1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License (the "License"). 6 * You may not use this file except in compliance with the License. 7 * 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9 * or http://www.opensolaris.org/os/licensing. 10 * See the License for the specific language governing permissions 11 * and limitations under the License. 12 * 13 * When distributing Covered Code, include this CDDL HEADER in each 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15 * If applicable, add the following below this CDDL HEADER, with the 16 * fields enclosed by brackets "[]" replaced with your own identifying 17 * information: Portions Copyright [yyyy] [name of copyright owner] 18 * 19 * CDDL HEADER END 20 */ 21 /* 22 * Copyright 2007 Sun Microsystems, Inc. All rights reserved. 23 * Use is subject to license terms. 24 */ 25 26 /* Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */ 27 /* All Rights Reserved */ 28 29 /* 30 * University Copyright- Copyright (c) 1982, 1986, 1988 31 * The Regents of the University of California 32 * All Rights Reserved 33 * 34 * University Acknowledgment- Portions of this document are derived from 35 * software developed by the University of California, Berkeley, and its 36 * contributors. 37 */ 38 39 #ifndef _VM_PAGE_H 40 #define _VM_PAGE_H 41 42 #pragma ident "@(#)page.h 1.188 07/11/12 SMI" 43 44 #include <vm/seg.h> 45 46 #ifdef __cplusplus 47 extern "C" { 48 #endif 49 50 #if defined(_KERNEL) || defined(_KMEMUSER) 51 52 /* 53 * Shared/Exclusive lock. 54 */ 55 56 /* 57 * Types of page locking supported by page_lock & friends. 58 */ 59 typedef enum { 60 SE_SHARED, 61 SE_EXCL /* exclusive lock (value == -1) */ 62 } se_t; 63 64 /* 65 * For requesting that page_lock reclaim the page from the free list. 66 */ 67 typedef enum { 68 P_RECLAIM, /* reclaim page from free list */ 69 P_NO_RECLAIM /* DON`T reclaim the page */ 70 } reclaim_t; 71 72 /* 73 * Callers of page_try_reclaim_lock and page_lock_es can use this flag 74 * to get SE_EXCL access before reader/writers are given access. 75 */ 76 #define SE_EXCL_WANTED 0x02 77 78 /* 79 * All page_*lock() requests will be denied unless this flag is set in 80 * the 'es' parameter. 81 */ 82 #define SE_RETIRED 0x04 83 84 #endif /* _KERNEL | _KMEMUSER */ 85 86 typedef int selock_t; 87 88 /* 89 * Define VM_STATS to turn on all sorts of statistic gathering about 90 * the VM layer. By default, it is only turned on when DEBUG is 91 * also defined. 92 */ 93 #ifdef DEBUG 94 #define VM_STATS 95 #endif /* DEBUG */ 96 97 #ifdef VM_STATS 98 #define VM_STAT_ADD(stat) (stat)++ 99 #define VM_STAT_COND_ADD(cond, stat) ((void) (!(cond) || (stat)++)) 100 #else 101 #define VM_STAT_ADD(stat) 102 #define VM_STAT_COND_ADD(cond, stat) 103 #endif /* VM_STATS */ 104 105 #ifdef _KERNEL 106 107 /* 108 * Macros to acquire and release the page logical lock. 109 */ 110 #define page_struct_lock(pp) mutex_enter(&page_llock) 111 #define page_struct_unlock(pp) mutex_exit(&page_llock) 112 113 #endif /* _KERNEL */ 114 115 #include <sys/t_lock.h> 116 117 struct as; 118 119 /* 120 * Each physical page has a page structure, which is used to maintain 121 * these pages as a cache. A page can be found via a hashed lookup 122 * based on the [vp, offset]. If a page has an [vp, offset] identity, 123 * then it is entered on a doubly linked circular list off the 124 * vnode using the vpnext/vpprev pointers. If the p_free bit 125 * is on, then the page is also on a doubly linked circular free 126 * list using next/prev pointers. If the "p_selock" and "p_iolock" 127 * are held, then the page is currently being read in (exclusive p_selock) 128 * or written back (shared p_selock). In this case, the next/prev pointers 129 * are used to link the pages together for a consecutive i/o request. If 130 * the page is being brought in from its backing store, then other processes 131 * will wait for the i/o to complete before attaching to the page since it 132 * will have an "exclusive" lock. 133 * 134 * Each page structure has the locks described below along with 135 * the fields they protect: 136 * 137 * p_selock This is a per-page shared/exclusive lock that is 138 * used to implement the logical shared/exclusive 139 * lock for each page. The "shared" lock is normally 140 * used in most cases while the "exclusive" lock is 141 * required to destroy or retain exclusive access to 142 * a page (e.g., while reading in pages). The appropriate 143 * lock is always held whenever there is any reference 144 * to a page structure (e.g., during i/o). 145 * (Note that with the addition of the "writer-lock-wanted" 146 * semantics (via SE_EWANTED), threads must not acquire 147 * multiple reader locks or else a deadly embrace will 148 * occur in the following situation: thread 1 obtains a 149 * reader lock; next thread 2 fails to get a writer lock 150 * but specified SE_EWANTED so it will wait by either 151 * blocking (when using page_lock_es) or spinning while 152 * retrying (when using page_try_reclaim_lock) until the 153 * reader lock is released; then thread 1 attempts to 154 * get another reader lock but is denied due to 155 * SE_EWANTED being set, and now both threads are in a 156 * deadly embrace.) 