303fa05a1f
Submitted by: ota@j.email.ne.jp MFC after: 1 week Differential revision: https://reviews.freebsd.org/D22065
3022 lines
78 KiB
C
3022 lines
78 KiB
C
/*-
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* SPDX-License-Identifier: BSD-4-Clause
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*
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* Copyright (c) 1998 Matthew Dillon,
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* Copyright (c) 1994 John S. Dyson
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* Copyright (c) 1990 University of Utah.
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* Copyright (c) 1982, 1986, 1989, 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 Systems Programming Group of the University of Utah Computer
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* Science Department.
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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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* New Swap System
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* Matthew Dillon
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*
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* Radix Bitmap 'blists'.
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*
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* - The new swapper uses the new radix bitmap code. This should scale
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* to arbitrarily small or arbitrarily large swap spaces and an almost
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* arbitrary degree of fragmentation.
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*
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* Features:
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*
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* - on the fly reallocation of swap during putpages. The new system
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* does not try to keep previously allocated swap blocks for dirty
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* pages.
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*
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* - on the fly deallocation of swap
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*
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* - No more garbage collection required. Unnecessarily allocated swap
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* blocks only exist for dirty vm_page_t's now and these are already
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* cycled (in a high-load system) by the pager. We also do on-the-fly
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* removal of invalidated swap blocks when a page is destroyed
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* or renamed.
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*
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* from: Utah $Hdr: swap_pager.c 1.4 91/04/30$
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*
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* @(#)swap_pager.c 8.9 (Berkeley) 3/21/94
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* @(#)vm_swap.c 8.5 (Berkeley) 2/17/94
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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 <sys/param.h>
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#include <sys/bio.h>
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#include <sys/blist.h>
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#include <sys/buf.h>
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#include <sys/conf.h>
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#include <sys/disk.h>
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#include <sys/disklabel.h>
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#include <sys/eventhandler.h>
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#include <sys/fcntl.h>
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#include <sys/lock.h>
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#include <sys/kernel.h>
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#include <sys/mount.h>
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#include <sys/namei.h>
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#include <sys/malloc.h>
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#include <sys/pctrie.h>
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#include <sys/priv.h>
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#include <sys/proc.h>
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#include <sys/racct.h>
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#include <sys/resource.h>
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#include <sys/resourcevar.h>
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#include <sys/rwlock.h>
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#include <sys/sbuf.h>
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#include <sys/sysctl.h>
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#include <sys/sysproto.h>
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#include <sys/systm.h>
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#include <sys/sx.h>
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#include <sys/vmmeter.h>
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#include <sys/vnode.h>
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#include <security/mac/mac_framework.h>
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#include <vm/vm.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_kern.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_pager.h>
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#include <vm/vm_pageout.h>
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#include <vm/vm_param.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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#include <geom/geom.h>
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/*
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* MAX_PAGEOUT_CLUSTER must be a power of 2 between 1 and 64.
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* The 64-page limit is due to the radix code (kern/subr_blist.c).
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*/
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#ifndef MAX_PAGEOUT_CLUSTER
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#define MAX_PAGEOUT_CLUSTER 32
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#endif
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#if !defined(SWB_NPAGES)
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#define SWB_NPAGES MAX_PAGEOUT_CLUSTER
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#endif
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#define SWAP_META_PAGES PCTRIE_COUNT
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/*
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* A swblk structure maps each page index within a
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* SWAP_META_PAGES-aligned and sized range to the address of an
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* on-disk swap block (or SWAPBLK_NONE). The collection of these
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* mappings for an entire vm object is implemented as a pc-trie.
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*/
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struct swblk {
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vm_pindex_t p;
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daddr_t d[SWAP_META_PAGES];
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};
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static MALLOC_DEFINE(M_VMPGDATA, "vm_pgdata", "swap pager private data");
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static struct mtx sw_dev_mtx;
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static TAILQ_HEAD(, swdevt) swtailq = TAILQ_HEAD_INITIALIZER(swtailq);
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static struct swdevt *swdevhd; /* Allocate from here next */
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static int nswapdev; /* Number of swap devices */
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int swap_pager_avail;
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static struct sx swdev_syscall_lock; /* serialize swap(on|off) */
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static u_long swap_reserved;
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static u_long swap_total;
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static int sysctl_page_shift(SYSCTL_HANDLER_ARGS);
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SYSCTL_PROC(_vm, OID_AUTO, swap_reserved, CTLTYPE_U64 | CTLFLAG_RD | CTLFLAG_MPSAFE,
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&swap_reserved, 0, sysctl_page_shift, "A",
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"Amount of swap storage needed to back all allocated anonymous memory.");
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SYSCTL_PROC(_vm, OID_AUTO, swap_total, CTLTYPE_U64 | CTLFLAG_RD | CTLFLAG_MPSAFE,
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&swap_total, 0, sysctl_page_shift, "A",
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"Total amount of available swap storage.");
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static int overcommit = 0;
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SYSCTL_INT(_vm, VM_OVERCOMMIT, overcommit, CTLFLAG_RW, &overcommit, 0,
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"Configure virtual memory overcommit behavior. See tuning(7) "
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"for details.");
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static unsigned long swzone;
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SYSCTL_ULONG(_vm, OID_AUTO, swzone, CTLFLAG_RD, &swzone, 0,
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"Actual size of swap metadata zone");
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static unsigned long swap_maxpages;
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SYSCTL_ULONG(_vm, OID_AUTO, swap_maxpages, CTLFLAG_RD, &swap_maxpages, 0,
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"Maximum amount of swap supported");
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/* bits from overcommit */
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#define SWAP_RESERVE_FORCE_ON (1 << 0)
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#define SWAP_RESERVE_RLIMIT_ON (1 << 1)
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#define SWAP_RESERVE_ALLOW_NONWIRED (1 << 2)
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static int
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sysctl_page_shift(SYSCTL_HANDLER_ARGS)
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{
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uint64_t newval;
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u_long value = *(u_long *)arg1;
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newval = ((uint64_t)value) << PAGE_SHIFT;
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return (sysctl_handle_64(oidp, &newval, 0, req));
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}
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int
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swap_reserve(vm_ooffset_t incr)
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{
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return (swap_reserve_by_cred(incr, curthread->td_ucred));
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}
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int
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swap_reserve_by_cred(vm_ooffset_t incr, struct ucred *cred)
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{
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u_long r, s, prev, pincr;
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int res, error;
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static int curfail;
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static struct timeval lastfail;
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struct uidinfo *uip;
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uip = cred->cr_ruidinfo;
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KASSERT((incr & PAGE_MASK) == 0, ("%s: incr: %ju & PAGE_MASK", __func__,
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(uintmax_t)incr));
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#ifdef RACCT
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if (racct_enable) {
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PROC_LOCK(curproc);
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error = racct_add(curproc, RACCT_SWAP, incr);
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PROC_UNLOCK(curproc);
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if (error != 0)
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return (0);
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}
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#endif
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pincr = atop(incr);
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res = 0;
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prev = atomic_fetchadd_long(&swap_reserved, pincr);
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r = prev + pincr;
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if (overcommit & SWAP_RESERVE_ALLOW_NONWIRED) {
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s = vm_cnt.v_page_count - vm_cnt.v_free_reserved -
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vm_wire_count();
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} else
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s = 0;
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s += swap_total;
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if ((overcommit & SWAP_RESERVE_FORCE_ON) == 0 || r <= s ||
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(error = priv_check(curthread, PRIV_VM_SWAP_NOQUOTA)) == 0) {
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res = 1;
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} else {
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prev = atomic_fetchadd_long(&swap_reserved, -pincr);
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if (prev < pincr)
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panic("swap_reserved < incr on overcommit fail");
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}
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if (res) {
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prev = atomic_fetchadd_long(&uip->ui_vmsize, pincr);
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if ((overcommit & SWAP_RESERVE_RLIMIT_ON) != 0 &&
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prev + pincr > lim_cur(curthread, RLIMIT_SWAP) &&
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priv_check(curthread, PRIV_VM_SWAP_NORLIMIT)) {
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res = 0;
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prev = atomic_fetchadd_long(&uip->ui_vmsize, -pincr);
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if (prev < pincr)
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panic("uip->ui_vmsize < incr on overcommit fail");
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}
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}
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if (!res && ppsratecheck(&lastfail, &curfail, 1)) {
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printf("uid %d, pid %d: swap reservation for %jd bytes failed\n",
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uip->ui_uid, curproc->p_pid, incr);
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}
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#ifdef RACCT
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if (racct_enable && !res) {
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PROC_LOCK(curproc);
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racct_sub(curproc, RACCT_SWAP, incr);
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PROC_UNLOCK(curproc);
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}
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#endif
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return (res);
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}
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void
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swap_reserve_force(vm_ooffset_t incr)
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{
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struct uidinfo *uip;
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u_long pincr;
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KASSERT((incr & PAGE_MASK) == 0, ("%s: incr: %ju & PAGE_MASK", __func__,
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(uintmax_t)incr));
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PROC_LOCK(curproc);
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#ifdef RACCT
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if (racct_enable)
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racct_add_force(curproc, RACCT_SWAP, incr);
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#endif
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pincr = atop(incr);
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atomic_add_long(&swap_reserved, pincr);
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uip = curproc->p_ucred->cr_ruidinfo;
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atomic_add_long(&uip->ui_vmsize, pincr);
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PROC_UNLOCK(curproc);
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}
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void
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swap_release(vm_ooffset_t decr)
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{
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struct ucred *cred;
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PROC_LOCK(curproc);
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cred = curproc->p_ucred;
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swap_release_by_cred(decr, cred);
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PROC_UNLOCK(curproc);
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}
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void
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swap_release_by_cred(vm_ooffset_t decr, struct ucred *cred)
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{
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u_long prev, pdecr;
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struct uidinfo *uip;
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uip = cred->cr_ruidinfo;
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KASSERT((decr & PAGE_MASK) == 0, ("%s: decr: %ju & PAGE_MASK", __func__,
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(uintmax_t)decr));
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pdecr = atop(decr);
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prev = atomic_fetchadd_long(&swap_reserved, -pdecr);
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if (prev < pdecr)
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panic("swap_reserved < decr");
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prev = atomic_fetchadd_long(&uip->ui_vmsize, -pdecr);
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if (prev < pdecr)
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printf("negative vmsize for uid = %d\n", uip->ui_uid);
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#ifdef RACCT
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if (racct_enable)
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racct_sub_cred(cred, RACCT_SWAP, decr);
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#endif
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}
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#define SWM_POP 0x01 /* pop out */
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static int swap_pager_full = 2; /* swap space exhaustion (task killing) */
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static int swap_pager_almost_full = 1; /* swap space exhaustion (w/hysteresis)*/
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static struct mtx swbuf_mtx; /* to sync nsw_wcount_async */
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static int nsw_wcount_async; /* limit async write buffers */
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static int nsw_wcount_async_max;/* assigned maximum */
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static int nsw_cluster_max; /* maximum VOP I/O allowed */
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static int sysctl_swap_async_max(SYSCTL_HANDLER_ARGS);
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SYSCTL_PROC(_vm, OID_AUTO, swap_async_max, CTLTYPE_INT | CTLFLAG_RW |
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CTLFLAG_MPSAFE, NULL, 0, sysctl_swap_async_max, "I",
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"Maximum running async swap ops");
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static int sysctl_swap_fragmentation(SYSCTL_HANDLER_ARGS);
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SYSCTL_PROC(_vm, OID_AUTO, swap_fragmentation, CTLTYPE_STRING | CTLFLAG_RD |
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CTLFLAG_MPSAFE, NULL, 0, sysctl_swap_fragmentation, "A",
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"Swap Fragmentation Info");
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static struct sx sw_alloc_sx;
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/*
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* "named" and "unnamed" anon region objects. Try to reduce the overhead
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* of searching a named list by hashing it just a little.
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*/
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#define NOBJLISTS 8
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#define NOBJLIST(handle) \
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(&swap_pager_object_list[((int)(intptr_t)handle >> 4) & (NOBJLISTS-1)])
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static struct pagerlst swap_pager_object_list[NOBJLISTS];
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static uma_zone_t swwbuf_zone;
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static uma_zone_t swrbuf_zone;
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static uma_zone_t swblk_zone;
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static uma_zone_t swpctrie_zone;
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/*
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* pagerops for OBJT_SWAP - "swap pager". Some ops are also global procedure
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* calls hooked from other parts of the VM system and do not appear here.
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* (see vm/swap_pager.h).
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*/
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static vm_object_t
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swap_pager_alloc(void *handle, vm_ooffset_t size,
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vm_prot_t prot, vm_ooffset_t offset, struct ucred *);
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static void swap_pager_dealloc(vm_object_t object);
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static int swap_pager_getpages(vm_object_t, vm_page_t *, int, int *,
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int *);
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static int swap_pager_getpages_async(vm_object_t, vm_page_t *, int, int *,
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int *, pgo_getpages_iodone_t, void *);
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static void swap_pager_putpages(vm_object_t, vm_page_t *, int, boolean_t, int *);
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static boolean_t
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swap_pager_haspage(vm_object_t object, vm_pindex_t pindex, int *before, int *after);
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static void swap_pager_init(void);
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static void swap_pager_unswapped(vm_page_t);
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static void swap_pager_swapoff(struct swdevt *sp);
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static void swap_pager_update_writecount(vm_object_t object,
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vm_offset_t start, vm_offset_t end);
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static void swap_pager_release_writecount(vm_object_t object,
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vm_offset_t start, vm_offset_t end);
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struct pagerops swappagerops = {
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.pgo_init = swap_pager_init, /* early system initialization of pager */
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.pgo_alloc = swap_pager_alloc, /* allocate an OBJT_SWAP object */
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.pgo_dealloc = swap_pager_dealloc, /* deallocate an OBJT_SWAP object */
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.pgo_getpages = swap_pager_getpages, /* pagein */
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.pgo_getpages_async = swap_pager_getpages_async, /* pagein (async) */
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.pgo_putpages = swap_pager_putpages, /* pageout */
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.pgo_haspage = swap_pager_haspage, /* get backing store status for page */
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.pgo_pageunswapped = swap_pager_unswapped, /* remove swap related to page */
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.pgo_update_writecount = swap_pager_update_writecount,
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.pgo_release_writecount = swap_pager_release_writecount,
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};
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/*
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* swap_*() routines are externally accessible. swp_*() routines are
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* internal.
