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, 0, "Reservation Info");
266 static counter_u64_t vm_reserv_broken = EARLY_COUNTER;
267 SYSCTL_COUNTER_U64(_vm_reserv, OID_AUTO, broken, CTLFLAG_RD,
268 &vm_reserv_broken, "Cumulative number of broken reservations");
270 static counter_u64_t vm_reserv_freed = EARLY_COUNTER;
271 SYSCTL_COUNTER_U64(_vm_reserv, OID_AUTO, freed, CTLFLAG_RD,
272 &vm_reserv_freed, "Cumulative number of freed reservations");
274 static int sysctl_vm_reserv_fullpop(SYSCTL_HANDLER_ARGS);
276 SYSCTL_PROC(_vm_reserv, OID_AUTO, fullpop, CTLTYPE_INT | CTLFLAG_RD, NULL, 0,
277 sysctl_vm_reserv_fullpop, "I", "Current number of full reservations");
279 static int sysctl_vm_reserv_partpopq(SYSCTL_HANDLER_ARGS);
281 SYSCTL_OID(_vm_reserv, OID_AUTO, partpopq, CTLTYPE_STRING | CTLFLAG_RD, NULL, 0,
282 sysctl_vm_reserv_partpopq, "A", "Partially populated reservation queues");
284 static counter_u64_t vm_reserv_reclaimed = EARLY_COUNTER;
285 SYSCTL_COUNTER_U64(_vm_reserv, OID_AUTO, reclaimed, CTLFLAG_RD,
286 &vm_reserv_reclaimed, "Cumulative number of reclaimed reservations");
289 * The object lock pool is used to synchronize the rvq. We can not use a
290 * pool mutex because it is required before malloc works.
292 * The "hash" function could be made faster without divide and modulo.
294 #define VM_RESERV_OBJ_LOCK_COUNT MAXCPU
296 struct mtx_padalign vm_reserv_object_mtx[VM_RESERV_OBJ_LOCK_COUNT];
298 #define vm_reserv_object_lock_idx(object) \
299 (((uintptr_t)object / sizeof(*object)) % VM_RESERV_OBJ_LOCK_COUNT)
300 #define vm_reserv_object_lock_ptr(object) \
301 &vm_reserv_object_mtx[vm_reserv_object_lock_idx((object))]
302 #define vm_reserv_object_lock(object) \
303 mtx_lock(vm_reserv_object_lock_ptr((object)))
304 #define vm_reserv_object_unlock(object) \
305 mtx_unlock(vm_reserv_object_lock_ptr((object)))
307 static void vm_reserv_break(vm_reserv_t rv);
308 static void vm_reserv_depopulate(vm_reserv_t rv, int index);
309 static vm_reserv_t vm_reserv_from_page(vm_page_t m);
310 static boolean_t vm_reserv_has_pindex(vm_reserv_t rv,
312 static void vm_reserv_populate(vm_reserv_t rv, int index);
313 static void vm_reserv_reclaim(vm_reserv_t rv);
316 * Returns the current number of full reservations.
318 * Since the number of full reservations is computed without acquiring any
319 * locks, the returned value is inexact.
322 sysctl_vm_reserv_fullpop(SYSCTL_HANDLER_ARGS)
325 struct vm_phys_seg *seg;
330 for (segind = 0; segind < vm_phys_nsegs; segind++) {
331 seg = &vm_phys_segs[segind];
332 paddr = roundup2(seg->start, VM_LEVEL_0_SIZE);
333 while (paddr + VM_LEVEL_0_SIZE > paddr && paddr +
334 VM_LEVEL_0_SIZE <= seg->end) {
335 rv = &vm_reserv_array[paddr >> VM_LEVEL_0_SHIFT];
336 fullpop += rv->popcnt == VM_LEVEL_0_NPAGES;
337 paddr += VM_LEVEL_0_SIZE;
340 return (sysctl_handle_int(oidp, &fullpop, 0, req));
344 * Describes the current state of the partially populated reservation queue.
347 sysctl_vm_reserv_partpopq(SYSCTL_HANDLER_ARGS)
351 int counter, error, domain, level, unused_pages;
353 error = sysctl_wire_old_buffer(req, 0);
356 sbuf_new_for_sysctl(&sbuf, NULL, 128, req);
357 sbuf_printf(&sbuf, "\nDOMAIN LEVEL SIZE NUMBER\n\n");
358 for (domain = 0; domain < vm_ndomains; domain++) {
359 for (level = -1; level <= VM_NRESERVLEVEL - 2; level++) {
362 vm_reserv_domain_lock(domain);
363 TAILQ_FOREACH(rv, &vm_rvd[domain].partpop, partpopq) {
364 if (rv == &vm_rvd[domain].marker)
367 unused_pages += VM_LEVEL_0_NPAGES - rv->popcnt;
369 vm_reserv_domain_unlock(domain);
370 sbuf_printf(&sbuf, "%6d, %7d, %6dK, %6d\n",
372 unused_pages * ((int)PAGE_SIZE / 1024), counter);
375 error = sbuf_finish(&sbuf);
381 * Remove a reservation from the object's objq.
