1103 lines
27 KiB
C
1103 lines
27 KiB
C
/*
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* Copyright (c) 1991 Regents of the University of California.
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* All rights reserved.
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* Copyright (c) 1994 John S. Dyson
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* All rights reserved.
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* Copyright (c) 1994 David Greenman
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* All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* The Mach Operating System project at Carnegie-Mellon University.
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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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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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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 REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS 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
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* OR 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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* from: @(#)vm_pageout.c 7.4 (Berkeley) 5/7/91
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*
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*
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* Copyright (c) 1987, 1990 Carnegie-Mellon University.
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* All rights reserved.
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*
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* Authors: Avadis Tevanian, Jr., Michael Wayne Young
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*
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* Permission to use, copy, modify and distribute this software and
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* its documentation is hereby granted, provided that both the copyright
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* notice and this permission notice appear in all copies of the
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* software, derivative works or modified versions, and any portions
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* thereof, and that both notices appear in supporting documentation.
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*
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* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
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* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
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* FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
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*
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* Carnegie Mellon requests users of this software to return to
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*
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* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
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* School of Computer Science
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* Carnegie Mellon University
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* Pittsburgh PA 15213-3890
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*
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* any improvements or extensions that they make and grant Carnegie the
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* rights to redistribute these changes.
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*
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* $Id: vm_pageout.c,v 1.81 1996/07/08 02:25:53 dyson Exp $
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*/
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/*
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* The proverbial page-out daemon.
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*/
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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/resourcevar.h>
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#include <sys/malloc.h>
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#include <sys/kernel.h>
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#include <sys/signalvar.h>
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#include <sys/vnode.h>
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#include <sys/vmmeter.h>
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#include <sys/sysctl.h>
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#include <vm/vm.h>
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#include <vm/vm_param.h>
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#include <vm/vm_prot.h>
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#include <vm/lock.h>
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#include <vm/vm_object.h>
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#include <vm/vm_page.h>
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#include <vm/vm_map.h>
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#include <vm/vm_pageout.h>
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#include <vm/vm_kern.h>
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#include <vm/vm_pager.h>
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#include <vm/swap_pager.h>
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#include <vm/vm_extern.h>
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/*
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* System initialization
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*/
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/* the kernel process "vm_pageout"*/
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static void vm_pageout __P((void));
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static int vm_pageout_clean __P((vm_page_t, int));
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static int vm_pageout_scan __P((void));
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static int vm_pageout_free_page_calc __P((vm_size_t count));
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struct proc *pageproc;
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static struct kproc_desc page_kp = {
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"pagedaemon",
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vm_pageout,
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&pageproc
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};
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SYSINIT_KT(pagedaemon, SI_SUB_KTHREAD_PAGE, SI_ORDER_FIRST, kproc_start, &page_kp)
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#if !defined(NO_SWAPPING)
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/* the kernel process "vm_daemon"*/
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static void vm_daemon __P((void));
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static struct proc *vmproc;
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static struct kproc_desc vm_kp = {
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"vmdaemon",
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vm_daemon,
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&vmproc
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};
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SYSINIT_KT(vmdaemon, SI_SUB_KTHREAD_VM, SI_ORDER_FIRST, kproc_start, &vm_kp)
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#endif
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int vm_pages_needed; /* Event on which pageout daemon sleeps */
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int vm_pageout_pages_needed; /* flag saying that the pageout daemon needs pages */
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extern int npendingio;
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#if !defined(NO_SWAPPING)
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static int vm_pageout_req_swapout; /* XXX */
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static int vm_daemon_needed;
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#endif
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extern int nswiodone;
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extern int vm_swap_size;
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extern int vfs_update_wakeup;
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int vm_pageout_algorithm_lru=0;
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#if defined(NO_SWAPPING)
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int vm_swapping_enabled=0;
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#else
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int vm_swapping_enabled=1;
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#endif
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SYSCTL_INT(_vm, VM_PAGEOUT_ALGORITHM, pageout_algorithm,
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CTLFLAG_RW, &vm_pageout_algorithm_lru, 0, "");
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#if defined(NO_SWAPPING)
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SYSCTL_INT(_vm, VM_SWAPPING_ENABLED, swapping_enabled,
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CTLFLAG_RD, &vm_swapping_enabled, 0, "");
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#else
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SYSCTL_INT(_vm, VM_SWAPPING_ENABLED, swapping_enabled,
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CTLFLAG_RW, &vm_swapping_enabled, 0, "");
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#endif
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#define MAXLAUNDER (cnt.v_page_count > 1800 ? 32 : 16)
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#define VM_PAGEOUT_PAGE_COUNT 16
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int vm_pageout_page_count = VM_PAGEOUT_PAGE_COUNT;
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int vm_page_max_wired; /* XXX max # of wired pages system-wide */
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#if !defined(NO_SWAPPING)
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typedef void freeer_fcn_t __P((vm_map_t, vm_object_t, vm_pindex_t, int));
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static void vm_pageout_map_deactivate_pages __P((vm_map_t, vm_pindex_t));
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static freeer_fcn_t vm_pageout_object_deactivate_pages;
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static void vm_req_vmdaemon __P((void));
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#endif
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/*
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* vm_pageout_clean:
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*
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* Clean the page and remove it from the laundry.
