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44f1c91610
To reduce the diff struct pcu.cnt field was not renamed, so PCPU_OP(cnt.field) is still used. pc_cnt and pcpu are also used in kvm(3) and vmstat(8). The goal was to not affect externally used KPI. Bump __FreeBSD_version_ in case some out-of-tree module/code relies on the the global cnt variable. Exp-run revealed no ports using it directly. No objection from: arch@ Sponsored by: EMC / Isilon Storage Division
1045 lines
25 KiB
C
1045 lines
25 KiB
C
/*-
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* Copyright (c) 1991, 1993
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* The Regents of the University of California. 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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* 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_glue.c 8.6 (Berkeley) 1/5/94
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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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* 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_vm.h"
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#include "opt_kstack_pages.h"
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#include "opt_kstack_max_pages.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/lock.h>
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#include <sys/malloc.h>
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#include <sys/mutex.h>
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#include <sys/proc.h>
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#include <sys/racct.h>
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#include <sys/resourcevar.h>
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#include <sys/rwlock.h>
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#include <sys/sched.h>
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#include <sys/sf_buf.h>
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#include <sys/shm.h>
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#include <sys/vmmeter.h>
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#include <sys/vmem.h>
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#include <sys/sx.h>
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#include <sys/sysctl.h>
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#include <sys/_kstack_cache.h>
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#include <sys/eventhandler.h>
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#include <sys/kernel.h>
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#include <sys/ktr.h>
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#include <sys/unistd.h>
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#include <vm/vm.h>
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#include <vm/vm_param.h>
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#include <vm/pmap.h>
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#include <vm/vm_map.h>
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#include <vm/vm_page.h>
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#include <vm/vm_pageout.h>
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#include <vm/vm_object.h>
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#include <vm/vm_kern.h>
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#include <vm/vm_extern.h>
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#include <vm/vm_pager.h>
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#include <vm/swap_pager.h>
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#ifndef NO_SWAPPING
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static int swapout(struct proc *);
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static void swapclear(struct proc *);
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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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#endif
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/*
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* MPSAFE
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*
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* WARNING! This code calls vm_map_check_protection() which only checks
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* the associated vm_map_entry range. It does not determine whether the
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* contents of the memory is actually readable or writable. In most cases
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* just checking the vm_map_entry is sufficient within the kernel's address
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* space.
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*/
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int
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kernacc(addr, len, rw)
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void *addr;
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int len, rw;
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{
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boolean_t rv;
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vm_offset_t saddr, eaddr;
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vm_prot_t prot;
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KASSERT((rw & ~VM_PROT_ALL) == 0,
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("illegal ``rw'' argument to kernacc (%x)\n", rw));
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if ((vm_offset_t)addr + len > kernel_map->max_offset ||
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(vm_offset_t)addr + len < (vm_offset_t)addr)
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return (FALSE);
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prot = rw;
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saddr = trunc_page((vm_offset_t)addr);
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eaddr = round_page((vm_offset_t)addr + len);
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vm_map_lock_read(kernel_map);
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rv = vm_map_check_protection(kernel_map, saddr, eaddr, prot);
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vm_map_unlock_read(kernel_map);
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return (rv == TRUE);
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}
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/*
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* MPSAFE
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*
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* WARNING! This code calls vm_map_check_protection() which only checks
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* the associated vm_map_entry range. It does not determine whether the
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* contents of the memory is actually readable or writable. vmapbuf(),
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* vm_fault_quick(), or copyin()/copout()/su*()/fu*() functions should be
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* used in conjuction with this call.