157 * 158 * p_hash 159 * p_vnode 160 * p_offset 161 * 162 * p_free 163 * p_age 164 * 165 * p_iolock This is a binary semaphore lock that provides 166 * exclusive access to the i/o list links in each 167 * page structure. It is always held while the page 168 * is on an i/o list (i.e., involved in i/o). That is, 169 * even though a page may be only `shared' locked 170 * while it is doing a write, the following fields may 171 * change anyway. Normally, the page must be 172 * `exclusively' locked to change anything in it. 173 * 174 * p_next 175 * p_prev 176 * 177 * The following fields are protected by the global page_llock: 178 * 179 * p_lckcnt 180 * p_cowcnt 181 * 182 * The following lists are protected by the global page_freelock: 183 * 184 * page_cachelist 185 * page_freelist 186 * 187 * The following, for our purposes, are protected by 188 * the global freemem_lock: 189 * 190 * freemem 191 * freemem_wait 192 * freemem_cv 193 * 194 * The following fields are protected by hat layer lock(s). When a page 195 * structure is not mapped and is not associated with a vnode (after a call 196 * to page_hashout() for example) the p_nrm field may be modified with out 197 * holding the hat layer lock: 198 * 199 * p_nrm 200 * p_mapping 201 * p_share 202 * 203 * The following field is file system dependent. How it is used and 204 * the locking strategies applied are up to the individual file system 205 * implementation. 206 * 207 * p_fsdata 208 * 209 * The page structure is used to represent and control the system's 210 * physical pages. There is one instance of the structure for each 211 * page that is not permenately allocated. For example, the pages that 212 * hold the page structures are permanently held by the kernel 213 * and hence do not need page structures to track them. The array 214 * of page structures is allocated early on in the kernel's life and 215 * is based on the amount of available physical memory. 216 * 217 * Each page structure may simultaneously appear on several linked lists. 218 * The lists are: hash list, free or in i/o list, and a vnode's page list. 219 * Each type of list is protected by a different group of mutexes as described 220 * below: 221 * 222 * The hash list is used to quickly find a page when the page's vnode and 223 * offset within the vnode are known. Each page that is hashed is 224 * connected via the `p_hash' field. The anchor for each hash is in the 225 * array `page_hash'. An array of mutexes, `ph_mutex', protects the 226 * lists anchored by page_hash[]. To either search or modify a given hash 227 * list, the appropriate mutex in the ph_mutex array must be held. 228 * 229 * The free list contains pages that are `free to be given away'. For 230 * efficiency reasons, pages on this list are placed in two catagories: 231 * pages that are still associated with a vnode, and pages that are not 232 * associated with a vnode. Free pages always have their `p_free' bit set, 233 * free pages that are still associated with a vnode also have their 234 * `p_age' bit set. Pages on the free list are connected via their 235 * `p_next' and `p_prev' fields. When a page is involved in some sort 236 * of i/o, it is not free and these fields may be used to link associated 237 * pages together. At the moment, the free list is protected by a 238 * single mutex `page_freelock'. The list of free pages still associated 239 * with a vnode is anchored by `page_cachelist' while other free pages 240 * are anchored in architecture dependent ways (to handle page coloring etc.). 241 * 242 * Pages associated with a given vnode appear on a list anchored in the 243 * vnode by the `v_pages' field. They are linked together with 244 * `p_vpnext' and `p_vpprev'. The field `p_offset' contains a page's 245 * offset within the vnode. The pages on this list are not kept in 246 * offset order. These lists, in a manner similar to the hash lists, 247 * are protected by an array of mutexes called `vph_hash'. Before 248 * searching or modifying this chain the appropriate mutex in the 249 * vph_hash[] array must be held. 250 * 251 * Again, each of the lists that a page can appear on is protected by a 252 * mutex. Before reading or writing any of the fields comprising the 253 * list, the appropriate lock must be held. These list locks should only 254 * be held for very short intervals. 255 * 256 * In addition to the list locks, each page structure contains a 257 * shared/exclusive lock that protects various fields within it. 258 * To modify one of these fields, the `p_selock' must be exclusively held. 259 * To read a field with a degree of certainty, the lock must be at least 260 * held shared. 261 * 262 * Removing a page structure from one of the lists requires holding 263 * the appropriate list lock and the page's p_selock. A page may be 264 * prevented from changing identity, being freed, or otherwise modified 265 * by acquiring p_selock shared. 266 * 267 * To avoid deadlocks, a strict locking protocol must be followed. Basically 268 * there are two cases: In the first case, the page structure in question 269 * is known ahead of time (e.g., when the page is to be added or removed 270 * from a list). In the second case, the page structure is not known and 271 * must be found by searching one of the lists. 272 * 273 * When adding or removing a known page to one of the lists, first the 274 * page must be exclusively locked (since at least one of its fields 275 * will be modified), second the lock protecting the list must be acquired, 276 * third the page inserted or deleted, and finally the list lock dropped. 277 * 278 * The more interesting case occures when the particular page structure 279 * is not known ahead of time. For example, when a call is made to 280 * page_lookup(), it is not known if a page with the desired (vnode and 281 * offset pair) identity exists. So the appropriate mutex in ph_mutex is 282 * acquired, the hash list searched, and if the desired page is found 283 * an attempt is made to lock it. The attempt to acquire p_selock must 284 * not block while the hash list lock is held. A deadlock could occure 285 * if some other process was trying to remove the page from the list. 286 * The removing process (following the above protocol) would have exclusively 287 * locked the page, and be spinning waiting to acquire the lock protecting 288 * the hash list. Since the searching process holds the hash list lock 289 * and is waiting to acquire the page lock, a deadlock occurs. 