| kern_rwlock.c (176017) | kern_rwlock.c (176076) |
|---|---|
| 1/*- 2 * Copyright (c) 2006 John Baldwin <jhb@FreeBSD.org> 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright --- 18 unchanged lines hidden (view full) --- 27 * SUCH DAMAGE. 28 */ 29 30/* 31 * Machine independent bits of reader/writer lock implementation. 32 */ 33 34#include <sys/cdefs.h> | 1/*- 2 * Copyright (c) 2006 John Baldwin <jhb@FreeBSD.org> 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright --- 18 unchanged lines hidden (view full) --- 27 * SUCH DAMAGE. 28 */ 29 30/* 31 * Machine independent bits of reader/writer lock implementation. 32 */ 33 34#include <sys/cdefs.h> |
| 35__FBSDID("$FreeBSD: head/sys/kern/kern_rwlock.c 176017 2008-02-06 01:02:13Z jeff $"); | 35__FBSDID("$FreeBSD: head/sys/kern/kern_rwlock.c 176076 2008-02-07 06:16:54Z jeff $"); |
| 36 37#include "opt_ddb.h" 38#include "opt_no_adaptive_rwlocks.h" 39 40#include <sys/param.h> 41#include <sys/ktr.h> 42#include <sys/lock.h> 43#include <sys/mutex.h> --- 630 unchanged lines hidden (view full) --- 674 * In the case of both readers and writers waiting we wakeup the 675 * readers but leave the RW_LOCK_WRITE_WAITERS flag set. If a 676 * new writer comes in before a reader it will claim the lock up 677 * above. There is probably a potential priority inversion in 678 * there that could be worked around either by waking both queues 679 * of waiters or doing some complicated lock handoff gymnastics. 680 */ 681 v = RW_UNLOCKED; | 36 37#include "opt_ddb.h" 38#include "opt_no_adaptive_rwlocks.h" 39 40#include <sys/param.h> 41#include <sys/ktr.h> 42#include <sys/lock.h> 43#include <sys/mutex.h> --- 630 unchanged lines hidden (view full) --- 674 * In the case of both readers and writers waiting we wakeup the 675 * readers but leave the RW_LOCK_WRITE_WAITERS flag set. If a 676 * new writer comes in before a reader it will claim the lock up 677 * above. There is probably a potential priority inversion in 678 * there that could be worked around either by waking both queues 679 * of waiters or doing some complicated lock handoff gymnastics. 680 */ 681 v = RW_UNLOCKED; |
| 682 if (rw->rw_lock & RW_LOCK_READ_WAITERS) { 683 queue = TS_SHARED_QUEUE; 684 v |= (rw->rw_lock & RW_LOCK_WRITE_WAITERS); 685 } else | 682 if (rw->rw_lock & RW_LOCK_WRITE_WAITERS) { |
| 686 queue = TS_EXCLUSIVE_QUEUE; | 683 queue = TS_EXCLUSIVE_QUEUE; |
| 684 v |= (rw->rw_lock & RW_LOCK_READ_WAITERS); 685 } else 686 queue = TS_SHARED_QUEUE; |
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| 687 688 /* Wake up all waiters for the specific queue. */ 689 if (LOCK_LOG_TEST(&rw->lock_object, 0)) 690 CTR3(KTR_LOCK, "%s: %p waking up %s waiters", __func__, rw, 691 queue == TS_SHARED_QUEUE ? "read" : "write"); 692 turnstile_broadcast(ts, queue); 693 atomic_store_rel_ptr(&rw->rw_lock, v); 694 turnstile_unpend(ts, TS_EXCLUSIVE_LOCK); --- 262 unchanged lines hidden --- | 687 688 /* Wake up all waiters for the specific queue. */ 689 if (LOCK_LOG_TEST(&rw->lock_object, 0)) 690 CTR3(KTR_LOCK, "%s: %p waking up %s waiters", __func__, rw, 691 queue == TS_SHARED_QUEUE ? "read" : "write"); 692 turnstile_broadcast(ts, queue); 693 atomic_store_rel_ptr(&rw->rw_lock, v); 694 turnstile_unpend(ts, TS_EXCLUSIVE_LOCK); --- 262 unchanged lines hidden --- |