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*
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* We set the busy bit to cause potential page faults on this page to
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* block.
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*
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* And we set pageout-in-progress to keep the object from disappearing
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* during pageout. This guarantees that the page won't move from the
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* inactive queue. (However, any other page on the inactive queue may
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* move!)
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*/
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static int
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vm_pageout_clean(m, sync)
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vm_page_t m;
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int sync;
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{
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register vm_object_t object;
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vm_page_t mc[2*vm_pageout_page_count];
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int pageout_count;
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int i, forward_okay, backward_okay, page_base;
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vm_pindex_t pindex = m->pindex;
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object = m->object;
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/*
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* If not OBJT_SWAP, additional memory may be needed to do the pageout.
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* Try to avoid the deadlock.
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*/
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if ((sync != VM_PAGEOUT_FORCE) &&
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(object->type == OBJT_DEFAULT) &&
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((cnt.v_free_count + cnt.v_cache_count) < cnt.v_pageout_free_min))
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return 0;
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/*
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* Don't mess with the page if it's busy.
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*/
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if ((!sync && m->hold_count != 0) ||
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((m->busy != 0) || (m->flags & PG_BUSY)))
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return 0;
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/*
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* Try collapsing before it's too late.
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*/
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if (!sync && object->backing_object) {
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vm_object_collapse(object);
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}
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mc[vm_pageout_page_count] = m;
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pageout_count = 1;
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page_base = vm_pageout_page_count;
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forward_okay = TRUE;
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if (pindex != 0)
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backward_okay = TRUE;
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else
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backward_okay = FALSE;
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/*
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* Scan object for clusterable pages.
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*
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* We can cluster ONLY if: ->> the page is NOT
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* clean, wired, busy, held, or mapped into a
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* buffer, and one of the following:
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* 1) The page is inactive, or a seldom used
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* active page.
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* -or-
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* 2) we force the issue.
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*/
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for (i = 1; (i < vm_pageout_page_count) && (forward_okay || backward_okay); i++) {
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vm_page_t p;
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/*
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* See if forward page is clusterable.
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*/
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if (forward_okay) {
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/*
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* Stop forward scan at end of object.
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*/
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if ((pindex + i) > object->size) {
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forward_okay = FALSE;
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goto do_backward;
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}
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p = vm_page_lookup(object, pindex + i);
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if (p) {
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if ((p->queue == PQ_CACHE) || (p->flags & PG_BUSY) || p->busy) {
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forward_okay = FALSE;
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goto do_backward;
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}
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vm_page_test_dirty(p);
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if ((p->dirty & p->valid) != 0 &&
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((p->queue == PQ_INACTIVE) ||
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(sync == VM_PAGEOUT_FORCE)) &&
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(p->wire_count == 0) &&
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(p->hold_count == 0)) {
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mc[vm_pageout_page_count + i] = p;
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pageout_count++;
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if (pageout_count == vm_pageout_page_count)
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break;
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} else {
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forward_okay = FALSE;
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}
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} else {
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forward_okay = FALSE;
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}
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}
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do_backward:
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/*
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* See if backward page is clusterable.
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*/
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if (backward_okay) {
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/*
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* Stop backward scan at beginning of object.
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*/
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if ((pindex - i) == 0) {
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backward_okay = FALSE;
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}
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p = vm_page_lookup(object, pindex - i);
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if (p) {
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if ((p->queue == PQ_CACHE) || (p->flags & PG_BUSY) || p->busy) {
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backward_okay = FALSE;
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continue;
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}
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vm_page_test_dirty(p);
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if ((p->dirty & p->valid) != 0 &&
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((p->queue == PQ_INACTIVE) ||
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(sync == VM_PAGEOUT_FORCE)) &&
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(p->wire_count == 0) &&
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(p->hold_count == 0)) {
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mc[vm_pageout_page_count - i] = p;
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pageout_count++;
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page_base--;
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if (pageout_count == vm_pageout_page_count)
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break;
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} else {
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backward_okay = FALSE;
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}
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} else {
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backward_okay = FALSE;
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}
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}
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}
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/*
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* we allow reads during pageouts...
