/* * CDDL HEADER START * * The contents of this file are subject to the terms of the * Common Development and Distribution License (the "License"). * You may not use this file except in compliance with the License. * * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE * or http://www.opensolaris.org/os/licensing. * See the License for the specific language governing permissions * and limitations under the License. * * When distributing Covered Code, include this CDDL HEADER in each * file and include the License file at usr/src/OPENSOLARIS.LICENSE. * If applicable, add the following below this CDDL HEADER, with the * fields enclosed by brackets "[]" replaced with your own identifying * information: Portions Copyright [yyyy] [name of copyright owner] * * CDDL HEADER END */ /* * Copyright 2008 Sun Microsystems, Inc. All rights reserved. * Use is subject to license terms. */ #pragma ident "%Z%%M% %I% %E% SMI" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include struct kmem_cache *thread_cache; /* cache of free threads */ struct kmem_cache *lwp_cache; /* cache of free lwps */ struct kmem_cache *turnstile_cache; /* cache of free turnstiles */ /* * allthreads is only for use by kmem_readers. All kernel loops can use * the current thread as a start/end point. */ static kthread_t *allthreads = &t0; /* circular list of all threads */ static kcondvar_t reaper_cv; /* synchronization var */ kthread_t *thread_deathrow; /* circular list of reapable threads */ kthread_t *lwp_deathrow; /* circular list of reapable threads */ kmutex_t reaplock; /* protects lwp and thread deathrows */ int thread_reapcnt = 0; /* number of threads on deathrow */ int lwp_reapcnt = 0; /* number of lwps on deathrow */ int reaplimit = 16; /* delay reaping until reaplimit */ thread_free_lock_t *thread_free_lock; /* protects tick thread from reaper */ extern int nthread; id_t syscid; /* system scheduling class ID */ void *segkp_thread; /* cookie for segkp pool */ int lwp_cache_sz = 32; int t_cache_sz = 8; static kt_did_t next_t_id = 1; /* * Min/Max stack sizes for stack size parameters */ #define MAX_STKSIZE (32 * DEFAULTSTKSZ) #define MIN_STKSIZE DEFAULTSTKSZ /* * default_stksize overrides lwp_default_stksize if it is set. */ int default_stksize; int lwp_default_stksize; static zone_key_t zone_thread_key; /* * forward declarations for internal thread specific data (tsd) */ static void *tsd_realloc(void *, size_t, size_t); void thread_reaper(void); /*ARGSUSED*/ static int turnstile_constructor(void *buf, void *cdrarg, int kmflags) { bzero(buf, sizeof (turnstile_t)); return (0); } /*ARGSUSED*/ static void turnstile_destructor(void *buf, void *cdrarg) { turnstile_t *ts = buf; ASSERT(ts->ts_free == NULL); ASSERT(ts->ts_waiters == 0); ASSERT(ts->ts_inheritor == NULL); ASSERT(ts->ts_sleepq[0].sq_first == NULL); ASSERT(ts->ts_sleepq[1].sq_first == NULL); } void thread_init(void) { kthread_t *tp; extern char sys_name[]; extern void idle(); struct cpu *cpu = CPU; int i; kmutex_t *lp; mutex_init(&reaplock, NULL, MUTEX_SPIN, (void *)ipltospl(DISP_LEVEL)); thread_free_lock = kmem_alloc(sizeof (thread_free_lock_t) * THREAD_FREE_NUM, KM_SLEEP); for (i = 0; i < THREAD_FREE_NUM; i++) { lp = &thread_free_lock[i].tf_lock; mutex_init(lp, NULL, MUTEX_DEFAULT, NULL); } #if defined(__i386) || defined(__amd64) thread_cache = kmem_cache_create("thread_cache", sizeof (kthread_t), PTR24_ALIGN, NULL, NULL, NULL, NULL, NULL, 0); /* * "struct _klwp" includes a "struct pcb", which includes a * "struct fpu", which needs to be 16-byte aligned on amd64 * (and even on i386 for fxsave/fxrstor). */ lwp_cache = kmem_cache_create("lwp_cache", sizeof (klwp_t), 16, NULL, NULL, NULL, NULL, NULL, 0); #else /* * Allocate thread structures from static_arena. This prevents * issues where a thread tries to relocate its own thread * structure and touches it after the mapping has been suspended. */ thread_cache = kmem_cache_create("thread_cache", sizeof (kthread_t), PTR24_ALIGN, NULL, NULL, NULL, NULL, static_arena, 0); lwp_stk_cache_init(); lwp_cache = kmem_cache_create("lwp_cache", sizeof (klwp_t), 0, NULL, NULL, NULL, NULL, NULL, 0); #endif turnstile_cache = kmem_cache_create("turnstile_cache", sizeof (turnstile_t), 0, turnstile_constructor, turnstile_destructor, NULL, NULL, NULL, 0); label_init(); cred_init(); /* * Initialize various resource management facilities. */ rctl_init(); cpucaps_init(); /* * Zone_init() should be called before project_init() so that project ID * for the first project is initialized correctly. */ zone_init(); project_init(); brand_init(); kiconv_init(); task_init(); tcache_init(); pool_init(); curthread->t_ts = kmem_cache_alloc(turnstile_cache, KM_SLEEP); /* * Originally, we had two parameters to set default stack * size: one for lwp's (lwp_default_stksize), and one for * kernel-only threads (DEFAULTSTKSZ, a.k.a. _defaultstksz). * Now we have a third parameter that overrides both if it is * set to a legal stack size, called default_stksize. */ if (default_stksize == 0) { default_stksize = DEFAULTSTKSZ; } else if (default_stksize % PAGESIZE != 0 || default_stksize > MAX_STKSIZE || default_stksize < MIN_STKSIZE) { cmn_err(CE_WARN, "Illegal