sys/vm/vm_reserv.c

   1 /*-
   2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
   3  *
   4  * Copyright (c) 2002-2006 Rice University
   5  * Copyright (c) 2007-2011 Alan L. Cox <alc@cs.rice.edu>
   6  * All rights reserved.
   7  *
   8  * This software was developed for the FreeBSD Project by Alan L. Cox,
   9  * Olivier Crameri, Peter Druschel, Sitaram Iyer, and Juan Navarro.
  10  *
  11  * Redistribution and use in source and binary forms, with or without
  12  * modification, are permitted provided that the following conditions
  13  * are met:
  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.
  19  *
  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.
  32  */
  33
  34 /*
  35  *      Superpage reservation management module
  36  *
  37  * Any external functions defined by this module are only to be used by the
  38  * virtual memory system.
  39  */
  40
  41 #include <sys/cdefs.h>
  42 __FBSDID("$FreeBSD$");
  43
  44 #include "opt_vm.h"
  45
  46 #include <sys/param.h>
  47 #include <sys/kernel.h>
  48 #include <sys/lock.h>
  49 #include <sys/malloc.h>
  50 #include <sys/mutex.h>
  51 #include <sys/queue.h>
  52 #include <sys/rwlock.h>
  53 #include <sys/sbuf.h>
  54 #include <sys/sysctl.h>
  55 #include <sys/systm.h>
  56 #include <sys/counter.h>
  57 #include <sys/ktr.h>
  58 #include <sys/vmmeter.h>
  59 #include <sys/smp.h>
  60
  61 #include <vm/vm.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_pagequeue.h>
  67 #include <vm/vm_phys.h>
  68 #include <vm/vm_radix.h>
  69 #include <vm/vm_reserv.h>
  70
  71 /*
  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.
  76  */
  77
  78 #if VM_NRESERVLEVEL > 0
  79
  80 #ifndef VM_LEVEL_0_ORDER_MAX
  81 #define VM_LEVEL_0_ORDER_MAX    VM_LEVEL_0_ORDER
  82 #endif
  83
  84 /*
  85  * The number of small pages that are contained in a level 0 reservation
  86  */
  87 #define VM_LEVEL_0_NPAGES       (1 << VM_LEVEL_0_ORDER)
  88 #define VM_LEVEL_0_NPAGES_MAX   (1 << VM_LEVEL_0_ORDER_MAX)
  89
  90 /*
  91  * The number of bits by which a physical address is shifted to obtain the
  92  * reservation number
  93  */
  94 #define VM_LEVEL_0_SHIFT        (VM_LEVEL_0_ORDER + PAGE_SHIFT)
  95
  96 /*
  97  * The size of a level 0 reservation in bytes
  98  */
  99 #define VM_LEVEL_0_SIZE         (1 << VM_LEVEL_0_SHIFT)
 100
 101 /*
 102  * Computes the index of the small page underlying the given (object, pindex)
 103  * within the reservation's array of small pages.
 104  */
 105 #define VM_RESERV_INDEX(object, pindex) \
 106     (((object)->pg_color + (pindex)) & (VM_LEVEL_0_NPAGES - 1))
 107
 108 /*
 109  * The size of a population map entry
 110  */
 111 typedef u_long          popmap_t;
 112
 113 /*
 114  * The number of bits in a population map entry
 115  */
 116 #define NBPOPMAP        (NBBY * sizeof(popmap_t))
 117
 118 /*
 119  * The number of population map entries in a reservation
 120  */
 121 #define NPOPMAP         howmany(VM_LEVEL_0_NPAGES, NBPOPMAP)
 122 #define NPOPMAP_MAX     howmany(VM_LEVEL_0_NPAGES_MAX, NBPOPMAP)
 123
 124 /*
 125  * Number of elapsed ticks before we update the LRU queue position.  Used
 126  * to reduce contention and churn on the list.
 127  */
 128 #define PARTPOPSLOP     1
 129
 130 /*
 131  * Clear a bit in the population map.
 132  */
 133 static __inline void
 134 popmap_clear(popmap_t popmap[], int i)
 135 {
 136
 137         popmap[i / NBPOPMAP] &= ~(1UL << (i % NBPOPMAP));
 138 }
 139
 140 /*
 141  * Set a bit in the population map.
 142  */
 143 static __inline void
 144 popmap_set(popmap_t popmap[], int i)
 145 {
 146
 147         popmap[i / NBPOPMAP] |= 1UL << (i % NBPOPMAP);
 148 }
 149
 150 /*
 151  * Is a bit in the population map clear?
 152  */
 153 static __inline boolean_t
 154 popmap_is_clear(popmap_t popmap[], int i)
 155 {
 156
 157         return ((popmap[i / NBPOPMAP] & (1UL << (i % NBPOPMAP))) == 0);
 158 }
 159
 160 /*
 161  * Is a bit in the population map set?
 162  */
 163 static __inline boolean_t
 164 popmap_is_set(popmap_t popmap[], int i)
 165 {
 166
 167         return ((popmap[i / NBPOPMAP] & (1UL << (i % NBPOPMAP))) != 0);
 168 }
 169
 170 /*
 171  * The reservation structure
 172  *
 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.
 181  *
 182  * A partially populated reservation can be broken and reclaimed at any time.
 183  *
 184  * c - constant after boot
 185  * d - vm_reserv_domain_lock
 186  * o - vm_reserv_object_lock
 187  * r - vm_reserv_lock
 188  * s - vm_reserv_domain_scan_lock
 189  */
 190 struct vm_reserv {
 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 */
 202 };
 203
 204 TAILQ_HEAD(vm_reserv_queue, vm_reserv);
 205
 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))
 212
 213 /*
 214  * The reservation array
 215  *
 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
 223  * "pages" field.
 224  *
 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.
 228  *
 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.
 233  */
 234 static vm_reserv_t vm_reserv_array;
 235
 236 /*
 237  * The per-domain partially populated reservation queues
 238  *
 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.
 242  *
 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
 245  * lock.
 246  */
 247 struct vm_reserv_domain {
 248         struct mtx              lock;
 249         struct vm_reserv_queue  partpop;        /* (d) */
 250         struct vm_reserv        marker;         /* (d, s) scan marker/lock */
 251 } __aligned(CACHE_LINE_SIZE);
 252
 253 static struct vm_reserv_domain vm_rvd[MAXMEMDOM];
 254
 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))
 260
 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)
 263
 264 static SYSCTL_NODE(_vm, OID_AUTO, reserv, CTLFLAG_RD | CTLFLAG_MPSAFE, 0,
 265     "Reservation Info");
 266
 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");
 270
 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");
 274
 275 static int sysctl_vm_reserv_fullpop(SYSCTL_HANDLER_ARGS);
 276
 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");
 279
 280 static int sysctl_vm_reserv_partpopq(SYSCTL_HANDLER_ARGS);
 281
 282 SYSCTL_OID(_vm_reserv, OID_AUTO, partpopq,
 283     CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, 0,
 284     sysctl_vm_reserv_partpopq, "A",
 285     "Partially populated reservation queues");
 286
 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");
 290
 291 /*
 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.
 294  *
 295  * The "hash" function could be made faster without divide and modulo.
