d7f687fc9b
and assignment. - Add a reference to a struct cpuset in each thread that is inherited from the thread that created it. - Release the reference when the thread is destroyed. - Add prototypes for syscalls and macros for manipulating cpusets in sys/cpuset.h - Add syscalls to create, get, and set new numbered cpusets: cpuset(), cpuset_{get,set}id() - Add syscalls for getting and setting affinity masks for cpusets or individual threads: cpuid_{get,set}affinity() - Add types for the 'level' and 'which' parameters for the cpuset. This will permit expansion of the api to cover cpu masks for other objects identifiable with an id_t integer. For example, IRQs and Jails may be coming soon. - The root set 0 contains all valid cpus. All thread initially belong to cpuset 1. This permits migrating all threads off of certain cpus to reserve them for special applications. Sponsored by: Nokia Discussed with: arch, rwatson, brooks, davidxu, deischen Reviewed by: antoine
994 lines
25 KiB
C
994 lines
25 KiB
C
/*-
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* Copyright (C) 2001 Julian Elischer <julian@freebsd.org>.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice(s), this list of conditions and the following disclaimer as
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* the first lines of this file unmodified other than the possible
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* addition of one or more copyright notices.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice(s), this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY
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* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE LIABLE FOR ANY
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* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
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* DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/kernel.h>
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#include <sys/lock.h>
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#include <sys/mutex.h>
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#include <sys/proc.h>
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#include <sys/resourcevar.h>
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#include <sys/smp.h>
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#include <sys/sysctl.h>
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#include <sys/sched.h>
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#include <sys/sleepqueue.h>
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#include <sys/selinfo.h>
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#include <sys/turnstile.h>
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#include <sys/ktr.h>
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#include <sys/umtx.h>
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#include <sys/cpuset.h>
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#include <security/audit/audit.h>
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#include <vm/vm.h>
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#include <vm/vm_extern.h>
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#include <vm/uma.h>
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#include <sys/eventhandler.h>
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/*
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* thread related storage.
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*/
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static uma_zone_t thread_zone;
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SYSCTL_NODE(_kern, OID_AUTO, threads, CTLFLAG_RW, 0, "thread allocation");
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int max_threads_per_proc = 1500;
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SYSCTL_INT(_kern_threads, OID_AUTO, max_threads_per_proc, CTLFLAG_RW,
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&max_threads_per_proc, 0, "Limit on threads per proc");
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int max_threads_hits;
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SYSCTL_INT(_kern_threads, OID_AUTO, max_threads_hits, CTLFLAG_RD,
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&max_threads_hits, 0, "");
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#ifdef KSE
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int virtual_cpu;
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#endif
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TAILQ_HEAD(, thread) zombie_threads = TAILQ_HEAD_INITIALIZER(zombie_threads);
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static struct mtx zombie_lock;
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MTX_SYSINIT(zombie_lock, &zombie_lock, "zombie lock", MTX_SPIN);
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static void thread_zombie(struct thread *);
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#ifdef KSE
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static int
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sysctl_kse_virtual_cpu(SYSCTL_HANDLER_ARGS)
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{
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int error, new_val;
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int def_val;
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def_val = mp_ncpus;
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if (virtual_cpu == 0)
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new_val = def_val;
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else
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new_val = virtual_cpu;
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error = sysctl_handle_int(oidp, &new_val, 0, req);
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if (error != 0 || req->newptr == NULL)
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return (error);
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if (new_val < 0)
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return (EINVAL);
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virtual_cpu = new_val;
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return (0);
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}
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/* DEBUG ONLY */
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SYSCTL_PROC(_kern_threads, OID_AUTO, virtual_cpu, CTLTYPE_INT|CTLFLAG_RW,
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0, sizeof(virtual_cpu), sysctl_kse_virtual_cpu, "I",
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"debug virtual cpus");
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#endif
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struct mtx tid_lock;
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static struct unrhdr *tid_unrhdr;
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/*
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* Prepare a thread for use.
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*/
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static int
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thread_ctor(void *mem, int size, void *arg, int flags)
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{
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struct thread *td;
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td = (struct thread *)mem;
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td->td_state = TDS_INACTIVE;
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td->td_oncpu = NOCPU;
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td->td_tid = alloc_unr(tid_unrhdr);
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td->td_syscalls = 0;
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/*
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* Note that td_critnest begins life as 1 because the thread is not
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* running and is thereby implicitly waiting to be on the receiving
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* end of a context switch.
