2 * Copyright (c) 1998 Matthew Dillon,
3 * Copyright (c) 1994 John S. Dyson
4 * Copyright (c) 1990 University of Utah.
5 * Copyright (c) 1982, 1986, 1989, 1993
6 * The Regents of the University of California. All rights reserved.
8 * This code is derived from software contributed to Berkeley by
9 * the Systems Programming Group of the University of Utah Computer
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions
15 * 1. Redistributions of source code must retain the above copyright
16 * notice, this list of conditions and the following disclaimer.
17 * 2. Redistributions in binary form must reproduce the above copyright
18 * notice, this list of conditions and the following disclaimer in the
19 * documentation and/or other materials provided with the distribution.
20 * 3. All advertising materials mentioning features or use of this software
21 * must display the following acknowledgement:
22 * This product includes software developed by the University of
23 * California, Berkeley and its contributors.
24 * 4. Neither the name of the University nor the names of its contributors
25 * may be used to endorse or promote products derived from this software
26 * without specific prior written permission.
28 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
29 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
30 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
31 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
32 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
33 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
34 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
35 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
36 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
37 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
43 * Radix Bitmap 'blists'.
45 * - The new swapper uses the new radix bitmap code. This should scale
46 * to arbitrarily small or arbitrarily large swap spaces and an almost
47 * arbitrary degree of fragmentation.
51 * - on the fly reallocation of swap during putpages. The new system
52 * does not try to keep previously allocated swap blocks for dirty
55 * - on the fly deallocation of swap
57 * - No more garbage collection required. Unnecessarily allocated swap
58 * blocks only exist for dirty vm_page_t's now and these are already
59 * cycled (in a high-load system) by the pager. We also do on-the-fly
60 * removal of invalidated swap blocks when a page is destroyed
63 * from: Utah $Hdr: swap_pager.c 1.4 91/04/30$
65 * @(#)swap_pager.c 8.9 (Berkeley) 3/21/94
66 * @(#)vm_swap.c 8.5 (Berkeley) 2/17/94
69 #include <sys/cdefs.h>
70 __FBSDID("$FreeBSD$");
75 #include <sys/param.h>
76 #include <sys/systm.h>
78 #include <sys/kernel.h>
84 #include <sys/fcntl.h>
85 #include <sys/mount.h>
86 #include <sys/namei.h>
87 #include <sys/vnode.h>
88 #include <sys/malloc.h>
89 #include <sys/racct.h>
90 #include <sys/resource.h>
91 #include <sys/resourcevar.h>
92 #include <sys/rwlock.h>
93 #include <sys/sysctl.h>
94 #include <sys/sysproto.h>
95 #include <sys/blist.h>
98 #include <sys/vmmeter.h>
100 #include <security/mac/mac_framework.h>
104 #include <vm/vm_map.h>
105 #include <vm/vm_kern.h>
106 #include <vm/vm_object.h>
107 #include <vm/vm_page.h>
108 #include <vm/vm_pager.h>
109 #include <vm/vm_pageout.h>
110 #include <vm/vm_param.h>
111 #include <vm/swap_pager.h>
112 #include <vm/vm_extern.h>
115 #include <geom/geom.h>
118 * MAX_PAGEOUT_CLUSTER must be a power of 2 between 1 and 64.
119 * The 64-page limit is due to the radix code (kern/subr_blist.c).
121 #ifndef MAX_PAGEOUT_CLUSTER
122 #define MAX_PAGEOUT_CLUSTER 16
125 #if !defined(SWB_NPAGES)
126 #define SWB_NPAGES MAX_PAGEOUT_CLUSTER
130 * The swblock structure maps an object and a small, fixed-size range
131 * of page indices to disk addresses within a swap area.
132 * The collection of these mappings is implemented as a hash table.
133 * Unused disk addresses within a swap area are allocated and managed
136 #define SWAP_META_PAGES (SWB_NPAGES * 2)
137 #define SWAP_META_MASK (SWAP_META_PAGES - 1)
140 struct swblock *swb_hnext;
141 vm_object_t swb_object;
142 vm_pindex_t swb_index;
144 daddr_t swb_pages[SWAP_META_PAGES];
147 static MALLOC_DEFINE(M_VMPGDATA, "vm_pgdata", "swap pager private data");
148 static struct mtx sw_dev_mtx;
149 static TAILQ_HEAD(, swdevt) swtailq = TAILQ_HEAD_INITIALIZER(swtailq);
150 static struct swdevt *swdevhd; /* Allocate from here next */
151 static int nswapdev; /* Number of swap devices */
152 int swap_pager_avail;
153 static int swdev_syscall_active = 0; /* serialize swap(on|off) */
155 static vm_ooffset_t swap_total;
156 SYSCTL_QUAD(_vm, OID_AUTO, swap_total, CTLFLAG_RD, &swap_total, 0,
157 "Total amount of available swap storage.");
158 static vm_ooffset_t swap_reserved;
159 SYSCTL_QUAD(_vm, OID_AUTO, swap_reserved, CTLFLAG_RD, &swap_reserved, 0,
160 "Amount of swap storage needed to back all allocated anonymous memory.");
161 static int overcommit = 0;
162 SYSCTL_INT(_vm, OID_AUTO, overcommit, CTLFLAG_RW, &overcommit, 0,
163 "Configure virtual memory overcommit behavior. See tuning(7) "
165 static unsigned long swzone;
166 SYSCTL_ULONG(_vm, OID_AUTO, swzone, CTLFLAG_RD, &swzone, 0,
167 "Actual size of swap metadata zone");
168 static unsigned long swap_maxpages;
169 SYSCTL_ULONG(_vm, OID_AUTO, swap_maxpages, CTLFLAG_RD, &swap_maxpages, 0,
170 "Maximum amount of swap supported");
172 /* bits from overcommit */
173 #define SWAP_RESERVE_FORCE_ON (1 << 0)
174 #define SWAP_RESERVE_RLIMIT_ON (1 << 1)
175 #define SWAP_RESERVE_ALLOW_NONWIRED (1 << 2)
178 swap_reserve(vm_ooffset_t incr)
181 return (swap_reserve_by_cred(incr, curthread->td_ucred));
185 swap_reserve_by_cred(vm_ooffset_t incr, struct ucred *cred)
190 static struct timeval lastfail;
193 uip = cred->cr_ruidinfo;
195 if (incr & PAGE_MASK)
196 panic("swap_reserve: & PAGE_MASK");
201 error = racct_add(curproc, RACCT_SWAP, incr);
202 PROC_UNLOCK(curproc);
209 mtx_lock(&sw_dev_mtx);
210 r = swap_reserved + incr;
211 if (overcommit & SWAP_RESERVE_ALLOW_NONWIRED) {
212 s = cnt.v_page_count - cnt.v_free_reserved - cnt.v_wire_count;
217 if ((overcommit & SWAP_RESERVE_FORCE_ON) == 0 || r <= s ||
218 (error = priv_check(curthread, PRIV_VM_SWAP_NOQUOTA)) == 0) {
222 mtx_unlock(&sw_dev_mtx);
226 UIDINFO_VMSIZE_LOCK(uip);
227 if ((overcommit & SWAP_RESERVE_RLIMIT_ON) != 0 &&
228 uip->ui_vmsize + incr > lim_cur(curproc, RLIMIT_SWAP) &&
229 priv_check(curthread, PRIV_VM_SWAP_NORLIMIT))
232 uip->ui_vmsize += incr;
233 UIDINFO_VMSIZE_UNLOCK(uip);
234 PROC_UNLOCK(curproc);
236 mtx_lock(&sw_dev_mtx);
237 swap_reserved -= incr;
238 mtx_unlock(&sw_dev_mtx);
241 if (!res && ppsratecheck(&lastfail, &curfail, 1)) {
242 printf("uid %d, pid %d: swap reservation for %jd bytes failed\n",
243 uip->ui_uid, curproc->p_pid, incr);
249 racct_sub(curproc, RACCT_SWAP, incr);
250 PROC_UNLOCK(curproc);
258 swap_reserve_force(vm_ooffset_t incr)
262 mtx_lock(&sw_dev_mtx);
263 swap_reserved += incr;
264 mtx_unlock(&sw_dev_mtx);
268 racct_add_force(curproc, RACCT_SWAP, incr);
269 PROC_UNLOCK(curproc);
272 uip = curthread->td_ucred->cr_ruidinfo;
274 UIDINFO_VMSIZE_LOCK(uip);
275 uip->ui_vmsize += incr;
276 UIDINFO_VMSIZE_UNLOCK(uip);
277 PROC_UNLOCK(curproc);
281 swap_release(vm_ooffset_t decr)
286 cred = curthread->td_ucred;
287 swap_release_by_cred(decr, cred);
288 PROC_UNLOCK(curproc);
292 swap_release_by_cred(vm_ooffset_t decr, struct ucred *cred)
296 uip = cred->cr_ruidinfo;
298 if (decr & PAGE_MASK)
299 panic("swap_release: & PAGE_MASK");
301 mtx_lock(&sw_dev_mtx);
302 if (swap_reserved < decr)
303 panic("swap_reserved < decr");
304 swap_reserved -= decr;
305 mtx_unlock(&sw_dev_mtx);
307 UIDINFO_VMSIZE_LOCK(uip);
308 if (uip->ui_vmsize < decr)
309 printf("negative vmsize for uid = %d\n", uip->ui_uid);
310 uip->ui_vmsize -= decr;
311 UIDINFO_VMSIZE_UNLOCK(uip);
313 racct_sub_cred(cred, RACCT_SWAP, decr);
316 static void swapdev_strategy(struct buf *, struct swdevt *sw);
318 #define SWM_FREE 0x02 /* free, period */
319 #define SWM_POP 0x04 /* pop out */
321 int swap_pager_full = 2; /* swap space exhaustion (task killing) */
322 static int swap_pager_almost_full = 1; /* swap space exhaustion (w/hysteresis)*/
323 static int nsw_rcount; /* free read buffers */
324 static int nsw_wcount_sync; /* limit write buffers / synchronous */
325 static int nsw_wcount_async; /* limit write buffers / asynchronous */
326 static int nsw_wcount_async_max;/* assigned maximum */
327 static int nsw_cluster_max; /* maximum VOP I/O allowed */
329 static struct swblock **swhash;
330 static int swhash_mask;
331 static struct mtx swhash_mtx;
333 static int swap_async_max = 4; /* maximum in-progress async I/O's */
334 static struct sx sw_alloc_sx;
337 SYSCTL_INT(_vm, OID_AUTO, swap_async_max,
338 CTLFLAG_RW, &swap_async_max, 0, "Maximum running async swap ops");
341 * "named" and "unnamed" anon region objects. Try to reduce the overhead
342 * of searching a named list by hashing it just a little.