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*/
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static int nswap_lowat = 128; /* in pages, swap_pager_almost_full warn */
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static int nswap_hiwat = 512; /* in pages, swap_pager_almost_full warn */
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SYSCTL_INT(_vm, OID_AUTO, dmmax, CTLFLAG_RD, &nsw_cluster_max, 0,
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"Maximum size of a swap block in pages");
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static void swp_sizecheck(void);
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static void swp_pager_async_iodone(struct buf *bp);
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static bool swp_pager_swblk_empty(struct swblk *sb, int start, int limit);
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static int swapongeom(struct vnode *);
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static int swaponvp(struct thread *, struct vnode *, u_long);
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static int swapoff_one(struct swdevt *sp, struct ucred *cred);
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/*
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* Swap bitmap functions
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*/
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static void swp_pager_freeswapspace(daddr_t blk, daddr_t npages);
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static daddr_t swp_pager_getswapspace(int *npages, int limit);
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/*
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* Metadata functions
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*/
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static daddr_t swp_pager_meta_build(vm_object_t, vm_pindex_t, daddr_t);
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static void swp_pager_meta_free(vm_object_t, vm_pindex_t, vm_pindex_t);
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static void swp_pager_meta_free_all(vm_object_t);
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static daddr_t swp_pager_meta_ctl(vm_object_t, vm_pindex_t, int);
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static void
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swp_pager_init_freerange(daddr_t *start, daddr_t *num)
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{
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*start = SWAPBLK_NONE;
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*num = 0;
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}
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static void
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swp_pager_update_freerange(daddr_t *start, daddr_t *num, daddr_t addr)
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{
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if (*start + *num == addr) {
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(*num)++;
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} else {
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swp_pager_freeswapspace(*start, *num);
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*start = addr;
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*num = 1;
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}
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}
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static void *
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swblk_trie_alloc(struct pctrie *ptree)
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{
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|
|
|
return (uma_zalloc(swpctrie_zone, M_NOWAIT | (curproc == pageproc ?
|
|
M_USE_RESERVE : 0)));
|
|
}
|
|
|
|
static void
|
|
swblk_trie_free(struct pctrie *ptree, void *node)
|
|
{
|
|
|
|
uma_zfree(swpctrie_zone, node);
|
|
}
|
|
|
|
PCTRIE_DEFINE(SWAP, swblk, p, swblk_trie_alloc, swblk_trie_free);
|
|
|
|
/*
|
|
* SWP_SIZECHECK() - update swap_pager_full indication
|
|
*
|
|
* update the swap_pager_almost_full indication and warn when we are
|
|
* about to run out of swap space, using lowat/hiwat hysteresis.
|
|
*
|
|
* Clear swap_pager_full ( task killing ) indication when lowat is met.
|
|
*
|
|
* No restrictions on call
|
|
* This routine may not block.
|
|
*/
|
|
static void
|
|
swp_sizecheck(void)
|
|
{
|
|
|
|
if (swap_pager_avail < nswap_lowat) {
|
|
if (swap_pager_almost_full == 0) {
|
|
printf("swap_pager: out of swap space\n");
|
|
swap_pager_almost_full = 1;
|
|
}
|
|
} else {
|
|
swap_pager_full = 0;
|
|
if (swap_pager_avail > nswap_hiwat)
|
|
swap_pager_almost_full = 0;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* SWAP_PAGER_INIT() - initialize the swap pager!
|
|
*
|
|
* Expected to be started from system init. NOTE: This code is run
|
|
* before much else so be careful what you depend on. Most of the VM
|
|
* system has yet to be initialized at this point.
|
|
*/
|
|
static void
|
|
swap_pager_init(void)
|
|
{
|
|
/*
|
|
* Initialize object lists
|
|
*/
|
|
int i;
|
|
|
|
for (i = 0; i < NOBJLISTS; ++i)
|
|
TAILQ_INIT(&swap_pager_object_list[i]);
|
|
mtx_init(&sw_dev_mtx, "swapdev", NULL, MTX_DEF);
|
|
sx_init(&sw_alloc_sx, "swspsx");
|
|
sx_init(&swdev_syscall_lock, "swsysc");
|
|
}
|
|
|
|
/*
|
|
* SWAP_PAGER_SWAP_INIT() - swap pager initialization from pageout process
|
|
*
|
|
* Expected to be started from pageout process once, prior to entering
|
|
* its main loop.
|
|
*/
|
|
void
|
|
swap_pager_swap_init(void)
|
|
{
|
|
unsigned long n, n2;
|
|
|
|
/*
|
|
* Number of in-transit swap bp operations. Don't
|
|
* exhaust the pbufs completely. Make sure we
|
|
* initialize workable values (0 will work for hysteresis
|
|
* but it isn't very efficient).
|
|
*
|
|
* The nsw_cluster_max is constrained by the bp->b_pages[]
|
|
* array, which has MAXPHYS / PAGE_SIZE entries, and our locally
|
|
* defined MAX_PAGEOUT_CLUSTER. Also be aware that swap ops are
|
|
* constrained by the swap device interleave stripe size.
|
|
*
|
|
* Currently we hardwire nsw_wcount_async to 4. This limit is
|
|
* designed to prevent other I/O from having high latencies due to
|
|
* our pageout I/O. The value 4 works well for one or two active swap
|
|
* devices but is probably a little low if you have more. Even so,
|
|
* a higher value would probably generate only a limited improvement
|
|
* with three or four active swap devices since the system does not
|
|
* typically have to pageout at extreme bandwidths. We will want
|
|
* at least 2 per swap devices, and 4 is a pretty good value if you
|
|
* have one NFS swap device due to the command/ack latency over NFS.
|
|
* So it all works out pretty well.
|
|
*/
|
|
nsw_cluster_max = min(MAXPHYS / PAGE_SIZE, MAX_PAGEOUT_CLUSTER);
|
|
|
|
nsw_wcount_async = 4;
|
|
nsw_wcount_async_max = nsw_wcount_async;
|
|
mtx_init(&swbuf_mtx, "async swbuf mutex", NULL, MTX_DEF);
|
|
|
|
swwbuf_zone = pbuf_zsecond_create("swwbuf", nswbuf / 4);
|
|
swrbuf_zone = pbuf_zsecond_create("swrbuf", nswbuf / 2);
|
|
|
|
/*
|
|
* Initialize our zone, taking the user's requested size or
|
|
* estimating the number we need based on the number of pages
|
|
* in the system.
|
|
*/
|
|
n = maxswzone != 0 ? maxswzone / sizeof(struct swblk) :
|
|
vm_cnt.v_page_count / 2;
|
|
swpctrie_zone = uma_zcreate("swpctrie", pctrie_node_size(), NULL, NULL,
|
|
pctrie_zone_init, NULL, UMA_ALIGN_PTR, UMA_ZONE_VM);
|
|
if (swpctrie_zone == NULL)
|
|
panic("failed to create swap pctrie zone.");
|
|
swblk_zone = uma_zcreate("swblk", sizeof(struct swblk), NULL, NULL,
|
|
NULL, NULL, _Alignof(struct swblk) - 1, UMA_ZONE_VM);
|
|
if (swblk_zone == NULL)
|
|
panic("failed to create swap blk zone.");
|
|
n2 = n;
|
|
do {
|
|
if (uma_zone_reserve_kva(swblk_zone, n))
|
|
break;
|
|
/*
|
|
* if the allocation failed, try a zone two thirds the
|
|
* size of the previous attempt.
|
|
*/
|
|
n -= ((n + 2) / 3);
|
|
} while (n > 0);
|
|
|
|
/*
|
|
* Often uma_zone_reserve_kva() cannot reserve exactly the
|
|
* requested size. Account for the difference when
|
|
* calculating swap_maxpages.
|
|
*/
|
|
n = uma_zone_get_max(swblk_zone);
|
|
|
|
if (n < n2)
|
|
printf("Swap blk zone entries changed from %lu to %lu.\n",
|
|
n2, n);
|
|
/* absolute maximum we can handle assuming 100% efficiency */
|
|
swap_maxpages = n * SWAP_META_PAGES;
|
|
swzone = n * sizeof(struct swblk);
|
|
if (!uma_zone_reserve_kva(swpctrie_zone, n))
|
|
printf("Cannot reserve swap pctrie zone, "
|
|
"reduce kern.maxswzone.\n");
|
|
}
|
|
|
|
static vm_object_t
|
|
swap_pager_alloc_init(void *handle, struct ucred *cred, vm_ooffset_t size,
|
|
vm_ooffset_t offset)
|
|
{
|
|
vm_object_t object;
|
|
|
|
if (cred != NULL) {
|
|
if (!swap_reserve_by_cred(size, cred))
|
|
return (NULL);
|
|
crhold(cred);
|
|
}
|
|
|
|
/*
|
|
* The un_pager.swp.swp_blks trie is initialized by
|
|
* vm_object_allocate() to ensure the correct order of
|
|
* visibility to other threads.
|
|
*/
|
|
object = vm_object_allocate(OBJT_SWAP, OFF_TO_IDX(offset +
|
|
PAGE_MASK + size));
|
|
|
|
object->un_pager.swp.writemappings = 0;
|
|
object->handle = handle;
|
|
if (cred != NULL) {
|
|
object->cred = cred;
|
|
object->charge = size;
|
|
}
|
|
return (object);
|
|
}
|
|
|
|
/*
|
|
* SWAP_PAGER_ALLOC() - allocate a new OBJT_SWAP VM object and instantiate
|
|
* its metadata structures.
|
|
*
|
|
* This routine is called from the mmap and fork code to create a new
|
|
* OBJT_SWAP object.
|
|
*
|
|
* This routine must ensure that no live duplicate is created for
|
|
* the named object request, which is protected against by
|
|
* holding the sw_alloc_sx lock in case handle != NULL.
|
|
*/
|
|
static vm_object_t
|
|
swap_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot,
|
|
vm_ooffset_t offset, struct ucred *cred)
|
|
{
|
|
vm_object_t object;
|
|
|
|
if (handle != NULL) {
|
|
/*
|
|
* Reference existing named region or allocate new one. There
|
|
* should not be a race here against swp_pager_meta_build()
|
|
* as called from vm_page_remove() in regards to the lookup
|
|
* of the handle.
|
|
*/
|
|
sx_xlock(&sw_alloc_sx);
|
|
object = vm_pager_object_lookup(NOBJLIST(handle), handle);
|
|
if (object == NULL) {
|
|
object = swap_pager_alloc_init(handle, cred, size,
|
|
offset);
|
|
if (object != NULL) {
|
|
TAILQ_INSERT_TAIL(NOBJLIST(object->handle),
|
|
object, pager_object_list);
|
|
}
|
|
}
|
|
sx_xunlock(&sw_alloc_sx);
|
|
} else {
|
|
object = swap_pager_alloc_init(handle, cred, size, offset);
|
|
}
|
|
return (object);
|
|
}
|
|
|
|
/*
|
|
* SWAP_PAGER_DEALLOC() - remove swap metadata from object
|
|
*
|
|
* The swap backing for the object is destroyed. The code is
|
|
* designed such that we can reinstantiate it later, but this
|
|
* routine is typically called only when the entire object is
|
|
* about to be destroyed.
|
|
*
|
|
* The object must be locked.
|
|
*/
|
|
static void
|
|
swap_pager_dealloc(vm_object_t object)
|
|
{
|
|
|
|
VM_OBJECT_ASSERT_WLOCKED(object);
|
|
KASSERT((object->flags & OBJ_DEAD) != 0, ("dealloc of reachable obj"));
|
|
|
|
/*
|
|
* Remove from list right away so lookups will fail if we block for
|
|
* pageout completion.
|
|
*/
|
|
if (object->handle != NULL) {
|
|
VM_OBJECT_WUNLOCK(object);
|
|
sx_xlock(&sw_alloc_sx);
|
|
TAILQ_REMOVE(NOBJLIST(object->handle), object,
|
|
pager_object_list);
|
|
sx_xunlock(&sw_alloc_sx);
|
|
VM_OBJECT_WLOCK(object);
|
|
}
|
|
|
|
vm_object_pip_wait(object, "swpdea");
|
|
|
|
/*
|
|
* Free all remaining metadata. We only bother to free it from
|
|
* the swap meta data. We do not attempt to free swapblk's still
|
|
* associated with vm_page_t's for this object. We do not care
|
|
* if paging is still in progress on some objects.
|
|
*/
|
|
swp_pager_meta_free_all(object);
|
|
object->handle = NULL;
|
|
object->type = OBJT_DEAD;
|
|
}
|
|
|
|
/************************************************************************
|
|
* SWAP PAGER BITMAP ROUTINES *
|
|
************************************************************************/
|
|
|
|
/*
|
|
* SWP_PAGER_GETSWAPSPACE() - allocate raw swap space
|
|
*
|
|
* Allocate swap for up to the requested number of pages, and at
|
|
* least a minimum number of pages. The starting swap block number
|
|
* (a page index) is returned or SWAPBLK_NONE if the allocation
|
|
* failed.
|
|
*
|
|
* Also has the side effect of advising that somebody made a mistake
|
|
* when they configured swap and didn't configure enough.
|
|
*
|
|
* This routine may not sleep.
|
|
*
|
|
* We allocate in round-robin fashion from the configured devices.
|
|
*/
|
|
static daddr_t
|
|
swp_pager_getswapspace(int *io_npages, int limit)
|
|
{
|
|
daddr_t blk;
|
|
struct swdevt *sp;
|
|
int mpages, npages;
|
|
|
|
blk = SWAPBLK_NONE;
|
|
mpages = *io_npages;
|
|
npages = imin(BLIST_MAX_ALLOC, mpages);
|
|
mtx_lock(&sw_dev_mtx);
|
|
sp = swdevhd;
|
|
while (!TAILQ_EMPTY(&swtailq)) {
|
|
if (sp == NULL)
|
|
sp = TAILQ_FIRST(&swtailq);
|
|
if ((sp->sw_flags & SW_CLOSING) == 0)
|
|
blk = blist_alloc(sp->sw_blist, &npages, mpages);
|
|
if (blk != SWAPBLK_NONE)
|
|
break;
|
|
sp = TAILQ_NEXT(sp, sw_list);
|
|
if (swdevhd == sp) {
|
|
if (npages <= limit)
|
|
break;
|
|
mpages = npages - 1;
|
|
npages >>= 1;
|
|
}
|
|
}
|
|
if (blk != SWAPBLK_NONE) {
|
|
*io_npages = npages;
|
|
blk += sp->sw_first;
|
|
sp->sw_used += npages;
|
|
swap_pager_avail -= npages;
|
|
swp_sizecheck();
|
|
swdevhd = TAILQ_NEXT(sp, sw_list);
|
|
} else {
|
|
if (swap_pager_full != 2) {
|
|
printf("swp_pager_getswapspace(%d): failed\n",
|
|
*io_npages);
|
|
swap_pager_full = 2;
|
|
swap_pager_almost_full = 1;
|
|
}
|
|
swdevhd = NULL;
|
|
}
|
|
mtx_unlock(&sw_dev_mtx);
|
|
return (blk);
|
|
}
|
|
|
|
static bool
|
|
swp_pager_isondev(daddr_t blk, struct swdevt *sp)
|
|
{
|
|
|
|
return (blk >= sp->sw_first && blk < sp->sw_end);
|
|
}
|
|
|
|
static void
|
|
swp_pager_strategy(struct buf *bp)
|
|
{
|
|
struct swdevt *sp;
|
|
|
|
mtx_lock(&sw_dev_mtx);
|
|
TAILQ_FOREACH(sp, &swtailq, sw_list) {
|
|
if (swp_pager_isondev(bp->b_blkno, sp)) {
|
|
mtx_unlock(&sw_dev_mtx);
|
|
if ((sp->sw_flags & SW_UNMAPPED) != 0 &&
|
|
unmapped_buf_allowed) {
|
|
bp->b_data = unmapped_buf;
|
|
bp->b_offset = 0;
|
|
} else {
|
|
pmap_qenter((vm_offset_t)bp->b_data,
|
|
&bp->b_pages[0], bp->b_bcount / PAGE_SIZE);
|
|
}
|
|
sp->sw_strategy(bp, sp);
|
|
return;
|
|
}
|
|
}
|
|
panic("Swapdev not found");
|
|
}
|
|
|
|
|
|
/*
|
|
* SWP_PAGER_FREESWAPSPACE() - free raw swap space
|
|
*
|
|
* This routine returns the specified swap blocks back to the bitmap.