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*/
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for (i = page_base; i < (page_base + pageout_count); i++) {
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mc[i]->flags |= PG_BUSY;
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vm_page_protect(mc[i], VM_PROT_READ);
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}
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return vm_pageout_flush(&mc[page_base], pageout_count, sync);
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}
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int
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vm_pageout_flush(mc, count, sync)
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vm_page_t *mc;
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int count;
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int sync;
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{
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register vm_object_t object;
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int pageout_status[count];
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int anyok = 0;
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int i;
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object = mc[0]->object;
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object->paging_in_progress += count;
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vm_pager_put_pages(object, mc, count,
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((sync || (object == kernel_object)) ? TRUE : FALSE),
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pageout_status);
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for (i = 0; i < count; i++) {
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vm_page_t mt = mc[i];
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switch (pageout_status[i]) {
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case VM_PAGER_OK:
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++anyok;
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break;
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case VM_PAGER_PEND:
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++anyok;
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break;
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case VM_PAGER_BAD:
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/*
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* Page outside of range of object. Right now we
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* essentially lose the changes by pretending it
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* worked.
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*/
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pmap_clear_modify(VM_PAGE_TO_PHYS(mt));
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mt->dirty = 0;
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break;
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case VM_PAGER_ERROR:
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case VM_PAGER_FAIL:
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/*
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* If page couldn't be paged out, then reactivate the
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* page so it doesn't clog the inactive list. (We
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* will try paging out it again later).
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*/
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if (mt->queue == PQ_INACTIVE)
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vm_page_activate(mt);
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break;
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case VM_PAGER_AGAIN:
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break;
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}
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/*
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* If the operation is still going, leave the page busy to
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* block all other accesses. Also, leave the paging in
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* progress indicator set so that we don't attempt an object
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* collapse.
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*/
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if (pageout_status[i] != VM_PAGER_PEND) {
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vm_object_pip_wakeup(object);
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PAGE_WAKEUP(mt);
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}
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}
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return anyok;
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}
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#if !defined(NO_SWAPPING)
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/*
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* vm_pageout_object_deactivate_pages
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*
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* deactivate enough pages to satisfy the inactive target
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* requirements or if vm_page_proc_limit is set, then
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* deactivate all of the pages in the object and its
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* backing_objects.
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*
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* The object and map must be locked.
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*/
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static void
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vm_pageout_object_deactivate_pages(map, object, desired, map_remove_only)
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vm_map_t map;
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vm_object_t object;
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vm_pindex_t desired;
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int map_remove_only;
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{
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register vm_page_t p, next;
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int rcount;
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int remove_mode;
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int s;
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if (object->type == OBJT_DEVICE)
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return;
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while (object) {
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if (vm_map_pmap(map)->pm_stats.resident_count <= desired)
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return;
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if (object->paging_in_progress)
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return;
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remove_mode = map_remove_only;
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if (object->shadow_count > 1)
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remove_mode = 1;
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/*
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* scan the objects entire memory queue
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*/
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rcount = object->resident_page_count;
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p = TAILQ_FIRST(&object->memq);
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while (p && (rcount-- > 0)) {
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int refcount;
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if (vm_map_pmap(map)->pm_stats.resident_count <= desired)
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return;
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next = TAILQ_NEXT(p, listq);
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cnt.v_pdpages++;
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if (p->wire_count != 0 ||
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p->hold_count != 0 ||
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p->busy != 0 ||
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(p->flags & PG_BUSY) ||
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!pmap_page_exists(vm_map_pmap(map), VM_PAGE_TO_PHYS(p))) {
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p = next;
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continue;
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}
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refcount = pmap_ts_referenced(VM_PAGE_TO_PHYS(p));
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if (refcount) {
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p->flags |= PG_REFERENCED;
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} else if (p->flags & PG_REFERENCED) {
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refcount = 1;
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}
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if ((p->queue != PQ_ACTIVE) &&
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(p->flags & PG_REFERENCED)) {
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vm_page_activate(p);
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p->act_count += refcount;
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p->flags &= ~PG_REFERENCED;
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} else if (p->queue == PQ_ACTIVE) {
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if ((p->flags & PG_REFERENCED) == 0) {
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p->act_count -= min(p->act_count, ACT_DECLINE);
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if (!remove_mode && (vm_pageout_algorithm_lru || (p->act_count == 0))) {
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vm_page_protect(p, VM_PROT_NONE);
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vm_page_deactivate(p);
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} else {
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s = splvm();
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TAILQ_REMOVE(&vm_page_queue_active, p, pageq);
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TAILQ_INSERT_TAIL(&vm_page_queue_active, p, pageq);
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splx(s);
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}
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} else {
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p->flags &= ~PG_REFERENCED;
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if (p->act_count < (ACT_MAX - ACT_ADVANCE))
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p->act_count += ACT_ADVANCE;
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s = splvm();
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TAILQ_REMOVE(&vm_page_queue_active, p, pageq);
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TAILQ_INSERT_TAIL(&vm_page_queue_active, p, pageq);
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splx(s);
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}
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} else if (p->queue == PQ_INACTIVE) {
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vm_page_protect(p, VM_PROT_NONE);
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}
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p = next;
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}
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object = object->backing_object;
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}
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return;
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}
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/*
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* deactivate some number of pages in a map, try to do it fairly, but
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* that is really hard to do.