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*/
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int
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useracc(addr, len, rw)
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void *addr;
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int len, rw;
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{
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boolean_t rv;
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vm_prot_t prot;
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vm_map_t map;
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KASSERT((rw & ~VM_PROT_ALL) == 0,
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("illegal ``rw'' argument to useracc (%x)\n", rw));
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prot = rw;
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map = &curproc->p_vmspace->vm_map;
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if ((vm_offset_t)addr + len > vm_map_max(map) ||
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(vm_offset_t)addr + len < (vm_offset_t)addr) {
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return (FALSE);
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}
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vm_map_lock_read(map);
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rv = vm_map_check_protection(map, trunc_page((vm_offset_t)addr),
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round_page((vm_offset_t)addr + len), prot);
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vm_map_unlock_read(map);
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return (rv == TRUE);
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}
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int
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vslock(void *addr, size_t len)
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{
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vm_offset_t end, last, start;
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vm_size_t npages;
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int error;
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last = (vm_offset_t)addr + len;
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start = trunc_page((vm_offset_t)addr);
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end = round_page(last);
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if (last < (vm_offset_t)addr || end < (vm_offset_t)addr)
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return (EINVAL);
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npages = atop(end - start);
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if (npages > vm_page_max_wired)
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return (ENOMEM);
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#if 0
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/*
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* XXX - not yet
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*
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* The limit for transient usage of wired pages should be
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* larger than for "permanent" wired pages (mlock()).
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*
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* Also, the sysctl code, which is the only present user
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* of vslock(), does a hard loop on EAGAIN.
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*/
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if (npages + vm_cnt.v_wire_count > vm_page_max_wired)
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return (EAGAIN);
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#endif
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error = vm_map_wire(&curproc->p_vmspace->vm_map, start, end,
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VM_MAP_WIRE_SYSTEM | VM_MAP_WIRE_NOHOLES);
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/*
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* Return EFAULT on error to match copy{in,out}() behaviour
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* rather than returning ENOMEM like mlock() would.
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*/
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return (error == KERN_SUCCESS ? 0 : EFAULT);
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}
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void
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vsunlock(void *addr, size_t len)
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{
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/* Rely on the parameter sanity checks performed by vslock(). */
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(void)vm_map_unwire(&curproc->p_vmspace->vm_map,
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trunc_page((vm_offset_t)addr), round_page((vm_offset_t)addr + len),
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VM_MAP_WIRE_SYSTEM | VM_MAP_WIRE_NOHOLES);
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}
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/*
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* Pin the page contained within the given object at the given offset. If the
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* page is not resident, allocate and load it using the given object's pager.
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* Return the pinned page if successful; otherwise, return NULL.
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*/
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static vm_page_t
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vm_imgact_hold_page(vm_object_t object, vm_ooffset_t offset)
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{
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vm_page_t m, ma[1];
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vm_pindex_t pindex;
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int rv;
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VM_OBJECT_WLOCK(object);
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pindex = OFF_TO_IDX(offset);
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m = vm_page_grab(object, pindex, VM_ALLOC_NORMAL);
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if (m->valid != VM_PAGE_BITS_ALL) {
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ma[0] = m;
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rv = vm_pager_get_pages(object, ma, 1, 0);
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m = vm_page_lookup(object, pindex);
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if (m == NULL)
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goto out;
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if (rv != VM_PAGER_OK) {
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vm_page_lock(m);
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vm_page_free(m);
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vm_page_unlock(m);
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m = NULL;
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goto out;
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}
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}
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vm_page_xunbusy(m);
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vm_page_lock(m);
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vm_page_hold(m);
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vm_page_unlock(m);
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out:
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VM_OBJECT_WUNLOCK(object);
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return (m);
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}
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/*
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* Return a CPU private mapping to the page at the given offset within the
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* given object. The page is pinned before it is mapped.
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*/
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struct sf_buf *
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vm_imgact_map_page(vm_object_t object, vm_ooffset_t offset)
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{
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vm_page_t m;
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m = vm_imgact_hold_page(object, offset);
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if (m == NULL)
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return (NULL);
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sched_pin();
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return (sf_buf_alloc(m, SFB_CPUPRIVATE));
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}
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/*
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* Destroy the given CPU private mapping and unpin the page that it mapped.