 296  */
 297 #define VM_RESERV_OBJ_LOCK_COUNT        MAXCPU
 298
 299 struct mtx_padalign vm_reserv_object_mtx[VM_RESERV_OBJ_LOCK_COUNT];
 300
 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)))
 309
 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,
 314                             vm_pindex_t pindex);
 315 static void             vm_reserv_populate(vm_reserv_t rv, int index);
 316 static void             vm_reserv_reclaim(vm_reserv_t rv);
 317
 318 /*
 319  * Returns the current number of full reservations.
 320  *
 321  * Since the number of full reservations is computed without acquiring any
 322  * locks, the returned value is inexact.
 323  */
 324 static int
 325 sysctl_vm_reserv_fullpop(SYSCTL_HANDLER_ARGS)
 326 {
 327         vm_paddr_t paddr;
 328         struct vm_phys_seg *seg;
 329         vm_reserv_t rv;
 330         int fullpop, segind;
 331
 332         fullpop = 0;
 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 #ifdef VM_PHYSSEG_SPARSE
 337                 rv = seg->first_reserv + (paddr >> VM_LEVEL_0_SHIFT) -
 338                     (seg->start >> VM_LEVEL_0_SHIFT);
 339 #else
 340                 rv = &vm_reserv_array[paddr >> VM_LEVEL_0_SHIFT];
 341 #endif
 342                 while (paddr + VM_LEVEL_0_SIZE > paddr && paddr +
 343                     VM_LEVEL_0_SIZE <= seg->end) {
 344                         fullpop += rv->popcnt == VM_LEVEL_0_NPAGES;
 345                         paddr += VM_LEVEL_0_SIZE;
 346                         rv++;
 347                 }
 348         }
 349         return (sysctl_handle_int(oidp, &fullpop, 0, req));
 350 }
 351
 352 /*
 353  * Describes the current state of the partially populated reservation queue.
 354  */
 355 static int
 356 sysctl_vm_reserv_partpopq(SYSCTL_HANDLER_ARGS)
 357 {
 358         struct sbuf sbuf;
 359         vm_reserv_t rv;
 360         int counter, error, domain, level, unused_pages;
 361
 362         error = sysctl_wire_old_buffer(req, 0);
 363         if (error != 0)
 364                 return (error);
 365         sbuf_new_for_sysctl(&sbuf, NULL, 128, req);
 366         sbuf_printf(&sbuf, "\nDOMAIN    LEVEL     SIZE  NUMBER\n\n");
 367         for (domain = 0; domain < vm_ndomains; domain++) {
 368                 for (level = -1; level <= VM_NRESERVLEVEL - 2; level++) {
 369                         counter = 0;
 370                         unused_pages = 0;
 371                         vm_reserv_domain_lock(domain);
 372                         TAILQ_FOREACH(rv, &vm_rvd[domain].partpop, partpopq) {
 373                                 if (rv == &vm_rvd[domain].marker)
 374                                         continue;
 375                                 counter++;
 376                                 unused_pages += VM_LEVEL_0_NPAGES - rv->popcnt;
 377                         }
 378                         vm_reserv_domain_unlock(domain);
 379                         sbuf_printf(&sbuf, "%6d, %7d, %6dK, %6d\n",
 380                             domain, level,
 381                             unused_pages * ((int)PAGE_SIZE / 1024), counter);
 382                 }
 383         }
 384         error = sbuf_finish(&sbuf);
 385         sbuf_delete(&sbuf);
 386         return (error);
 387 }
 388
 389 /*
 390  * Remove a reservation from the object's objq.
 391  */
 392 static void
 393 vm_reserv_remove(vm_reserv_t rv)
 394 {
 395         vm_object_t object;
 396
 397         vm_reserv_assert_locked(rv);
 398         CTR5(KTR_VM, "%s: rv %p object %p popcnt %d inpartpop %d",
 399             __FUNCTION__, rv, rv->object, rv->popcnt, rv->inpartpopq);
 400         KASSERT(rv->object != NULL,
 401             ("vm_reserv_remove: reserv %p is free", rv));
 402         KASSERT(!rv->inpartpopq,
 403             ("vm_reserv_remove: reserv %p's inpartpopq is TRUE", rv));
 404         object = rv->object;
 405         vm_reserv_object_lock(object);
 406         LIST_REMOVE(rv, objq);
 407         rv->object = NULL;
 408         vm_reserv_object_unlock(object);
 409 }
 410
 411 /*
 412  * Insert a new reservation into the object's objq.
 413  */
 414 static void
 415 vm_reserv_insert(vm_reserv_t rv, vm_object_t object, vm_pindex_t pindex)
 416 {
 417         int i;
 418
 419         vm_reserv_assert_locked(rv);
 420         CTR6(KTR_VM,
 421             "%s: rv %p(%p) object %p new %p popcnt %d",
 422             __FUNCTION__, rv, rv->pages, rv->object, object,
 423            rv->popcnt);
 424         KASSERT(rv->object == NULL,
 425             ("vm_reserv_insert: reserv %p isn't free", rv));
 426         KASSERT(rv->popcnt == 0,
 427             ("vm_reserv_insert: reserv %p's popcnt is corrupted", rv));
 428         KASSERT(!rv->inpartpopq,
 429             ("vm_reserv_insert: reserv %p's inpartpopq is TRUE", rv));
 430         for (i = 0; i < NPOPMAP; i++)
 431                 KASSERT(rv->popmap[i] == 0,
 432                     ("vm_reserv_insert: reserv %p's popmap is corrupted", rv));
 433         vm_reserv_object_lock(object);
 434         rv->pindex = pindex;
 435         rv->object = object;
 436         rv->lasttick = ticks;
 437         LIST_INSERT_HEAD(&object->rvq, rv, objq);
 438         vm_reserv_object_unlock(object);
 439 }
 440
 441 /*
 442  * Reduces the given reservation's population count.  If the population count
 443  * becomes zero, the reservation is destroyed.  Additionally, moves the
 444  * reservation to the tail of the partially populated reservation queue if the
 445  * population count is non-zero.
