17c478bd9Sstevel@tonic-gate /* 27c478bd9Sstevel@tonic-gate * CDDL HEADER START 37c478bd9Sstevel@tonic-gate * 47c478bd9Sstevel@tonic-gate * The contents of this file are subject to the terms of the 58bc68872Selowe * Common Development and Distribution License (the "License"). 68bc68872Selowe * You may not use this file except in compliance with the License. 77c478bd9Sstevel@tonic-gate * 87c478bd9Sstevel@tonic-gate * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 97c478bd9Sstevel@tonic-gate * or http://www.opensolaris.org/os/licensing. 107c478bd9Sstevel@tonic-gate * See the License for the specific language governing permissions 117c478bd9Sstevel@tonic-gate * and limitations under the License. 127c478bd9Sstevel@tonic-gate * 137c478bd9Sstevel@tonic-gate * When distributing Covered Code, include this CDDL HEADER in each 147c478bd9Sstevel@tonic-gate * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 157c478bd9Sstevel@tonic-gate * If applicable, add the following below this CDDL HEADER, with the 167c478bd9Sstevel@tonic-gate * fields enclosed by brackets "[]" replaced with your own identifying 177c478bd9Sstevel@tonic-gate * information: Portions Copyright [yyyy] [name of copyright owner] 187c478bd9Sstevel@tonic-gate * 197c478bd9Sstevel@tonic-gate * CDDL HEADER END 207c478bd9Sstevel@tonic-gate */ 217c478bd9Sstevel@tonic-gate /* 22ae115bc7Smrj * Copyright 2007 Sun Microsystems, Inc. All rights reserved. 237c478bd9Sstevel@tonic-gate * Use is subject to license terms. 247c478bd9Sstevel@tonic-gate */ 257c478bd9Sstevel@tonic-gate 267c478bd9Sstevel@tonic-gate #pragma ident "%Z%%M% %I% %E% SMI" 277c478bd9Sstevel@tonic-gate 287c478bd9Sstevel@tonic-gate /* 297c478bd9Sstevel@tonic-gate * VM - page locking primitives 307c478bd9Sstevel@tonic-gate */ 317c478bd9Sstevel@tonic-gate #include <sys/param.h> 327c478bd9Sstevel@tonic-gate #include <sys/t_lock.h> 337c478bd9Sstevel@tonic-gate #include <sys/vtrace.h> 347c478bd9Sstevel@tonic-gate #include <sys/debug.h> 357c478bd9Sstevel@tonic-gate #include <sys/cmn_err.h> 367c478bd9Sstevel@tonic-gate #include <sys/vnode.h> 377c478bd9Sstevel@tonic-gate #include <sys/bitmap.h> 387c478bd9Sstevel@tonic-gate #include <sys/lockstat.h> 397c478bd9Sstevel@tonic-gate #include <sys/condvar_impl.h> 407c478bd9Sstevel@tonic-gate #include <vm/page.h> 417c478bd9Sstevel@tonic-gate #include <vm/seg_enum.h> 427c478bd9Sstevel@tonic-gate #include <vm/vm_dep.h> 437c478bd9Sstevel@tonic-gate 447c478bd9Sstevel@tonic-gate /* 457c478bd9Sstevel@tonic-gate * This global mutex is for logical page locking. 467c478bd9Sstevel@tonic-gate * The following fields in the page structure are protected 477c478bd9Sstevel@tonic-gate * by this lock: 487c478bd9Sstevel@tonic-gate * 497c478bd9Sstevel@tonic-gate * p_lckcnt 507c478bd9Sstevel@tonic-gate * p_cowcnt 517c478bd9Sstevel@tonic-gate */ 527c478bd9Sstevel@tonic-gate kmutex_t page_llock; 537c478bd9Sstevel@tonic-gate 547c478bd9Sstevel@tonic-gate /* 557c478bd9Sstevel@tonic-gate * This is a global lock for the logical page free list. The 567c478bd9Sstevel@tonic-gate * logical free list, in this implementation, is maintained as two 577c478bd9Sstevel@tonic-gate * separate physical lists - the cache list and the free list. 587c478bd9Sstevel@tonic-gate */ 597c478bd9Sstevel@tonic-gate kmutex_t page_freelock; 607c478bd9Sstevel@tonic-gate 617c478bd9Sstevel@tonic-gate /* 627c478bd9Sstevel@tonic-gate * The hash table, page_hash[], the p_selock fields, and the 637c478bd9Sstevel@tonic-gate * list of pages associated with vnodes are protected by arrays of mutexes. 647c478bd9Sstevel@tonic-gate * 657c478bd9Sstevel@tonic-gate * Unless the hashes are changed radically, the table sizes must be 667c478bd9Sstevel@tonic-gate * a power of two. Also, we typically need more mutexes for the 677c478bd9Sstevel@tonic-gate * vnodes since these locks are occasionally held for long periods. 687c478bd9Sstevel@tonic-gate * And since there seem to be two special vnodes (kvp and swapvp), 697c478bd9Sstevel@tonic-gate * we make room for private mutexes for them. 707c478bd9Sstevel@tonic-gate * 717c478bd9Sstevel@tonic-gate * The pse_mutex[] array holds the mutexes to protect the p_selock 727c478bd9Sstevel@tonic-gate * fields of all page_t structures. 737c478bd9Sstevel@tonic-gate * 747c478bd9Sstevel@tonic-gate * PAGE_SE_MUTEX(pp) returns the address of the appropriate mutex 757c478bd9Sstevel@tonic-gate * when given a pointer to a page_t. 767c478bd9Sstevel@tonic-gate * 777c478bd9Sstevel@tonic-gate * PSE_TABLE_SIZE must be a power of two. One could argue that we 787c478bd9Sstevel@tonic-gate * should go to the trouble of setting it up at run time and base it 797c478bd9Sstevel@tonic-gate * on memory size rather than the number of compile time CPUs. 807c478bd9Sstevel@tonic-gate * 817c478bd9Sstevel@tonic-gate * XX64 We should be using physmem size to calculate PSE_TABLE_SIZE, 827c478bd9Sstevel@tonic-gate * PSE_SHIFT, PIO_SHIFT. 837c478bd9Sstevel@tonic-gate * 847c478bd9Sstevel@tonic-gate * These might break in 64 bit world. 857c478bd9Sstevel@tonic-gate */ 867c478bd9Sstevel@tonic-gate #define PSE_SHIFT 7 /* log2(PSE_TABLE_SIZE) */ 877c478bd9Sstevel@tonic-gate 887c478bd9Sstevel@tonic-gate #define PSE_TABLE_SIZE 128 /* number of mutexes to have */ 897c478bd9Sstevel@tonic-gate 907c478bd9Sstevel@tonic-gate #define PIO_SHIFT PSE_SHIFT /* next power of 2 bigger than page_t */ 917c478bd9Sstevel@tonic-gate #define PIO_TABLE_SIZE PSE_TABLE_SIZE /* number of io mutexes to have */ 927c478bd9Sstevel@tonic-gate 937c478bd9Sstevel@tonic-gate pad_mutex_t ph_mutex[PH_TABLE_SIZE]; 947c478bd9Sstevel@tonic-gate pad_mutex_t pse_mutex[PSE_TABLE_SIZE]; 957c478bd9Sstevel@tonic-gate kmutex_t pio_mutex[PIO_TABLE_SIZE]; 967c478bd9Sstevel@tonic-gate 977c478bd9Sstevel@tonic-gate #define PAGE_SE_MUTEX(pp) \ 987c478bd9Sstevel@tonic-gate &pse_mutex[((((uintptr_t)(pp) >> PSE_SHIFT) ^ \ 997c478bd9Sstevel@tonic-gate ((uintptr_t)(pp) >> (PSE_SHIFT << 1))) & \ 1007c478bd9Sstevel@tonic-gate (PSE_TABLE_SIZE - 1))].pad_mutex 1017c478bd9Sstevel@tonic-gate 1027c478bd9Sstevel@tonic-gate #define PAGE_IO_MUTEX(pp) \ 1037c478bd9Sstevel@tonic-gate &pio_mutex[(((uintptr_t)pp) >> PIO_SHIFT) & (PIO_TABLE_SIZE - 1)] 1047c478bd9Sstevel@tonic-gate 1057c478bd9Sstevel@tonic-gate #define PSZC_MTX_TABLE_SIZE 128 1067c478bd9Sstevel@tonic-gate #define PSZC_MTX_TABLE_SHIFT 7 1077c478bd9Sstevel@tonic-gate 1087c478bd9Sstevel@tonic-gate static pad_mutex_t pszc_mutex[PSZC_MTX_TABLE_SIZE]; 1097c478bd9Sstevel@tonic-gate 1107c478bd9Sstevel@tonic-gate #define PAGE_SZC_MUTEX(_pp) \ 1117c478bd9Sstevel@tonic-gate &pszc_mutex[((((uintptr_t)(_pp) >> PSZC_MTX_TABLE_SHIFT) ^ \ 1127c478bd9Sstevel@tonic-gate ((uintptr_t)(_pp) >> (PSZC_MTX_TABLE_SHIFT << 1)) ^ \ 1137c478bd9Sstevel@tonic-gate ((uintptr_t)(_pp) >> (3 * PSZC_MTX_TABLE_SHIFT))) & \ 1147c478bd9Sstevel@tonic-gate (PSZC_MTX_TABLE_SIZE - 1))].pad_mutex 1157c478bd9Sstevel@tonic-gate 1167c478bd9Sstevel@tonic-gate /* 1177c478bd9Sstevel@tonic-gate * The vph_mutex[] array holds the mutexes to protect the vnode chains, 1187c478bd9Sstevel@tonic-gate * (i.e., the list of pages anchored by v_pages and connected via p_vpprev 1197c478bd9Sstevel@tonic-gate * and p_vpnext). 