347 #define NOBJLIST(handle) \
348 (&swap_pager_object_list[((int)(intptr_t)handle >> 4) & (NOBJLISTS-1)])
350 static struct mtx sw_alloc_mtx; /* protect list manipulation */
351 static struct pagerlst swap_pager_object_list[NOBJLISTS];
352 static uma_zone_t swap_zone;
355 * pagerops for OBJT_SWAP - "swap pager". Some ops are also global procedure
356 * calls hooked from other parts of the VM system and do not appear here.
357 * (see vm/swap_pager.h).
360 swap_pager_alloc(void *handle, vm_ooffset_t size,
361 vm_prot_t prot, vm_ooffset_t offset, struct ucred *);
362 static void swap_pager_dealloc(vm_object_t object);
363 static int swap_pager_getpages(vm_object_t, vm_page_t *, int, int);
364 static void swap_pager_putpages(vm_object_t, vm_page_t *, int, boolean_t, int *);
366 swap_pager_haspage(vm_object_t object, vm_pindex_t pindex, int *before, int *after);
367 static void swap_pager_init(void);
368 static void swap_pager_unswapped(vm_page_t);
369 static void swap_pager_swapoff(struct swdevt *sp);
371 struct pagerops swappagerops = {
372 .pgo_init = swap_pager_init, /* early system initialization of pager */
373 .pgo_alloc = swap_pager_alloc, /* allocate an OBJT_SWAP object */
374 .pgo_dealloc = swap_pager_dealloc, /* deallocate an OBJT_SWAP object */
375 .pgo_getpages = swap_pager_getpages, /* pagein */
376 .pgo_putpages = swap_pager_putpages, /* pageout */
377 .pgo_haspage = swap_pager_haspage, /* get backing store status for page */
378 .pgo_pageunswapped = swap_pager_unswapped, /* remove swap related to page */
382 * swap_*() routines are externally accessible. swp_*() routines are
385 static int nswap_lowat = 128; /* in pages, swap_pager_almost_full warn */
386 static int nswap_hiwat = 512; /* in pages, swap_pager_almost_full warn */
388 SYSCTL_INT(_vm, OID_AUTO, dmmax, CTLFLAG_RD, &nsw_cluster_max, 0,
389 "Maximum size of a swap block in pages");
391 static void swp_sizecheck(void);
392 static void swp_pager_async_iodone(struct buf *bp);
393 static int swapongeom(struct thread *, struct vnode *);
394 static int swaponvp(struct thread *, struct vnode *, u_long);
395 static int swapoff_one(struct swdevt *sp, struct ucred *cred);
398 * Swap bitmap functions
400 static void swp_pager_freeswapspace(daddr_t blk, int npages);
401 static daddr_t swp_pager_getswapspace(int npages);
406 static struct swblock **swp_pager_hash(vm_object_t object, vm_pindex_t index);
407 static void swp_pager_meta_build(vm_object_t, vm_pindex_t, daddr_t);
408 static void swp_pager_meta_free(vm_object_t, vm_pindex_t, daddr_t);
409 static void swp_pager_meta_free_all(vm_object_t);
410 static daddr_t swp_pager_meta_ctl(vm_object_t, vm_pindex_t, int);
413 swp_pager_free_nrpage(vm_page_t m)
417 if (m->wire_count == 0)
423 * SWP_SIZECHECK() - update swap_pager_full indication
425 * update the swap_pager_almost_full indication and warn when we are
426 * about to run out of swap space, using lowat/hiwat hysteresis.
428 * Clear swap_pager_full ( task killing ) indication when lowat is met.
430 * No restrictions on call
431 * This routine may not block.
437 if (swap_pager_avail < nswap_lowat) {
438 if (swap_pager_almost_full == 0) {
439 printf("swap_pager: out of swap space\n");
440 swap_pager_almost_full = 1;
444 if (swap_pager_avail > nswap_hiwat)
445 swap_pager_almost_full = 0;
450 * SWP_PAGER_HASH() - hash swap meta data
452 * This is an helper function which hashes the swapblk given
453 * the object and page index. It returns a pointer to a pointer
454 * to the object, or a pointer to a NULL pointer if it could not
457 static struct swblock **
458 swp_pager_hash(vm_object_t object, vm_pindex_t index)
460 struct swblock **pswap;
461 struct swblock *swap;
463 index &= ~(vm_pindex_t)SWAP_META_MASK;
464 pswap = &swhash[(index ^ (int)(intptr_t)object) & swhash_mask];
465 while ((swap = *pswap) != NULL) {
466 if (swap->swb_object == object &&
467 swap->swb_index == index
471 pswap = &swap->swb_hnext;
477 * SWAP_PAGER_INIT() - initialize the swap pager!
479 * Expected to be started from system init. NOTE: This code is run
480 * before much else so be careful what you depend on. Most of the VM
481 * system has yet to be initialized at this point.
484 swap_pager_init(void)
487 * Initialize object lists
491 for (i = 0; i < NOBJLISTS; ++i)
492 TAILQ_INIT(&swap_pager_object_list[i]);
493 mtx_init(&sw_alloc_mtx, "swap_pager list", NULL, MTX_DEF);
494 mtx_init(&sw_dev_mtx, "swapdev", NULL, MTX_DEF);
495 sx_init(&sw_alloc_sx, "swspsx");
499 * SWAP_PAGER_SWAP_INIT() - swap pager initialization from pageout process
501 * Expected to be started from pageout process once, prior to entering
505 swap_pager_swap_init(void)
510 * Number of in-transit swap bp operations. Don't
511 * exhaust the pbufs completely. Make sure we
512 * initialize workable values (0 will work for hysteresis
513 * but it isn't very efficient).
515 * The nsw_cluster_max is constrained by the bp->b_pages[]
516 * array (MAXPHYS/PAGE_SIZE) and our locally defined
517 * MAX_PAGEOUT_CLUSTER. Also be aware that swap ops are
518 * constrained by the swap device interleave stripe size.
520 * Currently we hardwire nsw_wcount_async to 4. This limit is
521 * designed to prevent other I/O from having high latencies due to
522 * our pageout I/O. The value 4 works well for one or two active swap
523 * devices but is probably a little low if you have more. Even so,
524 * a higher value would probably generate only a limited improvement
525 * with three or four active swap devices since the system does not
526 * typically have to pageout at extreme bandwidths. We will want
527 * at least 2 per swap devices, and 4 is a pretty good value if you
528 * have one NFS swap device due to the command/ack latency over NFS.
529 * So it all works out pretty well.
531 nsw_cluster_max = min((MAXPHYS/PAGE_SIZE), MAX_PAGEOUT_CLUSTER);
534 nsw_rcount = (nswbuf + 1) / 2;
535 nsw_wcount_sync = (nswbuf + 3) / 4;
536 nsw_wcount_async = 4;
537 nsw_wcount_async_max = nsw_wcount_async;
538 mtx_unlock(&pbuf_mtx);
541 * Initialize our zone. Right now I'm just guessing on the number
542 * we need based on the number of pages in the system. Each swblock
543 * can hold 32 pages, so this is probably overkill. This reservation
544 * is typically limited to around 32MB by default.
546 n = cnt.v_page_count / 2;
547 if (maxswzone && n > maxswzone / sizeof(struct swblock))
548 n = maxswzone / sizeof(struct swblock);
550 swap_zone = uma_zcreate("SWAPMETA", sizeof(struct swblock), NULL, NULL,
551 NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE | UMA_ZONE_VM);
552 if (swap_zone == NULL)
553 panic("failed to create swap_zone.");
555 if (uma_zone_reserve_kva(swap_zone, n))
558 * if the allocation failed, try a zone two thirds the
559 * size of the previous attempt.
564 printf("Swap zone entries reduced from %lu to %lu.\n", n2, n);
565 swap_maxpages = n * SWAP_META_PAGES;
566 swzone = n * sizeof(struct swblock);
570 * Initialize our meta-data hash table. The swapper does not need to
571 * be quite as efficient as the VM system, so we do not use an
572 * oversized hash table.
574 * n: size of hash table, must be power of 2
575 * swhash_mask: hash table index mask
577 for (n = 1; n < n2 / 8; n *= 2)
579 swhash = malloc(sizeof(struct swblock *) * n, M_VMPGDATA, M_WAITOK | M_ZERO);
581 mtx_init(&swhash_mtx, "swap_pager swhash", NULL, MTX_DEF);
585 * SWAP_PAGER_ALLOC() - allocate a new OBJT_SWAP VM object and instantiate
586 * its metadata structures.
588 * This routine is called from the mmap and fork code to create a new
589 * OBJT_SWAP object. We do this by creating an OBJT_DEFAULT object
590 * and then converting it with swp_pager_meta_build().
592 * This routine may block in vm_object_allocate() and create a named
593 * object lookup race, so we must interlock.
