1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright (c) 2018, Matthew Macy <mmacy@freebsd.org> 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: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25 * SUCH DAMAGE. 26 * 27 * $FreeBSD$ 28 */ 29 30 #ifndef _SYS_EPOCH_H_ 31 #define _SYS_EPOCH_H_ 32 #ifdef _KERNEL 33 #include <sys/lock.h> 34 #include <sys/proc.h> 35 #endif 36 37 struct thread; 38 struct epoch; 39 typedef struct epoch *epoch_t; 40 41 #define EPOCH_PREEMPT 0x1 42 43 extern epoch_t global_epoch; 44 extern epoch_t global_epoch_preempt; 45 46 struct epoch_context { 47 void *data[2]; 48 } __aligned(sizeof(void *)); 49 50 typedef struct epoch_context *epoch_context_t; 51 52 epoch_t epoch_alloc(int flags); 53 void epoch_free(epoch_t epoch); 54 void epoch_enter(epoch_t epoch); 55 void epoch_enter_preempt_internal(epoch_t epoch, struct thread *td); 56 void epoch_exit(epoch_t epoch); 57 void epoch_exit_preempt_internal(epoch_t epoch, struct thread *td); 58 void epoch_wait(epoch_t epoch); 59 void epoch_wait_preempt(epoch_t epoch); 60 void epoch_call(epoch_t epoch, epoch_context_t ctx, void (*callback) (epoch_context_t)); 61 int in_epoch(void); 62 63 #ifdef _KERNEL 64 DPCPU_DECLARE(int, epoch_cb_count); 65 DPCPU_DECLARE(struct grouptask, epoch_cb_task); 66 67 static __inline void 68 epoch_enter_preempt(epoch_t epoch) 69 { 70 struct thread *td; 71 int nesting __unused; 72 73 td = curthread; 74 nesting = td->td_epochnest++; 75 #ifndef INVARIANTS 76 if (nesting == 0) 77 #endif 78 epoch_enter_preempt_internal(epoch, td); 79 } 80 81 static __inline void 82 epoch_exit_preempt(epoch_t epoch) 83 { 84 struct thread *td; 85 86 td = curthread; 87 MPASS(td->td_epochnest); 88 if (td->td_epochnest-- == 1) 89 epoch_exit_preempt_internal(epoch, td); 90 } 91 #endif /* _KERNEL */ 92 #endif 93