1207c478bd9Sstevel@tonic-gate * 1217c478bd9Sstevel@tonic-gate * The page_vnode_mutex(vp) function returns the address of the appropriate 1227c478bd9Sstevel@tonic-gate * mutex from this array given a pointer to a vnode. It is complicated 1237c478bd9Sstevel@tonic-gate * by the fact that the kernel's vnode and the swapfs vnode are referenced 1247c478bd9Sstevel@tonic-gate * frequently enough to warrent their own mutexes. 1257c478bd9Sstevel@tonic-gate * 1267c478bd9Sstevel@tonic-gate * The VP_HASH_FUNC returns the index into the vph_mutex array given 1277c478bd9Sstevel@tonic-gate * an address of a vnode. 1287c478bd9Sstevel@tonic-gate */ 1297c478bd9Sstevel@tonic-gate 1307c478bd9Sstevel@tonic-gate /* 1317c478bd9Sstevel@tonic-gate * XX64 VPH_TABLE_SIZE and VP_HASH_FUNC might break in 64 bit world. 1327c478bd9Sstevel@tonic-gate * Need to review again. 1337c478bd9Sstevel@tonic-gate */ 134*ac52b00eSqiao #if defined(_LP64) 135*ac52b00eSqiao #define VPH_TABLE_SIZE (1 << (VP_SHIFT + 3)) 136*ac52b00eSqiao #else /* 32 bits */ 1377c478bd9Sstevel@tonic-gate #define VPH_TABLE_SIZE (2 << VP_SHIFT) 138*ac52b00eSqiao #endif 1397c478bd9Sstevel@tonic-gate 1407c478bd9Sstevel@tonic-gate #define VP_HASH_FUNC(vp) \ 1417c478bd9Sstevel@tonic-gate ((((uintptr_t)(vp) >> 6) + \ 1427c478bd9Sstevel@tonic-gate ((uintptr_t)(vp) >> 8) + \ 1437c478bd9Sstevel@tonic-gate ((uintptr_t)(vp) >> 10) + \ 1447c478bd9Sstevel@tonic-gate ((uintptr_t)(vp) >> 12)) \ 1457c478bd9Sstevel@tonic-gate & (VPH_TABLE_SIZE - 1)) 1467c478bd9Sstevel@tonic-gate 1477c478bd9Sstevel@tonic-gate extern struct vnode kvp; 1487c478bd9Sstevel@tonic-gate 149ad23a2dbSjohansen /* 150ad23a2dbSjohansen * Two slots after VPH_TABLE_SIZE are reserved in vph_mutex for kernel vnodes. 151ad23a2dbSjohansen * The lock for kvp is VPH_TABLE_SIZE + 0, and the lock for zvp is 152ad23a2dbSjohansen * VPH_TABLE_SIZE + 1. 153ad23a2dbSjohansen */ 154ad23a2dbSjohansen 1557c478bd9Sstevel@tonic-gate kmutex_t vph_mutex[VPH_TABLE_SIZE + 2]; 1567c478bd9Sstevel@tonic-gate 1577c478bd9Sstevel@tonic-gate /* 1587c478bd9Sstevel@tonic-gate * Initialize the locks used by the Virtual Memory Management system. 1597c478bd9Sstevel@tonic-gate */ 1607c478bd9Sstevel@tonic-gate void 1617c478bd9Sstevel@tonic-gate page_lock_init() 1627c478bd9Sstevel@tonic-gate { 1637c478bd9Sstevel@tonic-gate } 1647c478bd9Sstevel@tonic-gate 1657c478bd9Sstevel@tonic-gate /* 1667c478bd9Sstevel@tonic-gate * At present we only use page ownership to aid debugging, so it's 1677c478bd9Sstevel@tonic-gate * OK if the owner field isn't exact. In the 32-bit world two thread ids 1687c478bd9Sstevel@tonic-gate * can map to the same owner because we just 'or' in 0x80000000 and 1697c478bd9Sstevel@tonic-gate * then clear the second highest bit, so that (for example) 0x2faced00 1707c478bd9Sstevel@tonic-gate * and 0xafaced00 both map to 0xafaced00. 1717c478bd9Sstevel@tonic-gate * In the 64-bit world, p_selock may not be large enough to hold a full 1727c478bd9Sstevel@tonic-gate * thread pointer. If we ever need precise ownership (e.g. if we implement 1737c478bd9Sstevel@tonic-gate * priority inheritance for page locks) then p_selock should become a 1747c478bd9Sstevel@tonic-gate * uintptr_t and SE_WRITER should be -((uintptr_t)curthread >> 2). 1757c478bd9Sstevel@tonic-gate */ 1767c478bd9Sstevel@tonic-gate #define SE_WRITER (((selock_t)(ulong_t)curthread | INT_MIN) & ~SE_EWANTED) 1777c478bd9Sstevel@tonic-gate #define SE_READER 1 1787c478bd9Sstevel@tonic-gate 1797c478bd9Sstevel@tonic-gate /* 1807c478bd9Sstevel@tonic-gate * A page that is deleted must be marked as such using the 1817c478bd9Sstevel@tonic-gate * page_lock_delete() function. The page must be exclusively locked. 1827c478bd9Sstevel@tonic-gate * The SE_DELETED marker is put in p_selock when this function is called. 1837c478bd9Sstevel@tonic-gate * SE_DELETED must be distinct from any SE_WRITER value. 1847c478bd9Sstevel@tonic-gate */ 1857c478bd9Sstevel@tonic-gate #define SE_DELETED (1 | INT_MIN) 1867c478bd9Sstevel@tonic-gate 1877c478bd9Sstevel@tonic-gate #ifdef VM_STATS 1887c478bd9Sstevel@tonic-gate uint_t vph_kvp_count; 1897c478bd9Sstevel@tonic-gate uint_t vph_swapfsvp_count; 1907c478bd9Sstevel@tonic-gate uint_t vph_other; 1917c478bd9Sstevel@tonic-gate #endif /* VM_STATS */ 1927c478bd9Sstevel@tonic-gate 1937c478bd9Sstevel@tonic-gate #ifdef VM_STATS 1947c478bd9Sstevel@tonic-gate uint_t page_lock_count; 1957c478bd9Sstevel@tonic-gate uint_t page_lock_miss; 1967c478bd9Sstevel@tonic-gate uint_t page_lock_miss_lock; 1977c478bd9Sstevel@tonic-gate uint_t page_lock_reclaim; 1987c478bd9Sstevel@tonic-gate uint_t page_lock_bad_reclaim; 1997c478bd9Sstevel@tonic-gate uint_t page_lock_same_page; 2007c478bd9Sstevel@tonic-gate uint_t page_lock_upgrade; 201db874c57Selowe uint_t page_lock_retired; 2027c478bd9Sstevel@tonic-gate uint_t page_lock_upgrade_failed; 2037c478bd9Sstevel@tonic-gate uint_t page_lock_deleted; 2047c478bd9Sstevel@tonic-gate 2057c478bd9Sstevel@tonic-gate uint_t page_trylock_locked; 206db874c57Selowe uint_t page_trylock_failed; 2077c478bd9Sstevel@tonic-gate uint_t page_trylock_missed; 2087c478bd9Sstevel@tonic-gate 2097c478bd9Sstevel@tonic-gate uint_t page_try_reclaim_upgrade; 2107c478bd9Sstevel@tonic-gate #endif /* VM_STATS */ 2117c478bd9Sstevel@tonic-gate 2127c478bd9Sstevel@tonic-gate /* 2137c478bd9Sstevel@tonic-gate * Acquire the "shared/exclusive" lock on a page. 2147c478bd9Sstevel@tonic-gate * 2157c478bd9Sstevel@tonic-gate * Returns 1 on success and locks the page appropriately. 2167c478bd9Sstevel@tonic-gate * 0 on failure and does not lock the page. 2177c478bd9Sstevel@tonic-gate * 2187c478bd9Sstevel@tonic-gate * If `lock' is non-NULL, it will be dropped and reacquired in the 2197c478bd9Sstevel@tonic-gate * failure case. This routine can block, and if it does 2207c478bd9Sstevel@tonic-gate * it will always return a failure since the page identity [vp, off] 2217c478bd9Sstevel@tonic-gate * or state may have changed. 