stack size. Using %d", (int)DEFAULTSTKSZ); default_stksize = DEFAULTSTKSZ; } else { lwp_default_stksize = default_stksize; } if (lwp_default_stksize == 0) { lwp_default_stksize = default_stksize; } else if (lwp_default_stksize % PAGESIZE != 0 || lwp_default_stksize > MAX_STKSIZE || lwp_default_stksize < MIN_STKSIZE) { cmn_err(CE_WARN, "Illegal stack size. Using %d", default_stksize); lwp_default_stksize = default_stksize; } segkp_lwp = segkp_cache_init(segkp, lwp_cache_sz, lwp_default_stksize, (KPD_NOWAIT | KPD_HASREDZONE | KPD_LOCKED)); segkp_thread = segkp_cache_init(segkp, t_cache_sz, default_stksize, KPD_HASREDZONE | KPD_LOCKED | KPD_NO_ANON); (void) getcid(sys_name, &syscid); curthread->t_cid = syscid; /* current thread is t0 */ /* * Set up the first CPU's idle thread. * It runs whenever the CPU has nothing worthwhile to do. */ tp = thread_create(NULL, 0, idle, NULL, 0, &p0, TS_STOPPED, -1); cpu->cpu_idle_thread = tp; tp->t_preempt = 1; tp->t_disp_queue = cpu->cpu_disp; ASSERT(tp->t_disp_queue != NULL); tp->t_bound_cpu = cpu; tp->t_affinitycnt = 1; /* * Registering a thread in the callback table is usually * done in the initialization code of the thread. In this * case, we do it right after thread creation to avoid * blocking idle thread while registering itself. It also * avoids the possibility of reregistration in case a CPU * restarts its idle thread. */ CALLB_CPR_INIT_SAFE(tp, "idle"); /* * Create the thread_reaper daemon. From this point on, exited * threads will get reaped. */ (void) thread_create(NULL, 0, (void (*)())thread_reaper, NULL, 0, &p0, TS_RUN, minclsyspri); /* * Finish initializing the kernel memory allocator now that * thread_create() is available. */ kmem_thread_init(); if (boothowto & RB_DEBUG) kdi_dvec_thravail(); } /* * Create a thread. * * thread_create() blocks for memory if necessary. It never fails. * * If stk is NULL, the thread is created at the base of the stack * and cannot be swapped. */ kthread_t * thread_create( caddr_t stk, size_t stksize, void (*proc)(), void *arg, size_t len, proc_t *pp, int state, pri_t pri) { kthread_t *t; extern struct classfuncs sys_classfuncs; turnstile_t *ts; /* * Every thread keeps a turnstile around in case it needs to block. * The only reason the turnstile is not simply part of the thread * structure is that we may have to break the association whenever * more than one thread blocks on a given synchronization object. * From a memory-management standpoint, turnstiles are like the * "attached mblks" that hang off dblks in the streams allocator. */ ts = kmem_cache_alloc(turnstile_cache, KM_SLEEP); if (stk == NULL) { /* * alloc both thread and stack in segkp chunk */ if (stksize < default_stksize) stksize = default_stksize; if (stksize == default_stksize) { stk = (caddr_t)segkp_cache_get(segkp_thread); } else { stksize = roundup(stksize, PAGESIZE); stk = (caddr_t)segkp_get(segkp, stksize, (KPD_HASREDZONE | KPD_NO_ANON | KPD_LOCKED)); } ASSERT(stk != NULL); /* * The machine-dependent mutex code may require that * thread pointers (since they may be used for mutex owner * fields) have certain alignment requirements. * PTR24_ALIGN is the size of the alignment quanta. * XXX - assumes stack grows toward low addresses. */ if (stksize <= sizeof (kthread_t) + PTR24_ALIGN) cmn_err(CE_PANIC, "thread_create: proposed stack size" " too small to hold thread."); #ifdef STACK_GROWTH_DOWN stksize -= SA(sizeof (kthread_t) + PTR24_ALIGN - 1); stksize &= -PTR24_ALIGN; /* make thread aligned */ t = (kthread_t *)(stk + stksize); bzero(t, sizeof (kthread_t)); if (audit_active) audit_thread_create(t); t->t_stk = stk + stksize; t->t_stkbase = stk; #else /* stack grows to larger addresses */ stksize -= SA(sizeof (kthread_t)); t = (kthread_t *)(stk); bzero(t, sizeof (kthread_t)); t->t_stk = stk + sizeof (kthread_t); t->t_stkbase = stk + stksize + sizeof (kthread_t); #endif /* STACK_GROWTH_DOWN */ t->t_flag |= T_TALLOCSTK; t->t_swap = stk; } else { t = kmem_cache_alloc(thread_cache, KM_SLEEP); bzero(t, sizeof (kthread_t)); ASSERT(((uintptr_t)t & (PTR24_ALIGN - 1)) == 0); if (audit_active) audit_thread_create(t); /* * Initialize t_stk to the kernel stack pointer to use * upon entry to the kernel */ #ifdef STACK_GROWTH_DOWN t->t_stk = stk + stksize; t->t_stkbase = stk; #else t->t_stk = stk; /* 3b2-like */ t->t_stkbase = stk + stksize; #endif /* STACK_GROWTH_DOWN */ } /* set default stack flag */ if (stksize == lwp_default_stksize) t->t_flag |= T_DFLTSTK; t->t_ts = ts; /* * p_cred could be NULL if it thread_create is called before cred_init * is called in main. */ mutex_enter(&pp->p_crlock); if (pp->p_cred) crhold(t->t_cred = pp->p_cred); mutex_exit(&pp->p_crlock); t->t_start = gethrestime_sec(); t->t_startpc = proc; t->t_procp = pp; t->t_clfuncs = &sys_classfuncs.thread; t->t_cid = syscid; t->t_pri = pri; t->t_stime = lbolt; t->t_schedflag = TS_LOAD | TS_DONT_SWAP; t->t_bind_cpu = PBIND_NONE; t->t_bind_pset = PS_NONE; t->t_plockp = &pp->p_lock; t->t_copyops = NULL; t->t_taskq = NULL; t->t_anttime = 0; t->t_hatdepth = 0; t->t_dtrace_vtime = 1; /* assure vtimestamp is always non-zero */ CPU_STATS_ADDQ(CPU, sys, nthreads, 