freebsd-dev/sys/kern/subr_trap.c
Julian Elischer 93a7aa79d6 Add code to ddb to allow backtracing an arbitrary thread.
(show thread {address})

Remove the IDLE kse state and replace it with a change in
the way threads sahre KSEs. Every KSE now has a thread, which is
considered its "owner" however a KSE may also be lent to other
threads in the same group to allow completion of in-kernel work.
n this case the owner remains the same and the KSE will revert to the
owner when the other work has been completed.

All creations of upcalls etc. is now done from
kse_reassign() which in turn is called from mi_switch or
thread_exit(). This means that special code can be removed from
msleep() and cv_wait().

kse_release() does not leave a KSE with no thread any more but
converts the existing thread into teh KSE's owner, and sets it up
for doing an upcall. It is just inhibitted from being scheduled until
there is some reason to do an upcall.

Remove all trace of the kse_idle queue since it is no-longer needed.
"Idle" KSEs are now on the loanable queue.
2002-12-28 01:23:07 +00:00

263 lines
7.2 KiB
C

/*-
* Copyright (C) 1994, David Greenman
* Copyright (c) 1990, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* the University of Utah, and William Jolitz.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* from: @(#)trap.c 7.4 (Berkeley) 5/13/91
* $FreeBSD$
*/
#include "opt_mac.h"
#ifdef __i386__
#include "opt_npx.h"
#endif
#include <sys/param.h>
#include <sys/bus.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/mac.h>
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/kse.h>
#include <sys/ktr.h>
#include <sys/resourcevar.h>
#include <sys/sched.h>
#include <sys/signalvar.h>
#include <sys/systm.h>
#include <sys/vmmeter.h>
#include <machine/cpu.h>
#include <machine/pcb.h>
/*
* Define the code needed before returning to user mode, for
* trap and syscall.
*
* MPSAFE
*/
void
userret(td, frame, oticks)
struct thread *td;
struct trapframe *frame;
u_int oticks;
{
struct proc *p = td->td_proc;
struct kse *ke = td->td_kse;
CTR3(KTR_SYSC, "userret: thread %p (pid %d, %s)", td, p->p_pid,
p->p_comm);
#ifdef INVARIANTS
/* Check that we called signotify() enough. */
mtx_lock(&Giant);
PROC_LOCK(p);
mtx_lock_spin(&sched_lock);
if (SIGPENDING(p) && ((p->p_sflag & PS_NEEDSIGCHK) == 0 ||
(td->td_kse->ke_flags & KEF_ASTPENDING) == 0))
printf("failed to set signal flags properly for ast()\n");
mtx_unlock_spin(&sched_lock);
PROC_UNLOCK(p);
mtx_unlock(&Giant);
#endif
/*
* Let the scheduler adjust our priority etc.
*/
sched_userret(td);
/*
* We need to check to see if we have to exit or wait due to a
* single threading requirement or some other STOP condition.
* Don't bother doing all the work if the stop bits are not set
* at this time.. If we miss it, we miss it.. no big deal.
*/
if (P_SHOULDSTOP(p)) {
PROC_LOCK(p);
thread_suspend_check(0); /* Can suspend or kill */
PROC_UNLOCK(p);
}
/*
* Do special thread processing, e.g. upcall tweaking and such.
*/
if (p->p_flag & P_KSES) {
thread_userret(td, frame);
}
/*
* Charge system time if profiling.
*
* XXX should move PS_PROFIL to a place that can obviously be
* accessed safely without sched_lock.
*/
if (p->p_sflag & PS_PROFIL) {
