human-readable failpoint string * into a internally-parsable fail_point structure. */ static char * parse_fail_point(struct fail_point_setting *ents, char *p) { /* :: * ( "->" )* */ uint8_t term_count; term_count = 1; p = parse_term(ents, p); if (p == NULL) return (NULL); while (*p != '\0') { term_count++; if (p[0] != '-' || p[1] != '>' || (p = parse_term(ents, p+2)) == NULL || term_count > FP_MAX_ENTRY_COUNT) return (NULL); } return (p); } /** * Internal helper function to parse an individual term from a failpoint. */ static char * parse_term(struct fail_point_setting *ents, char *p) { struct fail_point_entry *ent; ent = fail_point_entry_new(ents); /* * :: * ( ( "%") | ( "*" ) )* * * [ "(" ")" ] * [ "[pid " "]" ] */ /* ( ( "%") | ( "*" ) )* */ while (isdigit(*p) || *p == '.') { int units, decimal; p = parse_number(&units, &decimal, p); if (p == NULL) return (NULL); if (*p == '%') { if (units > 100) /* prevent overflow early */ units = 100; ent->fe_prob = units * (PROB_MAX / 100) + decimal; if (ent->fe_prob > PROB_MAX) ent->fe_prob = PROB_MAX; } else if (*p == '*') { if (!units || units < 0 || decimal) return (NULL); ent->fe_count = units; } else return (NULL); p++; } /* */ p = parse_type(ent, p); if (p == NULL) return (NULL); if (*p == '\0') return (p); /* [ "(" ")" ] */ if (*p != '(') return (p); p++; if (!isdigit(*p) && *p != '-') return (NULL); ent->fe_arg = strtol(p, &p, 0); if (*p++ != ')') return (NULL); /* [ "[pid " "]" ] */ #define PID_STRING "[pid " if (strncmp(p, PID_STRING, sizeof(PID_STRING) - 1) != 0) return (p); p += sizeof(PID_STRING) - 1; if (!isdigit(*p)) return (NULL); ent->fe_pid = strtol(p, &p, 0); if (*p++ != ']') return (NULL); return (p); } /** * Internal helper function to parse a numeric for a failpoint term. */ static char * parse_number(int *out_units, int *out_decimal, char *p) { char *old_p; /** * :: * [ "." ] | * "." */ /* whole part */ old_p = p; *out_units = strtol(p, &p, 10); if (p == old_p && *p != '.') return (NULL); /* fractional part */ *out_decimal = 0; if (*p == '.') { int digits = 0; p++; while (isdigit(*p)) { int digit = *p - '0'; if (digits < PROB_DIGITS - 2) *out_decimal = *out_decimal * 10 + digit; else if (digits == PROB_DIGITS - 2 && digit >= 5) (*out_decimal)++; digits++; p++; } if (!digits) /* need at least one digit after '.' */ return (NULL); while (digits++ < PROB_DIGITS - 2) /* add implicit zeros */ *out_decimal *= 10; } return (p); /* success */ } /** * Internal helper function to parse an individual type for a failpoint term. */ static char * parse_type(struct fail_point_entry *ent, char *beg) { enum fail_point_t type; int len; for (type = FAIL_POINT_OFF; type < FAIL_POINT_NUMTYPES; type++) { len = fail_type_strings[type].nmlen; if (strncmp(fail_type_strings[type].name, beg, len) == 0) { ent->fe_type = type; return (beg + len); } } return (NULL); } /* The fail point sysctl tree. */ SYSCTL_NODE(_debug, OID_AUTO, fail_point, CTLFLAG_RW, 0, "fail points"); /* Debugging/testing stuff for fail point */ static int sysctl_test_fail_point(SYSCTL_HANDLER_ARGS) { KFAIL_POINT_RETURN(DEBUG_FP, test_fail_point); return (0); } SYSCTL_OID(_debug_fail_point, OID_AUTO, test_trigger_fail_point, CTLTYPE_STRING | CTLFLAG_RD, NULL, 0, sysctl_test_fail_point, "A", "Trigger test fail points"); diff --git a/sys/kern/subr_sleepqueue.c b/sys/kern/subr_sleepqueue.c index 2c68454be453..921e362a0939 100644 --- a/sys/kern/subr_sleepqueue.c +++ b/sys/kern/subr_sleepqueue.c @@ -1,1364 +1,1367 @@ /*- * Copyright (c) 2004 John Baldwin * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ /* * Implementation of sleep queues used to hold queue of threads blocked on * a wait channel. Sleep queues different from turnstiles in that wait * channels are not owned by anyone, so there is no priority propagation. * Sleep queues can also provide a timeout and can also be interrupted by * signals. That said, there are several similarities between the turnstile * and sleep queue implementations. (Note: turnstiles were implemented * first.) For example, both use a hash table of the same size where each * bucket is referred to as a "chain" that contains both a spin lock and * a linked list of queues. An individual queue is located by using a hash * to pick a chain, locking the chain, and then walking the chain searching * for the queue. This means that a wait channel object does not need to * embed it's queue head just as locks do not embed their turnstile queue * head. Threads also carry around a sleep queue that they lend to the * wait channel when blocking. Just as in turnstiles, the queue includes * a free list of the sleep queues of other threads blocked on the same * wait channel in the case of multiple waiters. * * Some additional functionality provided by sleep queues include the * ability to set a timeout. The timeout is managed using a per-thread * callout that resumes a thread if it is asleep. A thread may also * catch signals while it is asleep (aka an interruptible sleep). The * signal code uses sleepq_abort() to interrupt a sleeping thread. Finally, * sleep queues also provide some extra assertions. One is not allowed to * mix the sleep/wakeup and cv APIs for a given wait channel. Also, one * must consistently use the same lock to synchronize with a wait channel, * though this check is currently only a warning for sleep/wakeup due to * pre-existing abuse of that API. The same lock must also be held when * awakening threads, though that is currently only enforced for condition * variables. */ #include __FBSDID("$FreeBSD$"); #include "opt_sleepqueue_profiling.h" #include "opt_ddb.h" #include "opt_sched.h" +#include "opt_stack.