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169 lines
3.9 KiB
C
169 lines
3.9 KiB
C
/* $NetBSD: klock.c,v 1.8 2013/04/30 00:03:53 pooka Exp $ */
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/*
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* Copyright (c) 2007-2010 Antti Kantee. All Rights Reserved.
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*
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* Development of this software was supported by the
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* Finnish Cultural Foundation.
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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, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, 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 AUTHOR ``AS IS'' AND ANY EXPRESS
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* 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 AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER 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
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: klock.c,v 1.8 2013/04/30 00:03:53 pooka Exp $");
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/evcnt.h>
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#include <rump/rumpuser.h>
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#include "rump_private.h"
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/*
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* giant lock
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*/
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struct rumpuser_mtx *rump_giantlock;
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static int giantcnt;
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static struct lwp *giantowner;
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static struct evcnt ev_biglock_fast;
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static struct evcnt ev_biglock_slow;
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static struct evcnt ev_biglock_recurse;
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void
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rump_biglock_init(void)
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{
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evcnt_attach_dynamic(&ev_biglock_fast, EVCNT_TYPE_MISC, NULL,
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"rump biglock", "fast");
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evcnt_attach_dynamic(&ev_biglock_slow, EVCNT_TYPE_MISC, NULL,
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"rump biglock", "slow");
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evcnt_attach_dynamic(&ev_biglock_recurse, EVCNT_TYPE_MISC, NULL,
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"rump biglock", "recurse");
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}
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void
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rump_kernel_bigwrap(int *nlocks)
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{
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KASSERT(giantcnt > 0 && curlwp == giantowner);
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giantowner = NULL;
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*nlocks = giantcnt;
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giantcnt = 0;
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}
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void
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rump_kernel_bigunwrap(int nlocks)
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{
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KASSERT(giantowner == NULL);
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giantowner = curlwp;
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giantcnt = nlocks;
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}
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void
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_kernel_lock(int nlocks)
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{
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struct lwp *l = curlwp;
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while (nlocks) {
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if (giantowner == l) {
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giantcnt += nlocks;
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nlocks = 0;
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ev_biglock_recurse.ev_count++;
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} else {
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if (rumpuser_mutex_tryenter(rump_giantlock) != 0) {
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rump_unschedule_cpu1(l, NULL);
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rumpuser_mutex_enter_nowrap(rump_giantlock);
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rump_schedule_cpu(l);
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ev_biglock_slow.ev_count++;
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} else {
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ev_biglock_fast.ev_count++;
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}
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giantowner = l;
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giantcnt = 1;
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nlocks--;
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}
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}
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}
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void
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_kernel_unlock(int nlocks, int *countp)
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{
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if (giantowner != curlwp) {
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KASSERT(nlocks == 0);
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if (countp)
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*countp = 0;
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return;
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}
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if (countp)
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*countp = giantcnt;
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if (nlocks == 0)
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nlocks = giantcnt;
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if (nlocks == -1) {
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KASSERT(giantcnt == 1);
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nlocks = 1;
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}
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KASSERT(nlocks <= giantcnt);
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while (nlocks--) {
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giantcnt--;
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}
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if (giantcnt == 0) {
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giantowner = NULL;
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rumpuser_mutex_exit(rump_giantlock);
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}
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}
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bool
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_kernel_locked_p(void)
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{
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return giantowner == curlwp;
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}
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void
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rump_user_unschedule(int nlocks, int *countp, void *interlock)
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{
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_kernel_unlock(nlocks, countp);
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/*
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* XXX: technically we should unschedule_cpu1() here, but that
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* requires rump_intr_enter/exit to be implemented.
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*/
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rump_unschedule_cpu_interlock(curlwp, interlock);
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}
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void
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rump_user_schedule(int nlocks, void *interlock)
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{
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rump_schedule_cpu_interlock(curlwp, interlock);
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if (nlocks)
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_kernel_lock(nlocks);
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}
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