|
|
*
|
|
* This routine may not sleep.
|
|
*/
|
|
static void
|
|
swp_pager_freeswapspace(daddr_t blk, daddr_t npages)
|
|
{
|
|
struct swdevt *sp;
|
|
|
|
if (npages == 0)
|
|
return;
|
|
mtx_lock(&sw_dev_mtx);
|
|
TAILQ_FOREACH(sp, &swtailq, sw_list) {
|
|
if (swp_pager_isondev(blk, sp)) {
|
|
sp->sw_used -= npages;
|
|
/*
|
|
* If we are attempting to stop swapping on
|
|
* this device, we don't want to mark any
|
|
* blocks free lest they be reused.
|
|
*/
|
|
if ((sp->sw_flags & SW_CLOSING) == 0) {
|
|
blist_free(sp->sw_blist, blk - sp->sw_first,
|
|
npages);
|
|
swap_pager_avail += npages;
|
|
swp_sizecheck();
|
|
}
|
|
mtx_unlock(&sw_dev_mtx);
|
|
return;
|
|
}
|
|
}
|
|
panic("Swapdev not found");
|
|
}
|
|
|
|
/*
|
|
* SYSCTL_SWAP_FRAGMENTATION() - produce raw swap space stats
|
|
*/
|
|
static int
|
|
sysctl_swap_fragmentation(SYSCTL_HANDLER_ARGS)
|
|
{
|
|
struct sbuf sbuf;
|
|
struct swdevt *sp;
|
|
const char *devname;
|
|
int error;
|
|
|
|
error = sysctl_wire_old_buffer(req, 0);
|
|
if (error != 0)
|
|
return (error);
|
|
sbuf_new_for_sysctl(&sbuf, NULL, 128, req);
|
|
mtx_lock(&sw_dev_mtx);
|
|
TAILQ_FOREACH(sp, &swtailq, sw_list) {
|
|
if (vn_isdisk(sp->sw_vp, NULL))
|
|
devname = devtoname(sp->sw_vp->v_rdev);
|
|
else
|
|
devname = "[file]";
|
|
sbuf_printf(&sbuf, "\nFree space on device %s:\n", devname);
|
|
blist_stats(sp->sw_blist, &sbuf);
|
|
}
|
|
mtx_unlock(&sw_dev_mtx);
|
|
error = sbuf_finish(&sbuf);
|
|
sbuf_delete(&sbuf);
|
|
return (error);
|
|
}
|
|
|
|
/*
|
|
* SWAP_PAGER_FREESPACE() - frees swap blocks associated with a page
|
|
* range within an object.
|
|
*
|
|
* This is a globally accessible routine.
|
|
*
|
|
* This routine removes swapblk assignments from swap metadata.
|
|
*
|
|
* The external callers of this routine typically have already destroyed
|
|
* or renamed vm_page_t's associated with this range in the object so
|
|
* we should be ok.
|
|
*
|
|
* The object must be locked.
|
|
*/
|
|
void
|
|
swap_pager_freespace(vm_object_t object, vm_pindex_t start, vm_size_t size)
|
|
{
|
|
|
|
swp_pager_meta_free(object, start, size);
|
|
}
|
|
|
|
/*
|
|
* SWAP_PAGER_RESERVE() - reserve swap blocks in object
|
|
*
|
|
* Assigns swap blocks to the specified range within the object. The
|
|
* swap blocks are not zeroed. Any previous swap assignment is destroyed.
|
|
*
|
|
* Returns 0 on success, -1 on failure.
|
|
*/
|
|
int
|
|
swap_pager_reserve(vm_object_t object, vm_pindex_t start, vm_size_t size)
|
|
{
|
|
daddr_t addr, blk, n_free, s_free;
|
|
int i, j, n;
|
|
|
|
swp_pager_init_freerange(&s_free, &n_free);
|
|
VM_OBJECT_WLOCK(object);
|
|
for (i = 0; i < size; i += n) {
|
|
n = size - i;
|
|
blk = swp_pager_getswapspace(&n, 1);
|
|
if (blk == SWAPBLK_NONE) {
|
|
swp_pager_meta_free(object, start, i);
|
|
VM_OBJECT_WUNLOCK(object);
|
|
return (-1);
|
|
}
|
|
for (j = 0; j < n; ++j) {
|
|
addr = swp_pager_meta_build(object,
|
|
start + i + j, blk + j);
|
|
if (addr != SWAPBLK_NONE)
|
|
swp_pager_update_freerange(&s_free, &n_free,
|
|
addr);
|
|
}
|
|
}
|
|
swp_pager_freeswapspace(s_free, n_free);
|
|
VM_OBJECT_WUNLOCK(object);
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* SWAP_PAGER_COPY() - copy blocks from source pager to destination pager
|
|
* and destroy the source.
|
|
*
|
|
* Copy any valid swapblks from the source to the destination. In
|
|
* cases where both the source and destination have a valid swapblk,
|
|
* we keep the destination's.
|
|
*
|
|
* This routine is allowed to sleep. It may sleep allocating metadata
|
|
* indirectly through swp_pager_meta_build() or if paging is still in
|
|
* progress on the source.
|
|
*
|
|
* The source object contains no vm_page_t's (which is just as well)
|
|
*
|
|
* The source object is of type OBJT_SWAP.
|
|
*
|
|
* The source and destination objects must be locked.
|
|
* Both object locks may temporarily be released.
|
|
*/
|
|
void
|
|
swap_pager_copy(vm_object_t srcobject, vm_object_t dstobject,
|
|
vm_pindex_t offset, int destroysource)
|
|
{
|
|
vm_pindex_t i;
|
|
daddr_t dstaddr, n_free, s_free, srcaddr;
|
|
|
|
VM_OBJECT_ASSERT_WLOCKED(srcobject);
|
|
VM_OBJECT_ASSERT_WLOCKED(dstobject);
|
|
|
|
/*
|
|
* If destroysource is set, we remove the source object from the
|
|
* swap_pager internal queue now.
|
|
*/
|
|
if (destroysource && srcobject->handle != NULL) {
|
|
vm_object_pip_add(srcobject, 1);
|
|
VM_OBJECT_WUNLOCK(srcobject);
|
|
vm_object_pip_add(dstobject, 1);
|
|
VM_OBJECT_WUNLOCK(dstobject);
|
|
sx_xlock(&sw_alloc_sx);
|
|
TAILQ_REMOVE(NOBJLIST(srcobject->handle), srcobject,
|
|
pager_object_list);
|
|
sx_xunlock(&sw_alloc_sx);
|
|
VM_OBJECT_WLOCK(dstobject);
|
|
vm_object_pip_wakeup(dstobject);
|
|
VM_OBJECT_WLOCK(srcobject);
|
|
vm_object_pip_wakeup(srcobject);
|
|
}
|
|
|
|
/*
|
|
* Transfer source to destination.
|
|
*/
|
|
swp_pager_init_freerange(&s_free, &n_free);
|
|
for (i = 0; i < dstobject->size; ++i) {
|
|
srcaddr = swp_pager_meta_ctl(srcobject, i + offset, SWM_POP);
|
|
if (srcaddr == SWAPBLK_NONE)
|
|
continue;
|
|
dstaddr = swp_pager_meta_ctl(dstobject, i, 0);
|
|
if (dstaddr != SWAPBLK_NONE) {
|
|
/*
|
|
* Destination has valid swapblk or it is represented
|
|
* by a resident page. We destroy the source block.
|
|
*/
|
|
swp_pager_update_freerange(&s_free, &n_free, srcaddr);
|
|
continue;
|
|
}
|
|
|
|
/*
|
|
* Destination has no swapblk and is not resident,
|
|
* copy source.
|
|
*
|
|
* swp_pager_meta_build() can sleep.
|
|
*/
|
|
vm_object_pip_add(srcobject, 1);
|
|
VM_OBJECT_WUNLOCK(srcobject);
|
|
vm_object_pip_add(dstobject, 1);
|
|
dstaddr = swp_pager_meta_build(dstobject, i, srcaddr);
|
|
KASSERT(dstaddr == SWAPBLK_NONE,
|
|
("Unexpected destination swapblk"));
|
|
vm_object_pip_wakeup(dstobject);
|
|
VM_OBJECT_WLOCK(srcobject);
|
|
vm_object_pip_wakeup(srcobject);
|
|
}
|
|
swp_pager_freeswapspace(s_free, n_free);
|
|
|
|
/*
|
|
* Free left over swap blocks in source.
|
|
*
|
|
* We have to revert the type to OBJT_DEFAULT so we do not accidentally
|
|
* double-remove the object from the swap queues.
|
|
*/
|
|
if (destroysource) {
|
|
swp_pager_meta_free_all(srcobject);
|
|
/*
|
|
* Reverting the type is not necessary, the caller is going
|
|
* to destroy srcobject directly, but I'm doing it here
|
|
* for consistency since we've removed the object from its
|
|
* queues.
|
|
*/
|
|
srcobject->type = OBJT_DEFAULT;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* SWAP_PAGER_HASPAGE() - determine if we have good backing store for
|
|
* the requested page.
|
|
*
|
|
* We determine whether good backing store exists for the requested
|
|
* page and return TRUE if it does, FALSE if it doesn't.
|
|
*
|
|
* If TRUE, we also try to determine how much valid, contiguous backing
|
|
* store exists before and after the requested page.
|
|
*/
|
|
static boolean_t
|
|
swap_pager_haspage(vm_object_t object, vm_pindex_t pindex, int *before,
|
|
int *after)
|
|
{
|
|
daddr_t blk, blk0;
|
|
int i;
|
|
|
|
VM_OBJECT_ASSERT_LOCKED(object);
|
|
|
|
/*
|
|
* do we have good backing store at the requested index ?
|
|
*/
|
|
blk0 = swp_pager_meta_ctl(object, pindex, 0);
|
|
if (blk0 == SWAPBLK_NONE) {
|
|
if (before)
|
|
*before = 0;
|
|
if (after)
|
|
*after = 0;
|
|
return (FALSE);
|
|
}
|
|
|
|
/*
|
|
* find backwards-looking contiguous good backing store
|
|
*/
|
|
if (before != NULL) {
|
|
for (i = 1; i < SWB_NPAGES; i++) {
|
|
if (i > pindex)
|
|
break;
|
|
blk = swp_pager_meta_ctl(object, pindex - i, 0);
|
|
if (blk != blk0 - i)
|
|
break;
|
|
}
|
|
*before = i - 1;
|
|
}
|
|
|
|
/*
|
|
* find forward-looking contiguous good backing store
|
|
*/
|
|
if (after != NULL) {
|
|
for (i = 1; i < SWB_NPAGES; i++) {
|
|
blk = swp_pager_meta_ctl(object, pindex + i, 0);
|
|
if (blk != blk0 + i)
|
|
break;
|
|
}
|
|
*after = i - 1;
|
|
}
|
|
return (TRUE);
|
|
}
|
|
|
|
/*
|
|
* SWAP_PAGER_PAGE_UNSWAPPED() - remove swap backing store related to page
|
|
*
|
|
* This removes any associated swap backing store, whether valid or
|
|
* not, from the page.
|
|
*
|
|
* This routine is typically called when a page is made dirty, at
|
|
* which point any associated swap can be freed. MADV_FREE also
|
|
* calls us in a special-case situation
|
|
*
|
|
* NOTE!!! If the page is clean and the swap was valid, the caller
|
|
* should make the page dirty before calling this routine. This routine
|
|
* does NOT change the m->dirty status of the page. Also: MADV_FREE
|
|
* depends on it.
|
|
*
|
|
* This routine may not sleep.
|
|
*
|
|
* The object containing the page must be locked.
|
|
*/
|
|
static void
|
|
swap_pager_unswapped(vm_page_t m)
|
|
{
|
|
daddr_t srcaddr;
|
|
|
|
srcaddr = swp_pager_meta_ctl(m->object, m->pindex, SWM_POP);
|
|
if (srcaddr != SWAPBLK_NONE)
|
|
swp_pager_freeswapspace(srcaddr, 1);
|
|
}
|
|
|
|
/*
|
|
* swap_pager_getpages() - bring pages in from swap
|
|
*
|
|
* Attempt to page in the pages in array "ma" of length "count". The
|
|
* caller may optionally specify that additional pages preceding and
|
|
* succeeding the specified range be paged in. The number of such pages
|
|
* is returned in the "rbehind" and "rahead" parameters, and they will
|
|
* be in the inactive queue upon return.
|
|
*
|
|
* The pages in "ma" must be busied and will remain busied upon return.
|
|
*/
|
|
static int
|
|
swap_pager_getpages(vm_object_t object, vm_page_t *ma, int count, int *rbehind,
|
|
int *rahead)
|
|
{
|
|
struct buf *bp;
|
|
vm_page_t bm, mpred, msucc, p;
|
|
vm_pindex_t pindex;
|
|
daddr_t blk;
|
|
int i, maxahead, maxbehind, reqcount;
|
|
|
|
reqcount = count;
|
|
|
|
/*
|
|
* Determine the final number of read-behind pages and
|
|
* allocate them BEFORE releasing the object lock. Otherwise,
|
|
* there can be a problematic race with vm_object_split().
|
|
* Specifically, vm_object_split() might first transfer pages
|
|
* that precede ma[0] in the current object to a new object,
|
|
* and then this function incorrectly recreates those pages as
|
|
* read-behind pages in the current object.
|
|
*/
|
|
if (!swap_pager_haspage(object, ma[0]->pindex, &maxbehind, &maxahead))
|
|
return (VM_PAGER_FAIL);
|
|
|
|
/*
|
|
* Clip the readahead and readbehind ranges to exclude resident pages.