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef DDB #include #endif /* * Constants for the hash table of sleep queue chains. * SC_TABLESIZE must be a power of two for SC_MASK to work properly. */ #define SC_TABLESIZE 256 /* Must be power of 2. */ #define SC_MASK (SC_TABLESIZE - 1) #define SC_SHIFT 8 #define SC_HASH(wc) ((((uintptr_t)(wc) >> SC_SHIFT) ^ (uintptr_t)(wc)) & \ SC_MASK) #define SC_LOOKUP(wc) &sleepq_chains[SC_HASH(wc)] #define NR_SLEEPQS 2 /* * There two different lists of sleep queues. Both lists are connected * via the sq_hash entries. The first list is the sleep queue chain list * that a sleep queue is on when it is attached to a wait channel. The * second list is the free list hung off of a sleep queue that is attached * to a wait channel. * * Each sleep queue also contains the wait channel it is attached to, the * list of threads blocked on that wait channel, flags specific to the * wait channel, and the lock used to synchronize with a wait channel. * The flags are used to catch mismatches between the various consumers * of the sleep queue API (e.g. sleep/wakeup and condition variables). * The lock pointer is only used when invariants are enabled for various * debugging checks. * * Locking key: * c - sleep queue chain lock */ struct sleepqueue { TAILQ_HEAD(, thread) sq_blocked[NR_SLEEPQS]; /* (c) Blocked threads. */ u_int sq_blockedcnt[NR_SLEEPQS]; /* (c) N. of blocked threads. */ LIST_ENTRY(sleepqueue) sq_hash; /* (c) Chain and free list. */ LIST_HEAD(, sleepqueue) sq_free; /* (c) Free queues. */ void *sq_wchan; /* (c) Wait channel. */ int sq_type; /* (c) Queue type. */ #ifdef INVARIANTS struct lock_object *sq_lock; /* (c) Associated lock. */ #endif }; struct sleepqueue_chain { LIST_HEAD(, sleepqueue) sc_queues; /* List of sleep queues. */ struct mtx sc_lock; /* Spin lock for this chain. */ #ifdef SLEEPQUEUE_PROFILING u_int sc_depth; /* Length of sc_queues. */ u_int sc_max_depth; /* Max length of sc_queues. */ #endif }; #ifdef SLEEPQUEUE_PROFILING u_int sleepq_max_depth; static SYSCTL_NODE(_debug, OID_AUTO, sleepq, CTLFLAG_RD, 0, "sleepq profiling"); static SYSCTL_NODE(_debug_sleepq, OID_AUTO, chains, CTLFLAG_RD, 0, "sleepq chain stats"); SYSCTL_UINT(_debug_sleepq, OID_AUTO, max_depth, CTLFLAG_RD, &sleepq_max_depth, 0, "maxmimum depth achieved of a single chain"); static void sleepq_profile(const char *wmesg); static int prof_enabled; #endif static struct sleepqueue_chain sleepq_chains[SC_TABLESIZE]; static uma_zone_t sleepq_zone; /* * Prototypes for non-exported routines. */ static int sleepq_catch_signals(void *wchan, int pri); static int sleepq_check_signals(void); static int sleepq_check_timeout(void); #ifdef INVARIANTS static void sleepq_dtor(void *mem, int size, void *arg); #endif static int sleepq_init(void *mem, int size, int flags); static int sleepq_resume_thread(struct sleepqueue *sq, struct thread *td, int pri); static void sleepq_switch(void *wchan, int pri); static void sleepq_timeout(void *arg); SDT_PROBE_DECLARE(sched, , , sleep); SDT_PROBE_DECLARE(sched, , , wakeup); /* * Initialize SLEEPQUEUE_PROFILING specific sysctl nodes. * Note that it must happen after sleepinit() has been fully executed, so * it must happen after SI_SUB_KMEM SYSINIT() subsystem setup. */ #ifdef SLEEPQUEUE_PROFILING static void init_sleepqueue_profiling(void) { char chain_name[10]; struct sysctl_oid *chain_oid; u_int i; for (i = 0; i < SC_TABLESIZE; i++) { snprintf(chain_name, sizeof(chain_name), "%u", i); chain_oid = SYSCTL_ADD_NODE(NULL, SYSCTL_STATIC_CHILDREN(_debug_sleepq_chains), OID_AUTO, chain_name, CTLFLAG_RD, NULL, "sleepq chain stats"); SYSCTL_ADD_UINT(NULL, SYSCTL_CHILDREN(chain_oid), OID_AUTO, "depth", CTLFLAG_RD, &sleepq_chains[i].sc_depth, 0, NULL); SYSCTL_ADD_UINT(NULL, SYSCTL_CHILDREN(chain_oid), OID_AUTO, "max_depth", CTLFLAG_RD, &sleepq_chains[i].sc_max_depth, 0, NULL); } } SYSINIT(sleepqueue_profiling, SI_SUB_LOCK, SI_ORDER_ANY, init_sleepqueue_profiling, NULL); #endif /* * Early initialization of sleep queues that is called from the sleepinit() * SYSINIT. */ void init_sleepqueues(void) { int i; for (i = 0; i < SC_TABLESIZE; i++) { LIST_INIT(&sleepq_chains[i].sc_queues); mtx_init(&sleepq_chains[i].sc_lock, "sleepq chain", NULL, MTX_SPIN | MTX_RECURSE); } sleepq_zone = uma_zcreate("SLEEPQUEUE", sizeof(struct sleepqueue), #ifdef INVARIANTS NULL, sleepq_dtor, sleepq_init, NULL, UMA_ALIGN_CACHE, 0); #else NULL, NULL, sleepq_init, NULL, UMA_ALIGN_CACHE, 0); #endif thread0.td_sleepqueue = sleepq_alloc(); } /* * Get a sleep queue for a new thread. */ struct sleepqueue * sleepq_alloc(void) { return (uma_zalloc(sleepq_zone, M_WAITOK)); } /* * Free a sleep queue when a thread is destroyed. */ void sleepq_free(struct sleepqueue *sq) { uma_zfree(sleepq_zone, sq); } /* * Lock the sleep queue chain associated with the specified wait channel. */ void sleepq_lock(void *wchan) { struct sleepqueue_chain *sc; sc = SC_LOOKUP(wchan); mtx_lock_spin(&sc->sc_lock); } /* * Look up the sleep queue associated with a given wait channel in the hash * table locking the associated sleep queue chain. If no queue is found in * the table, NULL is returned. */ struct sleepqueue * sleepq_lookup(void *wchan) { struct sleepqueue_chain *sc; struct sleepqueue *sq; KASSERT(wchan != NULL, ("%s: invalid NULL wait channel", __func__)); sc = SC_LOOKUP(wchan); mtx_assert(&sc->sc_lock, MA_OWNED); LIST_FOREACH(sq, &sc->sc_queues, sq_hash) if (sq->sq_wchan == wchan) return (sq); return (NULL); } /* * Unlock the sleep queue chain associated with a given wait channel. */ void sleepq_release(void *wchan) { struct sleepqueue_chain *sc; sc = SC_LOOKUP(wchan); mtx_unlock_spin(&sc->sc_lock); } /* * Places the current thread on the sleep queue for the specified wait * channel. If INVARIANTS is enabled, then it associates the passed in * lock with the sleepq to make sure it is held when that sleep queue is * woken up. */ void sleepq_add(void *wchan, struct lock_object *lock, const char *wmesg, int flags, int queue) { struct sleepqueue_chain *sc; struct sleepqueue *sq; struct thread *td; td = curthread; sc = SC_LOOKUP(wchan); mtx_assert(&sc->sc_lock, MA_OWNED); MPASS(td->td_sleepqueue != NULL); MPASS(wchan != NULL); MPASS((queue >= 0) && (queue < NR_SLEEPQS)); /* If this thread is not allowed to sleep, die a horrible death. */ KASSERT(td->td_no_sleeping == 0, ("%s: td %p to sleep on wchan %p with sleeping prohibited", __func__, td, wchan)); /* Look up the sleep queue associated with the wait channel 'wchan'. */ sq = sleepq_lookup(wchan); /* * If the wait channel does not already have a sleep queue, use * this thread's sleep queue. Otherwise, insert the current thread * into the sleep queue already in use by this wait channel. */ if (sq == NULL) { #ifdef INVARIANTS int i; sq = td->td_sleepqueue; for (i = 0; i < NR_SLEEPQS; i++) { KASSERT(TAILQ_EMPTY(&sq->sq_blocked[i]), ("thread's sleep queue %d is not empty", i)); KASSERT(sq->sq_blockedcnt[i] == 0, ("thread's sleep queue %d count mismatches", i)); } KASSERT(LIST_EMPTY(&sq->sq_free), ("thread's sleep queue has a non-empty free list")); KASSERT(sq->sq_wchan == NULL, ("stale sq_wchan pointer")); sq->sq_lock = lock; #endif #ifdef SLEEPQUEUE_PROFILING sc->sc_depth++; if (sc->sc_depth > sc->sc_max_depth) { sc->sc_max_depth = sc->sc_depth; if (sc->sc_max_depth > sleepq_max_depth) sleepq_max_depth = sc->sc_max_depth; } #endif sq = td->td_sleepqueue; LIST_INSERT_HEAD(&sc->sc_queues, sq, sq_hash); sq->sq_wchan = wchan; sq->sq_type = flags & SLEEPQ_TYPE; } else { MPASS(wchan == sq->sq_wchan); MPASS(lock == sq->sq_lock); MPASS((flags & SLEEPQ_TYPE) == sq->sq_type); LIST_INSERT_HEAD(&sq->sq_free, td->td_sleepqueue, sq_hash); } thread_lock(td); TAILQ_INSERT_TAIL(&sq->sq_blocked[queue], td, td_slpq); sq->sq_blockedcnt[queue]++; td->td_sleepqueue = NULL; td->td_sqqueue = queue; td->td_wchan = wchan; td->td_wmesg = wmesg; if (flags & SLEEPQ_INTERRUPTIBLE) { td->td_flags |= TDF_SINTR; td->td_flags &= ~TDF_SLEEPABORT; } thread_unlock(td); } /* * Sets a timeout that will remove the current thread from the specified * sleep queue after timo ticks if the thread has not already been awakened. */ void sleepq_set_timeout_sbt(void *wchan, sbintime_t sbt, sbintime_t pr, int flags) { struct sleepqueue_chain *sc; struct thread *td; td = curthread; sc = SC_LOOKUP(wchan); mtx_assert(&sc->sc_lock, MA_OWNED); MPASS(TD_ON_SLEEPQ(td)); MPASS(td->td_sleepqueue == NULL); MPASS(wchan != NULL); callout_reset_sbt_on(&td->td_slpcallout, sbt, pr, sleepq_timeout, td, PCPU_GET(cpuid), flags | C_DIRECT_EXEC); } /* * Return the number of actual sleepers for the specified queue. */ u_int sleepq_sleepcnt(void *wchan, int queue) { struct sleepqueue *sq; KASSERT(wchan != NULL, ("%s: invalid NULL wait channel", __func__)); MPASS((queue >= 0) && (queue < NR_SLEEPQS)); sq = sleepq_lookup(wchan); if (sq == NULL) return (0); return (sq->sq_blockedcnt[queue]); } /* * Marks the pending sleep of the current thread as interruptible and * makes an initial check for pending signals before putting a thread * to sleep. Enters and exits with the thread lock held. Thread lock * may have transitioned from the sleepq lock to a run lock. */ static int sleepq_catch_signals(void *wchan, int pri) { struct sleepqueue_chain *sc; struct sleepqueue *sq; struct thread *td; struct proc *p; struct sigacts *ps; int sig, ret; td = curthread; p = curproc; sc = SC_LOOKUP(wchan); mtx_assert(&sc->sc_lock, MA_OWNED); MPASS(wchan != NULL); if ((td->td_pflags & TDP_WAKEUP) != 0) { td->td_pflags &= ~TDP_WAKEUP; ret = EINTR; thread_lock(td); goto out; } /* * See if there are any pending signals for this thread. If not * we can switch