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*/
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td->td_critnest = 1;
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EVENTHANDLER_INVOKE(thread_ctor, td);
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#ifdef AUDIT
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audit_thread_alloc(td);
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#endif
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umtx_thread_alloc(td);
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return (0);
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}
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/*
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* Reclaim a thread after use.
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*/
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static void
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thread_dtor(void *mem, int size, void *arg)
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{
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struct thread *td;
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td = (struct thread *)mem;
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#ifdef INVARIANTS
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/* Verify that this thread is in a safe state to free. */
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switch (td->td_state) {
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case TDS_INHIBITED:
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case TDS_RUNNING:
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case TDS_CAN_RUN:
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case TDS_RUNQ:
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/*
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* We must never unlink a thread that is in one of
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* these states, because it is currently active.
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*/
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panic("bad state for thread unlinking");
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/* NOTREACHED */
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case TDS_INACTIVE:
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break;
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default:
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panic("bad thread state");
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/* NOTREACHED */
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}
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#endif
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#ifdef AUDIT
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audit_thread_free(td);
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#endif
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EVENTHANDLER_INVOKE(thread_dtor, td);
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free_unr(tid_unrhdr, td->td_tid);
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sched_newthread(td);
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}
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/*
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* Initialize type-stable parts of a thread (when newly created).
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*/
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static int
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thread_init(void *mem, int size, int flags)
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{
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struct thread *td;
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td = (struct thread *)mem;
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td->td_sleepqueue = sleepq_alloc();
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td->td_turnstile = turnstile_alloc();
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EVENTHANDLER_INVOKE(thread_init, td);
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td->td_sched = (struct td_sched *)&td[1];
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sched_newthread(td);
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umtx_thread_init(td);
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td->td_kstack = 0;
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return (0);
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}
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/*
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* Tear down type-stable parts of a thread (just before being discarded).
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*/
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static void
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thread_fini(void *mem, int size)
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{
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struct thread *td;
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td = (struct thread *)mem;
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EVENTHANDLER_INVOKE(thread_fini, td);
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turnstile_free(td->td_turnstile);
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sleepq_free(td->td_sleepqueue);
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umtx_thread_fini(td);
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seltdfini(td);
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}
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/*
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* For a newly created process,
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* link up all the structures and its initial threads etc.
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* called from:
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* {arch}/{arch}/machdep.c ia64_init(), init386() etc.
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* proc_dtor() (should go away)
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* proc_init()
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*/
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void
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proc_linkup0(struct proc *p, struct thread *td)
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{
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TAILQ_INIT(&p->p_threads); /* all threads in proc */
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proc_linkup(p, td);
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}
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void
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proc_linkup(struct proc *p, struct thread *td)
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{
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#ifdef KSE
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TAILQ_INIT(&p->p_upcalls); /* upcall list */
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#endif
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sigqueue_init(&p->p_sigqueue, p);
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p->p_ksi = ksiginfo_alloc(1);
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if (p->p_ksi != NULL) {
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/* XXX p_ksi may be null if ksiginfo zone is not ready */
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p->p_ksi->ksi_flags = KSI_EXT | KSI_INS;
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}
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LIST_INIT(&p->p_mqnotifier);
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p->p_numthreads = 0;
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thread_link(td, p);
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}
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/*
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* Initialize global thread allocation resources.
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*/
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void
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threadinit(void)
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{
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mtx_init(&tid_lock, "TID lock", NULL, MTX_DEF);
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/* leave one number for thread0 */
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tid_unrhdr = new_unrhdr(PID_MAX + 2, INT_MAX, &tid_lock);
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thread_zone = uma_zcreate("THREAD", sched_sizeof_thread(),
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thread_ctor, thread_dtor, thread_init, thread_fini,
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16 - 1, 0);
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#ifdef KSE
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kseinit(); /* set up kse specific stuff e.g. upcall zone*/
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#endif
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}
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/*
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* Place an unused thread on the zombie list.
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* Use the slpq as that must be unused by now.
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*/
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void
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thread_zombie(struct thread *td)
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{
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mtx_lock_spin(&zombie_lock);
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TAILQ_INSERT_HEAD(&zombie_threads, td, td_slpq);
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mtx_unlock_spin(&zombie_lock);
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}
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/*
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* Release a thread that has exited after cpu_throw().
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*/
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void
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thread_stash(struct thread *td)
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{
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atomic_subtract_rel_int(&td->td_proc->p_exitthreads, 1);
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thread_zombie(td);
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}
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/*
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* Reap zombie kse resource.