|
|
*/
|
|
if (rahead != NULL) {
|
|
KASSERT(reqcount - 1 <= maxahead,
|
|
("page count %d extends beyond swap block", reqcount));
|
|
*rahead = imin(*rahead, maxahead - (reqcount - 1));
|
|
pindex = ma[reqcount - 1]->pindex;
|
|
msucc = TAILQ_NEXT(ma[reqcount - 1], listq);
|
|
if (msucc != NULL && msucc->pindex - pindex - 1 < *rahead)
|
|
*rahead = msucc->pindex - pindex - 1;
|
|
}
|
|
if (rbehind != NULL) {
|
|
*rbehind = imin(*rbehind, maxbehind);
|
|
pindex = ma[0]->pindex;
|
|
mpred = TAILQ_PREV(ma[0], pglist, listq);
|
|
if (mpred != NULL && pindex - mpred->pindex - 1 < *rbehind)
|
|
*rbehind = pindex - mpred->pindex - 1;
|
|
}
|
|
|
|
bm = ma[0];
|
|
for (i = 0; i < count; i++)
|
|
ma[i]->oflags |= VPO_SWAPINPROG;
|
|
|
|
/*
|
|
* Allocate readahead and readbehind pages.
|
|
*/
|
|
if (rbehind != NULL) {
|
|
for (i = 1; i <= *rbehind; i++) {
|
|
p = vm_page_alloc(object, ma[0]->pindex - i,
|
|
VM_ALLOC_NORMAL);
|
|
if (p == NULL)
|
|
break;
|
|
p->oflags |= VPO_SWAPINPROG;
|
|
bm = p;
|
|
}
|
|
*rbehind = i - 1;
|
|
}
|
|
if (rahead != NULL) {
|
|
for (i = 0; i < *rahead; i++) {
|
|
p = vm_page_alloc(object,
|
|
ma[reqcount - 1]->pindex + i + 1, VM_ALLOC_NORMAL);
|
|
if (p == NULL)
|
|
break;
|
|
p->oflags |= VPO_SWAPINPROG;
|
|
}
|
|
*rahead = i;
|
|
}
|
|
if (rbehind != NULL)
|
|
count += *rbehind;
|
|
if (rahead != NULL)
|
|
count += *rahead;
|
|
|
|
vm_object_pip_add(object, count);
|
|
|
|
pindex = bm->pindex;
|
|
blk = swp_pager_meta_ctl(object, pindex, 0);
|
|
KASSERT(blk != SWAPBLK_NONE,
|
|
("no swap blocking containing %p(%jx)", object, (uintmax_t)pindex));
|
|
|
|
VM_OBJECT_WUNLOCK(object);
|
|
bp = uma_zalloc(swrbuf_zone, M_WAITOK);
|
|
/* Pages cannot leave the object while busy. */
|
|
for (i = 0, p = bm; i < count; i++, p = TAILQ_NEXT(p, listq)) {
|
|
MPASS(p->pindex == bm->pindex + i);
|
|
bp->b_pages[i] = p;
|
|
}
|
|
|
|
bp->b_flags |= B_PAGING;
|
|
bp->b_iocmd = BIO_READ;
|
|
bp->b_iodone = swp_pager_async_iodone;
|
|
bp->b_rcred = crhold(thread0.td_ucred);
|
|
bp->b_wcred = crhold(thread0.td_ucred);
|
|
bp->b_blkno = blk;
|
|
bp->b_bcount = PAGE_SIZE * count;
|
|
bp->b_bufsize = PAGE_SIZE * count;
|
|
bp->b_npages = count;
|
|
bp->b_pgbefore = rbehind != NULL ? *rbehind : 0;
|
|
bp->b_pgafter = rahead != NULL ? *rahead : 0;
|
|
|
|
VM_CNT_INC(v_swapin);
|
|
VM_CNT_ADD(v_swappgsin, count);
|
|
|
|
/*
|
|
* perform the I/O. NOTE!!! bp cannot be considered valid after
|
|
* this point because we automatically release it on completion.
|
|
* Instead, we look at the one page we are interested in which we
|
|
* still hold a lock on even through the I/O completion.
|
|
*
|
|
* The other pages in our ma[] array are also released on completion,
|
|
* so we cannot assume they are valid anymore either.
|
|
*
|
|
* NOTE: b_blkno is destroyed by the call to swapdev_strategy
|
|
*/
|
|
BUF_KERNPROC(bp);
|
|
swp_pager_strategy(bp);
|
|
|
|
/*
|
|
* Wait for the pages we want to complete. VPO_SWAPINPROG is always
|
|
* cleared on completion. If an I/O error occurs, SWAPBLK_NONE
|
|
* is set in the metadata for each page in the request.
|
|
*/
|
|
VM_OBJECT_WLOCK(object);
|
|
while ((ma[0]->oflags & VPO_SWAPINPROG) != 0) {
|
|
ma[0]->oflags |= VPO_SWAPSLEEP;
|
|
VM_CNT_INC(v_intrans);
|
|
if (VM_OBJECT_SLEEP(object, &object->handle, PSWP,
|
|
"swread", hz * 20)) {
|
|
printf(
|
|
"swap_pager: indefinite wait buffer: bufobj: %p, blkno: %jd, size: %ld\n",
|
|
bp->b_bufobj, (intmax_t)bp->b_blkno, bp->b_bcount);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* If we had an unrecoverable read error pages will not be valid.
|
|
*/
|
|
for (i = 0; i < reqcount; i++)
|
|
if (ma[i]->valid != VM_PAGE_BITS_ALL)
|
|
return (VM_PAGER_ERROR);
|
|
|
|
return (VM_PAGER_OK);
|
|
|
|
/*
|
|
* A final note: in a low swap situation, we cannot deallocate swap
|
|
* and mark a page dirty here because the caller is likely to mark
|
|
* the page clean when we return, causing the page to possibly revert
|
|
* to all-zero's later.
|
|
*/
|
|
}
|
|
|
|
/*
|
|
* swap_pager_getpages_async():
|
|
*
|
|
* Right now this is emulation of asynchronous operation on top of
|
|
* swap_pager_getpages().
|
|
*/
|
|
static int
|
|
swap_pager_getpages_async(vm_object_t object, vm_page_t *ma, int count,
|
|
int *rbehind, int *rahead, pgo_getpages_iodone_t iodone, void *arg)
|
|
{
|
|
int r, error;
|
|
|
|
r = swap_pager_getpages(object, ma, count, rbehind, rahead);
|
|
VM_OBJECT_WUNLOCK(object);
|
|
switch (r) {
|
|
case VM_PAGER_OK:
|
|
error = 0;
|
|
break;
|
|
case VM_PAGER_ERROR:
|
|
error = EIO;
|
|
break;
|
|
case VM_PAGER_FAIL:
|
|
error = EINVAL;
|
|
break;
|
|
default:
|
|
panic("unhandled swap_pager_getpages() error %d", r);
|
|
}
|
|
(iodone)(arg, ma, count, error);
|
|
VM_OBJECT_WLOCK(object);
|
|
|
|
return (r);
|
|
}
|
|
|
|
/*
|
|
* swap_pager_putpages:
|
|
*
|
|
* Assign swap (if necessary) and initiate I/O on the specified pages.
|
|
*
|
|
* We support both OBJT_DEFAULT and OBJT_SWAP objects. DEFAULT objects
|
|
* are automatically converted to SWAP objects.
|
|
*
|
|
* In a low memory situation we may block in VOP_STRATEGY(), but the new
|
|
* vm_page reservation system coupled with properly written VFS devices
|
|
* should ensure that no low-memory deadlock occurs. This is an area
|
|
* which needs work.
|
|
*
|
|
* The parent has N vm_object_pip_add() references prior to
|
|
* calling us and will remove references for rtvals[] that are
|
|
* not set to VM_PAGER_PEND. We need to remove the rest on I/O
|
|
* completion.
|
|
*
|
|
* The parent has soft-busy'd the pages it passes us and will unbusy
|
|
* those whose rtvals[] entry is not set to VM_PAGER_PEND on return.
|
|
* We need to unbusy the rest on I/O completion.
|
|
*/
|
|
static void
|
|
swap_pager_putpages(vm_object_t object, vm_page_t *ma, int count,
|
|
int flags, int *rtvals)
|
|
{
|
|
struct buf *bp;
|
|
daddr_t addr, blk, n_free, s_free;
|
|
vm_page_t mreq;
|
|
int i, j, n;
|
|
bool async;
|
|
|
|
KASSERT(count == 0 || ma[0]->object == object,
|
|
("%s: object mismatch %p/%p",
|
|
__func__, object, ma[0]->object));
|
|
|
|
/*
|
|
* Step 1
|
|
*
|
|
* Turn object into OBJT_SWAP. Force sync if not a pageout process.
|
|
*/
|
|
if (object->type != OBJT_SWAP) {
|
|
addr = swp_pager_meta_build(object, 0, SWAPBLK_NONE);
|
|
KASSERT(addr == SWAPBLK_NONE,
|
|
("unexpected object swap block"));
|
|
}
|
|
VM_OBJECT_WUNLOCK(object);
|
|
async = curproc == pageproc && (flags & VM_PAGER_PUT_SYNC) == 0;
|
|
swp_pager_init_freerange(&s_free, &n_free);
|
|
|
|
/*
|
|
* Step 2
|
|
*
|
|
* Assign swap blocks and issue I/O. We reallocate swap on the fly.
|
|
* The page is left dirty until the pageout operation completes
|
|
* successfully.
|
|
*/
|
|
for (i = 0; i < count; i += n) {
|
|
/* Maximum I/O size is limited by maximum swap block size. */
|
|
n = min(count - i, nsw_cluster_max);
|
|
|
|
/* Get a block of swap of size up to size n. */
|
|
blk = swp_pager_getswapspace(&n, 4);
|
|
if (blk == SWAPBLK_NONE) {
|
|
for (j = 0; j < n; ++j)
|
|
rtvals[i + j] = VM_PAGER_FAIL;
|
|
continue;
|
|
}
|
|
|
|
/*
|
|
* All I/O parameters have been satisfied. Build the I/O
|
|
* request and assign the swap space.
|
|
*/
|
|
if (async) {
|
|
mtx_lock(&swbuf_mtx);
|
|
while (nsw_wcount_async == 0)
|
|
msleep(&nsw_wcount_async, &swbuf_mtx, PVM,
|
|
"swbufa", 0);
|
|
nsw_wcount_async--;
|
|
mtx_unlock(&swbuf_mtx);
|
|
}
|
|
bp = uma_zalloc(swwbuf_zone, M_WAITOK);
|
|
if (async)
|
|
bp->b_flags = B_ASYNC;
|
|
bp->b_flags |= B_PAGING;
|
|
bp->b_iocmd = BIO_WRITE;
|
|
|
|
bp->b_rcred = crhold(thread0.td_ucred);
|
|
bp->b_wcred = crhold(thread0.td_ucred);
|
|
bp->b_bcount = PAGE_SIZE * n;
|
|
bp->b_bufsize = PAGE_SIZE * n;
|
|
bp->b_blkno = blk;
|
|
|
|
VM_OBJECT_WLOCK(object);
|
|
for (j = 0; j < n; ++j) {
|
|
mreq = ma[i + j];
|
|
addr = swp_pager_meta_build(mreq->object, mreq->pindex,
|
|
blk + j);
|
|
if (addr != SWAPBLK_NONE)
|
|
swp_pager_update_freerange(&s_free, &n_free,
|
|
addr);
|
|
MPASS(mreq->dirty == VM_PAGE_BITS_ALL);
|
|
mreq->oflags |= VPO_SWAPINPROG;
|
|
bp->b_pages[j] = mreq;
|
|
}
|
|
VM_OBJECT_WUNLOCK(object);
|
|
bp->b_npages = n;
|
|
/*
|
|
* Must set dirty range for NFS to work.
|
|
*/
|
|
bp->b_dirtyoff = 0;
|
|
bp->b_dirtyend = bp->b_bcount;
|
|
|
|
VM_CNT_INC(v_swapout);
|
|
VM_CNT_ADD(v_swappgsout, bp->b_npages);
|
|
|
|
/*
|
|
* We unconditionally set rtvals[] to VM_PAGER_PEND so that we
|
|
* can call the async completion routine at the end of a
|
|
* synchronous I/O operation. Otherwise, our caller would
|
|
* perform duplicate unbusy and wakeup operations on the page
|
|
* and object, respectively.
|
|
*/
|
|
for (j = 0; j < n; j++)
|
|
rtvals[i + j] = VM_PAGER_PEND;
|
|
|
|
/*
|
|
* asynchronous
|
|
*
|
|
* NOTE: b_blkno is destroyed by the call to swapdev_strategy.
|
|
*/
|
|
if (async) {
|
|
bp->b_iodone = swp_pager_async_iodone;
|
|
BUF_KERNPROC(bp);
|
|
swp_pager_strategy(bp);
|
|
continue;
|
|
}
|
|
|
|
/*
|
|
* synchronous
|
|
*
|
|
* NOTE: b_blkno is destroyed by the call to swapdev_strategy.
|
|
*/
|
|
bp->b_iodone = bdone;
|
|
swp_pager_strategy(bp);
|
|
|
|
/*
|
|
* Wait for the sync I/O to complete.
|
|
*/
|
|
bwait(bp, PVM, "swwrt");
|
|
|
|
/*
|
|
* Now that we are through with the bp, we can call the
|
|
* normal async completion, which frees everything up.
|
|
*/
|
|
swp_pager_async_iodone(bp);
|
|
}
|
|
swp_pager_freeswapspace(s_free, n_free);
|
|
VM_OBJECT_WLOCK(object);
|
|
}
|
|
|
|
/*
|
|
* swp_pager_async_iodone:
|
|
*
|
|
* Completion routine for asynchronous reads and writes from/to swap.
|
|
* Also called manually by synchronous code to finish up a bp.
|
|
*
|
|
* This routine may not sleep.
|
|
*/
|
|
static void
|
|
swp_pager_async_iodone(struct buf *bp)
|
|
{
|
|
int i;
|
|
vm_object_t object = NULL;
|
|
|
|
/*
|
|
* Report error - unless we ran out of memory, in which case
|
|
* we've already logged it in swapgeom_strategy().
|
|
*/
|
|
if (bp->b_ioflags & BIO_ERROR && bp->b_error != ENOMEM) {
|
|
printf(
|
|
"swap_pager: I/O error - %s failed; blkno %ld,"
|
|
"size %ld, error %d\n",
|
|
((bp->b_iocmd == BIO_READ) ? "pagein" : "pageout"),
|
|
(long)bp->b_blkno,
|
|
(long)bp->b_bcount,
|
|
bp->b_error
|
|
);
|
|
}
|
|
|
|
/*
|
|
* remove the mapping for kernel virtual
|
|
*/
|
|
if (buf_mapped(bp))
|
|
pmap_qremove((vm_offset_t)bp->b_data, bp->b_npages);
|
|
else
|
|
bp->b_data = bp->b_kvabase;
|
|
|
|
if (bp->b_npages) {
|
|
object = bp->b_pages[0]->object;
|
|
VM_OBJECT_WLOCK(object);
|
|
}
|
|
|
|
/*
|
|
* cleanup pages. If an error occurs writing to swap, we are in
|
|
* very serious trouble. If it happens to be a disk error, though,
|
|
* we may be able to recover by reassigning the swap later on. So
|
|
* in this case we remove the m->swapblk assignment for the page
|
|
* but do not free it in the rlist. The errornous block(s) are thus
|
|
* never reallocated as swap. Redirty the page and continue.