1); #ifndef NPROBE /* Kernel probe */ tnf_thread_create(t); #endif /* NPROBE */ LOCK_INIT_CLEAR(&t->t_lock); /* * Callers who give us a NULL proc must do their own * stack initialization. e.g. lwp_create() */ if (proc != NULL) { t->t_stk = thread_stk_init(t->t_stk); thread_load(t, proc, arg, len); } /* * Put a hold on project0. If this thread is actually in a * different project, then t_proj will be changed later in * lwp_create(). All kernel-only threads must be in project 0. */ t->t_proj = project_hold(proj0p); lgrp_affinity_init(&t->t_lgrp_affinity); mutex_enter(&pidlock); nthread++; t->t_did = next_t_id++; t->t_prev = curthread->t_prev; t->t_next = curthread; /* * Add the thread to the list of all threads, and initialize * its t_cpu pointer. We need to block preemption since * cpu_offline walks the thread list looking for threads * with t_cpu pointing to the CPU being offlined. We want * to make sure that the list is consistent and that if t_cpu * is set, the thread is on the list. */ kpreempt_disable(); curthread->t_prev->t_next = t; curthread->t_prev = t; /* * Threads should never have a NULL t_cpu pointer so assign it * here. If the thread is being created with state TS_RUN a * better CPU may be chosen when it is placed on the run queue. * * We need to keep kernel preemption disabled when setting all * three fields to keep them in sync. Also, always create in * the default partition since that's where kernel threads go * (if this isn't a kernel thread, t_cpupart will be changed * in lwp_create before setting the thread runnable). */ t->t_cpupart = &cp_default; /* * For now, affiliate this thread with the root lgroup. * Since the kernel does not (presently) allocate its memory * in a locality aware fashion, the root is an appropriate home. * If this thread is later associated with an lwp, it will have * it's lgroup re-assigned at that time. */ lgrp_move_thread(t, &cp_default.cp_lgrploads[LGRP_ROOTID], 1); /* * Inherit the current cpu. If this cpu isn't part of the chosen * lgroup, a new cpu will be chosen by cpu_choose when the thread * is ready to run. */ if (CPU->cpu_part == &cp_default) t->t_cpu = CPU; else t->t_cpu = disp_lowpri_cpu(cp_default.cp_cpulist, t->t_lpl, t->t_pri, NULL); t->t_disp_queue = t->t_cpu->cpu_disp; kpreempt_enable(); /* * Initialize thread state and the dispatcher lock pointer. * Need to hold onto pidlock to block allthreads walkers until * the state is set. */ switch (state) { case TS_RUN: curthread->t_oldspl = splhigh(); /* get dispatcher spl */ THREAD_SET_STATE(t, TS_STOPPED, &transition_lock); CL_SETRUN(t); thread_unlock(t); break; case TS_ONPROC: THREAD_ONPROC(t, t->t_cpu); break; case TS_FREE: /* * Free state will be used for intr threads. * The interrupt routine must set the thread dispatcher * lock pointer (t_lockp) if starting on a CPU * other than the current one. */ THREAD_FREEINTR(t, CPU); break; case TS_STOPPED: THREAD_SET_STATE(t, TS_STOPPED, &stop_lock); break; default: /* TS_SLEEP, TS_ZOMB or TS_TRANS */ cmn_err(CE_PANIC, "thread_create: invalid state %d", state); } mutex_exit(&pidlock); return (t); } /* * Move thread to project0 and take care of project reference counters. */ void thread_rele(kthread_t *t) { kproject_t *kpj; thread_lock(t); ASSERT(t == curthread || t->t_state == TS_FREE || t->t_procp == &p0); kpj = ttoproj(t); t->t_proj = proj0p; thread_unlock(t); if (kpj != proj0p) { project_rele(kpj); (void) project_hold(proj0p); } } void thread_exit(void) { kthread_t *t = curthread; if ((t->t_proc_flag & TP_ZTHREAD) != 0) cmn_err(CE_PANIC, "thread_exit: zthread_exit() not called"); tsd_exit(); /* Clean up this thread's TSD */ kcpc_passivate(); /* clean up performance counter state */ /* * No kernel thread should have called poll() without arranging * calling pollcleanup() here. */ ASSERT(t->t_pollstate == NULL); ASSERT(t->t_schedctl == NULL); if (t->t_door) door_slam(); /* in case thread did an upcall */ #ifndef NPROBE /* Kernel probe */ if (t->t_tnf_tpdp) tnf_thread_exit(); #endif /* NPROBE */ thread_rele(t); t->t_preempt++; /* * remove thread from the all threads list so that * death-row can use the same pointers. */ mutex_enter(&pidlock); t->t_next->t_prev = t->t_prev; t->t_prev->t_next = t->t_next; ASSERT(allthreads != t); /* t0 never exits */ cv_broadcast(&t->t_joincv); /* wake up anyone in thread_join */ mutex_exit(&pidlock); if (t->t_ctx != NULL) exitctx(t); if (t->t_procp->p_pctx != NULL) exitpctx(t->t_procp); t->t_state = TS_ZOMB; /* set zombie thread */ swtch_from_zombie(); /* give up the CPU */ /* NOTREACHED */ } /* * Check to see if the specified thread is active (defined as being on * the thread list). This is certainly a slow way to do this; if there's * ever a reason to speed it up, we could maintain a hash table of active * threads indexed by their t_did. */ static kthread_t * did_to_thread(kt_did_t tid) { kthread_t *t; ASSERT(MUTEX_HELD(&pidlock)); for (t = curthread->t_next; t != curthread; t = t->t_next) { if (t->t_did == tid) break; } if (t->t_did == tid) return (t); else return (NULL); } /* * Wait for specified thread to exit. Returns immediately if the thread * could not be found, meaning that it has