 446  */
 447 static void
 448 vm_reserv_depopulate(vm_reserv_t rv, int index)
 449 {
 450         struct vm_domain *vmd;
 451
 452         vm_reserv_assert_locked(rv);
 453         CTR5(KTR_VM, "%s: rv %p object %p popcnt %d inpartpop %d",
 454             __FUNCTION__, rv, rv->object, rv->popcnt, rv->inpartpopq);
 455         KASSERT(rv->object != NULL,
 456             ("vm_reserv_depopulate: reserv %p is free", rv));
 457         KASSERT(popmap_is_set(rv->popmap, index),
 458             ("vm_reserv_depopulate: reserv %p's popmap[%d] is clear", rv,
 459             index));
 460         KASSERT(rv->popcnt > 0,
 461             ("vm_reserv_depopulate: reserv %p's popcnt is corrupted", rv));
 462         KASSERT(rv->domain < vm_ndomains,
 463             ("vm_reserv_depopulate: reserv %p's domain is corrupted %d",
 464             rv, rv->domain));
 465         if (rv->popcnt == VM_LEVEL_0_NPAGES) {
 466                 KASSERT(rv->pages->psind == 1,
 467                     ("vm_reserv_depopulate: reserv %p is already demoted",
 468                     rv));
 469                 rv->pages->psind = 0;
 470         }
 471         popmap_clear(rv->popmap, index);
 472         rv->popcnt--;
 473         if ((unsigned)(ticks - rv->lasttick) >= PARTPOPSLOP ||
 474             rv->popcnt == 0) {
 475                 vm_reserv_domain_lock(rv->domain);
 476                 if (rv->inpartpopq) {
 477                         TAILQ_REMOVE(&vm_rvd[rv->domain].partpop, rv, partpopq);
 478                         rv->inpartpopq = FALSE;
 479                 }
 480                 if (rv->popcnt != 0) {
 481                         rv->inpartpopq = TRUE;
 482                         TAILQ_INSERT_TAIL(&vm_rvd[rv->domain].partpop, rv,
 483                             partpopq);
 484                 }
 485                 vm_reserv_domain_unlock(rv->domain);
 486                 rv->lasttick = ticks;
 487         }
 488         vmd = VM_DOMAIN(rv->domain);
 489         if (rv->popcnt == 0) {
 490                 vm_reserv_remove(rv);
 491                 vm_domain_free_lock(vmd);
 492                 vm_phys_free_pages(rv->pages, VM_LEVEL_0_ORDER);
 493                 vm_domain_free_unlock(vmd);
 494                 counter_u64_add(vm_reserv_freed, 1);
 495         }
 496         vm_domain_freecnt_inc(vmd, 1);
 497 }
 498
 499 /*
 500  * Returns the reservation to which the given page might belong.
 501  */
 502 static __inline vm_reserv_t
 503 vm_reserv_from_page(vm_page_t m)
 504 {
 505 #ifdef VM_PHYSSEG_SPARSE
 506         struct vm_phys_seg *seg;
 507
 508         seg = &vm_phys_segs[m->segind];
 509         return (seg->first_reserv + (VM_PAGE_TO_PHYS(m) >> VM_LEVEL_0_SHIFT) -
 510             (seg->start >> VM_LEVEL_0_SHIFT));
 511 #else
 512         return (&vm_reserv_array[VM_PAGE_TO_PHYS(m) >> VM_LEVEL_0_SHIFT]);
 513 #endif
 514 }
 515
 516 /*
 517  * Returns an existing reservation or NULL and initialized successor pointer.
 518  */
 519 static vm_reserv_t
 520 vm_reserv_from_object(vm_object_t object, vm_pindex_t pindex,
 521     vm_page_t mpred, vm_page_t *msuccp)
 522 {
 523         vm_reserv_t rv;
 524         vm_page_t msucc;
 525
 526         msucc = NULL;
 527         if (mpred != NULL) {
 528                 KASSERT(mpred->object == object,
 529                     ("vm_reserv_from_object: object doesn't contain mpred"));
 530                 KASSERT(mpred->pindex < pindex,
 531                     ("vm_reserv_from_object: mpred doesn't precede pindex"));
 532                 rv = vm_reserv_from_page(mpred);
 533                 if (rv->object == object && vm_reserv_has_pindex(rv, pindex))
 534                         goto found;
 535                 msucc = TAILQ_NEXT(mpred, listq);
 536         } else
 537                 msucc = TAILQ_FIRST(&object->memq);
 538         if (msucc != NULL) {
 539                 KASSERT(msucc->pindex > pindex,
 540                     ("vm_reserv_from_object: msucc doesn't succeed pindex"));
 541                 rv = vm_reserv_from_page(msucc);
 542                 if (rv->object == object && vm_reserv_has_pindex(rv, pindex))
 543                         goto found;
 544         }
 545         rv = NULL;
 546
 547 found:
 548         *msuccp = msucc;
 549
 550         return (rv);
 551 }
 552
 553 /*
 554  * Returns TRUE if the given reservation contains the given page index and
 555  * FALSE otherwise.
 556  */
 557 static __inline boolean_t
 558 vm_reserv_has_pindex(vm_reserv_t rv, vm_pindex_t pindex)
 559 {
 560
 561         return (((pindex - rv->pindex) & ~(VM_LEVEL_0_NPAGES - 1)) == 0);
 562 }
 563
 564 /*
 565  * Increases the given reservation's population count.  Moves the reservation
 566  * to the tail of the partially populated reservation queue.
 567  */
 568 static void
 569 vm_reserv_populate(vm_reserv_t rv, int index)
 570 {
 571
 572         vm_reserv_assert_locked(rv);
 573         CTR5(KTR_VM, "%s: rv %p object %p popcnt %d inpartpop %d",
 574             __FUNCTION__, rv, rv->object, rv->popcnt, rv->inpartpopq);
 575         KASSERT(rv->object != NULL,
 576             ("vm_reserv_populate: reserv %p is free", rv));
 577         KASSERT(popmap_is_clear(rv->popmap, index),
 578             ("vm_reserv_populate: reserv %p's popmap[%d] is set", rv,
 579             index));
 580         KASSERT(rv->popcnt < VM_LEVEL_0_NPAGES,
 581             ("vm_reserv_populate: reserv %p is already full", rv));
 582         KASSERT(rv->pages->psind == 0,
 583             ("vm_reserv_populate: reserv %p is already promoted", rv));
 584         KASSERT(rv->domain < vm_ndomains,
 585             ("vm_reserv_populate: reserv %p's domain is corrupted %d",
 586             rv, rv->domain));
 587         popmap_set(rv->popmap, index);
 588         rv->popcnt++;
 589         if ((unsigned)(ticks - rv->lasttick) < PARTPOPSLOP &&
 590             rv->inpartpopq && rv->popcnt != VM_LEVEL_0_NPAGES)
 591                 return;
 592         rv->lasttick = ticks;
 593         vm_reserv_domain_lock(rv->domain);
 594         if (rv->inpartpopq) {
 595                 TAILQ_REMOVE(&vm_rvd[rv->domain].partpop, rv, partpopq);
 596                 rv->inpartpopq = FALSE;
 597         }
 598         if (rv->popcnt < VM_LEVEL_0_NPAGES) {
 599                 rv->inpartpopq = TRUE;
 600                 TAILQ_INSERT_TAIL(&vm_rvd[rv->domain].partpop, rv, partpopq);
 601         } else {
 602                 KASSERT(rv->pages->psind == 0,
 603                     ("vm_reserv_populate: reserv %p is already promoted",
 604                     rv));
 605                 rv->pages->psind = 1;
 606         }
 607         vm_reserv_domain_unlock(rv->domain);
 608 }
 609
 610 /*
 611  * Allocates a contiguous set of physical pages of the given size "npages"
 612  * from existing or newly created reservations.  All of the physical pages
 613  * must be at or above the given physical address "low" and below the given
 614  * physical address "high".  The given value "alignment" determines the
 615  * alignment of the first physical page in the set.  If the given value
 616  * "boundary" is non-zero, then the set of physical pages cannot cross any
 617  * physical address boundary that is a multiple of that value.  Both
 618  * "alignment" and "boundary" must be a power of two.
 619  *
 620  * The page "mpred" must immediately precede the offset "pindex" within the
 621  * specified object.
 622  *
 623  * The object must be locked.
