51d643caa6
to kproc_xxx as they actually make whole processes. Thos makes way for us to add REAL kthread_create() and friends that actually make theads. it turns out that most of these calls actually end up being moved back to the thread version when it's added. but we need to make this cosmetic change first. I'd LOVE to do this rename in 7.0 so that we can eventually MFC the new kthread_xxx() calls.
168 lines
4.7 KiB
C
168 lines
4.7 KiB
C
/*-
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* Copyright (c) 1994 John Dyson
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* Copyright (c) 2001 Matt Dillon
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*
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* All Rights Reserved.
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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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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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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
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
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* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
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* GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* from: @(#)vm_machdep.c 7.3 (Berkeley) 5/13/91
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* Utah $Hdr: vm_machdep.c 1.16.1.1 89/06/23$
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* from: FreeBSD: .../i386/vm_machdep.c,v 1.165 2001/07/04 23:27:04 dillon
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <opt_sched.h>
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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/proc.h>
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#include <sys/vmmeter.h>
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#include <sys/lock.h>
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#include <sys/mutex.h>
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#include <sys/sched.h>
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#include <sys/sysctl.h>
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#include <sys/kthread.h>
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#include <sys/unistd.h>
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#include <vm/vm.h>
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#include <vm/vm_page.h>
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#include <vm/vm_phys.h>
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static int idlezero_enable_default = 0;
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TUNABLE_INT("vm.idlezero_enable", &idlezero_enable_default);
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/* Defer setting the enable flag until the kthread is running. */
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static int idlezero_enable = 0;
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SYSCTL_INT(_vm, OID_AUTO, idlezero_enable, CTLFLAG_RW, &idlezero_enable, 0, "");
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/*
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* Implement the pre-zeroed page mechanism.
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*/
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#define ZIDLE_LO(v) ((v) * 2 / 3)
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#define ZIDLE_HI(v) ((v) * 4 / 5)
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static boolean_t wakeup_needed = FALSE;
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static int zero_state;
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static int
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vm_page_zero_check(void)
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{
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if (!idlezero_enable)
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return (0);
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/*
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* Attempt to maintain approximately 1/2 of our free pages in a
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* PG_ZERO'd state. Add some hysteresis to (attempt to) avoid
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* generally zeroing a page when the system is near steady-state.
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* Otherwise we might get 'flutter' during disk I/O / IPC or
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* fast sleeps. We also do not want to be continuously zeroing
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* pages because doing so may flush our L1 and L2 caches too much.
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*/
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if (zero_state && vm_page_zero_count >= ZIDLE_LO(cnt.v_free_count))
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return (0);
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if (vm_page_zero_count >= ZIDLE_HI(cnt.v_free_count))
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return (0);
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return (1);
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}
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static void
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vm_page_zero_idle(void)
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{
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mtx_assert(&vm_page_queue_free_mtx, MA_OWNED);
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zero_state = 0;
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if (vm_phys_zero_pages_idle()) {
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if (vm_page_zero_count >= ZIDLE_HI(cnt.v_free_count))
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zero_state = 1;
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}
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}
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/* Called by vm_page_free to hint that a new page is available. */
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void
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vm_page_zero_idle_wakeup(void)
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{
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mtx_assert(&vm_page_queue_free_mtx, MA_OWNED);
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if (wakeup_needed && vm_page_zero_check()) {
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wakeup_needed = FALSE;
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wakeup(&zero_state);
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}
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}
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static void
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vm_pagezero(void __unused *arg)
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{
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idlezero_enable = idlezero_enable_default;
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mtx_lock(&vm_page_queue_free_mtx);
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for (;;) {
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if (vm_page_zero_check()) {
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vm_page_zero_idle();
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#ifndef PREEMPTION
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if (sched_runnable()) {
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thread_lock(curthread);
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mi_switch(SW_VOL, NULL);
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thread_unlock(curthread);
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}
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#endif
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} else {
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wakeup_needed = TRUE;
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msleep(&zero_state, &vm_page_queue_free_mtx, 0,
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"pgzero", hz * 300);
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}
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}
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}
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static struct proc *pagezero_proc;
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static void
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pagezero_start(void __unused *arg)
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{
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int error;
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struct thread *td;
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error = kproc_create(vm_pagezero, NULL, &pagezero_proc, RFSTOPPED, 0,
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"pagezero");
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if (error)
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panic("pagezero_start: error %d\n", error);
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/*
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* We're an idle task, don't count us in the load.
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*/
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PROC_LOCK(pagezero_proc);
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pagezero_proc->p_flag |= P_NOLOAD;
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PROC_UNLOCK(pagezero_proc);
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td = FIRST_THREAD_IN_PROC(pagezero_proc);
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thread_lock(td);
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sched_class(td, PRI_IDLE);
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sched_prio(td, PRI_MAX_IDLE);
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sched_add(td, SRQ_BORING);
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thread_unlock(td);
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}
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SYSINIT(pagezero, SI_SUB_KTHREAD_VM, SI_ORDER_ANY, pagezero_start, NULL)
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