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*/
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static void
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vm_pageout_map_deactivate_pages(map, desired)
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vm_map_t map;
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vm_pindex_t desired;
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{
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vm_map_entry_t tmpe;
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vm_object_t obj, bigobj;
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vm_map_reference(map);
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if (!lock_try_write(&map->lock)) {
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vm_map_deallocate(map);
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return;
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}
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bigobj = NULL;
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/*
|
|
* first, search out the biggest object, and try to free pages from
|
|
* that.
|
|
*/
|
|
tmpe = map->header.next;
|
|
while (tmpe != &map->header) {
|
|
if ((tmpe->is_sub_map == 0) && (tmpe->is_a_map == 0)) {
|
|
obj = tmpe->object.vm_object;
|
|
if ((obj != NULL) && (obj->shadow_count <= 1) &&
|
|
((bigobj == NULL) ||
|
|
(bigobj->resident_page_count < obj->resident_page_count))) {
|
|
bigobj = obj;
|
|
}
|
|
}
|
|
tmpe = tmpe->next;
|
|
}
|
|
|
|
if (bigobj)
|
|
vm_pageout_object_deactivate_pages(map, bigobj, desired, 0);
|
|
|
|
/*
|
|
* Next, hunt around for other pages to deactivate. We actually
|
|
* do this search sort of wrong -- .text first is not the best idea.
|
|
*/
|
|
tmpe = map->header.next;
|
|
while (tmpe != &map->header) {
|
|
if (vm_map_pmap(map)->pm_stats.resident_count <= desired)
|
|
break;
|
|
if ((tmpe->is_sub_map == 0) && (tmpe->is_a_map == 0)) {
|
|
obj = tmpe->object.vm_object;
|
|
if (obj)
|
|
vm_pageout_object_deactivate_pages(map, obj, desired, 0);
|
|
}
|
|
tmpe = tmpe->next;
|
|
};
|
|
|
|
/*
|
|
* Remove all mappings if a process is swapped out, this will free page
|
|
* table pages.
|
|
*/
|
|
if (desired == 0)
|
|
pmap_remove(vm_map_pmap(map),
|
|
VM_MIN_ADDRESS, VM_MAXUSER_ADDRESS);
|
|
vm_map_unlock(map);
|
|
vm_map_deallocate(map);
|
|
return;
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
* vm_pageout_scan does the dirty work for the pageout daemon.
|
|
*/
|
|
static int
|
|
vm_pageout_scan()
|
|
{
|
|
vm_page_t m, next;
|
|
int page_shortage, addl_page_shortage, maxscan, maxlaunder, pcount;
|
|
int pages_freed;
|
|
struct proc *p, *bigproc;
|
|
vm_offset_t size, bigsize;
|
|
vm_object_t object;
|
|
int force_wakeup = 0;
|
|
int vnodes_skipped = 0;
|
|
int s;
|
|
|
|
/*
|
|
* Start scanning the inactive queue for pages we can free. We keep
|
|
* scanning until we have enough free pages or we have scanned through
|
|
* the entire queue. If we encounter dirty pages, we start cleaning
|
|
* them.
|
|
*/
|
|
|
|
pages_freed = 0;
|
|
addl_page_shortage = 0;
|
|
|
|
maxlaunder = (cnt.v_inactive_target > MAXLAUNDER) ?
|
|
MAXLAUNDER : cnt.v_inactive_target;
|
|
rescan0:
|
|
maxscan = cnt.v_inactive_count;
|
|
for( m = TAILQ_FIRST(&vm_page_queue_inactive);
|
|
|
|
(m != NULL) && (maxscan-- > 0) &&
|
|
((cnt.v_cache_count + cnt.v_free_count) <
|
|
(cnt.v_cache_min + cnt.v_free_target));
|
|
|
|
m = next) {
|
|
|
|
cnt.v_pdpages++;
|
|
|
|
if (m->queue != PQ_INACTIVE) {
|
|
goto rescan0;
|
|
}
|
|
|
|
next = TAILQ_NEXT(m, pageq);
|
|
|
|
if (m->hold_count) {
|
|
s = splvm();
|
|
TAILQ_REMOVE(&vm_page_queue_inactive, m, pageq);
|
|
TAILQ_INSERT_TAIL(&vm_page_queue_inactive, m, pageq);
|
|
splx(s);
|
|
addl_page_shortage++;
|
|
continue;
|
|
}
|
|
/*
|
|
* Dont mess with busy pages, keep in the front of the
|
|
* queue, most likely are being paged out.