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*/
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void
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thread_reap(void)
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{
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struct thread *td_first, *td_next;
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/*
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* Don't even bother to lock if none at this instant,
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* we really don't care about the next instant..
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*/
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if (!TAILQ_EMPTY(&zombie_threads)) {
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mtx_lock_spin(&zombie_lock);
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td_first = TAILQ_FIRST(&zombie_threads);
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if (td_first)
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TAILQ_INIT(&zombie_threads);
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mtx_unlock_spin(&zombie_lock);
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while (td_first) {
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td_next = TAILQ_NEXT(td_first, td_slpq);
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if (td_first->td_ucred)
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crfree(td_first->td_ucred);
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thread_free(td_first);
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td_first = td_next;
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}
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}
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#ifdef KSE
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upcall_reap();
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#endif
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}
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/*
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* Allocate a thread.
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*/
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struct thread *
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thread_alloc(void)
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{
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struct thread *td;
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thread_reap(); /* check if any zombies to get */
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td = (struct thread *)uma_zalloc(thread_zone, M_WAITOK);
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KASSERT(td->td_kstack == 0, ("thread_alloc got thread with kstack"));
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if (!vm_thread_new(td, 0)) {
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uma_zfree(thread_zone, td);
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return (NULL);
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}
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cpu_thread_alloc(td);
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return (td);
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}
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/*
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* Deallocate a thread.
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*/
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void
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thread_free(struct thread *td)
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{
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cpuset_rel(td->td_cpuset);
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td->td_cpuset = NULL;
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cpu_thread_free(td);
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if (td->td_altkstack != 0)
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vm_thread_dispose_altkstack(td);
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if (td->td_kstack != 0)
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vm_thread_dispose(td);
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uma_zfree(thread_zone, td);
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}
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/*
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* Discard the current thread and exit from its context.
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* Always called with scheduler locked.
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*
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* Because we can't free a thread while we're operating under its context,
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* push the current thread into our CPU's deadthread holder. This means
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* we needn't worry about someone else grabbing our context before we
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* do a cpu_throw(). This may not be needed now as we are under schedlock.
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* Maybe we can just do a thread_stash() as thr_exit1 does.
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*/
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/* XXX
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* libthr expects its thread exit to return for the last
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* thread, meaning that the program is back to non-threaded
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* mode I guess. Because we do this (cpu_throw) unconditionally
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* here, they have their own version of it. (thr_exit1())
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* that doesn't do it all if this was the last thread.
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* It is also called from thread_suspend_check().
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* Of course in the end, they end up coming here through exit1
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* anyhow.. After fixing 'thr' to play by the rules we should be able
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* to merge these two functions together.
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*
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* called from:
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* exit1()
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* kse_exit()
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* thr_exit()
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* ifdef KSE
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* thread_user_enter()
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* thread_userret()
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* endif
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* thread_suspend_check()
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*/
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void
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thread_exit(void)
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{
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uint64_t new_switchtime;
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struct thread *td;
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struct thread *td2;
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struct proc *p;
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td = curthread;
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p = td->td_proc;
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PROC_SLOCK_ASSERT(p, MA_OWNED);
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mtx_assert(&Giant, MA_NOTOWNED);
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PROC_LOCK_ASSERT(p, MA_OWNED);
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KASSERT(p != NULL, ("thread exiting without a process"));
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CTR3(KTR_PROC, "thread_exit: thread %p (pid %ld, %s)", td,
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(long)p->p_pid, td->td_name);
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KASSERT(TAILQ_EMPTY(&td->td_sigqueue.sq_list), ("signal pending"));
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#ifdef AUDIT
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AUDIT_SYSCALL_EXIT(0, td);
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#endif
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#ifdef KSE
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if (td->td_standin != NULL) {
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/*
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* Note that we don't need to free the cred here as it
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* is done in thread_reap().
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*/
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thread_zombie(td->td_standin);
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td->td_standin = NULL;
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}
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#endif
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umtx_thread_exit(td);
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/*
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* drop FPU & debug register state storage, or any other
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* architecture specific resources that
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* would not be on a new untouched process.
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*/
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cpu_thread_exit(td); /* XXXSMP */
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/* Do the same timestamp bookkeeping that mi_switch() would do. */
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new_switchtime = cpu_ticks();
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p->p_rux.rux_runtime += (new_switchtime - PCPU_GET(switchtime));
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PCPU_SET(switchtime, new_switchtime);
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PCPU_SET(switchticks, ticks);
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PCPU_INC(cnt.v_swtch);
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/* Save our resource usage in our process. */
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td->td_ru.ru_nvcsw++;
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rucollect(&p->p_ru, &td->td_ru);
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/*
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* The last thread is left attached to the process
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* So that the whole bundle gets recycled. Skip
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* all this stuff if we never had threads.
