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_phys.h>
  67 #include <vm/vm_pagequeue.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  * r - vm_reserv_lock
 185  * d - vm_reserv_domain_lock
 186  * o - vm_reserv_object_lock
 187  * c - constant after boot
 188  */
 189 struct vm_reserv {
 190         struct mtx      lock;                   /* reservation lock. */
 191         TAILQ_ENTRY(vm_reserv) partpopq;        /* (d, r) per-domain queue. */
 192         LIST_ENTRY(vm_reserv) objq;             /* (o, r) object queue */
 193         vm_object_t     object;                 /* (o, r) containing object */
 194         vm_pindex_t     pindex;                 /* (o, r) offset in object */
 195         vm_page_t       pages;                  /* (c) first page  */
 196         uint16_t        popcnt;                 /* (r) # of pages in use */
 197         uint8_t         domain;                 /* (c) NUMA domain. */
 198         char            inpartpopq;             /* (d, r) */
 199         int             lasttick;               /* (r) last pop update tick. */
 200         popmap_t        popmap[NPOPMAP_MAX];    /* (r) bit vector, used pages */
 201 };
 202
 203 #define vm_reserv_lockptr(rv)           (&(rv)->lock)
 204 #define vm_reserv_assert_locked(rv)                                     \
 205             mtx_assert(vm_reserv_lockptr(rv), MA_OWNED)
 206 #define vm_reserv_lock(rv)              mtx_lock(vm_reserv_lockptr(rv))
 207 #define vm_reserv_trylock(rv)           mtx_trylock(vm_reserv_lockptr(rv))
 208 #define vm_reserv_unlock(rv)            mtx_unlock(vm_reserv_lockptr(rv))
 209
 210 /*
 211  * The reservation array
 212  *
 213  * This array is analoguous in function to vm_page_array.  It differs in the
 214  * respect that it may contain a greater number of useful reservation
 215  * structures than there are (physical) superpages.  These "invalid"
 216  * reservation structures exist to trade-off space for time in the
 217  * implementation of vm_reserv_from_page().  Invalid reservation structures are
 218  * distinguishable from "valid" reservation structures by inspecting the
 219  * reservation's "pages" field.  Invalid reservation structures have a NULL
 220  * "pages" field.
 221  *
 222  * vm_reserv_from_page() maps a small (physical) page to an element of this
 223  * array by computing a physical reservation number from the page's physical
 224  * address.  The physical reservation number is used as the array index.
 225  *
 226  * An "active" reservation is a valid reservation structure that has a non-NULL
 227  * "object" field and a non-zero "popcnt" field.  In other words, every active
 228  * reservation belongs to a particular object.  Moreover, every active
 229  * reservation has an entry in the containing object's list of reservations.
 230  */
 231 static vm_reserv_t vm_reserv_array;
 232
 233 /*
 234  * The per-domain partially populated reservation queues
 235  *
 236  * These queues enable the fast recovery of an unused free small page from a
 237  * partially populated reservation.  The reservation at the head of a queue
 238  * is the least recently changed, partially populated reservation.
 239  *
 240  * Access to this queue is synchronized by the per-domain reservation lock.
 241  */
 242 struct vm_reserv_domain {
 243         struct mtx lock;
 244         TAILQ_HEAD(, vm_reserv) partpop;
 245 } __aligned(CACHE_LINE_SIZE);
 246
 247 static struct vm_reserv_domain vm_rvd[MAXMEMDOM];
 248
 249 #define vm_reserv_domain_lockptr(d)     (&vm_rvd[(d)].lock)
 250 #define vm_reserv_domain_lock(d)        mtx_lock(vm_reserv_domain_lockptr(d))
 251 #define vm_reserv_domain_unlock(d)      mtx_unlock(vm_reserv_domain_lockptr(d))
 252
 253 static SYSCTL_NODE(_vm, OID_AUTO, reserv, CTLFLAG_RD, 0, "Reservation Info");
 254
 255 static counter_u64_t vm_reserv_broken = EARLY_COUNTER;
 256 SYSCTL_COUNTER_U64(_vm_reserv, OID_AUTO, broken, CTLFLAG_RD,
 257     &vm_reserv_broken, "Cumulative number of broken reservations");
 258
 259 static counter_u64_t vm_reserv_freed = EARLY_COUNTER;
 260 SYSCTL_COUNTER_U64(_vm_reserv, OID_AUTO, freed, CTLFLAG_RD,
 261     &vm_reserv_freed, "Cumulative number of freed reservations");
 262
 263 static int sysctl_vm_reserv_fullpop(SYSCTL_HANDLER_ARGS);
 264
 265 SYSCTL_PROC(_vm_reserv, OID_AUTO, fullpop, CTLTYPE_INT | CTLFLAG_RD, NULL, 0,
 266     sysctl_vm_reserv_fullpop, "I", "Current number of full reservations");
 267
 268 static int sysctl_vm_reserv_partpopq(SYSCTL_HANDLER_ARGS);
 269
 270 SYSCTL_OID(_vm_reserv, OID_AUTO, partpopq, CTLTYPE_STRING | CTLFLAG_RD, NULL, 0,
 271     sysctl_vm_reserv_partpopq, "A", "Partially populated reservation queues");
 272
 273 static counter_u64_t vm_reserv_reclaimed = EARLY_COUNTER;
 274 SYSCTL_COUNTER_U64(_vm_reserv, OID_AUTO, reclaimed, CTLFLAG_RD,
 275     &vm_reserv_reclaimed, "Cumulative number of reclaimed reservations");
 276
 277 /*
 278  * The object lock pool is used to synchronize the rvq.  We can not use a
 279  * pool mutex because it is required before malloc works.
 280  *
 281  * The "hash" function could be made faster without divide and modulo.
 282  */
 283 #define VM_RESERV_OBJ_LOCK_COUNT        MAXCPU
 284
 285 struct mtx_padalign vm_reserv_object_mtx[VM_RESERV_OBJ_LOCK_COUNT];
 286
 287 #define vm_reserv_object_lock_idx(object)                       \
 288             (((uintptr_t)object / sizeof(*object)) % VM_RESERV_OBJ_LOCK_COUNT)
 289 #define vm_reserv_object_lock_ptr(object)                       \
 290             &vm_reserv_object_mtx[vm_reserv_object_lock_idx((object))]
 291 #define vm_reserv_object_lock(object)                           \
 292             mtx_lock(vm_reserv_object_lock_ptr((object)))
 293 #define vm_reserv_object_unlock(object)                         \
 294             mtx_unlock(vm_reserv_object_lock_ptr((object)))
 295
 296 static void             vm_reserv_break(vm_reserv_t rv);
 297 static void             vm_reserv_depopulate(vm_reserv_t rv, int index);
 298 static vm_reserv_t      vm_reserv_from_page(vm_page_t m);
 299 static boolean_t        vm_reserv_has_pindex(vm_reserv_t rv,
 300                             vm_pindex_t pindex);
 301 static void             vm_reserv_populate(vm_reserv_t rv, int index);
 302 static void             vm_reserv_reclaim(vm_reserv_t rv);
 303
 304 /*
 305  * Returns the current number of full reservations.
