978 lines
24 KiB
C
978 lines
24 KiB
C
/*-
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* SPDX-License-Identifier: (BSD-4-Clause AND MIT-CMU)
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*
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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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* Copyright (c) 2005 Yahoo! Technologies Norway AS
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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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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include "opt_kstack_pages.h"
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#include "opt_kstack_max_pages.h"
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#include "opt_vm.h"
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/limits.h>
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#include <sys/kernel.h>
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#include <sys/eventhandler.h>
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#include <sys/lock.h>
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#include <sys/mutex.h>
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#include <sys/proc.h>
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#include <sys/_kstack_cache.h>
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#include <sys/kthread.h>
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#include <sys/ktr.h>
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#include <sys/mount.h>
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#include <sys/racct.h>
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#include <sys/resourcevar.h>
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#include <sys/sched.h>
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#include <sys/sdt.h>
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#include <sys/signalvar.h>
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#include <sys/smp.h>
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#include <sys/time.h>
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#include <sys/vnode.h>
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#include <sys/vmmeter.h>
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#include <sys/rwlock.h>
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#include <sys/sx.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_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_pager.h>
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#include <vm/vm_phys.h>
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#include <vm/swap_pager.h>
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#include <vm/vm_extern.h>
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#include <vm/uma.h>
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/* the kernel process "vm_daemon" */
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static void vm_daemon(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(vmdaemon, SI_SUB_KTHREAD_VM, SI_ORDER_FIRST, kproc_start, &vm_kp);
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static int vm_swap_enabled = 1;
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static int vm_swap_idle_enabled = 0;
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SYSCTL_INT(_vm, VM_SWAPPING_ENABLED, swap_enabled, CTLFLAG_RW,
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&vm_swap_enabled, 0,
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"Enable entire process swapout");
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SYSCTL_INT(_vm, OID_AUTO, swap_idle_enabled, CTLFLAG_RW,
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&vm_swap_idle_enabled, 0,
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"Allow swapout on idle criteria");
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/*
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* Swap_idle_threshold1 is the guaranteed swapped in time for a process
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*/
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static int swap_idle_threshold1 = 2;
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SYSCTL_INT(_vm, OID_AUTO, swap_idle_threshold1, CTLFLAG_RW,
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&swap_idle_threshold1, 0,
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"Guaranteed swapped in time for a process");
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/*
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* Swap_idle_threshold2 is the time that a process can be idle before
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* it will be swapped out, if idle swapping is enabled.
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*/
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static int swap_idle_threshold2 = 10;
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SYSCTL_INT(_vm, OID_AUTO, swap_idle_threshold2, CTLFLAG_RW,
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&swap_idle_threshold2, 0,
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"Time before a process will be swapped out");
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static int vm_pageout_req_swapout; /* XXX */
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static int vm_daemon_needed;
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static struct mtx vm_daemon_mtx;
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/* Allow for use by vm_pageout before vm_daemon is initialized. */
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MTX_SYSINIT(vm_daemon, &vm_daemon_mtx, "vm daemon", MTX_DEF);
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static void swapclear(struct proc *);
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static int swapout(struct proc *);
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static void vm_swapout_map_deactivate_pages(vm_map_t, long);
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static void vm_swapout_object_deactivate_pages(pmap_t, vm_object_t, long);
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static void swapout_procs(int action);
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static void vm_req_vmdaemon(int req);
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static void vm_thread_swapin(struct thread *td);
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static void vm_thread_swapout(struct thread *td);
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/*
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* vm_swapout_object_deactivate_pages
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*
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* Deactivate enough pages to satisfy the inactive target
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* requirements.