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*/
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void
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vm_imgact_unmap_page(struct sf_buf *sf)
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{
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vm_page_t m;
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m = sf_buf_page(sf);
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sf_buf_free(sf);
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sched_unpin();
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vm_page_lock(m);
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vm_page_unhold(m);
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vm_page_unlock(m);
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}
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void
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vm_sync_icache(vm_map_t map, vm_offset_t va, vm_offset_t sz)
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{
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pmap_sync_icache(map->pmap, va, sz);
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}
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struct kstack_cache_entry *kstack_cache;
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static int kstack_cache_size = 128;
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static int kstacks;
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static struct mtx kstack_cache_mtx;
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MTX_SYSINIT(kstack_cache, &kstack_cache_mtx, "kstkch", MTX_DEF);
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SYSCTL_INT(_vm, OID_AUTO, kstack_cache_size, CTLFLAG_RW, &kstack_cache_size, 0,
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"");
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SYSCTL_INT(_vm, OID_AUTO, kstacks, CTLFLAG_RD, &kstacks, 0,
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"");
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#ifndef KSTACK_MAX_PAGES
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#define KSTACK_MAX_PAGES 32
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#endif
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/*
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* Create the kernel stack (including pcb for i386) for a new thread.
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* This routine directly affects the fork perf for a process and
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* create performance for a thread.
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*/
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int
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vm_thread_new(struct thread *td, int pages)
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{
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vm_object_t ksobj;
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vm_offset_t ks;
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vm_page_t m, ma[KSTACK_MAX_PAGES];
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struct kstack_cache_entry *ks_ce;
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int i;
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/* Bounds check */
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if (pages <= 1)
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pages = KSTACK_PAGES;
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else if (pages > KSTACK_MAX_PAGES)
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pages = KSTACK_MAX_PAGES;
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if (pages == KSTACK_PAGES) {
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mtx_lock(&kstack_cache_mtx);
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if (kstack_cache != NULL) {
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ks_ce = kstack_cache;
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kstack_cache = ks_ce->next_ks_entry;
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mtx_unlock(&kstack_cache_mtx);
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td->td_kstack_obj = ks_ce->ksobj;
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td->td_kstack = (vm_offset_t)ks_ce;
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td->td_kstack_pages = KSTACK_PAGES;
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return (1);
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}
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mtx_unlock(&kstack_cache_mtx);
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}
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/*
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* Allocate an object for the kstack.
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*/
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ksobj = vm_object_allocate(OBJT_DEFAULT, pages);
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/*
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* Get a kernel virtual address for this thread's kstack.
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*/
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#if defined(__mips__)
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/*
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* We need to align the kstack's mapped address to fit within
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* a single TLB entry.
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*/
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if (vmem_xalloc(kernel_arena, (pages + KSTACK_GUARD_PAGES) * PAGE_SIZE,
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PAGE_SIZE * 2, 0, 0, VMEM_ADDR_MIN, VMEM_ADDR_MAX,
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M_BESTFIT | M_NOWAIT, &ks)) {
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ks = 0;
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}
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#else
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ks = kva_alloc((pages + KSTACK_GUARD_PAGES) * PAGE_SIZE);
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#endif
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if (ks == 0) {
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printf("vm_thread_new: kstack allocation failed\n");
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vm_object_deallocate(ksobj);
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return (0);
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}
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atomic_add_int(&kstacks, 1);
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if (KSTACK_GUARD_PAGES != 0) {
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pmap_qremove(ks, KSTACK_GUARD_PAGES);
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ks += KSTACK_GUARD_PAGES * PAGE_SIZE;
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}
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td->td_kstack_obj = ksobj;
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td->td_kstack = ks;
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/*
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* Knowing the number of pages allocated is useful when you
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* want to deallocate them.
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*/
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td->td_kstack_pages = pages;
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/*
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* For the length of the stack, link in a real page of ram for each
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* page of stack.
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*/
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VM_OBJECT_WLOCK(ksobj);
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for (i = 0; i < pages; i++) {
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/*
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* Get a kernel stack page.