2227c478bd9Sstevel@tonic-gate */ 2237c478bd9Sstevel@tonic-gate 2247c478bd9Sstevel@tonic-gate int 2257c478bd9Sstevel@tonic-gate page_lock(page_t *pp, se_t se, kmutex_t *lock, reclaim_t reclaim) 2267c478bd9Sstevel@tonic-gate { 2277c478bd9Sstevel@tonic-gate return (page_lock_es(pp, se, lock, reclaim, 0)); 2287c478bd9Sstevel@tonic-gate } 2297c478bd9Sstevel@tonic-gate 2307c478bd9Sstevel@tonic-gate /* 2317c478bd9Sstevel@tonic-gate * With the addition of reader-writer lock semantics to page_lock_es, 2327c478bd9Sstevel@tonic-gate * callers wanting an exclusive (writer) lock may prevent shared-lock 2337c478bd9Sstevel@tonic-gate * (reader) starvation by setting the es parameter to SE_EXCL_WANTED. 2347c478bd9Sstevel@tonic-gate * In this case, when an exclusive lock cannot be acquired, p_selock's 235db874c57Selowe * SE_EWANTED bit is set. Shared-lock (reader) requests are also denied 236db874c57Selowe * if the page is slated for retirement. 237db874c57Selowe * 238db874c57Selowe * The se and es parameters determine if the lock should be granted 239db874c57Selowe * based on the following decision table: 240db874c57Selowe * 241db874c57Selowe * Lock wanted es flags p_selock/SE_EWANTED Action 242db874c57Selowe * ----------- -------------- ------------------- --------- 243db874c57Selowe * SE_EXCL any [1][2] unlocked/any grant lock, clear SE_EWANTED 244db874c57Selowe * SE_EXCL SE_EWANTED any lock/any deny, set SE_EWANTED 245db874c57Selowe * SE_EXCL none any lock/any deny 2468bc68872Selowe * SE_SHARED n/a [2] shared/0 grant 2478bc68872Selowe * SE_SHARED n/a [2] unlocked/0 grant 248db874c57Selowe * SE_SHARED n/a shared/1 deny 249db874c57Selowe * SE_SHARED n/a unlocked/1 deny 250db874c57Selowe * SE_SHARED n/a excl/any deny 251db874c57Selowe * 252db874c57Selowe * Notes: 253db874c57Selowe * [1] The code grants an exclusive lock to the caller and clears the bit 254db874c57Selowe * SE_EWANTED whenever p_selock is unlocked, regardless of the SE_EWANTED 255db874c57Selowe * bit's value. This was deemed acceptable as we are not concerned about 256db874c57Selowe * exclusive-lock starvation. If this ever becomes an issue, a priority or 257db874c57Selowe * fifo mechanism should also be implemented. Meantime, the thread that 258db874c57Selowe * set SE_EWANTED should be prepared to catch this condition and reset it 259db874c57Selowe * 260db874c57Selowe * [2] Retired pages may not be locked at any time, regardless of the 261db874c57Selowe * dispostion of se, unless the es parameter has SE_RETIRED flag set. 2627c478bd9Sstevel@tonic-gate * 263db874c57Selowe * Notes on values of "es": 264db874c57Selowe * 265db874c57Selowe * es & 1: page_lookup_create will attempt page relocation 266db874c57Selowe * es & SE_EXCL_WANTED: caller wants SE_EWANTED set (eg. delete 267db874c57Selowe * memory thread); this prevents reader-starvation of waiting 268db874c57Selowe * writer thread(s) by giving priority to writers over readers. 269db874c57Selowe * es & SE_RETIRED: caller wants to lock pages even if they are 270db874c57Selowe * retired. Default is to deny the lock if the page is retired. 271db874c57Selowe * 272db874c57Selowe * And yes, we know, the semantics of this function are too complicated. 273db874c57Selowe * It's on the list to be cleaned up. 2747c478bd9Sstevel@tonic-gate */ 2757c478bd9Sstevel@tonic-gate int 2767c478bd9Sstevel@tonic-gate page_lock_es(page_t *pp, se_t se, kmutex_t *lock, reclaim_t reclaim, int es) 2777c478bd9Sstevel@tonic-gate { 2787c478bd9Sstevel@tonic-gate int retval; 2797c478bd9Sstevel@tonic-gate kmutex_t *pse = PAGE_SE_MUTEX(pp); 2807c478bd9Sstevel@tonic-gate int upgraded; 2817c478bd9Sstevel@tonic-gate int reclaim_it; 2827c478bd9Sstevel@tonic-gate 2837c478bd9Sstevel@tonic-gate ASSERT(lock != NULL ? MUTEX_HELD(lock) : 1); 2847c478bd9Sstevel@tonic-gate 2857c478bd9Sstevel@tonic-gate VM_STAT_ADD(page_lock_count); 2867c478bd9Sstevel@tonic-gate 2877c478bd9Sstevel@tonic-gate upgraded = 0; 2887c478bd9Sstevel@tonic-gate reclaim_it = 0; 2897c478bd9Sstevel@tonic-gate 2907c478bd9Sstevel@tonic-gate mutex_enter(pse); 2917c478bd9Sstevel@tonic-gate 2927c478bd9Sstevel@tonic-gate ASSERT(((es & SE_EXCL_WANTED) == 0) || 293db874c57Selowe ((es & SE_EXCL_WANTED) && (se == SE_EXCL))); 294db874c57Selowe 295db874c57Selowe if (PP_RETIRED(pp) && !(es & SE_RETIRED)) { 296db874c57Selowe mutex_exit(pse); 297db874c57Selowe VM_STAT_ADD(page_lock_retired); 298db874c57Selowe return (0); 299db874c57Selowe } 3007c478bd9Sstevel@tonic-gate 3017c478bd9Sstevel@tonic-gate if (se == SE_SHARED && es == 1 && pp->p_selock == 0) { 3027c478bd9Sstevel@tonic-gate se = SE_EXCL; 3037c478bd9Sstevel@tonic-gate } 3047c478bd9Sstevel@tonic-gate 3057c478bd9Sstevel@tonic-gate if ((reclaim == P_RECLAIM) && (PP_ISFREE(pp))) { 3067c478bd9Sstevel@tonic-gate 3077c478bd9Sstevel@tonic-gate reclaim_it = 1; 3087c478bd9Sstevel@tonic-gate if (se == SE_SHARED) { 3097c478bd9Sstevel@tonic-gate /* 3107c478bd9Sstevel@tonic-gate * This is an interesting situation. 3117c478bd9Sstevel@tonic-gate * 3127c478bd9Sstevel@tonic-gate * Remember that p_free can only change if 3137c478bd9Sstevel@tonic-gate * p_selock < 0. 3147c478bd9Sstevel@tonic-gate * p_free does not depend on our holding `pse'. 3157c478bd9Sstevel@tonic-gate * And, since we hold `pse', p_selock can not change. 3167c478bd9Sstevel@tonic-gate * So, if p_free changes on us, the page is already 3177c478bd9Sstevel@tonic-gate * exclusively held, and we would fail to get p_selock 3187c478bd9Sstevel@tonic-gate * regardless. 3197c478bd9Sstevel@tonic-gate * 3207c478bd9Sstevel@tonic-gate * We want to avoid getting the share 3217c478bd9Sstevel@tonic-gate * lock on a free page that needs to be reclaimed. 3227c478bd9Sstevel@tonic-gate * It is possible that some other thread has the share 3237c478bd9Sstevel@tonic-gate * lock and has left the free page on the cache list. 3247c478bd9Sstevel@tonic-gate * pvn_vplist_dirty() does this for brief periods. 3257c478bd9Sstevel@tonic-gate * If the se_share is currently SE_EXCL, we will fail 3267c478bd9Sstevel@tonic-gate * to acquire p_selock anyway. Blocking is the 3277c478bd9Sstevel@tonic-gate * right thing to do. 3287c478bd9Sstevel@tonic-gate * If we need to reclaim this page, we must get 3297c478bd9Sstevel@tonic-gate * exclusive access to it, force the upgrade now. 3307c478bd9Sstevel@tonic-gate * Again, we will fail to acquire p_selock if the 3317c478bd9Sstevel@tonic-gate * page is not free and block. 3327c478bd9Sstevel@tonic-gate */ 3337c478bd9Sstevel@tonic-gate upgraded = 1; 3347c478bd9Sstevel@tonic-gate se = SE_EXCL; 3357c478bd9Sstevel@tonic-gate VM_STAT_ADD(page_lock_upgrade); 3367c478bd9Sstevel@tonic-gate } 3377c478bd9Sstevel@tonic-gate } 3387c478bd9Sstevel@tonic-gate 3397c478bd9Sstevel@tonic-gate if (se == SE_EXCL) { 340db874c57Selowe if (!