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2582 lines
66 KiB
C
2582 lines
66 KiB
C
/*-
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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_mac.h"
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#include "opt_swap.h"
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#include "opt_vm.h"
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/conf.h>
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#include <sys/kernel.h>
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#include <sys/proc.h>
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#include <sys/bio.h>
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#include <sys/buf.h>
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#include <sys/disk.h>
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#include <sys/fcntl.h>
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#include <sys/mount.h>
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#include <sys/namei.h>
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#include <sys/vnode.h>
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#include <sys/mac.h>
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#include <sys/malloc.h>
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#include <sys/sysctl.h>
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#include <sys/sysproto.h>
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#include <sys/blist.h>
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#include <sys/lock.h>
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#include <sys/sx.h>
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#include <sys/vmmeter.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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* SWB_NPAGES must be a power of 2. It may be set to 1, 2, 4, 8, or 16
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* pages per allocation. We recommend you stick with the default of 8.
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* The 16-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 16
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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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/*
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* Piecemeal swap metadata structure. Swap is stored in a radix tree.
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*
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* If SWB_NPAGES is 8 and sizeof(char *) == sizeof(daddr_t), our radix
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* is basically 8. Assuming PAGE_SIZE == 4096, one tree level represents
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* 32K worth of data, two levels represent 256K, three levels represent
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* 2 MBytes. This is acceptable.
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*
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* Overall memory utilization is about the same as the old swap structure.
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*/
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#define SWCORRECT(n) (sizeof(void *) * (n) / sizeof(daddr_t))
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#define SWAP_META_PAGES (SWB_NPAGES * 2)
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#define SWAP_META_MASK (SWAP_META_PAGES - 1)
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typedef int32_t swblk_t; /*
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* swap offset. This is the type used to
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* address the "virtual swap device" and
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* therefore the maximum swap space is
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* 2^32 pages.
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*/
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struct swdevt;
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typedef void sw_strategy_t(struct buf *bp, struct swdevt *sw);
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typedef void sw_close_t(struct thread *td, struct swdevt *sw);
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/*
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* Swap device table
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*/
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struct swdevt {
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int sw_flags;
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int sw_nblks;
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int sw_used;
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dev_t sw_dev;
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struct vnode *sw_vp;
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void *sw_id;
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swblk_t sw_first;
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swblk_t sw_end;
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struct blist *sw_blist;
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TAILQ_ENTRY(swdevt) sw_list;
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sw_strategy_t *sw_strategy;
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sw_close_t *sw_close;
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};
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#define SW_CLOSING 0x04
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struct swblock {
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struct swblock *swb_hnext;
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vm_object_t swb_object;
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vm_pindex_t swb_index;
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int swb_count;
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daddr_t swb_pages[SWAP_META_PAGES];
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};
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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 int swdev_syscall_active = 0; /* serialize swap(on|off) */
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static void swapdev_strategy(struct buf *, struct swdevt *sw);
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#define SWM_FREE 0x02 /* free, period */
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#define SWM_POP 0x04 /* pop out */
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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 int nsw_rcount; /* free read buffers */
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static int nsw_wcount_sync; /* limit write buffers / synchronous */
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static int nsw_wcount_async; /* limit write buffers / asynchronous */
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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 struct swblock **swhash;
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static int swhash_mask;
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static struct mtx swhash_mtx;
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static int swap_async_max = 4; /* maximum in-progress async I/O's */
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static struct sx sw_alloc_sx;
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SYSCTL_INT(_vm, OID_AUTO, swap_async_max,
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CTLFLAG_RW, &swap_async_max, 0, "Maximum running async swap ops");
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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 mtx sw_alloc_mtx; /* protect list manipulation */
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static struct pagerlst swap_pager_object_list[NOBJLISTS];
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static uma_zone_t swap_zone;
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static struct vm_object swap_zone_obj;
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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);
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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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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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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_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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};
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/*
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* dmmax is in page-sized chunks with the new swap system. It was
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* dev-bsized chunks in the old. dmmax is always a power of 2.
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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 dmmax;
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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,
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CTLFLAG_RD, &dmmax, 0, "Maximum size of a swap block");
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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 int swapongeom(struct thread *, 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 thread *td);
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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, int npages);
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static daddr_t swp_pager_getswapspace(int npages);
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/*
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* Metadata functions
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*/
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static struct swblock **swp_pager_hash(vm_object_t object, vm_pindex_t index);
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static void 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, daddr_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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/*
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* SWP_SIZECHECK() - update swap_pager_full indication
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*
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* update the swap_pager_almost_full indication and warn when we are
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* about to run out of swap space, using lowat/hiwat hysteresis.
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*
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* Clear swap_pager_full ( task killing ) indication when lowat is met.
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*
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* No restrictions on call
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* This routine may not block.
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* This routine must be called at splvm()
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*/
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static void
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swp_sizecheck(void)
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{
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if (swap_pager_avail < nswap_lowat) {
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if (swap_pager_almost_full == 0) {
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printf("swap_pager: out of swap space\n");
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swap_pager_almost_full = 1;
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}
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} else {
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swap_pager_full = 0;
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if (swap_pager_avail > nswap_hiwat)
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swap_pager_almost_full = 0;
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}
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}
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/*
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* SWP_PAGER_HASH() - hash swap meta data
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*
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* This is an helper function which hashes the swapblk given
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* the object and page index. It returns a pointer to a pointer
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* to the object, or a pointer to a NULL pointer if it could not
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* find a swapblk.
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*
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* This routine must be called at splvm().
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*/
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static struct swblock **
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swp_pager_hash(vm_object_t object, vm_pindex_t index)
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{
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struct swblock **pswap;
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struct swblock *swap;
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index &= ~(vm_pindex_t)SWAP_META_MASK;
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pswap = &swhash[(index ^ (int)(intptr_t)object) & swhash_mask];
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while ((swap = *pswap) != NULL) {
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if (swap->swb_object == object &&
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swap->swb_index == index
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) {
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break;
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}
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pswap = &swap->swb_hnext;
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}
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return (pswap);
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}
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/*
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* SWAP_PAGER_INIT() - initialize the swap pager!
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*
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* Expected to be started from system init. NOTE: This code is run
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* before much else so be careful what you depend on. Most of the VM
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* system has yet to be initialized at this point.
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*/
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static void
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swap_pager_init(void)
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{
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/*
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* Initialize object lists
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*/
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int i;
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for (i = 0; i < NOBJLISTS; ++i)
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TAILQ_INIT(&swap_pager_object_list[i]);
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mtx_init(&sw_alloc_mtx, "swap_pager list", NULL, MTX_DEF);
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mtx_init(&sw_dev_mtx, "swapdev", NULL, MTX_DEF);
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/*
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* Device Stripe, in PAGE_SIZE'd blocks
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*/
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dmmax = SWB_NPAGES * 2;
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}
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/*
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* SWAP_PAGER_SWAP_INIT() - swap pager initialization from pageout process
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*
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* Expected to be started from pageout process once, prior to entering
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* its main loop.
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*/
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void
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swap_pager_swap_init(void)
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{
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int n, n2;
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/*
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* Number of in-transit swap bp operations. Don't
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* exhaust the pbufs completely. Make sure we
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* initialize workable values (0 will work for hysteresis
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* but it isn't very efficient).
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*
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* The nsw_cluster_max is constrained by the bp->b_pages[]
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* array (MAXPHYS/PAGE_SIZE) and our locally defined
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* MAX_PAGEOUT_CLUSTER. Also be aware that swap ops are
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* constrained by the swap device interleave stripe size.
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*
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* Currently we hardwire nsw_wcount_async to 4. This limit is
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* designed to prevent other I/O from having high latencies due to
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* our pageout I/O. The value 4 works well for one or two active swap
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* devices but is probably a little low if you have more. Even so,
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* a higher value would probably generate only a limited improvement
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* with three or four active swap devices since the system does not
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* typically have to pageout at extreme bandwidths. We will want
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* at least 2 per swap devices, and 4 is a pretty good value if you
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* have one NFS swap device due to the command/ack latency over NFS.
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* So it all works out pretty well.
