2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
4 * Copyright (c) 2002-2006 Rice University
5 * Copyright (c) 2007-2011 Alan L. Cox <alc@cs.rice.edu>
8 * This software was developed for the FreeBSD Project by Alan L. Cox,
9 * Olivier Crameri, Peter Druschel, Sitaram Iyer, and Juan Navarro.
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
14 * 1. Redistributions of source code must retain the above copyright
15 * notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in the
18 * documentation and/or other materials provided with the distribution.
20 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
22 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
23 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
24 * HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
25 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
26 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
27 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
28 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY
30 * WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
31 * POSSIBILITY OF SUCH DAMAGE.
35 * Superpage reservation management module
37 * Any external functions defined by this module are only to be used by the
38 * virtual memory system.
41 #include <sys/cdefs.h>
42 __FBSDID("$FreeBSD$");
46 #include <sys/param.h>
47 #include <sys/kernel.h>
49 #include <sys/malloc.h>
50 #include <sys/mutex.h>
51 #include <sys/queue.h>
52 #include <sys/rwlock.h>
54 #include <sys/sysctl.h>
55 #include <sys/systm.h>
56 #include <sys/counter.h>
58 #include <sys/vmmeter.h>
62 #include <vm/vm_param.h>
63 #include <vm/vm_object.h>
64 #include <vm/vm_page.h>
65 #include <vm/vm_pageout.h>
66 #include <vm/vm_phys.h>
67 #include <vm/vm_pagequeue.h>
68 #include <vm/vm_radix.h>
69 #include <vm/vm_reserv.h>
72 * The reservation system supports the speculative allocation of large physical
73 * pages ("superpages"). Speculative allocation enables the fully automatic
74 * utilization of superpages by the virtual memory system. In other words, no
75 * programmatic directives are required to use superpages.
78 #if VM_NRESERVLEVEL > 0
80 #ifndef VM_LEVEL_0_ORDER_MAX
81 #define VM_LEVEL_0_ORDER_MAX VM_LEVEL_0_ORDER
85 * The number of small pages that are contained in a level 0 reservation
87 #define VM_LEVEL_0_NPAGES (1 << VM_LEVEL_0_ORDER)
88 #define VM_LEVEL_0_NPAGES_MAX (1 << VM_LEVEL_0_ORDER_MAX)
91 * The number of bits by which a physical address is shifted to obtain the
94 #define VM_LEVEL_0_SHIFT (VM_LEVEL_0_ORDER + PAGE_SHIFT)
97 * The size of a level 0 reservation in bytes
99 #define VM_LEVEL_0_SIZE (1 << VM_LEVEL_0_SHIFT)
102 * Computes the index of the small page underlying the given (object, pindex)
103 * within the reservation's array of small pages.
105 #define VM_RESERV_INDEX(object, pindex) \
106 (((object)->pg_color + (pindex)) & (VM_LEVEL_0_NPAGES - 1))
109 * The size of a population map entry
111 typedef u_long popmap_t;
114 * The number of bits in a population map entry
116 #define NBPOPMAP (NBBY * sizeof(popmap_t))
119 * The number of population map entries in a reservation
121 #define NPOPMAP howmany(VM_LEVEL_0_NPAGES, NBPOPMAP)
122 #define NPOPMAP_MAX howmany(VM_LEVEL_0_NPAGES_MAX, NBPOPMAP)
125 * Number of elapsed ticks before we update the LRU queue position. Used
126 * to reduce contention and churn on the list.
128 #define PARTPOPSLOP 1
131 * Clear a bit in the population map.
134 popmap_clear(popmap_t popmap[], int i)
137 popmap[i / NBPOPMAP] &= ~(1UL << (i % NBPOPMAP));
141 * Set a bit in the population map.
144 popmap_set(popmap_t popmap[], int i)
147 popmap[i / NBPOPMAP] |= 1UL << (i % NBPOPMAP);
151 * Is a bit in the population map clear?
153 static __inline boolean_t
154 popmap_is_clear(popmap_t popmap[], int i)
157 return ((popmap[i / NBPOPMAP] & (1UL << (i % NBPOPMAP))) == 0);
161 * Is a bit in the population map set?
163 static __inline boolean_t
164 popmap_is_set(popmap_t popmap[], int i)
167 return ((popmap[i / NBPOPMAP] & (1UL << (i % NBPOPMAP))) != 0);
171 * The reservation structure
173 * A reservation structure is constructed whenever a large physical page is
174 * speculatively allocated to an object. The reservation provides the small
175 * physical pages for the range [pindex, pindex + VM_LEVEL_0_NPAGES) of offsets
176 * within that object. The reservation's "popcnt" tracks the number of these
177 * small physical pages that are in use at any given time. When and if the
178 * reservation is not fully utilized, it appears in the queue of partially
179 * populated reservations. The reservation always appears on the containing
180 * object's list of reservations.
182 * A partially populated reservation can be broken and reclaimed at any time.
184 * c - constant after boot
185 * d - vm_reserv_domain_lock
186 * o - vm_reserv_object_lock
188 * s - vm_reserv_domain_scan_lock
191 struct mtx lock; /* reservation lock. */
192 TAILQ_ENTRY(vm_reserv) partpopq; /* (d, r) per-domain queue. */
193 LIST_ENTRY(vm_reserv) objq; /* (o, r) object queue */
194 vm_object_t object; /* (o, r) containing object */
195 vm_pindex_t pindex; /* (o, r) offset in object */
196 vm_page_t pages; /* (c) first page */
197 uint16_t popcnt; /* (r) # of pages in use */
198 uint8_t domain; /* (c) NUMA domain. */
199 char inpartpopq; /* (d, r) */
200 int lasttick; /* (r) last pop update tick. */
201 popmap_t popmap[NPOPMAP_MAX]; /* (r) bit vector, used pages */
204 TAILQ_HEAD(vm_reserv_queue, vm_reserv);
206 #define vm_reserv_lockptr(rv) (&(rv)->lock)
207 #define vm_reserv_assert_locked(rv) \
208 mtx_assert(vm_reserv_lockptr(rv), MA_OWNED)
209 #define vm_reserv_lock(rv) mtx_lock(vm_reserv_lockptr(rv))
210 #define vm_reserv_trylock(rv) mtx_trylock(vm_reserv_lockptr(rv))
211 #define vm_reserv_unlock(rv) mtx_unlock(vm_reserv_lockptr(rv))
214 * The reservation array
216 * This array is analoguous in function to vm_page_array. It differs in the
217 * respect that it may contain a greater number of useful reservation
218 * structures than there are (physical) superpages. These "invalid"
219 * reservation structures exist to trade-off space for time in the
220 * implementation of vm_reserv_from_page(). Invalid reservation structures are
221 * distinguishable from "valid" reservation structures by inspecting the
222 * reservation's "pages" field. Invalid reservation structures have a NULL
225 * vm_reserv_from_page() maps a small (physical) page to an element of this
226 * array by computing a physical reservation number from the page's physical
227 * address. The physical reservation number is used as the array index.