|
|
*/
|
|
if (m->busy || (m->flags & PG_BUSY)) {
|
|
addl_page_shortage++;
|
|
continue;
|
|
}
|
|
|
|
if (m->object->ref_count == 0) {
|
|
m->flags &= ~PG_REFERENCED;
|
|
pmap_clear_reference(VM_PAGE_TO_PHYS(m));
|
|
} else if (((m->flags & PG_REFERENCED) == 0) &&
|
|
pmap_ts_referenced(VM_PAGE_TO_PHYS(m))) {
|
|
vm_page_activate(m);
|
|
continue;
|
|
}
|
|
|
|
if ((m->flags & PG_REFERENCED) != 0) {
|
|
m->flags &= ~PG_REFERENCED;
|
|
pmap_clear_reference(VM_PAGE_TO_PHYS(m));
|
|
vm_page_activate(m);
|
|
continue;
|
|
}
|
|
|
|
if (m->dirty == 0) {
|
|
vm_page_test_dirty(m);
|
|
} else if (m->dirty != 0) {
|
|
m->dirty = VM_PAGE_BITS_ALL;
|
|
}
|
|
|
|
if (m->valid == 0) {
|
|
vm_page_protect(m, VM_PROT_NONE);
|
|
vm_page_free(m);
|
|
cnt.v_dfree++;
|
|
++pages_freed;
|
|
} else if (m->dirty == 0) {
|
|
vm_page_cache(m);
|
|
++pages_freed;
|
|
} else if (maxlaunder > 0) {
|
|
int written;
|
|
struct vnode *vp = NULL;
|
|
|
|
object = m->object;
|
|
if (object->flags & OBJ_DEAD) {
|
|
s = splvm();
|
|
TAILQ_REMOVE(&vm_page_queue_inactive, m, pageq);
|
|
TAILQ_INSERT_TAIL(&vm_page_queue_inactive, m, pageq);
|
|
splx(s);
|
|
continue;
|
|
}
|
|
|
|
if (object->type == OBJT_VNODE) {
|
|
vp = object->handle;
|
|
if (VOP_ISLOCKED(vp) || vget(vp, 1)) {
|
|
if ((m->queue == PQ_INACTIVE) &&
|
|
(m->hold_count == 0) &&
|
|
(m->busy == 0) &&
|
|
(m->flags & PG_BUSY) == 0) {
|
|
s = splvm();
|
|
TAILQ_REMOVE(&vm_page_queue_inactive, m, pageq);
|
|
TAILQ_INSERT_TAIL(&vm_page_queue_inactive, m, pageq);
|
|
splx(s);
|
|
}
|
|
if (object->flags & OBJ_MIGHTBEDIRTY)
|
|
++vnodes_skipped;
|
|
continue;
|
|
}
|
|
|
|
/*
|
|
* The page might have been moved to another queue
|
|
* during potential blocking in vget() above.
|
|
*/
|
|
if (m->queue != PQ_INACTIVE) {
|
|
if (object->flags & OBJ_MIGHTBEDIRTY)
|
|
++vnodes_skipped;
|
|
vput(vp);
|
|
continue;
|
|
}
|
|
|
|
/*
|
|
* The page may have been busied during the blocking in
|
|
* vput(); We don't move the page back onto the end of
|
|
* the queue so that statistics are more correct if we don't.
|
|
*/
|
|
if (m->busy || (m->flags & PG_BUSY)) {
|
|
vput(vp);
|
|
continue;
|
|
}
|
|
|
|
/*
|
|
* If the page has become held, then skip it
|
|
*/
|
|
if (m->hold_count) {
|
|
s = splvm();
|
|
TAILQ_REMOVE(&vm_page_queue_inactive, m, pageq);
|
|
TAILQ_INSERT_TAIL(&vm_page_queue_inactive, m, pageq);
|
|
splx(s);
|
|
if (object->flags & OBJ_MIGHTBEDIRTY)
|
|
++vnodes_skipped;
|
|
vput(vp);
|
|
continue;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* If a page is dirty, then it is either being washed
|
|
* (but not yet cleaned) or it is still in the
|
|
* laundry. If it is still in the laundry, then we
|
|
* start the cleaning operation.