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*/
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m = vm_page_grab(ksobj, i, VM_ALLOC_NOBUSY |
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VM_ALLOC_NORMAL | VM_ALLOC_WIRED);
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ma[i] = m;
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m->valid = VM_PAGE_BITS_ALL;
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}
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VM_OBJECT_WUNLOCK(ksobj);
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pmap_qenter(ks, ma, pages);
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return (1);
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}
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|
|
static void
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vm_thread_stack_dispose(vm_object_t ksobj, vm_offset_t ks, int pages)
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{
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vm_page_t m;
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int i;
|
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|
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atomic_add_int(&kstacks, -1);
|
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pmap_qremove(ks, pages);
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VM_OBJECT_WLOCK(ksobj);
|
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for (i = 0; i < pages; i++) {
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m = vm_page_lookup(ksobj, i);
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if (m == NULL)
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panic("vm_thread_dispose: kstack already missing?");
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vm_page_lock(m);
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vm_page_unwire(m, 0);
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vm_page_free(m);
|
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vm_page_unlock(m);
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}
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VM_OBJECT_WUNLOCK(ksobj);
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vm_object_deallocate(ksobj);
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kva_free(ks - (KSTACK_GUARD_PAGES * PAGE_SIZE),
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(pages + KSTACK_GUARD_PAGES) * PAGE_SIZE);
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}
|
|
|
|
/*
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|
* Dispose of a thread's kernel stack.
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|
*/
|
|
void
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vm_thread_dispose(struct thread *td)
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|
{
|
|
vm_object_t ksobj;
|
|
vm_offset_t ks;
|
|
struct kstack_cache_entry *ks_ce;
|
|
int pages;
|
|
|
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pages = td->td_kstack_pages;
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|
ksobj = td->td_kstack_obj;
|
|
ks = td->td_kstack;
|
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td->td_kstack = 0;
|
|
td->td_kstack_pages = 0;
|
|
if (pages == KSTACK_PAGES && kstacks <= kstack_cache_size) {
|
|
ks_ce = (struct kstack_cache_entry *)ks;
|
|
ks_ce->ksobj = ksobj;
|
|
mtx_lock(&kstack_cache_mtx);
|
|
ks_ce->next_ks_entry = kstack_cache;
|
|
kstack_cache = ks_ce;
|
|
mtx_unlock(&kstack_cache_mtx);
|
|
return;
|
|
}
|
|
vm_thread_stack_dispose(ksobj, ks, pages);
|
|
}
|
|
|
|
static void
|
|
vm_thread_stack_lowmem(void *nulll)
|
|
{
|
|
struct kstack_cache_entry *ks_ce, *ks_ce1;