|
|
*/
|
|
for (i = 0; i < bp->b_npages; ++i) {
|
|
vm_page_t m = bp->b_pages[i];
|
|
|
|
m->oflags &= ~VPO_SWAPINPROG;
|
|
if (m->oflags & VPO_SWAPSLEEP) {
|
|
m->oflags &= ~VPO_SWAPSLEEP;
|
|
wakeup(&object->handle);
|
|
}
|
|
|
|
if (bp->b_ioflags & BIO_ERROR) {
|
|
/*
|
|
* If an error occurs I'd love to throw the swapblk
|
|
* away without freeing it back to swapspace, so it
|
|
* can never be used again. But I can't from an
|
|
* interrupt.
|
|
*/
|
|
if (bp->b_iocmd == BIO_READ) {
|
|
/*
|
|
* NOTE: for reads, m->dirty will probably
|
|
* be overridden by the original caller of
|
|
* getpages so don't play cute tricks here.
|
|
*/
|
|
vm_page_invalid(m);
|
|
} else {
|
|
/*
|
|
* If a write error occurs, reactivate page
|
|
* so it doesn't clog the inactive list,
|
|
* then finish the I/O.
|
|
*/
|
|
MPASS(m->dirty == VM_PAGE_BITS_ALL);
|
|
vm_page_lock(m);
|
|
vm_page_activate(m);
|
|
vm_page_unlock(m);
|
|
vm_page_sunbusy(m);
|
|
}
|
|
} else if (bp->b_iocmd == BIO_READ) {
|
|
/*
|
|
* NOTE: for reads, m->dirty will probably be
|
|
* overridden by the original caller of getpages so
|
|
* we cannot set them in order to free the underlying
|
|
* swap in a low-swap situation. I don't think we'd
|
|
* want to do that anyway, but it was an optimization
|
|
* that existed in the old swapper for a time before
|
|
* it got ripped out due to precisely this problem.
|
|
*/
|
|
KASSERT(!pmap_page_is_mapped(m),
|
|
("swp_pager_async_iodone: page %p is mapped", m));
|
|
KASSERT(m->dirty == 0,
|
|
("swp_pager_async_iodone: page %p is dirty", m));
|
|
|
|
vm_page_valid(m);
|
|
if (i < bp->b_pgbefore ||
|
|
i >= bp->b_npages - bp->b_pgafter)
|
|
vm_page_readahead_finish(m);
|
|
} else {
|
|
/*
|
|
* For write success, clear the dirty
|
|
* status, then finish the I/O ( which decrements the
|
|
* busy count and possibly wakes waiter's up ).
|
|
* A page is only written to swap after a period of
|
|
* inactivity. Therefore, we do not expect it to be
|
|
* reused.
|
|
*/
|
|
KASSERT(!pmap_page_is_write_mapped(m),
|
|
("swp_pager_async_iodone: page %p is not write"
|
|
" protected", m));
|
|
vm_page_undirty(m);
|
|
vm_page_lock(m);
|
|
vm_page_deactivate_noreuse(m);
|
|
vm_page_unlock(m);
|
|
vm_page_sunbusy(m);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* adjust pip. NOTE: the original parent may still have its own
|
|
* pip refs on the object.
|
|
*/
|
|
if (object != NULL) {
|
|
vm_object_pip_wakeupn(object, bp->b_npages);
|
|
VM_OBJECT_WUNLOCK(object);
|
|
}
|
|
|
|
/*
|
|
* swapdev_strategy() manually sets b_vp and b_bufobj before calling
|
|
* bstrategy(). Set them back to NULL now we're done with it, or we'll
|
|
* trigger a KASSERT in relpbuf().
|
|
*/
|
|
if (bp->b_vp) {
|
|
bp->b_vp = NULL;
|
|
bp->b_bufobj = NULL;
|
|
}
|
|
/*
|
|
* release the physical I/O buffer
|
|
*/
|
|
if (bp->b_flags & B_ASYNC) {
|
|
mtx_lock(&swbuf_mtx);
|
|
if (++nsw_wcount_async == 1)
|
|
wakeup(&nsw_wcount_async);
|
|
mtx_unlock(&swbuf_mtx);
|
|
}
|
|
uma_zfree((bp->b_iocmd == BIO_READ) ? swrbuf_zone : swwbuf_zone, bp);
|
|
}
|
|
|
|
int
|
|
swap_pager_nswapdev(void)
|
|
{
|
|
|
|
return (nswapdev);
|
|
}
|
|
|
|
static void
|
|
swp_pager_force_dirty(vm_page_t m)
|
|
{
|
|
|
|
vm_page_dirty(m);
|
|
#ifdef INVARIANTS
|
|
vm_page_lock(m);
|
|
if (!vm_page_wired(m) && m->queue == PQ_NONE)
|
|
panic("page %p is neither wired nor queued", m);
|
|
vm_page_unlock(m);
|
|
#endif
|
|
vm_page_xunbusy(m);
|
|
swap_pager_unswapped(m);
|
|
}
|
|
|
|
static void
|
|
swp_pager_force_launder(vm_page_t m)
|
|
{
|
|
|
|
vm_page_dirty(m);
|
|
vm_page_lock(m);
|
|
vm_page_launder(m);
|
|
vm_page_unlock(m);
|
|
vm_page_xunbusy(m);
|
|
swap_pager_unswapped(m);
|
|
}
|
|
|
|
/*
|
|
* SWP_PAGER_FORCE_PAGEIN() - force swap blocks to be paged in
|
|
*
|
|
* This routine dissociates pages starting at the given index within an
|
|
* object from their backing store, paging them in if they do not reside
|
|
* in memory. Pages that are paged in are marked dirty and placed in the
|
|
* laundry queue. Pages are marked dirty because they no longer have
|
|
* backing store. They are placed in the laundry queue because they have
|
|
* not been accessed recently. Otherwise, they would already reside in
|
|
* memory.
|
|
*/
|
|
static void
|
|
swp_pager_force_pagein(vm_object_t object, vm_pindex_t pindex, int npages)
|
|
{
|
|
vm_page_t ma[npages];
|
|
int i, j;
|
|
|
|
KASSERT(npages > 0, ("%s: No pages", __func__));
|
|
KASSERT(npages <= MAXPHYS / PAGE_SIZE,
|
|
("%s: Too many pages: %d", __func__, npages));
|
|
vm_object_pip_add(object, npages);
|
|
vm_page_grab_pages(object, pindex, VM_ALLOC_NORMAL, ma, npages);
|
|
for (i = j = 0;; i++) {
|
|
/* Count nonresident pages, to page-in all at once. */
|
|
if (i < npages && ma[i]->valid != VM_PAGE_BITS_ALL)
|
|
continue;
|
|
if (j < i) {
|
|
/* Page-in nonresident pages. Mark for laundering. */
|
|
if (swap_pager_getpages(object, &ma[j], i - j, NULL,
|
|
NULL) != VM_PAGER_OK)
|
|
panic("%s: read from swap failed", __func__);
|
|
do {
|
|
swp_pager_force_launder(ma[j]);
|
|
} while (++j < i);
|
|
}
|
|
if (i == npages)
|
|
break;
|
|
/* Mark dirty a resident page. */
|
|
swp_pager_force_dirty(ma[j++]);
|
|
}
|
|
vm_object_pip_wakeupn(object, npages);
|
|
}
|
|
|
|
/*
|
|
* swap_pager_swapoff_object:
|
|
*
|
|
* Page in all of the pages that have been paged out for an object
|
|
* to a swap device.
|
|
*/
|
|
static void
|
|
swap_pager_swapoff_object(struct swdevt *sp, vm_object_t object)
|
|
{
|
|
struct swblk *sb;
|
|
vm_pindex_t pi, s_pindex;
|
|
daddr_t blk, n_blks, s_blk;
|
|
int i;
|
|
|
|
n_blks = 0;
|
|
for (pi = 0; (sb = SWAP_PCTRIE_LOOKUP_GE(
|
|
&object->un_pager.swp.swp_blks, pi)) != NULL; ) {
|
|
for (i = 0; i < SWAP_META_PAGES; i++) {
|
|
blk = sb->d[i];
|
|
if (!swp_pager_isondev(blk, sp))
|
|
blk = SWAPBLK_NONE;
|
|
|
|
/*
|
|
* If there are no blocks/pages accumulated, start a new
|
|
* accumulation here.
|
|
*/
|
|
if (n_blks == 0) {
|
|
if (blk != SWAPBLK_NONE) {
|
|
s_blk = blk;
|
|
s_pindex = sb->p + i;
|
|
n_blks = 1;
|
|
}
|
|
continue;
|
|
}
|
|
|
|
/*
|
|
* If the accumulation can be extended without breaking
|
|
* the sequence of consecutive blocks and pages that
|
|
* swp_pager_force_pagein() depends on, do so.
|
|
*/
|
|
if (n_blks < MAXPHYS / PAGE_SIZE &&
|
|
s_blk + n_blks == blk &&
|
|
s_pindex + n_blks == sb->p + i) {
|
|
++n_blks;
|
|
continue;
|
|
}
|
|
|
|
/*
|
|
* The sequence of consecutive blocks and pages cannot
|
|
* be extended, so page them all in here. Then,
|
|
* because doing so involves releasing and reacquiring
|
|
* a lock that protects the swap block pctrie, do not
|
|
* rely on the current swap block. Break this loop and
|
|
* re-fetch the same pindex from the pctrie again.
|
|
*/
|
|
swp_pager_force_pagein(object, s_pindex, n_blks);
|
|
n_blks = 0;
|
|
break;
|
|
}
|
|
if (i == SWAP_META_PAGES)
|
|
pi = sb->p + SWAP_META_PAGES;
|
|
}
|
|
if (n_blks > 0)
|
|
swp_pager_force_pagein(object, s_pindex, n_blks);
|
|
}
|
|
|
|
/*
|
|
* swap_pager_swapoff:
|
|
*
|
|
* Page in all of the pages that have been paged out to the
|
|
* given device. The corresponding blocks in the bitmap must be
|
|
* marked as allocated and the device must be flagged SW_CLOSING.
|
|
* There may be no processes swapped out to the device.
|
|
*
|
|
* This routine may block.
|
|
*/
|
|
static void
|
|
swap_pager_swapoff(struct swdevt *sp)
|
|
{
|
|
vm_object_t object;
|
|
int retries;
|
|
|
|
sx_assert(&swdev_syscall_lock, SA_XLOCKED);
|
|
|
|
retries = 0;
|
|
full_rescan:
|
|
mtx_lock(&vm_object_list_mtx);
|
|
TAILQ_FOREACH(object, &vm_object_list, object_list) {
|
|
if (object->type != OBJT_SWAP)
|
|
continue;
|
|
mtx_unlock(&vm_object_list_mtx);
|
|
/* Depends on type-stability. */
|
|
VM_OBJECT_WLOCK(object);
|
|
|
|
/*
|
|
* Dead objects are eventually terminated on their own.
|
|
*/
|
|
if ((object->flags & OBJ_DEAD) != 0)
|
|
goto next_obj;
|
|
|
|
/*
|
|
* Sync with fences placed after pctrie
|
|
* initialization. We must not access pctrie below
|
|
* unless we checked that our object is swap and not
|
|
* dead.
|
|
*/
|
|
atomic_thread_fence_acq();
|
|
if (object->type != OBJT_SWAP)
|
|
goto next_obj;
|
|
|
|
swap_pager_swapoff_object(sp, object);
|
|
next_obj:
|
|
VM_OBJECT_WUNLOCK(object);
|
|
mtx_lock(&vm_object_list_mtx);
|
|
}
|
|
mtx_unlock(&vm_object_list_mtx);
|
|
|
|
if (sp->sw_used) {
|
|
/*
|
|
* Objects may be locked or paging to the device being
|
|
* removed, so we will miss their pages and need to
|
|
* make another pass. We have marked this device as
|
|
* SW_CLOSING, so the activity should finish soon.
|
|
*/
|
|
retries++;
|
|
if (retries > 100) {
|
|
panic("swapoff: failed to locate %d swap blocks",
|
|
sp->sw_used);
|
|
}
|
|
pause("swpoff", hz / 20);
|
|
goto full_rescan;
|
|
}
|
|
EVENTHANDLER_INVOKE(swapoff, sp);
|
|
}
|
|
|
|
/************************************************************************
|
|
* SWAP META DATA *
|
|
************************************************************************
|
|
*
|
|
* These routines manipulate the swap metadata stored in the
|
|
* OBJT_SWAP object.
|
|
*
|
|
* Swap metadata is implemented with a global hash and not directly
|
|
* linked into the object. Instead the object simply contains
|
|
* appropriate tracking counters.
|
|
*/
|
|
|
|
/*
|
|
* SWP_PAGER_SWBLK_EMPTY() - is a range of blocks free?
|
|
*/
|
|
static bool
|
|
swp_pager_swblk_empty(struct swblk *sb, int start, int limit)
|
|
{
|
|
int i;
|
|
|
|
MPASS(0 <= start && start <= limit && limit <= SWAP_META_PAGES);
|
|
for (i = start; i < limit; i++) {
|
|
if (sb->d[i] != SWAPBLK_NONE)
|
|
return (false);
|
|
}
|
|
return (true);
|
|
}
|
|
|
|
/*
|
|
* SWP_PAGER_META_BUILD() - add swap block to swap meta data for object
|
|
*
|
|
* We first convert the object to a swap object if it is a default
|
|
* object.
|
|
*
|
|
* The specified swapblk is added to the object's swap metadata. If
|
|
* the swapblk is not valid, it is freed instead. Any previously
|
|
* assigned swapblk is returned.
|
|
*/
|
|
static daddr_t
|
|
swp_pager_meta_build(vm_object_t object, vm_pindex_t pindex, daddr_t swapblk)
|
|
{
|
|
static volatile int swblk_zone_exhausted, swpctrie_zone_exhausted;
|
|
struct swblk *sb, *sb1;
|
|
vm_pindex_t modpi, rdpi;
|
|
daddr_t prev_swapblk;
|
|
int error, i;
|
|
|
|
VM_OBJECT_ASSERT_WLOCKED(object);
|
|
|
|
/*
|
|
* Convert default object to swap object if necessary
|
|
*/
|
|
if (object->type != OBJT_SWAP) {
|
|
pctrie_init(&object->un_pager.swp.swp_blks);
|
|
|
|
/*
|
|
* Ensure that swap_pager_swapoff()'s iteration over
|
|
* object_list does not see a garbage pctrie.