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* EXIT clears all sign of other threads when
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* it goes to single threading, so the last thread always
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* takes the short path.
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*/
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if (p->p_flag & P_HADTHREADS) {
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if (p->p_numthreads > 1) {
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thread_lock(td);
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#ifdef KSE
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kse_unlink(td);
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#else
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thread_unlink(td);
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#endif
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thread_unlock(td);
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td2 = FIRST_THREAD_IN_PROC(p);
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sched_exit_thread(td2, td);
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|
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/*
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* The test below is NOT true if we are the
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* sole exiting thread. P_STOPPED_SNGL is unset
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* in exit1() after it is the only survivor.
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*/
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if (P_SHOULDSTOP(p) == P_STOPPED_SINGLE) {
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if (p->p_numthreads == p->p_suspcount) {
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thread_lock(p->p_singlethread);
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thread_unsuspend_one(p->p_singlethread);
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thread_unlock(p->p_singlethread);
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}
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}
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atomic_add_int(&td->td_proc->p_exitthreads, 1);
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PCPU_SET(deadthread, td);
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|
} else {
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/*
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|
* The last thread is exiting.. but not through exit()
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|
* what should we do?
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|
* Theoretically this can't happen
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|
* exit1() - clears threading flags before coming here
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|
* kse_exit() - treats last thread specially
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|
* thr_exit() - treats last thread specially
|
|
* ifdef KSE
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|
* thread_user_enter() - only if more exist
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|
* thread_userret() - only if more exist
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|
* endif
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* thread_suspend_check() - only if more exist
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*/
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panic ("thread_exit: Last thread exiting on its own");
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}
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}
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PROC_UNLOCK(p);
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thread_lock(td);
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/* Save our tick information with both the thread and proc locked */
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|
ruxagg(&p->p_rux, td);
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|
PROC_SUNLOCK(p);
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|
td->td_state = TDS_INACTIVE;
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|
CTR1(KTR_PROC, "thread_exit: cpu_throw() thread %p", td);
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sched_throw(td);
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|
panic("I'm a teapot!");
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|
/* NOTREACHED */
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|
}
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|
|
/*
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|
* Do any thread specific cleanups that may be needed in wait()
|
|
* called with Giant, proc and schedlock not held.
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|
*/
|
|
void
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thread_wait(struct proc *p)
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|
{
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|
struct thread *td;
|
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|
|
mtx_assert(&Giant, MA_NOTOWNED);
|
|
KASSERT((p->p_numthreads == 1), ("Multiple threads in wait1()"));
|
|
td = FIRST_THREAD_IN_PROC(p);
|
|
#ifdef KSE
|
|
if (td->td_standin != NULL) {
|
|
if (td->td_standin->td_ucred != NULL) {
|
|
crfree(td->td_standin->td_ucred);
|
|
td->td_standin->td_ucred = NULL;
|
|
}
|
|
thread_free(td->td_standin);
|
|
td->td_standin = NULL;
|
|
}
|
|
#endif
|
|
/* Lock the last thread so we spin until it exits cpu_throw(). */
|
|
thread_lock(td);
|
|
thread_unlock(td);
|
|
/* Wait for any remaining threads to exit cpu_throw(). */
|
|
while (p->p_exitthreads)
|
|
sched_relinquish(curthread);
|
|
cpuset_rel(td->td_cpuset);
|
|
td->td_cpuset = NULL;
|
|
cpu_thread_clean(td);
|
|
crfree(td->td_ucred);
|
|
thread_reap(); /* check for zombie threads etc. */
|
|
}
|
|
|
|
/*
|
|
* Link a thread to a process.
|
|
* set up anything that needs to be initialized for it to
|
|
* be used by the process.
|
|
*
|
|
* Note that we do not link to the proc's ucred here.
|
|
* The thread is linked as if running but no KSE assigned.
|
|
* Called from:
|
|
* proc_linkup()
|
|
* thread_schedule_upcall()
|
|
* thr_create()
|
|
*/
|
|
void
|
|
thread_link(struct thread *td, struct proc *p)
|
|
{
|
|
|
|
/*
|
|
* XXX This can't be enabled because it's called for proc0 before
|
|
* it's spinlock has been created.