290 * 291 * The proper scheme to follow is: first, lock the appropriate list, 292 * search the list, and if the desired page is found either use 293 * page_trylock() (which will not block) or pass the address of the 294 * list lock to page_lock(). If page_lock() can not acquire the page's 295 * lock, it will drop the list lock before going to sleep. page_lock() 296 * returns a value to indicate if the list lock was dropped allowing the 297 * calling program to react appropriately (i.e., retry the operation). 298 * 299 * If the list lock was dropped before the attempt at locking the page 300 * was made, checks would have to be made to ensure that the page had 301 * not changed identity before its lock was obtained. This is because 302 * the interval between dropping the list lock and acquiring the page 303 * lock is indeterminate. 304 * 305 * In addition, when both a hash list lock (ph_mutex[]) and a vnode list 306 * lock (vph_mutex[]) are needed, the hash list lock must be acquired first. 307 * The routine page_hashin() is a good example of this sequence. 308 * This sequence is ASSERTed by checking that the vph_mutex[] is not held 309 * just before each acquisition of one of the mutexs in ph_mutex[]. 310 * 311 * So, as a quick summary: 312 * 313 * pse_mutex[]'s protect the p_selock and p_cv fields. 314 * 315 * p_selock protects the p_free, p_age, p_vnode, p_offset and p_hash, 316 * 317 * ph_mutex[]'s protect the page_hash[] array and its chains. 318 * 319 * vph_mutex[]'s protect the v_pages field and the vp page chains. 320 * 321 * First lock the page, then the hash chain, then the vnode chain. When 322 * this is not possible `trylocks' must be used. Sleeping while holding 323 * any of these mutexes (p_selock is not a mutex) is not allowed. 324 * 325 * 326 * field reading writing ordering 327 * ====================================================================== 328 * p_vnode p_selock(E,S) p_selock(E) 329 * p_offset 330 * p_free 331 * p_age 332 * ===================================================================== 333 * p_hash p_selock(E,S) p_selock(E) && p_selock, ph_mutex 334 * ph_mutex[] 335 * ===================================================================== 336 * p_vpnext p_selock(E,S) p_selock(E) && p_selock, vph_mutex 337 * p_vpprev vph_mutex[] 338 * ===================================================================== 339 * When the p_free bit is set: 340 * 341 * p_next p_selock(E,S) p_selock(E) && p_selock, 342 * p_prev page_freelock page_freelock 343 * 344 * When the p_free bit is not set: 345 * 346 * p_next p_selock(E,S) p_selock(E) && p_selock, p_iolock 347 * p_prev p_iolock 348 * ===================================================================== 349 * p_selock pse_mutex[] pse_mutex[] can`t acquire any 350 * p_cv other mutexes or 351 * sleep while holding 352 * this lock. 353 * ===================================================================== 354 * p_lckcnt p_selock(E,S) p_selock(E) && 355 * p_cowcnt page_llock 356 * ===================================================================== 357 * p_nrm hat layer lock hat layer lock 358 * p_mapping 359 * p_pagenum 360 * ===================================================================== 361 * 362 * where: 363 * E----> exclusive version of p_selock. 364 * S----> shared version of p_selock. 365 * 366 * 367 * Global data structures and variable: 368 * 369 * field reading writing ordering 370 * ===================================================================== 371 * page_hash[] ph_mutex[] ph_mutex[] can hold this lock 372 * before acquiring 373 * a vph_mutex or 374 * pse_mutex. 375 * ===================================================================== 376 * vp->v_pages vph_mutex[] vph_mutex[] can only acquire 377 * a pse_mutex while 378 * holding this lock. 379 * ===================================================================== 380 * page_cachelist page_freelock page_freelock can't acquire any 381 * page_freelist page_freelock page_freelock 382 * ===================================================================== 383 * freemem freemem_lock freemem_lock can't acquire any 384 * freemem_wait other mutexes while 385 * freemem_cv holding this mutex. 386 * ===================================================================== 387 * 388 * Page relocation, PG_NORELOC and P_NORELOC. 389 * 390 * Pages may be relocated using the page_relocate() interface. Relocation 391 * involves moving the contents and identity of a page to another, free page. 392 * To relocate a page, the SE_EXCL lock must be obtained. The way to prevent 393 * a page from being relocated is to hold the SE_SHARED lock (the SE_EXCL 394 * lock must not be held indefinitely). If the page is going to be held 395 * SE_SHARED indefinitely, then the PG_NORELOC hint should be passed 396 * to page_create_va so that pages that are prevented from being relocated 397 * can be managed differently by the platform specific layer. 398 * 399 * Pages locked in memory using page_pp_lock (p_lckcnt/p_cowcnt != 0) 400 * are guaranteed to be held in memory, but can still be relocated 401 * providing the SE_EXCL lock can be obtained. 402 * 403 * The P_NORELOC bit in the page_t.p_state field is provided for use by 404 * the platform specific code in managing pages when the PG_NORELOC 405 * hint is used. 406 * 407 * Memory delete and page locking. 