|
|
*/
|
|
atomic_thread_fence_rel();
|
|
|
|
object->type = OBJT_SWAP;
|
|
object->un_pager.swp.writemappings = 0;
|
|
KASSERT(object->handle == NULL, ("default pager with handle"));
|
|
}
|
|
|
|
rdpi = rounddown(pindex, SWAP_META_PAGES);
|
|
sb = SWAP_PCTRIE_LOOKUP(&object->un_pager.swp.swp_blks, rdpi);
|
|
if (sb == NULL) {
|
|
if (swapblk == SWAPBLK_NONE)
|
|
return (SWAPBLK_NONE);
|
|
for (;;) {
|
|
sb = uma_zalloc(swblk_zone, M_NOWAIT | (curproc ==
|
|
pageproc ? M_USE_RESERVE : 0));
|
|
if (sb != NULL) {
|
|
sb->p = rdpi;
|
|
for (i = 0; i < SWAP_META_PAGES; i++)
|
|
sb->d[i] = SWAPBLK_NONE;
|
|
if (atomic_cmpset_int(&swblk_zone_exhausted,
|
|
1, 0))
|
|
printf("swblk zone ok\n");
|
|
break;
|
|
}
|
|
VM_OBJECT_WUNLOCK(object);
|
|
if (uma_zone_exhausted(swblk_zone)) {
|
|
if (atomic_cmpset_int(&swblk_zone_exhausted,
|
|
0, 1))
|
|
printf("swap blk zone exhausted, "
|
|
"increase kern.maxswzone\n");
|
|
vm_pageout_oom(VM_OOM_SWAPZ);
|
|
pause("swzonxb", 10);
|
|
} else
|
|
uma_zwait(swblk_zone);
|
|
VM_OBJECT_WLOCK(object);
|
|
sb = SWAP_PCTRIE_LOOKUP(&object->un_pager.swp.swp_blks,
|
|
rdpi);
|
|
if (sb != NULL)
|
|
/*
|
|
* Somebody swapped out a nearby page,
|
|
* allocating swblk at the rdpi index,
|
|
* while we dropped the object lock.
|
|
*/
|
|
goto allocated;
|
|
}
|
|
for (;;) {
|
|
error = SWAP_PCTRIE_INSERT(
|
|
&object->un_pager.swp.swp_blks, sb);
|
|
if (error == 0) {
|
|
if (atomic_cmpset_int(&swpctrie_zone_exhausted,
|
|
1, 0))
|
|
printf("swpctrie zone ok\n");
|
|
break;
|
|
}
|
|
VM_OBJECT_WUNLOCK(object);
|
|
if (uma_zone_exhausted(swpctrie_zone)) {
|
|
if (atomic_cmpset_int(&swpctrie_zone_exhausted,
|
|
0, 1))
|
|
printf("swap pctrie zone exhausted, "
|
|
"increase kern.maxswzone\n");
|
|
vm_pageout_oom(VM_OOM_SWAPZ);
|
|
pause("swzonxp", 10);
|
|
} else
|
|
uma_zwait(swpctrie_zone);
|
|
VM_OBJECT_WLOCK(object);
|
|
sb1 = SWAP_PCTRIE_LOOKUP(&object->un_pager.swp.swp_blks,
|
|
rdpi);
|
|
if (sb1 != NULL) {
|
|
uma_zfree(swblk_zone, sb);
|
|
sb = sb1;
|
|
goto allocated;
|
|
}
|
|
}
|
|
}
|
|
allocated:
|
|
MPASS(sb->p == rdpi);
|
|
|
|
modpi = pindex % SWAP_META_PAGES;
|
|
/* Return prior contents of metadata. */
|
|
prev_swapblk = sb->d[modpi];
|
|
/* Enter block into metadata. */
|
|
sb->d[modpi] = swapblk;
|
|
|
|
/*
|
|
* Free the swblk if we end up with the empty page run.
|
|
*/
|
|
if (swapblk == SWAPBLK_NONE &&
|
|
swp_pager_swblk_empty(sb, 0, SWAP_META_PAGES)) {
|
|
SWAP_PCTRIE_REMOVE(&object->un_pager.swp.swp_blks, rdpi);
|
|
uma_zfree(swblk_zone, sb);
|
|
}
|
|
return (prev_swapblk);
|
|
}
|
|
|
|
/*
|
|
* SWP_PAGER_META_FREE() - free a range of blocks in the object's swap metadata
|
|
*
|
|
* The requested range of blocks is freed, with any associated swap
|
|
* returned to the swap bitmap.
|
|
*
|
|
* This routine will free swap metadata structures as they are cleaned
|
|
* out. This routine does *NOT* operate on swap metadata associated
|
|
* with resident pages.
|
|
*/
|
|
static void
|
|
swp_pager_meta_free(vm_object_t object, vm_pindex_t pindex, vm_pindex_t count)
|
|
{
|
|
struct swblk *sb;
|
|
daddr_t n_free, s_free;
|
|
vm_pindex_t last;
|
|
int i, limit, start;
|
|
|
|
VM_OBJECT_ASSERT_WLOCKED(object);
|
|
if (object->type != OBJT_SWAP || count == 0)
|
|
return;
|
|
|
|
swp_pager_init_freerange(&s_free, &n_free);
|
|
last = pindex + count;
|
|
for (;;) {
|
|
sb = SWAP_PCTRIE_LOOKUP_GE(&object->un_pager.swp.swp_blks,
|
|
rounddown(pindex, SWAP_META_PAGES));
|
|
if (sb == NULL || sb->p >= last)
|
|
break;
|
|
start = pindex > sb->p ? pindex - sb->p : 0;
|
|
limit = last - sb->p < SWAP_META_PAGES ? last - sb->p :
|
|
SWAP_META_PAGES;
|
|
for (i = start; i < limit; i++) {
|
|
if (sb->d[i] == SWAPBLK_NONE)
|
|
continue;
|
|
swp_pager_update_freerange(&s_free, &n_free, sb->d[i]);
|
|
sb->d[i] = SWAPBLK_NONE;
|
|
}
|
|
pindex = sb->p + SWAP_META_PAGES;
|
|
if (swp_pager_swblk_empty(sb, 0, start) &&
|
|
swp_pager_swblk_empty(sb, limit, SWAP_META_PAGES)) {
|
|
SWAP_PCTRIE_REMOVE(&object->un_pager.swp.swp_blks,
|
|
sb->p);
|
|
uma_zfree(swblk_zone, sb);
|
|
}
|
|
}
|
|
swp_pager_freeswapspace(s_free, n_free);
|
|
}
|
|
|
|
/*
|
|
* SWP_PAGER_META_FREE_ALL() - destroy all swap metadata associated with object
|
|
*
|
|
* This routine locates and destroys all swap metadata associated with
|
|
* an object.
|
|
*/
|
|
static void
|
|
swp_pager_meta_free_all(vm_object_t object)
|
|
{
|
|
struct swblk *sb;
|
|
daddr_t n_free, s_free;
|
|
vm_pindex_t pindex;
|
|
int i;
|
|
|
|
VM_OBJECT_ASSERT_WLOCKED(object);
|
|
if (object->type != OBJT_SWAP)
|
|
return;
|
|
|
|
swp_pager_init_freerange(&s_free, &n_free);
|
|
for (pindex = 0; (sb = SWAP_PCTRIE_LOOKUP_GE(
|
|
&object->un_pager.swp.swp_blks, pindex)) != NULL;) {
|
|
pindex = sb->p + SWAP_META_PAGES;
|
|
for (i = 0; i < SWAP_META_PAGES; i++) {
|
|
if (sb->d[i] == SWAPBLK_NONE)
|
|
continue;
|
|
swp_pager_update_freerange(&s_free, &n_free, sb->d[i]);
|
|
}
|
|
SWAP_PCTRIE_REMOVE(&object->un_pager.swp.swp_blks, sb->p);
|
|
uma_zfree(swblk_zone, sb);
|
|
}
|
|
swp_pager_freeswapspace(s_free, n_free);
|
|
}
|
|
|
|
/*
|
|
* SWP_PAGER_METACTL() - misc control of swap meta data.
|
|
*
|
|
* This routine is capable of looking up, or removing swapblk
|
|
* assignments in the swap meta data. It returns the swapblk being
|
|
* looked-up, popped, or SWAPBLK_NONE if the block was invalid.
|
|
*
|
|
* When acting on a busy resident page and paging is in progress, we
|
|
* have to wait until paging is complete but otherwise can act on the
|
|
* busy page.
|
|
*
|
|
* SWM_POP remove from meta data but do not free it
|
|
*/
|
|
static daddr_t
|
|
swp_pager_meta_ctl(vm_object_t object, vm_pindex_t pindex, int flags)
|
|
{
|
|
struct swblk *sb;
|
|
daddr_t r1;
|
|
|
|
if ((flags & SWM_POP) != 0)
|
|
VM_OBJECT_ASSERT_WLOCKED(object);
|
|
else
|
|
VM_OBJECT_ASSERT_LOCKED(object);
|
|
|
|
/*
|
|
* The meta data only exists if the object is OBJT_SWAP
|
|
* and even then might not be allocated yet.
|
|
*/
|
|
if (object->type != OBJT_SWAP)
|
|
return (SWAPBLK_NONE);
|
|
|
|
sb = SWAP_PCTRIE_LOOKUP(&object->un_pager.swp.swp_blks,
|
|
rounddown(pindex, SWAP_META_PAGES));
|
|
if (sb == NULL)
|
|
return (SWAPBLK_NONE);
|
|
r1 = sb->d[pindex % SWAP_META_PAGES];
|
|
if (r1 == SWAPBLK_NONE)
|
|
return (SWAPBLK_NONE);
|
|
if ((flags & SWM_POP) != 0) {
|
|
sb->d[pindex % SWAP_META_PAGES] = SWAPBLK_NONE;
|
|
if (swp_pager_swblk_empty(sb, 0, SWAP_META_PAGES)) {
|
|
SWAP_PCTRIE_REMOVE(&object->un_pager.swp.swp_blks,
|
|
rounddown(pindex, SWAP_META_PAGES));
|
|
uma_zfree(swblk_zone, sb);
|
|
}
|
|
}
|
|
return (r1);
|
|
}
|
|
|
|
/*
|
|
* Returns the least page index which is greater than or equal to the
|
|
* parameter pindex and for which there is a swap block allocated.
|
|
* Returns object's size if the object's type is not swap or if there
|
|
* are no allocated swap blocks for the object after the requested
|
|
* pindex.
|
|
*/
|
|
vm_pindex_t
|
|
swap_pager_find_least(vm_object_t object, vm_pindex_t pindex)
|
|
{
|
|
struct swblk *sb;
|
|
int i;
|
|
|
|
VM_OBJECT_ASSERT_LOCKED(object);
|
|
if (object->type != OBJT_SWAP)
|
|
return (object->size);
|
|
|
|
sb = SWAP_PCTRIE_LOOKUP_GE(&object->un_pager.swp.swp_blks,
|
|
rounddown(pindex, SWAP_META_PAGES));
|
|
if (sb == NULL)
|
|
return (object->size);
|
|
if (sb->p < pindex) {
|
|
for (i = pindex % SWAP_META_PAGES; i < SWAP_META_PAGES; i++) {
|
|
if (sb->d[i] != SWAPBLK_NONE)
|
|
return (sb->p + i);
|
|
}
|
|
sb = SWAP_PCTRIE_LOOKUP_GE(&object->un_pager.swp.swp_blks,
|
|
roundup(pindex, SWAP_META_PAGES));
|
|
if (sb == NULL)
|
|
return (object->size);
|
|
}
|
|
for (i = 0; i < SWAP_META_PAGES; i++) {
|
|
if (sb->d[i] != SWAPBLK_NONE)
|
|
return (sb->p + i);
|
|
}
|
|
|
|
/*
|
|
* We get here if a swblk is present in the trie but it
|
|
* doesn't map any blocks.
|
|
*/
|
|
MPASS(0);
|
|
return (object->size);
|
|
}
|
|
|
|
/*
|
|
* System call swapon(name) enables swapping on device name,
|
|
* which must be in the swdevsw. Return EBUSY
|
|
* if already swapping on this device.
|
|
*/
|
|
#ifndef _SYS_SYSPROTO_H_
|
|
struct swapon_args {
|
|
char *name;
|
|
};
|
|
#endif
|
|
|
|
/*
|
|
* MPSAFE
|
|
*/
|
|
/* ARGSUSED */
|
|
int
|
|
sys_swapon(struct thread *td, struct swapon_args *uap)
|
|
{
|
|
struct vattr attr;
|
|
struct vnode *vp;
|
|
struct nameidata nd;
|
|
int error;
|
|
|
|
error = priv_check(td, PRIV_SWAPON);
|
|
if (error)
|
|
return (error);
|
|
|
|
sx_xlock(&swdev_syscall_lock);
|
|
|
|
/*
|
|
* Swap metadata may not fit in the KVM if we have physical
|
|
* memory of >1GB.
|
|
*/
|
|
if (swblk_zone == NULL) {
|
|
error = ENOMEM;
|
|
goto done;
|
|
}
|
|
|
|
NDINIT(&nd, LOOKUP, ISOPEN | FOLLOW | AUDITVNODE1, UIO_USERSPACE,
|
|
uap->name, td);
|
|
error = namei(&nd);
|
|
if (error)
|
|
goto done;
|
|
|
|
NDFREE(&nd, NDF_ONLY_PNBUF);
|
|
vp = nd.ni_vp;
|
|
|
|
if (vn_isdisk(vp, &error)) {
|
|
error = swapongeom(vp);
|
|
} else if (vp->v_type == VREG &&
|
|
(vp->v_mount->mnt_vfc->vfc_flags & VFCF_NETWORK) != 0 &&
|
|
(error = VOP_GETATTR(vp, &attr, td->td_ucred)) == 0) {
|
|
/*
|
|
* Allow direct swapping to NFS regular files in the same
|
|
* way that nfs_mountroot() sets up diskless swapping.
|
|
*/
|
|
error = swaponvp(td, vp, attr.va_size / DEV_BSIZE);
|
|
}
|
|
|
|
if (error)
|
|
vrele(vp);
|
|
done:
|
|
sx_xunlock(&swdev_syscall_lock);
|
|
return (error);
|
|
}
|
|
|
|
/*
|
|
* Check that the total amount of swap currently configured does not
|
|
* exceed half the theoretical maximum. If it does, print a warning
|
|
* message.