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*/
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nsw_cluster_max = min((MAXPHYS/PAGE_SIZE), MAX_PAGEOUT_CLUSTER);
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mtx_lock(&pbuf_mtx);
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nsw_rcount = (nswbuf + 1) / 2;
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nsw_wcount_sync = (nswbuf + 3) / 4;
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nsw_wcount_async = 4;
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nsw_wcount_async_max = nsw_wcount_async;
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mtx_unlock(&pbuf_mtx);
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/*
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* Initialize our zone. Right now I'm just guessing on the number
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* we need based on the number of pages in the system. Each swblock
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* can hold 16 pages, so this is probably overkill. This reservation
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* is typically limited to around 32MB by default.
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*/
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n = cnt.v_page_count / 2;
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if (maxswzone && n > maxswzone / sizeof(struct swblock))
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n = maxswzone / sizeof(struct swblock);
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n2 = n;
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swap_zone = uma_zcreate("SWAPMETA", sizeof(struct swblock), NULL, NULL,
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NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE | UMA_ZONE_VM);
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if (swap_zone == NULL)
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panic("failed to create swap_zone.");
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do {
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if (uma_zone_set_obj(swap_zone, &swap_zone_obj, n))
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break;
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/*
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* if the allocation failed, try a zone two thirds the
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* size of the previous attempt.
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*/
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n -= ((n + 2) / 3);
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} while (n > 0);
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if (n2 != n)
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printf("Swap zone entries reduced from %d to %d.\n", n2, n);
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n2 = n;
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/*
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* Initialize our meta-data hash table. The swapper does not need to
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* be quite as efficient as the VM system, so we do not use an
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* oversized hash table.
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*
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* n: size of hash table, must be power of 2
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* swhash_mask: hash table index mask
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*/
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for (n = 1; n < n2 / 8; n *= 2)
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;
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swhash = malloc(sizeof(struct swblock *) * n, M_VMPGDATA, M_WAITOK | M_ZERO);
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swhash_mask = n - 1;
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mtx_init(&swhash_mtx, "swap_pager swhash", NULL, MTX_DEF);
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}
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/*
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* SWAP_PAGER_ALLOC() - allocate a new OBJT_SWAP VM object and instantiate
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* its metadata structures.
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*
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* This routine is called from the mmap and fork code to create a new
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* OBJT_SWAP object. We do this by creating an OBJT_DEFAULT object
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* and then converting it with swp_pager_meta_build().
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*
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|
* This routine may block in vm_object_allocate() and create a named
|
|
* object lookup race, so we must interlock. We must also run at
|
|
* splvm() for the object lookup to handle races with interrupts, but
|
|
* we do not have to maintain splvm() in between the lookup and the
|
|
* add because (I believe) it is not possible to attempt to create
|
|
* a new swap object w/handle when a default object with that handle
|
|
* already exists.
|
|
*
|
|
* MPSAFE
|
|
*/
|
|
static vm_object_t
|
|
swap_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot,
|
|
vm_ooffset_t offset)
|
|
{
|
|
vm_object_t object;
|
|
vm_pindex_t pindex;
|
|
|
|
pindex = OFF_TO_IDX(offset + PAGE_MASK + size);
|
|
|
|
if (handle) {
|
|
mtx_lock(&Giant);
|
|
/*
|
|
* 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) {
|
|
vm_object_reference(object);
|
|
} else {
|
|
object = vm_object_allocate(OBJT_DEFAULT, pindex);
|
|
object->handle = handle;
|
|
|
|
VM_OBJECT_LOCK(object);
|
|
swp_pager_meta_build(object, 0, SWAPBLK_NONE);
|
|
VM_OBJECT_UNLOCK(object);
|
|
}
|
|
sx_xunlock(&sw_alloc_sx);
|
|
mtx_unlock(&Giant);
|
|
} else {
|
|
object = vm_object_allocate(OBJT_DEFAULT, pindex);
|
|
|
|
VM_OBJECT_LOCK(object);
|
|
swp_pager_meta_build(object, 0, SWAPBLK_NONE);
|
|
VM_OBJECT_UNLOCK(object);
|
|
}
|
|
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.
|
|
*
|
|
* This routine may block, but no longer does.
|
|
*
|
|
* The object must be locked or unreferenceable.
|
|
*/
|
|
static void
|
|
swap_pager_dealloc(vm_object_t object)
|
|
{
|
|
|
|
/*
|
|
* Remove from list right away so lookups will fail if we block for
|
|
* pageout completion.
|
|
*/
|
|
if (object->handle != NULL) {
|
|
mtx_lock(&sw_alloc_mtx);
|
|
TAILQ_REMOVE(NOBJLIST(object->handle), object, pager_object_list);
|
|
mtx_unlock(&sw_alloc_mtx);
|
|
}
|
|
|
|
VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
|
|
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);
|
|
}
|
|
|
|
/************************************************************************
|
|
* SWAP PAGER BITMAP ROUTINES *
|
|
************************************************************************/
|
|
|
|
/*
|
|
* SWP_PAGER_GETSWAPSPACE() - allocate raw swap space
|
|
*
|
|
* Allocate swap for the requested 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.
|
|
*
|
|
* Must be called at splvm() to avoid races with bitmap frees from
|
|
* vm_page_remove() aka swap_pager_page_removed().
|
|
*
|
|
* This routine may not block
|
|
* This routine must be called at splvm().
|
|
*
|
|
* We allocate in round-robin fashion from the configured devices.
|
|
*/
|
|
static daddr_t
|
|
swp_pager_getswapspace(int npages)
|
|
{
|
|
daddr_t blk;
|
|
struct swdevt *sp;
|
|
int i;
|
|
|
|
blk = SWAPBLK_NONE;
|
|
mtx_lock(&sw_dev_mtx);
|
|
sp = swdevhd;
|
|
for (i = 0; i < nswapdev; i++) {
|
|
if (sp == NULL)
|
|
sp = TAILQ_FIRST(&swtailq);
|
|
if (!(sp->sw_flags & SW_CLOSING)) {
|
|
blk = blist_alloc(sp->sw_blist, npages);
|
|
if (blk != SWAPBLK_NONE) {
|
|
blk += sp->sw_first;
|
|
sp->sw_used += npages;
|
|
swap_pager_avail -= npages;
|
|
swp_sizecheck();
|
|
swdevhd = TAILQ_NEXT(sp, sw_list);
|
|
goto done;
|
|
}
|
|
}
|
|
sp = TAILQ_NEXT(sp, sw_list);
|
|
}
|
|
if (swap_pager_full != 2) {
|
|
printf("swap_pager_getswapspace(%d): failed\n", npages);
|
|
swap_pager_full = 2;
|
|
swap_pager_almost_full = 1;
|
|
}
|
|
swdevhd = NULL;
|
|
done:
|
|
mtx_unlock(&sw_dev_mtx);
|
|
return (blk);
|
|
}
|
|
|
|
static int
|
|
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 (bp->b_blkno >= sp->sw_first && bp->b_blkno < sp->sw_end) {
|
|
mtx_unlock(&sw_dev_mtx);
|
|
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.
|
|
*
|
|
* Note: This routine may not block (it could in the old swap code),
|
|
* and through the use of the new blist routines it does not block.
|
|
*
|
|
* We must be called at splvm() to avoid races with bitmap frees from
|
|
* vm_page_remove() aka swap_pager_page_removed().
|
|
*
|
|
* This routine may not block
|
|
* This routine must be called at splvm().
|
|
*/
|
|
static void
|
|
swp_pager_freeswapspace(daddr_t blk, int npages)
|
|
{
|
|
struct swdevt *sp;
|
|
|
|
mtx_lock(&sw_dev_mtx);
|
|
TAILQ_FOREACH(sp, &swtailq, sw_list) {
|
|
if (blk >= sp->sw_first && blk < sp->sw_end) {
|
|
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");
|
|
}
|
|
|
|
/*
|
|
* 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.
|
|
*
|
|
* This routine may be called at any spl. We up our spl to splvm temporarily
|
|
* in order to perform the metadata removal.