 624  */
 625 vm_page_t
 626 vm_reserv_alloc_contig(vm_object_t object, vm_pindex_t pindex, int domain,
 627     int req, vm_page_t mpred, u_long npages, vm_paddr_t low, vm_paddr_t high,
 628     u_long alignment, vm_paddr_t boundary)
 629 {
 630         struct vm_domain *vmd;
 631         vm_paddr_t pa, size;
 632         vm_page_t m, m_ret, msucc;
 633         vm_pindex_t first, leftcap, rightcap;
 634         vm_reserv_t rv;
 635         u_long allocpages, maxpages, minpages;
 636         int i, index, n;
 637
 638         VM_OBJECT_ASSERT_WLOCKED(object);
 639         KASSERT(npages != 0, ("vm_reserv_alloc_contig: npages is 0"));
 640
 641         /*
 642          * Is a reservation fundamentally impossible?
 643          */
 644         if (pindex < VM_RESERV_INDEX(object, pindex) ||
 645             pindex + npages > object->size)
 646                 return (NULL);
 647
 648         /*
 649          * All reservations of a particular size have the same alignment.
 650          * Assuming that the first page is allocated from a reservation, the
 651          * least significant bits of its physical address can be determined
 652          * from its offset from the beginning of the reservation and the size
 653          * of the reservation.
 654          *
 655          * Could the specified index within a reservation of the smallest
 656          * possible size satisfy the alignment and boundary requirements?
 657          */
 658         pa = VM_RESERV_INDEX(object, pindex) << PAGE_SHIFT;
 659         if ((pa & (alignment - 1)) != 0)
 660                 return (NULL);
 661         size = npages << PAGE_SHIFT;
 662         if (((pa ^ (pa + size - 1)) & ~(boundary - 1)) != 0)
 663                 return (NULL);
 664
 665         /*
 666          * Look for an existing reservation.
 667          */
 668         rv = vm_reserv_from_object(object, pindex, mpred, &msucc);
 669         if (rv != NULL) {
 670                 KASSERT(object != kernel_object || rv->domain == domain,
 671                     ("vm_reserv_alloc_contig: domain mismatch"));
 672                 index = VM_RESERV_INDEX(object, pindex);
 673                 /* Does the allocation fit within the reservation? */
 674                 if (index + npages > VM_LEVEL_0_NPAGES)
 675                         return (NULL);
 676                 domain = rv->domain;
 677                 vmd = VM_DOMAIN(domain);
 678                 vm_reserv_lock(rv);
 679                 /* Handle reclaim race. */
 680                 if (rv->object != object)
 681                         goto out;
 682                 m = &rv->pages[index];
 683                 pa = VM_PAGE_TO_PHYS(m);
 684                 if (pa < low || pa + size > high ||
 685                     (pa & (alignment - 1)) != 0 ||
 686                     ((pa ^ (pa + size - 1)) & ~(boundary - 1)) != 0)
 687                         goto out;
 688                 /* Handle vm_page_rename(m, new_object, ...). */
 689                 for (i = 0; i < npages; i++)
 690                         if (popmap_is_set(rv->popmap, index + i))
 691                                 goto out;
 692                 if (!vm_domain_allocate(vmd, req, npages))
 693                         goto out;
 694                 for (i = 0; i < npages; i++)
 695                         vm_reserv_populate(rv, index + i);
 696                 vm_reserv_unlock(rv);
 697                 return (m);
 698 out:
 699                 vm_reserv_unlock(rv);
 700                 return (NULL);
 701         }
 702
 703         /*
 704          * Could at least one reservation fit between the first index to the
 705          * left that can be used ("leftcap") and the first index to the right
 706          * that cannot be used ("rightcap")?
 707          *
 708          * We must synchronize with the reserv object lock to protect the
 709          * pindex/object of the resulting reservations against rename while
 710          * we are inspecting.
 711          */
 712         first = pindex - VM_RESERV_INDEX(object, pindex);
 713         minpages = VM_RESERV_INDEX(object, pindex) + npages;
 714         maxpages = roundup2(minpages, VM_LEVEL_0_NPAGES);
 715         allocpages = maxpages;
 716         vm_reserv_object_lock(object);
 717         if (mpred != NULL) {
 718                 if ((rv = vm_reserv_from_page(mpred))->object != object)
 719                         leftcap = mpred->pindex + 1;
 720                 else
 721                         leftcap = rv->pindex + VM_LEVEL_0_NPAGES;
 722                 if (leftcap > first) {
 723                         vm_reserv_object_unlock(object);
 724                         return (NULL);
 725                 }
 726         }
 727         if (msucc != NULL) {
 728                 if ((rv = vm_reserv_from_page(msucc))->object != object)
 729                         rightcap = msucc->pindex;
 730                 else
 731                         rightcap = rv->pindex;
 732                 if (first + maxpages > rightcap) {
 733                         if (maxpages == VM_LEVEL_0_NPAGES) {
 734                                 vm_reserv_object_unlock(object);
 735                                 return (NULL);
 736                         }
 737
 738                         /*
 739                          * At least one reservation will fit between "leftcap"
 740                          * and "rightcap".  However, a reservation for the
 741                          * last of the requested pages will not fit.  Reduce
 742                          * the size of the upcoming allocation accordingly.
 743                          */
 744                         allocpages = minpages;
 745                 }
 746         }
 747         vm_reserv_object_unlock(object);
 748
 749         /*
 750          * Would the last new reservation extend past the end of the object?
 751          *
 752          * If the object is unlikely to grow don't allocate a reservation for
 753          * the tail.
 754          */
 755         if ((object->flags & OBJ_ANON) == 0 &&
 756             first + maxpages > object->size) {
 757                 if (maxpages == VM_LEVEL_0_NPAGES)
 758                         return (NULL);
 759                 allocpages = minpages;
 760         }
 761
 762         /*
 763          * Allocate the physical pages.  The alignment and boundary specified
 764          * for this allocation may be different from the alignment and
 765          * boundary specified for the requested pages.  For instance, the
 766          * specified index may not be the first page within the first new
 767          * reservation.
 768          */
 769         m = NULL;
 770         vmd = VM_DOMAIN(domain);
 771         if (vm_domain_allocate(vmd, req, npages)) {
 772                 vm_domain_free_lock(vmd);
 773                 m = vm_phys_alloc_contig(domain, allocpages, low, high,
 774                     ulmax(alignment, VM_LEVEL_0_SIZE),
 775                     boundary > VM_LEVEL_0_SIZE ? boundary : 0);
 776                 vm_domain_free_unlock(vmd);
 777                 if (m == NULL) {
 778                         vm_domain_freecnt_inc(vmd, npages);
 779                         return (NULL);
 780                 }
 781         } else
 782                 return (NULL);
 783         KASSERT(vm_page_domain(m) == domain,
 784             ("vm_reserv_alloc_contig: Page domain does not match requested."));
 785
 786         /*
 787          * The allocated physical pages always begin at a reservation
 788          * boundary, but they do not always end at a reservation boundary.
 789          * Initialize every reservation that is completely covered by the
 790          * allocated physical pages.
