FreeBSD/Linux Kernel Cross Reference
sys/sys/sf_buf.h
1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 2014 Gleb Smirnoff <glebius@FreeBSD.org>
5 * Copyright (c) 2003-2004 Alan L. Cox <alc@cs.rice.edu>
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 *
29 * $FreeBSD$
30 */
31
32 #ifndef _SYS_SF_BUF_H_
33 #define _SYS_SF_BUF_H_
34
35 struct sfstat { /* sendfile statistics */
36 uint64_t sf_syscalls; /* times sendfile was called */
37 uint64_t sf_noiocnt; /* times sendfile didn't require I/O */
38 uint64_t sf_iocnt; /* times sendfile had to do disk I/O */
39 uint64_t sf_pages_read; /* pages read as part of a request */
40 uint64_t sf_pages_valid; /* pages were valid for a request */
41 uint64_t sf_rhpages_requested; /* readahead pages requested */
42 uint64_t sf_rhpages_read; /* readahead pages read */
43 uint64_t sf_busy; /* times aborted on a busy page */
44 uint64_t sf_allocfail; /* times sfbuf allocation failed */
45 uint64_t sf_allocwait; /* times sfbuf allocation had to wait */
46 uint64_t sf_pages_bogus; /* times bogus page was used */
47 };
48
49 #ifdef _KERNEL
50 #include <sys/types.h>
51 #include <sys/systm.h>
52 #include <sys/counter.h>
53 #include <vm/vm.h>
54 #include <vm/vm_param.h>
55 #include <vm/vm_page.h>
56
57 /*
58 * Sf_bufs, or sendfile(2) buffers provide a vm_page that is mapped
59 * into kernel address space. Note, that they aren't used only
60 * by sendfile(2)!
61 *
62 * Sf_bufs could be implemented as a feature of vm_page_t, but that
63 * would require growth of the structure. That's why they are implemented
64 * as a separate hash indexed by vm_page address. Implementation lives in
65 * kern/subr_sfbuf.c. Meanwhile, most 64-bit machines have a physical map,
66 * so they don't require this hash at all, thus ignore subr_sfbuf.c.
67 *
68 * Different 32-bit architectures demand different requirements on sf_buf
69 * hash and functions. They request features in machine/vmparam.h, which
70 * enable parts of this file. They can also optionally provide helpers in
71 * machine/sf_buf.h
72 *
73 * Defines are:
74 * SFBUF This machine requires sf_buf hash.
75 * subr_sfbuf.c should be compiled.
76 * SFBUF_CPUSET This machine can perform SFB_CPUPRIVATE mappings,
77 * that do no invalidate cache on the rest of CPUs.
78 * SFBUF_NOMD This machine doesn't have machine/sf_buf.h
79 *
80 * SFBUF_MAP This machine provides its own sf_buf_map() and
81 * sf_buf_unmap().
82 * SFBUF_PROCESS_PAGE This machine provides sf_buf_process_page()
83 * function.
84 */
85
86 #ifdef SFBUF
87 #if defined(SMP) && defined(SFBUF_CPUSET)
88 #include <sys/_cpuset.h>
89 #endif
90 #include <sys/queue.h>
91
92 struct sf_buf {
93 LIST_ENTRY(sf_buf) list_entry; /* list of buffers */
94 TAILQ_ENTRY(sf_buf) free_entry; /* list of buffers */
95 vm_page_t m; /* currently mapped page */
96 vm_offset_t kva; /* va of mapping */
97 int ref_count; /* usage of this mapping */
98 #if defined(SMP) && defined(SFBUF_CPUSET)
99 cpuset_t cpumask; /* where mapping is valid */
100 #endif
101 };
102 #else /* ! SFBUF */
103 struct sf_buf;
104 #endif /* SFBUF */
105
106 #ifndef SFBUF_NOMD
107 #include <machine/sf_buf.h>
108 #endif
109
110 #ifdef SFBUF
111 struct sf_buf *sf_buf_alloc(struct vm_page *, int);
112 void sf_buf_free(struct sf_buf *);
113 void sf_buf_ref(struct sf_buf *);
114
115 static inline vm_offset_t
116 sf_buf_kva(struct sf_buf *sf)
117 {
118 if (PMAP_HAS_DMAP)
119 return (PHYS_TO_DMAP(VM_PAGE_TO_PHYS((vm_page_t)sf)));
120
121 return (sf->kva);
122 }
123
124 static inline vm_page_t
125 sf_buf_page(struct sf_buf *sf)
126 {
127 if (PMAP_HAS_DMAP)
128 return ((vm_page_t)sf);
129
130 return (sf->m);
131 }
132
133 #ifndef SFBUF_MAP
134 #include <vm/pmap.h>
135
136 static inline void
137 sf_buf_map(struct sf_buf *sf, int flags)
138 {
139
140 pmap_qenter(sf->kva, &sf->m, 1);
141 }
142
143 static inline int
144 sf_buf_unmap(struct sf_buf *sf)
145 {
146
147 return (0);
148 }
149 #endif /* SFBUF_MAP */
150
151 #if defined(SMP) && defined(SFBUF_CPUSET)
152 void sf_buf_shootdown(struct sf_buf *, int);
153 #endif
154
155 #ifdef SFBUF_PROCESS_PAGE
156 boolean_t sf_buf_process_page(vm_page_t, void (*)(struct sf_buf *));
157 #endif
158
159 #else /* ! SFBUF */
160
161 static inline struct sf_buf *
162 sf_buf_alloc(struct vm_page *m, int pri)
163 {
164
165 return ((struct sf_buf *)m);
166 }
167
168 static inline void
169 sf_buf_free(struct sf_buf *sf)
170 {
171 }
172
173 static inline void
174 sf_buf_ref(struct sf_buf *sf)
175 {
176 }
177 #endif /* SFBUF */
178
179 /*
180 * Options to sf_buf_alloc() are specified through its flags argument. This
181 * argument's value should be the result of a bitwise or'ing of one or more
182 * of the following values.
183 */
184 #define SFB_CATCH 1 /* Check signals if the allocation
185 sleeps. */
186 #define SFB_CPUPRIVATE 2 /* Create a CPU private mapping. */
187 #define SFB_DEFAULT 0
188 #define SFB_NOWAIT 4 /* Return NULL if all bufs are used. */
189
190 extern counter_u64_t sfstat[sizeof(struct sfstat) / sizeof(uint64_t)];
191 #define SFSTAT_ADD(name, val) \
192 counter_u64_add(sfstat[offsetof(struct sfstat, name) / sizeof(uint64_t)],\
193 (val))
194 #define SFSTAT_INC(name) SFSTAT_ADD(name, 1)
195 #endif /* _KERNEL */
196 #endif /* !_SYS_SF_BUF_H_ */
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