|
|
*/
|
|
void
|
|
swap_pager_freespace(vm_object_t object, vm_pindex_t start, vm_size_t size)
|
|
{
|
|
|
|
VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
|
|
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 zerod. 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)
|
|
{
|
|
int n = 0;
|
|
daddr_t blk = SWAPBLK_NONE;
|
|
vm_pindex_t beg = start; /* save start index */
|
|
|
|
VM_OBJECT_LOCK(object);
|
|
while (size) {
|
|
if (n == 0) {
|
|
n = BLIST_MAX_ALLOC;
|
|
while ((blk = swp_pager_getswapspace(n)) == SWAPBLK_NONE) {
|
|
n >>= 1;
|
|
if (n == 0) {
|
|
swp_pager_meta_free(object, beg, start - beg);
|
|
VM_OBJECT_UNLOCK(object);
|
|
return (-1);
|
|
}
|
|
}
|
|
}
|
|
swp_pager_meta_build(object, start, blk);
|
|
--size;
|
|
++start;
|
|
++blk;
|
|
--n;
|
|
}
|
|
swp_pager_meta_free(object, start, n);
|
|
VM_OBJECT_UNLOCK(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 block. It may block allocating metadata
|
|
* indirectly through swp_pager_meta_build() or if paging is still in
|
|
* progress on the source.
|
|
*
|
|
* This routine can be called at any spl
|
|
*
|
|
* XXX vm_page_collapse() kinda expects us not to block because we
|
|
* supposedly do not need to allocate memory, but for the moment we
|
|
* *may* have to get a little memory from the zone allocator, but
|
|
* it is taken from the interrupt memory. We should be ok.
|
|
*
|
|
* 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 or
|
|
* inaccessible (XXX are they ?)
|
|
*/
|
|
void
|
|
swap_pager_copy(vm_object_t srcobject, vm_object_t dstobject,
|
|
vm_pindex_t offset, int destroysource)
|
|
{
|
|
vm_pindex_t i;
|
|
|
|
VM_OBJECT_LOCK_ASSERT(srcobject, MA_OWNED);
|
|
VM_OBJECT_LOCK_ASSERT(dstobject, MA_OWNED);
|
|
|
|
/*
|
|
* If destroysource is set, we remove the source object from the
|
|
* swap_pager internal queue now.
|
|
*/
|
|
if (destroysource) {
|
|
if (srcobject->handle != NULL) {
|
|
mtx_lock(&sw_alloc_mtx);
|
|
TAILQ_REMOVE(
|
|
NOBJLIST(srcobject->handle),
|
|
srcobject,
|
|
pager_object_list
|
|
);
|
|
mtx_unlock(&sw_alloc_mtx);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* transfer source to destination.
|
|
*/
|
|
for (i = 0; i < dstobject->size; ++i) {
|
|
daddr_t dstaddr;
|
|
|
|
/*
|
|
* Locate (without changing) the swapblk on the destination,
|
|
* unless it is invalid in which case free it silently, or
|
|
* if the destination is a resident page, in which case the
|
|
* source is thrown away.
|
|
*/
|
|
dstaddr = swp_pager_meta_ctl(dstobject, i, 0);
|
|
|
|
if (dstaddr == SWAPBLK_NONE) {
|
|
/*
|
|
* Destination has no swapblk and is not resident,
|
|
* copy source.
|
|
*/
|
|
daddr_t srcaddr;
|
|
|
|
srcaddr = swp_pager_meta_ctl(
|
|
srcobject,
|
|
i + offset,
|
|
SWM_POP
|
|
);
|
|
|
|
if (srcaddr != SWAPBLK_NONE) {
|
|
/*
|
|
* swp_pager_meta_build() can sleep.
|
|
*/
|
|
vm_object_pip_add(srcobject, 1);
|
|
VM_OBJECT_UNLOCK(srcobject);
|
|
vm_object_pip_add(dstobject, 1);
|
|
swp_pager_meta_build(dstobject, i, srcaddr);
|
|
vm_object_pip_wakeup(dstobject);
|
|
VM_OBJECT_LOCK(srcobject);
|
|
vm_object_pip_wakeup(srcobject);
|
|
}
|
|
} else {
|
|
/*
|
|
* Destination has valid swapblk or it is represented
|
|
* by a resident page. We destroy the sourceblock.
|
|
*/
|
|
|
|
swp_pager_meta_ctl(srcobject, i + offset, SWM_FREE);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Free left over swap blocks in source.
|
|
*
|
|
* We have to revert the type to OBJT_DEFAULT so we do not accidently
|
|
* 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 within a reasonable
|
|
* distance. We do not try to restrict it to the swap device stripe
|
|
* (that is handled in getpages/putpages). It probably isn't worth
|
|
* doing here.
|
|
*/
|
|
static boolean_t
|
|
swap_pager_haspage(vm_object_t object, vm_pindex_t pindex, int *before, int *after)
|
|
{
|
|
daddr_t blk0;
|
|
|
|
VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
|
|
/*
|
|
* 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) {
|
|
int i;
|
|
|
|
for (i = 1; i < (SWB_NPAGES/2); ++i) {
|
|
daddr_t blk;
|
|
|
|
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) {
|
|
int i;
|
|
|
|
for (i = 1; i < (SWB_NPAGES/2); ++i) {
|
|
daddr_t blk;
|
|
|
|
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 block
|
|
* This routine must be called at splvm()
|
|
*/
|
|
static void
|
|
swap_pager_unswapped(vm_page_t m)
|
|
{
|
|
|
|
VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED);
|
|
swp_pager_meta_ctl(m->object, m->pindex, SWM_FREE);
|
|
}
|
|
|
|
/*
|
|
* SWAP_PAGER_GETPAGES() - bring pages in from swap
|
|
*
|
|
* Attempt to retrieve (m, count) pages from backing store, but make
|
|
* sure we retrieve at least m[reqpage]. We try to load in as large
|
|
* a chunk surrounding m[reqpage] as is contiguous in swap and which
|
|
* belongs to the same object.
|
|
*
|
|
* The code is designed for asynchronous operation and
|
|
* immediate-notification of 'reqpage' but tends not to be
|
|
* used that way. Please do not optimize-out this algorithmic
|
|
* feature, I intend to improve on it in the future.
|
|
*
|
|
* The parent has a single vm_object_pip_add() reference prior to
|
|
* calling us and we should return with the same.
|
|
*
|
|
* The parent has BUSY'd the pages. We should return with 'm'
|
|
* left busy, but the others adjusted.
|
|
*/
|
|
static int
|
|
swap_pager_getpages(vm_object_t object, vm_page_t *m, int count, int reqpage)
|
|
{
|
|
struct buf *bp;
|
|
vm_page_t mreq;
|
|
int i;
|
|
int j;
|
|
daddr_t blk;
|
|
|
|
mreq = m[reqpage];
|
|
|
|
KASSERT(mreq->object == object,
|
|
("swap_pager_getpages: object mismatch %p/%p",
|
|
object, mreq->object));
|
|
|
|
/*
|
|
* Calculate range to retrieve. The pages have already been assigned
|
|
* their swapblks. We require a *contiguous* range but we know it to
|
|
* not span devices. If we do not supply it, bad things
|
|
* happen. Note that blk, iblk & jblk can be SWAPBLK_NONE, but the
|
|
* loops are set up such that the case(s) are handled implicitly.
|
|
*
|
|
* The swp_*() calls must be made at splvm(). vm_page_free() does
|
|
* not need to be, but it will go a little faster if it is.
|
|
*/
|
|
blk = swp_pager_meta_ctl(mreq->object, mreq->pindex, 0);
|
|
|
|
for (i = reqpage - 1; i >= 0; --i) {
|
|
daddr_t iblk;
|
|
|
|
iblk = swp_pager_meta_ctl(m[i]->object, m[i]->pindex, 0);
|
|
if (blk != iblk + (reqpage - i))
|
|
break;
|
|
}
|
|
++i;
|
|
|
|
for (j = reqpage + 1; j < count; ++j) {
|
|
daddr_t jblk;
|
|
|
|
jblk = swp_pager_meta_ctl(m[j]->object, m[j]->pindex, 0);
|
|
if (blk != jblk - (j - reqpage))
|
|
break;
|
|
}
|
|
|
|
/*
|
|
* free pages outside our collection range. Note: we never free
|
|
* mreq, it must remain busy throughout.