 306  *
 307  * Since the number of full reservations is computed without acquiring any
 308  * locks, the returned value is inexact.
 309  */
 310 static int
 311 sysctl_vm_reserv_fullpop(SYSCTL_HANDLER_ARGS)
 312 {
 313         vm_paddr_t paddr;
 314         struct vm_phys_seg *seg;
 315         vm_reserv_t rv;
 316         int fullpop, segind;
 317
 318         fullpop = 0;
 319         for (segind = 0; segind < vm_phys_nsegs; segind++) {
 320                 seg = &vm_phys_segs[segind];
 321                 paddr = roundup2(seg->start, VM_LEVEL_0_SIZE);
 322                 while (paddr + VM_LEVEL_0_SIZE > paddr && paddr +
 323                     VM_LEVEL_0_SIZE <= seg->end) {
 324                         rv = &vm_reserv_array[paddr >> VM_LEVEL_0_SHIFT];
 325                         fullpop += rv->popcnt == VM_LEVEL_0_NPAGES;
 326                         paddr += VM_LEVEL_0_SIZE;
 327                 }
 328         }
 329         return (sysctl_handle_int(oidp, &fullpop, 0, req));
 330 }
 331
 332 /*
 333  * Describes the current state of the partially populated reservation queue.
 334  */
 335 static int
 336 sysctl_vm_reserv_partpopq(SYSCTL_HANDLER_ARGS)
 337 {
 338         struct sbuf sbuf;
 339         vm_reserv_t rv;
 340         int counter, error, domain, level, unused_pages;
 341
 342         error = sysctl_wire_old_buffer(req, 0);
 343         if (error != 0)
 344                 return (error);
 345         sbuf_new_for_sysctl(&sbuf, NULL, 128, req);
 346         sbuf_printf(&sbuf, "\nDOMAIN    LEVEL     SIZE  NUMBER\n\n");
 347         for (domain = 0; domain < vm_ndomains; domain++) {
 348                 for (level = -1; level <= VM_NRESERVLEVEL - 2; level++) {
 349                         counter = 0;
 350                         unused_pages = 0;
 351                         vm_reserv_domain_lock(domain);
 352                         TAILQ_FOREACH(rv, &vm_rvd[domain].partpop, partpopq) {
 353                                 counter++;
 354                                 unused_pages += VM_LEVEL_0_NPAGES - rv->popcnt;
 355                         }
 356                         vm_reserv_domain_unlock(domain);
 357                         sbuf_printf(&sbuf, "%6d, %7d, %6dK, %6d\n",
 358                             domain, level,
 359                             unused_pages * ((int)PAGE_SIZE / 1024), counter);
 360                 }
 361         }
 362         error = sbuf_finish(&sbuf);
 363         sbuf_delete(&sbuf);
 364         return (error);
 365 }
 366
 367 /*
 368  * Remove a reservation from the object's objq.
 369  */
 370 static void
 371 vm_reserv_remove(vm_reserv_t rv)
 372 {
 373         vm_object_t object;
 374
 375         vm_reserv_assert_locked(rv);
 376         CTR5(KTR_VM, "%s: rv %p object %p popcnt %d inpartpop %d",
 377             __FUNCTION__, rv, rv->object, rv->popcnt, rv->inpartpopq);
 378         KASSERT(rv->object != NULL,
 379             ("vm_reserv_remove: reserv %p is free", rv));
 380         KASSERT(!rv->inpartpopq,
 381             ("vm_reserv_remove: reserv %p's inpartpopq is TRUE", rv));
 382         object = rv->object;
 383         vm_reserv_object_lock(object);
 384         LIST_REMOVE(rv, objq);
 385         rv->object = NULL;
 386         vm_reserv_object_unlock(object);
 387 }
 388
 389 /*
 390  * Insert a new reservation into the object's objq.
 391  */
 392 static void
 393 vm_reserv_insert(vm_reserv_t rv, vm_object_t object, vm_pindex_t pindex)
 394 {
 395         int i;
 396
 397         vm_reserv_assert_locked(rv);
 398         CTR6(KTR_VM,
 399             "%s: rv %p(%p) object %p new %p popcnt %d",
 400             __FUNCTION__, rv, rv->pages, rv->object, object,
 401            rv->popcnt);
 402         KASSERT(rv->object == NULL,
 403             ("vm_reserv_insert: reserv %p isn't free", rv));
 404         KASSERT(rv->popcnt == 0,
 405             ("vm_reserv_insert: reserv %p's popcnt is corrupted", rv));
 406         KASSERT(!rv->inpartpopq,
 407             ("vm_reserv_insert: reserv %p's inpartpopq is TRUE", rv));
 408         for (i = 0; i < NPOPMAP; i++)
 409                 KASSERT(rv->popmap[i] == 0,
 410                     ("vm_reserv_insert: reserv %p's popmap is corrupted", rv));
 411         vm_reserv_object_lock(object);
 412         rv->pindex = pindex;
 413         rv->object = object;
 414         rv->lasttick = ticks;
 415         LIST_INSERT_HEAD(&object->rvq, rv, objq);
 416         vm_reserv_object_unlock(object);
 417 }
 418
 419 /*
 420  * Reduces the given reservation's population count.  If the population count
 421  * becomes zero, the reservation is destroyed.  Additionally, moves the
 422  * reservation to the tail of the partially populated reservation queue if the
 423  * population count is non-zero.