384 vm_reserv_remove(vm_reserv_t rv)
388 vm_reserv_assert_locked(rv);
389 CTR5(KTR_VM, "%s: rv %p object %p popcnt %d inpartpop %d",
390 __FUNCTION__, rv, rv->object, rv->popcnt, rv->inpartpopq);
391 KASSERT(rv->object != NULL,
392 ("vm_reserv_remove: reserv %p is free", rv));
393 KASSERT(!rv->inpartpopq,
394 ("vm_reserv_remove: reserv %p's inpartpopq is TRUE", rv));
396 vm_reserv_object_lock(object);
397 LIST_REMOVE(rv, objq);
399 vm_reserv_object_unlock(object);
403 * Insert a new reservation into the object's objq.
406 vm_reserv_insert(vm_reserv_t rv, vm_object_t object, vm_pindex_t pindex)
410 vm_reserv_assert_locked(rv);
412 "%s: rv %p(%p) object %p new %p popcnt %d",
413 __FUNCTION__, rv, rv->pages, rv->object, object,
415 KASSERT(rv->object == NULL,
416 ("vm_reserv_insert: reserv %p isn't free", rv));
417 KASSERT(rv->popcnt == 0,
418 ("vm_reserv_insert: reserv %p's popcnt is corrupted", rv));
419 KASSERT(!rv->inpartpopq,
420 ("vm_reserv_insert: reserv %p's inpartpopq is TRUE", rv));
421 for (i = 0; i < NPOPMAP; i++)
422 KASSERT(rv->popmap[i] == 0,
423 ("vm_reserv_insert: reserv %p's popmap is corrupted", rv));
424 vm_reserv_object_lock(object);
427 rv->lasttick = ticks;
428 LIST_INSERT_HEAD(&object->rvq, rv, objq);
429 vm_reserv_object_unlock(object);
433 * Reduces the given reservation's population count. If the population count
434 * becomes zero, the reservation is destroyed. Additionally, moves the
435 * reservation to the tail of the partially populated reservation queue if the
436 * population count is non-zero.
439 vm_reserv_depopulate(vm_reserv_t rv, int index)
441 struct vm_domain *vmd;
443 vm_reserv_assert_locked(rv);
444 CTR5(KTR_VM, "%s: rv %p object %p popcnt %d inpartpop %d",
445 __FUNCTION__, rv, rv->object, rv->popcnt, rv->inpartpopq);
446 KASSERT(rv->object != NULL,
447 ("vm_reserv_depopulate: reserv %p is free", rv));
448 KASSERT(popmap_is_set(rv->popmap, index),
449 ("vm_reserv_depopulate: reserv %p's popmap[%d] is clear", rv,
451 KASSERT(rv->popcnt > 0,
452 ("vm_reserv_depopulate: reserv %p's popcnt is corrupted", rv));
453 KASSERT(rv->domain < vm_ndomains,
454 ("vm_reserv_depopulate: reserv %p's domain is corrupted %d",
456 if (rv->popcnt == VM_LEVEL_0_NPAGES) {
457 KASSERT(rv->pages->psind == 1,
458 ("vm_reserv_depopulate: reserv %p is already demoted",
460 rv->pages->psind = 0;
462 popmap_clear(rv->popmap, index);
464 if ((unsigned)(ticks - rv->lasttick) >= PARTPOPSLOP ||
466 vm_reserv_domain_lock(rv->domain);
467 if (rv->inpartpopq) {
468 TAILQ_REMOVE(&vm_rvd[rv->domain].partpop, rv, partpopq);
469 rv->inpartpopq = FALSE;
471 if (rv->popcnt != 0) {
472 rv->inpartpopq = TRUE;
473 TAILQ_INSERT_TAIL(&vm_rvd[rv->domain].partpop, rv,
476 vm_reserv_domain_unlock(rv->domain);
477 rv->lasttick = ticks;
479 vmd = VM_DOMAIN(rv->domain);
480 if (rv->popcnt == 0) {
481 vm_reserv_remove(rv);
482 vm_domain_free_lock(vmd);
483 vm_phys_free_pages(rv->pages, VM_LEVEL_0_ORDER);
484 vm_domain_free_unlock(vmd);
485 counter_u64_add(vm_reserv_freed, 1);
487 vm_domain_freecnt_inc(vmd, 1);
491 * Returns the reservation to which the given page might belong.
493 static __inline vm_reserv_t
494 vm_reserv_from_page(vm_page_t m)
497 return (&vm_reserv_array[VM_PAGE_TO_PHYS(m) >> VM_LEVEL_0_SHIFT]);
501 * Returns an existing reservation or NULL and initialized successor pointer.