|
|
*/
|
|
written = vm_pageout_clean(m, 0);
|
|
|
|
if (vp)
|
|
vput(vp);
|
|
|
|
maxlaunder -= written;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Compute the page shortage. If we are still very low on memory be
|
|
* sure that we will move a minimal amount of pages from active to
|
|
* inactive.
|
|
*/
|
|
|
|
page_shortage = (cnt.v_inactive_target + cnt.v_cache_min) -
|
|
(cnt.v_free_count + cnt.v_inactive_count + cnt.v_cache_count);
|
|
if (page_shortage <= 0) {
|
|
if (pages_freed == 0) {
|
|
page_shortage = cnt.v_free_min - cnt.v_free_count;
|
|
} else {
|
|
page_shortage = 1;
|
|
}
|
|
}
|
|
if (addl_page_shortage) {
|
|
if (page_shortage < 0)
|
|
page_shortage = 0;
|
|
page_shortage += addl_page_shortage;
|
|
}
|
|
|
|
pcount = cnt.v_active_count;
|
|
m = TAILQ_FIRST(&vm_page_queue_active);
|
|
while ((m != NULL) && (pcount-- > 0) && (page_shortage > 0)) {
|
|
int refcount;
|
|
|
|
if (m->queue != PQ_ACTIVE) {
|
|
break;
|
|
}
|
|
|
|
next = TAILQ_NEXT(m, pageq);
|
|
/*
|
|
* Don't deactivate pages that are busy.
|
|
*/
|
|
if ((m->busy != 0) ||
|
|
(m->flags & PG_BUSY) ||
|
|
(m->hold_count != 0)) {
|
|
s = splvm();
|
|
TAILQ_REMOVE(&vm_page_queue_active, m, pageq);
|
|
TAILQ_INSERT_TAIL(&vm_page_queue_active, m, pageq);
|
|
splx(s);
|
|
m = next;
|
|
continue;
|
|
}
|
|
|
|
/*
|
|
* The count for pagedaemon pages is done after checking the
|
|
* page for eligbility...
|
|
*/
|
|
cnt.v_pdpages++;
|
|
|
|
refcount = 0;
|
|
if (m->object->ref_count != 0) {
|
|
if (m->flags & PG_REFERENCED) {
|
|
refcount += 1;
|
|
}
|
|
refcount += pmap_ts_referenced(VM_PAGE_TO_PHYS(m));
|
|
if (refcount) {
|
|
m->act_count += ACT_ADVANCE + refcount;
|
|
if (m->act_count > ACT_MAX)
|
|
m->act_count = ACT_MAX;
|
|
}
|
|
}
|
|
|
|
m->flags &= ~PG_REFERENCED;
|
|
|
|
if (refcount && (m->object->ref_count != 0)) {
|
|
s = splvm();
|
|
TAILQ_REMOVE(&vm_page_queue_active, m, pageq);
|
|
TAILQ_INSERT_TAIL(&vm_page_queue_active, m, pageq);
|
|
splx(s);
|
|
} else {
|
|
m->act_count -= min(m->act_count, ACT_DECLINE);
|
|
if (vm_pageout_algorithm_lru ||
|
|
(m->object->ref_count == 0) || (m->act_count == 0)) {
|
|
--page_shortage;
|
|
vm_page_protect(m, VM_PROT_NONE);
|
|
if ((m->dirty == 0) &&
|
|
(m->object->ref_count == 0)) {
|
|
vm_page_cache(m);
|
|
} else {
|
|
vm_page_deactivate(m);
|
|
}
|
|
} else {
|
|
s = splvm();
|
|
TAILQ_REMOVE(&vm_page_queue_active, m, pageq);
|
|
TAILQ_INSERT_TAIL(&vm_page_queue_active, m, pageq);
|
|
splx(s);
|
|
}
|
|
}
|
|
m = next;
|
|
}
|
|
|
|
s = splvm();
|
|
/*
|
|
* We try to maintain some *really* free pages, this allows interrupt
|
|
* code to be guaranteed space.
|
|
*/
|
|
while (cnt.v_free_count < cnt.v_free_reserved) {
|
|
m = TAILQ_FIRST(&vm_page_queue_cache);
|
|
if (!m)
|
|
break;
|
|
vm_page_free(m);
|
|
cnt.v_dfree++;
|
|
}
|
|
splx(s);
|
|
|
|
/*
|
|
* If we didn't get enough free pages, and we have skipped a vnode
|
|
* in a writeable object, wakeup the sync daemon. And kick swapout
|
|
* if we did not get enough free pages.