either already exited or never * existed. */ void thread_join(kt_did_t tid) { kthread_t *t; ASSERT(tid != curthread->t_did); ASSERT(tid != t0.t_did); mutex_enter(&pidlock); /* * Make sure we check that the thread is on the thread list * before blocking on it; otherwise we could end up blocking on * a cv that's already been freed. In other words, don't cache * the thread pointer across calls to cv_wait. * * The choice of loop invariant means that whenever a thread * is taken off the allthreads list, a cv_broadcast must be * performed on that thread's t_joincv to wake up any waiters. * The broadcast doesn't have to happen right away, but it * shouldn't be postponed indefinitely (e.g., by doing it in * thread_free which may only be executed when the deathrow * queue is processed. */ while (t = did_to_thread(tid)) cv_wait(&t->t_joincv, &pidlock); mutex_exit(&pidlock); } void thread_free_prevent(kthread_t *t) { kmutex_t *lp; lp = &thread_free_lock[THREAD_FREE_HASH(t)].tf_lock; mutex_enter(lp); } void thread_free_allow(kthread_t *t) { kmutex_t *lp; lp = &thread_free_lock[THREAD_FREE_HASH(t)].tf_lock; mutex_exit(lp); } static void thread_free_barrier(kthread_t *t) { kmutex_t *lp; lp = &thread_free_lock[THREAD_FREE_HASH(t)].tf_lock; mutex_enter(lp); mutex_exit(lp); } void thread_free(kthread_t *t) { ASSERT(t != &t0 && t->t_state == TS_FREE); ASSERT(t->t_door == NULL); ASSERT(t->t_schedctl == NULL); ASSERT(t->t_pollstate == NULL); t->t_pri = 0; t->t_pc = 0; t->t_sp = 0; t->t_wchan0 = NULL; t->t_wchan = NULL; if (t->t_cred != NULL) { crfree(t->t_cred); t->t_cred = 0; } if (t->t_pdmsg) { kmem_free(t->t_pdmsg, strlen(t->t_pdmsg) + 1); t->t_pdmsg = NULL; } if (audit_active) audit_thread_free(t); #ifndef NPROBE if (t->t_tnf_tpdp) tnf_thread_free(t); #endif /* NPROBE */ if (t->t_cldata) { CL_EXITCLASS(t->t_cid, (caddr_t *)t->t_cldata); } if (t->t_rprof != NULL) { kmem_free(t->t_rprof, sizeof (*t->t_rprof)); t->t_rprof = NULL; } t->t_lockp = NULL; /* nothing should try to lock this thread now */ if (t->t_lwp) lwp_freeregs(t->t_lwp, 0); if (t->t_ctx) freectx(t, 0); t->t_stk = NULL; if (t->t_lwp) lwp_stk_fini(t->t_lwp); lock_clear(&t->t_lock); if (t->t_ts->ts_waiters > 0) panic("thread_free: turnstile still active"); kmem_cache_free(turnstile_cache, t->t_ts); free_afd(&t->t_activefd); /* * Barrier for the tick accounting code. The tick accounting code * holds this lock to keep the thread from going away while it's * looking at it. */ thread_free_barrier(t); ASSERT(ttoproj(t) == proj0p); project_rele(ttoproj(t)); lgrp_affinity_free(&t->t_lgrp_affinity); /* * Free thread struct and its stack. */ if (t->t_flag & T_TALLOCSTK) { /* thread struct is embedded in stack */ segkp_release(segkp, t->t_swap); mutex_enter(&pidlock); nthread--; mutex_exit(&pidlock); } else { if (t->t_swap) { segkp_release(segkp, t->t_swap); t->t_swap = NULL; } if (t->t_lwp) { kmem_cache_free(lwp_cache, t->t_lwp); t->t_lwp = NULL; } mutex_enter(&pidlock); nthread--; mutex_exit(&pidlock); kmem_cache_free(thread_cache, t); } } /* * Removes threads associated with the given zone from a deathrow queue. * tp is a pointer to the head of the deathrow queue, and countp is a * pointer to the current deathrow count. Returns a linked list of * threads removed from the list. */ static kthread_t * thread_zone_cleanup(kthread_t **tp, int *countp, zoneid_t zoneid) { kthread_t *tmp, *list = NULL; cred_t *cr; ASSERT(MUTEX_HELD(&reaplock)); while (*tp != NULL) { if ((cr = (*tp)->t_cred) != NULL && crgetzoneid(cr) == zoneid) { tmp = *tp; *tp = tmp->t_forw; tmp->t_forw = list; list = tmp; (*countp)--; } else { tp = &(*tp)->t_forw; } } return (list); } static void thread_reap_list(kthread_t *t) { kthread_t *next; while (t != NULL) { next = t->t_forw; thread_free(t); t = next; } } /* ARGSUSED */ static void thread_zone_destroy(zoneid_t zoneid, void *unused) { kthread_t *t, *l; mutex_enter(&reaplock); /* * Pull threads and lwps associated with zone off deathrow lists. */ t = thread_zone_cleanup(&thread_deathrow, &thread_reapcnt, zoneid); l = thread_zone_cleanup(&lwp_deathrow, &lwp_reapcnt, zoneid); mutex_exit(&reaplock); /* * Reap threads */ thread_reap_list(t); /* * Reap lwps */ thread_reap_list(l); } /* * cleanup zombie threads that are on deathrow. */ void thread_reaper() { kthread_t *t, *l; callb_cpr_t cprinfo; /* * Register callback to clean up threads when zone is destroyed. */ zone_key_create(&zone_thread_key, NULL, NULL, thread_zone_destroy); CALLB_CPR_INIT(&cprinfo, &reaplock, callb_generic_cpr, "t_reaper"); for (;;) { mutex_enter(&reaplock); while (thread_deathrow == NULL && lwp_deathrow == NULL) { CALLB_CPR_SAFE_BEGIN(&cprinfo); cv_wait(&reaper_cv, &reaplock); CALLB_CPR_SAFE_END(&cprinfo, &reaplock); } t = thread_deathrow; l = lwp_deathrow; thread_deathrow = NULL; lwp_deathrow = NULL; thread_reapcnt = 0; lwp_reapcnt = 0; mutex_exit(&reaplock); /* * Reap threads */ thread_reap_list(t); /* * Reap lwps */ thread_reap_list(l); } } /* * This is called by resume() to put a zombie thread onto deathrow. * The thread's state is changed to TS_FREE to indicate that is reapable. * This is called from the idle thread so it must not block (just spin). */ void reapq_add(kthread_t *t) { mutex_enter(&reaplock); /* * lwp_deathrow contains only threads with lwp linkage * that are of the default stacksize. Anything else goes * on thread_deathrow. */ if (ttolwp(t) && (t->t_flag & T_DFLTSTK)) { t->t_forw = lwp_deathrow; lwp_deathrow = t; lwp_reapcnt++; } else { t->t_forw = thread_deathrow; thread_deathrow = t; thread_reapcnt++; } if (lwp_reapcnt + thread_reapcnt > reaplimit) cv_signal(&reaper_cv); /* wake the reaper */ t->t_state = TS_FREE; lock_clear(&t->t_lock); /* * Before we return, we need to grab and drop the thread lock for * the dead thread. At this point, the current thread is the idle * thread, and the dead thread's CPU lock points to the current * CPU -- and we must grab and drop the lock to synchronize with * a racing thread walking a blocking chain that the zombie thread * was recently in. By this point, that blocking chain is (by * definition) stale: the dead thread is not holding any locks, and * is therefore not in any blocking chains -- but if we do not regrab * our lock before freeing the dead thread's data structures, the * thread walking the (stale) blocking chain will die on memory * corruption when it attempts to drop the dead thread's lock. We * only need do this once because there is no way for the dead thread * to ever again be on a blocking chain: once we have grabbed and * dropped the thread lock, we are guaranteed that anyone that could * have seen this thread in a blocking chain can no longer see it. */ thread_lock(t); thread_unlock(t); mutex_exit(&reaplock); } /* * Install thread context ops for the current thread. */ void installctx( kthread_t *t, void *arg, void (*save)(void *), void (*restore)(void *), void (*fork)(void *, void *), void (*lwp_create)(void *, void *), void (*exit)(void *), void (*free)(void *, int)) { struct ctxop *ctx; ctx = kmem_alloc(sizeof (struct ctxop), KM_SLEEP); ctx->save_op = save; ctx->restore_op = restore; ctx->fork_op = fork; ctx->lwp_create_op = lwp_create; ctx->exit_op = exit; ctx->free_op = free; ctx->arg = arg; ctx->next = t->t_ctx; t->t_ctx = ctx; } /* * Remove the thread context ops from a thread. */ int removectx( kthread_t *t, void *arg, void (*save)(void *), void (*restore)(void *), void (*fork)(void *, void *), void (*lwp_create)(void *, void *), void (*exit)(void *), void (*free)(void *, int)) { struct ctxop *ctx, *prev_ctx; /* * The incoming kthread_t (which is the thread for which the * context ops will be removed) should be one of the following: * * a) the current thread, * * b) a thread of a process that's being forked (SIDL), * * c) a thread that belongs to the same process as the current * thread and for which the current thread is the agent thread, * * d) a thread that is TS_STOPPED which is indicative of it * being (if curthread is not an agent) a thread being created * as part of an lwp creation. */ ASSERT(t == curthread || ttoproc(t)->p_stat == SIDL || ttoproc(t)->p_agenttp == curthread || t->t_state == TS_STOPPED); /* * Serialize modifications to t->t_ctx to prevent the agent thread * and the target thread from racing with each other during lwp exit. */ mutex_enter(&t->t_ctx_lock); prev_ctx = NULL; for (ctx = t->t_ctx; ctx != NULL; ctx = ctx->next) { if (ctx->save_op == save && ctx->restore_op == restore && ctx->fork_op == fork && ctx->lwp_create_op == lwp_create && ctx->exit_op == exit && ctx->free_op == free && ctx->arg == arg) { if (prev_ctx) prev_ctx->next = ctx->next; else t->t_ctx = ctx->next; mutex_exit(&t->t_ctx_lock); if (ctx->free_op != NULL) (ctx->free_op)(ctx->arg, 0); kmem_free(ctx, sizeof (struct ctxop)); return (1); } prev_ctx = ctx; } mutex_exit(&t->t_ctx_lock); return (0); } void savectx(kthread_t *t) { struct ctxop *ctx; ASSERT(t == curthread); for (ctx = t->t_ctx; ctx != 0; ctx = ctx->next) if (ctx->save_op != NULL) (ctx->save_op)(ctx->arg); } void restorectx(kthread_t *t) { struct ctxop *ctx; ASSERT(t == curthread); for (ctx = t->t_ctx; ctx != 0; ctx = ctx->next) if (ctx->restore_op != NULL) (ctx->restore_op)(ctx->arg); } void forkctx(kthread_t *t, kthread_t *ct) { struct ctxop *ctx; for (ctx = t->t_ctx; ctx != NULL; ctx = ctx->next) if (ctx->fork_op != NULL) (ctx->fork_op)(t, ct); } /* * Note that this operator is only invoked via the _lwp_create * system call. The system may have other reasons to create lwps * e.g. the agent lwp or the doors unreferenced lwp. */ void lwp_createctx(kthread_t *t, kthread_t *ct) { struct ctxop *ctx; for (ctx = t->t_ctx; ctx != NULL; ctx = ctx->next) if (ctx->lwp_create_op != NULL) (ctx->lwp_create_op)(t, ct); } /* * exitctx is called from thread_exit() and lwp_exit() to perform any actions * needed when the thread/LWP leaves the processor for the last time. This * routine is not intended to deal with freeing memory; freectx() is used for * that purpose during thread_free(). This routine is provided to allow for * clean-up that can't wait until thread_free(). */ void exitctx(kthread_t *t) { struct ctxop *ctx; for (ctx = t->t_ctx; ctx != NULL; ctx = ctx->next) if (ctx->exit_op != NULL) (ctx->exit_op)(t); } /* * freectx is called from thread_free() and exec() to get * rid of old thread context