 424  */
 425 static void
 426 vm_reserv_depopulate(vm_reserv_t rv, int index)
 427 {
 428         struct vm_domain *vmd;
 429
 430         vm_reserv_assert_locked(rv);
 431         CTR5(KTR_VM, "%s: rv %p object %p popcnt %d inpartpop %d",
 432             __FUNCTION__, rv, rv->object, rv->popcnt, rv->inpartpopq);
 433         KASSERT(rv->object != NULL,
 434             ("vm_reserv_depopulate: reserv %p is free", rv));
 435         KASSERT(popmap_is_set(rv->popmap, index),
 436             ("vm_reserv_depopulate: reserv %p's popmap[%d] is clear", rv,
 437             index));
 438         KASSERT(rv->popcnt > 0,
 439             ("vm_reserv_depopulate: reserv %p's popcnt is corrupted", rv));
 440         KASSERT(rv->domain < vm_ndomains,
 441             ("vm_reserv_depopulate: reserv %p's domain is corrupted %d",
 442             rv, rv->domain));
 443         if (rv->popcnt == VM_LEVEL_0_NPAGES) {
 444                 KASSERT(rv->pages->psind == 1,
 445                     ("vm_reserv_depopulate: reserv %p is already demoted",
 446                     rv));
 447                 rv->pages->psind = 0;
 448         }
 449         popmap_clear(rv->popmap, index);
 450         rv->popcnt--;
 451         if ((unsigned)(ticks - rv->lasttick) >= PARTPOPSLOP ||
 452             rv->popcnt == 0) {
 453                 vm_reserv_domain_lock(rv->domain);
 454                 if (rv->inpartpopq) {
 455                         TAILQ_REMOVE(&vm_rvd[rv->domain].partpop, rv, partpopq);
 456                         rv->inpartpopq = FALSE;
 457                 }
 458                 if (rv->popcnt != 0) {
 459                         rv->inpartpopq = TRUE;
 460                         TAILQ_INSERT_TAIL(&vm_rvd[rv->domain].partpop, rv,
 461                             partpopq);
 462                 }
 463                 vm_reserv_domain_unlock(rv->domain);
 464                 rv->lasttick = ticks;
 465         }
 466         vmd = VM_DOMAIN(rv->domain);
 467         if (rv->popcnt == 0) {
 468                 vm_reserv_remove(rv);
 469                 vm_domain_free_lock(vmd);
 470                 vm_phys_free_pages(rv->pages, VM_LEVEL_0_ORDER);
 471                 vm_domain_free_unlock(vmd);
 472                 counter_u64_add(vm_reserv_freed, 1);
 473         }
 474         vm_domain_freecnt_inc(vmd, 1);
 475 }
 476
 477 /*
 478  * Returns the reservation to which the given page might belong.
 479  */
 480 static __inline vm_reserv_t
 481 vm_reserv_from_page(vm_page_t m)
 482 {
 483
 484         return (&vm_reserv_array[VM_PAGE_TO_PHYS(m) >> VM_LEVEL_0_SHIFT]);
 485 }
 486
 487 /*
 488  * Returns an existing reservation or NULL and initialized successor pointer.
 489  */
 490 static vm_reserv_t
 491 vm_reserv_from_object(vm_object_t object, vm_pindex_t pindex,
 492     vm_page_t mpred, vm_page_t *msuccp)
 493 {
 494         vm_reserv_t rv;
 495         vm_page_t msucc;
 496
 497         msucc = NULL;
 498         if (mpred != NULL) {
 499                 KASSERT(mpred->object == object,
 500                     ("vm_reserv_from_object: object doesn't contain mpred"));
 501                 KASSERT(mpred->pindex < pindex,
 502                     ("vm_reserv_from_object: mpred doesn't precede pindex"));
 503                 rv = vm_reserv_from_page(mpred);
 504                 if (rv->object == object && vm_reserv_has_pindex(rv, pindex))
 505                         goto found;
 506                 msucc = TAILQ_NEXT(mpred, listq);
 507         } else
 508                 msucc = TAILQ_FIRST(&object->memq);
 509         if (msucc != NULL) {
 510                 KASSERT(msucc->pindex > pindex,
 511                     ("vm_reserv_from_object: msucc doesn't succeed pindex"));
 512                 rv = vm_reserv_from_page(msucc);
 513                 if (rv->object == object && vm_reserv_has_pindex(rv, pindex))
 514                         goto found;
 515         }
 516         rv = NULL;
 517
 518 found:
 519         *msuccp = msucc;
 520
 521         return (rv);
 522 }
 523
 524 /*
 525  * Returns TRUE if the given reservation contains the given page index and
 526  * FALSE otherwise.
 527  */
 528 static __inline boolean_t
 529 vm_reserv_has_pindex(vm_reserv_t rv, vm_pindex_t pindex)
 530 {
 531
 532         return (((pindex - rv->pindex) & ~(VM_LEVEL_0_NPAGES - 1)) == 0);
 533 }
 534
 535 /*
 536  * Increases the given reservation's population count.  Moves the reservation
 537  * to the tail of the partially populated reservation queue.
 538  */
 539 static void
 540 vm_reserv_populate(vm_reserv_t rv, int index)
 541 {
 542
 543         vm_reserv_assert_locked(rv);
 544         CTR5(KTR_VM, "%s: rv %p object %p popcnt %d inpartpop %d",
 545             __FUNCTION__, rv, rv->object, rv->popcnt, rv->inpartpopq);
 546         KASSERT(rv->object != NULL,
 547             ("vm_reserv_populate: reserv %p is free", rv));
 548         KASSERT(popmap_is_clear(rv->popmap, index),
 549             ("vm_reserv_populate: reserv %p's popmap[%d] is set", rv,
 550             index));
 551         KASSERT(rv->popcnt < VM_LEVEL_0_NPAGES,
 552             ("vm_reserv_populate: reserv %p is already full", rv));
 553         KASSERT(rv->pages->psind == 0,
 554             ("vm_reserv_populate: reserv %p is already promoted", rv));
 555         KASSERT(rv->domain < vm_ndomains,
 556             ("vm_reserv_populate: reserv %p's domain is corrupted %d",
 557             rv, rv->domain));
 558         popmap_set(rv->popmap, index);
 559         rv->popcnt++;
 560         if ((unsigned)(ticks - rv->lasttick) < PARTPOPSLOP &&
 561             rv->inpartpopq && rv->popcnt != VM_LEVEL_0_NPAGES)
 562                 return;
 563         rv->lasttick = ticks;
 564         vm_reserv_domain_lock(rv->domain);
 565         if (rv->inpartpopq) {
 566                 TAILQ_REMOVE(&vm_rvd[rv->domain].partpop, rv, partpopq);
 567                 rv->inpartpopq = FALSE;
 568         }
 569         if (rv->popcnt < VM_LEVEL_0_NPAGES) {
 570                 rv->inpartpopq = TRUE;
 571                 TAILQ_INSERT_TAIL(&vm_rvd[rv->domain].partpop, rv, partpopq);
 572         } else {
 573                 KASSERT(rv->pages->psind == 0,
 574                     ("vm_reserv_populate: reserv %p is already promoted",
 575                     rv));
 576                 rv->pages->psind = 1;
 577         }
 578         vm_reserv_domain_unlock(rv->domain);
 579 }
 580
 581 /*
 582  * Allocates a contiguous set of physical pages of the given size "npages"
 583  * from existing or newly created reservations.  All of the physical pages
 584  * must be at or above the given physical address "low" and below the given
 585  * physical address "high".  The given value "alignment" determines the
 586  * alignment of the first physical page in the set.  If the given value
 587  * "boundary" is non-zero, then the set of physical pages cannot cross any
 588  * physical address boundary that is a multiple of that value.  Both
 589  * "alignment" and "boundary" must be a power of two.