598 swap_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot,
599 vm_ooffset_t offset, struct ucred *cred)
604 pindex = OFF_TO_IDX(offset + PAGE_MASK + size);
608 * Reference existing named region or allocate new one. There
609 * should not be a race here against swp_pager_meta_build()
610 * as called from vm_page_remove() in regards to the lookup
613 sx_xlock(&sw_alloc_sx);
614 object = vm_pager_object_lookup(NOBJLIST(handle), handle);
615 if (object == NULL) {
617 if (!swap_reserve_by_cred(size, cred)) {
618 sx_xunlock(&sw_alloc_sx);
624 object = vm_object_allocate(OBJT_DEFAULT, pindex);
625 VM_OBJECT_WLOCK(object);
626 object->handle = handle;
629 object->charge = size;
631 swp_pager_meta_build(object, 0, SWAPBLK_NONE);
632 VM_OBJECT_WUNLOCK(object);
634 sx_xunlock(&sw_alloc_sx);
638 if (!swap_reserve_by_cred(size, cred))
642 object = vm_object_allocate(OBJT_DEFAULT, pindex);
643 VM_OBJECT_WLOCK(object);
646 object->charge = size;
648 swp_pager_meta_build(object, 0, SWAPBLK_NONE);
649 VM_OBJECT_WUNLOCK(object);
655 * SWAP_PAGER_DEALLOC() - remove swap metadata from object
657 * The swap backing for the object is destroyed. The code is
658 * designed such that we can reinstantiate it later, but this
659 * routine is typically called only when the entire object is
660 * about to be destroyed.
662 * The object must be locked.
665 swap_pager_dealloc(vm_object_t object)
669 * Remove from list right away so lookups will fail if we block for
670 * pageout completion.
672 if (object->handle != NULL) {
673 mtx_lock(&sw_alloc_mtx);
674 TAILQ_REMOVE(NOBJLIST(object->handle), object, pager_object_list);
675 mtx_unlock(&sw_alloc_mtx);
678 VM_OBJECT_ASSERT_WLOCKED(object);
679 vm_object_pip_wait(object, "swpdea");
682 * Free all remaining metadata. We only bother to free it from
683 * the swap meta data. We do not attempt to free swapblk's still
684 * associated with vm_page_t's for this object. We do not care
685 * if paging is still in progress on some objects.
687 swp_pager_meta_free_all(object);
688 object->handle = NULL;
689 object->type = OBJT_DEAD;
692 /************************************************************************
693 * SWAP PAGER BITMAP ROUTINES *
694 ************************************************************************/
697 * SWP_PAGER_GETSWAPSPACE() - allocate raw swap space
699 * Allocate swap for the requested number of pages. The starting
700 * swap block number (a page index) is returned or SWAPBLK_NONE
701 * if the allocation failed.
703 * Also has the side effect of advising that somebody made a mistake
704 * when they configured swap and didn't configure enough.
706 * This routine may not sleep.
708 * We allocate in round-robin fashion from the configured devices.
711 swp_pager_getswapspace(int npages)
718 mtx_lock(&sw_dev_mtx);
720 for (i = 0; i < nswapdev; i++) {
722 sp = TAILQ_FIRST(&swtailq);
723 if (!(sp->sw_flags & SW_CLOSING)) {
724 blk = blist_alloc(sp->sw_blist, npages);
725 if (blk != SWAPBLK_NONE) {
727 sp->sw_used += npages;
728 swap_pager_avail -= npages;
730 swdevhd = TAILQ_NEXT(sp, sw_list);
734 sp = TAILQ_NEXT(sp, sw_list);
736 if (swap_pager_full != 2) {
737 printf("swap_pager_getswapspace(%d): failed\n", npages);
739 swap_pager_almost_full = 1;
743 mtx_unlock(&sw_dev_mtx);
748 swp_pager_isondev(daddr_t blk, struct swdevt *sp)
751 return (blk >= sp->sw_first && blk < sp->sw_end);
755 swp_pager_strategy(struct buf *bp)
759 mtx_lock(&sw_dev_mtx);
760 TAILQ_FOREACH(sp, &swtailq, sw_list) {
761 if (bp->b_blkno >= sp->sw_first && bp->b_blkno < sp->sw_end) {
762 mtx_unlock(&sw_dev_mtx);
763 if ((sp->sw_flags & SW_UNMAPPED) != 0 &&
764 unmapped_buf_allowed) {
765 bp->b_kvaalloc = bp->b_data;
766 bp->b_data = unmapped_buf;
767 bp->b_kvabase = unmapped_buf;
769 bp->b_flags |= B_UNMAPPED;
771 pmap_qenter((vm_offset_t)bp->b_data,
772 &bp->b_pages[0], bp->b_bcount / PAGE_SIZE);
774 sp->sw_strategy(bp, sp);
778 panic("Swapdev not found");
783 * SWP_PAGER_FREESWAPSPACE() - free raw swap space
785 * This routine returns the specified swap blocks back to the bitmap.
787 * This routine may not sleep.
790 swp_pager_freeswapspace(daddr_t blk, int npages)
794 mtx_lock(&sw_dev_mtx);
795 TAILQ_FOREACH(sp, &swtailq, sw_list) {
796 if (blk >= sp->sw_first && blk < sp->sw_end) {
797 sp->sw_used -= npages;
799 * If we are attempting to stop swapping on
800 * this device, we don't want to mark any
801 * blocks free lest they be reused.
803 if ((sp->sw_flags & SW_CLOSING) == 0) {
804 blist_free(sp->sw_blist, blk - sp->sw_first,
806 swap_pager_avail += npages;
809 mtx_unlock(&sw_dev_mtx);
813 panic("Swapdev not found");
817 * SWAP_PAGER_FREESPACE() - frees swap blocks associated with a page
818 * range within an object.
820 * This is a globally accessible routine.
822 * This routine removes swapblk assignments from swap metadata.
824 * The external callers of this routine typically have already destroyed
825 * or renamed vm_page_t's associated with this range in the object so
828 * The object must be locked.
831 swap_pager_freespace(vm_object_t object, vm_pindex_t start, vm_size_t size)
834 swp_pager_meta_free(object, start, size);
838 * SWAP_PAGER_RESERVE() - reserve swap blocks in object
840 * Assigns swap blocks to the specified range within the object. The
841 * swap blocks are not zeroed. Any previous swap assignment is destroyed.
843 * Returns 0 on success, -1 on failure.
846 swap_pager_reserve(vm_object_t object, vm_pindex_t start, vm_size_t size)
849 daddr_t blk = SWAPBLK_NONE;
850 vm_pindex_t beg = start; /* save start index */
852 VM_OBJECT_WLOCK(object);
856 while ((blk = swp_pager_getswapspace(n)) == SWAPBLK_NONE) {
859 swp_pager_meta_free(object, beg, start - beg);
860 VM_OBJECT_WUNLOCK(object);
865 swp_pager_meta_build(object, start, blk);
871 swp_pager_meta_free(object, start, n);
872 VM_OBJECT_WUNLOCK(object);
877 * SWAP_PAGER_COPY() - copy blocks from source pager to destination pager
878 * and destroy the source.
880 * Copy any valid swapblks from the source to the destination. In
881 * cases where both the source and destination have a valid swapblk,
882 * we keep the destination's.
884 * This routine is allowed to sleep. It may sleep allocating metadata
885 * indirectly through swp_pager_meta_build() or if paging is still in
886 * progress on the source.
888 * The source object contains no vm_page_t's (which is just as well)
890 * The source object is of type OBJT_SWAP.
892 * The source and destination objects must be locked.
893 * Both object locks may temporarily be released.
896 swap_pager_copy(vm_object_t srcobject, vm_object_t dstobject,
897 vm_pindex_t offset, int destroysource)
901 VM_OBJECT_ASSERT_WLOCKED(srcobject);
902 VM_OBJECT_ASSERT_WLOCKED(dstobject);
905 * If destroysource is set, we remove the source object from the
906 * swap_pager internal queue now.
909 if (srcobject->handle != NULL) {
910 mtx_lock(&sw_alloc_mtx);
912 NOBJLIST(srcobject->handle),
916 mtx_unlock(&sw_alloc_mtx);
921 * transfer source to destination.
923 for (i = 0; i < dstobject->size; ++i) {
927 * Locate (without changing) the swapblk on the destination,
928 * unless it is invalid in which case free it silently, or
929 * if the destination is a resident page, in which case the
930 * source is thrown away.
932 dstaddr = swp_pager_meta_ctl(dstobject, i, 0);
934 if (dstaddr == SWAPBLK_NONE) {
936 * Destination has no swapblk and is not resident,
941 srcaddr = swp_pager_meta_ctl(
947 if (srcaddr != SWAPBLK_NONE) {
949 * swp_pager_meta_build() can sleep.
951 vm_object_pip_add(srcobject, 1);
952 VM_OBJECT_WUNLOCK(srcobject);
953 vm_object_pip_add(dstobject, 1);
954 swp_pager_meta_build(dstobject, i, srcaddr);
955 vm_object_pip_wakeup(dstobject);
956 VM_OBJECT_WLOCK(srcobject);
957 vm_object_pip_wakeup(srcobject);
961 * Destination has valid swapblk or it is represented
962 * by a resident page. We destroy the sourceblock.
965 swp_pager_meta_ctl(srcobject, i + offset, SWM_FREE);
970 * Free left over swap blocks in source.
972 * We have to revert the type to OBJT_DEFAULT so we do not accidently
973 * double-remove the object from the swap queues.
976 swp_pager_meta_free_all(srcobject);
978 * Reverting the type is not necessary, the caller is going
979 * to destroy srcobject directly, but I'm doing it here
980 * for consistency since we've removed the object from its
983 srcobject->type = OBJT_DEFAULT;
988 * SWAP_PAGER_HASPAGE() - determine if we have good backing store for
989 * the requested page.
991 * We determine whether good backing store exists for the requested
992 * page and return TRUE if it does, FALSE if it doesn't.