immediately. Otherwise do the signal processing * directly. */ thread_lock(td); if ((td->td_flags & (TDF_NEEDSIGCHK | TDF_NEEDSUSPCHK)) == 0) { sleepq_switch(wchan, pri); return (0); } thread_unlock(td); mtx_unlock_spin(&sc->sc_lock); CTR3(KTR_PROC, "sleepq catching signals: thread %p (pid %ld, %s)", (void *)td, (long)p->p_pid, td->td_name); PROC_LOCK(p); ps = p->p_sigacts; mtx_lock(&ps->ps_mtx); sig = cursig(td); if (sig == 0) { mtx_unlock(&ps->ps_mtx); ret = thread_suspend_check(1); MPASS(ret == 0 || ret == EINTR || ret == ERESTART); } else { if (SIGISMEMBER(ps->ps_sigintr, sig)) ret = EINTR; else ret = ERESTART; mtx_unlock(&ps->ps_mtx); } /* * Lock the per-process spinlock prior to dropping the PROC_LOCK * to avoid a signal delivery race. PROC_LOCK, PROC_SLOCK, and * thread_lock() are currently held in tdsendsignal(). */ PROC_SLOCK(p); mtx_lock_spin(&sc->sc_lock); PROC_UNLOCK(p); thread_lock(td); PROC_SUNLOCK(p); if (ret == 0) { sleepq_switch(wchan, pri); return (0); } out: /* * There were pending signals and this thread is still * on the sleep queue, remove it from the sleep queue. */ if (TD_ON_SLEEPQ(td)) { sq = sleepq_lookup(wchan); if (sleepq_resume_thread(sq, td, 0)) { #ifdef INVARIANTS /* * This thread hasn't gone to sleep yet, so it * should not be swapped out. */ panic("not waking up swapper"); #endif } } mtx_unlock_spin(&sc->sc_lock); MPASS(td->td_lock != &sc->sc_lock); return (ret); } /* * Switches to another thread if we are still asleep on a sleep queue. * Returns with thread lock. */ static void sleepq_switch(void *wchan, int pri) { struct sleepqueue_chain *sc; struct sleepqueue *sq; struct thread *td; td = curthread; sc = SC_LOOKUP(wchan); mtx_assert(&sc->sc_lock, MA_OWNED); THREAD_LOCK_ASSERT(td, MA_OWNED); /* * If we have a sleep queue, then we've already been woken up, so * just return. */ if (td->td_sleepqueue != NULL) { mtx_unlock_spin(&sc->sc_lock); return; } /* * If TDF_TIMEOUT is set, then our sleep has been timed out * already but we are still on the sleep queue, so dequeue the * thread and return. */ if (td->td_flags & TDF_TIMEOUT) { MPASS(TD_ON_SLEEPQ(td)); sq = sleepq_lookup(wchan); if (sleepq_resume_thread(sq, td, 0)) { #ifdef INVARIANTS /* * This thread hasn't gone to sleep yet, so it * should not be swapped out. */ panic("not waking up swapper"); #endif } mtx_unlock_spin(&sc->sc_lock); return; } #ifdef SLEEPQUEUE_PROFILING if (prof_enabled) sleepq_profile(td->td_wmesg); #endif MPASS(td->td_sleepqueue == NULL); sched_sleep(td, pri); thread_lock_set(td, &sc->sc_lock); SDT_PROBE0(sched, , , sleep); TD_SET_SLEEPING(td); mi_switch(SW_VOL | SWT_SLEEPQ, NULL); KASSERT(TD_IS_RUNNING(td), ("running but not TDS_RUNNING")); CTR3(KTR_PROC, "sleepq resume: thread %p (pid %ld, %s)", (void *)td, (long)td->td_proc->p_pid, (void *)td->td_name); } /* * Check to see if we timed out. */ static int sleepq_check_timeout(void) { struct thread *td; td = curthread; THREAD_LOCK_ASSERT(td, MA_OWNED); /* * If TDF_TIMEOUT is set, we timed out. */ if (td->td_flags & TDF_TIMEOUT) { td->td_flags &= ~TDF_TIMEOUT; return (EWOULDBLOCK); } /* * If TDF_TIMOFAIL is set, the timeout ran after we had * already been woken up. */ if (td->td_flags & TDF_TIMOFAIL) td->td_flags &= ~TDF_TIMOFAIL; /* * If callout_stop() fails, then the timeout is running on * another CPU, so synchronize with it to avoid having it * accidentally wake up a subsequent sleep. */ else if (_callout_stop_safe(&td->td_slpcallout, CS_MIGRBLOCK, NULL) == 0) { td->td_flags |= TDF_TIMEOUT; TD_SET_SLEEPING(td); mi_switch(SW_INVOL | SWT_SLEEPQTIMO, NULL); } return (0); } /* * Check to see if we were awoken by a signal. */ static int sleepq_check_signals(void) { struct thread *td; td = curthread; THREAD_LOCK_ASSERT(td, MA_OWNED); /* We are no longer in an interruptible sleep. */ if (td->td_flags & TDF_SINTR) td->td_flags &= ~TDF_SINTR; if (td->td_flags & TDF_SLEEPABORT) { td->td_flags &= ~TDF_SLEEPABORT; return (td->td_intrval); } return (0); } /* * Block the current thread until it is awakened from its sleep queue. */ void sleepq_wait(void *wchan, int pri) { struct thread *td; td = curthread; MPASS(!(td->td_flags & TDF_SINTR)); thread_lock(td); sleepq_switch(wchan, pri); thread_unlock(td); } /* * Block the current thread until it is awakened from its sleep queue * or it is interrupted by a signal. */ int sleepq_wait_sig(void *wchan, int pri) { int rcatch; int rval; rcatch = sleepq_catch_signals(wchan, pri); rval = sleepq_check_signals(); thread_unlock(curthread); if (rcatch) return (rcatch); return (rval); } /* * Block the current thread until it is awakened from its sleep queue * or it times out while waiting. */ int sleepq_timedwait(void *wchan, int pri) { struct thread *td; int rval; td = curthread; MPASS(!