 590  *
 591  * The page "mpred" must immediately precede the offset "pindex" within the
 592  * specified object.
 593  *
 594  * The object must be locked.
 595  */
 596 vm_page_t
 597 vm_reserv_alloc_contig(vm_object_t object, vm_pindex_t pindex, int domain,
 598     int req, vm_page_t mpred, u_long npages, vm_paddr_t low, vm_paddr_t high,
 599     u_long alignment, vm_paddr_t boundary)
 600 {
 601         struct vm_domain *vmd;
 602         vm_paddr_t pa, size;
 603         vm_page_t m, m_ret, msucc;
 604         vm_pindex_t first, leftcap, rightcap;
 605         vm_reserv_t rv;
 606         u_long allocpages, maxpages, minpages;
 607         int i, index, n;
 608
 609         VM_OBJECT_ASSERT_WLOCKED(object);
 610         KASSERT(npages != 0, ("vm_reserv_alloc_contig: npages is 0"));
 611
 612         /*
 613          * Is a reservation fundamentally impossible?
 614          */
 615         if (pindex < VM_RESERV_INDEX(object, pindex) ||
 616             pindex + npages > object->size)
 617                 return (NULL);
 618
 619         /*
 620          * All reservations of a particular size have the same alignment.
 621          * Assuming that the first page is allocated from a reservation, the
 622          * least significant bits of its physical address can be determined
 623          * from its offset from the beginning of the reservation and the size
 624          * of the reservation.
 625          *
 626          * Could the specified index within a reservation of the smallest
 627          * possible size satisfy the alignment and boundary requirements?
 628          */
 629         pa = VM_RESERV_INDEX(object, pindex) << PAGE_SHIFT;
 630         if ((pa & (alignment - 1)) != 0)
 631                 return (NULL);
 632         size = npages << PAGE_SHIFT;
 633         if (((pa ^ (pa + size - 1)) & ~(boundary - 1)) != 0)
 634                 return (NULL);
 635
 636         /*
 637          * Look for an existing reservation.
 638          */
 639         rv = vm_reserv_from_object(object, pindex, mpred, &msucc);
 640         if (rv != NULL) {
 641                 KASSERT(object != kernel_object || rv->domain == domain,
 642                     ("vm_reserv_alloc_contig: domain mismatch"));
 643                 index = VM_RESERV_INDEX(object, pindex);
 644                 /* Does the allocation fit within the reservation? */
 645                 if (index + npages > VM_LEVEL_0_NPAGES)
 646                         return (NULL);
 647                 domain = rv->domain;
 648                 vmd = VM_DOMAIN(domain);
 649                 vm_reserv_lock(rv);
 650                 /* Handle reclaim race. */
 651                 if (rv->object != object)
 652                         goto out;
 653                 m = &rv->pages[index];
 654                 pa = VM_PAGE_TO_PHYS(m);
 655                 if (pa < low || pa + size > high ||
 656                     (pa & (alignment - 1)) != 0 ||
 657                     ((pa ^ (pa + size - 1)) & ~(boundary - 1)) != 0)
 658                         goto out;
 659                 /* Handle vm_page_rename(m, new_object, ...). */
 660                 for (i = 0; i < npages; i++)
 661                         if (popmap_is_set(rv->popmap, index + i))
 662                                 goto out;
 663                 if (!vm_domain_allocate(vmd, req, npages))
 664                         goto out;
 665                 for (i = 0; i < npages; i++)
 666                         vm_reserv_populate(rv, index + i);
 667                 vm_reserv_unlock(rv);
 668                 return (m);
 669 out:
 670                 vm_reserv_unlock(rv);
 671                 return (NULL);
 672         }
 673
 674         /*
 675          * Could at least one reservation fit between the first index to the
 676          * left that can be used ("leftcap") and the first index to the right
 677          * that cannot be used ("rightcap")?
 678          *
 679          * We must synchronize with the reserv object lock to protect the
 680          * pindex/object of the resulting reservations against rename while
 681          * we are inspecting.
 682          */
 683         first = pindex - VM_RESERV_INDEX(object, pindex);
 684         minpages = VM_RESERV_INDEX(object, pindex) + npages;
 685         maxpages = roundup2(minpages, VM_LEVEL_0_NPAGES);
 686         allocpages = maxpages;
 687         vm_reserv_object_lock(object);
 688         if (mpred != NULL) {
 689                 if ((rv = vm_reserv_from_page(mpred))->object != object)
 690                         leftcap = mpred->pindex + 1;
 691                 else
 692                         leftcap = rv->pindex + VM_LEVEL_0_NPAGES;
 693                 if (leftcap > first) {
 694                         vm_reserv_object_unlock(object);
 695                         return (NULL);
 696                 }
 697         }
 698         if (msucc != NULL) {
 699                 if ((rv = vm_reserv_from_page(msucc))->object != object)
 700                         rightcap = msucc->pindex;
 701                 else
 702                         rightcap = rv->pindex;
 703                 if (first + maxpages > rightcap) {
 704                         if (maxpages == VM_LEVEL_0_NPAGES) {
 705                                 vm_reserv_object_unlock(object);
 706                                 return (NULL);
 707                         }
 708
 709                         /*
 710                          * At least one reservation will fit between "leftcap"
 711                          * and "rightcap".  However, a reservation for the
 712                          * last of the requested pages will not fit.  Reduce
 713                          * the size of the upcoming allocation accordingly.
 714                          */
 715                         allocpages = minpages;
 716                 }
 717         }
 718         vm_reserv_object_unlock(object);
 719
 720         /*
 721          * Would the last new reservation extend past the end of the object?
 722          *
 723          * If the object is unlikely to grow don't allocate a reservation for
 724          * the tail.
 725          */
 726         if ((object->flags & OBJ_ANON) == 0 &&
 727             first + maxpages > object->size) {
 728                 if (maxpages == VM_LEVEL_0_NPAGES)
 729                         return (NULL);
 730                 allocpages = minpages;
 731         }
 732
 733         /*
 734          * Allocate the physical pages.  The alignment and boundary specified
 735          * for this allocation may be different from the alignment and
 736          * boundary specified for the requested pages.  For instance, the
 737          * specified index may not be the first page within the first new
 738          * reservation.
 739          */
 740         m = NULL;
 741         vmd = VM_DOMAIN(domain);
 742         if (vm_domain_allocate(vmd, req, npages)) {
 743                 vm_domain_free_lock(vmd);
 744                 m = vm_phys_alloc_contig(domain, allocpages, low, high,
 745                     ulmax(alignment, VM_LEVEL_0_SIZE),
 746                     boundary > VM_LEVEL_0_SIZE ? boundary : 0);
 747                 vm_domain_free_unlock(vmd);
 748                 if (m == NULL) {
 749                         vm_domain_freecnt_inc(vmd, npages);
 750                         return (NULL);
 751                 }
 752         } else
 753                 return (NULL);
 754         KASSERT(vm_phys_domain(m) == domain,
 755             ("vm_reserv_alloc_contig: Page domain does not match requested."));
 756
 757         /*
 758          * The allocated physical pages always begin at a reservation
 759          * boundary, but they do not always end at a reservation boundary.