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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_swapout_object_deactivate_pages(pmap_t pmap, vm_object_t first_object,
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long desired)
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{
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vm_object_t backing_object, object;
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vm_page_t p;
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int act_delta, remove_mode;
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VM_OBJECT_ASSERT_LOCKED(first_object);
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if ((first_object->flags & OBJ_FICTITIOUS) != 0)
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return;
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for (object = first_object;; object = backing_object) {
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if (pmap_resident_count(pmap) <= desired)
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goto unlock_return;
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VM_OBJECT_ASSERT_LOCKED(object);
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if ((object->flags & OBJ_UNMANAGED) != 0 ||
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object->paging_in_progress != 0)
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goto unlock_return;
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remove_mode = 0;
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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 object's entire memory queue.
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*/
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TAILQ_FOREACH(p, &object->memq, listq) {
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if (pmap_resident_count(pmap) <= desired)
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goto unlock_return;
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if (vm_page_busied(p))
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continue;
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VM_CNT_INC(v_pdpages);
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vm_page_lock(p);
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if (p->wire_count != 0 || p->hold_count != 0 ||
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!pmap_page_exists_quick(pmap, p)) {
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vm_page_unlock(p);
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continue;
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}
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act_delta = pmap_ts_referenced(p);
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if ((p->aflags & PGA_REFERENCED) != 0) {
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if (act_delta == 0)
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act_delta = 1;
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vm_page_aflag_clear(p, PGA_REFERENCED);
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}
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if (!vm_page_active(p) && act_delta != 0) {
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vm_page_activate(p);
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p->act_count += act_delta;
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} else if (vm_page_active(p)) {
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if (act_delta == 0) {
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p->act_count -= min(p->act_count,
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ACT_DECLINE);
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if (!remove_mode && p->act_count == 0) {
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pmap_remove_all(p);
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vm_page_deactivate(p);
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} else
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vm_page_requeue(p);
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} else {
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vm_page_activate(p);
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if (p->act_count < ACT_MAX -
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ACT_ADVANCE)
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p->act_count += ACT_ADVANCE;
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vm_page_requeue(p);
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}
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} else if (vm_page_inactive(p))
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pmap_remove_all(p);
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vm_page_unlock(p);
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}
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if ((backing_object = object->backing_object) == NULL)
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goto unlock_return;
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VM_OBJECT_RLOCK(backing_object);
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if (object != first_object)
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VM_OBJECT_RUNLOCK(object);
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}
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unlock_return:
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if (object != first_object)
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VM_OBJECT_RUNLOCK(object);
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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_swapout_map_deactivate_pages(vm_map_t map, long 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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int nothingwired;
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if (!vm_map_trylock(map))
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return;
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bigobj = NULL;
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nothingwired = TRUE;
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/*
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* first, search out the biggest object, and try to free pages from
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* that.
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*/
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tmpe = map->header.next;
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while (tmpe != &map->header) {
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if ((tmpe->eflags & MAP_ENTRY_IS_SUB_MAP) == 0) {
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obj = tmpe->object.vm_object;
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if (obj != NULL && VM_OBJECT_TRYRLOCK(obj)) {
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if (obj->shadow_count <= 1 &&
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(bigobj == NULL ||
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bigobj->resident_page_count <
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obj->resident_page_count)) {
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if (bigobj != NULL)
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VM_OBJECT_RUNLOCK(bigobj);
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bigobj = obj;
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} else
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VM_OBJECT_RUNLOCK(obj);
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}
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}
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if (tmpe->wired_count > 0)
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nothingwired = FALSE;
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tmpe = tmpe->next;
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}
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if (bigobj != NULL) {
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vm_swapout_object_deactivate_pages(map->pmap, bigobj, desired);
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VM_OBJECT_RUNLOCK(bigobj);
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}
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/*
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* Next, hunt around for other pages to deactivate. We actually
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* do this search sort of wrong -- .text first is not the best idea.