504 vm_reserv_from_object(vm_object_t object, vm_pindex_t pindex,
505 vm_page_t mpred, vm_page_t *msuccp)
512 KASSERT(mpred->object == object,
513 ("vm_reserv_from_object: object doesn't contain mpred"));
514 KASSERT(mpred->pindex < pindex,
515 ("vm_reserv_from_object: mpred doesn't precede pindex"));
516 rv = vm_reserv_from_page(mpred);
517 if (rv->object == object && vm_reserv_has_pindex(rv, pindex))
519 msucc = TAILQ_NEXT(mpred, listq);
521 msucc = TAILQ_FIRST(&object->memq);
523 KASSERT(msucc->pindex > pindex,
524 ("vm_reserv_from_object: msucc doesn't succeed pindex"));
525 rv = vm_reserv_from_page(msucc);
526 if (rv->object == object && vm_reserv_has_pindex(rv, pindex))
538 * Returns TRUE if the given reservation contains the given page index and
541 static __inline boolean_t
542 vm_reserv_has_pindex(vm_reserv_t rv, vm_pindex_t pindex)
545 return (((pindex - rv->pindex) & ~(VM_LEVEL_0_NPAGES - 1)) == 0);
549 * Increases the given reservation's population count. Moves the reservation
550 * to the tail of the partially populated reservation queue.
553 vm_reserv_populate(vm_reserv_t rv, int index)
556 vm_reserv_assert_locked(rv);
557 CTR5(KTR_VM, "%s: rv %p object %p popcnt %d inpartpop %d",
558 __FUNCTION__, rv, rv->object, rv->popcnt, rv->inpartpopq);
559 KASSERT(rv->object != NULL,
560 ("vm_reserv_populate: reserv %p is free", rv));
561 KASSERT(popmap_is_clear(rv->popmap, index),
562 ("vm_reserv_populate: reserv %p's popmap[%d] is set", rv,
564 KASSERT(rv->popcnt < VM_LEVEL_0_NPAGES,
565 ("vm_reserv_populate: reserv %p is already full", rv));
566 KASSERT(rv->pages->psind == 0,
567 ("vm_reserv_populate: reserv %p is already promoted", rv));
568 KASSERT(rv->domain < vm_ndomains,
569 ("vm_reserv_populate: reserv %p's domain is corrupted %d",
571 popmap_set(rv->popmap, index);
573 if ((unsigned)(ticks - rv->lasttick) < PARTPOPSLOP &&
574 rv->inpartpopq && rv->popcnt != VM_LEVEL_0_NPAGES)
576 rv->lasttick = ticks;
577 vm_reserv_domain_lock(rv->domain);
578 if (rv->inpartpopq) {
579 TAILQ_REMOVE(&vm_rvd[rv->domain].partpop, rv, partpopq);
580 rv->inpartpopq = FALSE;
582 if (rv->popcnt < VM_LEVEL_0_NPAGES) {
583 rv->inpartpopq = TRUE;
584 TAILQ_INSERT_TAIL(&vm_rvd[rv->domain].partpop, rv, partpopq);
586 KASSERT(rv->pages->psind == 0,
587 ("vm_reserv_populate: reserv %p is already promoted",
589 rv->pages->psind = 1;
591 vm_reserv_domain_unlock(rv->domain);
595 * Allocates a contiguous set of physical pages of the given size "npages"
596 * from existing or newly created reservations. All of the physical pages
597 * must be at or above the given physical address "low" and below the given
598 * physical address "high". The given value "alignment" determines the
599 * alignment of the first physical page in the set. If the given value
600 * "boundary" is non-zero, then the set of physical pages cannot cross any
601 * physical address boundary that is a multiple of that value. Both
602 * "alignment" and "boundary" must be a power of two.
604 * The page "mpred" must immediately precede the offset "pindex" within the
607 * The object must be locked.
610 vm_reserv_alloc_contig(vm_object_t object, vm_pindex_t pindex, int domain,
611 int req, vm_page_t mpred, u_long npages, vm_paddr_t low, vm_paddr_t high,
612 u_long alignment, vm_paddr_t boundary)
614 struct vm_domain *vmd;
616 vm_page_t m, m_ret, msucc;
617 vm_pindex_t first, leftcap, rightcap;
619 u_long allocpages, maxpages, minpages;
622 VM_OBJECT_ASSERT_WLOCKED(object);
623 KASSERT(npages != 0, ("vm_reserv_alloc_contig: npages is 0"));
626 * Is a reservation fundamentally impossible?
628 if (pindex < VM_RESERV_INDEX(object, pindex) ||
629 pindex + npages > object->size)
633 * All reservations of a particular size have the same alignment.
634 * Assuming that the first page is allocated from a reservation, the
635 * least significant bits of its physical address can be determined
636 * from its offset from the beginning of the reservation and the size
637 * of the reservation.
639 * Could the specified index within a reservation of the smallest
640 * possible size satisfy the alignment and boundary requirements?
642 pa = VM_RESERV_INDEX(object, pindex) << PAGE_SHIFT;
643 if ((pa & (alignment - 1)) != 0)
645 size = npages << PAGE_SHIFT;
646 if (((pa ^ (pa + size - 1)) & ~(boundary - 1)) != 0)
650 * Look for an existing reservation.