408 * 409 * The set of all usable pages is managed using the global page list as 410 * implemented by the memseg structure defined below. When memory is added 411 * or deleted this list changes. Additions to this list guarantee that the 412 * list is never corrupt. In order to avoid the necessity of an additional 413 * lock to protect against failed accesses to the memseg being deleted and, 414 * more importantly, the page_ts, the memseg structure is never freed and the 415 * page_t virtual address space is remapped to a page (or pages) of 416 * zeros. If a page_t is manipulated while it is p_selock'd, or if it is 417 * locked indirectly via a hash or freelist lock, it is not possible for 418 * memory delete to collect the page and so that part of the page list is 419 * prevented from being deleted. If the page is referenced outside of one 420 * of these locks, it is possible for the page_t being referenced to be 421 * deleted. Examples of this are page_t pointers returned by 422 * page_numtopp_nolock, page_first and page_next. Providing the page_t 423 * is re-checked after taking the p_selock (for p_vnode != NULL), the 424 * remapping to the zero pages will be detected. 425 * 426 * 427 * Page size (p_szc field) and page locking. 428 * 429 * p_szc field of free pages is changed by free list manager under freelist 430 * locks and is of no concern to the rest of VM subsystem. 431 * 432 * p_szc changes of allocated anonymous (swapfs) can only be done only after 433 * exclusively locking all constituent pages and calling hat_pageunload() on 434 * each of them. To prevent p_szc changes of non free anonymous (swapfs) large 435 * pages it's enough to either lock SHARED any of constituent pages or prevent 436 * hat_pageunload() by holding hat level lock that protects mapping lists (this 437 * method is for hat code only) 438 * 439 * To increase (promote) p_szc of allocated non anonymous file system pages 440 * one has to first lock exclusively all involved constituent pages and call 441 * hat_pageunload() on each of them. To prevent p_szc promote it's enough to 442 * either lock SHARED any of constituent pages that will be needed to make a 443 * large page or prevent hat_pageunload() by holding hat level lock that 444 * protects mapping lists (this method is for hat code only). 445 * 446 * To decrease (demote) p_szc of an allocated non anonymous file system large 447 * page one can either use the same method as used for changeing p_szc of 448 * anonymous large pages or if it's not possible to lock all constituent pages 449 * exclusively a different method can be used. In the second method one only 450 * has to exclusively lock one of constituent pages but then one has to 451 * acquire further locks by calling page_szc_lock() and 452 * hat_page_demote(). hat_page_demote() acquires hat level locks and then 453 * demotes the page. This mechanism relies on the fact that any code that 454 * needs to prevent p_szc of a file system large page from changeing either 455 * locks all constituent large pages at least SHARED or locks some pages at 456 * least SHARED and calls page_szc_lock() or uses hat level page locks. 457 * Demotion using this method is implemented by page_demote_vp_pages(). 458 * Please see comments in front of page_demote_vp_pages(), hat_page_demote() 459 * and page_szc_lock() for more details. 460 * 461 * Lock order: p_selock, page_szc_lock, ph_mutex/vph_mutex/freelist, 462 * hat level locks. 463 */ 464 465 typedef struct page { 466 u_offset_t p_offset; /* offset into vnode for this page */ 467 struct vnode *p_vnode; /* vnode that this page is named by */ 468 selock_t p_selock; /* shared/exclusive lock on the page */ 469 #if defined(_LP64) 470 uint_t p_vpmref; /* vpm ref - index of the vpmap_t */ 471 #endif 472 struct page *p_hash; /* hash by [vnode, offset] */ 473 struct page *p_vpnext; /* next page in vnode list */ 474 struct page *p_vpprev; /* prev page in vnode list */ 475 struct page *p_next; /* next page in free/intrans lists */ 476 struct page *p_prev; /* prev page in free/intrans lists */ 477 ushort_t p_lckcnt; /* number of locks on page data */ 478 ushort_t p_cowcnt; /* number of copy on write lock */ 479 kcondvar_t p_cv; /* page struct's condition var */ 480 kcondvar_t p_io_cv; /* for iolock */ 481 uchar_t p_iolock_state; /* replaces p_iolock */ 482 volatile uchar_t p_szc; /* page size code */ 483 uchar_t p_fsdata; /* file system dependent byte */ 484 uchar_t p_state; /* p_free, p_noreloc */ 485 uchar_t p_nrm; /* non-cache, ref, mod readonly bits */ 486 #if defined(__sparc) 487 uchar_t p_vcolor; /* virtual color */ 488 #else 489 uchar_t p_embed; /* x86 - changes p_mapping & p_index */ 490 #endif 491 uchar_t p_index; /* MPSS mapping info. Not used on x86 */ 492 uchar_t p_toxic; /* page has an unrecoverable error */ 493 void *p_mapping; /* hat specific translation info */ 494 pfn_t p_pagenum; /* physical page number */ 495 496 uint_t p_share; /* number of translations */ 497 #if defined(_LP64) 498 uint_t p_sharepad; /* pad for growing p_share */ 499 #endif 500 uint_t p_slckcnt; /* number of softlocks */ 501 #if defined(__sparc) 502 uint_t p_kpmref; /* number of kpm mapping sharers */ 503 struct kpme *p_kpmelist; /* kpm specific mapping info */ 504 #else 505 /* index of entry in p_map when p_embed is set */ 506 uint_t p_mlentry; 507 #endif 508 #if defined(_LP64) 509 kmutex_t p_ilock; /* protects p_vpmref */ 510 #else 511 uint64_t p_msresv_2; /* page allocation debugging */ 512 #endif 513 } page_t; 514 515 516 typedef page_t devpage_t; 517 #define devpage page 518 519 #define PAGE_LOCK_MAXIMUM \ 520 ((1 << (sizeof (((page_t *)0)->p_lckcnt) * NBBY)) - 1) 521 522 #define PAGE_SLOCK_MAXIMUM UINT_MAX 523 524 /* 525 * Page hash table is a power-of-two in size, externally chained 526 * through the hash field. PAGE_HASHAVELEN is the average length 527 * desired for this chain, from which the size of the page_hash 528 * table is derived at boot time and stored in the kernel variable 529 * page_hashsz. In the hash function it is given by PAGE_HASHSZ. 