quad_t ticks;
mtx_lock_spin(&sched_lock);
ticks = ke->ke_sticks - oticks;
mtx_unlock_spin(&sched_lock);
addupc_task(ke, TRAPF_PC(frame), (u_int)ticks * psratio);
}
}
/*
* Process an asynchronous software trap.
* This is relatively easy.
* This function will return with preemption disabled.
*/
void
ast(struct trapframe *framep)
{
struct thread *td;
struct proc *p;
struct kse *ke;
struct ksegrp *kg;
struct rlimit *rlim;
u_int prticks, sticks;
int sflag;
int flags;
int sig;
#if defined(DEV_NPX) && !defined(SMP)
int ucode;
#endif
td = curthread;
p = td->td_proc;
kg = td->td_ksegrp;
CTR3(KTR_SYSC, "ast: thread %p (pid %d, %s)", td, p->p_pid,
p->p_comm);
KASSERT(TRAPF_USERMODE(framep), ("ast in kernel mode"));
#ifdef WITNESS
if (witness_list(td))
panic("Returning to user mode with mutex(s) held");
#endif
mtx_assert(&Giant, MA_NOTOWNED);
mtx_assert(&sched_lock, MA_NOTOWNED);
td->td_frame = framep;
/*
* This updates the p_sflag's for the checks below in one
* "atomic" operation with turning off the astpending flag.
* If another AST is triggered while we are handling the
* AST's saved in sflag, the astpending flag will be set and
* ast() will be called again.
*/
mtx_lock_spin(&sched_lock);
ke = td->td_kse;
sticks = ke->ke_sticks;
flags = ke->ke_flags;
sflag = p->p_sflag;
p->p_sflag &= ~(PS_ALRMPEND | PS_NEEDSIGCHK | PS_PROFPEND | PS_XCPU);
#ifdef MAC
p->p_sflag &= ~PS_MACPEND;
#endif
ke->ke_flags &= ~(KEF_ASTPENDING | KEF_NEEDRESCHED | KEF_OWEUPC);
cnt.v_soft++;
prticks = 0;
if (flags & KEF_OWEUPC && sflag & PS_PROFIL) {
prticks = p->p_stats->p_prof.pr_ticks;
p->p_stats->p_prof.pr_ticks = 0;
}
mtx_unlock_spin(&sched_lock);
/*
* XXXKSE While the fact that we owe a user profiling
* tick is stored per KSE in this code, the statistics
* themselves are still stored per process.
* This should probably change, by which I mean that
* possibly the location of both might change.
*/
if (td->td_ucred != p->p_ucred)
cred_update_thread(td);
if (flags & KEF_OWEUPC && sflag & PS_PROFIL)
addupc_task(ke, p->p_stats->p_prof.pr_addr, prticks);
if (sflag & PS_ALRMPEND) {
PROC_LOCK(p);
psignal(p, SIGVTALRM);
PROC_UNLOCK(p);
}
#if defined(DEV_NPX) && !defined(SMP)
if (PCPU_GET(curpcb)->pcb_flags & PCB_NPXTRAP) {
atomic_clear_int(&PCPU_GET(curpcb)->pcb_flags,
PCB_NPXTRAP);
ucode = npxtrap();
if (ucode != -1) {
trapsignal(p, SIGFPE, ucode);
}
}
#endif
if (sflag & PS_PROFPEND) {
PROC_LOCK(p);
psignal(p, SIGPROF);
PROC_UNLOCK(p);
}
if (sflag & PS_XCPU) {
PROC_LOCK(p);
rlim = &p->p_rlimit[RLIMIT_CPU];
if (p->p_runtime.sec >= rlim->rlim_max)
killproc(p, "exceeded maximum CPU limit");
else {
psignal(p, SIGXCPU);
mtx_lock_spin(&sched_lock);
if (p->p_cpulimit < rlim->rlim_max)
p->p_cpulimit += 5;
mtx_unlock_spin(&sched_lock);
}
PROC_UNLOCK(p);
}
#ifdef MAC
if (sflag & PS_MACPEND)
mac_thread_userret(td);
#endif
if (flags & KEF_NEEDRESCHED) {
mtx_lock_spin(&sched_lock);
sched_prio(td, kg->kg_user_pri);
p->p_stats->p_ru.ru_nivcsw++;
mi_switch();
mtx_unlock_spin(&sched_lock);
}
if (sflag & PS_NEEDSIGCHK) {
PROC_LOCK(p);
while ((sig = cursig(td)) != 0)
postsig(sig);
PROC_UNLOCK(p);
}
userret(td, framep, sticks);
#ifdef DIAGNOSTIC
cred_free_thread(td);
#endif
mtx_assert(&Giant, MA_NOTOWNED);
}