652 rv = vm_reserv_from_object(object, pindex, mpred, &msucc);
654 KASSERT(object != kernel_object || rv->domain == domain,
655 ("vm_reserv_alloc_contig: domain mismatch"));
656 index = VM_RESERV_INDEX(object, pindex);
657 /* Does the allocation fit within the reservation? */
658 if (index + npages > VM_LEVEL_0_NPAGES)
661 vmd = VM_DOMAIN(domain);
663 /* Handle reclaim race. */
664 if (rv->object != object)
666 m = &rv->pages[index];
667 pa = VM_PAGE_TO_PHYS(m);
668 if (pa < low || pa + size > high ||
669 (pa & (alignment - 1)) != 0 ||
670 ((pa ^ (pa + size - 1)) & ~(boundary - 1)) != 0)
672 /* Handle vm_page_rename(m, new_object, ...). */
673 for (i = 0; i < npages; i++)
674 if (popmap_is_set(rv->popmap, index + i))
676 if (!vm_domain_allocate(vmd, req, npages))
678 for (i = 0; i < npages; i++)
679 vm_reserv_populate(rv, index + i);
680 vm_reserv_unlock(rv);
683 vm_reserv_unlock(rv);
688 * Could at least one reservation fit between the first index to the
689 * left that can be used ("leftcap") and the first index to the right
690 * that cannot be used ("rightcap")?
692 * We must synchronize with the reserv object lock to protect the
693 * pindex/object of the resulting reservations against rename while
696 first = pindex - VM_RESERV_INDEX(object, pindex);
697 minpages = VM_RESERV_INDEX(object, pindex) + npages;
698 maxpages = roundup2(minpages, VM_LEVEL_0_NPAGES);
699 allocpages = maxpages;
700 vm_reserv_object_lock(object);
702 if ((rv = vm_reserv_from_page(mpred))->object != object)
703 leftcap = mpred->pindex + 1;
705 leftcap = rv->pindex + VM_LEVEL_0_NPAGES;
706 if (leftcap > first) {
707 vm_reserv_object_unlock(object);
712 if ((rv = vm_reserv_from_page(msucc))->object != object)
713 rightcap = msucc->pindex;
715 rightcap = rv->pindex;
716 if (first + maxpages > rightcap) {
717 if (maxpages == VM_LEVEL_0_NPAGES) {
718 vm_reserv_object_unlock(object);
723 * At least one reservation will fit between "leftcap"
724 * and "rightcap". However, a reservation for the
725 * last of the requested pages will not fit. Reduce
726 * the size of the upcoming allocation accordingly.
728 allocpages = minpages;
731 vm_reserv_object_unlock(object);
734 * Would the last new reservation extend past the end of the object?
736 * If the object is unlikely to grow don't allocate a reservation for
739 if ((object->flags & OBJ_ANON) == 0 &&
740 first + maxpages > object->size) {
741 if (maxpages == VM_LEVEL_0_NPAGES)
743 allocpages = minpages;
747 * Allocate the physical pages. The alignment and boundary specified
748 * for this allocation may be different from the alignment and
749 * boundary specified for the requested pages. For instance, the
750 * specified index may not be the first page within the first new
754 vmd = VM_DOMAIN(domain);
755 if (vm_domain_allocate(vmd, req, npages)) {
756 vm_domain_free_lock(vmd);
757 m = vm_phys_alloc_contig(domain, allocpages, low, high,
758 ulmax(alignment, VM_LEVEL_0_SIZE),
759 boundary > VM_LEVEL_0_SIZE ? boundary : 0);
760 vm_domain_free_unlock(vmd);
762 vm_domain_freecnt_inc(vmd, npages);
767 KASSERT(vm_phys_domain(m) == domain,
768 ("vm_reserv_alloc_contig: Page domain does not match requested."));
771 * The allocated physical pages always begin at a reservation
772 * boundary, but they do not always end at a reservation boundary.
773 * Initialize every reservation that is completely covered by the
774 * allocated physical pages.
777 index = VM_RESERV_INDEX(object, pindex);
779 rv = vm_reserv_from_page(m);
780 KASSERT(rv->pages == m,
781 ("vm_reserv_alloc_contig: reserv %p's pages is corrupted",
784 vm_reserv_insert(rv, object, first);
785 n = ulmin(VM_LEVEL_0_NPAGES - index, npages);
786 for (i = 0; i < n; i++)
787 vm_reserv_populate(rv, index + i);
790 m_ret = &rv->pages[index];
793 vm_reserv_unlock(rv);
794 m += VM_LEVEL_0_NPAGES;
795 first += VM_LEVEL_0_NPAGES;
796 allocpages -= VM_LEVEL_0_NPAGES;
797 } while (allocpages >= VM_LEVEL_0_NPAGES);
802 * Allocate a physical page from an existing or newly created reservation.
804 * The page "mpred" must immediately precede the offset "pindex" within the
807 * The object must be locked.
810 vm_reserv_alloc_page(vm_object_t object, vm_pindex_t pindex, int domain,
811 int req, vm_page_t mpred)
813 struct vm_domain *vmd;
815 vm_pindex_t first, leftcap, rightcap;
819 VM_OBJECT_ASSERT_WLOCKED(object);
822 * Is a reservation fundamentally impossible?