|
|
* PROC_SLOCK_ASSERT(p, MA_OWNED);
|
|
*/
|
|
td->td_state = TDS_INACTIVE;
|
|
td->td_proc = p;
|
|
td->td_flags = TDF_INMEM;
|
|
|
|
LIST_INIT(&td->td_contested);
|
|
LIST_INIT(&td->td_lprof[0]);
|
|
LIST_INIT(&td->td_lprof[1]);
|
|
sigqueue_init(&td->td_sigqueue, p);
|
|
callout_init(&td->td_slpcallout, CALLOUT_MPSAFE);
|
|
TAILQ_INSERT_HEAD(&p->p_threads, td, td_plist);
|
|
p->p_numthreads++;
|
|
}
|
|
|
|
/*
|
|
* Convert a process with one thread to an unthreaded process.
|
|
* Called from:
|
|
* thread_single(exit) (called from execve and exit)
|
|
* kse_exit() XXX may need cleaning up wrt KSE stuff
|
|
*/
|
|
void
|
|
thread_unthread(struct thread *td)
|
|
{
|
|
struct proc *p = td->td_proc;
|
|
|
|
KASSERT((p->p_numthreads == 1), ("Unthreading with >1 threads"));
|
|
#ifdef KSE
|
|
thread_lock(td);
|
|
upcall_remove(td);
|
|
thread_unlock(td);
|
|
p->p_flag &= ~(P_SA|P_HADTHREADS);
|
|
td->td_mailbox = NULL;
|
|
td->td_pflags &= ~(TDP_SA | TDP_CAN_UNBIND);
|
|
if (td->td_standin != NULL) {
|
|
thread_zombie(td->td_standin);
|
|
td->td_standin = NULL;
|
|
}
|
|
#else
|
|
p->p_flag &= ~P_HADTHREADS;
|
|
#endif
|
|
}
|
|
|
|
/*
|
|
* Called from:
|
|
* thread_exit()
|
|
*/
|
|
void
|
|
thread_unlink(struct thread *td)
|
|
{
|
|
struct proc *p = td->td_proc;
|
|
|
|
PROC_SLOCK_ASSERT(p, MA_OWNED);
|
|
TAILQ_REMOVE(&p->p_threads, td, td_plist);
|
|
p->p_numthreads--;
|
|
/* could clear a few other things here */
|
|
/* Must NOT clear links to proc! */
|
|
}
|
|
|
|
/*
|
|
* Enforce single-threading.
|
|
*
|
|
* Returns 1 if the caller must abort (another thread is waiting to
|
|
* exit the process or similar). Process is locked!
|
|
* Returns 0 when you are successfully the only thread running.
|
|
* A process has successfully single threaded in the suspend mode when
|
|
* There are no threads in user mode. Threads in the kernel must be
|
|
* allowed to continue until they get to the user boundary. They may even
|
|
* copy out their return values and data before suspending. They may however be
|
|
* accelerated in reaching the user boundary as we will wake up
|
|
* any sleeping threads that are interruptable. (PCATCH).
|
|
*/
|
|
int
|
|
thread_single(int mode)
|
|
{
|
|
struct thread *td;
|
|
struct thread *td2;
|
|
struct proc *p;
|
|
int remaining;
|
|
|
|
td = curthread;
|
|
p = td->td_proc;
|
|
mtx_assert(&Giant, MA_NOTOWNED);
|
|
PROC_LOCK_ASSERT(p, MA_OWNED);
|
|
KASSERT((td != NULL), ("curthread is NULL"));
|
|
|
|
if ((p->p_flag & P_HADTHREADS) == 0)
|
|
return (0);
|
|
|
|
/* Is someone already single threading? */
|
|
if (p->p_singlethread != NULL && p->p_singlethread != td)
|
|
return (1);
|
|
|
|
if (mode == SINGLE_EXIT) {
|
|
p->p_flag |= P_SINGLE_EXIT;
|
|
p->p_flag &= ~P_SINGLE_BOUNDARY;
|
|
} else {
|
|
p->p_flag &= ~P_SINGLE_EXIT;
|
|
if (mode == SINGLE_BOUNDARY)
|
|
p->p_flag |= P_SINGLE_BOUNDARY;
|
|
else
|
|
p->p_flag &= ~P_SINGLE_BOUNDARY;
|
|
}
|
|
p->p_flag |= P_STOPPED_SINGLE;
|
|
PROC_SLOCK(p);
|
|
p->p_singlethread = td;
|
|
if (mode == SINGLE_EXIT)
|
|
remaining = p->p_numthreads;
|
|
else if (mode == SINGLE_BOUNDARY)
|
|
remaining = p->p_numthreads - p->p_boundary_count;
|
|
else
|
|
remaining = p->p_numthreads - p->p_suspcount;
|
|
while (remaining != 1) {