994 * If TRUE, we also try to determine how much valid, contiguous backing
995 * store exists before and after the requested page within a reasonable
996 * distance. We do not try to restrict it to the swap device stripe
997 * (that is handled in getpages/putpages). It probably isn't worth
1001 swap_pager_haspage(vm_object_t object, vm_pindex_t pindex, int *before, int *after)
1005 VM_OBJECT_ASSERT_LOCKED(object);
1007 * do we have good backing store at the requested index ?
1009 blk0 = swp_pager_meta_ctl(object, pindex, 0);
1011 if (blk0 == SWAPBLK_NONE) {
1020 * find backwards-looking contiguous good backing store
1022 if (before != NULL) {
1025 for (i = 1; i < (SWB_NPAGES/2); ++i) {
1030 blk = swp_pager_meta_ctl(object, pindex - i, 0);
1031 if (blk != blk0 - i)
1038 * find forward-looking contiguous good backing store
1040 if (after != NULL) {
1043 for (i = 1; i < (SWB_NPAGES/2); ++i) {
1046 blk = swp_pager_meta_ctl(object, pindex + i, 0);
1047 if (blk != blk0 + i)
1056 * SWAP_PAGER_PAGE_UNSWAPPED() - remove swap backing store related to page
1058 * This removes any associated swap backing store, whether valid or
1059 * not, from the page.
1061 * This routine is typically called when a page is made dirty, at
1062 * which point any associated swap can be freed. MADV_FREE also
1063 * calls us in a special-case situation
1065 * NOTE!!! If the page is clean and the swap was valid, the caller
1066 * should make the page dirty before calling this routine. This routine
1067 * does NOT change the m->dirty status of the page. Also: MADV_FREE
1070 * This routine may not sleep.
1072 * The object containing the page must be locked.
1075 swap_pager_unswapped(vm_page_t m)
1078 swp_pager_meta_ctl(m->object, m->pindex, SWM_FREE);
1082 * SWAP_PAGER_GETPAGES() - bring pages in from swap
1084 * Attempt to retrieve (m, count) pages from backing store, but make
1085 * sure we retrieve at least m[reqpage]. We try to load in as large
1086 * a chunk surrounding m[reqpage] as is contiguous in swap and which
1087 * belongs to the same object.
1089 * The code is designed for asynchronous operation and
1090 * immediate-notification of 'reqpage' but tends not to be
1091 * used that way. Please do not optimize-out this algorithmic
1092 * feature, I intend to improve on it in the future.
1094 * The parent has a single vm_object_pip_add() reference prior to
1095 * calling us and we should return with the same.
1097 * The parent has BUSY'd the pages. We should return with 'm'
1098 * left busy, but the others adjusted.
1101 swap_pager_getpages(vm_object_t object, vm_page_t *m, int count, int reqpage)
1111 KASSERT(mreq->object == object,
1112 ("swap_pager_getpages: object mismatch %p/%p",
1113 object, mreq->object));
1116 * Calculate range to retrieve. The pages have already been assigned
1117 * their swapblks. We require a *contiguous* range but we know it to
1118 * not span devices. If we do not supply it, bad things
1119 * happen. Note that blk, iblk & jblk can be SWAPBLK_NONE, but the
1120 * loops are set up such that the case(s) are handled implicitly.
1122 * The swp_*() calls must be made with the object locked.
1124 blk = swp_pager_meta_ctl(mreq->object, mreq->pindex, 0);
1126 for (i = reqpage - 1; i >= 0; --i) {
1129 iblk = swp_pager_meta_ctl(m[i]->object, m[i]->pindex, 0);
1130 if (blk != iblk + (reqpage - i))
1135 for (j = reqpage + 1; j < count; ++j) {
1138 jblk = swp_pager_meta_ctl(m[j]->object, m[j]->pindex, 0);
1139 if (blk != jblk - (j - reqpage))
1144 * free pages outside our collection range. Note: we never free
1145 * mreq, it must remain busy throughout.
1147 if (0 < i || j < count) {
1150 for (k = 0; k < i; ++k)
1151 swp_pager_free_nrpage(m[k]);
1152 for (k = j; k < count; ++k)
1153 swp_pager_free_nrpage(m[k]);
1157 * Return VM_PAGER_FAIL if we have nothing to do. Return mreq
1158 * still busy, but the others unbusied.
1160 if (blk == SWAPBLK_NONE)
1161 return (VM_PAGER_FAIL);
1164 * Getpbuf() can sleep.
1166 VM_OBJECT_WUNLOCK(object);
1168 * Get a swap buffer header to perform the IO
1170 bp = getpbuf(&nsw_rcount);
1171 bp->b_flags |= B_PAGING;
1173 bp->b_iocmd = BIO_READ;
1174 bp->b_iodone = swp_pager_async_iodone;
1175 bp->b_rcred = crhold(thread0.td_ucred);
1176 bp->b_wcred = crhold(thread0.td_ucred);
1177 bp->b_blkno = blk - (reqpage - i);
1178 bp->b_bcount = PAGE_SIZE * (j - i);
1179 bp->b_bufsize = PAGE_SIZE * (j - i);
1180 bp->b_pager.pg_reqpage = reqpage - i;
1182 VM_OBJECT_WLOCK(object);
1186 for (k = i; k < j; ++k) {
1187 bp->b_pages[k - i] = m[k];
1188 m[k]->oflags |= VPO_SWAPINPROG;
1191 bp->b_npages = j - i;
1193 PCPU_INC(cnt.v_swapin);
1194 PCPU_ADD(cnt.v_swappgsin, bp->b_npages);
1197 * We still hold the lock on mreq, and our automatic completion routine
1198 * does not remove it.
1200 vm_object_pip_add(object, bp->b_npages);
1201 VM_OBJECT_WUNLOCK(object);
1204 * perform the I/O. NOTE!!! bp cannot be considered valid after
1205 * this point because we automatically release it on completion.
1206 * Instead, we look at the one page we are interested in which we
1207 * still hold a lock on even through the I/O completion.
1209 * The other pages in our m[] array are also released on completion,
1210 * so we cannot assume they are valid anymore either.
1212 * NOTE: b_blkno is destroyed by the call to swapdev_strategy
1215 swp_pager_strategy(bp);
1218 * wait for the page we want to complete. VPO_SWAPINPROG is always
1219 * cleared on completion. If an I/O error occurs, SWAPBLK_NONE
1220 * is set in the meta-data.
1222 VM_OBJECT_WLOCK(object);
1223 while ((mreq->oflags & VPO_SWAPINPROG) != 0) {
1224 mreq->oflags |= VPO_SWAPSLEEP;
1225 PCPU_INC(cnt.v_intrans);
1226 if (VM_OBJECT_SLEEP(object, &object->paging_in_progress, PSWP,
1227 "swread", hz * 20)) {
1229 "swap_pager: indefinite wait buffer: bufobj: %p, blkno: %jd, size: %ld\n",
1230 bp->b_bufobj, (intmax_t)bp->b_blkno, bp->b_bcount);
1235 * mreq is left busied after completion, but all the other pages
1236 * are freed. If we had an unrecoverable read error the page will
1239 if (mreq->valid != VM_PAGE_BITS_ALL) {
1240 return (VM_PAGER_ERROR);
1242 return (VM_PAGER_OK);
1246 * A final note: in a low swap situation, we cannot deallocate swap
1247 * and mark a page dirty here because the caller is likely to mark
1248 * the page clean when we return, causing the page to possibly revert
1249 * to all-zero's later.
1254 * swap_pager_putpages:
1256 * Assign swap (if necessary) and initiate I/O on the specified pages.
1258 * We support both OBJT_DEFAULT and OBJT_SWAP objects. DEFAULT objects
1259 * are automatically converted to SWAP objects.
1261 * In a low memory situation we may block in VOP_STRATEGY(), but the new
1262 * vm_page reservation system coupled with properly written VFS devices
1263 * should ensure that no low-memory deadlock occurs. This is an area
1266 * The parent has N vm_object_pip_add() references prior to
1267 * calling us and will remove references for rtvals[] that are
1268 * not set to VM_PAGER_PEND. We need to remove the rest on I/O
1271 * The parent has soft-busy'd the pages it passes us and will unbusy
1272 * those whos rtvals[] entry is not set to VM_PAGER_PEND on return.
1273 * We need to unbusy the rest on I/O completion.
1276 swap_pager_putpages(vm_object_t object, vm_page_t *m, int count,
1277 int flags, int *rtvals)
1282 if (count && m[0]->object != object) {
1283 panic("swap_pager_putpages: object mismatch %p/%p",
1292 * Turn object into OBJT_SWAP
1293 * check for bogus sysops
1294 * force sync if not pageout process
1296 if (object->type != OBJT_SWAP)
1297 swp_pager_meta_build(object, 0, SWAPBLK_NONE);
1298 VM_OBJECT_WUNLOCK(object);
1301 if (curproc != pageproc)
1304 sync = (flags & VM_PAGER_PUT_SYNC) != 0;
1309 * Update nsw parameters from swap_async_max sysctl values.
1310 * Do not let the sysop crash the machine with bogus numbers.
1312 mtx_lock(&pbuf_mtx);
1313 if (swap_async_max != nsw_wcount_async_max) {
1319 if ((n = swap_async_max) > nswbuf / 2)
1326 * Adjust difference ( if possible ). If the current async
1327 * count is too low, we may not be able to make the adjustment
1330 n -= nsw_wcount_async_max;
1331 if (nsw_wcount_async + n >= 0) {
1332 nsw_wcount_async += n;
1333 nsw_wcount_async_max += n;
1334 wakeup(&nsw_wcount_async);
1337 mtx_unlock(&pbuf_mtx);
1342 * Assign swap blocks and issue I/O. We reallocate swap on the fly.
1343 * The page is left dirty until the pageout operation completes
1346 for (i = 0; i < count; i += n) {
1352 * Maximum I/O size is limited by a number of factors.