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*/
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tmpe = map->header.next;
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while (tmpe != &map->header) {
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if (pmap_resident_count(vm_map_pmap(map)) <= desired)
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break;
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if ((tmpe->eflags & MAP_ENTRY_IS_SUB_MAP) == 0) {
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obj = tmpe->object.vm_object;
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if (obj != NULL) {
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VM_OBJECT_RLOCK(obj);
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vm_swapout_object_deactivate_pages(map->pmap,
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obj, desired);
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VM_OBJECT_RUNLOCK(obj);
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}
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}
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tmpe = tmpe->next;
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}
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/*
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* Remove all mappings if a process is swapped out, this will free page
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* table pages.
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*/
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if (desired == 0 && nothingwired) {
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pmap_remove(vm_map_pmap(map), vm_map_min(map),
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vm_map_max(map));
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}
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vm_map_unlock(map);
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}
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/*
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* Swap out requests
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*/
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#define VM_SWAP_NORMAL 1
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#define VM_SWAP_IDLE 2
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void
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vm_swapout_run(void)
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{
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if (vm_swap_enabled)
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vm_req_vmdaemon(VM_SWAP_NORMAL);
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}
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/*
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* Idle process swapout -- run once per second when pagedaemons are
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* reclaiming pages.
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*/
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void
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vm_swapout_run_idle(void)
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{
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static long lsec;
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if (!vm_swap_idle_enabled || time_second == lsec)
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return;
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vm_req_vmdaemon(VM_SWAP_IDLE);
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lsec = time_second;
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}
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static void
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vm_req_vmdaemon(int req)
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{
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static int lastrun = 0;
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mtx_lock(&vm_daemon_mtx);
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vm_pageout_req_swapout |= req;
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if ((ticks > (lastrun + hz)) || (ticks < lastrun)) {
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wakeup(&vm_daemon_needed);
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lastrun = ticks;
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}
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mtx_unlock(&vm_daemon_mtx);
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}
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static void
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vm_daemon(void)
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{
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struct rlimit rsslim;
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struct proc *p;
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struct thread *td;
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struct vmspace *vm;
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int breakout, swapout_flags, tryagain, attempts;
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#ifdef RACCT
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uint64_t rsize, ravailable;
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#endif
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while (TRUE) {
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mtx_lock(&vm_daemon_mtx);
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msleep(&vm_daemon_needed, &vm_daemon_mtx, PPAUSE, "psleep",
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#ifdef RACCT
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racct_enable ? hz : 0
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#else
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0
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#endif
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);
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swapout_flags = vm_pageout_req_swapout;
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vm_pageout_req_swapout = 0;
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mtx_unlock(&vm_daemon_mtx);
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if (swapout_flags)
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swapout_procs(swapout_flags);
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/*
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* scan the processes for exceeding their rlimits or if
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* process is swapped out -- deactivate pages
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*/
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tryagain = 0;
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attempts = 0;
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again:
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attempts++;
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sx_slock(&allproc_lock);
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FOREACH_PROC_IN_SYSTEM(p) {
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vm_pindex_t limit, size;
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/*
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* if this is a system process or if we have already
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* looked at this process, skip it.
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*/
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PROC_LOCK(p);
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if (p->p_state != PRS_NORMAL ||
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p->p_flag & (P_INEXEC | P_SYSTEM | P_WEXIT)) {
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PROC_UNLOCK(p);
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continue;
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}
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/*
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* if the process is in a non-running type state,
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* don't touch it.
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*/
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breakout = 0;
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FOREACH_THREAD_IN_PROC(p, td) {
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thread_lock(td);
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if (!TD_ON_RUNQ(td) &&
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!TD_IS_RUNNING(td) &&
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!TD_IS_SLEEPING(td) &&
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!TD_IS_SUSPENDED(td)) {
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thread_unlock(td);
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breakout = 1;
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break;
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}
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thread_unlock(td);
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}
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if (breakout) {
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PROC_UNLOCK(p);
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continue;
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}
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/*
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* get a limit
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*/
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lim_rlimit_proc(p, RLIMIT_RSS, &rsslim);
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limit = OFF_TO_IDX(
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qmin(rsslim.rlim_cur, rsslim.rlim_max));
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/*
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* let processes that are swapped out really be
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* swapped out set the limit to nothing (will force a
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* swap-out.)