|
|
*/
|
|
if ((cnt.v_cache_count + cnt.v_free_count) <
|
|
(cnt.v_free_target + cnt.v_cache_min) ) {
|
|
if (vnodes_skipped &&
|
|
(cnt.v_cache_count + cnt.v_free_count) < cnt.v_free_min) {
|
|
if (!vfs_update_wakeup) {
|
|
vfs_update_wakeup = 1;
|
|
wakeup(&vfs_update_wakeup);
|
|
}
|
|
}
|
|
#if !defined(NO_SWAPPING)
|
|
if (vm_swapping_enabled &&
|
|
(cnt.v_free_count + cnt.v_cache_count < cnt.v_free_target)) {
|
|
vm_req_vmdaemon();
|
|
vm_pageout_req_swapout = 1;
|
|
}
|
|
#endif
|
|
}
|
|
|
|
|
|
/*
|
|
* make sure that we have swap space -- if we are low on memory and
|
|
* swap -- then kill the biggest process.
|
|
*/
|
|
if ((vm_swap_size == 0 || swap_pager_full) &&
|
|
((cnt.v_free_count + cnt.v_cache_count) < cnt.v_free_min)) {
|
|
bigproc = NULL;
|
|
bigsize = 0;
|
|
for (p = allproc.lh_first; p != 0; p = p->p_list.le_next) {
|
|
/*
|
|
* if this is a system process, skip it
|
|
*/
|
|
if ((p->p_flag & P_SYSTEM) || (p->p_pid == 1) ||
|
|
((p->p_pid < 48) && (vm_swap_size != 0))) {
|
|
continue;
|
|
}
|
|
/*
|
|
* if the process is in a non-running type state,
|
|
* don't touch it.
|
|
*/
|
|
if (p->p_stat != SRUN && p->p_stat != SSLEEP) {
|
|
continue;
|
|
}
|
|
/*
|
|
* get the process size
|
|
*/
|
|
size = p->p_vmspace->vm_pmap.pm_stats.resident_count;
|
|
/*
|
|
* if the this process is bigger than the biggest one
|
|
* remember it.
|
|
*/
|
|
if (size > bigsize) {
|
|
bigproc = p;
|
|
bigsize = size;
|
|
}
|
|
}
|
|
if (bigproc != NULL) {
|
|
killproc(bigproc, "out of swap space");
|
|
bigproc->p_estcpu = 0;
|
|
bigproc->p_nice = PRIO_MIN;
|
|
resetpriority(bigproc);
|
|
wakeup(&cnt.v_free_count);
|
|
}
|
|
}
|
|
return force_wakeup;
|
|
}
|
|
|
|
static int
|
|
vm_pageout_free_page_calc(count)
|
|
vm_size_t count;
|
|
{
|
|
if (count < cnt.v_page_count)
|
|
return 0;
|
|
/*
|
|
* free_reserved needs to include enough for the largest swap pager
|
|
* structures plus enough for any pv_entry structs when paging.
|
|
*/
|
|
if (cnt.v_page_count > 1024)
|
|
cnt.v_free_min = 4 + (cnt.v_page_count - 1024) / 200;
|
|
else
|
|
cnt.v_free_min = 4;
|
|
cnt.v_pageout_free_min = (2*MAXBSIZE)/PAGE_SIZE +
|
|
cnt.v_interrupt_free_min;
|
|
cnt.v_free_reserved = vm_pageout_page_count +
|
|
cnt.v_pageout_free_min + (count / 768);
|
|
cnt.v_free_min += cnt.v_free_reserved;
|
|
return 1;
|
|
}
|
|
|
|
|
|
#ifdef unused
|
|
int
|
|
vm_pageout_free_pages(object, add)
|
|
vm_object_t object;
|
|
int add;
|
|
{
|
|
return vm_pageout_free_page_calc(object->size);
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
* vm_pageout is the high level pageout daemon.
|
|
*/
|
|
static void
|
|
vm_pageout()
|
|
{
|
|
(void) spl0();
|
|
|
|
/*
|
|
* Initialize some paging parameters.
|
|
*/
|
|
|
|
cnt.v_interrupt_free_min = 2;
|
|
if (cnt.v_page_count < 2000)
|
|
vm_pageout_page_count = 8;
|
|
|
|
vm_pageout_free_page_calc(cnt.v_page_count);
|
|
/*
|
|
* free_reserved needs to include enough for the largest swap pager
|
|
* structures plus enough for any pv_entry structs when paging.
|
|
*/
|
|
cnt.v_free_target = 3 * cnt.v_free_min + cnt.v_free_reserved;
|
|
|
|
if (cnt.v_free_count > 1024) {
|
|
cnt.v_cache_max = (cnt.v_free_count - 1024) / 2;
|
|
cnt.v_cache_min = (cnt.v_free_count - 1024) / 8;
|
|
cnt.v_inactive_target = 2*cnt.v_cache_min + 192;
|
|
} else {
|
|
cnt.v_cache_min = 0;
|
|
cnt.v_cache_max = 0;
|
|
cnt.v_inactive_target = cnt.v_free_count / 4;
|
|
}
|
|
|
|
/* XXX does not really belong here */
|
|
if (vm_page_max_wired == 0)
|
|
vm_page_max_wired = cnt.v_free_count / 3;
|
|
|
|
|
|
swap_pager_swap_init();
|
|
/*
|
|
* The pageout daemon is never done, so loop forever.