824 if (pindex < VM_RESERV_INDEX(object, pindex) ||
825 pindex >= object->size)
829 * Look for an existing reservation.
831 rv = vm_reserv_from_object(object, pindex, mpred, &msucc);
833 KASSERT(object != kernel_object || rv->domain == domain,
834 ("vm_reserv_alloc_page: domain mismatch"));
836 vmd = VM_DOMAIN(domain);
837 index = VM_RESERV_INDEX(object, pindex);
838 m = &rv->pages[index];
840 /* Handle reclaim race. */
841 if (rv->object != object ||
842 /* Handle vm_page_rename(m, new_object, ...). */
843 popmap_is_set(rv->popmap, index)) {
847 if (vm_domain_allocate(vmd, req, 1) == 0)
850 vm_reserv_populate(rv, index);
852 vm_reserv_unlock(rv);
857 * Could a reservation fit between the first index to the left that
858 * can be used and the first index to the right that cannot be used?
860 * We must synchronize with the reserv object lock to protect the
861 * pindex/object of the resulting reservations against rename while
864 first = pindex - VM_RESERV_INDEX(object, pindex);
865 vm_reserv_object_lock(object);
867 if ((rv = vm_reserv_from_page(mpred))->object != object)
868 leftcap = mpred->pindex + 1;
870 leftcap = rv->pindex + VM_LEVEL_0_NPAGES;
871 if (leftcap > first) {
872 vm_reserv_object_unlock(object);
877 if ((rv = vm_reserv_from_page(msucc))->object != object)
878 rightcap = msucc->pindex;
880 rightcap = rv->pindex;
881 if (first + VM_LEVEL_0_NPAGES > rightcap) {
882 vm_reserv_object_unlock(object);
886 vm_reserv_object_unlock(object);
889 * Would the last new reservation extend past the end of the object?
891 * If the object is unlikely to grow don't allocate a reservation for
894 if ((object->flags & OBJ_ANON) == 0 &&
895 first + VM_LEVEL_0_NPAGES > object->size)
899 * Allocate and populate the new reservation.
902 vmd = VM_DOMAIN(domain);
903 if (vm_domain_allocate(vmd, req, 1)) {
904 vm_domain_free_lock(vmd);
905 m = vm_phys_alloc_pages(domain, VM_FREEPOOL_DEFAULT,
907 vm_domain_free_unlock(vmd);
909 vm_domain_freecnt_inc(vmd, 1);
914 rv = vm_reserv_from_page(m);
916 KASSERT(rv->pages == m,
917 ("vm_reserv_alloc_page: reserv %p's pages is corrupted", rv));
918 vm_reserv_insert(rv, object, first);
919 index = VM_RESERV_INDEX(object, pindex);
920 vm_reserv_populate(rv, index);
921 vm_reserv_unlock(rv);
923 return (&rv->pages[index]);
927 * Breaks the given reservation. All free pages in the reservation
928 * are returned to the physical memory allocator. The reservation's
929 * population count and map are reset to their initial state.
931 * The given reservation must not be in the partially populated reservation
935 vm_reserv_break(vm_reserv_t rv)
938 int bitpos, hi, i, lo;
940 vm_reserv_assert_locked(rv);
941 CTR5(KTR_VM, "%s: rv %p object %p popcnt %d inpartpop %d",
942 __FUNCTION__, rv, rv->object, rv->popcnt, rv->inpartpopq);
943 vm_reserv_remove(rv);
944 rv->pages->psind = 0;
946 for (i = 0; i <= NPOPMAP; i++) {
948 * "changes" is a bitmask that marks where a new sequence of
949 * 0s or 1s begins in popmap[i], with last bit in popmap[i-1]
950 * considered to be 1 if and only if lo == hi. The bits of
951 * popmap[-1] and popmap[NPOPMAP] are considered all 1s.
956 changes = rv->popmap[i];
957 changes ^= (changes << 1) | (lo == hi);
960 while (changes != 0) {
962 * If the next change marked begins a run of 0s, set
963 * lo to mark that position. Otherwise set hi and
964 * free pages from lo up to hi.
966 bitpos = ffsl(changes) - 1;
967 changes ^= 1UL << bitpos;
969 lo = NBPOPMAP * i + bitpos;
971 hi = NBPOPMAP * i + bitpos;
972 vm_domain_free_lock(VM_DOMAIN(rv->domain));
973 vm_phys_enqueue_contig(&rv->pages[lo], hi - lo);
974 vm_domain_free_unlock(VM_DOMAIN(rv->domain));
980 counter_u64_add(vm_reserv_broken, 1);
984 * Breaks all reservations belonging to the given object.
987 vm_reserv_break_all(vm_object_t object)
992 * This access of object->rvq is unsynchronized so that the
993 * object rvq lock can nest after the domain_free lock. We
994 * must check for races in the results. However, the object
995 * lock prevents new additions, so we are guaranteed that when
996 * it returns NULL the object is properly empty.