 791          */
 792         m_ret = NULL;
 793         index = VM_RESERV_INDEX(object, pindex);
 794         do {
 795                 rv = vm_reserv_from_page(m);
 796                 KASSERT(rv->pages == m,
 797                     ("vm_reserv_alloc_contig: reserv %p's pages is corrupted",
 798                     rv));
 799                 vm_reserv_lock(rv);
 800                 vm_reserv_insert(rv, object, first);
 801                 n = ulmin(VM_LEVEL_0_NPAGES - index, npages);
 802                 for (i = 0; i < n; i++)
 803                         vm_reserv_populate(rv, index + i);
 804                 npages -= n;
 805                 if (m_ret == NULL) {
 806                         m_ret = &rv->pages[index];
 807                         index = 0;
 808                 }
 809                 vm_reserv_unlock(rv);
 810                 m += VM_LEVEL_0_NPAGES;
 811                 first += VM_LEVEL_0_NPAGES;
 812                 allocpages -= VM_LEVEL_0_NPAGES;
 813         } while (allocpages >= VM_LEVEL_0_NPAGES);
 814         return (m_ret);
 815 }
 816
 817 /*
 818  * Allocate a physical page from an existing or newly created reservation.
 819  *
 820  * The page "mpred" must immediately precede the offset "pindex" within the
 821  * specified object.
 822  *
 823  * The object must be locked.
 824  */
 825 vm_page_t
 826 vm_reserv_alloc_page(vm_object_t object, vm_pindex_t pindex, int domain,
 827     int req, vm_page_t mpred)
 828 {
 829         struct vm_domain *vmd;
 830         vm_page_t m, msucc;
 831         vm_pindex_t first, leftcap, rightcap;
 832         vm_reserv_t rv;
 833         int index;
 834
 835         VM_OBJECT_ASSERT_WLOCKED(object);
 836
 837         /*
 838          * Is a reservation fundamentally impossible?
 839          */
 840         if (pindex < VM_RESERV_INDEX(object, pindex) ||
 841             pindex >= object->size)
 842                 return (NULL);
 843
 844         /*
 845          * Look for an existing reservation.
 846          */
 847         rv = vm_reserv_from_object(object, pindex, mpred, &msucc);
 848         if (rv != NULL) {
 849                 KASSERT(object != kernel_object || rv->domain == domain,
 850                     ("vm_reserv_alloc_page: domain mismatch"));
 851                 domain = rv->domain;
 852                 vmd = VM_DOMAIN(domain);
 853                 index = VM_RESERV_INDEX(object, pindex);
 854                 m = &rv->pages[index];
 855                 vm_reserv_lock(rv);
 856                 /* Handle reclaim race. */
 857                 if (rv->object != object ||
 858                     /* Handle vm_page_rename(m, new_object, ...). */
 859                     popmap_is_set(rv->popmap, index)) {
 860                         m = NULL;
 861                         goto out;
 862                 }
 863                 if (vm_domain_allocate(vmd, req, 1) == 0)
 864                         m = NULL;
 865                 else
 866                         vm_reserv_populate(rv, index);
 867 out:
 868                 vm_reserv_unlock(rv);
 869                 return (m);
 870         }
 871
 872         /*
 873          * Could a reservation fit between the first index to the left that
 874          * can be used and the first index to the right that cannot be used?
 875          *
 876          * We must synchronize with the reserv object lock to protect the
 877          * pindex/object of the resulting reservations against rename while
 878          * we are inspecting.
 879          */
 880         first = pindex - VM_RESERV_INDEX(object, pindex);
 881         vm_reserv_object_lock(object);
 882         if (mpred != NULL) {
 883                 if ((rv = vm_reserv_from_page(mpred))->object != object)
 884                         leftcap = mpred->pindex + 1;
 885                 else
 886                         leftcap = rv->pindex + VM_LEVEL_0_NPAGES;
 887                 if (leftcap > first) {
 888                         vm_reserv_object_unlock(object);
 889                         return (NULL);
 890                 }
 891         }
 892         if (msucc != NULL) {
 893                 if ((rv = vm_reserv_from_page(msucc))->object != object)
 894                         rightcap = msucc->pindex;
 895                 else
 896                         rightcap = rv->pindex;
 897                 if (first + VM_LEVEL_0_NPAGES > rightcap) {
 898                         vm_reserv_object_unlock(object);
 899                         return (NULL);
 900                 }
 901         }
 902         vm_reserv_object_unlock(object);
 903
 904         /*
 905          * Would the last new reservation extend past the end of the object?
 906          *
 907          * If the object is unlikely to grow don't allocate a reservation for
 908          * the tail.
 909          */
 910         if ((object->flags & OBJ_ANON) == 0 &&
 911             first + VM_LEVEL_0_NPAGES > object->size)
 912                 return (NULL);
 913
 914         /*
 915          * Allocate and populate the new reservation.
 916          */
 917         m = NULL;
 918         vmd = VM_DOMAIN(domain);
 919         if (vm_domain_allocate(vmd, req, 1)) {
 920                 vm_domain_free_lock(vmd);
 921                 m = vm_phys_alloc_pages(domain, VM_FREEPOOL_DEFAULT,
 922                     VM_LEVEL_0_ORDER);
 923                 vm_domain_free_unlock(vmd);
 924                 if (m == NULL) {
 925                         vm_domain_freecnt_inc(vmd, 1);
 926                         return (NULL);
 927                 }
 928         } else
 929                 return (NULL);
 930         rv = vm_reserv_from_page(m);
 931         vm_reserv_lock(rv);
 932         KASSERT(rv->pages == m,
 933             ("vm_reserv_alloc_page: reserv %p's pages is corrupted", rv));
 934         vm_reserv_insert(rv, object, first);
 935         index = VM_RESERV_INDEX(object, pindex);
 936         vm_reserv_populate(rv, index);
 937         vm_reserv_unlock(rv);
 938
 939         return (&rv->pages[index]);
 940 }
 941
 942 /*
 943  * Breaks the given reservation.  All free pages in the reservation
 944  * are returned to the physical memory allocator.  The reservation's
 945  * population count and map are reset to their initial state.
 946  *
 947  * The given reservation must not be in the partially populated reservation
 948  * queue.
 949  */
 950 static void
 951 vm_reserv_break(vm_reserv_t rv)
 952 {
 953         u_long changes;
 954         int bitpos, hi, i, lo;
 955
 956         vm_reserv_assert_locked(rv);
 957         CTR5(KTR_VM, "%s: rv %p object %p popcnt %d inpartpop %d",
 958             __FUNCTION__, rv, rv->object, rv->popcnt, rv->inpartpopq);
 959         vm_reserv_remove(rv);
 960         rv->pages->psind = 0;
 961         hi = lo = -1;
 962         for (i = 0; i <= NPOPMAP; i++) {
 963                 /*
 964                  * "changes" is a bitmask that marks where a new sequence of
 965                  * 0s or 1s begins in popmap[i], with last bit in popmap[i-1]
 966                  * considered to be 1 if and only if lo == hi.  The bits of
 967                  * popmap[-1] and popmap[NPOPMAP] are considered all 1s.