(td->td_flags & TDF_SINTR)); thread_lock(td); sleepq_switch(wchan, pri); rval = sleepq_check_timeout(); thread_unlock(td); return (rval); } /* * Block the current thread until it is awakened from its sleep queue, * it is interrupted by a signal, or it times out waiting to be awakened. */ int sleepq_timedwait_sig(void *wchan, int pri) { int rcatch, rvalt, rvals; rcatch = sleepq_catch_signals(wchan, pri); rvalt = sleepq_check_timeout(); rvals = sleepq_check_signals(); thread_unlock(curthread); if (rcatch) return (rcatch); if (rvals) return (rvals); return (rvalt); } /* * Returns the type of sleepqueue given a waitchannel. */ int sleepq_type(void *wchan) { struct sleepqueue *sq; int type; MPASS(wchan != NULL); sleepq_lock(wchan); sq = sleepq_lookup(wchan); if (sq == NULL) { sleepq_release(wchan); return (-1); } type = sq->sq_type; sleepq_release(wchan); return (type); } /* * Removes a thread from a sleep queue and makes it * runnable. */ static int sleepq_resume_thread(struct sleepqueue *sq, struct thread *td, int pri) { struct sleepqueue_chain *sc; MPASS(td != NULL); MPASS(sq->sq_wchan != NULL); MPASS(td->td_wchan == sq->sq_wchan); MPASS(td->td_sqqueue < NR_SLEEPQS && td->td_sqqueue >= 0); THREAD_LOCK_ASSERT(td, MA_OWNED); sc = SC_LOOKUP(sq->sq_wchan); mtx_assert(&sc->sc_lock, MA_OWNED); SDT_PROBE2(sched, , , wakeup, td, td->td_proc); /* Remove the thread from the queue. */ sq->sq_blockedcnt[td->td_sqqueue]--; TAILQ_REMOVE(&sq->sq_blocked[td->td_sqqueue], td, td_slpq); /* * Get a sleep queue for this thread. If this is the last waiter, * use the queue itself and take it out of the chain, otherwise, * remove a queue from the free list. */ if (LIST_EMPTY(&sq->sq_free)) { td->td_sleepqueue = sq; #ifdef INVARIANTS sq->sq_wchan = NULL; #endif #ifdef SLEEPQUEUE_PROFILING sc->sc_depth--; #endif } else td->td_sleepqueue = LIST_FIRST(&sq->sq_free); LIST_REMOVE(td->td_sleepqueue, sq_hash); td->td_wmesg = NULL; td->td_wchan = NULL; td->td_flags &= ~TDF_SINTR; CTR3(KTR_PROC, "sleepq_wakeup: thread %p (pid %ld, %s)", (void *)td, (long)td->td_proc->p_pid, td->td_name); /* Adjust priority if requested. */ MPASS(pri == 0 || (pri >= PRI_MIN && pri <= PRI_MAX)); if (pri != 0 && td->td_priority > pri && PRI_BASE(td->td_pri_class) == PRI_TIMESHARE) sched_prio(td, pri); /* * Note that thread td might not be sleeping if it is running * sleepq_catch_signals() on another CPU or is blocked on its * proc lock to check signals. There's no need to mark the * thread runnable in that case. */ if (TD_IS_SLEEPING(td)) { TD_CLR_SLEEPING(td); return (setrunnable(td)); } return (0); } #ifdef INVARIANTS /* * UMA zone item deallocator. */ static void sleepq_dtor(void *mem, int size, void *arg) { struct sleepqueue *sq; int i; sq = mem; for (i = 0; i < NR_SLEEPQS; i++) { MPASS(TAILQ_EMPTY(&sq->sq_blocked[i])); MPASS(sq->sq_blockedcnt[i] == 0); } } #endif /* * UMA zone item initializer. */ static int sleepq_init(void *mem, int size, int flags) { struct sleepqueue *sq; int i; bzero(mem, size); sq = mem; for (i = 0; i < NR_SLEEPQS; i++) { TAILQ_INIT(&sq->sq_blocked[i]); sq->sq_blockedcnt[i] = 0; } LIST_INIT(&sq->sq_free); return (0); } /* * Find the highest priority thread sleeping on a wait channel and resume it. */ int sleepq_signal(void *wchan, int flags, int pri, int queue) { struct sleepqueue *sq; struct thread *td, *besttd; int wakeup_swapper; CTR2(KTR_PROC, "sleepq_signal(%p, %d)", wchan, flags); KASSERT(wchan != NULL, ("%s: invalid NULL wait channel", __func__)); MPASS((queue >= 0) && (queue < NR_SLEEPQS)); sq = sleepq_lookup(wchan); if (sq == NULL) return (0); KASSERT(sq->sq_type == (flags & SLEEPQ_TYPE), ("%s: mismatch between sleep/wakeup and cv_*", __func__)); /* * Find the highest priority thread on the queue. If there is a * tie, use the thread that first appears in the queue as it has * been sleeping the longest since threads are always added to * the tail of sleep queues. */ besttd = NULL; TAILQ_FOREACH(td, &sq->sq_blocked[queue], td_slpq) { if (besttd == NULL || td->td_priority < besttd->td_priority) besttd = td; } MPASS(besttd != NULL); thread_lock(besttd); wakeup_swapper = sleepq_resume_thread(sq, besttd, pri); thread_unlock(besttd); return (wakeup_swapper); } /* * Resume all threads sleeping on a specified wait channel. */ int sleepq_broadcast(void *wchan, int flags, int pri, int queue) { struct sleepqueue *sq; struct thread *td, *tdn; int wakeup_swapper; CTR2(KTR_PROC, "sleepq_broadcast(%p, %d)", wchan, flags); KASSERT(wchan != NULL, ("%s: invalid NULL wait channel", __func__)); MPASS((queue >= 0) && (queue < NR_SLEEPQS)); sq = sleepq_lookup(wchan); if (sq == NULL) return (0); KASSERT(sq->sq_type == (flags & SLEEPQ_TYPE), ("%s: mismatch between sleep/wakeup and cv_*", __func__)); /* Resume all blocked threads on the sleep queue. */ wakeup_swapper = 0; TAILQ_FOREACH_SAFE(td, &sq->sq_blocked[queue], td_slpq, tdn) { thread_lock(td); if (sleepq_resume_thread(sq, td, pri)) wakeup_swapper = 1; thread_unlock(td); } return (wakeup_swapper); } /* * Time sleeping threads out. When the timeout expires, the thread is * removed from the sleep queue and made runnable if it is still asleep. */ static void sleepq_timeout(void *arg) { struct sleepqueue_chain *sc; struct sleepqueue *sq; struct thread *td; void *wchan; int wakeup_swapper; td = arg; wakeup_swapper = 0; CTR3(KTR_PROC, "sleepq_timeout: thread %p (pid %ld, %s)", (void *)td, (long)td->td_proc->p_pid, (void *)td->td_name); /* * First, see if the