1354 n = min(BLIST_MAX_ALLOC, count - i);
1355 n = min(n, nsw_cluster_max);
1358 * Get biggest block of swap we can. If we fail, fall
1359 * back and try to allocate a smaller block. Don't go
1360 * overboard trying to allocate space if it would overly
1364 (blk = swp_pager_getswapspace(n)) == SWAPBLK_NONE &&
1369 if (blk == SWAPBLK_NONE) {
1370 for (j = 0; j < n; ++j)
1371 rtvals[i+j] = VM_PAGER_FAIL;
1376 * All I/O parameters have been satisfied, build the I/O
1377 * request and assign the swap space.
1380 bp = getpbuf(&nsw_wcount_sync);
1382 bp = getpbuf(&nsw_wcount_async);
1383 bp->b_flags = B_ASYNC;
1385 bp->b_flags |= B_PAGING;
1386 bp->b_iocmd = BIO_WRITE;
1388 bp->b_rcred = crhold(thread0.td_ucred);
1389 bp->b_wcred = crhold(thread0.td_ucred);
1390 bp->b_bcount = PAGE_SIZE * n;
1391 bp->b_bufsize = PAGE_SIZE * n;
1394 VM_OBJECT_WLOCK(object);
1395 for (j = 0; j < n; ++j) {
1396 vm_page_t mreq = m[i+j];
1398 swp_pager_meta_build(
1403 MPASS(mreq->dirty == VM_PAGE_BITS_ALL);
1404 rtvals[i+j] = VM_PAGER_OK;
1406 mreq->oflags |= VPO_SWAPINPROG;
1407 bp->b_pages[j] = mreq;
1409 VM_OBJECT_WUNLOCK(object);
1412 * Must set dirty range for NFS to work.
1415 bp->b_dirtyend = bp->b_bcount;
1417 PCPU_INC(cnt.v_swapout);
1418 PCPU_ADD(cnt.v_swappgsout, bp->b_npages);
1423 * NOTE: b_blkno is destroyed by the call to swapdev_strategy
1425 if (sync == FALSE) {
1426 bp->b_iodone = swp_pager_async_iodone;
1428 swp_pager_strategy(bp);
1430 for (j = 0; j < n; ++j)
1431 rtvals[i+j] = VM_PAGER_PEND;
1432 /* restart outter loop */
1439 * NOTE: b_blkno is destroyed by the call to swapdev_strategy
1441 bp->b_iodone = bdone;
1442 swp_pager_strategy(bp);
1445 * Wait for the sync I/O to complete, then update rtvals.
1446 * We just set the rtvals[] to VM_PAGER_PEND so we can call
1447 * our async completion routine at the end, thus avoiding a
1450 bwait(bp, PVM, "swwrt");
1451 for (j = 0; j < n; ++j)
1452 rtvals[i+j] = VM_PAGER_PEND;
1454 * Now that we are through with the bp, we can call the
1455 * normal async completion, which frees everything up.
1457 swp_pager_async_iodone(bp);
1459 VM_OBJECT_WLOCK(object);
1463 * swp_pager_async_iodone:
1465 * Completion routine for asynchronous reads and writes from/to swap.
1466 * Also called manually by synchronous code to finish up a bp.
1468 * This routine may not sleep.
1471 swp_pager_async_iodone(struct buf *bp)
1474 vm_object_t object = NULL;
1479 if (bp->b_ioflags & BIO_ERROR) {
1481 "swap_pager: I/O error - %s failed; blkno %ld,"
1482 "size %ld, error %d\n",
1483 ((bp->b_iocmd == BIO_READ) ? "pagein" : "pageout"),
1491 * remove the mapping for kernel virtual
1493 if ((bp->b_flags & B_UNMAPPED) != 0) {
1494 bp->b_data = bp->b_kvaalloc;
1495 bp->b_kvabase = bp->b_kvaalloc;
1496 bp->b_flags &= ~B_UNMAPPED;
1498 pmap_qremove((vm_offset_t)bp->b_data, bp->b_npages);
1501 object = bp->b_pages[0]->object;
1502 VM_OBJECT_WLOCK(object);
1506 * cleanup pages. If an error occurs writing to swap, we are in
1507 * very serious trouble. If it happens to be a disk error, though,
1508 * we may be able to recover by reassigning the swap later on. So
1509 * in this case we remove the m->swapblk assignment for the page
1510 * but do not free it in the rlist. The errornous block(s) are thus
1511 * never reallocated as swap. Redirty the page and continue.
1513 for (i = 0; i < bp->b_npages; ++i) {
1514 vm_page_t m = bp->b_pages[i];
1516 m->oflags &= ~VPO_SWAPINPROG;
1517 if (m->oflags & VPO_SWAPSLEEP) {
1518 m->oflags &= ~VPO_SWAPSLEEP;
1519 wakeup(&object->paging_in_progress);
1522 if (bp->b_ioflags & BIO_ERROR) {
1524 * If an error occurs I'd love to throw the swapblk
1525 * away without freeing it back to swapspace, so it
1526 * can never be used again. But I can't from an
1529 if (bp->b_iocmd == BIO_READ) {
1531 * When reading, reqpage needs to stay
1532 * locked for the parent, but all other
1533 * pages can be freed. We still want to
1534 * wakeup the parent waiting on the page,
1535 * though. ( also: pg_reqpage can be -1 and
1536 * not match anything ).
1538 * We have to wake specifically requested pages
1539 * up too because we cleared VPO_SWAPINPROG and
1540 * someone may be waiting for that.
1542 * NOTE: for reads, m->dirty will probably
1543 * be overridden by the original caller of
1544 * getpages so don't play cute tricks here.
1547 if (i != bp->b_pager.pg_reqpage)
1548 swp_pager_free_nrpage(m);
1555 * If i == bp->b_pager.pg_reqpage, do not wake
1556 * the page up. The caller needs to.
1560 * If a write error occurs, reactivate page
1561 * so it doesn't clog the inactive list,
1562 * then finish the I/O.
1566 vm_page_activate(m);
1570 } else if (bp->b_iocmd == BIO_READ) {
1572 * NOTE: for reads, m->dirty will probably be
1573 * overridden by the original caller of getpages so
1574 * we cannot set them in order to free the underlying
1575 * swap in a low-swap situation. I don't think we'd
1576 * want to do that anyway, but it was an optimization
1577 * that existed in the old swapper for a time before
1578 * it got ripped out due to precisely this problem.
1580 * If not the requested page then deactivate it.
1582 * Note that the requested page, reqpage, is left
1583 * busied, but we still have to wake it up. The
1584 * other pages are released (unbusied) by
1585 * vm_page_xunbusy().
1587 KASSERT(!pmap_page_is_mapped(m),
1588 ("swp_pager_async_iodone: page %p is mapped", m));
1589 m->valid = VM_PAGE_BITS_ALL;
1590 KASSERT(m->dirty == 0,
1591 ("swp_pager_async_iodone: page %p is dirty", m));
1594 * We have to wake specifically requested pages
1595 * up too because we cleared VPO_SWAPINPROG and
1596 * could be waiting for it in getpages. However,
1597 * be sure to not unbusy getpages specifically
1598 * requested page - getpages expects it to be
1601 if (i != bp->b_pager.pg_reqpage) {
1603 vm_page_deactivate(m);
1613 * For write success, clear the dirty
1614 * status, then finish the I/O ( which decrements the
1615 * busy count and possibly wakes waiter's up ).
1617 KASSERT(!pmap_page_is_write_mapped(m),
1618 ("swp_pager_async_iodone: page %p is not write"
1622 if (vm_page_count_severe()) {
1624 vm_page_try_to_cache(m);
1631 * adjust pip. NOTE: the original parent may still have its own
1632 * pip refs on the object.
1634 if (object != NULL) {
1635 vm_object_pip_wakeupn(object, bp->b_npages);
1636 VM_OBJECT_WUNLOCK(object);
1640 * swapdev_strategy() manually sets b_vp and b_bufobj before calling
1641 * bstrategy(). Set them back to NULL now we're done with it, or we'll
1642 * trigger a KASSERT in relpbuf().
1646 bp->b_bufobj = NULL;
1649 * release the physical I/O buffer
1653 ((bp->b_iocmd == BIO_READ) ? &nsw_rcount :
1654 ((bp->b_flags & B_ASYNC) ?
1663 * swap_pager_isswapped:
1665 * Return 1 if at least one page in the given object is paged
1666 * out to the given swap device.
1668 * This routine may not sleep.
1671 swap_pager_isswapped(vm_object_t object, struct swdevt *sp)
1677 VM_OBJECT_ASSERT_WLOCKED(object);
1678 if (object->type != OBJT_SWAP)
1681 mtx_lock(&swhash_mtx);
1682 for (bcount = 0; bcount < object->un_pager.swp.swp_bcount; bcount++) {
1683 struct swblock *swap;
1685 if ((swap = *swp_pager_hash(object, index)) != NULL) {
1686 for (i = 0; i < SWAP_META_PAGES; ++i) {
1687 if (swp_pager_isondev(swap->swb_pages[i], sp)) {
1688 mtx_unlock(&swhash_mtx);
1693 index += SWAP_META_PAGES;
1695 mtx_unlock(&swhash_mtx);
1700 * SWP_PAGER_FORCE_PAGEIN() - force a swap block to be paged in
1702 * This routine dissociates the page at the given index within a
1703 * swap block from its backing store, paging it in if necessary.
1704 * If the page is paged in, it is placed in the inactive queue,
1705 * since it had its backing store ripped out from under it.
1706 * We also attempt to swap in all other pages in the swap block,
1707 * we only guarantee that the one at the specified index is
1710 * XXX - The code to page the whole block in doesn't work, so we
1711 * revert to the one-by-one behavior for now. Sigh.