ops. */ void freectx(kthread_t *t, int isexec) { struct ctxop *ctx; while ((ctx = t->t_ctx) != NULL) { t->t_ctx = ctx->next; if (ctx->free_op != NULL) (ctx->free_op)(ctx->arg, isexec); kmem_free(ctx, sizeof (struct ctxop)); } } /* * Set the thread running; arrange for it to be swapped in if necessary. */ void setrun_locked(kthread_t *t) { ASSERT(THREAD_LOCK_HELD(t)); if (t->t_state == TS_SLEEP) { /* * Take off sleep queue. */ SOBJ_UNSLEEP(t->t_sobj_ops, t); } else if (t->t_state & (TS_RUN | TS_ONPROC)) { /* * Already on dispatcher queue. */ return; } else if (t->t_state == TS_WAIT) { waitq_setrun(t); } else if (t->t_state == TS_STOPPED) { /* * All of the sending of SIGCONT (TC_XSTART) and /proc * (TC_PSTART) and lwp_continue() (TC_CSTART) must have * requested that the thread be run. * Just calling setrun() is not sufficient to set a stopped * thread running. TP_TXSTART is always set if the thread * is not stopped by a jobcontrol stop signal. * TP_TPSTART is always set if /proc is not controlling it. * TP_TCSTART is always set if lwp_suspend() didn't stop it. * The thread won't be stopped unless one of these * three mechanisms did it. * * These flags must be set before calling setrun_locked(t). * They can't be passed as arguments because the streams * code calls setrun() indirectly and the mechanism for * doing so admits only one argument. Note that the * thread must be locked in order to change t_schedflags. */ if ((t->t_schedflag & TS_ALLSTART) != TS_ALLSTART) return; /* * Process is no longer stopped (a thread is running). */ t->t_whystop = 0; t->t_whatstop = 0; /* * Strictly speaking, we do not have to clear these * flags here; they are cleared on entry to stop(). * However, they are confusing when doing kernel * debugging or when they are revealed by ps(1). */ t->t_schedflag &= ~TS_ALLSTART; THREAD_TRANSITION(t); /* drop stopped-thread lock */ ASSERT(t->t_lockp == &transition_lock); ASSERT(t->t_wchan0 == NULL && t->t_wchan == NULL); /* * Let the class put the process on the dispatcher queue. */ CL_SETRUN(t); } } void setrun(kthread_t *t) { thread_lock(t); setrun_locked(t); thread_unlock(t); } /* * Unpin an interrupted thread. * When an interrupt occurs, the interrupt is handled on the stack * of an interrupt thread, taken from a pool linked to the CPU structure. * * When swtch() is switching away from an interrupt thread because it * blocked or was preempted, this routine is called to complete the * saving of the interrupted thread state, and returns the interrupted * thread pointer so it may be resumed. * * Called by swtch() only at high spl. */ kthread_t * thread_unpin() { kthread_t *t = curthread; /* current thread */ kthread_t *itp; /* interrupted thread */ int i; /* interrupt level */ extern int intr_passivate(); ASSERT(t->t_intr != NULL); itp = t->t_intr; /* interrupted thread */ t->t_intr = NULL; /* clear interrupt ptr */ /* * Get state from interrupt thread for the one * it interrupted. */ i = intr_passivate(t, itp); TRACE_5(TR_FAC_INTR, TR_INTR_PASSIVATE, "intr_passivate:level %d curthread %p (%T) ithread %p (%T)", i, t, t, itp, itp); /* * Dissociate the current thread from the interrupted thread's LWP. */ t->t_lwp = NULL; /* * Interrupt handlers above the level that spinlocks block must * not block. */ #if DEBUG if (i < 0 || i > LOCK_LEVEL) cmn_err(CE_PANIC, "thread_unpin: ipl out of range %x", i); #endif /* * Compute the CPU's base interrupt level based on the active * interrupts. */ ASSERT(CPU->cpu_intr_actv & (1 << i)); set_base_spl(); return (itp); } /* * Create and initialize an interrupt thread. * Returns non-zero on error. * Called at spl7() or better. */ void thread_create_intr(struct cpu *cp) { kthread_t *tp; tp = thread_create(NULL, 0, (void (*)())thread_create_intr, NULL, 0, &p0, TS_ONPROC, 0); /* * Set the thread in the TS_FREE state. The state will change * to TS_ONPROC only while the interrupt is active. Think of these * as being on a private free list for the CPU. Being TS_FREE keeps * inactive interrupt threads out of debugger thread lists. * * We cannot call thread_create with TS_FREE because of the current * checks there for ONPROC. Fix this when thread_create takes flags. */ THREAD_FREEINTR(tp, cp); /* * Nobody should ever reference the credentials of an interrupt * thread so make it NULL to catch any such references. */ tp->t_cred = NULL; tp->t_flag |= T_INTR_THREAD; tp->t_cpu = cp; tp->t_bound_cpu = cp; tp->t_disp_queue = cp->cpu_disp; tp->t_affinitycnt = 1; tp->t_preempt = 1; /* * Don't make a user-requested binding on this thread so that * the processor can be offlined. */ tp->t_bind_cpu = PBIND_NONE; /* no USER-requested binding */ tp->t_bind_pset = PS_NONE; #if defined(__i386) || defined(__amd64) tp->t_stk -= STACK_ALIGN; *(tp->t_stk) = 0; /* terminate intr thread stack */ #endif /* * Link onto CPU's interrupt pool. */ tp->t_link = cp->cpu_intr_thread; cp->cpu_intr_thread = tp; } /* * TSD -- THREAD SPECIFIC DATA */ static kmutex_t tsd_mutex; /* linked list spin lock */ static uint_t tsd_nkeys; /* size of destructor array */ /* per-key destructor funcs */ static void (**tsd_destructor)(void *); /* list of tsd_thread's */ static struct