thread is asleep and get the wait channel if * it is. */ thread_lock(td); if (TD_IS_SLEEPING(td) && TD_ON_SLEEPQ(td)) { wchan = td->td_wchan; sc = SC_LOOKUP(wchan); THREAD_LOCKPTR_ASSERT(td, &sc->sc_lock); sq = sleepq_lookup(wchan); MPASS(sq != NULL); td->td_flags |= TDF_TIMEOUT; wakeup_swapper = sleepq_resume_thread(sq, td, 0); thread_unlock(td); if (wakeup_swapper) kick_proc0(); return; } /* * If the thread is on the SLEEPQ but isn't sleeping yet, it * can either be on another CPU in between sleepq_add() and * one of the sleepq_*wait*() routines or it can be in * sleepq_catch_signals(). */ if (TD_ON_SLEEPQ(td)) { td->td_flags |= TDF_TIMEOUT; thread_unlock(td); return; } /* * Now check for the edge cases. First, if TDF_TIMEOUT is set, * then the other thread has already yielded to us, so clear * the flag and resume it. If TDF_TIMEOUT is not set, then the * we know that the other thread is not on a sleep queue, but it * hasn't resumed execution yet. In that case, set TDF_TIMOFAIL * to let it know that the timeout has already run and doesn't * need to be canceled. */ if (td->td_flags & TDF_TIMEOUT) { MPASS(TD_IS_SLEEPING(td)); td->td_flags &= ~TDF_TIMEOUT; TD_CLR_SLEEPING(td); wakeup_swapper = setrunnable(td); } else td->td_flags |= TDF_TIMOFAIL; thread_unlock(td); if (wakeup_swapper) kick_proc0(); } /* * Resumes a specific thread from the sleep queue associated with a specific * wait channel if it is on that queue. */ void sleepq_remove(struct thread *td, void *wchan) { struct sleepqueue *sq; int wakeup_swapper; /* * Look up the sleep queue for this wait channel, then re-check * that the thread is asleep on that channel, if it is not, then * bail. */ MPASS(wchan != NULL); sleepq_lock(wchan); sq = sleepq_lookup(wchan); /* * We can not lock the thread here as it may be sleeping on a * different sleepq. However, holding the sleepq lock for this * wchan can guarantee that we do not miss a wakeup for this * channel. The asserts below will catch any false positives. */ if (!TD_ON_SLEEPQ(td) || td->td_wchan != wchan) { sleepq_release(wchan); return; } /* Thread is asleep on sleep queue sq, so wake it up. */ thread_lock(td); MPASS(sq != NULL); MPASS(td->td_wchan == wchan); wakeup_swapper = sleepq_resume_thread(sq, td, 0); thread_unlock(td); sleepq_release(wchan); if (wakeup_swapper) kick_proc0(); } /* * Abort a thread as if an interrupt had occurred. Only abort * interruptible waits (unfortunately it isn't safe to abort others). */ int sleepq_abort(struct thread *td, int intrval) { struct sleepqueue *sq; void *wchan; THREAD_LOCK_ASSERT(td, MA_OWNED); MPASS(TD_ON_SLEEPQ(td)); MPASS(td->td_flags & TDF_SINTR); MPASS(intrval == EINTR || intrval == ERESTART); /* * If the TDF_TIMEOUT flag is set, just leave. A * timeout is scheduled anyhow. */ if (td->td_flags & TDF_TIMEOUT) return (0); CTR3(KTR_PROC, "sleepq_abort: thread %p (pid %ld, %s)", (void *)td, (long)td->td_proc->p_pid, (void *)td->td_name); td->td_intrval = intrval; td->td_flags |= TDF_SLEEPABORT; /* * If the thread has not slept yet it will find the signal in * sleepq_catch_signals() and call sleepq_resume_thread. Otherwise * we have to do it here. */ if (!TD_IS_SLEEPING(td)) return (0); wchan = td->td_wchan; MPASS(wchan != NULL); sq = sleepq_lookup(wchan); MPASS(sq != NULL); /* Thread is asleep on sleep queue sq, so wake it up. */ return (sleepq_resume_thread(sq, td, 0)); } /* * Prints the stacks of all threads presently sleeping on wchan/queue to * the sbuf sb. Sets count_stacks_printed to the number of stacks actually * printed. Typically, this will equal the number of threads sleeping on the * queue, but may be less if sb overflowed before all stacks were printed. */ +#ifdef STACK int sleepq_sbuf_print_stacks(struct sbuf *sb, void *wchan, int queue, int *count_stacks_printed) { struct thread *td, *td_next; struct sleepqueue *sq; struct stack **st; struct sbuf **td_infos; int i, stack_idx, error, stacks_to_allocate; bool finished, partial_print; error = 0; finished = false; partial_print = false; KASSERT(wchan != NULL, ("%s: invalid NULL wait channel", __func__)); MPASS((queue >= 0) && (queue < NR_SLEEPQS)); stacks_to_allocate = 10; for (i = 0; i < 3 && !finished ; i++) { /* We cannot malloc while holding the queue's spinlock, so * we do our mallocs now, and hope it is enough. If it * isn't, we will free these, drop the lock, malloc more, * and try again, up to a point. After that point we will * give up and report ENOMEM. We also cannot write to sb * during this time since the client may have set the * SBUF_AUTOEXTEND flag on their sbuf, which could cause a * malloc as we print to it. So we defer actually printing * to sb until after we drop the spinlock. */ /* Where we will store the stacks. */ st = malloc(sizeof(struct stack *) * stacks_to_allocate, M_TEMP, M_WAITOK); for (stack_idx = 0; stack_idx < stacks_to_allocate; stack_idx++) st[stack_idx] = stack_create(); /* Where we will store the td name, tid, etc. */ td_infos = malloc(sizeof(struct sbuf *) * stacks_to_allocate, M_TEMP, M_WAITOK); for (stack_idx = 0; stack_idx < stacks_to_allocate; stack_idx++) td_infos[stack_idx] = sbuf_new(NULL, NULL, MAXCOMLEN + sizeof(struct thread *) * 2 + 40, SBUF_FIXEDLEN); sleepq_lock(wchan); sq = sleepq_lookup(wchan); if (sq == NULL) { /* This sleepq does not exist; exit and return ENOENT. */ error = ENOENT; finished = true; sleepq_release(wchan); goto loop_end; } stack_idx = 0; /* Save thread info */ TAILQ_FOREACH_SAFE(td, &sq->sq_blocked[queue], td_slpq, td_next) { if (stack_idx >= stacks_to_allocate) goto loop_end; /* Note the td_lock is equal to the sleepq_lock here. */ stack_save_td(st[stack_idx], td); sbuf_printf(td_infos[stack_idx], "%d: %s %p", td->td_tid, td->td_name, td); ++stack_idx; } finished = true; sleepq_release(wchan); /* Print the stacks */ for (i = 0; i < stack_idx; i++) { sbuf_finish(td_infos[i]); sbuf_printf(sb, "--- thread %s: ---\n", sbuf_data(td_infos[i])); stack_sbuf_print(sb, st[i]); sbuf_printf(sb, "\n"); error = sbuf_error(sb); if (error == 0) *count_stacks_printed = stack_idx; } loop_end: if (!finished) sleepq_release(wchan); for (stack_idx = 0; stack_idx < stacks_to_allocate; stack_idx++) stack_destroy(st[stack_idx]); for (stack_idx = 0; stack_idx < stacks_to_allocate; stack_idx++) sbuf_delete(td_infos[stack_idx]); free(st, M_TEMP); free(td_infos, M_TEMP); stacks_to_allocate *= 10; } if (!finished && error == 0) error = ENOMEM; return (error); } +#endif #ifdef SLEEPQUEUE_PROFILING #define SLEEPQ_PROF_LOCATIONS 1024 #define SLEEPQ_SBUFSIZE 512 struct sleepq_prof { LIST_ENTRY(sleepq_prof) sp_link; const char *sp_wmesg; long sp_count; }; LIST_HEAD(sqphead, sleepq_prof); struct sqphead sleepq_prof_free; struct sqphead sleepq_hash[SC_TABLESIZE]; static struct sleepq_prof sleepq_profent[SLEEPQ_PROF_LOCATIONS]; static struct mtx sleepq_prof_lock; MTX_SYSINIT(sleepq_prof_lock, &sleepq_prof_lock, "sleepq_prof", MTX_SPIN); static void sleepq_profile(const char *wmesg) { struct sleepq_prof *sp; mtx_lock_spin(&sleepq_prof_lock); if (prof_enabled == 0) goto unlock; LIST_FOREACH(sp, &sleepq_hash[SC_HASH(wmesg)], sp_link) if (sp->sp_wmesg == wmesg) goto done; sp = LIST_FIRST(&sleepq_prof_free); if (sp == NULL) goto unlock; sp->sp_wmesg = wmesg; LIST_REMOVE(sp, sp_link); LIST_INSERT_HEAD(&sleepq_hash[SC_HASH(wmesg)], sp, sp_link); done: sp->sp_count++; unlock: mtx_unlock_spin(&sleepq_prof_lock); return; } static void sleepq_prof_reset(void) { struct sleepq_prof *sp; int enabled; int i; mtx_lock_spin(&sleepq_prof_lock); enabled = prof_enabled; prof_enabled = 0; for (i = 0; i < SC_TABLESIZE; i++) LIST_INIT(&sleepq_hash[i]); LIST_INIT(&sleepq_prof_free); for (i = 0; i < SLEEPQ_PROF_LOCATIONS; i++) { sp = &sleepq_profent[i]; sp->sp_wmesg = NULL; sp->sp_count = 0; LIST_INSERT_HEAD(&sleepq_prof_free, sp, sp_link); } prof_enabled = enabled; mtx_unlock_spin(&sleepq_prof_lock); } static int enable_sleepq_prof(SYSCTL_HANDLER_ARGS) { int error, v; v = prof_enabled; error = sysctl_handle_int(oidp, &v, v, req); if (error) return (error); if (req->newptr == NULL) return (error); if (v == prof_enabled) return (0); if (v == 1) sleepq_prof_reset(); mtx_lock_spin(&sleepq_prof_lock); prof_enabled = !!v; mtx_unlock_spin(&sleepq_prof_lock); return (0); } static int reset_sleepq_prof_stats(SYSCTL_HANDLER_ARGS) { int error, v; v = 0; error = sysctl_handle_int(oidp, &v, 0, req); if (error) return (error); if (req->newptr == NULL) return (error); if (v == 0) return (0); sleepq_prof_reset(); return (0); } static int dump_sleepq_prof_stats(SYSCTL_HANDLER_ARGS) { struct sleepq_prof *sp; struct sbuf *sb; int enabled; int error; int i; error = sysctl_wire_old_buffer(req, 0); if (error != 0) return (error); sb = sbuf_new_for_sysctl(NULL, NULL, SLEEPQ_SBUFSIZE, req); sbuf_printf(sb, "\nwmesg\tcount\n"); enabled = prof_enabled; mtx_lock_spin(&sleepq_prof_lock); prof_enabled = 0; mtx_unlock_spin(&sleepq_prof_lock); for (i = 0; i < SC_TABLESIZE; i++) { LIST_FOREACH(sp, &sleepq_hash[i], sp_link) { sbuf_printf(sb, "%s\t%ld\n", sp->sp_wmesg, sp->sp_count); } } mtx_lock_spin(&sleepq_prof_lock); prof_enabled = enabled; mtx_unlock_spin(&sleepq_prof_lock); error = sbuf_finish(sb); sbuf_delete(sb); return (error); } SYSCTL_PROC(_debug_sleepq, OID_AUTO, stats, CTLTYPE_STRING | CTLFLAG_RD, NULL, 0, dump_sleepq_prof_stats, "A", "Sleepqueue profiling statistics"); SYSCTL_PROC(_debug_sleepq, OID_AUTO, reset, CTLTYPE_INT | CTLFLAG_RW, NULL, 0, reset_sleepq_prof_stats, "I", "Reset sleepqueue profiling statistics"); SYSCTL_PROC(_debug_sleepq, OID_AUTO, enable, CTLTYPE_INT | CTLFLAG_RW, NULL, 0, enable_sleepq_prof, "I", "Enable sleepqueue profiling"); #endif #ifdef DDB DB_SHOW_COMMAND(sleepq, db_show_sleepqueue) { struct sleepqueue_chain *sc; struct sleepqueue *sq; #ifdef INVARIANTS struct lock_object *lock; #endif struct thread *td; void *wchan; int i; if (!have_addr) return; /* * First, see if there is an active sleep queue for the wait channel * indicated by the address. */ wchan = (void *)addr; sc = SC_LOOKUP(wchan); LIST_FOREACH(sq, &sc->sc_queues, sq_hash) if (sq->sq_wchan == wchan) goto found; /* * Second, see if there is an active sleep queue at the address * indicated. */ for (i = 0; i < SC_TABLESIZE; i++) LIST_FOREACH(sq, &sleepq_chains[i].sc_queues, sq_hash) { if (sq == (struct sleepqueue *)addr) goto found; } db_printf("Unable to locate a sleep queue via %p\n", (void *)addr); return; found: db_printf("Wait channel: %p\n", sq->sq_wchan); db_printf("Queue type: %d\n", sq->sq_type); #ifdef INVARIANTS if (sq->sq_lock) { lock = sq->sq_lock; db_printf("Associated Interlock: %p - (%s) %s\n", lock, LOCK_CLASS(lock)->lc_name, lock->lo_name); } #endif db_printf("Blocked threads:\n"); for (i = 0; i < NR_SLEEPQS; i++) { db_printf("\nQueue[%d]:\n", i); if (TAILQ_EMPTY(&sq->sq_blocked[i])) db_printf("\tempty\n"); else TAILQ_FOREACH(td, &sq->sq_blocked[0], td_slpq) { db_printf("\t%p (tid %d, pid %d, \"%s\")\n", td, td->td_tid, td->td_proc->p_pid, td->td_name); } db_printf("(expected: %u)\n", sq->sq_blockedcnt[i]); } } /* Alias 'show sleepqueue' to 'show sleepq'. */ DB_SHOW_ALIAS(sleepqueue, db_show_sleepqueue); #endif diff --git a/sys/sys/sleepqueue.h b/sys/sys/sleepqueue.h index b607a5357e45..d59dc7e5a0a4 100644 --- a/sys/sys/sleepqueue.h +++ b/sys/sys/sleepqueue.h @@ -1,115 +1,117 @@ /*- * Copyright (c) 2004 John Baldwin * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * $FreeBSD$ */ #ifndef _SYS_SLEEPQUEUE_H_ #define _SYS_SLEEPQUEUE_H_ /* * Sleep queue interface. Sleep/wakeup, condition variables, and sx * locks use a sleep queue for the queue of threads blocked on a sleep * channel. * * A thread calls sleepq_lock() to lock the sleep queue chain associated * with a given wait channel. A thread can then call call sleepq_add() to * add themself onto a sleep queue and call one of the sleepq_wait() * functions to actually go to sleep. If a thread needs to abort a sleep * operation it should call sleepq_release() to unlock the associated sleep * queue chain lock. If the thread also needs to remove itself from a queue * it just enqueued itself on, it can use sleepq_remove() instead. * * If the thread only wishes to sleep for a limited amount of time, it can * call sleepq_set_timeout() after sleepq_add() to setup a timeout. It * should then use one of the sleepq_timedwait() functions to block. * * A thread is normally resumed from a sleep queue by either the * sleepq_signal() or sleepq_broadcast() functions. Sleepq_signal() wakes * the thread with the highest priority that is sleeping on the specified * wait channel. Sleepq_broadcast() wakes all threads that are sleeping * on the specified wait channel. A thread sleeping in an interruptible * sleep can be interrupted by calling sleepq_abort(). A thread can also * be removed from a specified sleep queue using the sleepq_remove() * function. Note that the sleep queue chain must first be locked via * sleepq_lock() before calling sleepq_abort(), sleepq_broadcast(), or * sleepq_signal(). These routines each return a boolean that will be true * if at least one swapped-out thread was resumed. In that case, the caller * is responsible for waking up the swapper by calling kick_proc0() after * releasing the sleep queue chain lock. * * Each thread allocates a sleep queue at thread creation via sleepq_alloc() * and releases it at thread destruction via sleepq_free(). Note that * a sleep queue is not tied to a specific thread and that the sleep queue * released at thread destruction may not be the same sleep queue that the * thread allocated when it was created. * * XXX: Some other parts of the kernel such as ithread sleeping may end up * using this interface as well (death to TDI_IWAIT!) */ struct lock_object; struct sleepqueue; struct thread; #ifdef _KERNEL #define SLEEPQ_TYPE 0x0ff /* Mask of sleep queue types. */ #define SLEEPQ_SLEEP 0x00 /* Used by sleep/wakeup. */ #define SLEEPQ_CONDVAR 0x01 /* Used for a cv. */ #define SLEEPQ_PAUSE 0x02 /* Used by pause. */ #define SLEEPQ_SX 0x03 /* Used by an sx lock. */ #define SLEEPQ_LK 0x04 /* Used by a lockmgr. */ #define SLEEPQ_INTERRUPTIBLE 0x100 /* Sleep is interruptible. */ void init_sleepqueues(void); int sleepq_abort(struct thread *td, int intrval); void sleepq_add(void *wchan, struct lock_object *lock, const char *wmesg, int flags, int queue); struct sleepqueue *sleepq_alloc(void); int sleepq_broadcast(void *wchan, int flags, int pri, int queue); void sleepq_free(struct sleepqueue *sq); void sleepq_lock(void *wchan); struct sleepqueue *sleepq_lookup(void *wchan); void sleepq_release(void *wchan); void sleepq_remove(struct thread *td, void *wchan); int sleepq_signal(void *wchan, int flags, int pri, int queue); void sleepq_set_timeout_sbt(void *wchan, sbintime_t sbt, sbintime_t pr, int flags); #define sleepq_set_timeout(wchan, timo) \ sleepq_set_timeout_sbt((wchan), tick_sbt * (timo), 0, C_HARDCLOCK) u_int sleepq_sleepcnt(void *wchan, int queue); int sleepq_timedwait(void *wchan, int pri); int sleepq_timedwait_sig(void *wchan, int pri); int sleepq_type(void *wchan); void sleepq_wait(void *wchan, int pri); int sleepq_wait_sig(void *wchan, int pri); -#include +#ifdef STACK +struct sbuf; int sleepq_sbuf_print_stacks(struct sbuf *sb, void *wchan, int queue, int *count_stacks_printed); +#endif #endif /* _KERNEL */ #endif /* !_SYS_SLEEPQUEUE_H_ */