 968                  */
 969                 if (i == NPOPMAP)
 970                         changes = lo != hi;
 971                 else {
 972                         changes = rv->popmap[i];
 973                         changes ^= (changes << 1) | (lo == hi);
 974                         rv->popmap[i] = 0;
 975                 }
 976                 while (changes != 0) {
 977                         /*
 978                          * If the next change marked begins a run of 0s, set
 979                          * lo to mark that position.  Otherwise set hi and
 980                          * free pages from lo up to hi.
 981                          */
 982                         bitpos = ffsl(changes) - 1;
 983                         changes ^= 1UL << bitpos;
 984                         if (lo == hi)
 985                                 lo = NBPOPMAP * i + bitpos;
 986                         else {
 987                                 hi = NBPOPMAP * i + bitpos;
 988                                 vm_domain_free_lock(VM_DOMAIN(rv->domain));
 989                                 vm_phys_enqueue_contig(&rv->pages[lo], hi - lo);
 990                                 vm_domain_free_unlock(VM_DOMAIN(rv->domain));
 991                                 lo = hi;
 992                         }
 993                 }
 994         }
 995         rv->popcnt = 0;
 996         counter_u64_add(vm_reserv_broken, 1);
 997 }
 998
 999 /*
1000  * Breaks all reservations belonging to the given object.
1001  */
1002 void
1003 vm_reserv_break_all(vm_object_t object)
1004 {
1005         vm_reserv_t rv;
1006
1007         /*
1008          * This access of object->rvq is unsynchronized so that the
1009          * object rvq lock can nest after the domain_free lock.  We
1010          * must check for races in the results.  However, the object
1011          * lock prevents new additions, so we are guaranteed that when
1012          * it returns NULL the object is properly empty.
1013          */
1014         while ((rv = LIST_FIRST(&object->rvq)) != NULL) {
1015                 vm_reserv_lock(rv);
1016                 /* Reclaim race. */
1017                 if (rv->object != object) {
1018                         vm_reserv_unlock(rv);
1019                         continue;
1020                 }
1021                 vm_reserv_domain_lock(rv->domain);
1022                 if (rv->inpartpopq) {
1023                         TAILQ_REMOVE(&vm_rvd[rv->domain].partpop, rv, partpopq);
1024                         rv->inpartpopq = FALSE;
1025                 }
1026                 vm_reserv_domain_unlock(rv->domain);
1027                 vm_reserv_break(rv);
1028                 vm_reserv_unlock(rv);
1029         }
1030 }
1031
1032 /*
1033  * Frees the given page if it belongs to a reservation.  Returns TRUE if the
1034  * page is freed and FALSE otherwise.
1035  */
1036 boolean_t
1037 vm_reserv_free_page(vm_page_t m)
1038 {
1039         vm_reserv_t rv;
1040         boolean_t ret;
1041
1042         rv = vm_reserv_from_page(m);
1043         if (rv->object == NULL)
1044                 return (FALSE);
1045         vm_reserv_lock(rv);
1046         /* Re-validate after lock. */
1047         if (rv->object != NULL) {
1048                 vm_reserv_depopulate(rv, m - rv->pages);
1049                 ret = TRUE;
1050         } else
1051                 ret = FALSE;
1052         vm_reserv_unlock(rv);
1053
1054         return (ret);
1055 }
1056
1057 /*
1058  * Initializes the reservation management system.  Specifically, initializes
1059  * the reservation array.
1060  *
1061  * Requires that vm_page_array and first_page are initialized!
1062  */
1063 void
1064 vm_reserv_init(void)
1065 {
1066         vm_paddr_t paddr;
1067         struct vm_phys_seg *seg;
1068         struct vm_reserv *rv;
1069         struct vm_reserv_domain *rvd;
1070 #ifdef VM_PHYSSEG_SPARSE
1071         vm_pindex_t used;
1072 #endif
1073         int i, j, segind;
1074
1075         /*
1076          * Initialize the reservation array.  Specifically, initialize the
1077          * "pages" field for every element that has an underlying superpage.
1078          */
1079 #ifdef VM_PHYSSEG_SPARSE
1080         used = 0;
1081 #endif
1082         for (segind = 0; segind < vm_phys_nsegs; segind++) {
1083                 seg = &vm_phys_segs[segind];
1084 #ifdef VM_PHYSSEG_SPARSE
1085                 seg->first_reserv = &vm_reserv_array[used];
1086                 used += howmany(seg->end, VM_LEVEL_0_SIZE) -
1087                     seg->start / VM_LEVEL_0_SIZE;
1088 #else
1089                 seg->first_reserv =
1090                     &vm_reserv_array[seg->start >> VM_LEVEL_0_SHIFT];
1091 #endif
1092                 paddr = roundup2(seg->start, VM_LEVEL_0_SIZE);
1093                 rv = seg->first_reserv + (paddr >> VM_LEVEL_0_SHIFT) -
1094                     (seg->start >> VM_LEVEL_0_SHIFT);
1095                 while (paddr + VM_LEVEL_0_SIZE > paddr && paddr +
1096                     VM_LEVEL_0_SIZE <= seg->end) {
1097                         rv->pages = PHYS_TO_VM_PAGE(paddr);
1098                         rv->domain = seg->domain;
1099                         mtx_init(&rv->lock, "vm reserv", NULL, MTX_DEF);
1100                         paddr += VM_LEVEL_0_SIZE;
1101                         rv++;
1102                 }
1103         }
1104         for (i = 0; i < MAXMEMDOM; i++) {
1105                 rvd = &vm_rvd[i];
1106                 mtx_init(&rvd->lock, "vm reserv domain", NULL, MTX_DEF);
1107                 TAILQ_INIT(&rvd->partpop);
1108                 mtx_init(&rvd->marker.lock, "vm reserv marker", NULL, MTX_DEF);
1109
1110                 /*
1111                  * Fully populated reservations should never be present in the
1112                  * partially populated reservation queues.
1113                  */
1114                 rvd->marker.popcnt = VM_LEVEL_0_NPAGES;
1115                 for (j = 0; j < NBPOPMAP; j++)
1116                         popmap_set(rvd->marker.popmap, j);
1117         }
1118
1119         for (i = 0; i < VM_RESERV_OBJ_LOCK_COUNT; i++)
1120                 mtx_init(&vm_reserv_object_mtx[i], "resv obj lock", NULL,
1121                     MTX_DEF);
1122 }
1123
1124 /*
1125  * Returns true if the given page belongs to a reservation and that page is
1126  * free.  Otherwise, returns false.
1127  */
1128 bool
1129 vm_reserv_is_page_free(vm_page_t m)
1130 {
1131         vm_reserv_t rv;
1132
1133         rv = vm_reserv_from_page(m);
1134         if (rv->object == NULL)
1135                 return (false);
1136         return (popmap_is_clear(rv->popmap, m - rv->pages));
1137 }
1138
1139 /*
1140  * If the given page belongs to a reservation, returns the level of that
1141  * reservation.  Otherwise, returns -1.
1142  */
1143 int
1144 vm_reserv_level(vm_page_t m)
1145 {
1146         vm_reserv_t rv;
1147
1148         rv = vm_reserv_from_page(m);
1149         return (rv->object != NULL ? 0 : -1);
1150 }
1151
1152 /*
1153  * Returns a reservation level if the given page belongs to a fully populated
1154  * reservation and -1 otherwise.