|
|
if (P_SHOULDSTOP(p) != P_STOPPED_SINGLE)
|
|
goto stopme;
|
|
FOREACH_THREAD_IN_PROC(p, td2) {
|
|
if (td2 == td)
|
|
continue;
|
|
thread_lock(td2);
|
|
td2->td_flags |= TDF_ASTPENDING;
|
|
if (TD_IS_INHIBITED(td2)) {
|
|
switch (mode) {
|
|
case SINGLE_EXIT:
|
|
if (td->td_flags & TDF_DBSUSPEND)
|
|
td->td_flags &= ~TDF_DBSUSPEND;
|
|
if (TD_IS_SUSPENDED(td2))
|
|
thread_unsuspend_one(td2);
|
|
if (TD_ON_SLEEPQ(td2) &&
|
|
(td2->td_flags & TDF_SINTR))
|
|
sleepq_abort(td2, EINTR);
|
|
break;
|
|
case SINGLE_BOUNDARY:
|
|
break;
|
|
default:
|
|
if (TD_IS_SUSPENDED(td2)) {
|
|
thread_unlock(td2);
|
|
continue;
|
|
}
|
|
/*
|
|
* maybe other inhibited states too?
|
|
*/
|
|
if ((td2->td_flags & TDF_SINTR) &&
|
|
(td2->td_inhibitors &
|
|
(TDI_SLEEPING | TDI_SWAPPED)))
|
|
thread_suspend_one(td2);
|
|
break;
|
|
}
|
|
}
|
|
#ifdef SMP
|
|
else if (TD_IS_RUNNING(td2) && td != td2) {
|
|
forward_signal(td2);
|
|
}
|
|
#endif
|
|
thread_unlock(td2);
|
|
}
|
|
if (mode == SINGLE_EXIT)
|
|
remaining = p->p_numthreads;
|
|
else if (mode == SINGLE_BOUNDARY)
|
|
remaining = p->p_numthreads - p->p_boundary_count;
|
|
else
|
|
remaining = p->p_numthreads - p->p_suspcount;
|
|
|
|
/*
|
|
* Maybe we suspended some threads.. was it enough?
|
|
*/
|
|
if (remaining == 1)
|
|
break;
|
|
|
|
stopme:
|
|
/*
|
|
* Wake us up when everyone else has suspended.
|
|
* In the mean time we suspend as well.
|
|
*/
|
|
thread_suspend_switch(td);
|
|
if (mode == SINGLE_EXIT)
|
|
remaining = p->p_numthreads;
|
|
else if (mode == SINGLE_BOUNDARY)
|
|
remaining = p->p_numthreads - p->p_boundary_count;
|
|
else
|
|
remaining = p->p_numthreads - p->p_suspcount;
|
|
}
|
|
if (mode == SINGLE_EXIT) {
|
|
/*
|
|
* We have gotten rid of all the other threads and we
|
|
* are about to either exit or exec. In either case,
|
|
* we try our utmost to revert to being a non-threaded
|
|
* process.
|
|
*/
|
|
p->p_singlethread = NULL;
|
|
p->p_flag &= ~(P_STOPPED_SINGLE | P_SINGLE_EXIT);
|
|
thread_unthread(td);
|
|
}
|
|
PROC_SUNLOCK(p);
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* Called in from locations that can safely check to see
|
|
* whether we have to suspend or at least throttle for a
|
|
* single-thread event (e.g. fork).
|
|
*
|
|
* Such locations include userret().
|
|
* If the "return_instead" argument is non zero, the thread must be able to
|
|
* accept 0 (caller may continue), or 1 (caller must abort) as a result.
|
|
*
|
|
* The 'return_instead' argument tells the function if it may do a
|
|
* thread_exit() or suspend, or whether the caller must abort and back
|
|
* out instead.
|
|
*
|
|
* If the thread that set the single_threading request has set the
|
|
* P_SINGLE_EXIT bit in the process flags then this call will never return
|
|
* if 'return_instead' is false, but will exit.
|
|
*
|
|
* P_SINGLE_EXIT | return_instead == 0| return_instead != 0
|
|
*---------------+--------------------+---------------------
|
|
* 0 | returns 0 | returns 0 or 1
|
|
* | when ST ends | immediatly
|
|
*---------------+--------------------+---------------------
|
|
* 1 | thread exits | returns 1
|
|
* | | immediatly
|
|
* 0 = thread_exit() or suspension ok,
|
|
* other = return error instead of stopping the thread.