530 * 531 * PAGE_HASH_FUNC returns an index into the page_hash[] array. This 532 * index is also used to derive the mutex that protects the chain. 533 * 534 * In constructing the hash function, first we dispose of unimportant bits 535 * (page offset from "off" and the low 3 bits of "vp" which are zero for 536 * struct alignment). Then shift and sum the remaining bits a couple times 537 * in order to get as many source bits from the two source values into the 538 * resulting hashed value. Note that this will perform quickly, since the 539 * shifting/summing are fast register to register operations with no additional 540 * memory references). 541 */ 542 #if defined(_LP64) 543 544 #if NCPU < 4 545 #define PH_TABLE_SIZE 128 546 #define VP_SHIFT 7 547 #else 548 #define PH_TABLE_SIZE 1024 549 #define VP_SHIFT 9 550 #endif 551 552 #else /* 32 bits */ 553 554 #if NCPU < 4 555 #define PH_TABLE_SIZE 16 556 #define VP_SHIFT 7 557 #else 558 #define PH_TABLE_SIZE 128 559 #define VP_SHIFT 9 560 #endif 561 562 #endif /* _LP64 */ 563 564 /* 565 * The amount to use for the successive shifts in the hash function below. 566 * The actual value is LOG2(PH_TABLE_SIZE), so that as many bits as 567 * possible will filter thru PAGE_HASH_FUNC() and PAGE_HASH_MUTEX(). 568 */ 569 #define PH_SHIFT_SIZE (7) 570 571 #define PAGE_HASHSZ page_hashsz 572 #define PAGE_HASHAVELEN 4 573 #define PAGE_HASH_FUNC(vp, off) \ 574 ((((uintptr_t)(off) >> PAGESHIFT) + \ 575 ((uintptr_t)(off) >> (PAGESHIFT + PH_SHIFT_SIZE)) + \ 576 ((uintptr_t)(vp) >> 3) + \ 577 ((uintptr_t)(vp) >> (3 + PH_SHIFT_SIZE)) + \ 578 ((uintptr_t)(vp) >> (3 + 2 * PH_SHIFT_SIZE))) & \ 579 (PAGE_HASHSZ - 1)) 580 #ifdef _KERNEL 581 582 /* 583 * The page hash value is re-hashed to an index for the ph_mutex array. 584 * 585 * For 64 bit kernels, the mutex array is padded out to prevent false 586 * sharing of cache sub-blocks (64 bytes) of adjacent mutexes. 587 * 588 * For 32 bit kernels, we don't want to waste kernel address space with 589 * padding, so instead we rely on the hash function to introduce skew of 590 * adjacent vnode/offset indexes (the left shift part of the hash function). 591 * Since sizeof (kmutex_t) is 8, we shift an additional 3 to skew to a different 592 * 64 byte sub-block. 593 */ 594 typedef struct pad_mutex { 595 kmutex_t pad_mutex; 596 #ifdef _LP64 597 char pad_pad[64 - sizeof (kmutex_t)]; 598 #endif 599 } pad_mutex_t; 600 extern pad_mutex_t ph_mutex[]; 601 602 #define PAGE_HASH_MUTEX(x) \ 603 &(ph_mutex[((x) + ((x) >> VP_SHIFT) + ((x) << 3)) & \ 604 (PH_TABLE_SIZE - 1)].pad_mutex) 605 606 /* 607 * Flags used while creating pages. 608 */ 609 #define PG_EXCL 0x0001 610 #define PG_WAIT 0x0002 611 #define PG_PHYSCONTIG 0x0004 /* NOT SUPPORTED */ 612 #define PG_MATCH_COLOR 0x0008 /* SUPPORTED by free list routines */ 613 #define PG_NORELOC 0x0010 /* Non-relocatable alloc hint. */ 614 /* Page must be PP_ISNORELOC */ 615 #define PG_PANIC 0x0020 /* system will panic if alloc fails */ 616 #define PG_PUSHPAGE 0x0040 /* alloc may use reserve */ 617 #define PG_LOCAL 0x0080 /* alloc from given lgrp only */ 618 619 /* 620 * When p_selock has the SE_EWANTED bit set, threads waiting for SE_EXCL 621 * access are given priority over all other waiting threads. 622 */ 623 #define SE_EWANTED 0x40000000 624 #define PAGE_LOCKED(pp) (((pp)->p_selock & ~SE_EWANTED) != 0) 625 #define PAGE_SHARED(pp) (((pp)->p_selock & ~SE_EWANTED) > 0) 626 #define PAGE_EXCL(pp) ((pp)->p_selock < 0) 627 #define PAGE_LOCKED_SE(pp, se) \ 628 ((se) == SE_EXCL ? PAGE_EXCL(pp) : PAGE_SHARED(pp)) 629 630 extern long page_hashsz; 631 extern page_t **page_hash; 632 633 extern kmutex_t page_llock; /* page logical lock mutex */ 634 extern kmutex_t freemem_lock; /* freemem lock */ 635 636 extern pgcnt_t total_pages; /* total pages in the system */ 637 638 /* 639 * Variables controlling locking of physical memory. 640 */ 641 extern pgcnt_t pages_pp_maximum; /* tuning: lock + claim <= max */ 642 extern void init_pages_pp_maximum(void); 643 644 struct lgrp; 645 646 /* page_list_{add,sub} flags */ 647 648 /* which list */ 649 #define PG_FREE_LIST 0x0001 650 #define PG_CACHE_LIST 0x0002 651 652 /* where on list */ 653 #define PG_LIST_TAIL 0x0010 654 #define PG_LIST_HEAD 0x0020 655 656 /* called from */ 657 #define PG_LIST_ISINIT 0x1000 658 659 /* 660 * Page frame operations. 661 */ 662 page_t *page_lookup(struct vnode *, u_offset_t, se_t); 663 page_t *page_lookup_create(struct vnode *, u_offset_t, se_t, page_t *, 664 spgcnt_t *, int); 665 page_t *page_lookup_nowait(struct vnode *, u_offset_t, se_t); 666 page_t *page_find(struct vnode *, u_offset_t); 667 page_t *page_exists(struct vnode *, u_offset_t); 668 int page_exists_physcontig(vnode_t *, u_offset_t, uint_t, page_t *[]); 669 int page_exists_forreal(struct vnode *, u_offset_t, uint_t *); 670 void page_needfree(spgcnt_t); 671 page_t *page_create(struct vnode *, u_offset_t, size_t, uint_t); 672 int page_alloc_pages(struct vnode *, struct seg *, caddr_t, page_t **, 673 page_t **, uint_t, int, int); 674 page_t *page_create_va_large(vnode_t *vp, u_offset_t off, size_t bytes, 675 uint_t flags, struct seg *seg, caddr_t vaddr, void *arg); 676 page_t *page_create_va(struct vnode *, u_offset_t, size_t, uint_t, 677 struct seg *, caddr_t); 678 int page_create_wait(size_t npages, uint_t flags); 679 void page_create_putback(ssize_t npages); 680 void page_free(page_t *, int); 681 void page_free_at_startup(page_t *); 682 void page_free_pages(page_t *); 683 void free_vp_pages(struct vnode *, u_offset_t, size_t); 684 int page_reclaim(page_t *, kmutex_t *); 685 int page_reclaim_pages(page_t *, kmutex_t *, uint_t); 686 void page_destroy(page_t *, int); 687 void page_destroy_pages(page_t *); 688 void page_destroy_free(page_t *); 689 void page_rename(page_t *, struct vnode *, u_offset_t); 690 int page_hashin(page_t *, struct vnode *, u_offset_t, kmutex_t *); 691 void page_hashout(page_t *, kmutex_t *); 692 int page_num_hashin(pfn_t, struct vnode *, u_offset_t); 693 void page_add(page_t **, page_t *); 694 void page_add_common(page_t **, page_t *); 695 void page_sub(page_t **, page_t *); 696 void page_sub_common(page_t **, page_t *); 697 page_t *page_get_freelist(struct vnode *, u_offset_t, struct seg *, 698 caddr_t, size_t, uint_t, struct lgrp *); 699 700 page_t *page_get_cachelist(struct vnode *, u_offset_t, struct seg *, 701 caddr_t, uint_t, struct lgrp *); 702 #if defined(__i386) || defined(__amd64) 703 int page_chk_freelist(uint_t); 704 #endif 705 void page_list_add(page_t *, int); 706 void page_boot_demote(page_t *); 707 void page_promote_size(page_t *, uint_t); 708 void page_list_add_pages(page_t *, int); 709 void page_list_sub(page_t *, int); 710 void page_list_sub_pages(page_t *, uint_t); 711 void page_list_xfer(page_t *, int, int); 712 void page_list_break(page_t **, page_t **, size_t); 713 void page_list_concat(page_t **, page_t **); 714 void page_vpadd(page_t **, page_t *); 715 void page_vpsub(page_t **, page_t *); 716 int page_lock(page_t *, se_t, kmutex_t *, reclaim_t); 717 int page_lock_es(page_t *, se_t, kmutex_t *, reclaim_t, int); 718 void page_lock_clr_exclwanted(page_t *); 719 int page_trylock(page_t *, se_t); 720 int page_try_reclaim_lock(page_t *, se_t, int); 721 int page_tryupgrade(page_t *); 722 void page_downgrade(page_t *); 723 void page_unlock(page_t *); 724 void page_unlock_nocapture(page_t *); 725 void page_lock_delete(page_t *); 726 int page_deleted(page_t *); 727 int page_pp_lock(page_t *, int, int); 728 void page_pp_unlock(page_t *, int, int); 729 int page_resv(pgcnt_t, uint_t); 730 void page_unresv(pgcnt_t); 731 void page_pp_useclaim(page_t *, page_t *, uint_t); 732 int page_addclaim(page_t *); 733 int page_subclaim(page_t *); 734 int page_addclaim_pages(page_t **); 735 int page_subclaim_pages(page_t **); 736 pfn_t page_pptonum(page_t *); 737 page_t *page_numtopp(pfn_t, se_t); 738 page_t *page_numtopp_noreclaim(pfn_t, se_t); 739 page_t *page_numtopp_nolock(pfn_t); 740 page_t *page_numtopp_nowait(pfn_t, se_t); 741 page_t *page_first(); 742 page_t *page_next(page_t *); 743 page_t *page_list_next(page_t *); 744 page_t *page_nextn(page_t *, ulong_t); 745 page_t *page_next_scan_init(void **); 746 page_t *page_next_scan_large(page_t *, ulong_t *, void **); 747 void prefetch_page_r(void *); 748 int ppcopy(page_t *, page_t *); 749 void page_relocate_hash(page_t *, page_t *); 750 void pagezero(page_t *, uint_t, uint_t); 751 void pagescrub(page_t *, uint_t, uint_t); 752 void page_io_lock(page_t *); 753 void page_io_unlock(page_t *); 754 int page_io_trylock(page_t *); 755 int page_iolock_assert(page_t *); 756 void page_iolock_init(page_t *); 757 void page_io_wait(page_t *); 758 int page_io_locked(page_t *); 759 pgcnt_t page_busy(int); 760 void page_lock_init(void); 761 ulong_t page_share_cnt(page_t *); 762 int page_isshared(page_t *); 763 int page_isfree(page_t *); 764 int page_isref(page_t *); 765 int page_ismod(page_t *); 766 int page_release(page_t *, int); 767 void page_retire_init(void); 768 int page_retire(uint64_t, uchar_t); 769 int page_retire_check(uint64_t, uint64_t *); 770 int page_unretire(uint64_t); 771 int page_unretire_pp(page_t *, int); 772 void page_tryretire(page_t *); 773 void page_retire_mdboot(); 774 uint64_t page_retire_pend_count(void); 775 void page_retire_incr_pend_count(void); 776 void page_retire_decr_pend_count(void); 777 void page_clrtoxic(page_t *, uchar_t); 778 void page_settoxic(page_t *, uchar_t); 779 780 int page_mem_avail(pgcnt_t); 781 int page_reclaim_mem(pgcnt_t, pgcnt_t, int); 782 783 void page_set_props(page_t *, uint_t); 784 void page_clr_all_props(page_t *); 785 int page_clear_lck_cow(page_t *, int); 786 787 kmutex_t *page_vnode_mutex(struct vnode *); 788 kmutex_t *page_se_mutex(struct page *); 789 kmutex_t *page_szc_lock(struct page *); 790 int page_szc_lock_assert(struct page *pp); 791 792 /* 793 * Page relocation interfaces. page_relocate() is generic. 794 * page_get_replacement_page() is provided by the PSM. 795 * page_free_replacement_page() is generic. 796 */ 797 int group_page_trylock(page_t *, se_t); 798 void group_page_unlock(page_t *); 799 int page_relocate(page_t **, page_t **, int, int, spgcnt_t *, struct lgrp *); 800 int do_page_relocate(page_t **, page_t **, int, spgcnt_t *, struct lgrp *); 801 page_t *page_get_replacement_page(page_t *, struct lgrp *, uint_t); 802 void page_free_replacement_page(page_t *); 803 int page_relocate_cage(page_t **, page_t **); 804 805 int page_try_demote_pages(page_t *); 806 int page_try_demote_free_pages(page_t *); 807 void page_demote_free_pages(page_t *); 808 809 struct anon_map; 810 811 void page_mark_migrate(struct seg *, caddr_t, size_t, struct anon_map *, 812 ulong_t, vnode_t *, u_offset_t, int); 813 void page_migrate(struct seg *, caddr_t, page_t **, pgcnt_t); 814 815 /* 816 * Tell the PIM we are adding physical memory 817 */ 818 void add_physmem(page_t *, size_t, pfn_t); 819 void add_physmem_cb(page_t *, pfn_t); /* callback for page_t part */ 820 821 /* 822 * hw_page_array[] is configured with hardware supported page sizes by 823 * platform specific code. 824 */ 825 typedef struct { 826 size_t hp_size; 827 uint_t hp_shift; 828 uint_t hp_colors; 829 pgcnt_t hp_pgcnt; /* base pagesize cnt */ 830 } hw_pagesize_t; 831 832 extern hw_pagesize_t hw_page_array[]; 833 extern uint_t page_coloring_shift; 834 extern uint_t page_colors_mask; 835 extern int cpu_page_colors; 836 extern uint_t colorequiv; 837 extern uchar_t colorequivszc[]; 