229 * An "active" reservation is a valid reservation structure that has a non-NULL
230 * "object" field and a non-zero "popcnt" field. In other words, every active
231 * reservation belongs to a particular object. Moreover, every active
232 * reservation has an entry in the containing object's list of reservations.
234 static vm_reserv_t vm_reserv_array;
237 * The per-domain partially populated reservation queues
239 * These queues enable the fast recovery of an unused free small page from a
240 * partially populated reservation. The reservation at the head of a queue
241 * is the least recently changed, partially populated reservation.
243 * Access to this queue is synchronized by the per-domain reservation lock.
244 * Threads reclaiming free pages from the queue must hold the per-domain scan
247 struct vm_reserv_domain {
249 struct vm_reserv_queue partpop; /* (d) */
250 struct vm_reserv marker; /* (d, s) scan marker/lock */
251 } __aligned(CACHE_LINE_SIZE);
253 static struct vm_reserv_domain vm_rvd[MAXMEMDOM];
255 #define vm_reserv_domain_lockptr(d) (&vm_rvd[(d)].lock)
256 #define vm_reserv_domain_assert_locked(d) \
257 mtx_assert(vm_reserv_domain_lockptr(d), MA_OWNED)
258 #define vm_reserv_domain_lock(d) mtx_lock(vm_reserv_domain_lockptr(d))
259 #define vm_reserv_domain_unlock(d) mtx_unlock(vm_reserv_domain_lockptr(d))
261 #define vm_reserv_domain_scan_lock(d) mtx_lock(&vm_rvd[(d)].marker.lock)
262 #define vm_reserv_domain_scan_unlock(d) mtx_unlock(&vm_rvd[(d)].marker.lock)
264 static SYSCTL_NODE(_vm, OID_AUTO, reserv, CTLFLAG_RD | CTLFLAG_MPSAFE, 0,
267 static COUNTER_U64_DEFINE_EARLY(vm_reserv_broken);
268 SYSCTL_COUNTER_U64(_vm_reserv, OID_AUTO, broken, CTLFLAG_RD,
269 &vm_reserv_broken, "Cumulative number of broken reservations");
271 static COUNTER_U64_DEFINE_EARLY(vm_reserv_freed);
272 SYSCTL_COUNTER_U64(_vm_reserv, OID_AUTO, freed, CTLFLAG_RD,
273 &vm_reserv_freed, "Cumulative number of freed reservations");
275 static int sysctl_vm_reserv_fullpop(SYSCTL_HANDLER_ARGS);
277 SYSCTL_PROC(_vm_reserv, OID_AUTO, fullpop, CTLTYPE_INT | CTLFLAG_MPSAFE | CTLFLAG_RD,
278 NULL, 0, sysctl_vm_reserv_fullpop, "I", "Current number of full reservations");
280 static int sysctl_vm_reserv_partpopq(SYSCTL_HANDLER_ARGS);
282 SYSCTL_OID(_vm_reserv, OID_AUTO, partpopq,
283 CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_NEEDGIANT, NULL, 0,
284 sysctl_vm_reserv_partpopq, "A",
285 "Partially populated reservation queues");
287 static COUNTER_U64_DEFINE_EARLY(vm_reserv_reclaimed);
288 SYSCTL_COUNTER_U64(_vm_reserv, OID_AUTO, reclaimed, CTLFLAG_RD,
289 &vm_reserv_reclaimed, "Cumulative number of reclaimed reservations");
292 * The object lock pool is used to synchronize the rvq. We can not use a
293 * pool mutex because it is required before malloc works.
295 * The "hash" function could be made faster without divide and modulo.
297 #define VM_RESERV_OBJ_LOCK_COUNT MAXCPU
299 struct mtx_padalign vm_reserv_object_mtx[VM_RESERV_OBJ_LOCK_COUNT];
301 #define vm_reserv_object_lock_idx(object) \
302 (((uintptr_t)object / sizeof(*object)) % VM_RESERV_OBJ_LOCK_COUNT)
303 #define vm_reserv_object_lock_ptr(object) \
304 &vm_reserv_object_mtx[vm_reserv_object_lock_idx((object))]
305 #define vm_reserv_object_lock(object) \
306 mtx_lock(vm_reserv_object_lock_ptr((object)))
307 #define vm_reserv_object_unlock(object) \
308 mtx_unlock(vm_reserv_object_lock_ptr((object)))
310 static void vm_reserv_break(vm_reserv_t rv);
311 static void vm_reserv_depopulate(vm_reserv_t rv, int index);
312 static vm_reserv_t vm_reserv_from_page(vm_page_t m);
313 static boolean_t vm_reserv_has_pindex(vm_reserv_t rv,
315 static void vm_reserv_populate(vm_reserv_t rv, int index);
316 static void vm_reserv_reclaim(vm_reserv_t rv);
319 * Returns the current number of full reservations.
321 * Since the number of full reservations is computed without acquiring any
322 * locks, the returned value is inexact.