|
|
*
|
|
* While a full suspension is under effect, even a single threading
|
|
* thread would be suspended if it made this call (but it shouldn't).
|
|
* This call should only be made from places where
|
|
* thread_exit() would be safe as that may be the outcome unless
|
|
* return_instead is set.
|
|
*/
|
|
int
|
|
thread_suspend_check(int return_instead)
|
|
{
|
|
struct thread *td;
|
|
struct proc *p;
|
|
|
|
td = curthread;
|
|
p = td->td_proc;
|
|
mtx_assert(&Giant, MA_NOTOWNED);
|
|
PROC_LOCK_ASSERT(p, MA_OWNED);
|
|
while (P_SHOULDSTOP(p) ||
|
|
((p->p_flag & P_TRACED) && (td->td_flags & TDF_DBSUSPEND))) {
|
|
if (P_SHOULDSTOP(p) == P_STOPPED_SINGLE) {
|
|
KASSERT(p->p_singlethread != NULL,
|
|
("singlethread not set"));
|
|
/*
|
|
* The only suspension in action is a
|
|
* single-threading. Single threader need not stop.
|
|
* XXX Should be safe to access unlocked
|
|
* as it can only be set to be true by us.
|
|
*/
|
|
if (p->p_singlethread == td)
|
|
return (0); /* Exempt from stopping. */
|
|
}
|
|
if ((p->p_flag & P_SINGLE_EXIT) && return_instead)
|
|
return (EINTR);
|
|
|
|
/* Should we goto user boundary if we didn't come from there? */
|
|
if (P_SHOULDSTOP(p) == P_STOPPED_SINGLE &&
|
|
(p->p_flag & P_SINGLE_BOUNDARY) && return_instead)
|
|
return (ERESTART);
|
|
|
|
/* If thread will exit, flush its pending signals */
|
|
if ((p->p_flag & P_SINGLE_EXIT) && (p->p_singlethread != td))
|
|
sigqueue_flush(&td->td_sigqueue);
|
|
|
|
PROC_SLOCK(p);
|
|
thread_stopped(p);
|
|
/*
|
|
* If the process is waiting for us to exit,
|
|
* this thread should just suicide.
|
|
* Assumes that P_SINGLE_EXIT implies P_STOPPED_SINGLE.
|
|
*/
|
|
if ((p->p_flag & P_SINGLE_EXIT) && (p->p_singlethread != td))
|
|
thread_exit();
|
|
if (P_SHOULDSTOP(p) == P_STOPPED_SINGLE) {
|
|
if (p->p_numthreads == p->p_suspcount + 1) {
|
|
thread_lock(p->p_singlethread);
|
|
thread_unsuspend_one(p->p_singlethread);
|
|
thread_unlock(p->p_singlethread);
|
|
}
|
|
}
|
|
PROC_UNLOCK(p);
|
|
thread_lock(td);
|
|
/*
|
|
* When a thread suspends, it just
|
|
* gets taken off all queues.
|
|
*/
|
|
thread_suspend_one(td);
|
|
if (return_instead == 0) {
|
|
p->p_boundary_count++;
|
|
td->td_flags |= TDF_BOUNDARY;
|
|
}
|
|
PROC_SUNLOCK(p);
|
|
mi_switch(SW_INVOL, NULL);
|
|
if (return_instead == 0)
|
|
td->td_flags &= ~TDF_BOUNDARY;
|
|
thread_unlock(td);
|
|
PROC_LOCK(p);
|
|
if (return_instead == 0)
|
|
p->p_boundary_count--;
|
|
}
|
|
return (0);
|
|
}
|
|
|
|
void
|
|
thread_suspend_switch(struct thread *td)
|
|
{
|
|
struct proc *p;
|
|
|
|
p = td->td_proc;
|
|
KASSERT(!TD_IS_SUSPENDED(td), ("already suspended"));
|
|
PROC_LOCK_ASSERT(p, MA_OWNED);
|
|
PROC_SLOCK_ASSERT(p, MA_OWNED);
|
|
/*
|
|
* We implement thread_suspend_one in stages here to avoid
|
|
* dropping the proc lock while the thread lock is owned.
