| kern_sx.c (196772) | kern_sx.c (197643) |
|---|---|
| 1/*- 2 * Copyright (c) 2007 Attilio Rao <attilio@freebsd.org> 3 * Copyright (c) 2001 Jason Evans <jasone@freebsd.org> 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: --- 27 unchanged lines hidden (view full) --- 36 * so should not be relied upon in combination with sx locks. 37 */ 38 39#include "opt_ddb.h" 40#include "opt_kdtrace.h" 41#include "opt_no_adaptive_sx.h" 42 43#include <sys/cdefs.h> | 1/*- 2 * Copyright (c) 2007 Attilio Rao <attilio@freebsd.org> 3 * Copyright (c) 2001 Jason Evans <jasone@freebsd.org> 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: --- 27 unchanged lines hidden (view full) --- 36 * so should not be relied upon in combination with sx locks. 37 */ 38 39#include "opt_ddb.h" 40#include "opt_kdtrace.h" 41#include "opt_no_adaptive_sx.h" 42 43#include <sys/cdefs.h> |
| 44__FBSDID("$FreeBSD: head/sys/kern/kern_sx.c 196772 2009-09-02 17:33:51Z attilio $"); | 44__FBSDID("$FreeBSD: head/sys/kern/kern_sx.c 197643 2009-09-30 13:26:31Z attilio $"); |
| 45 46#include <sys/param.h> 47#include <sys/ktr.h> 48#include <sys/linker_set.h> 49#include <sys/lock.h> 50#include <sys/mutex.h> 51#include <sys/proc.h> 52#include <sys/sleepqueue.h> --- 873 unchanged lines hidden (view full) --- 926 KASSERT(!(x & SX_LOCK_SHARED_WAITERS), 927 ("%s: waiting sharers", __func__)); 928 929 /* 930 * See if there is more than one shared lock held. If 931 * so, just drop one and return. 932 */ 933 if (SX_SHARERS(x) > 1) { | 45 46#include <sys/param.h> 47#include <sys/ktr.h> 48#include <sys/linker_set.h> 49#include <sys/lock.h> 50#include <sys/mutex.h> 51#include <sys/proc.h> 52#include <sys/sleepqueue.h> --- 873 unchanged lines hidden (view full) --- 926 KASSERT(!(x & SX_LOCK_SHARED_WAITERS), 927 ("%s: waiting sharers", __func__)); 928 929 /* 930 * See if there is more than one shared lock held. If 931 * so, just drop one and return. 932 */ 933 if (SX_SHARERS(x) > 1) { |
| 934 if (atomic_cmpset_ptr(&sx->sx_lock, x, | 934 if (atomic_cmpset_rel_ptr(&sx->sx_lock, x, |
| 935 x - SX_ONE_SHARER)) { 936 if (LOCK_LOG_TEST(&sx->lock_object, 0)) 937 CTR4(KTR_LOCK, 938 "%s: %p succeeded %p -> %p", 939 __func__, sx, (void *)x, 940 (void *)(x - SX_ONE_SHARER)); 941 break; 942 } 943 continue; 944 } 945 946 /* 947 * If there aren't any waiters for an exclusive lock, 948 * then try to drop it quickly. 949 */ 950 if (!(x & SX_LOCK_EXCLUSIVE_WAITERS)) { 951 MPASS(x == SX_SHARERS_LOCK(1)); | 935 x - SX_ONE_SHARER)) { 936 if (LOCK_LOG_TEST(&sx->lock_object, 0)) 937 CTR4(KTR_LOCK, 938 "%s: %p succeeded %p -> %p", 939 __func__, sx, (void *)x, 940 (void *)(x - SX_ONE_SHARER)); 941 break; 942 } 943 continue; 944 } 945 946 /* 947 * If there aren't any waiters for an exclusive lock, 948 * then try to drop it quickly. 949 */ 950 if (!(x & SX_LOCK_EXCLUSIVE_WAITERS)) { 951 MPASS(x == SX_SHARERS_LOCK(1)); |
| 952 if (atomic_cmpset_ptr(&sx->sx_lock, SX_SHARERS_LOCK(1), 953 SX_LOCK_UNLOCKED)) { | 952 if (atomic_cmpset_rel_ptr(&sx->sx_lock, 953 SX_SHARERS_LOCK(1), SX_LOCK_UNLOCKED)) { |
| 954 if (LOCK_LOG_TEST(&sx->lock_object, 0)) 955 CTR2(KTR_LOCK, "%s: %p last succeeded", 956 __func__, sx); 957 break; 958 } 959 continue; 960 } 961 --- 6 unchanged lines hidden (view full) --- 968 sleepq_lock(&sx->lock_object); 969 970 /* 971 * Wake up semantic here is quite simple: 972 * Just wake up all the exclusive waiters. 973 * Note that the state of the lock could have changed, 974 * so if it fails loop back and retry. 975 */ | 954 if (LOCK_LOG_TEST(&sx->lock_object, 0)) 955 CTR2(KTR_LOCK, "%s: %p last succeeded", 956 __func__, sx); 957 break; 958 } 959 continue; 960 } 961 --- 6 unchanged lines hidden (view full) --- 968 sleepq_lock(&sx->lock_object); 969 970 /* 971 * Wake up semantic here is quite simple: 972 * Just wake up all the exclusive waiters. 973 * Note that the state of the lock could have changed, 974 * so if it fails loop back and retry. 975 */ |
| 976 if (!atomic_cmpset_ptr(&sx->sx_lock, | 976 if (!atomic_cmpset_rel_ptr(&sx->sx_lock, |
| 977 SX_SHARERS_LOCK(1) | SX_LOCK_EXCLUSIVE_WAITERS, 978 SX_LOCK_UNLOCKED)) { 979 sleepq_release(&sx->lock_object); 980 continue; 981 } 982 if (LOCK_LOG_TEST(&sx->lock_object, 0)) 983 CTR2(KTR_LOCK, "%s: %p waking up all thread on" 984 "exclusive queue", __func__, sx); --- 174 unchanged lines hidden --- | 977 SX_SHARERS_LOCK(1) | SX_LOCK_EXCLUSIVE_WAITERS, 978 SX_LOCK_UNLOCKED)) { 979 sleepq_release(&sx->lock_object); 980 continue; 981 } 982 if (LOCK_LOG_TEST(&sx->lock_object, 0)) 983 CTR2(KTR_LOCK, "%s: %p waking up all thread on" 984 "exclusive queue", __func__, sx); --- 174 unchanged lines hidden --- |