 760          * Initialize every reservation that is completely covered by the
 761          * allocated physical pages.
 762          */
 763         m_ret = NULL;
 764         index = VM_RESERV_INDEX(object, pindex);
 765         do {
 766                 rv = vm_reserv_from_page(m);
 767                 KASSERT(rv->pages == m,
 768                     ("vm_reserv_alloc_contig: reserv %p's pages is corrupted",
 769                     rv));
 770                 vm_reserv_lock(rv);
 771                 vm_reserv_insert(rv, object, first);
 772                 n = ulmin(VM_LEVEL_0_NPAGES - index, npages);
 773                 for (i = 0; i < n; i++)
 774                         vm_reserv_populate(rv, index + i);
 775                 npages -= n;
 776                 if (m_ret == NULL) {
 777                         m_ret = &rv->pages[index];
 778                         index = 0;
 779                 }
 780                 vm_reserv_unlock(rv);
 781                 m += VM_LEVEL_0_NPAGES;
 782                 first += VM_LEVEL_0_NPAGES;
 783                 allocpages -= VM_LEVEL_0_NPAGES;
 784         } while (allocpages >= VM_LEVEL_0_NPAGES);
 785         return (m_ret);
 786 }
 787
 788 /*
 789  * Allocate a physical page from an existing or newly created reservation.
 790  *
 791  * The page "mpred" must immediately precede the offset "pindex" within the
 792  * specified object.
 793  *
 794  * The object must be locked.
 795  */
 796 vm_page_t
 797 vm_reserv_alloc_page(vm_object_t object, vm_pindex_t pindex, int domain,
 798     int req, vm_page_t mpred)
 799 {
 800         struct vm_domain *vmd;
 801         vm_page_t m, msucc;
 802         vm_pindex_t first, leftcap, rightcap;
 803         vm_reserv_t rv;
 804         int index;
 805
 806         VM_OBJECT_ASSERT_WLOCKED(object);
 807
 808         /*
 809          * Is a reservation fundamentally impossible?
 810          */
 811         if (pindex < VM_RESERV_INDEX(object, pindex) ||
 812             pindex >= object->size)
 813                 return (NULL);
 814
 815         /*
 816          * Look for an existing reservation.
 817          */
 818         rv = vm_reserv_from_object(object, pindex, mpred, &msucc);
 819         if (rv != NULL) {
 820                 KASSERT(object != kernel_object || rv->domain == domain,
 821                     ("vm_reserv_alloc_page: domain mismatch"));
 822                 domain = rv->domain;
 823                 vmd = VM_DOMAIN(domain);
 824                 index = VM_RESERV_INDEX(object, pindex);
 825                 m = &rv->pages[index];
 826                 vm_reserv_lock(rv);
 827                 /* Handle reclaim race. */
 828                 if (rv->object != object ||
 829                     /* Handle vm_page_rename(m, new_object, ...). */
 830                     popmap_is_set(rv->popmap, index)) {
 831                         m = NULL;
 832                         goto out;
 833                 }
 834                 if (vm_domain_allocate(vmd, req, 1) == 0)
 835                         m = NULL;
 836                 else
 837                         vm_reserv_populate(rv, index);
 838 out:
 839                 vm_reserv_unlock(rv);
 840                 return (m);
 841         }
 842
 843         /*
 844          * Could a reservation fit between the first index to the left that
 845          * can be used and the first index to the right that cannot be used?
 846          *
 847          * We must synchronize with the reserv object lock to protect the
 848          * pindex/object of the resulting reservations against rename while
 849          * we are inspecting.
 850          */
 851         first = pindex - VM_RESERV_INDEX(object, pindex);
 852         vm_reserv_object_lock(object);
 853         if (mpred != NULL) {
 854                 if ((rv = vm_reserv_from_page(mpred))->object != object)
 855                         leftcap = mpred->pindex + 1;
 856                 else
 857                         leftcap = rv->pindex + VM_LEVEL_0_NPAGES;
 858                 if (leftcap > first) {
 859                         vm_reserv_object_unlock(object);
 860                         return (NULL);
 861                 }
 862         }
 863         if (msucc != NULL) {
 864                 if ((rv = vm_reserv_from_page(msucc))->object != object)
 865                         rightcap = msucc->pindex;
 866                 else
 867                         rightcap = rv->pindex;
 868                 if (first + VM_LEVEL_0_NPAGES > rightcap) {
 869                         vm_reserv_object_unlock(object);
 870                         return (NULL);
 871                 }
 872         }
 873         vm_reserv_object_unlock(object);
 874
 875         /*
 876          * Would the last new reservation extend past the end of the object?
 877          *
 878          * If the object is unlikely to grow don't allocate a reservation for
 879          * the tail.
 880          */
 881         if ((object->flags & OBJ_ANON) == 0 &&
 882             first + VM_LEVEL_0_NPAGES > object->size)
 883                 return (NULL);
 884
 885         /*
 886          * Allocate and populate the new reservation.
 887          */
 888         m = NULL;
 889         vmd = VM_DOMAIN(domain);
 890         if (vm_domain_allocate(vmd, req, 1)) {
 891                 vm_domain_free_lock(vmd);
 892                 m = vm_phys_alloc_pages(domain, VM_FREEPOOL_DEFAULT,
 893                     VM_LEVEL_0_ORDER);
 894                 vm_domain_free_unlock(vmd);
 895                 if (m == NULL) {
 896                         vm_domain_freecnt_inc(vmd, 1);
 897                         return (NULL);
 898                 }
 899         } else
 900                 return (NULL);
 901         rv = vm_reserv_from_page(m);
 902         vm_reserv_lock(rv);
 903         KASSERT(rv->pages == m,
 904             ("vm_reserv_alloc_page: reserv %p's pages is corrupted", rv));
 905         vm_reserv_insert(rv, object, first);
 906         index = VM_RESERV_INDEX(object, pindex);
 907         vm_reserv_populate(rv, index);
 908         vm_reserv_unlock(rv);
 909
 910         return (&rv->pages[index]);
 911 }
 912
 913 /*
 914  * Breaks the given reservation.  All free pages in the reservation
 915  * are returned to the physical memory allocator.  The reservation's
 916  * population count and map are reset to their initial state.
 917  *
 918  * The given reservation must not be in the partially populated reservation
 919  * queue.