1155  */
1156 int
1157 vm_reserv_level_iffullpop(vm_page_t m)
1158 {
1159         vm_reserv_t rv;
1160
1161         rv = vm_reserv_from_page(m);
1162         return (rv->popcnt == VM_LEVEL_0_NPAGES ? 0 : -1);
1163 }
1164
1165 /*
1166  * Remove a partially populated reservation from the queue.
1167  */
1168 static void
1169 vm_reserv_dequeue(vm_reserv_t rv)
1170 {
1171
1172         vm_reserv_domain_assert_locked(rv->domain);
1173         vm_reserv_assert_locked(rv);
1174         CTR5(KTR_VM, "%s: rv %p object %p popcnt %d inpartpop %d",
1175             __FUNCTION__, rv, rv->object, rv->popcnt, rv->inpartpopq);
1176         KASSERT(rv->inpartpopq,
1177             ("vm_reserv_reclaim: reserv %p's inpartpopq is FALSE", rv));
1178
1179         TAILQ_REMOVE(&vm_rvd[rv->domain].partpop, rv, partpopq);
1180         rv->inpartpopq = FALSE;
1181 }
1182
1183 /*
1184  * Breaks the given partially populated reservation, releasing its free pages
1185  * to the physical memory allocator.
1186  */
1187 static void
1188 vm_reserv_reclaim(vm_reserv_t rv)
1189 {
1190
1191         vm_reserv_assert_locked(rv);
1192         CTR5(KTR_VM, "%s: rv %p object %p popcnt %d inpartpop %d",
1193             __FUNCTION__, rv, rv->object, rv->popcnt, rv->inpartpopq);
1194         if (rv->inpartpopq) {
1195                 vm_reserv_domain_lock(rv->domain);
1196                 vm_reserv_dequeue(rv);
1197                 vm_reserv_domain_unlock(rv->domain);
1198         }
1199         vm_reserv_break(rv);
1200         counter_u64_add(vm_reserv_reclaimed, 1);
1201 }
1202
1203 /*
1204  * Breaks a reservation near the head of the partially populated reservation
1205  * queue, releasing its free pages to the physical memory allocator.  Returns
1206  * TRUE if a reservation is broken and FALSE otherwise.
1207  */
1208 bool
1209 vm_reserv_reclaim_inactive(int domain)
1210 {
1211         vm_reserv_t rv;
1212
1213         vm_reserv_domain_lock(domain);
1214         TAILQ_FOREACH(rv, &vm_rvd[domain].partpop, partpopq) {
1215                 /*
1216                  * A locked reservation is likely being updated or reclaimed,
1217                  * so just skip ahead.
1218                  */
1219                 if (rv != &vm_rvd[domain].marker && vm_reserv_trylock(rv)) {
1220                         vm_reserv_dequeue(rv);
1221                         break;
1222                 }
1223         }
1224         vm_reserv_domain_unlock(domain);
1225         if (rv != NULL) {
1226                 vm_reserv_reclaim(rv);
1227                 vm_reserv_unlock(rv);
1228                 return (true);
1229         }
1230         return (false);
1231 }
1232
1233 /*
1234  * Determine whether this reservation has free pages that satisfy the given
1235  * request for contiguous physical memory.  Start searching from the lower
1236  * bound, defined by low_index.
1237  */
1238 static bool
1239 vm_reserv_test_contig(vm_reserv_t rv, u_long npages, vm_paddr_t low,
1240     vm_paddr_t high, u_long alignment, vm_paddr_t boundary)
1241 {
1242         vm_paddr_t pa, size;
1243         u_long changes;
1244         int bitpos, bits_left, i, hi, lo, n;
1245
1246         vm_reserv_assert_locked(rv);
1247         size = npages << PAGE_SHIFT;
1248         pa = VM_PAGE_TO_PHYS(&rv->pages[0]);
1249         lo = (pa < low) ?
1250             ((low + PAGE_MASK - pa) >> PAGE_SHIFT) : 0;
1251         i = lo / NBPOPMAP;
1252         changes = rv->popmap[i] | ((1UL << (lo % NBPOPMAP)) - 1);
1253         hi = (pa + VM_LEVEL_0_SIZE > high) ?
1254             ((high + PAGE_MASK - pa) >> PAGE_SHIFT) : VM_LEVEL_0_NPAGES;
1255         n = hi / NBPOPMAP;
1256         bits_left = hi % NBPOPMAP;
1257         hi = lo = -1;
1258         for (;;) {
1259                 /*
1260                  * "changes" is a bitmask that marks where a new sequence of
1261                  * 0s or 1s begins in popmap[i], with last bit in popmap[i-1]
1262                  * considered to be 1 if and only if lo == hi.  The bits of
1263                  * popmap[-1] and popmap[NPOPMAP] are considered all 1s.
1264                  */
1265                 changes ^= (changes << 1) | (lo == hi);
1266                 while (changes != 0) {
1267                         /*
1268                          * If the next change marked begins a run of 0s, set
1269                          * lo to mark that position.  Otherwise set hi and
1270                          * look for a satisfactory first page from lo up to hi.
1271                          */
1272                         bitpos = ffsl(changes) - 1;
1273                         changes ^= 1UL << bitpos;
1274                         if (lo == hi) {
1275                                 lo = NBPOPMAP * i + bitpos;
1276                                 continue;
1277                         }
1278                         hi = NBPOPMAP * i + bitpos;
1279                         pa = VM_PAGE_TO_PHYS(&rv->pages[lo]);
1280                         if ((pa & (alignment - 1)) != 0) {
1281                                 /* Skip to next aligned page. */
1282                                 lo += (((pa - 1) | (alignment - 1)) + 1) >>
1283                                     PAGE_SHIFT;
1284                                 if (lo >= VM_LEVEL_0_NPAGES)
1285                                         return (false);
1286                                 pa = VM_PAGE_TO_PHYS(&rv->pages[lo]);
1287                         }
1288                         if (((pa ^ (pa + size - 1)) & ~(boundary - 1)) != 0) {
1289                                 /* Skip to next boundary-matching page. */
1290                                 lo += (((pa - 1) | (boundary - 1)) + 1) >>
1291                                     PAGE_SHIFT;
1292                                 if (lo >= VM_LEVEL_0_NPAGES)
1293                                         return (false);
1294                                 pa = VM_PAGE_TO_PHYS(&rv->pages[lo]);
1295                         }
1296                         if (lo * PAGE_SIZE + size <= hi * PAGE_SIZE)
1297                                 return (true);
1298                         lo = hi;
1299                 }
1300                 if (++i < n)
1301                         changes = rv->popmap[i];
1302                 else if (i == n)
1303                         changes = bits_left == 0 ? -1UL :
1304                             (rv->popmap[n] | (-1UL << bits_left));
1305                 else
1306                         return (false);
1307         }
1308 }
1309
1310 /*
1311  * Searches the partially populated reservation queue for the least recently
1312  * changed reservation with free pages that satisfy the given request for
1313  * contiguous physical memory.  If a satisfactory reservation is found, it is
1314  * broken.  Returns true if a reservation is broken and false otherwise.