(es & SE_EXCL_WANTED) && (pp->p_selock & SE_EWANTED)) { 3417c478bd9Sstevel@tonic-gate /* 3427c478bd9Sstevel@tonic-gate * if the caller wants a writer lock (but did not 3437c478bd9Sstevel@tonic-gate * specify exclusive access), and there is a pending 3447c478bd9Sstevel@tonic-gate * writer that wants exclusive access, return failure 3457c478bd9Sstevel@tonic-gate */ 3467c478bd9Sstevel@tonic-gate retval = 0; 3477c478bd9Sstevel@tonic-gate } else if ((pp->p_selock & ~SE_EWANTED) == 0) { 3487c478bd9Sstevel@tonic-gate /* no reader/writer lock held */ 3497c478bd9Sstevel@tonic-gate THREAD_KPRI_REQUEST(); 3507c478bd9Sstevel@tonic-gate /* this clears our setting of the SE_EWANTED bit */ 3517c478bd9Sstevel@tonic-gate pp->p_selock = SE_WRITER; 3527c478bd9Sstevel@tonic-gate retval = 1; 3537c478bd9Sstevel@tonic-gate } else { 3547c478bd9Sstevel@tonic-gate /* page is locked */ 355db874c57Selowe if (es & SE_EXCL_WANTED) { 3567c478bd9Sstevel@tonic-gate /* set the SE_EWANTED bit */ 3577c478bd9Sstevel@tonic-gate pp->p_selock |= SE_EWANTED; 3587c478bd9Sstevel@tonic-gate } 3597c478bd9Sstevel@tonic-gate retval = 0; 3607c478bd9Sstevel@tonic-gate } 3617c478bd9Sstevel@tonic-gate } else { 3627c478bd9Sstevel@tonic-gate retval = 0; 3637c478bd9Sstevel@tonic-gate if (pp->p_selock >= 0) { 364db874c57Selowe if ((pp->p_selock & SE_EWANTED) == 0) { 3658bc68872Selowe pp->p_selock += SE_READER; 3668bc68872Selowe retval = 1; 3677c478bd9Sstevel@tonic-gate } 3687c478bd9Sstevel@tonic-gate } 3697c478bd9Sstevel@tonic-gate } 3707c478bd9Sstevel@tonic-gate 3717c478bd9Sstevel@tonic-gate if (retval == 0) { 3727c478bd9Sstevel@tonic-gate if ((pp->p_selock & ~SE_EWANTED) == SE_DELETED) { 3737c478bd9Sstevel@tonic-gate VM_STAT_ADD(page_lock_deleted); 3747c478bd9Sstevel@tonic-gate mutex_exit(pse); 3757c478bd9Sstevel@tonic-gate return (retval); 3767c478bd9Sstevel@tonic-gate } 3777c478bd9Sstevel@tonic-gate 3787c478bd9Sstevel@tonic-gate #ifdef VM_STATS 3797c478bd9Sstevel@tonic-gate VM_STAT_ADD(page_lock_miss); 3807c478bd9Sstevel@tonic-gate if (upgraded) { 3817c478bd9Sstevel@tonic-gate VM_STAT_ADD(page_lock_upgrade_failed); 3827c478bd9Sstevel@tonic-gate } 3837c478bd9Sstevel@tonic-gate #endif 3847c478bd9Sstevel@tonic-gate if (lock) { 3857c478bd9Sstevel@tonic-gate VM_STAT_ADD(page_lock_miss_lock); 3867c478bd9Sstevel@tonic-gate mutex_exit(lock); 3877c478bd9Sstevel@tonic-gate } 3887c478bd9Sstevel@tonic-gate 3897c478bd9Sstevel@tonic-gate /* 3907c478bd9Sstevel@tonic-gate * Now, wait for the page to be unlocked and 3917c478bd9Sstevel@tonic-gate * release the lock protecting p_cv and p_selock. 3927c478bd9Sstevel@tonic-gate */ 3937c478bd9Sstevel@tonic-gate cv_wait(&pp->p_cv, pse); 3947c478bd9Sstevel@tonic-gate mutex_exit(pse); 3957c478bd9Sstevel@tonic-gate 3967c478bd9Sstevel@tonic-gate /* 3977c478bd9Sstevel@tonic-gate * The page identity may have changed while we were 3987c478bd9Sstevel@tonic-gate * blocked. If we are willing to depend on "pp" 3997c478bd9Sstevel@tonic-gate * still pointing to a valid page structure (i.e., 4007c478bd9Sstevel@tonic-gate * assuming page structures are not dynamically allocated 4017c478bd9Sstevel@tonic-gate * or freed), we could try to lock the page if its 4027c478bd9Sstevel@tonic-gate * identity hasn't changed. 4037c478bd9Sstevel@tonic-gate * 4047c478bd9Sstevel@tonic-gate * This needs to be measured, since we come back from 4057c478bd9Sstevel@tonic-gate * cv_wait holding pse (the expensive part of this 4067c478bd9Sstevel@tonic-gate * operation) we might as well try the cheap part. 4077c478bd9Sstevel@tonic-gate * Though we would also have to confirm that dropping 4087c478bd9Sstevel@tonic-gate * `lock' did not cause any grief to the callers. 4097c478bd9Sstevel@tonic-gate */ 4107c478bd9Sstevel@tonic-gate if (lock) { 4117c478bd9Sstevel@tonic-gate mutex_enter(lock); 4127c478bd9Sstevel@tonic-gate } 4137c478bd9Sstevel@tonic-gate } else { 4147c478bd9Sstevel@tonic-gate /* 4157c478bd9Sstevel@tonic-gate * We have the page lock. 4167c478bd9Sstevel@tonic-gate * If we needed to reclaim the page, and the page 4177c478bd9Sstevel@tonic-gate * needed reclaiming (ie, it was free), then we 4187c478bd9Sstevel@tonic-gate * have the page exclusively locked. We may need 4197c478bd9Sstevel@tonic-gate * to downgrade the page. 4207c478bd9Sstevel@tonic-gate */ 4217c478bd9Sstevel@tonic-gate ASSERT((upgraded) ? 4227c478bd9Sstevel@tonic-gate ((PP_ISFREE(pp)) && PAGE_EXCL(pp)) : 1); 4237c478bd9Sstevel@tonic-gate mutex_exit(pse); 4247c478bd9Sstevel@tonic-gate 4257c478bd9Sstevel@tonic-gate /* 4267c478bd9Sstevel@tonic-gate * We now hold this page's lock, either shared or 4277c478bd9Sstevel@tonic-gate * exclusive. This will prevent its identity from changing. 4287c478bd9Sstevel@tonic-gate * The page, however, may or may not be free. If the caller 4297c478bd9Sstevel@tonic-gate * requested, and it is free, go reclaim it from the 4307c478bd9Sstevel@tonic-gate * free list. If the page can't be reclaimed, return failure 4317c478bd9Sstevel@tonic-gate * so that the caller can start all over again. 4327c478bd9Sstevel@tonic-gate * 4337c478bd9Sstevel@tonic-gate * NOTE:page_reclaim() releases the page lock (p_selock) 4347c478bd9Sstevel@tonic-gate * if it can't be reclaimed. 4357c478bd9Sstevel@tonic-gate */ 4367c478bd9Sstevel@tonic-gate if (reclaim_it) { 4377c478bd9Sstevel@tonic-gate if (!page_reclaim(pp, lock)) { 4387c478bd9Sstevel@tonic-gate VM_STAT_ADD(page_lock_bad_reclaim); 4397c478bd9Sstevel@tonic-gate retval = 0; 4407c478bd9Sstevel@tonic-gate } else { 4417c478bd9Sstevel@tonic-gate VM_STAT_ADD(page_lock_reclaim); 4427c478bd9Sstevel@tonic-gate if (upgraded) { 4437c478bd9Sstevel@tonic-gate page_downgrade(pp); 4447c478bd9Sstevel@tonic-gate } 4457c478bd9Sstevel@tonic-gate } 4467c478bd9Sstevel@tonic-gate } 4477c478bd9Sstevel@tonic-gate } 4487c478bd9Sstevel@tonic-gate return (retval); 4497c478bd9Sstevel@tonic-gate } 4507c478bd9Sstevel@tonic-gate 4517c478bd9Sstevel@tonic-gate /* 4527c478bd9Sstevel@tonic-gate * Clear the SE_EWANTED bit from p_selock. This function allows 4537c478bd9Sstevel@tonic-gate * callers of page_lock_es and page_try_reclaim_lock to clear 4547c478bd9Sstevel@tonic-gate * their setting of this bit if they decide they no longer wish 4557c478bd9Sstevel@tonic-gate * to gain exclusive access to the page. Currently only 4567c478bd9Sstevel@tonic-gate * delete_memory_thread uses this when the delete memory 4577c478bd9Sstevel@tonic-gate * operation is cancelled. 4587c478bd9Sstevel@tonic-gate */ 4597c478bd9Sstevel@tonic-gate void 4607c478bd9Sstevel@tonic-gate page_lock_clr_exclwanted(page_t *pp) 4617c478bd9Sstevel@tonic-gate { 4627c478bd9Sstevel@tonic-gate kmutex_t *pse = PAGE_SE_MUTEX(pp); 4637c478bd9Sstevel@tonic-gate 4647c478bd9Sstevel@tonic-gate mutex_enter(pse); 4657c478bd9Sstevel@tonic-gate pp->p_selock &= ~SE_EWANTED; 4667c478bd9Sstevel@tonic-gate if (CV_HAS_WAITERS(&pp->p_cv)) 4677c478bd9Sstevel@tonic-gate cv_broadcast(&pp->p_cv); 4687c478bd9Sstevel@tonic-gate mutex_exit(pse); 4697c478bd9Sstevel@tonic-gate } 4707c478bd9Sstevel@tonic-gate 4717c478bd9Sstevel@tonic-gate /* 4727c478bd9Sstevel@tonic-gate * Read the comments inside of page_lock_es() carefully. 