325 sysctl_vm_reserv_fullpop(SYSCTL_HANDLER_ARGS)
328 struct vm_phys_seg *seg;
333 for (segind = 0; segind < vm_phys_nsegs; segind++) {
334 seg = &vm_phys_segs[segind];
335 paddr = roundup2(seg->start, VM_LEVEL_0_SIZE);
336 while (paddr + VM_LEVEL_0_SIZE > paddr && paddr +
337 VM_LEVEL_0_SIZE <= seg->end) {
338 rv = &vm_reserv_array[paddr >> VM_LEVEL_0_SHIFT];
339 fullpop += rv->popcnt == VM_LEVEL_0_NPAGES;
340 paddr += VM_LEVEL_0_SIZE;
343 return (sysctl_handle_int(oidp, &fullpop, 0, req));
347 * Describes the current state of the partially populated reservation queue.
350 sysctl_vm_reserv_partpopq(SYSCTL_HANDLER_ARGS)
354 int counter, error, domain, level, unused_pages;
356 error = sysctl_wire_old_buffer(req, 0);
359 sbuf_new_for_sysctl(&sbuf, NULL, 128, req);
360 sbuf_printf(&sbuf, "\nDOMAIN LEVEL SIZE NUMBER\n\n");
361 for (domain = 0; domain < vm_ndomains; domain++) {
362 for (level = -1; level <= VM_NRESERVLEVEL - 2; level++) {
365 vm_reserv_domain_lock(domain);
366 TAILQ_FOREACH(rv, &vm_rvd[domain].partpop, partpopq) {
367 if (rv == &vm_rvd[domain].marker)
370 unused_pages += VM_LEVEL_0_NPAGES - rv->popcnt;
372 vm_reserv_domain_unlock(domain);
373 sbuf_printf(&sbuf, "%6d, %7d, %6dK, %6d\n",
375 unused_pages * ((int)PAGE_SIZE / 1024), counter);
378 error = sbuf_finish(&sbuf);
384 * Remove a reservation from the object's objq.
387 vm_reserv_remove(vm_reserv_t rv)
391 vm_reserv_assert_locked(rv);
392 CTR5(KTR_VM, "%s: rv %p object %p popcnt %d inpartpop %d",
393 __FUNCTION__, rv, rv->object, rv->popcnt, rv->inpartpopq);
394 KASSERT(rv->object != NULL,
395 ("vm_reserv_remove: reserv %p is free", rv));
396 KASSERT(!rv->inpartpopq,
397 ("vm_reserv_remove: reserv %p's inpartpopq is TRUE", rv));
399 vm_reserv_object_lock(object);
400 LIST_REMOVE(rv, objq);
402 vm_reserv_object_unlock(object);
406 * Insert a new reservation into the object's objq.
409 vm_reserv_insert(vm_reserv_t rv, vm_object_t object, vm_pindex_t pindex)
413 vm_reserv_assert_locked(rv);
415 "%s: rv %p(%p) object %p new %p popcnt %d",
416 __FUNCTION__, rv, rv->pages, rv->object, object,
418 KASSERT(rv->object == NULL,
419 ("vm_reserv_insert: reserv %p isn't free", rv));
420 KASSERT(rv->popcnt == 0,
421 ("vm_reserv_insert: reserv %p's popcnt is corrupted", rv));
422 KASSERT(!rv->inpartpopq,
423 ("vm_reserv_insert: reserv %p's inpartpopq is TRUE", rv));
424 for (i = 0; i < NPOPMAP; i++)
425 KASSERT(rv->popmap[i] == 0,
426 ("vm_reserv_insert: reserv %p's popmap is corrupted", rv));
427 vm_reserv_object_lock(object);
430 rv->lasttick = ticks;
431 LIST_INSERT_HEAD(&object->rvq, rv, objq);
432 vm_reserv_object_unlock(object);
436 * Reduces the given reservation's population count. If the population count
437 * becomes zero, the reservation is destroyed. Additionally, moves the
438 * reservation to the tail of the partially populated reservation queue if the
439 * population count is non-zero.
442 vm_reserv_depopulate(vm_reserv_t rv, int index)
444 struct vm_domain *vmd;
446 vm_reserv_assert_locked(rv);
447 CTR5(KTR_VM, "%s: rv %p object %p popcnt %d inpartpop %d",
448 __FUNCTION__, rv, rv->object, rv->popcnt, rv->inpartpopq);
449 KASSERT(rv->object != NULL,
450 ("vm_reserv_depopulate: reserv %p is free", rv));
451 KASSERT(popmap_is_set(rv->popmap, index),
452 ("vm_reserv_depopulate: reserv %p's popmap[%d] is clear", rv,
454 KASSERT(rv->popcnt > 0,
455 ("vm_reserv_depopulate: reserv %p's popcnt is corrupted", rv));
456 KASSERT(rv->domain < vm_ndomains,
457 ("vm_reserv_depopulate: reserv %p's domain is corrupted %d",
459 if (rv->popcnt == VM_LEVEL_0_NPAGES) {
460 KASSERT(rv->pages->psind == 1,
461 ("vm_reserv_depopulate: reserv %p is already demoted",
463 rv->pages->psind = 0;
465 popmap_clear(rv->popmap, index);
467 if ((unsigned)(ticks - rv->lasttick) >= PARTPOPSLOP ||
469 vm_reserv_domain_lock(rv->domain);
470 if (rv->inpartpopq) {
471 TAILQ_REMOVE(&vm_rvd[rv->domain].partpop, rv, partpopq);
472 rv->inpartpopq = FALSE;
474 if (rv->popcnt != 0) {
475 rv->inpartpopq = TRUE;
476 TAILQ_INSERT_TAIL(&vm_rvd[rv->domain].partpop, rv,
479 vm_reserv_domain_unlock(rv->domain);
480 rv->lasttick = ticks;
482 vmd = VM_DOMAIN(rv->domain);
483 if (rv->popcnt == 0) {
484 vm_reserv_remove(rv);
485 vm_domain_free_lock(vmd);
486 vm_phys_free_pages(rv->pages, VM_LEVEL_0_ORDER);
487 vm_domain_free_unlock(vmd);
488 counter_u64_add(vm_reserv_freed, 1);
490 vm_domain_freecnt_inc(vmd, 1);
494 * Returns the reservation to which the given page might belong.