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*/
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if ((p->p_flag & P_INMEM) == 0)
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limit = 0; /* XXX */
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vm = vmspace_acquire_ref(p);
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_PHOLD_LITE(p);
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PROC_UNLOCK(p);
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if (vm == NULL) {
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PRELE(p);
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continue;
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}
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sx_sunlock(&allproc_lock);
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size = vmspace_resident_count(vm);
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if (size >= limit) {
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vm_swapout_map_deactivate_pages(
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&vm->vm_map, limit);
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size = vmspace_resident_count(vm);
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}
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#ifdef RACCT
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if (racct_enable) {
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rsize = IDX_TO_OFF(size);
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PROC_LOCK(p);
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if (p->p_state == PRS_NORMAL)
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racct_set(p, RACCT_RSS, rsize);
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ravailable = racct_get_available(p, RACCT_RSS);
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PROC_UNLOCK(p);
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if (rsize > ravailable) {
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/*
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* Don't be overly aggressive; this
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* might be an innocent process,
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* and the limit could've been exceeded
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* by some memory hog. Don't try
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* to deactivate more than 1/4th
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* of process' resident set size.
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*/
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if (attempts <= 8) {
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if (ravailable < rsize -
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(rsize / 4)) {
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ravailable = rsize -
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(rsize / 4);
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}
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}
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vm_swapout_map_deactivate_pages(
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&vm->vm_map,
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OFF_TO_IDX(ravailable));
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/* Update RSS usage after paging out. */
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size = vmspace_resident_count(vm);
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rsize = IDX_TO_OFF(size);
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PROC_LOCK(p);
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if (p->p_state == PRS_NORMAL)
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racct_set(p, RACCT_RSS, rsize);
|
|
PROC_UNLOCK(p);
|
|
if (rsize > ravailable)
|
|
tryagain = 1;
|
|
}
|
|
}
|
|
#endif
|
|
vmspace_free(vm);
|
|
sx_slock(&allproc_lock);
|
|
PRELE(p);
|
|
}
|
|
sx_sunlock(&allproc_lock);
|
|
if (tryagain != 0 && attempts <= 10)
|
|
goto again;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Allow a thread's kernel stack to be paged out.
|
|
*/
|
|
static void
|
|
vm_thread_swapout(struct thread *td)
|
|
{
|
|
vm_object_t ksobj;
|
|
vm_page_t m;
|
|
int i, pages;
|
|
|
|
cpu_thread_swapout(td);
|
|
pages = td->td_kstack_pages;
|
|
ksobj = td->td_kstack_obj;
|
|
pmap_qremove(td->td_kstack, pages);
|
|
VM_OBJECT_WLOCK(ksobj);
|
|
for (i = 0; i < pages; i++) {
|
|
m = vm_page_lookup(ksobj, i);
|
|
if (m == NULL)
|
|
panic("vm_thread_swapout: kstack already missing?");
|
|
vm_page_dirty(m);
|
|
vm_page_lock(m);
|
|
vm_page_unwire(m, PQ_INACTIVE);
|
|
vm_page_unlock(m);
|
|
}
|
|
VM_OBJECT_WUNLOCK(ksobj);
|
|
}
|
|
|
|
/*
|
|
* Bring the kernel stack for a specified thread back in.