1714 swp_pager_force_pagein(vm_object_t object, vm_pindex_t pindex)
1718 vm_object_pip_add(object, 1);
1719 m = vm_page_grab(object, pindex, VM_ALLOC_NORMAL);
1720 if (m->valid == VM_PAGE_BITS_ALL) {
1721 vm_object_pip_subtract(object, 1);
1724 vm_page_activate(m);
1727 vm_pager_page_unswapped(m);
1731 if (swap_pager_getpages(object, &m, 1, 0) != VM_PAGER_OK)
1732 panic("swap_pager_force_pagein: read from swap failed");/*XXX*/
1733 vm_object_pip_subtract(object, 1);
1736 vm_page_deactivate(m);
1739 vm_pager_page_unswapped(m);
1743 * swap_pager_swapoff:
1745 * Page in all of the pages that have been paged out to the
1746 * given device. The corresponding blocks in the bitmap must be
1747 * marked as allocated and the device must be flagged SW_CLOSING.
1748 * There may be no processes swapped out to the device.
1750 * This routine may block.
1753 swap_pager_swapoff(struct swdevt *sp)
1755 struct swblock *swap;
1756 vm_object_t locked_obj, object;
1765 mtx_lock(&swhash_mtx);
1766 for (i = 0; i <= swhash_mask; i++) { /* '<=' is correct here */
1768 for (swap = swhash[i]; swap != NULL; swap = swap->swb_hnext) {
1769 object = swap->swb_object;
1770 pindex = swap->swb_index;
1771 for (j = 0; j < SWAP_META_PAGES; ++j) {
1772 if (!swp_pager_isondev(swap->swb_pages[j], sp))
1774 if (locked_obj != object) {
1775 if (locked_obj != NULL)
1776 VM_OBJECT_WUNLOCK(locked_obj);
1777 locked_obj = object;
1778 if (!VM_OBJECT_TRYWLOCK(object)) {
1779 mtx_unlock(&swhash_mtx);
1780 /* Depends on type-stability. */
1781 VM_OBJECT_WLOCK(object);
1782 mtx_lock(&swhash_mtx);
1786 MPASS(locked_obj == object);
1787 mtx_unlock(&swhash_mtx);
1788 swp_pager_force_pagein(object, pindex + j);
1789 mtx_lock(&swhash_mtx);
1794 mtx_unlock(&swhash_mtx);
1795 if (locked_obj != NULL) {
1796 VM_OBJECT_WUNLOCK(locked_obj);
1801 * Objects may be locked or paging to the device being
1802 * removed, so we will miss their pages and need to
1803 * make another pass. We have marked this device as
1804 * SW_CLOSING, so the activity should finish soon.
1807 if (retries > 100) {
1808 panic("swapoff: failed to locate %d swap blocks",
1811 pause("swpoff", hz / 20);
1816 /************************************************************************
1818 ************************************************************************
1820 * These routines manipulate the swap metadata stored in the
1823 * Swap metadata is implemented with a global hash and not directly
1824 * linked into the object. Instead the object simply contains
1825 * appropriate tracking counters.
1829 * SWP_PAGER_META_BUILD() - add swap block to swap meta data for object
1831 * We first convert the object to a swap object if it is a default
1834 * The specified swapblk is added to the object's swap metadata. If
1835 * the swapblk is not valid, it is freed instead. Any previously
1836 * assigned swapblk is freed.
1839 swp_pager_meta_build(vm_object_t object, vm_pindex_t pindex, daddr_t swapblk)
1841 static volatile int exhausted;
1842 struct swblock *swap;
1843 struct swblock **pswap;
1846 VM_OBJECT_ASSERT_WLOCKED(object);
1848 * Convert default object to swap object if necessary
1850 if (object->type != OBJT_SWAP) {
1851 object->type = OBJT_SWAP;
1852 object->un_pager.swp.swp_bcount = 0;
1854 if (object->handle != NULL) {
1855 mtx_lock(&sw_alloc_mtx);
1857 NOBJLIST(object->handle),
1861 mtx_unlock(&sw_alloc_mtx);
1866 * Locate hash entry. If not found create, but if we aren't adding
1867 * anything just return. If we run out of space in the map we wait
1868 * and, since the hash table may have changed, retry.
1871 mtx_lock(&swhash_mtx);
1872 pswap = swp_pager_hash(object, pindex);
1874 if ((swap = *pswap) == NULL) {
1877 if (swapblk == SWAPBLK_NONE)
1880 swap = *pswap = uma_zalloc(swap_zone, M_NOWAIT |
1881 (curproc == pageproc ? M_USE_RESERVE : 0));
1883 mtx_unlock(&swhash_mtx);
1884 VM_OBJECT_WUNLOCK(object);
1885 if (uma_zone_exhausted(swap_zone)) {
1886 if (atomic_cmpset_int(&exhausted, 0, 1))
1887 printf("swap zone exhausted, "
1888 "increase kern.maxswzone\n");
1889 vm_pageout_oom(VM_OOM_SWAPZ);
1890 pause("swzonex", 10);
1893 VM_OBJECT_WLOCK(object);
1897 if (atomic_cmpset_int(&exhausted, 1, 0))
1898 printf("swap zone ok\n");
1900 swap->swb_hnext = NULL;
1901 swap->swb_object = object;
1902 swap->swb_index = pindex & ~(vm_pindex_t)SWAP_META_MASK;
1903 swap->swb_count = 0;
1905 ++object->un_pager.swp.swp_bcount;
1907 for (i = 0; i < SWAP_META_PAGES; ++i)
1908 swap->swb_pages[i] = SWAPBLK_NONE;
1912 * Delete prior contents of metadata
1914 idx = pindex & SWAP_META_MASK;
1916 if (swap->swb_pages[idx] != SWAPBLK_NONE) {
1917 swp_pager_freeswapspace(swap->swb_pages[idx], 1);
1922 * Enter block into metadata
1924 swap->swb_pages[idx] = swapblk;
1925 if (swapblk != SWAPBLK_NONE)
1928 mtx_unlock(&swhash_mtx);
1932 * SWP_PAGER_META_FREE() - free a range of blocks in the object's swap metadata
1934 * The requested range of blocks is freed, with any associated swap
1935 * returned to the swap bitmap.
1937 * This routine will free swap metadata structures as they are cleaned
1938 * out. This routine does *NOT* operate on swap metadata associated
1939 * with resident pages.
1942 swp_pager_meta_free(vm_object_t object, vm_pindex_t index, daddr_t count)
1945 VM_OBJECT_ASSERT_LOCKED(object);
1946 if (object->type != OBJT_SWAP)
1950 struct swblock **pswap;
1951 struct swblock *swap;
1953 mtx_lock(&swhash_mtx);
1954 pswap = swp_pager_hash(object, index);
1956 if ((swap = *pswap) != NULL) {
1957 daddr_t v = swap->swb_pages[index & SWAP_META_MASK];
1959 if (v != SWAPBLK_NONE) {
1960 swp_pager_freeswapspace(v, 1);
1961 swap->swb_pages[index & SWAP_META_MASK] =
1963 if (--swap->swb_count == 0) {
1964 *pswap = swap->swb_hnext;
1965 uma_zfree(swap_zone, swap);
1966 --object->un_pager.swp.swp_bcount;
1972 int n = SWAP_META_PAGES - (index & SWAP_META_MASK);
1976 mtx_unlock(&swhash_mtx);
1981 * SWP_PAGER_META_FREE_ALL() - destroy all swap metadata associated with object
1983 * This routine locates and destroys all swap metadata associated with
1987 swp_pager_meta_free_all(vm_object_t object)
1989 struct swblock **pswap, *swap;
1994 VM_OBJECT_ASSERT_WLOCKED(object);
1995 if (object->type != OBJT_SWAP)
1999 while (object->un_pager.swp.swp_bcount != 0) {
2000 mtx_lock(&swhash_mtx);
2001 pswap = swp_pager_hash(object, index);
2002 if ((swap = *pswap) != NULL) {
2003 for (i = 0; i < SWAP_META_PAGES; ++i) {
2004 v = swap->swb_pages[i];
2005 if (v != SWAPBLK_NONE) {
2007 swp_pager_freeswapspace(v, 1);
2010 if (swap->swb_count != 0)
2012 "swap_pager_meta_free_all: swb_count != 0");
2013 *pswap = swap->swb_hnext;
2014 uma_zfree(swap_zone, swap);
2015 --object->un_pager.swp.swp_bcount;
2017 mtx_unlock(&swhash_mtx);
2018 index += SWAP_META_PAGES;
2023 * SWP_PAGER_METACTL() - misc control of swap and vm_page_t meta data.
2025 * This routine is capable of looking up, popping, or freeing
2026 * swapblk assignments in the swap meta data or in the vm_page_t.
2027 * The routine typically returns the swapblk being looked-up, or popped,
2028 * or SWAPBLK_NONE if the block was freed, or SWAPBLK_NONE if the block
2029 * was invalid. This routine will automatically free any invalid
2030 * meta-data swapblks.
2032 * It is not possible to store invalid swapblks in the swap meta data
2033 * (other then a literal 'SWAPBLK_NONE'), so we don't bother checking.
2035 * When acting on a busy resident page and paging is in progress, we
2036 * have to wait until paging is complete but otherwise can act on the
2039 * SWM_FREE remove and free swap block from metadata
2040 * SWM_POP remove from meta data but do not free.. pop it out
2043 swp_pager_meta_ctl(vm_object_t object, vm_pindex_t pindex, int flags)
2045 struct swblock **pswap;
2046 struct swblock *swap;
2050 VM_OBJECT_ASSERT_LOCKED(object);
2052 * The meta data only exists of the object is OBJT_SWAP
2053 * and even then might not be allocated yet.