496 static __inline vm_reserv_t
497 vm_reserv_from_page(vm_page_t m)
500 return (&vm_reserv_array[VM_PAGE_TO_PHYS(m) >> VM_LEVEL_0_SHIFT]);
504 * Returns an existing reservation or NULL and initialized successor pointer.
507 vm_reserv_from_object(vm_object_t object, vm_pindex_t pindex,
508 vm_page_t mpred, vm_page_t *msuccp)
515 KASSERT(mpred->object == object,
516 ("vm_reserv_from_object: object doesn't contain mpred"));
517 KASSERT(mpred->pindex < pindex,
518 ("vm_reserv_from_object: mpred doesn't precede pindex"));
519 rv = vm_reserv_from_page(mpred);
520 if (rv->object == object && vm_reserv_has_pindex(rv, pindex))
522 msucc = TAILQ_NEXT(mpred, listq);
524 msucc = TAILQ_FIRST(&object->memq);
526 KASSERT(msucc->pindex > pindex,
527 ("vm_reserv_from_object: msucc doesn't succeed pindex"));
528 rv = vm_reserv_from_page(msucc);
529 if (rv->object == object && vm_reserv_has_pindex(rv, pindex))
541 * Returns TRUE if the given reservation contains the given page index and
544 static __inline boolean_t
545 vm_reserv_has_pindex(vm_reserv_t rv, vm_pindex_t pindex)
548 return (((pindex - rv->pindex) & ~(VM_LEVEL_0_NPAGES - 1)) == 0);
552 * Increases the given reservation's population count. Moves the reservation
553 * to the tail of the partially populated reservation queue.
556 vm_reserv_populate(vm_reserv_t rv, int index)
559 vm_reserv_assert_locked(rv);
560 CTR5(KTR_VM, "%s: rv %p object %p popcnt %d inpartpop %d",
561 __FUNCTION__, rv, rv->object, rv->popcnt, rv->inpartpopq);
562 KASSERT(rv->object != NULL,
563 ("vm_reserv_populate: reserv %p is free", rv));
564 KASSERT(popmap_is_clear(rv->popmap, index),
565 ("vm_reserv_populate: reserv %p's popmap[%d] is set", rv,
567 KASSERT(rv->popcnt < VM_LEVEL_0_NPAGES,
568 ("vm_reserv_populate: reserv %p is already full", rv));
569 KASSERT(rv->pages->psind == 0,
570 ("vm_reserv_populate: reserv %p is already promoted", rv));
571 KASSERT(rv->domain < vm_ndomains,
572 ("vm_reserv_populate: reserv %p's domain is corrupted %d",
574 popmap_set(rv->popmap, index);
576 if ((unsigned)(ticks - rv->lasttick) < PARTPOPSLOP &&
577 rv->inpartpopq && rv->popcnt != VM_LEVEL_0_NPAGES)
579 rv->lasttick = ticks;
580 vm_reserv_domain_lock(rv->domain);
581 if (rv->inpartpopq) {
582 TAILQ_REMOVE(&vm_rvd[rv->domain].partpop, rv, partpopq);
583 rv->inpartpopq = FALSE;
585 if (rv->popcnt < VM_LEVEL_0_NPAGES) {
586 rv->inpartpopq = TRUE;
587 TAILQ_INSERT_TAIL(&vm_rvd[rv->domain].partpop, rv, partpopq);
589 KASSERT(rv->pages->psind == 0,
590 ("vm_reserv_populate: reserv %p is already promoted",
592 rv->pages->psind = 1;
594 vm_reserv_domain_unlock(rv->domain);
598 * Allocates a contiguous set of physical pages of the given size "npages"
599 * from existing or newly created reservations. All of the physical pages
600 * must be at or above the given physical address "low" and below the given
601 * physical address "high". The given value "alignment" determines the
602 * alignment of the first physical page in the set. If the given value
603 * "boundary" is non-zero, then the set of physical pages cannot cross any
604 * physical address boundary that is a multiple of that value. Both
605 * "alignment" and "boundary" must be a power of two.
607 * The page "mpred" must immediately precede the offset "pindex" within the
610 * The object must be locked.
613 vm_reserv_alloc_contig(vm_object_t object, vm_pindex_t pindex, int domain,
614 int req, vm_page_t mpred, u_long npages, vm_paddr_t low, vm_paddr_t high,
615 u_long alignment, vm_paddr_t boundary)
617 struct vm_domain *vmd;
619 vm_page_t m, m_ret, msucc;
620 vm_pindex_t first, leftcap, rightcap;
622 u_long allocpages, maxpages, minpages;
625 VM_OBJECT_ASSERT_WLOCKED(object);
626 KASSERT(npages != 0, ("vm_reserv_alloc_contig: npages is 0"));
629 * Is a reservation fundamentally impossible?
631 if (pindex < VM_RESERV_INDEX(object, pindex) ||
632 pindex + npages > object->size)
636 * All reservations of a particular size have the same alignment.
637 * Assuming that the first page is allocated from a reservation, the
638 * least significant bits of its physical address can be determined
639 * from its offset from the beginning of the reservation and the size
640 * of the reservation.
642 * Could the specified index within a reservation of the smallest
643 * possible size satisfy the alignment and boundary requirements?
645 pa = VM_RESERV_INDEX(object, pindex) << PAGE_SHIFT;
646 if ((pa & (alignment - 1)) != 0)
648 size = npages << PAGE_SHIFT;
649 if (((pa ^ (pa + size - 1)) & ~(boundary - 1)) != 0)
653 * Look for an existing reservation.