|
|
*/
|
|
if (0 < i || j < count) {
|
|
int k;
|
|
|
|
vm_page_lock_queues();
|
|
for (k = 0; k < i; ++k)
|
|
vm_page_free(m[k]);
|
|
for (k = j; k < count; ++k)
|
|
vm_page_free(m[k]);
|
|
vm_page_unlock_queues();
|
|
}
|
|
|
|
/*
|
|
* Return VM_PAGER_FAIL if we have nothing to do. Return mreq
|
|
* still busy, but the others unbusied.
|
|
*/
|
|
if (blk == SWAPBLK_NONE)
|
|
return (VM_PAGER_FAIL);
|
|
|
|
/*
|
|
* Getpbuf() can sleep.
|
|
*/
|
|
VM_OBJECT_UNLOCK(object);
|
|
/*
|
|
* Get a swap buffer header to perform the IO
|
|
*/
|
|
bp = getpbuf(&nsw_rcount);
|
|
bp->b_flags |= B_PAGING;
|
|
|
|
/*
|
|
* map our page(s) into kva for input
|
|
*/
|
|
pmap_qenter((vm_offset_t)bp->b_data, m + i, j - i);
|
|
|
|
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 - (reqpage - i);
|
|
bp->b_bcount = PAGE_SIZE * (j - i);
|
|
bp->b_bufsize = PAGE_SIZE * (j - i);
|
|
bp->b_pager.pg_reqpage = reqpage - i;
|
|
|
|
VM_OBJECT_LOCK(object);
|
|
vm_page_lock_queues();
|
|
{
|
|
int k;
|
|
|
|
for (k = i; k < j; ++k) {
|
|
bp->b_pages[k - i] = m[k];
|
|
vm_page_flag_set(m[k], PG_SWAPINPROG);
|
|
}
|
|
}
|
|
vm_page_unlock_queues();
|
|
bp->b_npages = j - i;
|
|
|
|
cnt.v_swapin++;
|
|
cnt.v_swappgsin += bp->b_npages;
|
|
|
|
/*
|
|
* We still hold the lock on mreq, and our automatic completion routine
|
|
* does not remove it.
|
|
*/
|
|
vm_object_pip_add(object, bp->b_npages);
|
|
VM_OBJECT_UNLOCK(object);
|
|
|
|
/*
|
|
* 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 m[] 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 page we want to complete. PG_SWAPINPROG is always
|
|
* cleared on completion. If an I/O error occurs, SWAPBLK_NONE
|
|
* is set in the meta-data.
|
|
*/
|
|
vm_page_lock_queues();
|
|
while ((mreq->flags & PG_SWAPINPROG) != 0) {
|
|
vm_page_flag_set(mreq, PG_WANTED | PG_REFERENCED);
|
|
cnt.v_intrans++;
|
|
if (msleep(mreq, &vm_page_queue_mtx, 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);
|
|
}
|
|
}
|
|
vm_page_unlock_queues();
|
|
|
|
VM_OBJECT_LOCK(object);
|
|
/*
|
|
* mreq is left busied after completion, but all the other pages
|
|
* are freed. If we had an unrecoverable read error the page will
|
|
* not be valid.
|
|
*/
|
|
if (mreq->valid != VM_PAGE_BITS_ALL) {
|
|
return (VM_PAGER_ERROR);
|
|
} else {
|
|
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_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 whos rtvals[] entry is not set to VM_PAGER_PEND on return.
|
|
* We need to unbusy the rest on I/O completion.
|
|
*/
|
|
void
|
|
swap_pager_putpages(vm_object_t object, vm_page_t *m, int count,
|
|
boolean_t sync, int *rtvals)
|
|
{
|
|
int i;
|
|
int n = 0;
|
|
|
|
GIANT_REQUIRED;
|
|
if (count && m[0]->object != object) {
|
|
panic("swap_pager_getpages: object mismatch %p/%p",
|
|
object,
|
|
m[0]->object
|
|
);
|
|
}
|
|
|
|
/*
|
|
* Step 1
|
|
*
|
|
* Turn object into OBJT_SWAP
|
|
* check for bogus sysops
|
|
* force sync if not pageout process
|
|
*/
|
|
if (object->type != OBJT_SWAP)
|
|
swp_pager_meta_build(object, 0, SWAPBLK_NONE);
|
|
VM_OBJECT_UNLOCK(object);
|
|
|
|
if (curproc != pageproc)
|
|
sync = TRUE;
|
|
|
|
/*
|
|
* Step 2
|
|
*
|
|
* Update nsw parameters from swap_async_max sysctl values.
|
|
* Do not let the sysop crash the machine with bogus numbers.
|
|
*/
|
|
mtx_lock(&pbuf_mtx);
|
|
if (swap_async_max != nsw_wcount_async_max) {
|
|
int n;
|
|
|
|
/*
|
|
* limit range
|
|
*/
|
|
if ((n = swap_async_max) > nswbuf / 2)
|
|
n = nswbuf / 2;
|
|
if (n < 1)
|
|
n = 1;
|
|
swap_async_max = n;
|
|
|
|
/*
|
|
* Adjust difference ( if possible ). If the current async
|
|
* count is too low, we may not be able to make the adjustment
|
|
* at this time.
|
|
*/
|
|
n -= nsw_wcount_async_max;
|
|
if (nsw_wcount_async + n >= 0) {
|
|
nsw_wcount_async += n;
|
|
nsw_wcount_async_max += n;
|
|
wakeup(&nsw_wcount_async);
|
|
}
|
|
}
|
|
mtx_unlock(&pbuf_mtx);
|
|
|
|
/*
|
|
* Step 3
|
|
*
|
|
* 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) {
|
|
int j;
|
|
struct buf *bp;
|
|
daddr_t blk;
|
|
|
|
/*
|
|
* Maximum I/O size is limited by a number of factors.
|
|
*/
|
|
n = min(BLIST_MAX_ALLOC, count - i);
|
|
n = min(n, nsw_cluster_max);
|
|
|
|
/*
|
|
* Get biggest block of swap we can. If we fail, fall
|
|
* back and try to allocate a smaller block. Don't go
|
|
* overboard trying to allocate space if it would overly
|
|
* fragment swap.
|
|
*/
|
|
while (
|
|
(blk = swp_pager_getswapspace(n)) == SWAPBLK_NONE &&
|
|
n > 4
|
|
) {
|
|
n >>= 1;
|
|
}
|
|
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 (sync == TRUE) {
|
|
bp = getpbuf(&nsw_wcount_sync);
|
|
} else {
|
|
bp = getpbuf(&nsw_wcount_async);
|
|
bp->b_flags = B_ASYNC;
|
|
}
|
|
bp->b_flags |= B_PAGING;
|
|
bp->b_iocmd = BIO_WRITE;
|
|
|
|
pmap_qenter((vm_offset_t)bp->b_data, &m[i], n);
|
|
|
|
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_LOCK(object);
|
|
for (j = 0; j < n; ++j) {
|
|
vm_page_t mreq = m[i+j];
|
|
|
|
swp_pager_meta_build(
|
|
mreq->object,
|
|
mreq->pindex,
|
|
blk + j
|
|
);
|
|
vm_page_dirty(mreq);
|
|
rtvals[i+j] = VM_PAGER_OK;
|
|
|
|
vm_page_lock_queues();
|
|
vm_page_flag_set(mreq, PG_SWAPINPROG);
|
|
vm_page_unlock_queues();
|
|
bp->b_pages[j] = mreq;
|
|
}
|
|
VM_OBJECT_UNLOCK(object);
|
|
bp->b_npages = n;
|
|
/*
|
|
* Must set dirty range for NFS to work.
|
|
*/
|
|
bp->b_dirtyoff = 0;
|
|
bp->b_dirtyend = bp->b_bcount;
|
|
|
|
cnt.v_swapout++;
|
|
cnt.v_swappgsout += bp->b_npages;
|
|
|
|
/*
|
|
* asynchronous
|
|
*
|
|
* NOTE: b_blkno is destroyed by the call to swapdev_strategy
|
|
*/
|
|
if (sync == FALSE) {
|
|
bp->b_iodone = swp_pager_async_iodone;
|
|
BUF_KERNPROC(bp);
|
|
swp_pager_strategy(bp);
|
|
|
|
for (j = 0; j < n; ++j)
|
|
rtvals[i+j] = VM_PAGER_PEND;
|
|
/* restart outter loop */
|
|
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, then update rtvals.