2055 if (object->type != OBJT_SWAP)
2056 return (SWAPBLK_NONE);
2059 mtx_lock(&swhash_mtx);
2060 pswap = swp_pager_hash(object, pindex);
2062 if ((swap = *pswap) != NULL) {
2063 idx = pindex & SWAP_META_MASK;
2064 r1 = swap->swb_pages[idx];
2066 if (r1 != SWAPBLK_NONE) {
2067 if (flags & SWM_FREE) {
2068 swp_pager_freeswapspace(r1, 1);
2071 if (flags & (SWM_FREE|SWM_POP)) {
2072 swap->swb_pages[idx] = SWAPBLK_NONE;
2073 if (--swap->swb_count == 0) {
2074 *pswap = swap->swb_hnext;
2075 uma_zfree(swap_zone, swap);
2076 --object->un_pager.swp.swp_bcount;
2081 mtx_unlock(&swhash_mtx);
2086 * System call swapon(name) enables swapping on device name,
2087 * which must be in the swdevsw. Return EBUSY
2088 * if already swapping on this device.
2090 #ifndef _SYS_SYSPROTO_H_
2091 struct swapon_args {
2101 sys_swapon(struct thread *td, struct swapon_args *uap)
2105 struct nameidata nd;
2108 error = priv_check(td, PRIV_SWAPON);
2113 while (swdev_syscall_active)
2114 tsleep(&swdev_syscall_active, PUSER - 1, "swpon", 0);
2115 swdev_syscall_active = 1;
2118 * Swap metadata may not fit in the KVM if we have physical
2121 if (swap_zone == NULL) {
2126 NDINIT(&nd, LOOKUP, ISOPEN | FOLLOW | AUDITVNODE1, UIO_USERSPACE,
2132 NDFREE(&nd, NDF_ONLY_PNBUF);
2135 if (vn_isdisk(vp, &error)) {
2136 error = swapongeom(td, vp);
2137 } else if (vp->v_type == VREG &&
2138 (vp->v_mount->mnt_vfc->vfc_flags & VFCF_NETWORK) != 0 &&
2139 (error = VOP_GETATTR(vp, &attr, td->td_ucred)) == 0) {
2141 * Allow direct swapping to NFS regular files in the same
2142 * way that nfs_mountroot() sets up diskless swapping.
2144 error = swaponvp(td, vp, attr.va_size / DEV_BSIZE);
2150 swdev_syscall_active = 0;
2151 wakeup_one(&swdev_syscall_active);
2157 * Check that the total amount of swap currently configured does not
2158 * exceed half the theoretical maximum. If it does, print a warning
2159 * message and return -1; otherwise, return 0.
2162 swapon_check_swzone(unsigned long npages)
2164 unsigned long maxpages;
2166 /* absolute maximum we can handle assuming 100% efficiency */
2167 maxpages = uma_zone_get_max(swap_zone) * SWAP_META_PAGES;
2169 /* recommend using no more than half that amount */
2170 if (npages > maxpages / 2) {
2171 printf("warning: total configured swap (%lu pages) "
2172 "exceeds maximum recommended amount (%lu pages).\n",
2173 npages, maxpages / 2);
2174 printf("warning: increase kern.maxswzone "
2175 "or reduce amount of swap.\n");
2182 swaponsomething(struct vnode *vp, void *id, u_long nblks,
2183 sw_strategy_t *strategy, sw_close_t *close, dev_t dev, int flags)
2185 struct swdevt *sp, *tsp;
2190 * nblks is in DEV_BSIZE'd chunks, convert to PAGE_SIZE'd chunks.
2191 * First chop nblks off to page-align it, then convert.
2193 * sw->sw_nblks is in page-sized chunks now too.
2195 nblks &= ~(ctodb(1) - 1);
2196 nblks = dbtoc(nblks);
2199 * If we go beyond this, we get overflows in the radix
2202 mblocks = 0x40000000 / BLIST_META_RADIX;
2203 if (nblks > mblocks) {
2205 "WARNING: reducing swap size to maximum of %luMB per unit\n",
2206 mblocks / 1024 / 1024 * PAGE_SIZE);
2210 sp = malloc(sizeof *sp, M_VMPGDATA, M_WAITOK | M_ZERO);
2215 sp->sw_nblks = nblks;
2217 sp->sw_strategy = strategy;
2218 sp->sw_close = close;
2219 sp->sw_flags = flags;
2221 sp->sw_blist = blist_create(nblks, M_WAITOK);
2223 * Do not free the first two block in order to avoid overwriting
2224 * any bsd label at the front of the partition
2226 blist_free(sp->sw_blist, 2, nblks - 2);
2229 mtx_lock(&sw_dev_mtx);
2230 TAILQ_FOREACH(tsp, &swtailq, sw_list) {
2231 if (tsp->sw_end >= dvbase) {
2233 * We put one uncovered page between the devices
2234 * in order to definitively prevent any cross-device
2237 dvbase = tsp->sw_end + 1;
2240 sp->sw_first = dvbase;
2241 sp->sw_end = dvbase + nblks;
2242 TAILQ_INSERT_TAIL(&swtailq, sp, sw_list);
2244 swap_pager_avail += nblks - 2;
2245 swap_total += (vm_ooffset_t)nblks * PAGE_SIZE;
2246 swapon_check_swzone(swap_total / PAGE_SIZE);
2248 mtx_unlock(&sw_dev_mtx);
2252 * SYSCALL: swapoff(devname)
2254 * Disable swapping on the given device.
2256 * XXX: Badly designed system call: it should use a device index
2257 * rather than filename as specification. We keep sw_vp around
2258 * only to make this work.
2260 #ifndef _SYS_SYSPROTO_H_
2261 struct swapoff_args {
2271 sys_swapoff(struct thread *td, struct swapoff_args *uap)
2274 struct nameidata nd;
2278 error = priv_check(td, PRIV_SWAPOFF);
2283 while (swdev_syscall_active)
2284 tsleep(&swdev_syscall_active, PUSER - 1, "swpoff", 0);
2285 swdev_syscall_active = 1;
2287 NDINIT(&nd, LOOKUP, FOLLOW | AUDITVNODE1, UIO_USERSPACE, uap->name,
2292 NDFREE(&nd, NDF_ONLY_PNBUF);
2295 mtx_lock(&sw_dev_mtx);
2296 TAILQ_FOREACH(sp, &swtailq, sw_list) {
2297 if (sp->sw_vp == vp)
2300 mtx_unlock(&sw_dev_mtx);
2305 error = swapoff_one(sp, td->td_ucred);
2307 swdev_syscall_active = 0;
2308 wakeup_one(&swdev_syscall_active);
2314 swapoff_one(struct swdevt *sp, struct ucred *cred)
2321 mtx_assert(&Giant, MA_OWNED);
2323 (void) vn_lock(sp->sw_vp, LK_EXCLUSIVE | LK_RETRY);
2324 error = mac_system_check_swapoff(cred, sp->sw_vp);
2325 (void) VOP_UNLOCK(sp->sw_vp, 0);
2329 nblks = sp->sw_nblks;
2332 * We can turn off this swap device safely only if the
2333 * available virtual memory in the system will fit the amount
2334 * of data we will have to page back in, plus an epsilon so
2335 * the system doesn't become critically low on swap space.
2337 if (cnt.v_free_count + cnt.v_cache_count + swap_pager_avail <
2338 nblks + nswap_lowat) {
2343 * Prevent further allocations on this device.
2345 mtx_lock(&sw_dev_mtx);
2346 sp->sw_flags |= SW_CLOSING;
2347 swap_pager_avail -= blist_fill(sp->sw_blist, 0, nblks);
2348 swap_total -= (vm_ooffset_t)nblks * PAGE_SIZE;
2349 mtx_unlock(&sw_dev_mtx);
2352 * Page in the contents of the device and close it.
2354 swap_pager_swapoff(sp);
2356 sp->sw_close(curthread, sp);
2357 mtx_lock(&sw_dev_mtx);
2359 TAILQ_REMOVE(&swtailq, sp, sw_list);
2361 if (nswapdev == 0) {
2362 swap_pager_full = 2;
2363 swap_pager_almost_full = 1;
2367 mtx_unlock(&sw_dev_mtx);
2368 blist_destroy(sp->sw_blist);
2369 free(sp, M_VMPGDATA);
2376 struct swdevt *sp, *spt;
2377 const char *devname;
2381 while (swdev_syscall_active)
2382 tsleep(&swdev_syscall_active, PUSER - 1, "swpoff", 0);
2383 swdev_syscall_active = 1;
2385 mtx_lock(&sw_dev_mtx);
2386 TAILQ_FOREACH_SAFE(sp, &swtailq, sw_list, spt) {
2387 mtx_unlock(&sw_dev_mtx);
2388 if (vn_isdisk(sp->sw_vp, NULL))
2389 devname = devtoname(sp->sw_vp->v_rdev);
2392 error = swapoff_one(sp, thread0.td_ucred);
2394 printf("Cannot remove swap device %s (error=%d), "
2395 "skipping.\n", devname, error);
2396 } else if (bootverbose) {
2397 printf("Swap device %s removed.\n", devname);
2399 mtx_lock(&sw_dev_mtx);
2401 mtx_unlock(&sw_dev_mtx);
2403 swdev_syscall_active = 0;
2404 wakeup_one(&swdev_syscall_active);
2409 swap_pager_status(int *total, int *used)
2415 mtx_lock(&sw_dev_mtx);
2416 TAILQ_FOREACH(sp, &swtailq, sw_list) {
2417 *total += sp->sw_nblks;
2418 *used += sp->sw_used;
2420 mtx_unlock(&sw_dev_mtx);
2424 swap_dev_info(int name, struct xswdev *xs, char *devname, size_t len)
2427 const char *tmp_devname;
2432 mtx_lock(&sw_dev_mtx);
2433 TAILQ_FOREACH(sp, &swtailq, sw_list) {
2438 xs->xsw_version = XSWDEV_VERSION;
2439 xs->xsw_dev = sp->sw_dev;
2440 xs->xsw_flags = sp->sw_flags;
2441 xs->xsw_nblks = sp->sw_nblks;
2442 xs->xsw_used = sp->sw_used;
2443 if (devname != NULL) {
2444 if (vn_isdisk(sp->sw_vp, NULL))
2445 tmp_devname = devtoname(sp->sw_vp->v_rdev);
2447 tmp_devname = "[file]";
2448 strncpy(devname, tmp_devname, len);
2453 mtx_unlock(&sw_dev_mtx);
2458 sysctl_vm_swap_info(SYSCTL_HANDLER_ARGS)
2463 if (arg2 != 1) /* name length */
2465 error = swap_dev_info(*(int *)arg1, &xs, NULL, 0);
2468 error = SYSCTL_OUT(req, &xs, sizeof(xs));
2472 SYSCTL_INT(_vm, OID_AUTO, nswapdev, CTLFLAG_RD, &nswapdev, 0,
2473 "Number of swap devices");
2474 SYSCTL_NODE(_vm, OID_AUTO, swap_info, CTLFLAG_RD, sysctl_vm_swap_info,
2475 "Swap statistics by device");
2478 * vmspace_swap_count() - count the approximate swap usage in pages for a
2481 * The map must be locked.