655 rv = vm_reserv_from_object(object, pindex, mpred, &msucc);
657 KASSERT(object != kernel_object || rv->domain == domain,
658 ("vm_reserv_alloc_contig: domain mismatch"));
659 index = VM_RESERV_INDEX(object, pindex);
660 /* Does the allocation fit within the reservation? */
661 if (index + npages > VM_LEVEL_0_NPAGES)
664 vmd = VM_DOMAIN(domain);
666 /* Handle reclaim race. */
667 if (rv->object != object)
669 m = &rv->pages[index];
670 pa = VM_PAGE_TO_PHYS(m);
671 if (pa < low || pa + size > high ||
672 (pa & (alignment - 1)) != 0 ||
673 ((pa ^ (pa + size - 1)) & ~(boundary - 1)) != 0)
675 /* Handle vm_page_rename(m, new_object, ...). */
676 for (i = 0; i < npages; i++)
677 if (popmap_is_set(rv->popmap, index + i))
679 if (!vm_domain_allocate(vmd, req, npages))
681 for (i = 0; i < npages; i++)
682 vm_reserv_populate(rv, index + i);
683 vm_reserv_unlock(rv);
686 vm_reserv_unlock(rv);
691 * Could at least one reservation fit between the first index to the
692 * left that can be used ("leftcap") and the first index to the right
693 * that cannot be used ("rightcap")?
695 * We must synchronize with the reserv object lock to protect the
696 * pindex/object of the resulting reservations against rename while
699 first = pindex - VM_RESERV_INDEX(object, pindex);
700 minpages = VM_RESERV_INDEX(object, pindex) + npages;
701 maxpages = roundup2(minpages, VM_LEVEL_0_NPAGES);
702 allocpages = maxpages;
703 vm_reserv_object_lock(object);
705 if ((rv = vm_reserv_from_page(mpred))->object != object)
706 leftcap = mpred->pindex + 1;
708 leftcap = rv->pindex + VM_LEVEL_0_NPAGES;
709 if (leftcap > first) {
710 vm_reserv_object_unlock(object);
715 if ((rv = vm_reserv_from_page(msucc))->object != object)
716 rightcap = msucc->pindex;
718 rightcap = rv->pindex;
719 if (first + maxpages > rightcap) {
720 if (maxpages == VM_LEVEL_0_NPAGES) {
721 vm_reserv_object_unlock(object);
726 * At least one reservation will fit between "leftcap"
727 * and "rightcap". However, a reservation for the
728 * last of the requested pages will not fit. Reduce
729 * the size of the upcoming allocation accordingly.
731 allocpages = minpages;
734 vm_reserv_object_unlock(object);
737 * Would the last new reservation extend past the end of the object?
739 * If the object is unlikely to grow don't allocate a reservation for
742 if ((object->flags & OBJ_ANON) == 0 &&
743 first + maxpages > object->size) {
744 if (maxpages == VM_LEVEL_0_NPAGES)
746 allocpages = minpages;
750 * Allocate the physical pages. The alignment and boundary specified
751 * for this allocation may be different from the alignment and
752 * boundary specified for the requested pages. For instance, the
753 * specified index may not be the first page within the first new
757 vmd = VM_DOMAIN(domain);
758 if (vm_domain_allocate(vmd, req, npages)) {
759 vm_domain_free_lock(vmd);
760 m = vm_phys_alloc_contig(domain, allocpages, low, high,
761 ulmax(alignment, VM_LEVEL_0_SIZE),
762 boundary > VM_LEVEL_0_SIZE ? boundary : 0);
763 vm_domain_free_unlock(vmd);
765 vm_domain_freecnt_inc(vmd, npages);
770 KASSERT(vm_phys_domain(m) == domain,
771 ("vm_reserv_alloc_contig: Page domain does not match requested."));
774 * The allocated physical pages always begin at a reservation
775 * boundary, but they do not always end at a reservation boundary.
776 * Initialize every reservation that is completely covered by the
777 * allocated physical pages.
780 index = VM_RESERV_INDEX(object, pindex);
782 rv = vm_reserv_from_page(m);
783 KASSERT(rv->pages == m,
784 ("vm_reserv_alloc_contig: reserv %p's pages is corrupted",
787 vm_reserv_insert(rv, object, first);
788 n = ulmin(VM_LEVEL_0_NPAGES - index, npages);
789 for (i = 0; i < n; i++)
790 vm_reserv_populate(rv, index + i);
793 m_ret = &rv->pages[index];
796 vm_reserv_unlock(rv);
797 m += VM_LEVEL_0_NPAGES;
798 first += VM_LEVEL_0_NPAGES;
799 allocpages -= VM_LEVEL_0_NPAGES;
800 } while (allocpages >= VM_LEVEL_0_NPAGES);
805 * Allocate a physical page from an existing or newly created reservation.
807 * The page "mpred" must immediately precede the offset "pindex" within the
810 * The object must be locked.
813 vm_reserv_alloc_page(vm_object_t object, vm_pindex_t pindex, int domain,
814 int req, vm_page_t mpred)
816 struct vm_domain *vmd;
818 vm_pindex_t first, leftcap, rightcap;
822 VM_OBJECT_ASSERT_WLOCKED(object);
825 * Is a reservation fundamentally impossible?
827 if (pindex < VM_RESERV_INDEX(object, pindex) ||
828 pindex >= object->size)
832 * Look for an existing reservation.
834 rv = vm_reserv_from_object(object, pindex, mpred, &msucc);
836 KASSERT(object != kernel_object || rv->domain == domain,
837 ("vm_reserv_alloc_page: domain mismatch"));
839 vmd = VM_DOMAIN(domain);
840 index = VM_RESERV_INDEX(object, pindex);
841 m = &rv->pages[index];
843 /* Handle reclaim race. */
844 if (rv->object != object ||
845 /* Handle vm_page_rename(m, new_object, ...). */
846 popmap_is_set(rv->popmap, index)) {
850 if (vm_domain_allocate(vmd, req, 1) == 0)
853 vm_reserv_populate(rv, index);
855 vm_reserv_unlock(rv);
860 * Could a reservation fit between the first index to the left that
861 * can be used and the first index to the right that cannot be used?