4737c478bd9Sstevel@tonic-gate * 4747c478bd9Sstevel@tonic-gate * SE_EXCL callers specifying es == SE_EXCL_WANTED will cause the 4757c478bd9Sstevel@tonic-gate * SE_EWANTED bit of p_selock to be set when the lock cannot be obtained. 4767c478bd9Sstevel@tonic-gate * This is used by threads subject to reader-starvation (eg. memory delete). 4777c478bd9Sstevel@tonic-gate * 4787c478bd9Sstevel@tonic-gate * When a thread using SE_EXCL_WANTED does not obtain the SE_EXCL lock, 4797c478bd9Sstevel@tonic-gate * it is expected that it will retry at a later time. Threads that will 4807c478bd9Sstevel@tonic-gate * not retry the lock *must* call page_lock_clr_exclwanted to clear the 4817c478bd9Sstevel@tonic-gate * SE_EWANTED bit. (When a thread using SE_EXCL_WANTED obtains the lock, 4827c478bd9Sstevel@tonic-gate * the bit is cleared.) 4837c478bd9Sstevel@tonic-gate */ 4847c478bd9Sstevel@tonic-gate int 4857c478bd9Sstevel@tonic-gate page_try_reclaim_lock(page_t *pp, se_t se, int es) 4867c478bd9Sstevel@tonic-gate { 4877c478bd9Sstevel@tonic-gate kmutex_t *pse = PAGE_SE_MUTEX(pp); 4887c478bd9Sstevel@tonic-gate selock_t old; 4897c478bd9Sstevel@tonic-gate 4907c478bd9Sstevel@tonic-gate mutex_enter(pse); 4917c478bd9Sstevel@tonic-gate 4927c478bd9Sstevel@tonic-gate old = pp->p_selock; 4937c478bd9Sstevel@tonic-gate 4947c478bd9Sstevel@tonic-gate ASSERT(((es & SE_EXCL_WANTED) == 0) || 495db874c57Selowe ((es & SE_EXCL_WANTED) && (se == SE_EXCL))); 496db874c57Selowe 497db874c57Selowe if (PP_RETIRED(pp) && !(es & SE_RETIRED)) { 498db874c57Selowe mutex_exit(pse); 499db874c57Selowe VM_STAT_ADD(page_trylock_failed); 500db874c57Selowe return (0); 501db874c57Selowe } 5027c478bd9Sstevel@tonic-gate 5037c478bd9Sstevel@tonic-gate if (se == SE_SHARED && es == 1 && old == 0) { 5047c478bd9Sstevel@tonic-gate se = SE_EXCL; 5057c478bd9Sstevel@tonic-gate } 5067c478bd9Sstevel@tonic-gate 5077c478bd9Sstevel@tonic-gate if (se == SE_SHARED) { 5087c478bd9Sstevel@tonic-gate if (!PP_ISFREE(pp)) { 5097c478bd9Sstevel@tonic-gate if (old >= 0) { 510db874c57Selowe /* 511db874c57Selowe * Readers are not allowed when excl wanted 512db874c57Selowe */ 513db874c57Selowe if ((old & SE_EWANTED) == 0) { 5148bc68872Selowe pp->p_selock = old + SE_READER; 5158bc68872Selowe mutex_exit(pse); 5168bc68872Selowe return (1); 5177c478bd9Sstevel@tonic-gate } 5187c478bd9Sstevel@tonic-gate } 5197c478bd9Sstevel@tonic-gate mutex_exit(pse); 5207c478bd9Sstevel@tonic-gate return (0); 5217c478bd9Sstevel@tonic-gate } 5227c478bd9Sstevel@tonic-gate /* 5237c478bd9Sstevel@tonic-gate * The page is free, so we really want SE_EXCL (below) 5247c478bd9Sstevel@tonic-gate */ 5257c478bd9Sstevel@tonic-gate VM_STAT_ADD(page_try_reclaim_upgrade); 5267c478bd9Sstevel@tonic-gate } 5277c478bd9Sstevel@tonic-gate 5287c478bd9Sstevel@tonic-gate /* 5297c478bd9Sstevel@tonic-gate * The caller wants a writer lock. We try for it only if 5307c478bd9Sstevel@tonic-gate * SE_EWANTED is not set, or if the caller specified 5317c478bd9Sstevel@tonic-gate * SE_EXCL_WANTED. 5327c478bd9Sstevel@tonic-gate */ 533db874c57Selowe if (!(old & SE_EWANTED) || (es & SE_EXCL_WANTED)) { 5347c478bd9Sstevel@tonic-gate if ((old & ~SE_EWANTED) == 0) { 5357c478bd9Sstevel@tonic-gate /* no reader/writer lock held */ 5367c478bd9Sstevel@tonic-gate THREAD_KPRI_REQUEST(); 5377c478bd9Sstevel@tonic-gate /* this clears out our setting of the SE_EWANTED bit */ 5387c478bd9Sstevel@tonic-gate pp->p_selock = SE_WRITER; 5397c478bd9Sstevel@tonic-gate mutex_exit(pse); 5407c478bd9Sstevel@tonic-gate return (1); 5417c478bd9Sstevel@tonic-gate } 5427c478bd9Sstevel@tonic-gate } 543db874c57Selowe if (es & SE_EXCL_WANTED) { 5447c478bd9Sstevel@tonic-gate /* page is locked, set the SE_EWANTED bit */ 5457c478bd9Sstevel@tonic-gate pp->p_selock |= SE_EWANTED; 5467c478bd9Sstevel@tonic-gate } 5477c478bd9Sstevel@tonic-gate mutex_exit(pse); 5487c478bd9Sstevel@tonic-gate return (0); 5497c478bd9Sstevel@tonic-gate } 5507c478bd9Sstevel@tonic-gate 5517c478bd9Sstevel@tonic-gate /* 5527c478bd9Sstevel@tonic-gate * Acquire a page's "shared/exclusive" lock, but never block. 5537c478bd9Sstevel@tonic-gate * Returns 1 on success, 0 on failure. 5547c478bd9Sstevel@tonic-gate */ 5557c478bd9Sstevel@tonic-gate int 5567c478bd9Sstevel@tonic-gate page_trylock(page_t *pp, se_t se) 5577c478bd9Sstevel@tonic-gate { 5587c478bd9Sstevel@tonic-gate kmutex_t *pse = PAGE_SE_MUTEX(pp); 5597c478bd9Sstevel@tonic-gate 5607c478bd9Sstevel@tonic-gate mutex_enter(pse); 561db874c57Selowe if (pp->p_selock & SE_EWANTED || PP_RETIRED(pp) || 56224e9c58bSelowe (se == SE_SHARED && PP_PR_NOSHARE(pp))) { 563db874c57Selowe /* 564db874c57Selowe * Fail if a thread wants exclusive access and page is 565db874c57Selowe * retired, if the page is slated for retirement, or a 566db874c57Selowe * share lock is requested. 567db874c57Selowe */ 5687c478bd9Sstevel@tonic-gate mutex_exit(pse); 569db874c57Selowe VM_STAT_ADD(page_trylock_failed); 5707c478bd9Sstevel@tonic-gate return (0); 5717c478bd9Sstevel@tonic-gate } 5727c478bd9Sstevel@tonic-gate 5737c478bd9Sstevel@tonic-gate if (se == SE_EXCL) { 5747c478bd9Sstevel@tonic-gate if (pp->p_selock == 0) { 5757c478bd9Sstevel@tonic-gate THREAD_KPRI_REQUEST(); 5767c478bd9Sstevel@tonic-gate pp->p_selock = SE_WRITER; 5777c478bd9Sstevel@tonic-gate mutex_exit(pse); 5787c478bd9Sstevel@tonic-gate return (1); 5797c478bd9Sstevel@tonic-gate } 5807c478bd9Sstevel@tonic-gate } else { 5817c478bd9Sstevel@tonic-gate if (pp->p_selock >= 0) { 5827c478bd9Sstevel@tonic-gate pp->p_selock += SE_READER; 5837c478bd9Sstevel@tonic-gate mutex_exit(pse); 5847c478bd9Sstevel@tonic-gate return (1); 5857c478bd9Sstevel@tonic-gate } 5867c478bd9Sstevel@tonic-gate } 5877c478bd9Sstevel@tonic-gate mutex_exit(pse); 5887c478bd9Sstevel@tonic-gate return (0); 5897c478bd9Sstevel@tonic-gate } 5907c478bd9Sstevel@tonic-gate 591db874c57Selowe /* 592db874c57Selowe * Variant of page_unlock() specifically for the page freelist 593db874c57Selowe * code. The mere existence of this code is a vile hack that 594db874c57Selowe * has resulted due to the backwards locking order of the page 595db874c57Selowe * freelist manager; please don't call it. 596db874c57Selowe */ 597db874c57Selowe void 5988b464eb8Smec page_unlock_nocapture(page_t *pp) 599db874c57Selowe { 600db874c57Selowe kmutex_t *pse = PAGE_SE_MUTEX(pp); 601db874c57Selowe selock_t old; 602db874c57Selowe 603db874c57Selowe mutex_enter(pse); 604db874c57Selowe 605db874c57Selowe old = pp->p_selock; 606db874c57Selowe if ((old & ~SE_EWANTED) == SE_READER) { 