 920  */
 921 static void
 922 vm_reserv_break(vm_reserv_t rv)
 923 {
 924         u_long changes;
 925         int bitpos, hi, i, lo;
 926
 927         vm_reserv_assert_locked(rv);
 928         CTR5(KTR_VM, "%s: rv %p object %p popcnt %d inpartpop %d",
 929             __FUNCTION__, rv, rv->object, rv->popcnt, rv->inpartpopq);
 930         vm_reserv_remove(rv);
 931         rv->pages->psind = 0;
 932         hi = lo = -1;
 933         for (i = 0; i <= NPOPMAP; i++) {
 934                 /*
 935                  * "changes" is a bitmask that marks where a new sequence of
 936                  * 0s or 1s begins in popmap[i], with last bit in popmap[i-1]
 937                  * considered to be 1 if and only if lo == hi.  The bits of
 938                  * popmap[-1] and popmap[NPOPMAP] are considered all 1s.
 939                  */
 940                 if (i == NPOPMAP)
 941                         changes = lo != hi;
 942                 else {
 943                         changes = rv->popmap[i];
 944                         changes ^= (changes << 1) | (lo == hi);
 945                         rv->popmap[i] = 0;
 946                 }
 947                 while (changes != 0) {
 948                         /*
 949                          * If the next change marked begins a run of 0s, set
 950                          * lo to mark that position.  Otherwise set hi and
 951                          * free pages from lo up to hi.
 952                          */
 953                         bitpos = ffsl(changes) - 1;
 954                         changes ^= 1UL << bitpos;
 955                         if (lo == hi)
 956                                 lo = NBPOPMAP * i + bitpos;
 957                         else {
 958                                 hi = NBPOPMAP * i + bitpos;
 959                                 vm_domain_free_lock(VM_DOMAIN(rv->domain));
 960                                 vm_phys_enqueue_contig(&rv->pages[lo], hi - lo);
 961                                 vm_domain_free_unlock(VM_DOMAIN(rv->domain));
 962                                 lo = hi;
 963                         }
 964                 }
 965         }
 966         rv->popcnt = 0;
 967         counter_u64_add(vm_reserv_broken, 1);
 968 }
 969
 970 /*
 971  * Breaks all reservations belonging to the given object.
 972  */
 973 void
 974 vm_reserv_break_all(vm_object_t object)
 975 {
 976         vm_reserv_t rv;
 977
 978         /*
 979          * This access of object->rvq is unsynchronized so that the
 980          * object rvq lock can nest after the domain_free lock.  We
 981          * must check for races in the results.  However, the object
 982          * lock prevents new additions, so we are guaranteed that when
 983          * it returns NULL the object is properly empty.
 984          */
 985         while ((rv = LIST_FIRST(&object->rvq)) != NULL) {
 986                 vm_reserv_lock(rv);
 987                 /* Reclaim race. */
 988                 if (rv->object != object) {
 989                         vm_reserv_unlock(rv);
 990                         continue;
 991                 }
 992                 vm_reserv_domain_lock(rv->domain);
 993                 if (rv->inpartpopq) {
 994                         TAILQ_REMOVE(&vm_rvd[rv->domain].partpop, rv, partpopq);
 995                         rv->inpartpopq = FALSE;
 996                 }
 997                 vm_reserv_domain_unlock(rv->domain);
 998                 vm_reserv_break(rv);
 999                 vm_reserv_unlock(rv);
1000         }
1001 }
1002
1003 /*
1004  * Frees the given page if it belongs to a reservation.  Returns TRUE if the
1005  * page is freed and FALSE otherwise.
1006  */
1007 boolean_t
1008 vm_reserv_free_page(vm_page_t m)
1009 {
1010         vm_reserv_t rv;
1011         boolean_t ret;
1012
1013         rv = vm_reserv_from_page(m);
1014         if (rv->object == NULL)
1015                 return (FALSE);
1016         vm_reserv_lock(rv);
1017         /* Re-validate after lock. */
1018         if (rv->object != NULL) {
1019                 vm_reserv_depopulate(rv, m - rv->pages);
1020                 ret = TRUE;
1021         } else
1022                 ret = FALSE;
1023         vm_reserv_unlock(rv);
1024
1025         return (ret);
1026 }
1027
1028 /*
1029  * Initializes the reservation management system.  Specifically, initializes
1030  * the reservation array.
1031  *
1032  * Requires that vm_page_array and first_page are initialized!
1033  */
1034 void
1035 vm_reserv_init(void)
1036 {
1037         vm_paddr_t paddr;
1038         struct vm_phys_seg *seg;
1039         struct vm_reserv *rv;
1040         int i, segind;
1041
1042         /*
1043          * Initialize the reservation array.  Specifically, initialize the
1044          * "pages" field for every element that has an underlying superpage.
1045          */
1046         for (segind = 0; segind < vm_phys_nsegs; segind++) {
1047                 seg = &vm_phys_segs[segind];
1048                 paddr = roundup2(seg->start, VM_LEVEL_0_SIZE);
1049                 while (paddr + VM_LEVEL_0_SIZE > paddr && paddr +
1050                     VM_LEVEL_0_SIZE <= seg->end) {
1051                         rv = &vm_reserv_array[paddr >> VM_LEVEL_0_SHIFT];
1052                         rv->pages = PHYS_TO_VM_PAGE(paddr);
1053                         rv->domain = seg->domain;
1054                         mtx_init(&rv->lock, "vm reserv", NULL, MTX_DEF);
1055                         paddr += VM_LEVEL_0_SIZE;
1056                 }
1057         }
1058         for (i = 0; i < MAXMEMDOM; i++) {
1059                 mtx_init(&vm_rvd[i].lock, "VM reserv domain", NULL, MTX_DEF);
1060                 TAILQ_INIT(&vm_rvd[i].partpop);
1061         }
1062
1063         for (i = 0; i < VM_RESERV_OBJ_LOCK_COUNT; i++)
1064                 mtx_init(&vm_reserv_object_mtx[i], "resv obj lock", NULL,
1065                     MTX_DEF);
1066 }
1067
1068 /*
1069  * Returns true if the given page belongs to a reservation and that page is
1070  * free.  Otherwise, returns false.
1071  */
1072 bool
1073 vm_reserv_is_page_free(vm_page_t m)
1074 {
1075         vm_reserv_t rv;
1076
1077         rv = vm_reserv_from_page(m);
1078         if (rv->object == NULL)
1079                 return (false);
1080         return (popmap_is_clear(rv->popmap, m - rv->pages));
1081 }
1082
1083 /*
1084  * If the given page belongs to a reservation, returns the level of that
1085  * reservation.  Otherwise, returns -1.
1086  */
1087 int
1088 vm_reserv_level(vm_page_t m)
1089 {
1090         vm_reserv_t rv;
1091
1092         rv = vm_reserv_from_page(m);
1093         return (rv->object != NULL ? 0 : -1);
1094 }
1095
1096 /*
1097  * Returns a reservation level if the given page belongs to a fully populated
1098  * reservation and -1 otherwise.