863 * We must synchronize with the reserv object lock to protect the
864 * pindex/object of the resulting reservations against rename while
867 first = pindex - VM_RESERV_INDEX(object, pindex);
868 vm_reserv_object_lock(object);
870 if ((rv = vm_reserv_from_page(mpred))->object != object)
871 leftcap = mpred->pindex + 1;
873 leftcap = rv->pindex + VM_LEVEL_0_NPAGES;
874 if (leftcap > first) {
875 vm_reserv_object_unlock(object);
880 if ((rv = vm_reserv_from_page(msucc))->object != object)
881 rightcap = msucc->pindex;
883 rightcap = rv->pindex;
884 if (first + VM_LEVEL_0_NPAGES > rightcap) {
885 vm_reserv_object_unlock(object);
889 vm_reserv_object_unlock(object);
892 * Would the last new reservation extend past the end of the object?
894 * If the object is unlikely to grow don't allocate a reservation for
897 if ((object->flags & OBJ_ANON) == 0 &&
898 first + VM_LEVEL_0_NPAGES > object->size)
902 * Allocate and populate the new reservation.
905 vmd = VM_DOMAIN(domain);
906 if (vm_domain_allocate(vmd, req, 1)) {
907 vm_domain_free_lock(vmd);
908 m = vm_phys_alloc_pages(domain, VM_FREEPOOL_DEFAULT,
910 vm_domain_free_unlock(vmd);
912 vm_domain_freecnt_inc(vmd, 1);
917 rv = vm_reserv_from_page(m);
919 KASSERT(rv->pages == m,
920 ("vm_reserv_alloc_page: reserv %p's pages is corrupted", rv));
921 vm_reserv_insert(rv, object, first);
922 index = VM_RESERV_INDEX(object, pindex);
923 vm_reserv_populate(rv, index);
924 vm_reserv_unlock(rv);
926 return (&rv->pages[index]);
930 * Breaks the given reservation. All free pages in the reservation
931 * are returned to the physical memory allocator. The reservation's
932 * population count and map are reset to their initial state.
934 * The given reservation must not be in the partially populated reservation
938 vm_reserv_break(vm_reserv_t rv)
941 int bitpos, hi, i, lo;
943 vm_reserv_assert_locked(rv);
944 CTR5(KTR_VM, "%s: rv %p object %p popcnt %d inpartpop %d",
945 __FUNCTION__, rv, rv->object, rv->popcnt, rv->inpartpopq);
946 vm_reserv_remove(rv);
947 rv->pages->psind = 0;
949 for (i = 0; i <= NPOPMAP; i++) {
951 * "changes" is a bitmask that marks where a new sequence of
952 * 0s or 1s begins in popmap[i], with last bit in popmap[i-1]
953 * considered to be 1 if and only if lo == hi. The bits of
954 * popmap[-1] and popmap[NPOPMAP] are considered all 1s.
959 changes = rv->popmap[i];
960 changes ^= (changes << 1) | (lo == hi);
963 while (changes != 0) {
965 * If the next change marked begins a run of 0s, set
966 * lo to mark that position. Otherwise set hi and
967 * free pages from lo up to hi.
969 bitpos = ffsl(changes) - 1;
970 changes ^= 1UL << bitpos;
972 lo = NBPOPMAP * i + bitpos;
974 hi = NBPOPMAP * i + bitpos;
975 vm_domain_free_lock(VM_DOMAIN(rv->domain));
976 vm_phys_enqueue_contig(&rv->pages[lo], hi - lo);
977 vm_domain_free_unlock(VM_DOMAIN(rv->domain));
983 counter_u64_add(vm_reserv_broken, 1);
987 * Breaks all reservations belonging to the given object.
990 vm_reserv_break_all(vm_object_t object)
995 * This access of object->rvq is unsynchronized so that the
996 * object rvq lock can nest after the domain_free lock. We
997 * must check for races in the results. However, the object
998 * lock prevents new additions, so we are guaranteed that when
999 * it returns NULL the object is properly empty.
1001 while ((rv = LIST_FIRST(&object->rvq)) != NULL) {
1004 if (rv->object != object) {
1005 vm_reserv_unlock(rv);
1008 vm_reserv_domain_lock(rv->domain);
1009 if (rv->inpartpopq) {
1010 TAILQ_REMOVE(&vm_rvd[rv->domain].partpop, rv, partpopq);
1011 rv->inpartpopq = FALSE;
1013 vm_reserv_domain_unlock(rv->domain);
1014 vm_reserv_break(rv);
1015 vm_reserv_unlock(rv);
1020 * Frees the given page if it belongs to a reservation. Returns TRUE if the
1021 * page is freed and FALSE otherwise.
1024 vm_reserv_free_page(vm_page_t m)
1029 rv = vm_reserv_from_page(m);
1030 if (rv->object == NULL)
1033 /* Re-validate after lock. */
1034 if (rv->object != NULL) {
1035 vm_reserv_depopulate(rv, m - rv->pages);
1039 vm_reserv_unlock(rv);
1045 * Initializes the reservation management system. Specifically, initializes
1046 * the reservation array.
1048 * Requires that vm_page_array and first_page are initialized!
1051 vm_reserv_init(void)
1054 struct vm_phys_seg *seg;
1055 struct vm_reserv *rv;
1056 struct vm_reserv_domain *rvd;
1060 * Initialize the reservation array. Specifically, initialize the
1061 * "pages" field for every element that has an underlying superpage.
1063 for (segind = 0; segind < vm_phys_nsegs; segind++) {
1064 seg = &vm_phys_segs[segind];
1065 paddr = roundup2(seg->start, VM_LEVEL_0_SIZE);
1066 while (paddr + VM_LEVEL_0_SIZE > paddr && paddr +
1067 VM_LEVEL_0_SIZE <= seg->end) {
1068 rv = &vm_reserv_array[paddr >> VM_LEVEL_0_SHIFT];
1069 rv->pages = PHYS_TO_VM_PAGE(paddr);
1070 rv->domain = seg->domain;
1071 mtx_init(&rv->lock, "vm reserv", NULL, MTX_DEF);
1072 paddr += VM_LEVEL_0_SIZE;
1075 for (i = 0; i < MAXMEMDOM; i++) {
1077 mtx_init(&rvd->lock, "vm reserv domain", NULL, MTX_DEF);
1078 TAILQ_INIT(&rvd->partpop);
1079 mtx_init(&rvd->marker.lock, "vm reserv marker", NULL, MTX_DEF);
1082 * Fully populated reservations should never be present in the
1083 * partially populated reservation queues.