|
|
|
|
mtx_lock(&kstack_cache_mtx);
|
|
ks_ce = kstack_cache;
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|
kstack_cache = NULL;
|
|
mtx_unlock(&kstack_cache_mtx);
|
|
|
|
while (ks_ce != NULL) {
|
|
ks_ce1 = ks_ce;
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|
ks_ce = ks_ce->next_ks_entry;
|
|
|
|
vm_thread_stack_dispose(ks_ce1->ksobj, (vm_offset_t)ks_ce1,
|
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KSTACK_PAGES);
|
|
}
|
|
}
|
|
|
|
static void
|
|
kstack_cache_init(void *nulll)
|
|
{
|
|
|
|
EVENTHANDLER_REGISTER(vm_lowmem, vm_thread_stack_lowmem, NULL,
|
|
EVENTHANDLER_PRI_ANY);
|
|
}
|
|
|
|
SYSINIT(vm_kstacks, SI_SUB_KTHREAD_INIT, SI_ORDER_ANY, kstack_cache_init, NULL);
|
|
|
|
#ifndef NO_SWAPPING
|
|
/*
|
|
* 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, 0);
|
|
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 i, j, k, pages, rv;
|
|
|
|
pages = td->td_kstack_pages;
|
|
ksobj = td->td_kstack_obj;
|
|
VM_OBJECT_WLOCK(ksobj);
|
|
for (i = 0; i < pages; i++)
|
|
ma[i] = vm_page_grab(ksobj, i, VM_ALLOC_NORMAL |
|
|
VM_ALLOC_WIRED);
|
|
for (i = 0; i < pages; i++) {
|
|
if (ma[i]->valid != VM_PAGE_BITS_ALL) {
|
|
vm_page_assert_xbusied(ma[i]);
|
|
vm_object_pip_add(ksobj, 1);
|
|
for (j = i + 1; j < pages; j++) {
|
|
if (ma[j]->valid != VM_PAGE_BITS_ALL)
|
|
vm_page_assert_xbusied(ma[j]);
|
|
if (ma[j]->valid == VM_PAGE_BITS_ALL)
|
|
break;
|
|
}
|
|
rv = vm_pager_get_pages(ksobj, ma + i, j - i, 0);
|
|
if (rv != VM_PAGER_OK)
|
|
panic("vm_thread_swapin: cannot get kstack for proc: %d",
|
|
td->td_proc->p_pid);
|
|
vm_object_pip_wakeup(ksobj);
|
|
for (k = i; k < j; k++)
|
|
ma[k] = vm_page_lookup(ksobj, k);
|
|
vm_page_xunbusy(ma[i]);
|
|
} else if (vm_page_xbusied(ma[i]))
|
|
vm_page_xunbusy(ma[i]);
|
|
}
|
|
VM_OBJECT_WUNLOCK(ksobj);
|
|
pmap_qenter(td->td_kstack, ma, pages);
|
|
cpu_thread_swapin(td);
|
|
}
|
|
#endif /* !NO_SWAPPING */
|
|
|
|
/*
|
|
* Implement fork's actions on an address space.
|
|
* Here we arrange for the address space to be copied or referenced,
|
|
* allocate a user struct (pcb and kernel stack), then call the
|
|
* machine-dependent layer to fill those in and make the new process
|
|
* ready to run. The new process is set up so that it returns directly
|
|
* to user mode to avoid stack copying and relocation problems.
|
|
*/
|
|
int
|
|
vm_forkproc(td, p2, td2, vm2, flags)
|
|
struct thread *td;
|
|
struct proc *p2;
|
|
struct thread *td2;
|
|
struct vmspace *vm2;
|
|
int flags;
|
|
{
|
|
struct proc *p1 = td->td_proc;
|
|
int error;
|
|
|
|
if ((flags & RFPROC) == 0) {
|
|
/*
|
|
* Divorce the memory, if it is shared, essentially
|
|
* this changes shared memory amongst threads, into
|
|
* COW locally.
|
|
*/
|
|
if ((flags & RFMEM) == 0) {
|
|
if (p1->p_vmspace->vm_refcnt > 1) {
|
|
error = vmspace_unshare(p1);
|
|
if (error)
|
|
return (error);
|
|
}
|
|
}
|
|
cpu_fork(td, p2, td2, flags);
|
|
return (0);
|
|
}
|
|
|
|
if (flags & RFMEM) {
|
|
p2->p_vmspace = p1->p_vmspace;
|
|
atomic_add_int(&p1->p_vmspace->vm_refcnt, 1);
|
|
}
|
|
|
|
while (vm_page_count_severe()) {
|
|
VM_WAIT;
|
|
}
|
|
|
|
if ((flags & RFMEM) == 0) {
|
|
p2->p_vmspace = vm2;
|
|
if (p1->p_vmspace->vm_shm)
|
|
shmfork(p1, p2);
|
|
}
|
|
|
|
/*
|
|
* cpu_fork will copy and update the pcb, set up the kernel stack,
|
|
* and make the child ready to run.
|
|
*/
|
|
cpu_fork(td, p2, td2, flags);
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* Called after process has been wait(2)'ed apon and is being reaped.
|
|
* The idea is to reclaim resources that we could not reclaim while
|
|
* the process was still executing.