607db874c57Selowe pp->p_selock = old & ~SE_READER; 608db874c57Selowe if (CV_HAS_WAITERS(&pp->p_cv)) 609db874c57Selowe cv_broadcast(&pp->p_cv); 610db874c57Selowe } else if ((old & ~SE_EWANTED) == SE_DELETED) { 6118b464eb8Smec panic("page_unlock_nocapture: page %p is deleted", pp); 612db874c57Selowe } else if (old < 0) { 613db874c57Selowe THREAD_KPRI_RELEASE(); 614db874c57Selowe pp->p_selock &= SE_EWANTED; 615db874c57Selowe if (CV_HAS_WAITERS(&pp->p_cv)) 616db874c57Selowe cv_broadcast(&pp->p_cv); 617db874c57Selowe } else if ((old & ~SE_EWANTED) > SE_READER) { 618db874c57Selowe pp->p_selock = old - SE_READER; 619db874c57Selowe } else { 6208b464eb8Smec panic("page_unlock_nocapture: page %p is not locked", pp); 621db874c57Selowe } 622db874c57Selowe 623db874c57Selowe mutex_exit(pse); 624db874c57Selowe } 625db874c57Selowe 6267c478bd9Sstevel@tonic-gate /* 6277c478bd9Sstevel@tonic-gate * Release the page's "shared/exclusive" lock and wake up anyone 6287c478bd9Sstevel@tonic-gate * who might be waiting for it. 6297c478bd9Sstevel@tonic-gate */ 6307c478bd9Sstevel@tonic-gate void 6317c478bd9Sstevel@tonic-gate page_unlock(page_t *pp) 6327c478bd9Sstevel@tonic-gate { 6337c478bd9Sstevel@tonic-gate kmutex_t *pse = PAGE_SE_MUTEX(pp); 6347c478bd9Sstevel@tonic-gate selock_t old; 6357c478bd9Sstevel@tonic-gate 6367c478bd9Sstevel@tonic-gate mutex_enter(pse); 637db874c57Selowe 6387c478bd9Sstevel@tonic-gate old = pp->p_selock; 6397c478bd9Sstevel@tonic-gate if ((old & ~SE_EWANTED) == SE_READER) { 6407c478bd9Sstevel@tonic-gate pp->p_selock = old & ~SE_READER; 6417c478bd9Sstevel@tonic-gate if (CV_HAS_WAITERS(&pp->p_cv)) 6427c478bd9Sstevel@tonic-gate cv_broadcast(&pp->p_cv); 6437c478bd9Sstevel@tonic-gate } else if ((old & ~SE_EWANTED) == SE_DELETED) { 6447c478bd9Sstevel@tonic-gate panic("page_unlock: page %p is deleted", pp); 6457c478bd9Sstevel@tonic-gate } else if (old < 0) { 6467c478bd9Sstevel@tonic-gate THREAD_KPRI_RELEASE(); 6477c478bd9Sstevel@tonic-gate pp->p_selock &= SE_EWANTED; 6487c478bd9Sstevel@tonic-gate if (CV_HAS_WAITERS(&pp->p_cv)) 6497c478bd9Sstevel@tonic-gate cv_broadcast(&pp->p_cv); 6507c478bd9Sstevel@tonic-gate } else if ((old & ~SE_EWANTED) > SE_READER) { 6517c478bd9Sstevel@tonic-gate pp->p_selock = old - SE_READER; 6527c478bd9Sstevel@tonic-gate } else { 6537c478bd9Sstevel@tonic-gate panic("page_unlock: page %p is not locked", pp); 6547c478bd9Sstevel@tonic-gate } 655db874c57Selowe 6568b464eb8Smec if (pp->p_selock == 0) { 657db874c57Selowe /* 6588b464eb8Smec * If the T_CAPTURING bit is set, that means that we should 6598b464eb8Smec * not try and capture the page again as we could recurse 6608b464eb8Smec * which could lead to a stack overflow panic or spending a 6618b464eb8Smec * relatively long time in the kernel making no progress. 662db874c57Selowe */ 6638b464eb8Smec if ((pp->p_toxic & PR_CAPTURE) && 6648b464eb8Smec !(curthread->t_flag & T_CAPTURING) && 6658b464eb8Smec !PP_RETIRED(pp)) { 666db874c57Selowe THREAD_KPRI_REQUEST(); 667db874c57Selowe pp->p_selock = SE_WRITER; 668db874c57Selowe mutex_exit(pse); 6698b464eb8Smec page_unlock_capture(pp); 670db874c57Selowe } else { 671db874c57Selowe mutex_exit(pse); 672db874c57Selowe } 673db874c57Selowe } else { 674db874c57Selowe mutex_exit(pse); 675db874c57Selowe } 6767c478bd9Sstevel@tonic-gate } 6777c478bd9Sstevel@tonic-gate 6787c478bd9Sstevel@tonic-gate /* 6797c478bd9Sstevel@tonic-gate * Try to upgrade the lock on the page from a "shared" to an 6807c478bd9Sstevel@tonic-gate * "exclusive" lock. Since this upgrade operation is done while 6817c478bd9Sstevel@tonic-gate * holding the mutex protecting this page, no one else can acquire this page's 6827c478bd9Sstevel@tonic-gate * lock and change the page. Thus, it is safe to drop the "shared" 6837c478bd9Sstevel@tonic-gate * lock and attempt to acquire the "exclusive" lock. 6847c478bd9Sstevel@tonic-gate * 6857c478bd9Sstevel@tonic-gate * Returns 1 on success, 0 on failure. 6867c478bd9Sstevel@tonic-gate */ 6877c478bd9Sstevel@tonic-gate int 6887c478bd9Sstevel@tonic-gate page_tryupgrade(page_t *pp) 6897c478bd9Sstevel@tonic-gate { 6907c478bd9Sstevel@tonic-gate kmutex_t *pse = PAGE_SE_MUTEX(pp); 6917c478bd9Sstevel@tonic-gate 6927c478bd9Sstevel@tonic-gate mutex_enter(pse); 6937c478bd9Sstevel@tonic-gate if (!(pp->p_selock & SE_EWANTED)) { 6947c478bd9Sstevel@tonic-gate /* no threads want exclusive access, try upgrade */ 6957c478bd9Sstevel@tonic-gate if (pp->p_selock == SE_READER) { 6967c478bd9Sstevel@tonic-gate THREAD_KPRI_REQUEST(); 6977c478bd9Sstevel@tonic-gate /* convert to exclusive lock */ 6987c478bd9Sstevel@tonic-gate pp->p_selock = SE_WRITER; 6997c478bd9Sstevel@tonic-gate mutex_exit(pse); 7007c478bd9Sstevel@tonic-gate return (1); 7017c478bd9Sstevel@tonic-gate } 7027c478bd9Sstevel@tonic-gate } 7037c478bd9Sstevel@tonic-gate mutex_exit(pse); 7047c478bd9Sstevel@tonic-gate return (0); 7057c478bd9Sstevel@tonic-gate } 7067c478bd9Sstevel@tonic-gate 7077c478bd9Sstevel@tonic-gate /* 7087c478bd9Sstevel@tonic-gate * Downgrade the "exclusive" lock on the page to a "shared" lock 7097c478bd9Sstevel@tonic-gate * while holding the mutex protecting this page's p_selock field. 7107c478bd9Sstevel@tonic-gate */ 7117c478bd9Sstevel@tonic-gate void 7127c478bd9Sstevel@tonic-gate page_downgrade(page_t *pp) 7137c478bd9Sstevel@tonic-gate { 7147c478bd9Sstevel@tonic-gate kmutex_t *pse = PAGE_SE_MUTEX(pp); 7157c478bd9Sstevel@tonic-gate int excl_waiting; 7167c478bd9Sstevel@tonic-gate 7177c478bd9Sstevel@tonic-gate ASSERT((pp->p_selock & ~SE_EWANTED) != SE_DELETED); 7187c478bd9Sstevel@tonic-gate ASSERT(PAGE_EXCL(pp)); 7197c478bd9Sstevel@tonic-gate 7207c478bd9Sstevel@tonic-gate mutex_enter(pse); 7217c478bd9Sstevel@tonic-gate excl_waiting = pp->p_selock & SE_EWANTED; 7227c478bd9Sstevel@tonic-gate THREAD_KPRI_RELEASE(); 7237c478bd9Sstevel@tonic-gate pp->p_selock = SE_READER | excl_waiting; 7247c478bd9Sstevel@tonic-gate if (CV_HAS_WAITERS(&pp->p_cv)) 7257c478bd9Sstevel@tonic-gate cv_broadcast(&pp->p_cv); 7267c478bd9Sstevel@tonic-gate mutex_exit(pse); 7277c478bd9Sstevel@tonic-gate } 7287c478bd9Sstevel@tonic-gate 7297c478bd9Sstevel@tonic-gate void 7307c478bd9Sstevel@tonic-gate page_lock_delete(page_t *pp) 7317c478bd9Sstevel@tonic-gate { 7327c478bd9Sstevel@tonic-gate kmutex_t *pse = PAGE_SE_MUTEX(pp); 7337c478bd9Sstevel@tonic-gate 7347c478bd9Sstevel@tonic-gate ASSERT(PAGE_EXCL(pp)); 7357c478bd9Sstevel@tonic-gate ASSERT(pp->p_vnode == NULL); 7367c478bd9Sstevel@tonic-gate ASSERT(pp->p_offset == (u_offset_t)-1); 7377c478bd9Sstevel@tonic-gate ASSERT(!PP_ISFREE(pp)); 7387c478bd9Sstevel@tonic-gate 7397c478bd9Sstevel@tonic-gate mutex_enter(pse); 7407c478bd9Sstevel@tonic-gate THREAD_KPRI_RELEASE(); 7417c478bd9Sstevel@tonic-gate pp->p_selock = SE_DELETED; 7427c478bd9Sstevel@tonic-gate if (CV_HAS_WAITERS(&pp->p_cv)) 7437c478bd9Sstevel@tonic-gate cv_broadcast(&pp->p_cv); 7447c478bd9Sstevel@tonic-gate mutex_exit(pse); 7457c478bd9Sstevel@tonic-gate } 7467c478bd9Sstevel@tonic-gate 7478b464eb8Smec int 7488b464eb8Smec page_deleted(page_t *pp) 7498b464eb8Smec { 7508b464eb8Smec return (pp->p_selock == SE_DELETED); 7518b464eb8Smec } 7528b464eb8Smec 7537c478bd9Sstevel@tonic-gate /* 7547c478bd9Sstevel@tonic-gate * Implement the io lock for pages 7557c478bd9Sstevel@tonic-gate */ 7567c478bd9Sstevel@tonic-gate void 7577c478bd9Sstevel@tonic-gate page_iolock_init(page_t *pp) 7587c478bd9Sstevel@tonic-gate { 7597c478bd9Sstevel@tonic-gate pp->p_iolock_state = 0; 7607c478bd9Sstevel@tonic-gate cv_init(&pp->p_io_cv, NULL, CV_DEFAULT, NULL); 7617c478bd9Sstevel@tonic-gate } 7627c478bd9Sstevel@tonic-gate 7637c478bd9Sstevel@tonic-gate /* 7647c478bd9Sstevel@tonic-gate * Acquire the i/o lock on a page. 7657c478bd9Sstevel@tonic-gate */ 7667c478bd9Sstevel@tonic-gate void 7677c478bd9Sstevel@tonic-gate page_io_lock(page_t *pp) 7687c478bd9Sstevel@tonic-gate { 7697c478bd9Sstevel@tonic-gate kmutex_t *pio; 7707c478bd9Sstevel@tonic-gate 7717c478bd9Sstevel@tonic-gate pio = PAGE_IO_MUTEX(pp); 7727c478bd9Sstevel@tonic-gate mutex_enter(pio); 7737c478bd9Sstevel@tonic-gate while (pp->p_iolock_state & PAGE_IO_INUSE) { 7747c478bd9Sstevel@tonic-gate cv_wait(&(pp->p_io_cv), pio); 7757c478bd9Sstevel@tonic-gate } 7767c478bd9Sstevel@tonic-gate pp->p_iolock_state |= PAGE_IO_INUSE; 7777c478bd9Sstevel@tonic-gate mutex_exit(pio); 7787c478bd9Sstevel@tonic-gate } 7797c478bd9Sstevel@tonic-gate 7807c478bd9Sstevel@tonic-gate /* 7817c478bd9Sstevel@tonic-gate * Release the i/o lock on a page. 7827c478bd9Sstevel@tonic-gate */ 7837c478bd9Sstevel@tonic-gate void 7847c478bd9Sstevel@tonic-gate page_io_unlock(page_t *pp) 7857c478bd9Sstevel@tonic-gate { 7867c478bd9Sstevel@tonic-gate kmutex_t *pio; 7877c478bd9Sstevel@tonic-gate 7887c478bd9Sstevel@tonic-gate pio = PAGE_IO_MUTEX(pp); 7897c478bd9Sstevel@tonic-gate mutex_enter(pio); 790a71e32b6Sstans cv_broadcast(&pp->p_io_cv); 7917c478bd9Sstevel@tonic-gate pp->p_iolock_state &= ~PAGE_IO_INUSE; 7927c478bd9Sstevel@tonic-gate mutex_exit(pio); 7937c478bd9Sstevel@tonic-gate } 7947c478bd9Sstevel@tonic-gate 7957c478bd9Sstevel@tonic-gate /* 7967c478bd9Sstevel@tonic-gate * Try to acquire the i/o lock on a page without blocking. 7977c478bd9Sstevel@tonic-gate * Returns 1 on success, 0 on failure. 7987c478bd9Sstevel@tonic-gate */ 7997c478bd9Sstevel@tonic-gate int 8007c478bd9Sstevel@tonic-gate page_io_trylock(page_t *pp) 8017c478bd9Sstevel@tonic-gate { 8027c478bd9Sstevel@tonic-gate kmutex_t *pio; 8037c478bd9Sstevel@tonic-gate 8047c478bd9Sstevel@tonic-gate if (pp->p_iolock_state & PAGE_IO_INUSE) 8057c478bd9Sstevel@tonic-gate return (0); 8067c478bd9Sstevel@tonic-gate 8077c478bd9Sstevel@tonic-gate pio = PAGE_IO_MUTEX(pp); 8087c478bd9Sstevel@tonic-gate mutex_enter(pio); 8097c478bd9Sstevel@tonic-gate 8107c478bd9Sstevel@tonic-gate if (pp->p_iolock_state & PAGE_IO_INUSE) { 8117c478bd9Sstevel@tonic-gate mutex_exit(pio); 8127c478bd9Sstevel@tonic-gate return (0); 8137c478bd9Sstevel@tonic-gate } 8147c478bd9Sstevel@tonic-gate pp->p_iolock_state |= PAGE_IO_INUSE; 8157c478bd9Sstevel@tonic-gate mutex_exit(pio); 8167c478bd9Sstevel@tonic-gate 8177c478bd9Sstevel@tonic-gate return (1); 8187c478bd9Sstevel@tonic-gate } 8197c478bd9Sstevel@tonic-gate 820a71e32b6Sstans /* 821a71e32b6Sstans * Wait until the i/o lock is not held. 822a71e32b6Sstans */ 823a71e32b6Sstans void 824a71e32b6Sstans page_io_wait(page_t *pp) 825a71e32b6Sstans { 826a71e32b6Sstans kmutex_t *pio; 827a71e32b6Sstans 828a71e32b6Sstans pio = PAGE_IO_MUTEX(pp); 829a71e32b6Sstans mutex_enter(pio); 830a71e32b6Sstans while (pp->p_iolock_state & PAGE_IO_INUSE) { 831a71e32b6Sstans cv_wait(&(pp->p_io_cv), pio); 832a71e32b6Sstans } 833a71e32b6Sstans mutex_exit(pio); 834a71e32b6Sstans } 835a71e32b6Sstans 836a71e32b6Sstans /* 837a71e32b6Sstans * Returns 1 on success, 0 on failure. 838a71e32b6Sstans */ 839a71e32b6Sstans int 840a71e32b6Sstans page_io_locked(page_t *pp) 841a71e32b6Sstans { 842a71e32b6Sstans return (pp->p_iolock_state & PAGE_IO_INUSE); 843a71e32b6Sstans } 844a71e32b6Sstans 8457c478bd9Sstevel@tonic-gate /* 8467c478bd9Sstevel@tonic-gate * Assert that the i/o lock on a page is held. 8477c478bd9Sstevel@tonic-gate * Returns 1 on success, 0 on failure. 8487c478bd9Sstevel@tonic-gate */ 8497c478bd9Sstevel@tonic-gate int 8507c478bd9Sstevel@tonic-gate page_iolock_assert(page_t *pp) 8517c478bd9Sstevel@tonic-gate { 852a71e32b6Sstans return (page_io_locked(pp)); 8537c478bd9Sstevel@tonic-gate } 8547c478bd9Sstevel@tonic-gate 8557c478bd9Sstevel@tonic-gate /* 8567c478bd9Sstevel@tonic-gate * Wrapper exported to kernel routines that are built 8577c478bd9Sstevel@tonic-gate * platform-independent (the macro is platform-dependent; 8587c478bd9Sstevel@tonic-gate * the size of vph_mutex[] is based on NCPU). 8597c478bd9Sstevel@tonic-gate * 8607c478bd9Sstevel@tonic-gate * Note that you can do stress testing on this by setting the 8617c478bd9Sstevel@tonic-gate * variable page_vnode_mutex_stress to something other than 8627c478bd9Sstevel@tonic-gate * zero in a DEBUG kernel in a debugger after loading the kernel. 8637c478bd9Sstevel@tonic-gate * Setting it after the kernel is running may not work correctly. 8647c478bd9Sstevel@tonic-gate */ 8657c478bd9Sstevel@tonic-gate #ifdef DEBUG 8667c478bd9Sstevel@tonic-gate static int page_vnode_mutex_stress = 0; 8677c478bd9Sstevel@tonic-gate #endif 8687c478bd9Sstevel@tonic-gate 8697c478bd9Sstevel@tonic-gate kmutex_t * 8707c478bd9Sstevel@tonic-gate page_vnode_mutex(vnode_t *vp) 8717c478bd9Sstevel@tonic-gate { 8727c478bd9Sstevel@tonic-gate if (vp == &kvp) 8737c478bd9Sstevel@tonic-gate return (&vph_mutex[VPH_TABLE_SIZE + 0]); 874ad23a2dbSjohansen 875ad23a2dbSjohansen if (vp == &zvp) 876ad23a2dbSjohansen return (&vph_mutex[VPH_TABLE_SIZE + 1]); 8777c478bd9Sstevel@tonic-gate #ifdef DEBUG 8787c478bd9Sstevel@tonic-gate if (page_vnode_mutex_stress != 0) 8797c478bd9Sstevel@tonic-gate return (&vph_mutex[0]); 8807c478bd9Sstevel@tonic-gate #endif 8817c478bd9Sstevel@tonic-gate 8827c478bd9Sstevel@tonic-gate return (&vph_mutex[VP_HASH_FUNC(vp)]); 8837c478bd9Sstevel@tonic-gate } 8847c478bd9Sstevel@tonic-gate 8857c478bd9Sstevel@tonic-gate kmutex_t * 8867c478bd9Sstevel@tonic-gate page_se_mutex(page_t *pp) 8877c478bd9Sstevel@tonic-gate { 8887c478bd9Sstevel@tonic-gate return (PAGE_SE_MUTEX(pp)); 8897c478bd9Sstevel@tonic-gate } 8907c478bd9Sstevel@tonic-gate 8917c478bd9Sstevel@tonic-gate #ifdef VM_STATS 8927c478bd9Sstevel@tonic-gate uint_t pszclck_stat[4]; 8937c478bd9Sstevel@tonic-gate #endif 8947c478bd9Sstevel@tonic-gate /* 8957c478bd9Sstevel@tonic-gate * Find, take and return a mutex held by hat_page_demote(). 