1085 rvd->marker.popcnt = VM_LEVEL_0_NPAGES;
1086 for (j = 0; j < NBPOPMAP; j++)
1087 popmap_set(rvd->marker.popmap, j);
1090 for (i = 0; i < VM_RESERV_OBJ_LOCK_COUNT; i++)
1091 mtx_init(&vm_reserv_object_mtx[i], "resv obj lock", NULL,
1096 * Returns true if the given page belongs to a reservation and that page is
1097 * free. Otherwise, returns false.
1100 vm_reserv_is_page_free(vm_page_t m)
1104 rv = vm_reserv_from_page(m);
1105 if (rv->object == NULL)
1107 return (popmap_is_clear(rv->popmap, m - rv->pages));
1111 * If the given page belongs to a reservation, returns the level of that
1112 * reservation. Otherwise, returns -1.
1115 vm_reserv_level(vm_page_t m)
1119 rv = vm_reserv_from_page(m);
1120 return (rv->object != NULL ? 0 : -1);
1124 * Returns a reservation level if the given page belongs to a fully populated
1125 * reservation and -1 otherwise.
1128 vm_reserv_level_iffullpop(vm_page_t m)
1132 rv = vm_reserv_from_page(m);
1133 return (rv->popcnt == VM_LEVEL_0_NPAGES ? 0 : -1);
1137 * Remove a partially populated reservation from the queue.
1140 vm_reserv_dequeue(vm_reserv_t rv)
1143 vm_reserv_domain_assert_locked(rv->domain);
1144 vm_reserv_assert_locked(rv);
1145 CTR5(KTR_VM, "%s: rv %p object %p popcnt %d inpartpop %d",
1146 __FUNCTION__, rv, rv->object, rv->popcnt, rv->inpartpopq);
1147 KASSERT(rv->inpartpopq,
1148 ("vm_reserv_reclaim: reserv %p's inpartpopq is FALSE", rv));
1150 TAILQ_REMOVE(&vm_rvd[rv->domain].partpop, rv, partpopq);
1151 rv->inpartpopq = FALSE;
1155 * Breaks the given partially populated reservation, releasing its free pages
1156 * to the physical memory allocator.
1159 vm_reserv_reclaim(vm_reserv_t rv)
1162 vm_reserv_assert_locked(rv);
1163 CTR5(KTR_VM, "%s: rv %p object %p popcnt %d inpartpop %d",
1164 __FUNCTION__, rv, rv->object, rv->popcnt, rv->inpartpopq);
1165 if (rv->inpartpopq) {
1166 vm_reserv_domain_lock(rv->domain);
1167 vm_reserv_dequeue(rv);
1168 vm_reserv_domain_unlock(rv->domain);
1170 vm_reserv_break(rv);
1171 counter_u64_add(vm_reserv_reclaimed, 1);
1175 * Breaks a reservation near the head of the partially populated reservation
1176 * queue, releasing its free pages to the physical memory allocator. Returns
1177 * TRUE if a reservation is broken and FALSE otherwise.
1180 vm_reserv_reclaim_inactive(int domain)
1184 vm_reserv_domain_lock(domain);
1185 TAILQ_FOREACH(rv, &vm_rvd[domain].partpop, partpopq) {
1187 * A locked reservation is likely being updated or reclaimed,
1188 * so just skip ahead.
1190 if (rv != &vm_rvd[domain].marker && vm_reserv_trylock(rv)) {
1191 vm_reserv_dequeue(rv);
1195 vm_reserv_domain_unlock(domain);
1197 vm_reserv_reclaim(rv);
1198 vm_reserv_unlock(rv);
1205 * Determine whether this reservation has free pages that satisfy the given
1206 * request for contiguous physical memory. Start searching from the lower
1207 * bound, defined by low_index.
1210 vm_reserv_test_contig(vm_reserv_t rv, u_long npages, vm_paddr_t low,
1211 vm_paddr_t high, u_long alignment, vm_paddr_t boundary)
1213 vm_paddr_t pa, size;
1215 int bitpos, bits_left, i, hi, lo, n;
1217 vm_reserv_assert_locked(rv);
1218 size = npages << PAGE_SHIFT;
1219 pa = VM_PAGE_TO_PHYS(&rv->pages[0]);
1221 ((low + PAGE_MASK - pa) >> PAGE_SHIFT) : 0;
1223 changes = rv->popmap[i] | ((1UL << (lo % NBPOPMAP)) - 1);
1224 hi = (pa + VM_LEVEL_0_SIZE > high) ?
1225 ((high + PAGE_MASK - pa) >> PAGE_SHIFT) : VM_LEVEL_0_NPAGES;
1227 bits_left = hi % NBPOPMAP;
1231 * "changes" is a bitmask that marks where a new sequence of
1232 * 0s or 1s begins in popmap[i], with last bit in popmap[i-1]
1233 * considered to be 1 if and only if lo == hi. The bits of
1234 * popmap[-1] and popmap[NPOPMAP] are considered all 1s.
1236 changes ^= (changes << 1) | (lo == hi);
1237 while (changes != 0) {
1239 * If the next change marked begins a run of 0s, set
1240 * lo to mark that position. Otherwise set hi and
1241 * look for a satisfactory first page from lo up to hi.
1243 bitpos = ffsl(changes) - 1;
1244 changes ^= 1UL << bitpos;
1246 lo = NBPOPMAP * i + bitpos;
1249 hi = NBPOPMAP * i + bitpos;
1250 pa = VM_PAGE_TO_PHYS(&rv->pages[lo]);
1251 if ((pa & (alignment - 1)) != 0) {
1252 /* Skip to next aligned page. */
1253 lo += (((pa - 1) | (alignment - 1)) + 1) >>
1255 if (lo >= VM_LEVEL_0_NPAGES)
1257 pa = VM_PAGE_TO_PHYS(&rv->pages[lo]);
1259 if (((pa ^ (pa + size - 1)) & ~(boundary - 1)) != 0) {
1260 /* Skip to next boundary-matching page. */
1261 lo += (((pa - 1) | (boundary - 1)) + 1) >>
1263 if (lo >= VM_LEVEL_0_NPAGES)
1265 pa = VM_PAGE_TO_PHYS(&rv->pages[lo]);
1267 if (lo * PAGE_SIZE + size <= hi * PAGE_SIZE)
1272 changes = rv->popmap[i];
1274 changes = bits_left == 0 ? -1UL :
1275 (rv->popmap[n] | (-1UL << bits_left));
1282 * Searches the partially populated reservation queue for the least recently
1283 * changed reservation with free pages that satisfy the given request for
1284 * contiguous physical memory. If a satisfactory reservation is found, it is
1285 * broken. Returns true if a reservation is broken and false otherwise.