998 while ((rv = LIST_FIRST(&object->rvq)) != NULL) {
1001 if (rv->object != object) {
1002 vm_reserv_unlock(rv);
1005 vm_reserv_domain_lock(rv->domain);
1006 if (rv->inpartpopq) {
1007 TAILQ_REMOVE(&vm_rvd[rv->domain].partpop, rv, partpopq);
1008 rv->inpartpopq = FALSE;
1010 vm_reserv_domain_unlock(rv->domain);
1011 vm_reserv_break(rv);
1012 vm_reserv_unlock(rv);
1017 * Frees the given page if it belongs to a reservation. Returns TRUE if the
1018 * page is freed and FALSE otherwise.
1021 vm_reserv_free_page(vm_page_t m)
1026 rv = vm_reserv_from_page(m);
1027 if (rv->object == NULL)
1030 /* Re-validate after lock. */
1031 if (rv->object != NULL) {
1032 vm_reserv_depopulate(rv, m - rv->pages);
1036 vm_reserv_unlock(rv);
1042 * Initializes the reservation management system. Specifically, initializes
1043 * the reservation array.
1045 * Requires that vm_page_array and first_page are initialized!
1048 vm_reserv_init(void)
1051 struct vm_phys_seg *seg;
1052 struct vm_reserv *rv;
1053 struct vm_reserv_domain *rvd;
1057 * Initialize the reservation array. Specifically, initialize the
1058 * "pages" field for every element that has an underlying superpage.
1060 for (segind = 0; segind < vm_phys_nsegs; segind++) {
1061 seg = &vm_phys_segs[segind];
1062 paddr = roundup2(seg->start, VM_LEVEL_0_SIZE);
1063 while (paddr + VM_LEVEL_0_SIZE > paddr && paddr +
1064 VM_LEVEL_0_SIZE <= seg->end) {
1065 rv = &vm_reserv_array[paddr >> VM_LEVEL_0_SHIFT];
1066 rv->pages = PHYS_TO_VM_PAGE(paddr);
1067 rv->domain = seg->domain;
1068 mtx_init(&rv->lock, "vm reserv", NULL, MTX_DEF);
1069 paddr += VM_LEVEL_0_SIZE;
1072 for (i = 0; i < MAXMEMDOM; i++) {
1074 mtx_init(&rvd->lock, "vm reserv domain", NULL, MTX_DEF);
1075 TAILQ_INIT(&rvd->partpop);
1076 mtx_init(&rvd->marker.lock, "vm reserv marker", NULL, MTX_DEF);
1079 * Fully populated reservations should never be present in the
1080 * partially populated reservation queues.
1082 rvd->marker.popcnt = VM_LEVEL_0_NPAGES;
1083 for (j = 0; j < NBPOPMAP; j++)
1084 popmap_set(rvd->marker.popmap, j);
1087 for (i = 0; i < VM_RESERV_OBJ_LOCK_COUNT; i++)
1088 mtx_init(&vm_reserv_object_mtx[i], "resv obj lock", NULL,
1093 * Returns true if the given page belongs to a reservation and that page is
1094 * free. Otherwise, returns false.
1097 vm_reserv_is_page_free(vm_page_t m)
1101 rv = vm_reserv_from_page(m);
1102 if (rv->object == NULL)
1104 return (popmap_is_clear(rv->popmap, m - rv->pages));
1108 * If the given page belongs to a reservation, returns the level of that
1109 * reservation. Otherwise, returns -1.
1112 vm_reserv_level(vm_page_t m)
1116 rv = vm_reserv_from_page(m);
1117 return (rv->object != NULL ? 0 : -1);
1121 * Returns a reservation level if the given page belongs to a fully populated
1122 * reservation and -1 otherwise.
1125 vm_reserv_level_iffullpop(vm_page_t m)
1129 rv = vm_reserv_from_page(m);
1130 return (rv->popcnt == VM_LEVEL_0_NPAGES ? 0 : -1);
1134 * Remove a partially populated reservation from the queue.
1137 vm_reserv_dequeue(vm_reserv_t rv)
1140 vm_reserv_domain_assert_locked(rv->domain);
1141 vm_reserv_assert_locked(rv);
1142 CTR5(KTR_VM, "%s: rv %p object %p popcnt %d inpartpop %d",
1143 __FUNCTION__, rv, rv->object, rv->popcnt, rv->inpartpopq);
1144 KASSERT(rv->inpartpopq,
1145 ("vm_reserv_reclaim: reserv %p's inpartpopq is FALSE", rv));
1147 TAILQ_REMOVE(&vm_rvd[rv->domain].partpop, rv, partpopq);
1148 rv->inpartpopq = FALSE;
1152 * Breaks the given partially populated reservation, releasing its free pages
1153 * to the physical memory allocator.