|
|
* We just set the rtvals[] to VM_PAGER_PEND so we can call
|
|
* our async completion routine at the end, thus avoiding a
|
|
* double-free.
|
|
*/
|
|
bwait(bp, PVM, "swwrt");
|
|
for (j = 0; j < n; ++j)
|
|
rtvals[i+j] = VM_PAGER_PEND;
|
|
/*
|
|
* Now that we are through with the bp, we can call the
|
|
* normal async completion, which frees everything up.
|
|
*/
|
|
swp_pager_async_iodone(bp);
|
|
}
|
|
VM_OBJECT_LOCK(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.
|
|
*
|
|
* For READ operations, the pages are PG_BUSY'd. For WRITE operations,
|
|
* the pages are vm_page_t->busy'd. For READ operations, we PG_BUSY
|
|
* unbusy all pages except the 'main' request page. For WRITE
|
|
* operations, we vm_page_t->busy'd unbusy all pages ( we can do this
|
|
* because we marked them all VM_PAGER_PEND on return from putpages ).
|
|
*
|
|
* This routine may not block.
|
|
* This routine is called at splbio() or better
|
|
*
|
|
* We up ourselves to splvm() as required for various vm_page related
|
|
* calls.
|
|
*/
|
|
static void
|
|
swp_pager_async_iodone(struct buf *bp)
|
|
{
|
|
int i;
|
|
vm_object_t object = NULL;
|
|
|
|
/*
|
|
* report error
|
|
*/
|
|
if (bp->b_ioflags & BIO_ERROR) {
|
|
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
|
|
*/
|
|
pmap_qremove((vm_offset_t)bp->b_data, bp->b_npages);
|
|
|
|
if (bp->b_npages) {
|
|
object = bp->b_pages[0]->object;
|
|
VM_OBJECT_LOCK(object);
|
|
}
|
|
vm_page_lock_queues();
|
|
/*
|
|
* 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];
|
|
|
|
vm_page_flag_clear(m, PG_SWAPINPROG);
|
|
|
|
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) {
|
|
/*
|
|
* When reading, reqpage needs to stay
|
|
* locked for the parent, but all other
|
|
* pages can be freed. We still want to
|
|
* wakeup the parent waiting on the page,
|
|
* though. ( also: pg_reqpage can be -1 and
|
|
* not match anything ).
|
|
*
|
|
* We have to wake specifically requested pages
|
|
* up too because we cleared PG_SWAPINPROG and
|
|
* someone may be waiting for that.
|
|
*
|
|
* NOTE: for reads, m->dirty will probably
|
|
* be overridden by the original caller of
|
|
* getpages so don't play cute tricks here.
|
|
*
|
|
* XXX IT IS NOT LEGAL TO FREE THE PAGE HERE
|
|
* AS THIS MESSES WITH object->memq, and it is
|
|
* not legal to mess with object->memq from an
|
|
* interrupt.
|
|
*/
|
|
m->valid = 0;
|
|
if (i != bp->b_pager.pg_reqpage)
|
|
vm_page_free(m);
|
|
else
|
|
vm_page_flash(m);
|
|
/*
|
|
* If i == bp->b_pager.pg_reqpage, do not wake
|
|
* the page up. The caller needs to.
|
|
*/
|
|
} else {
|
|
/*
|
|
* If a write error occurs, reactivate page
|
|
* so it doesn't clog the inactive list,
|
|
* then finish the I/O.
|
|
*/
|
|
vm_page_dirty(m);
|
|
vm_page_activate(m);
|
|
vm_page_io_finish(m);
|
|
}
|
|
} else if (bp->b_iocmd == BIO_READ) {
|
|
/*
|
|
* For read success, clear dirty bits. Nobody should
|
|
* have this page mapped but don't take any chances,
|
|
* make sure the pmap modify bits are also cleared.
|
|
*
|
|
* 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.
|
|
*
|
|
* If not the requested page then deactivate it.
|
|
*
|
|
* Note that the requested page, reqpage, is left
|
|
* busied, but we still have to wake it up. The
|
|
* other pages are released (unbusied) by
|
|
* vm_page_wakeup(). We do not set reqpage's
|
|
* valid bits here, it is up to the caller.
|
|
*/
|
|
pmap_clear_modify(m);
|
|
m->valid = VM_PAGE_BITS_ALL;
|
|
vm_page_undirty(m);
|
|
|
|
/*
|
|
* We have to wake specifically requested pages
|
|
* up too because we cleared PG_SWAPINPROG and
|
|
* could be waiting for it in getpages. However,
|
|
* be sure to not unbusy getpages specifically
|
|
* requested page - getpages expects it to be
|
|
* left busy.
|
|
*/
|
|
if (i != bp->b_pager.pg_reqpage) {
|
|
vm_page_deactivate(m);
|
|
vm_page_wakeup(m);
|
|
} else {
|
|
vm_page_flash(m);
|
|
}
|
|
} else {
|
|
/*
|
|
* For write success, clear the modify and dirty
|
|
* status, then finish the I/O ( which decrements the
|
|
* busy count and possibly wakes waiter's up ).
|
|
*/
|
|
pmap_clear_modify(m);
|
|
vm_page_undirty(m);
|
|
vm_page_io_finish(m);
|
|
if (vm_page_count_severe())
|
|
vm_page_try_to_cache(m);
|
|
}
|
|
}
|
|
vm_page_unlock_queues();
|
|
|
|
/*
|
|
* 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_UNLOCK(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
|
|
*/
|
|
relpbuf(
|
|
bp,
|
|
((bp->b_iocmd == BIO_READ) ? &nsw_rcount :
|
|
((bp->b_flags & B_ASYNC) ?
|
|
&nsw_wcount_async :
|
|
&nsw_wcount_sync
|
|
)
|
|
)
|
|
);
|
|
}
|
|
|
|
/*
|
|
* swap_pager_isswapped:
|
|
*
|
|
* Return 1 if at least one page in the given object is paged
|
|
* out to the given swap device.
|
|
*
|
|
* This routine may not block.
|
|
*/
|
|
int
|
|
swap_pager_isswapped(vm_object_t object, struct swdevt *sp)
|
|
{
|
|
daddr_t index = 0;
|
|
int bcount;
|
|
int i;
|
|
|
|
VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
|
|
if (object->type != OBJT_SWAP)
|
|
return (0);
|
|
|
|
mtx_lock(&swhash_mtx);
|
|
for (bcount = 0; bcount < object->un_pager.swp.swp_bcount; bcount++) {
|
|
struct swblock *swap;
|
|
|
|
if ((swap = *swp_pager_hash(object, index)) != NULL) {
|
|
for (i = 0; i < SWAP_META_PAGES; ++i) {
|
|
if (swp_pager_isondev(swap->swb_pages[i], sp)) {
|
|
mtx_unlock(&swhash_mtx);
|
|
return (1);
|
|
}
|
|
}
|
|
}
|
|
index += SWAP_META_PAGES;
|
|
if (index > 0x20000000)
|
|
panic("swap_pager_isswapped: failed to locate all swap meta blocks");
|
|
}
|
|
mtx_unlock(&swhash_mtx);
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* SWP_PAGER_FORCE_PAGEIN() - force a swap block to be paged in
|
|
*
|
|
* This routine dissociates the page at the given index within a
|
|
* swap block from its backing store, paging it in if necessary.
|
|
* If the page is paged in, it is placed in the inactive queue,
|
|
* since it had its backing store ripped out from under it.
|
|
* We also attempt to swap in all other pages in the swap block,
|
|
* we only guarantee that the one at the specified index is
|
|
* paged in.
|
|
*
|
|
* XXX - The code to page the whole block in doesn't work, so we
|
|
* revert to the one-by-one behavior for now. Sigh.