1288 vm_reserv_reclaim_contig(int domain, u_long npages, vm_paddr_t low,
1289 vm_paddr_t high, u_long alignment, vm_paddr_t boundary)
1291 struct vm_reserv_queue *queue;
1292 vm_paddr_t pa, size;
1293 vm_reserv_t marker, rv, rvn;
1295 if (npages > VM_LEVEL_0_NPAGES - 1)
1297 marker = &vm_rvd[domain].marker;
1298 queue = &vm_rvd[domain].partpop;
1299 size = npages << PAGE_SHIFT;
1301 vm_reserv_domain_scan_lock(domain);
1302 vm_reserv_domain_lock(domain);
1303 TAILQ_FOREACH_SAFE(rv, queue, partpopq, rvn) {
1304 pa = VM_PAGE_TO_PHYS(&rv->pages[0]);
1305 if (pa + VM_LEVEL_0_SIZE - size < low) {
1306 /* This entire reservation is too low; go to next. */
1309 if (pa + size > high) {
1310 /* This entire reservation is too high; go to next. */
1314 if (vm_reserv_trylock(rv) == 0) {
1315 TAILQ_INSERT_AFTER(queue, rv, marker, partpopq);
1316 vm_reserv_domain_unlock(domain);
1318 if (!rv->inpartpopq ||
1319 TAILQ_NEXT(rv, partpopq) != marker) {
1320 vm_reserv_unlock(rv);
1321 vm_reserv_domain_lock(domain);
1322 rvn = TAILQ_NEXT(marker, partpopq);
1323 TAILQ_REMOVE(queue, marker, partpopq);
1326 vm_reserv_domain_lock(domain);
1327 TAILQ_REMOVE(queue, marker, partpopq);
1329 vm_reserv_domain_unlock(domain);
1330 if (vm_reserv_test_contig(rv, npages, low, high,
1331 alignment, boundary)) {
1332 vm_reserv_domain_scan_unlock(domain);
1333 vm_reserv_reclaim(rv);
1334 vm_reserv_unlock(rv);
1337 vm_reserv_unlock(rv);
1338 vm_reserv_domain_lock(domain);
1340 vm_reserv_domain_unlock(domain);
1341 vm_reserv_domain_scan_unlock(domain);
1346 * Transfers the reservation underlying the given page to a new object.
1348 * The object must be locked.
1351 vm_reserv_rename(vm_page_t m, vm_object_t new_object, vm_object_t old_object,
1352 vm_pindex_t old_object_offset)
1356 VM_OBJECT_ASSERT_WLOCKED(new_object);
1357 rv = vm_reserv_from_page(m);
1358 if (rv->object == old_object) {
1361 "%s: rv %p object %p new %p popcnt %d inpartpop %d",
1362 __FUNCTION__, rv, rv->object, new_object, rv->popcnt,
1364 if (rv->object == old_object) {
1365 vm_reserv_object_lock(old_object);
1367 LIST_REMOVE(rv, objq);
1368 vm_reserv_object_unlock(old_object);
1369 vm_reserv_object_lock(new_object);
1370 rv->object = new_object;
1371 rv->pindex -= old_object_offset;
1372 LIST_INSERT_HEAD(&new_object->rvq, rv, objq);
1373 vm_reserv_object_unlock(new_object);
1375 vm_reserv_unlock(rv);
1380 * Returns the size (in bytes) of a reservation of the specified level.
1383 vm_reserv_size(int level)
1388 return (VM_LEVEL_0_SIZE);
1397 * Allocates the virtual and physical memory required by the reservation
1398 * management system's data structures, in particular, the reservation array.
1401 vm_reserv_startup(vm_offset_t *vaddr, vm_paddr_t end)
1403 vm_paddr_t new_end, high_water;
1407 high_water = phys_avail[1];
1408 for (i = 0; i < vm_phys_nsegs; i++) {
1409 if (vm_phys_segs[i].end > high_water)
1410 high_water = vm_phys_segs[i].end;
1413 /* Skip the first chunk. It is already accounted for. */
1414 for (i = 2; phys_avail[i + 1] != 0; i += 2) {
1415 if (phys_avail[i + 1] > high_water)
1416 high_water = phys_avail[i + 1];
1420 * Calculate the size (in bytes) of the reservation array. Round up
1421 * from "high_water" because every small page is mapped to an element
1422 * in the reservation array based on its physical address. Thus, the
1423 * number of elements in the reservation array can be greater than the
1424 * number of superpages.
1426 size = howmany(high_water, VM_LEVEL_0_SIZE) * sizeof(struct vm_reserv);
1429 * Allocate and map the physical memory for the reservation array. The
1430 * next available virtual address is returned by reference.
1432 new_end = end - round_page(size);
1433 vm_reserv_array = (void *)(uintptr_t)pmap_map(vaddr, new_end, end,
1434 VM_PROT_READ | VM_PROT_WRITE);
1435 bzero(vm_reserv_array, size);
1438 * Return the next available physical address.
1444 * Returns the superpage containing the given page.
1447 vm_reserv_to_superpage(vm_page_t m)
1451 VM_OBJECT_ASSERT_LOCKED(m->object);
1452 rv = vm_reserv_from_page(m);
1453 if (rv->object == m->object && rv->popcnt == VM_LEVEL_0_NPAGES)
1461 #endif /* VM_NRESERVLEVEL > 0 */