|
|
*/
|
|
thread_stopped(p);
|
|
p->p_suspcount++;
|
|
PROC_UNLOCK(p);
|
|
thread_lock(td);
|
|
sched_sleep(td);
|
|
TD_SET_SUSPENDED(td);
|
|
PROC_SUNLOCK(p);
|
|
DROP_GIANT();
|
|
mi_switch(SW_VOL, NULL);
|
|
thread_unlock(td);
|
|
PICKUP_GIANT();
|
|
PROC_LOCK(p);
|
|
PROC_SLOCK(p);
|
|
}
|
|
|
|
void
|
|
thread_suspend_one(struct thread *td)
|
|
{
|
|
struct proc *p = td->td_proc;
|
|
|
|
PROC_SLOCK_ASSERT(p, MA_OWNED);
|
|
THREAD_LOCK_ASSERT(td, MA_OWNED);
|
|
KASSERT(!TD_IS_SUSPENDED(td), ("already suspended"));
|
|
p->p_suspcount++;
|
|
sched_sleep(td);
|
|
TD_SET_SUSPENDED(td);
|
|
}
|
|
|
|
void
|
|
thread_unsuspend_one(struct thread *td)
|
|
{
|
|
struct proc *p = td->td_proc;
|
|
|
|
PROC_SLOCK_ASSERT(p, MA_OWNED);
|
|
THREAD_LOCK_ASSERT(td, MA_OWNED);
|
|
KASSERT(TD_IS_SUSPENDED(td), ("Thread not suspended"));
|
|
TD_CLR_SUSPENDED(td);
|
|
p->p_suspcount--;
|
|
setrunnable(td);
|
|
}
|
|
|
|
/*
|
|
* Allow all threads blocked by single threading to continue running.
|
|
*/
|
|
void
|
|
thread_unsuspend(struct proc *p)
|
|
{
|
|
struct thread *td;
|
|
|
|
PROC_LOCK_ASSERT(p, MA_OWNED);
|
|
PROC_SLOCK_ASSERT(p, MA_OWNED);
|
|
if (!P_SHOULDSTOP(p)) {
|
|
FOREACH_THREAD_IN_PROC(p, td) {
|
|
thread_lock(td);
|
|
if (TD_IS_SUSPENDED(td)) {
|
|
thread_unsuspend_one(td);
|
|
}
|
|
thread_unlock(td);
|
|
}
|
|
} else if ((P_SHOULDSTOP(p) == P_STOPPED_SINGLE) &&
|
|
(p->p_numthreads == p->p_suspcount)) {
|
|
/*
|
|
* Stopping everything also did the job for the single
|
|
* threading request. Now we've downgraded to single-threaded,
|
|
* let it continue.
|
|
*/
|
|
thread_lock(p->p_singlethread);
|
|
thread_unsuspend_one(p->p_singlethread);
|
|
thread_unlock(p->p_singlethread);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* End the single threading mode..
|
|
*/
|
|
void
|
|
thread_single_end(void)
|
|
{
|
|
struct thread *td;
|
|
struct proc *p;
|
|
|
|
td = curthread;
|
|
p = td->td_proc;
|
|
PROC_LOCK_ASSERT(p, MA_OWNED);
|
|
p->p_flag &= ~(P_STOPPED_SINGLE | P_SINGLE_EXIT | P_SINGLE_BOUNDARY);
|
|
PROC_SLOCK(p);
|
|
p->p_singlethread = NULL;
|
|
/*
|
|
* If there are other threads they mey now run,
|
|
* unless of course there is a blanket 'stop order'
|
|
* on the process. The single threader must be allowed
|
|
* to continue however as this is a bad place to stop.
|
|
*/
|
|
if ((p->p_numthreads != 1) && (!P_SHOULDSTOP(p))) {
|
|
FOREACH_THREAD_IN_PROC(p, td) {
|
|
thread_lock(td);
|
|
if (TD_IS_SUSPENDED(td)) {
|
|
thread_unsuspend_one(td);
|
|
}
|
|
thread_unlock(td);
|
|
}
|
|
}
|
|
PROC_SUNLOCK(p);
|
|
}
|
|
|
|
struct thread *
|
|
thread_find(struct proc *p, lwpid_t tid)
|
|
{
|
|
struct thread *td;
|
|
|
|
PROC_LOCK_ASSERT(p, MA_OWNED);
|
|
PROC_SLOCK(p);
|
|
FOREACH_THREAD_IN_PROC(p, td) {
|
|
if (td->td_tid == tid)
|
|
break;
|
|
}
|
|
PROC_SUNLOCK(p);
|
|
return (td);
|
|
}
|