|
|
*/
|
|
static void
|
|
swapon_check_swzone(void)
|
|
{
|
|
|
|
/* recommend using no more than half that amount */
|
|
if (swap_total > swap_maxpages / 2) {
|
|
printf("warning: total configured swap (%lu pages) "
|
|
"exceeds maximum recommended amount (%lu pages).\n",
|
|
swap_total, swap_maxpages / 2);
|
|
printf("warning: increase kern.maxswzone "
|
|
"or reduce amount of swap.\n");
|
|
}
|
|
}
|
|
|
|
static void
|
|
swaponsomething(struct vnode *vp, void *id, u_long nblks,
|
|
sw_strategy_t *strategy, sw_close_t *close, dev_t dev, int flags)
|
|
{
|
|
struct swdevt *sp, *tsp;
|
|
swblk_t dvbase;
|
|
u_long mblocks;
|
|
|
|
/*
|
|
* nblks is in DEV_BSIZE'd chunks, convert to PAGE_SIZE'd chunks.
|
|
* First chop nblks off to page-align it, then convert.
|
|
*
|
|
* sw->sw_nblks is in page-sized chunks now too.
|
|
*/
|
|
nblks &= ~(ctodb(1) - 1);
|
|
nblks = dbtoc(nblks);
|
|
|
|
/*
|
|
* If we go beyond this, we get overflows in the radix
|
|
* tree bitmap code.
|
|
*/
|
|
mblocks = 0x40000000 / BLIST_META_RADIX;
|
|
if (nblks > mblocks) {
|
|
printf(
|
|
"WARNING: reducing swap size to maximum of %luMB per unit\n",
|
|
mblocks / 1024 / 1024 * PAGE_SIZE);
|
|
nblks = mblocks;
|
|
}
|
|
|
|
sp = malloc(sizeof *sp, M_VMPGDATA, M_WAITOK | M_ZERO);
|
|
sp->sw_vp = vp;
|
|
sp->sw_id = id;
|
|
sp->sw_dev = dev;
|
|
sp->sw_nblks = nblks;
|
|
sp->sw_used = 0;
|
|
sp->sw_strategy = strategy;
|
|
sp->sw_close = close;
|
|
sp->sw_flags = flags;
|
|
|
|
sp->sw_blist = blist_create(nblks, M_WAITOK);
|
|
/*
|
|
* Do not free the first blocks in order to avoid overwriting
|
|
* any bsd label at the front of the partition
|
|
*/
|
|
blist_free(sp->sw_blist, howmany(BBSIZE, PAGE_SIZE),
|
|
nblks - howmany(BBSIZE, PAGE_SIZE));
|
|
|
|
dvbase = 0;
|
|
mtx_lock(&sw_dev_mtx);
|
|
TAILQ_FOREACH(tsp, &swtailq, sw_list) {
|
|
if (tsp->sw_end >= dvbase) {
|
|
/*
|
|
* We put one uncovered page between the devices
|
|
* in order to definitively prevent any cross-device
|
|
* I/O requests
|
|
*/
|
|
dvbase = tsp->sw_end + 1;
|
|
}
|
|
}
|
|
sp->sw_first = dvbase;
|
|
sp->sw_end = dvbase + nblks;
|
|
TAILQ_INSERT_TAIL(&swtailq, sp, sw_list);
|
|
nswapdev++;
|
|
swap_pager_avail += nblks - howmany(BBSIZE, PAGE_SIZE);
|
|
swap_total += nblks;
|
|
swapon_check_swzone();
|
|
swp_sizecheck();
|
|
mtx_unlock(&sw_dev_mtx);
|
|
EVENTHANDLER_INVOKE(swapon, sp);
|
|
}
|
|
|
|
/*
|
|
* SYSCALL: swapoff(devname)
|
|
*
|
|
* Disable swapping on the given device.
|
|
*
|
|
* XXX: Badly designed system call: it should use a device index
|
|
* rather than filename as specification. We keep sw_vp around
|
|
* only to make this work.
|
|
*/
|
|
#ifndef _SYS_SYSPROTO_H_
|
|
struct swapoff_args {
|
|
char *name;
|
|
};
|
|
#endif
|
|
|
|
/*
|
|
* MPSAFE
|
|
*/
|
|
/* ARGSUSED */
|
|
int
|
|
sys_swapoff(struct thread *td, struct swapoff_args *uap)
|
|
{
|
|
struct vnode *vp;
|
|
struct nameidata nd;
|
|
struct swdevt *sp;
|
|
int error;
|
|
|
|
error = priv_check(td, PRIV_SWAPOFF);
|
|
if (error)
|
|
return (error);
|
|
|
|
sx_xlock(&swdev_syscall_lock);
|
|
|
|
NDINIT(&nd, LOOKUP, FOLLOW | AUDITVNODE1, UIO_USERSPACE, uap->name,
|
|
td);
|
|
error = namei(&nd);
|
|
if (error)
|
|
goto done;
|
|
NDFREE(&nd, NDF_ONLY_PNBUF);
|
|
vp = nd.ni_vp;
|
|
|
|
mtx_lock(&sw_dev_mtx);
|
|
TAILQ_FOREACH(sp, &swtailq, sw_list) {
|
|
if (sp->sw_vp == vp)
|
|
break;
|
|
}
|
|
mtx_unlock(&sw_dev_mtx);
|
|
if (sp == NULL) {
|
|
error = EINVAL;
|
|
goto done;
|
|
}
|
|
error = swapoff_one(sp, td->td_ucred);
|
|
done:
|
|
sx_xunlock(&swdev_syscall_lock);
|
|
return (error);
|
|
}
|
|
|
|
static int
|
|
swapoff_one(struct swdevt *sp, struct ucred *cred)
|
|
{
|
|
u_long nblks;
|
|
#ifdef MAC
|
|
int error;
|
|
#endif
|
|
|
|
sx_assert(&swdev_syscall_lock, SA_XLOCKED);
|
|
#ifdef MAC
|
|
(void) vn_lock(sp->sw_vp, LK_EXCLUSIVE | LK_RETRY);
|
|
error = mac_system_check_swapoff(cred, sp->sw_vp);
|
|
(void) VOP_UNLOCK(sp->sw_vp, 0);
|
|
if (error != 0)
|
|
return (error);
|
|
#endif
|
|
nblks = sp->sw_nblks;
|
|
|
|
/*
|
|
* We can turn off this swap device safely only if the
|
|
* available virtual memory in the system will fit the amount
|
|
* of data we will have to page back in, plus an epsilon so
|
|
* the system doesn't become critically low on swap space.
|
|
*/
|
|
if (vm_free_count() + swap_pager_avail < nblks + nswap_lowat)
|
|
return (ENOMEM);
|
|
|
|
/*
|
|
* Prevent further allocations on this device.
|
|
*/
|
|
mtx_lock(&sw_dev_mtx);
|
|
sp->sw_flags |= SW_CLOSING;
|
|
swap_pager_avail -= blist_fill(sp->sw_blist, 0, nblks);
|
|
swap_total -= nblks;
|
|
mtx_unlock(&sw_dev_mtx);
|
|
|
|
/*
|
|
* Page in the contents of the device and close it.
|
|
*/
|
|
swap_pager_swapoff(sp);
|
|
|
|
sp->sw_close(curthread, sp);
|
|
mtx_lock(&sw_dev_mtx);
|
|
sp->sw_id = NULL;
|
|
TAILQ_REMOVE(&swtailq, sp, sw_list);
|
|
nswapdev--;
|
|
if (nswapdev == 0) {
|
|
swap_pager_full = 2;
|
|
swap_pager_almost_full = 1;
|
|
}
|
|
if (swdevhd == sp)
|
|
swdevhd = NULL;
|
|
mtx_unlock(&sw_dev_mtx);
|
|
blist_destroy(sp->sw_blist);
|
|
free(sp, M_VMPGDATA);
|
|
return (0);
|
|
}
|
|
|
|
void
|
|
swapoff_all(void)
|
|
{
|
|
struct swdevt *sp, *spt;
|
|
const char *devname;
|
|
int error;
|
|
|
|
sx_xlock(&swdev_syscall_lock);
|
|
|
|
mtx_lock(&sw_dev_mtx);
|
|
TAILQ_FOREACH_SAFE(sp, &swtailq, sw_list, spt) {
|
|
mtx_unlock(&sw_dev_mtx);
|
|
if (vn_isdisk(sp->sw_vp, NULL))
|
|
devname = devtoname(sp->sw_vp->v_rdev);
|
|
else
|
|
devname = "[file]";
|
|
error = swapoff_one(sp, thread0.td_ucred);
|
|
if (error != 0) {
|
|
printf("Cannot remove swap device %s (error=%d), "
|
|
"skipping.\n", devname, error);
|
|
} else if (bootverbose) {
|
|
printf("Swap device %s removed.\n", devname);
|
|
}
|
|
mtx_lock(&sw_dev_mtx);
|
|
}
|
|
mtx_unlock(&sw_dev_mtx);
|
|
|
|
sx_xunlock(&swdev_syscall_lock);
|
|
}
|
|
|
|
void
|
|
swap_pager_status(int *total, int *used)
|
|
{
|
|
struct swdevt *sp;
|
|
|
|
*total = 0;
|
|
*used = 0;
|
|
mtx_lock(&sw_dev_mtx);
|
|
TAILQ_FOREACH(sp, &swtailq, sw_list) {
|
|
*total += sp->sw_nblks;
|
|
*used += sp->sw_used;
|
|
}
|
|
mtx_unlock(&sw_dev_mtx);
|
|
}
|
|
|
|
int
|
|
swap_dev_info(int name, struct xswdev *xs, char *devname, size_t len)
|
|
{
|
|
struct swdevt *sp;
|
|
const char *tmp_devname;
|
|
int error, n;
|
|
|
|
n = 0;
|
|
error = ENOENT;
|
|
mtx_lock(&sw_dev_mtx);
|
|
TAILQ_FOREACH(sp, &swtailq, sw_list) {
|
|
if (n != name) {
|
|
n++;
|
|
continue;
|
|
}
|
|
xs->xsw_version = XSWDEV_VERSION;
|
|
xs->xsw_dev = sp->sw_dev;
|
|
xs->xsw_flags = sp->sw_flags;
|
|
xs->xsw_nblks = sp->sw_nblks;
|
|
xs->xsw_used = sp->sw_used;
|
|
if (devname != NULL) {
|
|
if (vn_isdisk(sp->sw_vp, NULL))
|
|
tmp_devname = devtoname(sp->sw_vp->v_rdev);
|
|
else
|
|
tmp_devname = "[file]";
|
|
strncpy(devname, tmp_devname, len);
|
|
}
|
|
error = 0;
|
|
break;
|
|
}
|
|
mtx_unlock(&sw_dev_mtx);
|
|
return (error);
|
|
}
|
|
|
|
#if defined(COMPAT_FREEBSD11)
|
|
#define XSWDEV_VERSION_11 1
|
|
struct xswdev11 {
|
|
u_int xsw_version;
|
|
uint32_t xsw_dev;
|
|
int xsw_flags;
|
|
int xsw_nblks;
|
|
int xsw_used;
|
|
};
|
|
#endif
|
|
|
|
#if defined(__amd64__) && defined(COMPAT_FREEBSD32)
|
|
struct xswdev32 {
|
|
u_int xsw_version;
|
|
u_int xsw_dev1, xsw_dev2;
|
|
int xsw_flags;
|
|
int xsw_nblks;
|
|
int xsw_used;
|
|
};
|
|
#endif
|
|
|
|
static int
|
|
sysctl_vm_swap_info(SYSCTL_HANDLER_ARGS)
|
|
{
|
|
struct xswdev xs;
|
|
#if defined(__amd64__) && defined(COMPAT_FREEBSD32)
|
|
struct xswdev32 xs32;
|
|
#endif
|
|
#if defined(COMPAT_FREEBSD11)
|
|
struct xswdev11 xs11;
|
|
#endif
|
|
int error;
|
|
|
|
if (arg2 != 1) /* name length */
|
|
return (EINVAL);
|
|
error = swap_dev_info(*(int *)arg1, &xs, NULL, 0);
|
|
if (error != 0)
|
|
return (error);
|
|
#if defined(__amd64__) && defined(COMPAT_FREEBSD32)
|
|
if (req->oldlen == sizeof(xs32)) {
|
|
xs32.xsw_version = XSWDEV_VERSION;
|
|
xs32.xsw_dev1 = xs.xsw_dev;
|
|
xs32.xsw_dev2 = xs.xsw_dev >> 32;
|
|
xs32.xsw_flags = xs.xsw_flags;
|
|
xs32.xsw_nblks = xs.xsw_nblks;
|
|
xs32.xsw_used = xs.xsw_used;
|
|
error = SYSCTL_OUT(req, &xs32, sizeof(xs32));
|
|
return (error);
|
|
}
|
|
#endif
|
|
#if defined(COMPAT_FREEBSD11)
|
|
if (req->oldlen == sizeof(xs11)) {
|
|
xs11.xsw_version = XSWDEV_VERSION_11;
|
|
xs11.xsw_dev = xs.xsw_dev; /* truncation */
|
|
xs11.xsw_flags = xs.xsw_flags;
|
|
xs11.xsw_nblks = xs.xsw_nblks;
|
|
xs11.xsw_used = xs.xsw_used;
|
|
error = SYSCTL_OUT(req, &xs11, sizeof(xs11));
|
|
return (error);
|
|
}
|
|
#endif
|
|
error = SYSCTL_OUT(req, &xs, sizeof(xs));
|
|
return (error);
|
|
}
|
|
|
|
SYSCTL_INT(_vm, OID_AUTO, nswapdev, CTLFLAG_RD, &nswapdev, 0,
|
|
"Number of swap devices");
|
|
SYSCTL_NODE(_vm, OID_AUTO, swap_info, CTLFLAG_RD | CTLFLAG_MPSAFE,
|
|
sysctl_vm_swap_info,
|
|
"Swap statistics by device");
|
|
|
|
/*
|
|
* Count the approximate swap usage in pages for a vmspace. The
|
|
* shadowed or not yet copied on write swap blocks are not accounted.
|
|
* The map must be locked.
|
|
*/
|
|
long
|
|
vmspace_swap_count(struct vmspace *vmspace)
|
|
{
|
|
vm_map_t map;
|
|
vm_map_entry_t cur;
|
|
vm_object_t object;
|
|
struct swblk *sb;
|
|
vm_pindex_t e, pi;
|
|
long count;
|
|
int i;
|
|
|
|
map = &vmspace->vm_map;
|
|
count = 0;
|
|
|
|
VM_MAP_ENTRY_FOREACH(cur, map) {
|
|
if ((cur->eflags & MAP_ENTRY_IS_SUB_MAP) != 0)
|
|
continue;
|
|
object = cur->object.vm_object;
|
|
if (object == NULL || object->type != OBJT_SWAP)
|
|
continue;
|
|
VM_OBJECT_RLOCK(object);
|
|
if (object->type != OBJT_SWAP)
|
|
goto unlock;
|
|
pi = OFF_TO_IDX(cur->offset);
|
|
e = pi + OFF_TO_IDX(cur->end - cur->start);
|
|
for (;; pi = sb->p + SWAP_META_PAGES) {
|
|
sb = SWAP_PCTRIE_LOOKUP_GE(
|
|
&object->un_pager.swp.swp_blks, pi);
|
|
if (sb == NULL || sb->p >= e)
|
|
break;
|
|
for (i = 0; i < SWAP_META_PAGES; i++) {
|
|
if (sb->p + i < e &&
|
|
sb->d[i] != SWAPBLK_NONE)
|
|
count++;
|
|
}
|
|
}
|
|
unlock:
|
|
VM_OBJECT_RUNLOCK(object);
|
|
}
|
|
return (count);
|
|
}
|
|
|
|
/*
|
|
* GEOM backend
|
|
*
|
|
* Swapping onto disk devices.