|
|
*/
|
|
void
|
|
vm_waitproc(p)
|
|
struct proc *p;
|
|
{
|
|
|
|
vmspace_exitfree(p); /* and clean-out the vmspace */
|
|
}
|
|
|
|
void
|
|
faultin(p)
|
|
struct proc *p;
|
|
{
|
|
#ifdef NO_SWAPPING
|
|
|
|
PROC_LOCK_ASSERT(p, MA_OWNED);
|
|
if ((p->p_flag & P_INMEM) == 0)
|
|
panic("faultin: proc swapped out with NO_SWAPPING!");
|
|
#else /* !NO_SWAPPING */
|
|
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;
|
|
}
|
|
#endif /* NO_SWAPPING */
|
|
}
|
|
|
|
/*
|
|
* 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.
|
|
*
|
|
* Giant is held on entry.
|
|
*/
|
|
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;
|
|
}
|
|
|
|
void
|
|
kick_proc0(void)
|
|
{
|
|
|
|
wakeup(&proc0);
|
|
}
|
|
|
|
#ifndef NO_SWAPPING
|
|
|
|
/*
|
|
* Swap_idle_threshold1 is the guaranteed swapped in time for a process
|
|
*/
|
|
static int swap_idle_threshold1 = 2;
|
|
SYSCTL_INT(_vm, OID_AUTO, swap_idle_threshold1, CTLFLAG_RW,
|
|
&swap_idle_threshold1, 0, "Guaranteed swapped in time for a process");
|
|
|
|
/*
|
|
* Swap_idle_threshold2 is the time that a process can be idle before
|
|
* it will be swapped out, if idle swapping is enabled.
|
|
*/
|
|
static int swap_idle_threshold2 = 10;
|
|
SYSCTL_INT(_vm, OID_AUTO, swap_idle_threshold2, CTLFLAG_RW,
|
|
&swap_idle_threshold2, 0, "Time before a process will be swapped out");
|
|
|
|
/*
|
|
* 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.
|
|
*/
|
|
void
|
|
swapout_procs(action)
|
|
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;
|
|
|
|
/*
|
|
* Watch out for a process in
|
|
* creation. It may have no
|
|
* address space or lock yet.
|
|
*/
|
|
if (p->p_state == PRS_NEW)
|
|
continue;
|
|
/*
|
|
* An aio daemon switches its
|
|
* address space while running.
|
|
* Perform a quick check whether
|
|
* a process has P_SYSTEM.
|
|
*/
|
|
if ((p->p_flag & P_SYSTEM) != 0)
|
|
continue;
|
|
/*
|
|
* 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)
|
|
continue;
|
|
if (!vm_map_trylock(&vm->vm_map))
|
|
goto nextproc1;
|
|
|
|
PROC_LOCK(p);
|
|
if (p->p_lock != 0 ||
|
|
(p->p_flag & (P_STOPPED_SINGLE|P_TRACED|P_SYSTEM|P_WEXIT)
|
|
) != 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))) {
|
|
if (swapout(p) == 0)
|
|
didswap++;
|
|
PROC_UNLOCK(p);
|
|
vm_map_unlock(&vm->vm_map);
|
|
vmspace_free(vm);
|
|
sx_sunlock(&allproc_lock);
|
|
goto retry;
|
|
}
|
|
}
|
|
nextproc:
|
|
PROC_UNLOCK(p);
|
|
vm_map_unlock(&vm->vm_map);
|
|
nextproc1:
|
|
vmspace_free(vm);
|
|
continue;
|
|
}
|
|
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(p)
|
|
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(p)
|
|
struct proc *p;
|
|
{
|
|
struct thread *td;
|
|
|
|
PROC_LOCK_ASSERT(p, MA_OWNED);
|
|
#if defined(SWAP_DEBUG)
|
|
printf("swapping out %d\n", p->p_pid);
|
|
#endif
|
|
|
|
/*
|
|
* 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);
|
|
}
|
|
#endif /* !NO_SWAPPING */
|