1156 vm_reserv_reclaim(vm_reserv_t rv)
1159 vm_reserv_assert_locked(rv);
1160 CTR5(KTR_VM, "%s: rv %p object %p popcnt %d inpartpop %d",
1161 __FUNCTION__, rv, rv->object, rv->popcnt, rv->inpartpopq);
1162 if (rv->inpartpopq) {
1163 vm_reserv_domain_lock(rv->domain);
1164 vm_reserv_dequeue(rv);
1165 vm_reserv_domain_unlock(rv->domain);
1167 vm_reserv_break(rv);
1168 counter_u64_add(vm_reserv_reclaimed, 1);
1172 * Breaks a reservation near the head of the partially populated reservation
1173 * queue, releasing its free pages to the physical memory allocator. Returns
1174 * TRUE if a reservation is broken and FALSE otherwise.
1177 vm_reserv_reclaim_inactive(int domain)
1181 vm_reserv_domain_lock(domain);
1182 TAILQ_FOREACH(rv, &vm_rvd[domain].partpop, partpopq) {
1184 * A locked reservation is likely being updated or reclaimed,
1185 * so just skip ahead.
1187 if (rv != &vm_rvd[domain].marker && vm_reserv_trylock(rv)) {
1188 vm_reserv_dequeue(rv);
1192 vm_reserv_domain_unlock(domain);
1194 vm_reserv_reclaim(rv);
1195 vm_reserv_unlock(rv);
1202 * Determine whether this reservation has free pages that satisfy the given
1203 * request for contiguous physical memory. Start searching from the lower
1204 * bound, defined by low_index.
1207 vm_reserv_test_contig(vm_reserv_t rv, u_long npages, vm_paddr_t low,
1208 vm_paddr_t high, u_long alignment, vm_paddr_t boundary)
1210 vm_paddr_t pa, size;
1212 int bitpos, bits_left, i, hi, lo, n;
1214 vm_reserv_assert_locked(rv);
1215 size = npages << PAGE_SHIFT;
1216 pa = VM_PAGE_TO_PHYS(&rv->pages[0]);
1218 ((low + PAGE_MASK - pa) >> PAGE_SHIFT) : 0;
1220 changes = rv->popmap[i] | ((1UL << (lo % NBPOPMAP)) - 1);
1221 hi = (pa + VM_LEVEL_0_SIZE > high) ?
1222 ((high + PAGE_MASK - pa) >> PAGE_SHIFT) : VM_LEVEL_0_NPAGES;
1224 bits_left = hi % NBPOPMAP;
1228 * "changes" is a bitmask that marks where a new sequence of
1229 * 0s or 1s begins in popmap[i], with last bit in popmap[i-1]
1230 * considered to be 1 if and only if lo == hi. The bits of
1231 * popmap[-1] and popmap[NPOPMAP] are considered all 1s.
1233 changes ^= (changes << 1) | (lo == hi);
1234 while (changes != 0) {
1236 * If the next change marked begins a run of 0s, set
1237 * lo to mark that position. Otherwise set hi and
1238 * look for a satisfactory first page from lo up to hi.
1240 bitpos = ffsl(changes) - 1;
1241 changes ^= 1UL << bitpos;
1243 lo = NBPOPMAP * i + bitpos;
1246 hi = NBPOPMAP * i + bitpos;
1247 pa = VM_PAGE_TO_PHYS(&rv->pages[lo]);
1248 if ((pa & (alignment - 1)) != 0) {
1249 /* Skip to next aligned page. */
1250 lo += (((pa - 1) | (alignment - 1)) + 1) >>
1252 if (lo >= VM_LEVEL_0_NPAGES)
1254 pa = VM_PAGE_TO_PHYS(&rv->pages[lo]);
1256 if (((pa ^ (pa + size - 1)) & ~(boundary - 1)) != 0) {
1257 /* Skip to next boundary-matching page. */
1258 lo += (((pa - 1) | (boundary - 1)) + 1) >>
1260 if (lo >= VM_LEVEL_0_NPAGES)
1262 pa = VM_PAGE_TO_PHYS(&rv->pages[lo]);
1264 if (lo * PAGE_SIZE + size <= hi * PAGE_SIZE)
1269 changes = rv->popmap[i];
1271 changes = bits_left == 0 ? -1UL :
1272 (rv->popmap[n] | (-1UL << bits_left));
1279 * Searches the partially populated reservation queue for the least recently
1280 * changed reservation with free pages that satisfy the given request for
1281 * contiguous physical memory. If a satisfactory reservation is found, it is
1282 * broken. Returns true if a reservation is broken and false otherwise.