2483 * Swap usage is determined by taking the proportional swap used by
2484 * VM objects backing the VM map. To make up for fractional losses,
2485 * if the VM object has any swap use at all the associated map entries
2486 * count for at least 1 swap page.
2489 vmspace_swap_count(struct vmspace *vmspace)
2496 map = &vmspace->vm_map;
2499 for (cur = map->header.next; cur != &map->header; cur = cur->next) {
2500 if ((cur->eflags & MAP_ENTRY_IS_SUB_MAP) == 0 &&
2501 (object = cur->object.vm_object) != NULL) {
2502 VM_OBJECT_WLOCK(object);
2503 if (object->type == OBJT_SWAP &&
2504 object->un_pager.swp.swp_bcount != 0) {
2505 n = (cur->end - cur->start) / PAGE_SIZE;
2506 count += object->un_pager.swp.swp_bcount *
2507 SWAP_META_PAGES * n / object->size + 1;
2509 VM_OBJECT_WUNLOCK(object);
2518 * Swapping onto disk devices.
2522 static g_orphan_t swapgeom_orphan;
2524 static struct g_class g_swap_class = {
2526 .version = G_VERSION,
2527 .orphan = swapgeom_orphan,
2530 DECLARE_GEOM_CLASS(g_swap_class, g_class);
2534 swapgeom_close_ev(void *arg, int flags)
2536 struct g_consumer *cp;
2539 g_access(cp, -1, -1, 0);
2541 g_destroy_consumer(cp);
2545 * Add a reference to the g_consumer for an inflight transaction.
2548 swapgeom_acquire(struct g_consumer *cp)
2551 mtx_assert(&sw_dev_mtx, MA_OWNED);
2556 * Remove a reference from the g_consumer. Post a close event if
2557 * all referneces go away.
2560 swapgeom_release(struct g_consumer *cp, struct swdevt *sp)
2563 mtx_assert(&sw_dev_mtx, MA_OWNED);
2565 if (cp->index == 0) {
2566 if (g_post_event(swapgeom_close_ev, cp, M_NOWAIT, NULL) == 0)
2572 swapgeom_done(struct bio *bp2)
2576 struct g_consumer *cp;
2578 bp = bp2->bio_caller2;
2580 bp->b_ioflags = bp2->bio_flags;
2582 bp->b_ioflags |= BIO_ERROR;
2583 bp->b_resid = bp->b_bcount - bp2->bio_completed;
2584 bp->b_error = bp2->bio_error;
2586 sp = bp2->bio_caller1;
2587 mtx_lock(&sw_dev_mtx);
2588 swapgeom_release(cp, sp);
2589 mtx_unlock(&sw_dev_mtx);
2594 swapgeom_strategy(struct buf *bp, struct swdevt *sp)
2597 struct g_consumer *cp;
2599 mtx_lock(&sw_dev_mtx);
2602 mtx_unlock(&sw_dev_mtx);
2603 bp->b_error = ENXIO;
2604 bp->b_ioflags |= BIO_ERROR;
2608 swapgeom_acquire(cp);
2609 mtx_unlock(&sw_dev_mtx);
2610 if (bp->b_iocmd == BIO_WRITE)
2613 bio = g_alloc_bio();
2615 mtx_lock(&sw_dev_mtx);
2616 swapgeom_release(cp, sp);
2617 mtx_unlock(&sw_dev_mtx);
2618 bp->b_error = ENOMEM;
2619 bp->b_ioflags |= BIO_ERROR;
2624 bio->bio_caller1 = sp;
2625 bio->bio_caller2 = bp;
2626 bio->bio_cmd = bp->b_iocmd;
2627 bio->bio_offset = (bp->b_blkno - sp->sw_first) * PAGE_SIZE;
2628 bio->bio_length = bp->b_bcount;
2629 bio->bio_done = swapgeom_done;
2630 if ((bp->b_flags & B_UNMAPPED) != 0) {
2631 bio->bio_ma = bp->b_pages;
2632 bio->bio_data = unmapped_buf;
2633 bio->bio_ma_offset = (vm_offset_t)bp->b_offset & PAGE_MASK;
2634 bio->bio_ma_n = bp->b_npages;
2635 bio->bio_flags |= BIO_UNMAPPED;
2637 bio->bio_data = bp->b_data;
2640 g_io_request(bio, cp);
2645 swapgeom_orphan(struct g_consumer *cp)
2650 mtx_lock(&sw_dev_mtx);
2651 TAILQ_FOREACH(sp, &swtailq, sw_list) {
2652 if (sp->sw_id == cp) {
2653 sp->sw_flags |= SW_CLOSING;
2658 * Drop reference we were created with. Do directly since we're in a
2659 * special context where we don't have to queue the call to
2660 * swapgeom_close_ev().
2663 destroy = ((sp != NULL) && (cp->index == 0));
2666 mtx_unlock(&sw_dev_mtx);
2668 swapgeom_close_ev(cp, 0);
2672 swapgeom_close(struct thread *td, struct swdevt *sw)
2674 struct g_consumer *cp;
2676 mtx_lock(&sw_dev_mtx);
2679 mtx_unlock(&sw_dev_mtx);
2680 /* XXX: direct call when Giant untangled */
2682 g_waitfor_event(swapgeom_close_ev, cp, M_WAITOK, NULL);
2693 swapongeom_ev(void *arg, int flags)
2696 struct g_provider *pp;
2697 struct g_consumer *cp;
2698 static struct g_geom *gp;
2705 pp = g_dev_getprovider(swh->dev);
2707 swh->error = ENODEV;
2710 mtx_lock(&sw_dev_mtx);
2711 TAILQ_FOREACH(sp, &swtailq, sw_list) {
2713 if (cp != NULL && cp->provider == pp) {
2714 mtx_unlock(&sw_dev_mtx);
2719 mtx_unlock(&sw_dev_mtx);
2721 gp = g_new_geomf(&g_swap_class, "swap");
2722 cp = g_new_consumer(gp);
2723 cp->index = 1; /* Number of active I/Os, plus one for being active. */
2724 cp->flags |= G_CF_DIRECT_SEND | G_CF_DIRECT_RECEIVE;
2727 * XXX: Everytime you think you can improve the margin for
2728 * footshooting, somebody depends on the ability to do so:
2729 * savecore(8) wants to write to our swapdev so we cannot
2730 * set an exclusive count :-(
2732 error = g_access(cp, 1, 1, 0);
2735 g_destroy_consumer(cp);
2739 nblks = pp->mediasize / DEV_BSIZE;
2740 swaponsomething(swh->vp, cp, nblks, swapgeom_strategy,
2741 swapgeom_close, dev2udev(swh->dev),
2742 (pp->flags & G_PF_ACCEPT_UNMAPPED) != 0 ? SW_UNMAPPED : 0);
2747 swapongeom(struct thread *td, struct vnode *vp)
2752 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
2754 swh.dev = vp->v_rdev;
2757 /* XXX: direct call when Giant untangled */
2758 error = g_waitfor_event(swapongeom_ev, &swh, M_WAITOK, NULL);
2768 * This is used mainly for network filesystem (read: probably only tested
2769 * with NFS) swapfiles.
2774 swapdev_strategy(struct buf *bp, struct swdevt *sp)
2778 bp->b_blkno = ctodb(bp->b_blkno - sp->sw_first);
2782 if (bp->b_iocmd == BIO_WRITE) {
2784 bufobj_wdrop(bp->b_bufobj);
2785 bufobj_wref(&vp2->v_bufobj);
2787 if (bp->b_bufobj != &vp2->v_bufobj)
2788 bp->b_bufobj = &vp2->v_bufobj;
2790 bp->b_iooffset = dbtob(bp->b_blkno);
2796 swapdev_close(struct thread *td, struct swdevt *sp)
2799 VOP_CLOSE(sp->sw_vp, FREAD | FWRITE, td->td_ucred, td);
2805 swaponvp(struct thread *td, struct vnode *vp, u_long nblks)
2812 mtx_lock(&sw_dev_mtx);
2813 TAILQ_FOREACH(sp, &swtailq, sw_list) {
2814 if (sp->sw_id == vp) {
2815 mtx_unlock(&sw_dev_mtx);
2819 mtx_unlock(&sw_dev_mtx);
2821 (void) vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
2823 error = mac_system_check_swapon(td->td_ucred, vp);
2826 error = VOP_OPEN(vp, FREAD | FWRITE, td->td_ucred, td, NULL);
2827 (void) VOP_UNLOCK(vp, 0);
2831 swaponsomething(vp, vp, nblks, swapdev_strategy, swapdev_close,