124 lines
2.8 KiB
C
124 lines
2.8 KiB
C
/*-
|
|
* Copyright (c) 1994 John Dyson
|
|
* Copyright (c) 2001 Matt Dillon
|
|
*
|
|
* All rights reserved. Terms for use and redistribution
|
|
* are covered by the BSD Copyright as found in /usr/src/COPYRIGHT.
|
|
*
|
|
* from: @(#)vm_machdep.c 7.3 (Berkeley) 5/13/91
|
|
* Utah $Hdr: vm_machdep.c 1.16.1.1 89/06/23$
|
|
* $FreeBSD$
|
|
*/
|
|
|
|
#ifndef __alpha__
|
|
#include "opt_npx.h"
|
|
#ifdef PC98
|
|
#include "opt_pc98.h"
|
|
#endif
|
|
#include "opt_reset.h"
|
|
#include "opt_isa.h"
|
|
#endif
|
|
|
|
#include <sys/param.h>
|
|
#include <sys/systm.h>
|
|
#include <sys/malloc.h>
|
|
#include <sys/proc.h>
|
|
#include <sys/bio.h>
|
|
#include <sys/buf.h>
|
|
#include <sys/vnode.h>
|
|
#include <sys/vmmeter.h>
|
|
#include <sys/kernel.h>
|
|
#include <sys/ktr.h>
|
|
#include <sys/mutex.h>
|
|
#include <sys/smp.h>
|
|
#include <sys/sysctl.h>
|
|
#include <sys/unistd.h>
|
|
|
|
#include <machine/cpu.h>
|
|
#include <machine/md_var.h>
|
|
#include <machine/pcb.h>
|
|
#ifndef __alpha__
|
|
#include <machine/pcb_ext.h>
|
|
#include <machine/vm86.h>
|
|
#endif
|
|
|
|
#include <vm/vm.h>
|
|
#include <vm/vm_param.h>
|
|
#include <sys/lock.h>
|
|
#include <vm/vm_kern.h>
|
|
#include <vm/vm_page.h>
|
|
#include <vm/vm_map.h>
|
|
#include <vm/vm_extern.h>
|
|
|
|
#include <sys/user.h>
|
|
|
|
#ifndef __alpha__
|
|
#ifdef PC98
|
|
#include <pc98/pc98/pc98.h>
|
|
#else
|
|
#include <i386/isa/isa.h>
|
|
#endif
|
|
#endif
|
|
|
|
SYSCTL_DECL(_vm_stats_misc);
|
|
|
|
static int cnt_prezero;
|
|
|
|
SYSCTL_INT(_vm_stats_misc, OID_AUTO,
|
|
cnt_prezero, CTLFLAG_RD, &cnt_prezero, 0, "");
|
|
|
|
/*
|
|
* Implement the pre-zeroed page mechanism.
|
|
* This routine is called from the idle loop.
|
|
*/
|
|
|
|
#define ZIDLE_LO(v) ((v) * 2 / 3)
|
|
#define ZIDLE_HI(v) ((v) * 4 / 5)
|
|
|
|
int
|
|
vm_page_zero_idle(void)
|
|
{
|
|
static int free_rover;
|
|
static int zero_state;
|
|
vm_page_t m;
|
|
|
|
/*
|
|
* Attempt to maintain approximately 1/2 of our free pages in a
|
|
* PG_ZERO'd state. Add some hysteresis to (attempt to) avoid
|
|
* generally zeroing a page when the system is near steady-state.
|
|
* Otherwise we might get 'flutter' during disk I/O / IPC or
|
|
* fast sleeps. We also do not want to be continuously zeroing
|
|
* pages because doing so may flush our L1 and L2 caches too much.
|
|
*/
|
|
|
|
if (zero_state && vm_page_zero_count >= ZIDLE_LO(cnt.v_free_count))
|
|
return(0);
|
|
if (vm_page_zero_count >= ZIDLE_HI(cnt.v_free_count))
|
|
return(0);
|
|
|
|
if (mtx_trylock(&Giant)) {
|
|
zero_state = 0;
|
|
m = vm_pageq_find(PQ_FREE, free_rover, FALSE);
|
|
if (m != NULL && (m->flags & PG_ZERO) == 0) {
|
|
vm_page_queues[m->queue].lcnt--;
|
|
TAILQ_REMOVE(&vm_page_queues[m->queue].pl, m, pageq);
|
|
m->queue = PQ_NONE;
|
|
pmap_zero_page(VM_PAGE_TO_PHYS(m));
|
|
vm_page_flag_set(m, PG_ZERO);
|
|
m->queue = PQ_FREE + m->pc;
|
|
vm_page_queues[m->queue].lcnt++;
|
|
TAILQ_INSERT_TAIL(&vm_page_queues[m->queue].pl, m,
|
|
pageq);
|
|
++vm_page_zero_count;
|
|
++cnt_prezero;
|
|
if (vm_page_zero_count >= ZIDLE_HI(cnt.v_free_count))
|
|
zero_state = 1;
|
|
}
|
|
free_rover = (free_rover + PQ_PRIME2) & PQ_L2_MASK;
|
|
mtx_unlock(&Giant);
|
|
return (1);
|
|
}
|
|
return(0);
|
|
}
|
|
|