1099  */
1100 int
1101 vm_reserv_level_iffullpop(vm_page_t m)
1102 {
1103         vm_reserv_t rv;
1104
1105         rv = vm_reserv_from_page(m);
1106         return (rv->popcnt == VM_LEVEL_0_NPAGES ? 0 : -1);
1107 }
1108
1109 /*
1110  * Breaks the given partially populated reservation, releasing its free pages
1111  * to the physical memory allocator.
1112  */
1113 static void
1114 vm_reserv_reclaim(vm_reserv_t rv)
1115 {
1116
1117         vm_reserv_assert_locked(rv);
1118         CTR5(KTR_VM, "%s: rv %p object %p popcnt %d inpartpop %d",
1119             __FUNCTION__, rv, rv->object, rv->popcnt, rv->inpartpopq);
1120         vm_reserv_domain_lock(rv->domain);
1121         KASSERT(rv->inpartpopq,
1122             ("vm_reserv_reclaim: reserv %p's inpartpopq is FALSE", rv));
1123         KASSERT(rv->domain < vm_ndomains,
1124             ("vm_reserv_reclaim: reserv %p's domain is corrupted %d",
1125             rv, rv->domain));
1126         TAILQ_REMOVE(&vm_rvd[rv->domain].partpop, rv, partpopq);
1127         rv->inpartpopq = FALSE;
1128         vm_reserv_domain_unlock(rv->domain);
1129         vm_reserv_break(rv);
1130         counter_u64_add(vm_reserv_reclaimed, 1);
1131 }
1132
1133 /*
1134  * Breaks the reservation at the head of the partially populated reservation
1135  * queue, releasing its free pages to the physical memory allocator.  Returns
1136  * TRUE if a reservation is broken and FALSE otherwise.
1137  */
1138 boolean_t
1139 vm_reserv_reclaim_inactive(int domain)
1140 {
1141         vm_reserv_t rv;
1142
1143         while ((rv = TAILQ_FIRST(&vm_rvd[domain].partpop)) != NULL) {
1144                 vm_reserv_lock(rv);
1145                 if (rv != TAILQ_FIRST(&vm_rvd[domain].partpop)) {
1146                         vm_reserv_unlock(rv);
1147                         continue;
1148                 }
1149                 vm_reserv_reclaim(rv);
1150                 vm_reserv_unlock(rv);
1151                 return (TRUE);
1152         }
1153         return (FALSE);
1154 }
1155
1156 /*
1157  * Determine whether this reservation has free pages that satisfy the given
1158  * request for contiguous physical memory.  Start searching from the lower
1159  * bound, defined by low_index.
1160  */
1161 static bool
1162 vm_reserv_test_contig(vm_reserv_t rv, u_long npages, vm_paddr_t low,
1163     vm_paddr_t high, u_long alignment, vm_paddr_t boundary)
1164 {
1165         vm_paddr_t pa, size;
1166         u_long changes;
1167         int bitpos, bits_left, i, hi, lo, n;
1168
1169         vm_reserv_assert_locked(rv);
1170         size = npages << PAGE_SHIFT;
1171         pa = VM_PAGE_TO_PHYS(&rv->pages[0]);
1172         lo = (pa < low) ?
1173             ((low + PAGE_MASK - pa) >> PAGE_SHIFT) : 0;
1174         i = lo / NBPOPMAP;
1175         changes = rv->popmap[i] | ((1UL << (lo % NBPOPMAP)) - 1);
1176         hi = (pa + VM_LEVEL_0_SIZE > high) ?
1177             ((high + PAGE_MASK - pa) >> PAGE_SHIFT) : VM_LEVEL_0_NPAGES;
1178         n = hi / NBPOPMAP;
1179         bits_left = hi % NBPOPMAP;
1180         hi = lo = -1;
1181         for (;;) {
1182                 /*
1183                  * "changes" is a bitmask that marks where a new sequence of
1184                  * 0s or 1s begins in popmap[i], with last bit in popmap[i-1]
1185                  * considered to be 1 if and only if lo == hi.  The bits of
1186                  * popmap[-1] and popmap[NPOPMAP] are considered all 1s.
1187                  */
1188                 changes ^= (changes << 1) | (lo == hi);
1189                 while (changes != 0) {
1190                         /*
1191                          * If the next change marked begins a run of 0s, set
1192                          * lo to mark that position.  Otherwise set hi and
1193                          * look for a satisfactory first page from lo up to hi.
1194                          */
1195                         bitpos = ffsl(changes) - 1;
1196                         changes ^= 1UL << bitpos;
1197                         if (lo == hi) {
1198                                 lo = NBPOPMAP * i + bitpos;
1199                                 continue;
1200                         }
1201                         hi = NBPOPMAP * i + bitpos;
1202                         pa = VM_PAGE_TO_PHYS(&rv->pages[lo]);
1203                         if ((pa & (alignment - 1)) != 0) {
1204                                 /* Skip to next aligned page. */
1205                                 lo += (((pa - 1) | (alignment - 1)) + 1) >>
1206                                     PAGE_SHIFT;
1207                                 if (lo >= VM_LEVEL_0_NPAGES)
1208                                         return (false);
1209                                 pa = VM_PAGE_TO_PHYS(&rv->pages[lo]);
1210                         }
1211                         if (((pa ^ (pa + size - 1)) & ~(boundary - 1)) != 0) {
1212                                 /* Skip to next boundary-matching page. */
1213                                 lo += (((pa - 1) | (boundary - 1)) + 1) >>
1214                                     PAGE_SHIFT;
1215                                 if (lo >= VM_LEVEL_0_NPAGES)
1216                                         return (false);
1217                                 pa = VM_PAGE_TO_PHYS(&rv->pages[lo]);
1218                         }
1219                         if (lo * PAGE_SIZE + size <= hi * PAGE_SIZE)
1220                                 return (true);
1221                         lo = hi;
1222                 }
1223                 if (++i < n)
1224                         changes = rv->popmap[i];
1225                 else if (i == n)
1226                         changes = bits_left == 0 ? -1UL :
1227                             (rv->popmap[n] | (-1UL << bits_left));
1228                 else
1229                         return (false);
1230         }
1231 }
1232
1233 /*
1234  * Searches the partially populated reservation queue for the least recently
1235  * changed reservation with free pages that satisfy the given request for
1236  * contiguous physical memory.  If a satisfactory reservation is found, it is
1237  * broken.  Returns true if a reservation is broken and false otherwise.