1315  */
1316 bool
1317 vm_reserv_reclaim_contig(int domain, u_long npages, vm_paddr_t low,
1318     vm_paddr_t high, u_long alignment, vm_paddr_t boundary)
1319 {
1320         struct vm_reserv_queue *queue;
1321         vm_paddr_t pa, size;
1322         vm_reserv_t marker, rv, rvn;
1323
1324         if (npages > VM_LEVEL_0_NPAGES - 1)
1325                 return (false);
1326         marker = &vm_rvd[domain].marker;
1327         queue = &vm_rvd[domain].partpop;
1328         size = npages << PAGE_SHIFT;
1329
1330         vm_reserv_domain_scan_lock(domain);
1331         vm_reserv_domain_lock(domain);
1332         TAILQ_FOREACH_SAFE(rv, queue, partpopq, rvn) {
1333                 pa = VM_PAGE_TO_PHYS(&rv->pages[0]);
1334                 if (pa + VM_LEVEL_0_SIZE - size < low) {
1335                         /* This entire reservation is too low; go to next. */
1336                         continue;
1337                 }
1338                 if (pa + size > high) {
1339                         /* This entire reservation is too high; go to next. */
1340                         continue;
1341                 }
1342
1343                 if (vm_reserv_trylock(rv) == 0) {
1344                         TAILQ_INSERT_AFTER(queue, rv, marker, partpopq);
1345                         vm_reserv_domain_unlock(domain);
1346                         vm_reserv_lock(rv);
1347                         if (!rv->inpartpopq ||
1348                             TAILQ_NEXT(rv, partpopq) != marker) {
1349                                 vm_reserv_unlock(rv);
1350                                 vm_reserv_domain_lock(domain);
1351                                 rvn = TAILQ_NEXT(marker, partpopq);
1352                                 TAILQ_REMOVE(queue, marker, partpopq);
1353                                 continue;
1354                         }
1355                         vm_reserv_domain_lock(domain);
1356                         TAILQ_REMOVE(queue, marker, partpopq);
1357                 }
1358                 vm_reserv_domain_unlock(domain);
1359                 if (vm_reserv_test_contig(rv, npages, low, high,
1360                     alignment, boundary)) {
1361                         vm_reserv_domain_scan_unlock(domain);
1362                         vm_reserv_reclaim(rv);
1363                         vm_reserv_unlock(rv);
1364                         return (true);
1365                 }
1366                 vm_reserv_unlock(rv);
1367                 vm_reserv_domain_lock(domain);
1368         }
1369         vm_reserv_domain_unlock(domain);
1370         vm_reserv_domain_scan_unlock(domain);
1371         return (false);
1372 }
1373
1374 /*
1375  * Transfers the reservation underlying the given page to a new object.
1376  *
1377  * The object must be locked.
1378  */
1379 void
1380 vm_reserv_rename(vm_page_t m, vm_object_t new_object, vm_object_t old_object,
1381     vm_pindex_t old_object_offset)
1382 {
1383         vm_reserv_t rv;
1384
1385         VM_OBJECT_ASSERT_WLOCKED(new_object);
1386         rv = vm_reserv_from_page(m);
1387         if (rv->object == old_object) {
1388                 vm_reserv_lock(rv);
1389                 CTR6(KTR_VM,
1390                     "%s: rv %p object %p new %p popcnt %d inpartpop %d",
1391                     __FUNCTION__, rv, rv->object, new_object, rv->popcnt,
1392                     rv->inpartpopq);
1393                 if (rv->object == old_object) {
1394                         vm_reserv_object_lock(old_object);
1395                         rv->object = NULL;
1396                         LIST_REMOVE(rv, objq);
1397                         vm_reserv_object_unlock(old_object);
1398                         vm_reserv_object_lock(new_object);
1399                         rv->object = new_object;
1400                         rv->pindex -= old_object_offset;
1401                         LIST_INSERT_HEAD(&new_object->rvq, rv, objq);
1402                         vm_reserv_object_unlock(new_object);
1403                 }
1404                 vm_reserv_unlock(rv);
1405         }
1406 }
1407
1408 /*
1409  * Returns the size (in bytes) of a reservation of the specified level.
1410  */
1411 int
1412 vm_reserv_size(int level)
1413 {
1414
1415         switch (level) {
1416         case 0:
1417                 return (VM_LEVEL_0_SIZE);
1418         case -1:
1419                 return (PAGE_SIZE);
1420         default:
1421                 return (0);
1422         }
1423 }
1424
1425 /*
1426  * Allocates the virtual and physical memory required by the reservation
1427  * management system's data structures, in particular, the reservation array.
1428  */
1429 vm_paddr_t
1430 vm_reserv_startup(vm_offset_t *vaddr, vm_paddr_t end)
1431 {
1432         vm_paddr_t new_end;
1433         vm_pindex_t count;
1434         size_t size;
1435         int i;
1436
1437         count = 0;
1438         for (i = 0; i < vm_phys_nsegs; i++) {
1439 #ifdef VM_PHYSSEG_SPARSE
1440                 count += howmany(vm_phys_segs[i].end, VM_LEVEL_0_SIZE) -
1441                     vm_phys_segs[i].start / VM_LEVEL_0_SIZE;
1442 #else
1443                 count = MAX(count,
1444                     howmany(vm_phys_segs[i].end, VM_LEVEL_0_SIZE));
1445 #endif
1446         }
1447
1448         for (i = 0; phys_avail[i + 1] != 0; i += 2) {
1449 #ifdef VM_PHYSSEG_SPARSE
1450                 count += howmany(phys_avail[i + 1], VM_LEVEL_0_SIZE) -
1451                     phys_avail[i] / VM_LEVEL_0_SIZE;
1452 #else
1453                 count = MAX(count,
1454                     howmany(phys_avail[i + 1], VM_LEVEL_0_SIZE));
1455 #endif
1456         }
1457
1458         /*
1459          * Calculate the size (in bytes) of the reservation array.  Rounding up
1460          * for partial superpages at boundaries, as every small page is mapped
1461          * to an element in the reservation array based on its physical address.
1462          * Thus, the number of elements in the reservation array can be greater
1463          * than the number of superpages.
1464          */
1465         size = count * sizeof(struct vm_reserv);
1466
1467         /*
1468          * Allocate and map the physical memory for the reservation array.  The
1469          * next available virtual address is returned by reference.
1470          */
1471         new_end = end - round_page(size);
1472         vm_reserv_array = (void *)(uintptr_t)pmap_map(vaddr, new_end, end,
1473             VM_PROT_READ | VM_PROT_WRITE);
1474         bzero(vm_reserv_array, size);
1475
1476         /*
1477          * Return the next available physical address.
1478          */
1479         return (new_end);
1480 }
1481
1482 /*
1483  * Returns the superpage containing the given page.
1484  */
1485 vm_page_t
1486 vm_reserv_to_superpage(vm_page_t m)
1487 {
1488         vm_reserv_t rv;
1489
1490         VM_OBJECT_ASSERT_LOCKED(m->object);
1491         rv = vm_reserv_from_page(m);
1492         if (rv->object == m->object && rv->popcnt == VM_LEVEL_0_NPAGES)
1493                 m = rv->pages;
1494         else
1495                 m = NULL;
1496
1497         return (m);
1498 }
1499
1500 #endif  /* VM_NRESERVLEVEL > 0 */