|
|
*/
|
|
static void
|
|
vm_thread_swapin(struct thread *td)
|
|
{
|
|
vm_object_t ksobj;
|
|
vm_page_t ma[KSTACK_MAX_PAGES];
|
|
int pages;
|
|
|
|
pages = td->td_kstack_pages;
|
|
ksobj = td->td_kstack_obj;
|
|
VM_OBJECT_WLOCK(ksobj);
|
|
(void)vm_page_grab_pages(ksobj, 0, VM_ALLOC_NORMAL | VM_ALLOC_WIRED, ma,
|
|
pages);
|
|
for (int i = 0; i < pages;) {
|
|
int j, a, count, rv;
|
|
|
|
vm_page_assert_xbusied(ma[i]);
|
|
if (ma[i]->valid == VM_PAGE_BITS_ALL) {
|
|
vm_page_xunbusy(ma[i]);
|
|
i++;
|
|
continue;
|
|
}
|
|
vm_object_pip_add(ksobj, 1);
|
|
for (j = i + 1; j < pages; j++)
|
|
if (ma[j]->valid == VM_PAGE_BITS_ALL)
|
|
break;
|
|
rv = vm_pager_has_page(ksobj, ma[i]->pindex, NULL, &a);
|
|
KASSERT(rv == 1, ("%s: missing page %p", __func__, ma[i]));
|
|
count = min(a + 1, j - i);
|
|
rv = vm_pager_get_pages(ksobj, ma + i, count, NULL, NULL);
|
|
KASSERT(rv == VM_PAGER_OK, ("%s: cannot get kstack for proc %d",
|
|
__func__, td->td_proc->p_pid));
|
|
vm_object_pip_wakeup(ksobj);
|
|
for (j = i; j < i + count; j++)
|
|
vm_page_xunbusy(ma[j]);
|
|
i += count;
|
|
}
|
|
VM_OBJECT_WUNLOCK(ksobj);
|
|
pmap_qenter(td->td_kstack, ma, pages);
|
|
cpu_thread_swapin(td);
|
|
}
|
|
|
|
void
|
|
faultin(struct proc *p)
|
|
{
|
|
struct thread *td;
|
|
|
|
PROC_LOCK_ASSERT(p, MA_OWNED);
|
|
/*
|
|
* If another process is swapping in this process,
|
|
* just wait until it finishes.
|
|
*/
|
|
if (p->p_flag & P_SWAPPINGIN) {
|
|
while (p->p_flag & P_SWAPPINGIN)
|
|
msleep(&p->p_flag, &p->p_mtx, PVM, "faultin", 0);
|
|
return;
|
|
}
|
|
if ((p->p_flag & P_INMEM) == 0) {
|
|
/*
|
|
* Don't let another thread swap process p out while we are
|
|
* busy swapping it in.
|
|
*/
|
|
++p->p_lock;
|
|
p->p_flag |= P_SWAPPINGIN;
|
|
PROC_UNLOCK(p);
|
|
|
|
/*
|
|
* We hold no lock here because the list of threads
|
|
* can not change while all threads in the process are
|
|
* swapped out.
|
|
*/
|
|
FOREACH_THREAD_IN_PROC(p, td)
|
|
vm_thread_swapin(td);
|
|
PROC_LOCK(p);
|
|
swapclear(p);
|
|
p->p_swtick = ticks;
|
|
|
|
wakeup(&p->p_flag);
|
|
|
|
/* Allow other threads to swap p out now. */
|
|
--p->p_lock;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* This swapin algorithm attempts to swap-in processes only if there
|
|
* is enough space for them. Of course, if a process waits for a long
|
|
* time, it will be swapped in anyway.
|
|
*/
|
|
void
|
|
swapper(void)
|
|
{
|
|
struct proc *p;
|
|
struct thread *td;
|
|
struct proc *pp;
|
|
int slptime;
|
|
int swtime;
|
|
int ppri;
|
|
int pri;
|
|
|
|
loop:
|
|
if (vm_page_count_min()) {
|
|
VM_WAIT;
|
|
goto loop;
|
|
}
|
|
|
|
pp = NULL;
|
|
ppri = INT_MIN;
|
|
sx_slock(&allproc_lock);
|
|
FOREACH_PROC_IN_SYSTEM(p) {
|
|
PROC_LOCK(p);
|
|
if (p->p_state == PRS_NEW ||
|
|
p->p_flag & (P_SWAPPINGOUT | P_SWAPPINGIN | P_INMEM)) {
|
|
PROC_UNLOCK(p);
|
|
continue;
|
|
}
|
|
swtime = (ticks - p->p_swtick) / hz;
|
|
FOREACH_THREAD_IN_PROC(p, td) {
|
|
/*
|
|
* An otherwise runnable thread of a process
|
|
* swapped out has only the TDI_SWAPPED bit set.