838 839 uint_t page_num_pagesizes(void); 840 uint_t page_num_user_pagesizes(int); 841 size_t page_get_pagesize(uint_t); 842 size_t page_get_user_pagesize(uint_t n); 843 pgcnt_t page_get_pagecnt(uint_t); 844 uint_t page_get_shift(uint_t); 845 int page_szc(size_t); 846 int page_szc_user_filtered(size_t); 847 848 /* page_get_replacement page flags */ 849 #define PGR_SAMESZC 0x1 /* only look for page size same as orig */ 850 #define PGR_NORELOC 0x2 /* allocate a P_NORELOC page */ 851 852 /* 853 * macros for "masked arithmetic" 854 * The purpose is to step through all combinations of a set of bits while 855 * keeping some other bits fixed. Fixed bits need not be contiguous. The 856 * variable bits need not be contiguous either, or even right aligned. The 857 * trick is to set all fixed bits to 1, then increment, then restore the 858 * fixed bits. If incrementing causes a carry from a low bit position, the 859 * carry propagates thru the fixed bits, because they are temporarily set to 1. 860 * v is the value 861 * i is the increment 862 * eq_mask defines the fixed bits 863 * mask limits the size of the result 864 */ 865 #define ADD_MASKED(v, i, eq_mask, mask) \ 866 (((((v) | (eq_mask)) + (i)) & (mask) & ~(eq_mask)) | ((v) & (eq_mask))) 867 868 /* 869 * convenience macro which increments by 1 870 */ 871 #define INC_MASKED(v, eq_mask, mask) ADD_MASKED(v, 1, eq_mask, mask) 872 873 #endif /* _KERNEL */ 874 875 /* 876 * Constants used for the p_iolock_state 877 */ 878 #define PAGE_IO_INUSE 0x1 879 #define PAGE_IO_WANTED 0x2 880 881 /* 882 * Constants used for page_release status 883 */ 884 #define PGREL_NOTREL 0x1 885 #define PGREL_CLEAN 0x2 886 #define PGREL_MOD 0x3 887 888 /* 889 * The p_state field holds what used to be the p_age and p_free 890 * bits. These fields are protected by p_selock (see above). 891 */ 892 #define P_FREE 0x80 /* Page on free list */ 893 #define P_NORELOC 0x40 /* Page is non-relocatable */ 894 #define P_MIGRATE 0x20 /* Migrate page on next touch */ 895 #define P_SWAP 0x10 /* belongs to vnode that is V_ISSWAP */ 896 #define P_BOOTPAGES 0x08 /* member of bootpages list */ 897 898 #define PP_ISFREE(pp) ((pp)->p_state & P_FREE) 899 #define PP_ISAGED(pp) (((pp)->p_state & P_FREE) && \ 900 ((pp)->p_vnode == NULL)) 901 #define PP_ISNORELOC(pp) ((pp)->p_state & P_NORELOC) 902 #define PP_ISKAS(pp) (((pp)->p_vnode == &kvp) || \ 903 ((pp)->p_vnode == &zvp)) 904 #define PP_ISNORELOCKERNEL(pp) (PP_ISNORELOC(pp) && PP_ISKAS(pp)) 905 #define PP_ISMIGRATE(pp) ((pp)->p_state & P_MIGRATE) 906 #define PP_ISSWAP(pp) ((pp)->p_state & P_SWAP) 907 #define PP_ISBOOTPAGES(pp) ((pp)->p_state & P_BOOTPAGES) 908 909 #define PP_SETFREE(pp) ((pp)->p_state = ((pp)->p_state & ~P_MIGRATE) \ 910 | P_FREE) 911 #define PP_SETAGED(pp) ASSERT(PP_ISAGED(pp)) 912 #define PP_SETNORELOC(pp) ((pp)->p_state |= P_NORELOC) 913 #define PP_SETMIGRATE(pp) ((pp)->p_state |= P_MIGRATE) 914 #define PP_SETSWAP(pp) ((pp)->p_state |= P_SWAP) 915 #define PP_SETBOOTPAGES(pp) ((pp)->p_state |= P_BOOTPAGES) 916 917 #define PP_CLRFREE(pp) ((pp)->p_state &= ~P_FREE) 918 #define PP_CLRAGED(pp) ASSERT(!PP_ISAGED(pp)) 919 #define PP_CLRNORELOC(pp) ((pp)->p_state &= ~P_NORELOC) 920 #define PP_CLRMIGRATE(pp) ((pp)->p_state &= ~P_MIGRATE) 921 #define PP_CLRSWAP(pp) ((pp)->p_state &= ~P_SWAP) 922 #define PP_CLRBOOTPAGES(pp) ((pp)->p_state &= ~P_BOOTPAGES) 923 924 /* 925 * Flags for page_t p_toxic, for tracking memory hardware errors. 926 * 927 * These flags are OR'ed into p_toxic with page_settoxic() to track which 928 * error(s) have occurred on a given page. The flags are cleared with 929 * page_clrtoxic(). Both page_settoxic() and page_cleartoxic use atomic 930 * primitives to manipulate the p_toxic field so no other locking is needed. 931 * 932 * When an error occurs on a page, p_toxic is set to record the error. The 933 * error could be a memory error or something else (i.e. a datapath). The Page 934 * Retire mechanism does not try to determine the exact cause of the error; 935 * Page Retire rightly leaves that sort of determination to FMA's Diagnostic 936 * Engine (DE). 937 * 938 * Note that, while p_toxic bits can be set without holding any locks, they 939 * should only be cleared while holding the page exclusively locked. 940 * There is one exception to this, the PR_CAPTURE bit is protected by a mutex 941 * within the page capture logic and thus to set or clear the bit, that mutex 942 * needs to be held. The page does not need to be locked but the page_clrtoxic 943 * function must be used as we need an atomic operation. 944 * Also note that there is what amounts to a hack to prevent recursion with 945 * large pages such that if we are unlocking a page and the PR_CAPTURE bit is 946 * set, we will only try to capture the page if the current threads T_CAPTURING 947 * flag is not set. If the flag is set, the unlock will not try to capture 948 * the page even though the PR_CAPTURE bit is set. 949 * 950 * Pages with PR_UE or PR_FMA flags are retired unconditionally, while pages 951 * with PR_MCE are retired if the system has not retired too many of them. 952 * 953 * A page must be exclusively locked to be retired. Pages can be retired if 954 * they are mapped, modified, or both, as long as they are not marked PR_UE, 955 * since pages with uncorrectable errors cannot be relocated in memory. 956 * Once a page has been successfully retired it is zeroed, attached to the 957 * retired_pages vnode and, finally, PR_RETIRED is set in p_toxic. The other 958 * p_toxic bits are NOT cleared. Pages are not left locked after retiring them 959 * to avoid special case code throughout the kernel; rather, page_*lock() will 960 * fail to lock the page, unless SE_RETIRED is passed as an argument. 