1285 vm_reserv_reclaim_contig(int domain, u_long npages, vm_paddr_t low,
1286 vm_paddr_t high, u_long alignment, vm_paddr_t boundary)
1288 struct vm_reserv_queue *queue;
1289 vm_paddr_t pa, size;
1290 vm_reserv_t marker, rv, rvn;
1292 if (npages > VM_LEVEL_0_NPAGES - 1)
1294 marker = &vm_rvd[domain].marker;
1295 queue = &vm_rvd[domain].partpop;
1296 size = npages << PAGE_SHIFT;
1298 vm_reserv_domain_scan_lock(domain);
1299 vm_reserv_domain_lock(domain);
1300 TAILQ_FOREACH_SAFE(rv, queue, partpopq, rvn) {
1301 pa = VM_PAGE_TO_PHYS(&rv->pages[0]);
1302 if (pa + VM_LEVEL_0_SIZE - size < low) {
1303 /* This entire reservation is too low; go to next. */
1306 if (pa + size > high) {
1307 /* This entire reservation is too high; go to next. */
1311 if (vm_reserv_trylock(rv) == 0) {
1312 TAILQ_INSERT_AFTER(queue, rv, marker, partpopq);
1313 vm_reserv_domain_unlock(domain);
1315 if (!rv->inpartpopq ||
1316 TAILQ_NEXT(rv, partpopq) != marker) {
1317 vm_reserv_unlock(rv);
1318 vm_reserv_domain_lock(domain);
1319 rvn = TAILQ_NEXT(marker, partpopq);
1320 TAILQ_REMOVE(queue, marker, partpopq);
1323 vm_reserv_domain_lock(domain);
1324 TAILQ_REMOVE(queue, marker, partpopq);
1326 vm_reserv_domain_unlock(domain);
1327 if (vm_reserv_test_contig(rv, npages, low, high,
1328 alignment, boundary)) {
1329 vm_reserv_domain_scan_unlock(domain);
1330 vm_reserv_reclaim(rv);
1331 vm_reserv_unlock(rv);
1334 vm_reserv_unlock(rv);
1335 vm_reserv_domain_lock(domain);
1337 vm_reserv_domain_unlock(domain);
1338 vm_reserv_domain_scan_unlock(domain);
1343 * Transfers the reservation underlying the given page to a new object.
1345 * The object must be locked.
1348 vm_reserv_rename(vm_page_t m, vm_object_t new_object, vm_object_t old_object,
1349 vm_pindex_t old_object_offset)
1353 VM_OBJECT_ASSERT_WLOCKED(new_object);
1354 rv = vm_reserv_from_page(m);
1355 if (rv->object == old_object) {
1358 "%s: rv %p object %p new %p popcnt %d inpartpop %d",
1359 __FUNCTION__, rv, rv->object, new_object, rv->popcnt,
1361 if (rv->object == old_object) {
1362 vm_reserv_object_lock(old_object);
1364 LIST_REMOVE(rv, objq);
1365 vm_reserv_object_unlock(old_object);
1366 vm_reserv_object_lock(new_object);
1367 rv->object = new_object;
1368 rv->pindex -= old_object_offset;
1369 LIST_INSERT_HEAD(&new_object->rvq, rv, objq);
1370 vm_reserv_object_unlock(new_object);
1372 vm_reserv_unlock(rv);
1377 * Returns the size (in bytes) of a reservation of the specified level.
1380 vm_reserv_size(int level)
1385 return (VM_LEVEL_0_SIZE);
1394 * Allocates the virtual and physical memory required by the reservation
1395 * management system's data structures, in particular, the reservation array.
1398 vm_reserv_startup(vm_offset_t *vaddr, vm_paddr_t end)
1400 vm_paddr_t new_end, high_water;
1404 high_water = phys_avail[1];
1405 for (i = 0; i < vm_phys_nsegs; i++) {
1406 if (vm_phys_segs[i].end > high_water)
1407 high_water = vm_phys_segs[i].end;
1410 /* Skip the first chunk. It is already accounted for. */
1411 for (i = 2; phys_avail[i + 1] != 0; i += 2) {
1412 if (phys_avail[i + 1] > high_water)
1413 high_water = phys_avail[i + 1];
1417 * Calculate the size (in bytes) of the reservation array. Round up
1418 * from "high_water" because every small page is mapped to an element
1419 * in the reservation array based on its physical address. Thus, the
1420 * number of elements in the reservation array can be greater than the
1421 * number of superpages.
1423 size = howmany(high_water, VM_LEVEL_0_SIZE) * sizeof(struct vm_reserv);
1426 * Allocate and map the physical memory for the reservation array. The
1427 * next available virtual address is returned by reference.
1429 new_end = end - round_page(size);
1430 vm_reserv_array = (void *)(uintptr_t)pmap_map(vaddr, new_end, end,
1431 VM_PROT_READ | VM_PROT_WRITE);
1432 bzero(vm_reserv_array, size);
1435 * Return the next available physical address.
1441 * Initializes the reservation management system. Specifically, initializes
1442 * the reservation counters.
1445 vm_reserv_counter_init(void *unused)
1448 vm_reserv_freed = counter_u64_alloc(M_WAITOK);
1449 vm_reserv_broken = counter_u64_alloc(M_WAITOK);
1450 vm_reserv_reclaimed = counter_u64_alloc(M_WAITOK);
1452 SYSINIT(vm_reserv_counter_init, SI_SUB_CPU, SI_ORDER_ANY,
1453 vm_reserv_counter_init, NULL);
1456 * Returns the superpage containing the given page.
1459 vm_reserv_to_superpage(vm_page_t m)
1463 VM_OBJECT_ASSERT_LOCKED(m->object);
1464 rv = vm_reserv_from_page(m);
1465 if (rv->object == m->object && rv->popcnt == VM_LEVEL_0_NPAGES)
1473 #endif /* VM_NRESERVLEVEL > 0 */