|
|
*/
|
|
thread_lock(td);
|
|
if (td->td_inhibitors == TDI_SWAPPED) {
|
|
slptime = (ticks - td->td_slptick) / hz;
|
|
pri = swtime + slptime;
|
|
if ((td->td_flags & TDF_SWAPINREQ) == 0)
|
|
pri -= p->p_nice * 8;
|
|
/*
|
|
* if this thread is higher priority
|
|
* and there is enough space, then select
|
|
* this process instead of the previous
|
|
* selection.
|
|
*/
|
|
if (pri > ppri) {
|
|
pp = p;
|
|
ppri = pri;
|
|
}
|
|
}
|
|
thread_unlock(td);
|
|
}
|
|
PROC_UNLOCK(p);
|
|
}
|
|
sx_sunlock(&allproc_lock);
|
|
|
|
/*
|
|
* Nothing to do, back to sleep.
|
|
*/
|
|
if ((p = pp) == NULL) {
|
|
tsleep(&proc0, PVM, "swapin", MAXSLP * hz / 2);
|
|
goto loop;
|
|
}
|
|
PROC_LOCK(p);
|
|
|
|
/*
|
|
* Another process may be bringing or may have already
|
|
* brought this process in while we traverse all threads.
|
|
* Or, this process may even be being swapped out again.
|
|
*/
|
|
if (p->p_flag & (P_INMEM | P_SWAPPINGOUT | P_SWAPPINGIN)) {
|
|
PROC_UNLOCK(p);
|
|
goto loop;
|
|
}
|
|
|
|
/*
|
|
* We would like to bring someone in. (only if there is space).
|
|
* [What checks the space? ]
|
|
*/
|
|
faultin(p);
|
|
PROC_UNLOCK(p);
|
|
goto loop;
|
|
}
|
|
|
|
/*
|
|
* First, if any processes have been sleeping or stopped for at least
|
|
* "swap_idle_threshold1" seconds, they are swapped out. If, however,
|
|
* no such processes exist, then the longest-sleeping or stopped
|
|
* process is swapped out. Finally, and only as a last resort, if
|
|
* there are no sleeping or stopped processes, the longest-resident
|
|
* process is swapped out.
|
|
*/
|
|
static void
|
|
swapout_procs(int action)
|
|
{
|
|
struct proc *p;
|
|
struct thread *td;
|
|
int didswap = 0;
|
|
|
|
retry:
|
|
sx_slock(&allproc_lock);
|
|
FOREACH_PROC_IN_SYSTEM(p) {
|
|
struct vmspace *vm;
|
|
int minslptime = 100000;
|
|
int slptime;
|
|
|
|
PROC_LOCK(p);
|
|
/*
|
|
* Watch out for a process in
|
|
* creation. It may have no
|
|
* address space or lock yet.
|
|
*/
|
|
if (p->p_state == PRS_NEW) {
|
|
PROC_UNLOCK(p);
|
|
continue;
|
|
}
|
|
/*
|
|
* An aio daemon switches its
|
|
* address space while running.
|
|
* Perform a quick check whether
|
|
* a process has P_SYSTEM.
|
|
* Filter out exiting processes.