|
|
*
|
|
*/
|
|
|
|
static g_orphan_t swapgeom_orphan;
|
|
|
|
static struct g_class g_swap_class = {
|
|
.name = "SWAP",
|
|
.version = G_VERSION,
|
|
.orphan = swapgeom_orphan,
|
|
};
|
|
|
|
DECLARE_GEOM_CLASS(g_swap_class, g_class);
|
|
|
|
|
|
static void
|
|
swapgeom_close_ev(void *arg, int flags)
|
|
{
|
|
struct g_consumer *cp;
|
|
|
|
cp = arg;
|
|
g_access(cp, -1, -1, 0);
|
|
g_detach(cp);
|
|
g_destroy_consumer(cp);
|
|
}
|
|
|
|
/*
|
|
* Add a reference to the g_consumer for an inflight transaction.
|
|
*/
|
|
static void
|
|
swapgeom_acquire(struct g_consumer *cp)
|
|
{
|
|
|
|
mtx_assert(&sw_dev_mtx, MA_OWNED);
|
|
cp->index++;
|
|
}
|
|
|
|
/*
|
|
* Remove a reference from the g_consumer. Post a close event if all
|
|
* references go away, since the function might be called from the
|
|
* biodone context.
|
|
*/
|
|
static void
|
|
swapgeom_release(struct g_consumer *cp, struct swdevt *sp)
|
|
{
|
|
|
|
mtx_assert(&sw_dev_mtx, MA_OWNED);
|
|
cp->index--;
|
|
if (cp->index == 0) {
|
|
if (g_post_event(swapgeom_close_ev, cp, M_NOWAIT, NULL) == 0)
|
|
sp->sw_id = NULL;
|
|
}
|
|
}
|
|
|
|
static void
|
|
swapgeom_done(struct bio *bp2)
|
|
{
|
|
struct swdevt *sp;
|
|
struct buf *bp;
|
|
struct g_consumer *cp;
|
|
|
|
bp = bp2->bio_caller2;
|
|
cp = bp2->bio_from;
|
|
bp->b_ioflags = bp2->bio_flags;
|
|
if (bp2->bio_error)
|
|
bp->b_ioflags |= BIO_ERROR;
|
|
bp->b_resid = bp->b_bcount - bp2->bio_completed;
|
|
bp->b_error = bp2->bio_error;
|
|
bp->b_caller1 = NULL;
|
|
bufdone(bp);
|
|
sp = bp2->bio_caller1;
|
|
mtx_lock(&sw_dev_mtx);
|
|
swapgeom_release(cp, sp);
|
|
mtx_unlock(&sw_dev_mtx);
|
|
g_destroy_bio(bp2);
|
|
}
|
|
|
|
static void
|
|
swapgeom_strategy(struct buf *bp, struct swdevt *sp)
|
|
{
|
|
struct bio *bio;
|
|
struct g_consumer *cp;
|
|
|
|
mtx_lock(&sw_dev_mtx);
|
|
cp = sp->sw_id;
|
|
if (cp == NULL) {
|
|
mtx_unlock(&sw_dev_mtx);
|
|
bp->b_error = ENXIO;
|
|
bp->b_ioflags |= BIO_ERROR;
|
|
bufdone(bp);
|
|
return;
|
|
}
|
|
swapgeom_acquire(cp);
|
|
mtx_unlock(&sw_dev_mtx);
|
|
if (bp->b_iocmd == BIO_WRITE)
|
|
bio = g_new_bio();
|
|
else
|
|
bio = g_alloc_bio();
|
|
if (bio == NULL) {
|
|
mtx_lock(&sw_dev_mtx);
|
|
swapgeom_release(cp, sp);
|
|
mtx_unlock(&sw_dev_mtx);
|
|
bp->b_error = ENOMEM;
|
|
bp->b_ioflags |= BIO_ERROR;
|
|
printf("swap_pager: cannot allocate bio\n");
|
|
bufdone(bp);
|
|
return;
|
|
}
|
|
|
|
bp->b_caller1 = bio;
|
|
bio->bio_caller1 = sp;
|
|
bio->bio_caller2 = bp;
|
|
bio->bio_cmd = bp->b_iocmd;
|
|
bio->bio_offset = (bp->b_blkno - sp->sw_first) * PAGE_SIZE;
|
|
bio->bio_length = bp->b_bcount;
|
|
bio->bio_done = swapgeom_done;
|
|
if (!buf_mapped(bp)) {
|
|
bio->bio_ma = bp->b_pages;
|
|
bio->bio_data = unmapped_buf;
|
|
bio->bio_ma_offset = (vm_offset_t)bp->b_offset & PAGE_MASK;
|
|
bio->bio_ma_n = bp->b_npages;
|
|
bio->bio_flags |= BIO_UNMAPPED;
|
|
} else {
|
|
bio->bio_data = bp->b_data;
|
|
bio->bio_ma = NULL;
|
|
}
|
|
g_io_request(bio, cp);
|
|
return;
|
|
}
|
|
|
|
static void
|
|
swapgeom_orphan(struct g_consumer *cp)
|
|
{
|
|
struct swdevt *sp;
|
|
int destroy;
|
|
|
|
mtx_lock(&sw_dev_mtx);
|
|
TAILQ_FOREACH(sp, &swtailq, sw_list) {
|
|
if (sp->sw_id == cp) {
|
|
sp->sw_flags |= SW_CLOSING;
|
|
break;
|
|
}
|
|
}
|
|
/*
|
|
* Drop reference we were created with. Do directly since we're in a
|
|
* special context where we don't have to queue the call to
|
|
* swapgeom_close_ev().
|
|
*/
|
|
cp->index--;
|
|
destroy = ((sp != NULL) && (cp->index == 0));
|
|
if (destroy)
|
|
sp->sw_id = NULL;
|
|
mtx_unlock(&sw_dev_mtx);
|
|
if (destroy)
|
|
swapgeom_close_ev(cp, 0);
|
|
}
|
|
|
|
static void
|
|
swapgeom_close(struct thread *td, struct swdevt *sw)
|
|
{
|
|
struct g_consumer *cp;
|
|
|
|
mtx_lock(&sw_dev_mtx);
|
|
cp = sw->sw_id;
|
|
sw->sw_id = NULL;
|
|
mtx_unlock(&sw_dev_mtx);
|
|
|
|
/*
|
|
* swapgeom_close() may be called from the biodone context,
|
|
* where we cannot perform topology changes. Delegate the
|
|
* work to the events thread.
|
|
*/
|
|
if (cp != NULL)
|
|
g_waitfor_event(swapgeom_close_ev, cp, M_WAITOK, NULL);
|
|
}
|
|
|
|
static int
|
|
swapongeom_locked(struct cdev *dev, struct vnode *vp)
|
|
{
|
|
struct g_provider *pp;
|
|
struct g_consumer *cp;
|
|
static struct g_geom *gp;
|
|
struct swdevt *sp;
|
|
u_long nblks;
|
|
int error;
|
|
|
|
pp = g_dev_getprovider(dev);
|
|
if (pp == NULL)
|
|
return (ENODEV);
|
|
mtx_lock(&sw_dev_mtx);
|
|
TAILQ_FOREACH(sp, &swtailq, sw_list) {
|
|
cp = sp->sw_id;
|
|
if (cp != NULL && cp->provider == pp) {
|
|
mtx_unlock(&sw_dev_mtx);
|
|
return (EBUSY);
|
|
}
|
|
}
|
|
mtx_unlock(&sw_dev_mtx);
|
|
if (gp == NULL)
|
|
gp = g_new_geomf(&g_swap_class, "swap");
|
|
cp = g_new_consumer(gp);
|
|
cp->index = 1; /* Number of active I/Os, plus one for being active. */
|
|
cp->flags |= G_CF_DIRECT_SEND | G_CF_DIRECT_RECEIVE;
|
|
g_attach(cp, pp);
|
|
/*
|
|
* XXX: Every time you think you can improve the margin for
|
|
* footshooting, somebody depends on the ability to do so:
|
|
* savecore(8) wants to write to our swapdev so we cannot
|
|
* set an exclusive count :-(
|
|
*/
|
|
error = g_access(cp, 1, 1, 0);
|
|
if (error != 0) {
|
|
g_detach(cp);
|
|
g_destroy_consumer(cp);
|
|
return (error);
|
|
}
|
|
nblks = pp->mediasize / DEV_BSIZE;
|
|
swaponsomething(vp, cp, nblks, swapgeom_strategy,
|
|
swapgeom_close, dev2udev(dev),
|
|
(pp->flags & G_PF_ACCEPT_UNMAPPED) != 0 ? SW_UNMAPPED : 0);
|
|
return (0);
|
|
}
|
|
|
|
static int
|
|
swapongeom(struct vnode *vp)
|
|
{
|
|
int error;
|
|
|
|
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
|
|
if (vp->v_type != VCHR || (vp->v_iflag & VI_DOOMED) != 0) {
|
|
error = ENOENT;
|
|
} else {
|
|
g_topology_lock();
|
|
error = swapongeom_locked(vp->v_rdev, vp);
|
|
g_topology_unlock();
|
|
}
|
|
VOP_UNLOCK(vp, 0);
|
|
return (error);
|
|
}
|
|
|
|
/*
|
|
* VNODE backend
|
|
*
|
|
* This is used mainly for network filesystem (read: probably only tested
|
|
* with NFS) swapfiles.
|
|
*
|
|
*/
|
|
|
|
static void
|
|
swapdev_strategy(struct buf *bp, struct swdevt *sp)
|
|
{
|
|
struct vnode *vp2;
|
|
|
|
bp->b_blkno = ctodb(bp->b_blkno - sp->sw_first);
|
|
|
|
vp2 = sp->sw_id;
|
|
vhold(vp2);
|
|
if (bp->b_iocmd == BIO_WRITE) {
|
|
if (bp->b_bufobj)
|
|
bufobj_wdrop(bp->b_bufobj);
|
|
bufobj_wref(&vp2->v_bufobj);
|
|
}
|
|
if (bp->b_bufobj != &vp2->v_bufobj)
|
|
bp->b_bufobj = &vp2->v_bufobj;
|
|
bp->b_vp = vp2;
|
|
bp->b_iooffset = dbtob(bp->b_blkno);
|
|
bstrategy(bp);
|
|
return;
|
|
}
|
|
|
|
static void
|
|
swapdev_close(struct thread *td, struct swdevt *sp)
|
|
{
|
|
|
|
VOP_CLOSE(sp->sw_vp, FREAD | FWRITE, td->td_ucred, td);
|
|
vrele(sp->sw_vp);
|
|
}
|
|
|
|
|
|
static int
|
|
swaponvp(struct thread *td, struct vnode *vp, u_long nblks)
|
|
{
|
|
struct swdevt *sp;
|
|
int error;
|
|
|
|
if (nblks == 0)
|
|
return (ENXIO);
|
|
mtx_lock(&sw_dev_mtx);
|
|
TAILQ_FOREACH(sp, &swtailq, sw_list) {
|
|
if (sp->sw_id == vp) {
|
|
mtx_unlock(&sw_dev_mtx);
|
|
return (EBUSY);
|
|
}
|
|
}
|
|
mtx_unlock(&sw_dev_mtx);
|
|
|
|
(void) vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
|
|
#ifdef MAC
|
|
error = mac_system_check_swapon(td->td_ucred, vp);
|
|
if (error == 0)
|
|
#endif
|
|
error = VOP_OPEN(vp, FREAD | FWRITE, td->td_ucred, td, NULL);
|
|
(void) VOP_UNLOCK(vp, 0);
|
|
if (error)
|
|
return (error);
|
|
|
|
swaponsomething(vp, vp, nblks, swapdev_strategy, swapdev_close,
|
|
NODEV, 0);
|
|
return (0);
|
|
}
|
|
|
|
static int
|
|
sysctl_swap_async_max(SYSCTL_HANDLER_ARGS)
|
|
{
|
|
int error, new, n;
|
|
|
|
new = nsw_wcount_async_max;
|
|
error = sysctl_handle_int(oidp, &new, 0, req);
|
|
if (error != 0 || req->newptr == NULL)
|
|
return (error);
|
|
|
|
if (new > nswbuf / 2 || new < 1)
|
|
return (EINVAL);
|
|
|
|
mtx_lock(&swbuf_mtx);
|
|
while (nsw_wcount_async_max != new) {
|
|
/*
|
|
* Adjust difference. If the current async count is too low,
|
|
* we will need to sqeeze our update slowly in. Sleep with a
|
|
* higher priority than getpbuf() to finish faster.
|
|
*/
|
|
n = new - nsw_wcount_async_max;
|
|
if (nsw_wcount_async + n >= 0) {
|
|
nsw_wcount_async += n;
|
|
nsw_wcount_async_max += n;
|
|
wakeup(&nsw_wcount_async);
|
|
} else {
|
|
nsw_wcount_async_max -= nsw_wcount_async;
|
|
nsw_wcount_async = 0;
|
|
msleep(&nsw_wcount_async, &swbuf_mtx, PSWP,
|
|
"swpsysctl", 0);
|
|
}
|
|
}
|
|
mtx_unlock(&swbuf_mtx);
|
|
|
|
return (0);
|
|
}
|
|
|
|
static void
|
|
swap_pager_update_writecount(vm_object_t object, vm_offset_t start,
|
|
vm_offset_t end)
|
|
{
|
|
|
|
VM_OBJECT_WLOCK(object);
|
|
KASSERT((object->flags & OBJ_NOSPLIT) != 0,
|
|
("Splittable object with writecount"));
|
|
object->un_pager.swp.writemappings += (vm_ooffset_t)end - start;
|
|
VM_OBJECT_WUNLOCK(object);
|
|
}
|
|
|
|
static void
|
|
swap_pager_release_writecount(vm_object_t object, vm_offset_t start,
|
|
vm_offset_t end)
|
|
{
|
|
|
|
VM_OBJECT_WLOCK(object);
|
|
KASSERT((object->flags & OBJ_NOSPLIT) != 0,
|
|
("Splittable object with writecount"));
|
|
object->un_pager.swp.writemappings -= (vm_ooffset_t)end - start;
|
|
VM_OBJECT_WUNLOCK(object);
|
|
}
|