961 * 962 * While we have your attention, go take a look at the comments at the 963 * beginning of page_retire.c too. 964 */ 965 #define PR_OK 0x00 /* no problem */ 966 #define PR_MCE 0x01 /* page has seen two or more CEs */ 967 #define PR_UE 0x02 /* page has an unhandled UE */ 968 #define PR_UE_SCRUBBED 0x04 /* page has seen a UE but was cleaned */ 969 #define PR_FMA 0x08 /* A DE wants this page retired */ 970 #define PR_CAPTURE 0x10 /* Generic page capture flag */ 971 #define PR_RESV 0x20 /* Reserved for future use */ 972 #define PR_MSG 0x40 /* message(s) already printed for this page */ 973 #define PR_RETIRED 0x80 /* This page has been retired */ 974 975 #define PR_REASONS (PR_UE | PR_MCE | PR_FMA) 976 #define PR_TOXIC (PR_UE) 977 #define PR_ERRMASK (PR_UE | PR_UE_SCRUBBED | PR_MCE | PR_FMA) 978 #define PR_TOXICFLAGS (0xCF) 979 980 #define PP_RETIRED(pp) ((pp)->p_toxic & PR_RETIRED) 981 #define PP_TOXIC(pp) ((pp)->p_toxic & PR_TOXIC) 982 #define PP_PR_REQ(pp) (((pp)->p_toxic & PR_REASONS) && !PP_RETIRED(pp)) 983 #define PP_PR_NOSHARE(pp) \ 984 ((((pp)->p_toxic & (PR_RETIRED | PR_FMA | PR_UE)) == PR_FMA) && \ 985 !PP_ISKAS(pp)) 986 987 /* 988 * Flags for page_unretire_pp 989 */ 990 #define PR_UNR_FREE 0x1 991 #define PR_UNR_CLEAN 0x2 992 #define PR_UNR_TEMP 0x4 993 994 /* 995 * kpm large page description. 996 * The virtual address range of segkpm is divided into chunks of 997 * kpm_pgsz. Each chunk is controlled by a kpm_page_t. The ushort 998 * is sufficient for 2^^15 * PAGESIZE, so e.g. the maximum kpm_pgsz 999 * for 8K is 256M and 2G for 64K pages. It it kept as small as 1000 * possible to save physical memory space. 1001 * 1002 * There are 2 segkpm mapping windows within in the virtual address 1003 * space when we have to prevent VAC alias conflicts. The so called 1004 * Alias window (mappings are always by PAGESIZE) is controlled by 1005 * kp_refcnta. The regular window is controlled by kp_refcnt for the 1006 * normal operation, which is to use the largest available pagesize. 1007 * When VAC alias conflicts are present within a chunk in the regular 1008 * window the large page mapping is broken up into smaller PAGESIZE 1009 * mappings. kp_refcntc is used to control the pages that are invoked 1010 * in the conflict and kp_refcnts holds the active mappings done 1011 * with the small page size. In non vac conflict mode kp_refcntc is 1012 * also used as "go" indication (-1) for the trap level tsbmiss 1013 * handler. 1014 */ 1015 typedef struct kpm_page { 1016 short kp_refcnt; /* pages mapped large */ 1017 short kp_refcnta; /* pages mapped in Alias window */ 1018 short kp_refcntc; /* TL-tsbmiss flag; #vac alias conflict pages */ 1019 short kp_refcnts; /* vac alias: pages mapped small */ 1020 } kpm_page_t; 1021 1022 /* 1023 * Note: khl_lock offset changes must be reflected in sfmmu_asm.s 1024 */ 1025 typedef struct kpm_hlk { 1026 kmutex_t khl_mutex; /* kpm_page mutex */ 1027 uint_t khl_lock; /* trap level tsbmiss handling */ 1028 } kpm_hlk_t; 1029 1030 /* 1031 * kpm small page description. 1032 * When kpm_pgsz is equal to PAGESIZE a smaller representation is used 1033 * to save memory space. Alias range mappings and regular segkpm 1034 * mappings are done in units of PAGESIZE and can share the mapping 1035 * information and the mappings are always distinguishable by their 1036 * virtual address. Other information neeeded for VAC conflict prevention 1037 * is already available on a per page basis. There are basically 3 states 1038 * a kpm_spage can have: not mapped (0), mapped in Alias range or virtually 1039 * uncached (1) and mapped in the regular segkpm window (-1). The -1 value 1040 * is also used as "go" indication for the segkpm trap level tsbmiss 1041 * handler for small pages (value is kept the same as it is used for large 1042 * mappings). 1043 */ 1044 typedef struct kpm_spage { 1045 char kp_mapped; /* page mapped small */ 1046 } kpm_spage_t; 1047 1048 /* 1049 * Note: kshl_lock offset changes must be reflected in sfmmu_asm.s 1050 */ 1051 typedef struct kpm_shlk { 1052 uint_t kshl_lock; /* trap level tsbmiss handling */ 1053 } kpm_shlk_t; 1054 1055 /* 1056 * Each segment of physical memory is described by a memseg struct. 1057 * Within a segment, memory is considered contiguous. The members 1058 * can be categorized as follows: 1059 * . Platform independent: 1060 * pages, epages, pages_base, pages_end, next, lnext. 1061 * . 64bit only but platform independent: 1062 * kpm_pbase, kpm_nkpmpgs, kpm_pages, kpm_spages. 1063 * . Really platform or mmu specific: 1064 * pagespa, epagespa, nextpa, kpm_pagespa. 1065 * . Mixed: 1066 * msegflags. 1067 */ 1068 struct memseg { 1069 page_t *pages, *epages; /* [from, to] in page array */ 1070 pfn_t pages_base, pages_end; /* [from, to] in page numbers */ 1071 struct memseg *next; /* next segment in list */ 1072 #if defined(__sparc) 1073 struct memseg *lnext; /* next segment in deleted list */ 1074 uint64_t pagespa, epagespa; /* [from, to] page array physical */ 1075 uint64_t nextpa; /* physical next pointer */ 1076 pfn_t kpm_pbase; /* start of kpm range */ 1077 pgcnt_t kpm_nkpmpgs; /* # of kpm_pgsz pages */ 1078 union _mseg_un { 1079 kpm_page_t *kpm_lpgs; /* ptr to kpm_page array */ 1080 kpm_spage_t *kpm_spgs; /* ptr to kpm_spage array */ 1081 } mseg_un; 1082 uint64_t kpm_pagespa; /* physical ptr to kpm (s)pages array */ 1083 uint_t msegflags; /* memseg flags */ 1084 #endif /* __sparc */ 1085 }; 1086 1087 /* memseg union aliases */ 1088 #define kpm_pages mseg_un.kpm_lpgs 1089 #define kpm_spages mseg_un.kpm_spgs 1090 1091 /* msegflags */ 1092 #define MEMSEG_DYNAMIC 0x1 /* DR: memory was added dynamically */ 1093 1094 /* memseg support macros */ 1095 #define MSEG_NPAGES(SEG) ((SEG)->pages_end - (SEG)->pages_base) 1096 1097 /* memseg hash */