|
|
*/
|
|
static inline void
|
|
swp_pager_force_pagein(vm_object_t object, vm_pindex_t pindex)
|
|
{
|
|
vm_page_t m;
|
|
|
|
vm_object_pip_add(object, 1);
|
|
m = vm_page_grab(object, pindex, VM_ALLOC_NORMAL|VM_ALLOC_RETRY);
|
|
if (m->valid == VM_PAGE_BITS_ALL) {
|
|
vm_object_pip_subtract(object, 1);
|
|
vm_page_lock_queues();
|
|
vm_page_activate(m);
|
|
vm_page_dirty(m);
|
|
vm_page_wakeup(m);
|
|
vm_page_unlock_queues();
|
|
vm_pager_page_unswapped(m);
|
|
return;
|
|
}
|
|
|
|
if (swap_pager_getpages(object, &m, 1, 0) != VM_PAGER_OK)
|
|
panic("swap_pager_force_pagein: read from swap failed");/*XXX*/
|
|
vm_object_pip_subtract(object, 1);
|
|
vm_page_lock_queues();
|
|
vm_page_dirty(m);
|
|
vm_page_dontneed(m);
|
|
vm_page_wakeup(m);
|
|
vm_page_unlock_queues();
|
|
vm_pager_page_unswapped(m);
|
|
}
|
|
|
|
/*
|
|
* 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)
|
|
{
|
|
struct swblock *swap;
|
|
int i, j, retries;
|
|
|
|
GIANT_REQUIRED;
|
|
|
|
retries = 0;
|
|
full_rescan:
|
|
mtx_lock(&swhash_mtx);
|
|
for (i = 0; i <= swhash_mask; i++) { /* '<=' is correct here */
|
|
restart:
|
|
for (swap = swhash[i]; swap != NULL; swap = swap->swb_hnext) {
|
|
vm_object_t object = swap->swb_object;
|
|
vm_pindex_t pindex = swap->swb_index;
|
|
for (j = 0; j < SWAP_META_PAGES; ++j) {
|
|
if (swp_pager_isondev(swap->swb_pages[j], sp)) {
|
|
/* avoid deadlock */
|
|
if (!VM_OBJECT_TRYLOCK(object)) {
|
|
break;
|
|
} else {
|
|
mtx_unlock(&swhash_mtx);
|
|
swp_pager_force_pagein(object,
|
|
pindex + j);
|
|
VM_OBJECT_UNLOCK(object);
|
|
mtx_lock(&swhash_mtx);
|
|
goto restart;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
mtx_unlock(&swhash_mtx);
|
|
if (sp->sw_used) {
|
|
int dummy;
|
|
/*
|
|
* 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);
|
|
}
|
|
tsleep(&dummy, PVM, "swpoff", hz / 20);
|
|
goto full_rescan;
|
|
}
|
|
}
|
|
|
|
/************************************************************************
|
|
* SWAP META DATA *
|
|
************************************************************************
|
|
*
|
|
* These routines manipulate the swap metadata stored in the
|
|
* OBJT_SWAP object. All swp_*() routines must be called at
|
|
* splvm() because swap can be freed up by the low level vm_page
|
|
* code which might be called from interrupts beyond what splbio() covers.
|
|
*
|
|
* 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_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 freed.
|
|
*
|
|
* This routine must be called at splvm(), except when used to convert
|
|
* an OBJT_DEFAULT object into an OBJT_SWAP object.
|
|
*/
|
|
static void
|
|
swp_pager_meta_build(vm_object_t object, vm_pindex_t pindex, daddr_t swapblk)
|
|
{
|
|
struct swblock *swap;
|
|
struct swblock **pswap;
|
|
int idx;
|
|
|
|
VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
|
|
/*
|
|
* Convert default object to swap object if necessary
|
|
*/
|
|
if (object->type != OBJT_SWAP) {
|
|
object->type = OBJT_SWAP;
|
|
object->un_pager.swp.swp_bcount = 0;
|
|
|
|
if (object->handle != NULL) {
|
|
mtx_lock(&sw_alloc_mtx);
|
|
TAILQ_INSERT_TAIL(
|
|
NOBJLIST(object->handle),
|
|
object,
|
|
pager_object_list
|
|
);
|
|
mtx_unlock(&sw_alloc_mtx);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Locate hash entry. If not found create, but if we aren't adding
|
|
* anything just return. If we run out of space in the map we wait
|
|
* and, since the hash table may have changed, retry.
|
|
*/
|
|
retry:
|
|
mtx_lock(&swhash_mtx);
|
|
pswap = swp_pager_hash(object, pindex);
|
|
|
|
if ((swap = *pswap) == NULL) {
|
|
int i;
|
|
|
|
if (swapblk == SWAPBLK_NONE)
|
|
goto done;
|
|
|
|
swap = *pswap = uma_zalloc(swap_zone, M_NOWAIT);
|
|
if (swap == NULL) {
|
|
mtx_unlock(&swhash_mtx);
|
|
VM_OBJECT_UNLOCK(object);
|
|
VM_WAIT;
|
|
VM_OBJECT_LOCK(object);
|
|
goto retry;
|
|
}
|
|
|
|
swap->swb_hnext = NULL;
|
|
swap->swb_object = object;
|
|
swap->swb_index = pindex & ~(vm_pindex_t)SWAP_META_MASK;
|
|
swap->swb_count = 0;
|
|
|
|
++object->un_pager.swp.swp_bcount;
|
|
|
|
for (i = 0; i < SWAP_META_PAGES; ++i)
|
|
swap->swb_pages[i] = SWAPBLK_NONE;
|
|
}
|
|
|
|
/*
|
|
* Delete prior contents of metadata
|
|
*/
|
|
idx = pindex & SWAP_META_MASK;
|
|
|
|
if (swap->swb_pages[idx] != SWAPBLK_NONE) {
|
|
swp_pager_freeswapspace(swap->swb_pages[idx], 1);
|
|
--swap->swb_count;
|
|
}
|
|
|
|
/*
|
|
* Enter block into metadata
|
|
*/
|
|
swap->swb_pages[idx] = swapblk;
|
|
if (swapblk != SWAPBLK_NONE)
|
|
++swap->swb_count;
|
|
done:
|
|
mtx_unlock(&swhash_mtx);
|
|
}
|
|
|
|
/*
|
|
* 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.
|
|
*
|
|
* This routine must be called at splvm()
|
|
*/
|
|
static void
|
|
swp_pager_meta_free(vm_object_t object, vm_pindex_t index, daddr_t count)
|
|
{
|
|
|
|
VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
|
|
if (object->type != OBJT_SWAP)
|
|
return;
|
|
|
|
while (count > 0) {
|
|
struct swblock **pswap;
|
|
struct swblock *swap;
|
|
|
|
mtx_lock(&swhash_mtx);
|
|
pswap = swp_pager_hash(object, index);
|
|
|
|
if ((swap = *pswap) != NULL) {
|
|
daddr_t v = swap->swb_pages[index & SWAP_META_MASK];
|
|
|
|
if (v != SWAPBLK_NONE) {
|
|
swp_pager_freeswapspace(v, 1);
|
|
swap->swb_pages[index & SWAP_META_MASK] =
|
|
SWAPBLK_NONE;
|
|
if (--swap->swb_count == 0) {
|
|
*pswap = swap->swb_hnext;
|
|
uma_zfree(swap_zone, swap);
|
|
--object->un_pager.swp.swp_bcount;
|
|
}
|
|
}
|
|
--count;
|
|
++index;
|
|
} else {
|
|
int n = SWAP_META_PAGES - (index & SWAP_META_MASK);
|
|
count -= n;
|
|
index += n;
|
|
}
|
|
mtx_unlock(&swhash_mtx);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* SWP_PAGER_META_FREE_ALL() - destroy all swap metadata associated with object
|
|
*
|
|
* This routine locates and destroys all swap metadata associated with
|
|
* an object.