tsd_thread *tsd_list; /* * Default destructor * Needed because NULL destructor means that the key is unused */ /* ARGSUSED */ void tsd_defaultdestructor(void *value) {} /* * Create a key (index into per thread array) * Locks out tsd_create, tsd_destroy, and tsd_exit * May allocate memory with lock held */ void tsd_create(uint_t *keyp, void (*destructor)(void *)) { int i; uint_t nkeys; /* * if key is allocated, do nothing */ mutex_enter(&tsd_mutex); if (*keyp) { mutex_exit(&tsd_mutex); return; } /* * find an unused key */ if (destructor == NULL) destructor = tsd_defaultdestructor; for (i = 0; i < tsd_nkeys; ++i) if (tsd_destructor[i] == NULL) break; /* * if no unused keys, increase the size of the destructor array */ if (i == tsd_nkeys) { if ((nkeys = (tsd_nkeys << 1)) == 0) nkeys = 1; tsd_destructor = (void (**)(void *))tsd_realloc((void *)tsd_destructor, (size_t)(tsd_nkeys * sizeof (void (*)(void *))), (size_t)(nkeys * sizeof (void (*)(void *)))); tsd_nkeys = nkeys; } /* * allocate the next available unused key */ tsd_destructor[i] = destructor; *keyp = i + 1; mutex_exit(&tsd_mutex); } /* * Destroy a key -- this is for unloadable modules * * Assumes that the caller is preventing tsd_set and tsd_get * Locks out tsd_create, tsd_destroy, and tsd_exit * May free memory with lock held */ void tsd_destroy(uint_t *keyp) { uint_t key; struct tsd_thread *tsd; /* * protect the key namespace and our destructor lists */ mutex_enter(&tsd_mutex); key = *keyp; *keyp = 0; ASSERT(key <= tsd_nkeys); /* * if the key is valid */ if (key != 0) { uint_t k = key - 1; /* * for every thread with TSD, call key's destructor */ for (tsd = tsd_list; tsd; tsd = tsd->ts_next) { /* * no TSD for key in this thread */ if (key > tsd->ts_nkeys) continue; /* * call destructor for key */ if (tsd->ts_value[k] && tsd_destructor[k]) (*tsd_destructor[k])(tsd->ts_value[k]); /* * reset value for key */ tsd->ts_value[k] = NULL; } /* * actually free the key (NULL destructor == unused) */ tsd_destructor[k] = NULL; } mutex_exit(&tsd_mutex); } /* * Quickly return the per thread value that was stored with the specified key * Assumes the caller is protecting key from tsd_create and tsd_destroy */ void * tsd_get(uint_t key) { return (tsd_agent_get(curthread, key)); } /* * Set a per thread value indexed with the specified key */ int tsd_set(uint_t key, void *value) { return (tsd_agent_set(curthread, key, value)); } /* * Like tsd_get(), except that the agent lwp can get the tsd of * another thread in the same process (the agent thread only runs when the * process is completely stopped by /proc), or syslwp is creating a new lwp. */ void * tsd_agent_get(kthread_t *t, uint_t key) { struct tsd_thread *tsd = t->t_tsd; ASSERT(t == curthread || ttoproc(t)->p_agenttp == curthread || t->t_state == TS_STOPPED); if (key && tsd != NULL && key <= tsd->ts_nkeys) return (tsd->ts_value[key - 1]); return (NULL); } /* * Like tsd_set(), except that the agent lwp can set the tsd of * another thread in the same process, or syslwp can set the tsd * of a thread it's in the middle of creating. * * Assumes the caller is protecting key from tsd_create and tsd_destroy * May lock out tsd_destroy (and tsd_create), may allocate memory with * lock held */ int tsd_agent_set(kthread_t *t, uint_t key, void *value) { struct tsd_thread *tsd = t->t_tsd; ASSERT(t == curthread || ttoproc(t)->p_agenttp == curthread || t->t_state == TS_STOPPED); if (key == 0) return (EINVAL); if (tsd == NULL) tsd = t->t_tsd = kmem_zalloc(sizeof (*tsd), KM_SLEEP); if (key <= tsd->ts_nkeys) { tsd->ts_value[key - 1] = value; return (0); } ASSERT(key <= tsd_nkeys); /* * lock out tsd_destroy() */ mutex_enter(&tsd_mutex); if (tsd->ts_nkeys == 0) { /* * Link onto list of threads with TSD */ if ((tsd->ts_next = tsd_list) != NULL) tsd_list->ts_prev = tsd; tsd_list = tsd; } /* * Allocate thread local storage and set the value for key */ tsd->ts_value = tsd_realloc(tsd->ts_value, tsd->ts_nkeys * sizeof (void *), key * sizeof (void *)); tsd->ts_nkeys = key; tsd->ts_value[key - 1] = value; mutex_exit(&tsd_mutex); return (0); } /* * Return the per thread value that was stored with the specified key * If necessary, create the key and the value * Assumes the caller is protecting *keyp from tsd_destroy */ void * tsd_getcreate(uint_t *keyp, void (*destroy)(void *), void *(*allocate)(void)) { void *value; uint_t key = *keyp; struct tsd_thread *tsd = curthread->t_tsd; if (tsd == NULL) tsd = curthread->t_tsd = kmem_zalloc(sizeof (*tsd), KM_SLEEP); if (key && key <= tsd->ts_nkeys && (value = tsd->ts_value[key - 1])) return (value); if (key == 0) tsd_create(keyp, destroy); (void) tsd_set(*keyp, value = (*allocate)()); return (value); } /* * Called from thread_exit() to run the destructor function for each tsd * Locks out tsd_create and tsd_destroy * Assumes that the destructor *DOES NOT* use tsd */ void tsd_exit(void) { int i; struct tsd_thread *tsd = curthread->t_tsd; if (tsd == NULL) return; if (tsd->ts_nkeys == 0) { kmem_free(tsd, sizeof (*tsd)); curthread->t_tsd = NULL; return; } /* * lock out tsd_create and tsd_destroy, call * the destructor, and mark the value as destroyed. */ mutex_enter(&tsd_mutex); for (i = 0; i < tsd->ts_nkeys; i++) { if (tsd->ts_value[i] && tsd_destructor[i]) (*tsd_destructor[i])(tsd->ts_value[i]); tsd->ts_value[i] = NULL; } /* * remove from linked list of threads with TSD */ if (tsd->ts_next) tsd->ts_next->ts_prev = tsd->ts_prev; if (tsd->ts_prev) tsd->ts_prev->ts_next = tsd->ts_next; if (tsd_list == tsd) tsd_list = tsd->ts_next; mutex_exit(&tsd_mutex); /* * free up the TSD */ kmem_free(tsd->ts_value, tsd->ts_nkeys * sizeof (void *)); kmem_free(tsd, sizeof (struct tsd_thread)); curthread->t_tsd = NULL; } /* * realloc */ static void * tsd_realloc(void *old, size_t osize, size_t nsize) { void *new; new = kmem_zalloc(nsize, KM_SLEEP); if (old) { bcopy(old, new, osize); kmem_free(old, osize); } return (new); } /* * Check to see if an interrupt thread might be active at a given ipl. * If so return true. * We must be conservative--it is ok to give a false yes, but a false no * will cause disaster. (But if the situation changes after we check it is * ok--the caller is trying to ensure that an interrupt routine has been * exited). * This is used when trying to remove an interrupt handler from an autovector * list in avintr.c. */ int intr_active(struct cpu *cp, int level) { if (level <= LOCK_LEVEL) return (cp->cpu_thread != cp->cpu_dispthread); else return (CPU_ON_INTR(cp)); } /* * Return non-zero if an interrupt is being serviced. */ int servicing_interrupt() { int onintr = 0; /* Are we an interrupt thread */ if (curthread->t_flag & T_INTR_THREAD) return (1); /* Are we servicing a high level interrupt? */ if (CPU_ON_INTR(CPU)) { kpreempt_disable(); onintr = CPU_ON_INTR(CPU); kpreempt_enable(); } return (onintr); } /* * Change the dispatch priority of a thread in the system. * Used when raising or lowering a thread's priority. * (E.g., priority inheritance) * * Since threads are queued according to their priority, we * we must check the thread's state to determine whether it * is on a queue somewhere. If it is, we've got to: * * o Dequeue the thread. * o Change its effective priority. * o Enqueue the thread. * * Assumptions: The thread whose priority we wish to change * must be locked before we call thread_change_(e)pri(). * The thread_change(e)pri() function doesn't drop the thread * lock--that must be done by its caller. */ void thread_change_epri(kthread_t *t, pri_t disp_pri) { uint_t state; ASSERT(THREAD_LOCK_HELD(t)); /* * If the inherited priority hasn't actually changed, * just return. */ if (t->t_epri == disp_pri) return; state = t->t_state; /* * If it's not on a queue, change the priority with * impunity. */ if ((state & (TS_SLEEP | TS_RUN | TS_WAIT)) == 0) { t->t_epri = disp_pri; if (state == TS_ONPROC) { cpu_t *cp = t->t_disp_queue->disp_cpu; if (t == cp->cpu_dispthread) cp->cpu_dispatch_pri = DISP_PRIO(t); } return; } /* * It's either on a sleep queue or a run queue. */ if (state == TS_SLEEP) { /* * Take the thread out of its sleep queue. * Change the inherited priority. * Re-enqueue the thread. * Each synchronization object exports a function * to do this in an appropriate manner. */ SOBJ_CHANGE_EPRI(t->t_sobj_ops, t, disp_pri); } else if (state == TS_WAIT) { /* * Re-enqueue a thread on the wait queue if its * effective priority needs to change. */ if (disp_pri != t->t_epri) waitq_change_pri(t, disp_pri); } else { /* * The thread is on a run queue. * Note: setbackdq() may not put the thread * back on the same run queue where it originally * resided. */ (void) dispdeq(t); t->t_epri = disp_pri; setbackdq(t); } } /* end of thread_change_epri */ /* * Function: Change the t_pri field of a thread. * Side Effects: Adjust the thread ordering on a run queue * or sleep queue, if necessary. * Returns: 1 if the thread was on a run queue, else 0. */ int thread_change_pri(kthread_t *t, pri_t disp_pri, int front) { uint_t state; int on_rq = 0; ASSERT(THREAD_LOCK_HELD(t)); state = t->t_state; THREAD_WILLCHANGE_PRI(t, disp_pri); /* * If it's not on a queue, change the priority with * impunity. */ if ((state & (TS_SLEEP | TS_RUN | TS_WAIT)) == 0) { t->t_pri = disp_pri; if (state == TS_ONPROC) { cpu_t *cp = t->t_disp_queue->disp_cpu; if (t == cp->cpu_dispthread) cp->cpu_dispatch_pri = DISP_PRIO(t); } return (0); } /* * It's either on a sleep queue or a run queue. */ if (state == TS_SLEEP) { /* * If the priority has changed, take the thread out of * its sleep queue and change the priority. * Re-enqueue the thread. * Each synchronization object exports a function * to do this in an appropriate manner. */ if (disp_pri != t->t_pri) SOBJ_CHANGE_PRI(t->t_sobj_ops, t, disp_pri); } else if (state == TS_WAIT) { /* * Re-enqueue a thread on the wait queue if its * priority needs to change. */ if (disp_pri != t->t_pri) waitq_change_pri(t, disp_pri); } else { /* * The thread is on a run queue. * Note: setbackdq() may not put the thread * back on the same run queue where it originally * resided. * * We still requeue the thread even if the priority * is unchanged to preserve round-robin (and other) * effects between threads of the same priority. */ on_rq = dispdeq(t); ASSERT(on_rq); t->t_pri = disp_pri; if (front) { setfrontdq(t); } else { setbackdq(t); } } return (on_rq); }