8967c478bd9Sstevel@tonic-gate * Called by page_demote_vp_pages() before hat_page_demote() call and by 8977c478bd9Sstevel@tonic-gate * routines that want to block hat_page_demote() but can't do it 8987c478bd9Sstevel@tonic-gate * via locking all constituent pages. 8997c478bd9Sstevel@tonic-gate * 9007c478bd9Sstevel@tonic-gate * Return NULL if p_szc is 0. 9017c478bd9Sstevel@tonic-gate * 9027c478bd9Sstevel@tonic-gate * It should only be used for pages that can be demoted by hat_page_demote() 9037c478bd9Sstevel@tonic-gate * i.e. non swapfs file system pages. The logic here is lifted from 9047c478bd9Sstevel@tonic-gate * sfmmu_mlspl_enter() except there's no need to worry about p_szc increase 9057c478bd9Sstevel@tonic-gate * since the page is locked and not free. 9067c478bd9Sstevel@tonic-gate * 9077c478bd9Sstevel@tonic-gate * Hash of the root page is used to find the lock. 9087c478bd9Sstevel@tonic-gate * To find the root in the presense of hat_page_demote() chageing the location 9097c478bd9Sstevel@tonic-gate * of the root this routine relies on the fact that hat_page_demote() changes 9107c478bd9Sstevel@tonic-gate * root last. 9117c478bd9Sstevel@tonic-gate * 9127c478bd9Sstevel@tonic-gate * If NULL is returned pp's p_szc is guaranteed to be 0. If non NULL is 9137c478bd9Sstevel@tonic-gate * returned pp's p_szc may be any value. 9147c478bd9Sstevel@tonic-gate */ 9157c478bd9Sstevel@tonic-gate kmutex_t * 9167c478bd9Sstevel@tonic-gate page_szc_lock(page_t *pp) 9177c478bd9Sstevel@tonic-gate { 9187c478bd9Sstevel@tonic-gate kmutex_t *mtx; 9197c478bd9Sstevel@tonic-gate page_t *rootpp; 9207c478bd9Sstevel@tonic-gate uint_t szc; 9217c478bd9Sstevel@tonic-gate uint_t rszc; 9227c478bd9Sstevel@tonic-gate uint_t pszc = pp->p_szc; 9237c478bd9Sstevel@tonic-gate 9247c478bd9Sstevel@tonic-gate ASSERT(pp != NULL); 9257c478bd9Sstevel@tonic-gate ASSERT(PAGE_LOCKED(pp)); 9267c478bd9Sstevel@tonic-gate ASSERT(!PP_ISFREE(pp)); 9277c478bd9Sstevel@tonic-gate ASSERT(pp->p_vnode != NULL); 9287c478bd9Sstevel@tonic-gate ASSERT(!IS_SWAPFSVP(pp->p_vnode)); 929ad23a2dbSjohansen ASSERT(!PP_ISKAS(pp)); 9307c478bd9Sstevel@tonic-gate 9317c478bd9Sstevel@tonic-gate again: 9327c478bd9Sstevel@tonic-gate if (pszc == 0) { 9337c478bd9Sstevel@tonic-gate VM_STAT_ADD(pszclck_stat[0]); 9347c478bd9Sstevel@tonic-gate return (NULL); 9357c478bd9Sstevel@tonic-gate } 9367c478bd9Sstevel@tonic-gate 9377c478bd9Sstevel@tonic-gate /* The lock lives in the root page */ 9387c478bd9Sstevel@tonic-gate 9397c478bd9Sstevel@tonic-gate rootpp = PP_GROUPLEADER(pp, pszc); 9407c478bd9Sstevel@tonic-gate mtx = PAGE_SZC_MUTEX(rootpp); 9417c478bd9Sstevel@tonic-gate mutex_enter(mtx); 9427c478bd9Sstevel@tonic-gate 9437c478bd9Sstevel@tonic-gate /* 9447c478bd9Sstevel@tonic-gate * since p_szc can only decrease if pp == rootpp 9457c478bd9Sstevel@tonic-gate * rootpp will be always the same i.e we have the right root 9467c478bd9Sstevel@tonic-gate * regardless of rootpp->p_szc. 9477c478bd9Sstevel@tonic-gate * If location of pp's root didn't change after we took 9487c478bd9Sstevel@tonic-gate * the lock we have the right root. return mutex hashed off it. 9497c478bd9Sstevel@tonic-gate */ 9507c478bd9Sstevel@tonic-gate if (pp == rootpp || (rszc = rootpp->p_szc) == pszc) { 9517c478bd9Sstevel@tonic-gate VM_STAT_ADD(pszclck_stat[1]); 9527c478bd9Sstevel@tonic-gate return (mtx); 9537c478bd9Sstevel@tonic-gate } 9547c478bd9Sstevel@tonic-gate 9557c478bd9Sstevel@tonic-gate /* 9567c478bd9Sstevel@tonic-gate * root location changed because page got demoted. 9577c478bd9Sstevel@tonic-gate * locate the new root. 9587c478bd9Sstevel@tonic-gate */ 9597c478bd9Sstevel@tonic-gate if (rszc < pszc) { 9607c478bd9Sstevel@tonic-gate szc = pp->p_szc; 9617c478bd9Sstevel@tonic-gate ASSERT(szc < pszc); 9627c478bd9Sstevel@tonic-gate mutex_exit(mtx); 9637c478bd9Sstevel@tonic-gate pszc = szc; 9647c478bd9Sstevel@tonic-gate VM_STAT_ADD(pszclck_stat[2]); 9657c478bd9Sstevel@tonic-gate goto again; 9667c478bd9Sstevel@tonic-gate } 9677c478bd9Sstevel@tonic-gate 9687c478bd9Sstevel@tonic-gate VM_STAT_ADD(pszclck_stat[3]); 9697c478bd9Sstevel@tonic-gate /* 9707c478bd9Sstevel@tonic-gate * current hat_page_demote not done yet. 9717c478bd9Sstevel@tonic-gate * wait for it to finish. 9727c478bd9Sstevel@tonic-gate */ 9737c478bd9Sstevel@tonic-gate mutex_exit(mtx); 9747c478bd9Sstevel@tonic-gate rootpp = PP_GROUPLEADER(rootpp, rszc); 9757c478bd9Sstevel@tonic-gate mtx = PAGE_SZC_MUTEX(rootpp); 9767c478bd9Sstevel@tonic-gate mutex_enter(mtx); 9777c478bd9Sstevel@tonic-gate mutex_exit(mtx); 9787c478bd9Sstevel@tonic-gate ASSERT(rootpp->p_szc < rszc); 9797c478bd9Sstevel@tonic-gate goto again; 9807c478bd9Sstevel@tonic-gate } 9817c478bd9Sstevel@tonic-gate 9827c478bd9Sstevel@tonic-gate int 9837c478bd9Sstevel@tonic-gate page_szc_lock_assert(page_t *pp) 9847c478bd9Sstevel@tonic-gate { 9857c478bd9Sstevel@tonic-gate page_t *rootpp = PP_PAGEROOT(pp); 9867c478bd9Sstevel@tonic-gate kmutex_t *mtx = PAGE_SZC_MUTEX(rootpp); 9877c478bd9Sstevel@tonic-gate 9887c478bd9Sstevel@tonic-gate return (MUTEX_HELD(mtx)); 9897c478bd9Sstevel@tonic-gate } 990ae115bc7Smrj 991ae115bc7Smrj /* 992ae115bc7Smrj * memseg locking 993ae115bc7Smrj */ 994ae115bc7Smrj static krwlock_t memsegslock; 995ae115bc7Smrj 996ae115bc7Smrj /* 997ae115bc7Smrj * memlist (phys_install, phys_avail) locking. 998ae115bc7Smrj */ 999ae115bc7Smrj static krwlock_t memlists_lock; 1000ae115bc7Smrj 1001ae115bc7Smrj void 1002ae115bc7Smrj memsegs_lock(int writer) 1003ae115bc7Smrj { 1004ae115bc7Smrj rw_enter(&memsegslock, writer ? RW_WRITER : RW_READER); 1005ae115bc7Smrj } 1006ae115bc7Smrj 1007ae115bc7Smrj /*ARGSUSED*/ 1008ae115bc7Smrj void 1009ae115bc7Smrj memsegs_unlock(int writer) 1010ae115bc7Smrj { 1011ae115bc7Smrj rw_exit(&memsegslock); 1012ae115bc7Smrj } 1013ae115bc7Smrj 1014ae115bc7Smrj int 1015ae115bc7Smrj memsegs_lock_held(void) 1016ae115bc7Smrj { 1017ae115bc7Smrj return (RW_LOCK_HELD(&memsegslock)); 1018ae115bc7Smrj } 1019ae115bc7Smrj 1020ae115bc7Smrj void 1021ae115bc7Smrj memlist_read_lock(void) 1022ae115bc7Smrj { 1023ae115bc7Smrj rw_enter(&memlists_lock, RW_READER); 1024ae115bc7Smrj } 1025ae115bc7Smrj 1026ae115bc7Smrj void 1027ae115bc7Smrj memlist_read_unlock(void) 1028ae115bc7Smrj { 1029ae115bc7Smrj rw_exit(&memlists_lock); 1030ae115bc7Smrj } 1031ae115bc7Smrj 1032ae115bc7Smrj void 1033ae115bc7Smrj memlist_write_lock(void) 1034ae115bc7Smrj { 1035ae115bc7Smrj rw_enter(&memlists_lock, RW_WRITER); 1036ae115bc7Smrj } 1037ae115bc7Smrj 1038ae115bc7Smrj void 1039ae115bc7Smrj memlist_write_unlock(void) 1040ae115bc7Smrj { 1041ae115bc7Smrj rw_exit(&memlists_lock); 1042ae115bc7Smrj } 1043