1238  */
1239 boolean_t
1240 vm_reserv_reclaim_contig(int domain, u_long npages, vm_paddr_t low,
1241     vm_paddr_t high, u_long alignment, vm_paddr_t boundary)
1242 {
1243         vm_paddr_t pa, size;
1244         vm_reserv_t rv, rvn;
1245
1246         if (npages > VM_LEVEL_0_NPAGES - 1)
1247                 return (false);
1248         size = npages << PAGE_SHIFT;
1249         vm_reserv_domain_lock(domain);
1250 again:
1251         for (rv = TAILQ_FIRST(&vm_rvd[domain].partpop); rv != NULL; rv = rvn) {
1252                 rvn = TAILQ_NEXT(rv, partpopq);
1253                 pa = VM_PAGE_TO_PHYS(&rv->pages[0]);
1254                 if (pa + VM_LEVEL_0_SIZE - size < low) {
1255                         /* This entire reservation is too low; go to next. */
1256                         continue;
1257                 }
1258                 if (pa + size > high) {
1259                         /* This entire reservation is too high; go to next. */
1260                         continue;
1261                 }
1262                 if (vm_reserv_trylock(rv) == 0) {
1263                         vm_reserv_domain_unlock(domain);
1264                         vm_reserv_lock(rv);
1265                         if (!rv->inpartpopq) {
1266                                 vm_reserv_domain_lock(domain);
1267                                 if (!rvn->inpartpopq)
1268                                         goto again;
1269                                 continue;
1270                         }
1271                 } else
1272                         vm_reserv_domain_unlock(domain);
1273                 if (vm_reserv_test_contig(rv, npages, low, high,
1274                     alignment, boundary)) {
1275                         vm_reserv_reclaim(rv);
1276                         vm_reserv_unlock(rv);
1277                         return (true);
1278                 }
1279                 vm_reserv_unlock(rv);
1280                 vm_reserv_domain_lock(domain);
1281                 if (rvn != NULL && !rvn->inpartpopq)
1282                         goto again;
1283         }
1284         vm_reserv_domain_unlock(domain);
1285         return (false);
1286 }
1287
1288 /*
1289  * Transfers the reservation underlying the given page to a new object.
1290  *
1291  * The object must be locked.
1292  */
1293 void
1294 vm_reserv_rename(vm_page_t m, vm_object_t new_object, vm_object_t old_object,
1295     vm_pindex_t old_object_offset)
1296 {
1297         vm_reserv_t rv;
1298
1299         VM_OBJECT_ASSERT_WLOCKED(new_object);
1300         rv = vm_reserv_from_page(m);
1301         if (rv->object == old_object) {
1302                 vm_reserv_lock(rv);
1303                 CTR6(KTR_VM,
1304                     "%s: rv %p object %p new %p popcnt %d inpartpop %d",
1305                     __FUNCTION__, rv, rv->object, new_object, rv->popcnt,
1306                     rv->inpartpopq);
1307                 if (rv->object == old_object) {
1308                         vm_reserv_object_lock(old_object);
1309                         rv->object = NULL;
1310                         LIST_REMOVE(rv, objq);
1311                         vm_reserv_object_unlock(old_object);
1312                         vm_reserv_object_lock(new_object);
1313                         rv->object = new_object;
1314                         rv->pindex -= old_object_offset;
1315                         LIST_INSERT_HEAD(&new_object->rvq, rv, objq);
1316                         vm_reserv_object_unlock(new_object);
1317                 }
1318                 vm_reserv_unlock(rv);
1319         }
1320 }
1321
1322 /*
1323  * Returns the size (in bytes) of a reservation of the specified level.
1324  */
1325 int
1326 vm_reserv_size(int level)
1327 {
1328
1329         switch (level) {
1330         case 0:
1331                 return (VM_LEVEL_0_SIZE);
1332         case -1:
1333                 return (PAGE_SIZE);
1334         default:
1335                 return (0);
1336         }
1337 }
1338
1339 /*
1340  * Allocates the virtual and physical memory required by the reservation
1341  * management system's data structures, in particular, the reservation array.
1342  */
1343 vm_paddr_t
1344 vm_reserv_startup(vm_offset_t *vaddr, vm_paddr_t end)
1345 {
1346         vm_paddr_t new_end, high_water;
1347         size_t size;
1348         int i;
1349
1350         high_water = phys_avail[1];
1351         for (i = 0; i < vm_phys_nsegs; i++) {
1352                 if (vm_phys_segs[i].end > high_water)
1353                         high_water = vm_phys_segs[i].end;
1354         }
1355
1356         /* Skip the first chunk.  It is already accounted for. */
1357         for (i = 2; phys_avail[i + 1] != 0; i += 2) {
1358                 if (phys_avail[i + 1] > high_water)
1359                         high_water = phys_avail[i + 1];
1360         }
1361
1362         /*
1363          * Calculate the size (in bytes) of the reservation array.  Round up
1364          * from "high_water" because every small page is mapped to an element
1365          * in the reservation array based on its physical address.  Thus, the
1366          * number of elements in the reservation array can be greater than the
1367          * number of superpages.
1368          */
1369         size = howmany(high_water, VM_LEVEL_0_SIZE) * sizeof(struct vm_reserv);
1370
1371         /*
1372          * Allocate and map the physical memory for the reservation array.  The
1373          * next available virtual address is returned by reference.
1374          */
1375         new_end = end - round_page(size);
1376         vm_reserv_array = (void *)(uintptr_t)pmap_map(vaddr, new_end, end,
1377             VM_PROT_READ | VM_PROT_WRITE);
1378         bzero(vm_reserv_array, size);
1379
1380         /*
1381          * Return the next available physical address.
1382          */
1383         return (new_end);
1384 }
1385
1386 /*
1387  * Initializes the reservation management system.  Specifically, initializes
1388  * the reservation counters.
1389  */
1390 static void
1391 vm_reserv_counter_init(void *unused)
1392 {
1393
1394         vm_reserv_freed = counter_u64_alloc(M_WAITOK);
1395         vm_reserv_broken = counter_u64_alloc(M_WAITOK);
1396         vm_reserv_reclaimed = counter_u64_alloc(M_WAITOK);
1397 }
1398 SYSINIT(vm_reserv_counter_init, SI_SUB_CPU, SI_ORDER_ANY,
1399     vm_reserv_counter_init, NULL);
1400
1401 /*
1402  * Returns the superpage containing the given page.
1403  */
1404 vm_page_t
1405 vm_reserv_to_superpage(vm_page_t m)
1406 {
1407         vm_reserv_t rv;
1408
1409         VM_OBJECT_ASSERT_LOCKED(m->object);
1410         rv = vm_reserv_from_page(m);
1411         if (rv->object == m->object && rv->popcnt == VM_LEVEL_0_NPAGES)
1412                 m = rv->pages;
1413         else
1414                 m = NULL;
1415
1416         return (m);
1417 }
1418
1419 #endif  /* VM_NRESERVLEVEL > 0 */