|
|
*/
|
|
if ((p->p_flag & (P_SYSTEM | P_WEXIT)) != 0) {
|
|
PROC_UNLOCK(p);
|
|
continue;
|
|
}
|
|
_PHOLD_LITE(p);
|
|
PROC_UNLOCK(p);
|
|
sx_sunlock(&allproc_lock);
|
|
|
|
/*
|
|
* Do not swapout a process that
|
|
* is waiting for VM data
|
|
* structures as there is a possible
|
|
* deadlock. Test this first as
|
|
* this may block.
|
|
*
|
|
* Lock the map until swapout
|
|
* finishes, or a thread of this
|
|
* process may attempt to alter
|
|
* the map.
|
|
*/
|
|
vm = vmspace_acquire_ref(p);
|
|
if (vm == NULL)
|
|
goto nextproc2;
|
|
if (!vm_map_trylock(&vm->vm_map))
|
|
goto nextproc1;
|
|
|
|
PROC_LOCK(p);
|
|
if (p->p_lock != 1 || (p->p_flag & (P_STOPPED_SINGLE |
|
|
P_TRACED | P_SYSTEM)) != 0)
|
|
goto nextproc;
|
|
|
|
/*
|
|
* only aiod changes vmspace, however it will be
|
|
* skipped because of the if statement above checking
|
|
* for P_SYSTEM
|
|
*/
|
|
if ((p->p_flag & (P_INMEM|P_SWAPPINGOUT|P_SWAPPINGIN)) != P_INMEM)
|
|
goto nextproc;
|
|
|
|
switch (p->p_state) {
|
|
default:
|
|
/* Don't swap out processes in any sort
|
|
* of 'special' state. */
|
|
break;
|
|
|
|
case PRS_NORMAL:
|
|
/*
|
|
* do not swapout a realtime process
|
|
* Check all the thread groups..
|
|
*/
|
|
FOREACH_THREAD_IN_PROC(p, td) {
|
|
thread_lock(td);
|
|
if (PRI_IS_REALTIME(td->td_pri_class)) {
|
|
thread_unlock(td);
|
|
goto nextproc;
|
|
}
|
|
slptime = (ticks - td->td_slptick) / hz;
|
|
/*
|
|
* Guarantee swap_idle_threshold1
|
|
* time in memory.
|
|
*/
|
|
if (slptime < swap_idle_threshold1) {
|
|
thread_unlock(td);
|
|
goto nextproc;
|
|
}
|
|
|
|
/*
|
|
* Do not swapout a process if it is
|
|
* waiting on a critical event of some
|
|
* kind or there is a thread whose
|
|
* pageable memory may be accessed.
|
|
*
|
|
* This could be refined to support
|
|
* swapping out a thread.
|
|
*/
|
|
if (!thread_safetoswapout(td)) {
|
|
thread_unlock(td);
|
|
goto nextproc;
|
|
}
|
|
/*
|
|
* If the system is under memory stress,
|
|
* or if we are swapping
|
|
* idle processes >= swap_idle_threshold2,
|
|
* then swap the process out.
|
|
*/
|
|
if (((action & VM_SWAP_NORMAL) == 0) &&
|
|
(((action & VM_SWAP_IDLE) == 0) ||
|
|
(slptime < swap_idle_threshold2))) {
|
|
thread_unlock(td);
|
|
goto nextproc;
|
|
}
|
|
|
|
if (minslptime > slptime)
|
|
minslptime = slptime;
|
|
thread_unlock(td);
|
|
}
|
|
|
|
/*
|
|
* If the pageout daemon didn't free enough pages,
|
|
* or if this process is idle and the system is
|
|
* configured to swap proactively, swap it out.