|
|
*/
|
|
while (TRUE) {
|
|
int inactive_target;
|
|
int s = splvm();
|
|
if (!vm_pages_needed ||
|
|
((cnt.v_free_count + cnt.v_cache_count) > cnt.v_free_min)) {
|
|
vm_pages_needed = 0;
|
|
tsleep(&vm_pages_needed, PVM, "psleep", 0);
|
|
} else if (!vm_pages_needed) {
|
|
tsleep(&vm_pages_needed, PVM, "psleep", hz/10);
|
|
}
|
|
inactive_target =
|
|
(cnt.v_page_count - cnt.v_wire_count) / 4;
|
|
if (inactive_target < 2*cnt.v_free_min)
|
|
inactive_target = 2*cnt.v_free_min;
|
|
cnt.v_inactive_target = inactive_target;
|
|
if (vm_pages_needed)
|
|
cnt.v_pdwakeups++;
|
|
vm_pages_needed = 0;
|
|
splx(s);
|
|
vm_pager_sync();
|
|
vm_pageout_scan();
|
|
vm_pager_sync();
|
|
wakeup(&cnt.v_free_count);
|
|
}
|
|
}
|
|
|
|
#if !defined(NO_SWAPPING)
|
|
static void
|
|
vm_req_vmdaemon()
|
|
{
|
|
static int lastrun = 0;
|
|
|
|
if ((ticks > (lastrun + hz)) || (ticks < lastrun)) {
|
|
wakeup(&vm_daemon_needed);
|
|
lastrun = ticks;
|
|
}
|
|
}
|
|
|
|
static void
|
|
vm_daemon()
|
|
{
|
|
vm_object_t object;
|
|
struct proc *p;
|
|
|
|
(void) spl0();
|
|
|
|
while (TRUE) {
|
|
tsleep(&vm_daemon_needed, PUSER, "psleep", 0);
|
|
if (vm_pageout_req_swapout) {
|
|
swapout_procs();
|
|
vm_pageout_req_swapout = 0;
|
|
}
|
|
/*
|
|
* scan the processes for exceeding their rlimits or if
|
|
* process is swapped out -- deactivate pages
|
|
*/
|
|
|
|
for (p = allproc.lh_first; p != 0; p = p->p_list.le_next) {
|
|
quad_t limit;
|
|
vm_offset_t size;
|
|
|
|
/*
|
|
* if this is a system process or if we have already
|
|
* looked at this process, skip it.
|
|
*/
|
|
if (p->p_flag & (P_SYSTEM | P_WEXIT)) {
|
|
continue;
|
|
}
|
|
/*
|
|
* if the process is in a non-running type state,
|
|
* don't touch it.
|
|
*/
|
|
if (p->p_stat != SRUN && p->p_stat != SSLEEP) {
|
|
continue;
|
|
}
|
|
/*
|
|
* get a limit
|
|
*/
|
|
limit = qmin(p->p_rlimit[RLIMIT_RSS].rlim_cur,
|
|
p->p_rlimit[RLIMIT_RSS].rlim_max);
|
|
|
|
/*
|
|
* let processes that are swapped out really be
|
|
* swapped out set the limit to nothing (will force a
|
|
* swap-out.)
|
|
*/
|
|
if ((p->p_flag & P_INMEM) == 0)
|
|
limit = 0; /* XXX */
|
|
|
|
size = p->p_vmspace->vm_pmap.pm_stats.resident_count * PAGE_SIZE;
|
|
if (limit >= 0 && size >= limit) {
|
|
vm_pageout_map_deactivate_pages(&p->p_vmspace->vm_map,
|
|
(vm_pindex_t)(limit >> PAGE_SHIFT) );
|
|
}
|
|
}
|
|
|
|
/*
|
|
* we remove cached objects that have no RSS...
|
|
*/
|
|
restart:
|
|
object = TAILQ_FIRST(&vm_object_cached_list);
|
|
while (object) {
|
|
/*
|
|
* if there are no resident pages -- get rid of the object
|
|
*/
|
|
if (object->resident_page_count == 0) {
|
|
vm_object_reference(object);
|
|
pager_cache(object, FALSE);
|
|
goto restart;
|
|
}
|
|
object = TAILQ_NEXT(object, cached_list);
|
|
}
|
|
}
|
|
}
|
|
#endif
|