|
|
*
|
|
* This routine must be called at splvm()
|
|
*/
|
|
static void
|
|
swp_pager_meta_free_all(vm_object_t object)
|
|
{
|
|
daddr_t index = 0;
|
|
|
|
VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
|
|
if (object->type != OBJT_SWAP)
|
|
return;
|
|
|
|
while (object->un_pager.swp.swp_bcount) {
|
|
struct swblock **pswap;
|
|
struct swblock *swap;
|
|
|
|
mtx_lock(&swhash_mtx);
|
|
pswap = swp_pager_hash(object, index);
|
|
if ((swap = *pswap) != NULL) {
|
|
int i;
|
|
|
|
for (i = 0; i < SWAP_META_PAGES; ++i) {
|
|
daddr_t v = swap->swb_pages[i];
|
|
if (v != SWAPBLK_NONE) {
|
|
--swap->swb_count;
|
|
swp_pager_freeswapspace(v, 1);
|
|
}
|
|
}
|
|
if (swap->swb_count != 0)
|
|
panic("swap_pager_meta_free_all: swb_count != 0");
|
|
*pswap = swap->swb_hnext;
|
|
uma_zfree(swap_zone, swap);
|
|
--object->un_pager.swp.swp_bcount;
|
|
}
|
|
mtx_unlock(&swhash_mtx);
|
|
index += SWAP_META_PAGES;
|
|
if (index > 0x20000000)
|
|
panic("swp_pager_meta_free_all: failed to locate all swap meta blocks");
|
|
}
|
|
}
|
|
|
|
/*
|
|
* SWP_PAGER_METACTL() - misc control of swap and vm_page_t meta data.
|
|
*
|
|
* This routine is capable of looking up, popping, or freeing
|
|
* swapblk assignments in the swap meta data or in the vm_page_t.
|
|
* The routine typically returns the swapblk being looked-up, or popped,
|
|
* or SWAPBLK_NONE if the block was freed, or SWAPBLK_NONE if the block
|
|
* was invalid. This routine will automatically free any invalid
|
|
* meta-data swapblks.
|
|
*
|
|
* It is not possible to store invalid swapblks in the swap meta data
|
|
* (other then a literal 'SWAPBLK_NONE'), so we don't bother checking.
|
|
*
|
|
* 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.
|
|
*
|
|
* This routine must be called at splvm().
|
|
*
|
|
* SWM_FREE remove and free swap block from metadata
|
|
* SWM_POP remove from meta data but do not free.. pop it out
|
|
*/
|
|
static daddr_t
|
|
swp_pager_meta_ctl(vm_object_t object, vm_pindex_t pindex, int flags)
|
|
{
|
|
struct swblock **pswap;
|
|
struct swblock *swap;
|
|
daddr_t r1;
|
|
int idx;
|
|
|
|
VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
|
|
/*
|
|
* The meta data only exists of the object is OBJT_SWAP
|
|
* and even then might not be allocated yet.
|
|
*/
|
|
if (object->type != OBJT_SWAP)
|
|
return (SWAPBLK_NONE);
|
|
|
|
r1 = SWAPBLK_NONE;
|
|
mtx_lock(&swhash_mtx);
|
|
pswap = swp_pager_hash(object, pindex);
|
|
|
|
if ((swap = *pswap) != NULL) {
|
|
idx = pindex & SWAP_META_MASK;
|
|
r1 = swap->swb_pages[idx];
|
|
|
|
if (r1 != SWAPBLK_NONE) {
|
|
if (flags & SWM_FREE) {
|
|
swp_pager_freeswapspace(r1, 1);
|
|
r1 = SWAPBLK_NONE;
|
|
}
|
|
if (flags & (SWM_FREE|SWM_POP)) {
|
|
swap->swb_pages[idx] = SWAPBLK_NONE;
|
|
if (--swap->swb_count == 0) {
|
|
*pswap = swap->swb_hnext;
|
|
uma_zfree(swap_zone, swap);
|
|
--object->un_pager.swp.swp_bcount;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
mtx_unlock(&swhash_mtx);
|
|
return (r1);
|
|
}
|
|
|
|
/*
|
|
* 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
|
|
swapon(struct thread *td, struct swapon_args *uap)
|
|
{
|
|
struct vattr attr;
|
|
struct vnode *vp;
|
|
struct nameidata nd;
|
|
int error;
|
|
|
|
mtx_lock(&Giant);
|
|
error = suser(td);
|
|
if (error)
|
|
goto done2;
|
|
|
|
while (swdev_syscall_active)
|
|
tsleep(&swdev_syscall_active, PUSER - 1, "swpon", 0);
|
|
swdev_syscall_active = 1;
|
|
|
|
/*
|
|
* Swap metadata may not fit in the KVM if we have physical
|
|
* memory of >1GB.
|
|
*/
|
|
if (swap_zone == NULL) {
|
|
error = ENOMEM;
|
|
goto done;
|
|
}
|
|
|
|
NDINIT(&nd, LOOKUP, ISOPEN | FOLLOW, 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(td, 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, td)) == 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:
|
|
swdev_syscall_active = 0;
|
|
wakeup_one(&swdev_syscall_active);
|
|
done2:
|
|
mtx_unlock(&Giant);
|
|
return (error);
|
|
}
|
|
|
|
static void
|
|
swaponsomething(struct vnode *vp, void *id, u_long nblks, sw_strategy_t *strategy, sw_close_t *close, dev_t dev)
|
|
{
|
|
struct swdevt *sp, *tsp;
|
|
swblk_t dvbase;
|
|
u_long mblocks;
|
|
|
|
/*
|
|
* 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 size to maximum of %lu blocks per swap unit\n",
|
|
mblocks);
|
|
nblks = 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);
|
|
|
|
sp = malloc(sizeof *sp, M_VMPGDATA, M_WAITOK | M_ZERO);
|
|
sp->sw_vp = vp;
|
|
sp->sw_id = id;
|
|
sp->sw_dev = dev;
|
|
sp->sw_flags = 0;
|
|
sp->sw_nblks = nblks;
|
|
sp->sw_used = 0;
|
|
sp->sw_strategy = strategy;
|
|
sp->sw_close = close;
|
|
|
|
sp->sw_blist = blist_create(nblks);
|
|
/*
|
|
* Do not free the first two block in order to avoid overwriting
|
|
* any bsd label at the front of the partition
|
|
*/
|
|
blist_free(sp->sw_blist, 2, nblks - 2);
|
|
|
|
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;
|
|
swp_sizecheck();
|
|
mtx_unlock(&sw_dev_mtx);
|
|
}
|
|
|
|
/*
|
|
* 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
|
|
swapoff(struct thread *td, struct swapoff_args *uap)
|
|
{
|
|
struct vnode *vp;
|
|
struct nameidata nd;
|
|
struct swdevt *sp;
|
|
int error;
|
|
|
|
error = suser(td);
|
|
if (error)
|
|
return (error);
|
|
|
|
mtx_lock(&Giant);
|
|
while (swdev_syscall_active)
|
|
tsleep(&swdev_syscall_active, PUSER - 1, "swpoff", 0);
|
|
swdev_syscall_active = 1;
|
|
|
|
NDINIT(&nd, LOOKUP, FOLLOW, 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);
|
|
done:
|
|
swdev_syscall_active = 0;
|
|
wakeup_one(&swdev_syscall_active);
|
|
mtx_unlock(&Giant);
|
|
return (error);
|
|
}
|
|
|
|
static int
|
|
swapoff_one(struct swdevt *sp, struct thread *td)
|
|
{
|
|
u_long nblks, dvbase;
|
|
#ifdef MAC
|
|
int error;
|
|
#endif
|
|
|
|
mtx_assert(&Giant, MA_OWNED);
|
|
#ifdef MAC
|
|
(void) vn_lock(sp->sw_vp, LK_EXCLUSIVE | LK_RETRY, td);
|
|
error = mac_check_system_swapoff(td->td_ucred, sp->sw_vp);
|
|
(void) VOP_UNLOCK(sp->sw_vp, 0, td);
|
|
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 (cnt.v_free_count + cnt.v_cache_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;
|
|
for (dvbase = 0; dvbase < sp->sw_end; dvbase += dmmax) {
|
|
swap_pager_avail -= blist_fill(sp->sw_blist,
|
|
dvbase, dmmax);
|
|
}
|
|
mtx_unlock(&sw_dev_mtx);
|
|
|
|
/*
|
|
* Page in the contents of the device and close it.