|
|
*/
|
|
if ((action & VM_SWAP_NORMAL) ||
|
|
((action & VM_SWAP_IDLE) &&
|
|
(minslptime > swap_idle_threshold2))) {
|
|
_PRELE(p);
|
|
if (swapout(p) == 0)
|
|
didswap++;
|
|
PROC_UNLOCK(p);
|
|
vm_map_unlock(&vm->vm_map);
|
|
vmspace_free(vm);
|
|
goto retry;
|
|
}
|
|
}
|
|
nextproc:
|
|
PROC_UNLOCK(p);
|
|
vm_map_unlock(&vm->vm_map);
|
|
nextproc1:
|
|
vmspace_free(vm);
|
|
nextproc2:
|
|
sx_slock(&allproc_lock);
|
|
PRELE(p);
|
|
}
|
|
sx_sunlock(&allproc_lock);
|
|
/*
|
|
* If we swapped something out, and another process needed memory,
|
|
* then wakeup the sched process.
|
|
*/
|
|
if (didswap)
|
|
wakeup(&proc0);
|
|
}
|
|
|
|
static void
|
|
swapclear(struct proc *p)
|
|
{
|
|
struct thread *td;
|
|
|
|
PROC_LOCK_ASSERT(p, MA_OWNED);
|
|
|
|
FOREACH_THREAD_IN_PROC(p, td) {
|
|
thread_lock(td);
|
|
td->td_flags |= TDF_INMEM;
|
|
td->td_flags &= ~TDF_SWAPINREQ;
|
|
TD_CLR_SWAPPED(td);
|
|
if (TD_CAN_RUN(td))
|
|
if (setrunnable(td)) {
|
|
#ifdef INVARIANTS
|
|
/*
|
|
* XXX: We just cleared TDI_SWAPPED
|
|
* above and set TDF_INMEM, so this
|
|
* should never happen.
|
|
*/
|
|
panic("not waking up swapper");
|
|
#endif
|
|
}
|
|
thread_unlock(td);
|
|
}
|
|
p->p_flag &= ~(P_SWAPPINGIN | P_SWAPPINGOUT);
|
|
p->p_flag |= P_INMEM;
|
|
}
|
|
|
|
static int
|
|
swapout(struct proc *p)
|
|
{
|
|
struct thread *td;
|
|
|
|
PROC_LOCK_ASSERT(p, MA_OWNED);
|
|
|
|
/*
|
|
* The states of this process and its threads may have changed
|
|
* by now. Assuming that there is only one pageout daemon thread,
|
|
* this process should still be in memory.
|
|
*/
|
|
KASSERT((p->p_flag & (P_INMEM | P_SWAPPINGOUT | P_SWAPPINGIN)) ==
|
|
P_INMEM, ("swapout: lost a swapout race?"));
|
|
|
|
/*
|
|
* remember the process resident count
|
|
*/
|
|
p->p_vmspace->vm_swrss = vmspace_resident_count(p->p_vmspace);
|
|
/*
|
|
* Check and mark all threads before we proceed.
|
|
*/
|
|
p->p_flag &= ~P_INMEM;
|
|
p->p_flag |= P_SWAPPINGOUT;
|
|
FOREACH_THREAD_IN_PROC(p, td) {
|
|
thread_lock(td);
|
|
if (!thread_safetoswapout(td)) {
|
|
thread_unlock(td);
|
|
swapclear(p);
|
|
return (EBUSY);
|
|
}
|
|
td->td_flags &= ~TDF_INMEM;
|
|
TD_SET_SWAPPED(td);
|
|
thread_unlock(td);
|
|
}
|
|
td = FIRST_THREAD_IN_PROC(p);
|
|
++td->td_ru.ru_nswap;
|
|
PROC_UNLOCK(p);
|
|
|
|
/*
|
|
* This list is stable because all threads are now prevented from
|
|
* running. The list is only modified in the context of a running
|
|
* thread in this process.
|
|
*/
|
|
FOREACH_THREAD_IN_PROC(p, td)
|
|
vm_thread_swapout(td);
|
|
|
|
PROC_LOCK(p);
|
|
p->p_flag &= ~P_SWAPPINGOUT;
|
|
p->p_swtick = ticks;
|
|
return (0);
|
|
}
|