|
|
*/
|
|
swap_pager_swapoff(sp);
|
|
|
|
sp->sw_close(td, sp);
|
|
sp->sw_id = NULL;
|
|
mtx_lock(&sw_dev_mtx);
|
|
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;
|
|
|
|
mtx_lock(&Giant);
|
|
while (swdev_syscall_active)
|
|
tsleep(&swdev_syscall_active, PUSER - 1, "swpoff", 0);
|
|
swdev_syscall_active = 1;
|
|
|
|
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 = sp->sw_vp->v_rdev->si_name;
|
|
else
|
|
devname = "[file]";
|
|
error = swapoff_one(sp, &thread0);
|
|
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);
|
|
|
|
swdev_syscall_active = 0;
|
|
wakeup_one(&swdev_syscall_active);
|
|
mtx_unlock(&Giant);
|
|
}
|
|
|
|
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);
|
|
}
|
|
|
|
static int
|
|
sysctl_vm_swap_info(SYSCTL_HANDLER_ARGS)
|
|
{
|
|
int *name = (int *)arg1;
|
|
int error, n;
|
|
struct xswdev xs;
|
|
struct swdevt *sp;
|
|
|
|
if (arg2 != 1) /* name length */
|
|
return (EINVAL);
|
|
|
|
n = 0;
|
|
mtx_lock(&sw_dev_mtx);
|
|
TAILQ_FOREACH(sp, &swtailq, sw_list) {
|
|
if (n == *name) {
|
|
mtx_unlock(&sw_dev_mtx);
|
|
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;
|
|
|
|
error = SYSCTL_OUT(req, &xs, sizeof(xs));
|
|
return (error);
|
|
}
|
|
n++;
|
|
}
|
|
mtx_unlock(&sw_dev_mtx);
|
|
return (ENOENT);
|
|
}
|
|
|
|
SYSCTL_INT(_vm, OID_AUTO, nswapdev, CTLFLAG_RD, &nswapdev, 0,
|
|
"Number of swap devices");
|
|
SYSCTL_NODE(_vm, OID_AUTO, swap_info, CTLFLAG_RD, sysctl_vm_swap_info,
|
|
"Swap statistics by device");
|
|
|
|
/*
|
|
* vmspace_swap_count() - count the approximate swap useage in pages for a
|
|
* vmspace.
|
|
*
|
|
* The map must be locked.
|
|
*
|
|
* Swap useage is determined by taking the proportional swap used by
|
|
* VM objects backing the VM map. To make up for fractional losses,
|
|
* if the VM object has any swap use at all the associated map entries
|
|
* count for at least 1 swap page.
|
|
*/
|
|
int
|
|
vmspace_swap_count(struct vmspace *vmspace)
|
|
{
|
|
vm_map_t map = &vmspace->vm_map;
|
|
vm_map_entry_t cur;
|
|
int count = 0;
|
|
|
|
for (cur = map->header.next; cur != &map->header; cur = cur->next) {
|
|
vm_object_t object;
|
|
|
|
if ((cur->eflags & MAP_ENTRY_IS_SUB_MAP) == 0 &&
|
|
(object = cur->object.vm_object) != NULL) {
|
|
VM_OBJECT_LOCK(object);
|
|
if (object->type == OBJT_SWAP &&
|
|
object->un_pager.swp.swp_bcount != 0) {
|
|
int n = (cur->end - cur->start) / PAGE_SIZE;
|
|
|
|
count += object->un_pager.swp.swp_bcount *
|
|
SWAP_META_PAGES * n / object->size + 1;
|
|
}
|
|
VM_OBJECT_UNLOCK(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_done(struct bio *bp2)
|
|
{
|
|
struct buf *bp;
|
|
|
|
bp = bp2->bio_caller2;
|
|
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;
|
|
bufdone(bp);
|
|
g_destroy_bio(bp2);
|
|
}
|
|
|
|
static void
|
|
swapgeom_strategy(struct buf *bp, struct swdevt *sp)
|
|
{
|
|
struct bio *bio;
|
|
struct g_consumer *cp;
|
|
|
|
cp = sp->sw_id;
|
|
if (cp == NULL) {
|
|
bp->b_error = ENXIO;
|
|
bp->b_ioflags |= BIO_ERROR;
|
|
bufdone(bp);
|
|
return;
|
|
}
|
|
bio = g_alloc_bio();
|
|
#if 0
|
|
/*
|
|
* XXX: We shouldn't really sleep here when we run out of buffers
|
|
* XXX: but the alternative is worse right now.
|
|
*/
|
|
if (bio == NULL) {
|
|
bp->b_error = ENOMEM;
|
|
bp->b_ioflags |= BIO_ERROR;
|
|
bufdone(bp);
|
|
return;
|
|
}
|
|
#endif
|
|
bio->bio_caller2 = bp;
|
|
bio->bio_cmd = bp->b_iocmd;
|
|
bio->bio_data = bp->b_data;
|
|
bio->bio_offset = (bp->b_blkno - sp->sw_first) * PAGE_SIZE;
|
|
bio->bio_length = bp->b_bcount;
|
|
bio->bio_done = swapgeom_done;
|
|
g_io_request(bio, cp);
|
|
return;
|
|
}
|
|
|
|
static void
|
|
swapgeom_orphan(struct g_consumer *cp)
|
|
{
|
|
struct swdevt *sp;
|
|
|
|
mtx_lock(&sw_dev_mtx);
|
|
TAILQ_FOREACH(sp, &swtailq, sw_list)
|
|
if (sp->sw_id == cp)
|
|
sp->sw_id = NULL;
|
|
mtx_unlock(&sw_dev_mtx);
|
|
}
|
|
|
|
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);
|
|
}
|
|
|
|
static void
|
|
swapgeom_close(struct thread *td, struct swdevt *sw)
|
|
{
|
|
|
|
/* XXX: direct call when Giant untangled */
|
|
g_waitfor_event(swapgeom_close_ev, sw->sw_id, M_WAITOK, NULL);
|
|
}
|
|
|
|
|
|
struct swh0h0 {
|
|
struct cdev *dev;
|
|
struct vnode *vp;
|
|
int error;
|
|
};
|
|
|
|
static void
|
|
swapongeom_ev(void *arg, int flags)
|
|
{
|
|
struct swh0h0 *swh;
|
|
struct g_provider *pp;
|
|
struct g_consumer *cp;
|
|
static struct g_geom *gp;
|
|
struct swdevt *sp;
|
|
u_long nblks;
|
|
int error;
|
|
|
|
swh = arg;
|
|
swh->error = 0;
|
|
pp = g_dev_getprovider(swh->dev);
|
|
if (pp == NULL) {
|
|
swh->error = ENODEV;
|
|
return;
|
|
}
|
|
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);
|
|
swh->error = EBUSY;
|
|
return;
|
|
}
|
|
}
|
|
mtx_unlock(&sw_dev_mtx);
|
|
if (gp == NULL)
|
|
gp = g_new_geomf(&g_swap_class, "swap", NULL);
|
|
cp = g_new_consumer(gp);
|
|
g_attach(cp, pp);
|
|
/*
|
|
* XXX: Everytime 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) {
|
|
g_detach(cp);
|
|
g_destroy_consumer(cp);
|
|
swh->error = error;
|
|
return;
|
|
}
|
|
nblks = pp->mediasize / DEV_BSIZE;
|
|
swaponsomething(swh->vp, cp, nblks, swapgeom_strategy,
|
|
swapgeom_close, dev2udev(swh->dev));
|
|
swh->error = 0;
|
|
return;
|
|
}
|
|
|
|
static int
|
|
swapongeom(struct thread *td, struct vnode *vp)
|
|
{
|
|
int error;
|
|
struct swh0h0 swh;
|
|
|
|
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td);
|
|
|
|
swh.dev = vp->v_rdev;
|
|
swh.vp = vp;
|
|
swh.error = 0;
|
|
/* XXX: direct call when Giant untangled */
|
|
error = g_waitfor_event(swapongeom_ev, &swh, M_WAITOK, NULL);
|
|
if (!error)
|
|
error = swh.error;
|
|
VOP_UNLOCK(vp, 0, td);
|
|
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, td);
|
|
#ifdef MAC
|
|
error = mac_check_system_swapon(td->td_ucred, vp);
|
|
if (error == 0)
|
|
#endif
|
|
error = VOP_OPEN(vp, FREAD | FWRITE, td->td_ucred, td, -1);
|
|
(void) VOP_UNLOCK(vp, 0, td);
|
|
if (error)
|
|
return (error);
|
|
|
|
swaponsomething(vp, vp, nblks, swapdev_strategy, swapdev_close,
|
|
NODEV);
|
|
return (0);
|
|
}
|