xref: /illumos-gate/usr/src/uts/common/sys/swap.h (revision b4203d75)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 /*
22  * Copyright 2014 Garrett D'Amore <garrett@damore.org>
23  * Copyright (c) 1987, 2010, Oracle and/or its affiliates. All rights reserved.
24  */
25 
26 /*	Copyright (c) 1983, 1984, 1985, 1986, 1987, 1988, 1989 AT&T	*/
27 /*	  All Rights Reserved	*/
28 
29 /*
30  * University Copyright- Copyright (c) 1982, 1986, 1988
31  * The Regents of the University of California
32  * All Rights Reserved
33  *
34  * University Acknowledgment- Portions of this document are derived from
35  * software developed by the University of California, Berkeley, and its
36  * contributors.
37  */
38 
39 #ifndef	_SYS_SWAP_H
40 #define	_SYS_SWAP_H
41 
42 #include <sys/isa_defs.h>
43 #include <sys/feature_tests.h>
44 #include <vm/anon.h>
45 #include <sys/fs/swapnode.h>
46 
47 #ifdef	__cplusplus
48 extern "C" {
49 #endif
50 
51 #if !defined(_LP64) && _FILE_OFFSET_BITS == 64
52 #error  "Cannot use swapctl in the large files compilation environment"
53 #endif
54 
55 /* The following are for the swapctl system call */
56 
57 #define	SC_ADD		1	/* add a specified resource for swapping */
58 #define	SC_LIST		2	/* list all the swapping resources */
59 #define	SC_REMOVE	3	/* remove the specified swapping resource */
60 #define	SC_GETNSWP	4	/* get number of swap resources configured */
61 #define	SC_AINFO	5	/* get anonymous memory resource information */
62 
63 typedef struct swapres {
64 	char	*sr_name;	/* pathname of the resource specified */
65 	off_t	sr_start;	/* starting offset of the swapping resource */
66 	off_t 	sr_length;	/* length of the swap area */
67 } swapres_t;
68 
69 typedef struct swapent {
70 	char 	*ste_path;	/* get the name of the swap file */
71 	off_t	ste_start;	/* starting block for swapping */
72 	off_t	ste_length;	/* length of swap area */
73 	long	ste_pages;	/* numbers of pages for swapping */
74 	long	ste_free;	/* numbers of ste_pages free */
75 	int	ste_flags;	/* see below */
76 } swapent_t;
77 
78 typedef struct swaptable {
79 	int	swt_n;			/* number of swapents following */
80 	struct	swapent	swt_ent[1];	/* array of swt_n swapents */
81 } swaptbl_t;
82 
83 
84 #if defined(_SYSCALL32)
85 
86 /* Kernel's view of user ILP32 swapres and swapent structures */
87 
88 typedef struct swapres32 {
89 	caddr32_t sr_name;	/* pathname of the resource specified */
90 	off32_t	sr_start;	/* starting offset of the swapping resource */
91 	off32_t	sr_length;	/* length of the swap area */
92 } swapres32_t;
93 
94 typedef struct swapent32 {
95 	caddr32_t ste_path;	/* get the name of the swap file */
96 	off32_t	ste_start;	/* starting block for swapping */
97 	off32_t	ste_length;	/* length of swap area */
98 	int32_t	ste_pages;	/* numbers of pages for swapping */
99 	int32_t	ste_free;	/* numbers of ste_pages free */
100 	int32_t	ste_flags;	/* see below */
101 } swapent32_t;
102 
103 typedef struct	swaptable32 {
104 	int32_t	swt_n;			/* number of swapents following */
105 	struct	swapent32 swt_ent[1];	/* array of swt_n swapents */
106 } swaptbl32_t;
107 
108 #endif	/* _SYSCALL32 */
109 
110 #if defined(_KERNEL)
111 extern int swapctl(int, void *, int *);
112 #if defined(_LP64) && defined(_SYSCALL32)
113 extern int swapctl32(int, void *, int *);
114 #endif /* _LP64 && _SYSCALL32 */
115 #else /* !_KERNEL */
116 extern int swapctl(int, void *);
117 #endif /* _KERNEL */
118 
119 
120 /* ste_flags values */
121 
122 #define	ST_INDEL	0x01		/* Deletion of file is in progress. */
123 					/* Prevents others from deleting or */
124 					/* allocating from it */
125 #define	ST_DOINGDEL	0x02		/* Set during deletion of file */
126 					/* Clearing during deletion signals */
127 					/* that you want to add the file back */
128 					/* again, and will eventually cause */
129 					/* it to be added back */
130 
131 /*
132  * VM - virtual swap device.
133  */
134 struct	swapinfo {
135 	ulong_t si_soff;		/* starting offset (bytes) of file */
136 	ulong_t si_eoff;		/* ending offset (bytes) of file */
137 	struct	vnode *si_vp;		/* vnode (commonvp if device) */
138 	struct	swapinfo *si_next;	/* next swap area */
139 	int	si_allocs;		/* # of conseq. allocs from this area */
140 	short	si_flags;		/* flags defined below */
141 	pgcnt_t	si_npgs;		/* number of pages of swap space */
142 	pgcnt_t	si_nfpgs;		/* number of free pages of swap space */
143 	int 	si_pnamelen;		/* swap file name length + 1 */
144 	char 	*si_pname;		/* swap file name */
145 	ssize_t	si_mapsize;		/* # bytes allocated for bitmap */
146 	uint_t 	*si_swapslots;		/* bitmap of slots, unset == free */
147 	pgcnt_t	si_hint;		/* first page to check if free */
148 	ssize_t	si_checkcnt;		/* # of checks to find freeslot */
149 	ssize_t	si_alloccnt;		/* used to find ave checks */
150 };
151 
152 /*
153  * Stuff to convert an anon slot pointer to a page name.
154  * Because the address of the slot (ap) is a unique identifier, we
155  * use it to generate a unique (vp,off), as shown in the comment for
156  * swap_alloc().
157  *
158  * The off bits are shifted PAGESHIFT to directly form a page aligned
159  * offset; the vp index bits map 1-1 to a vnode.
160  *
161  */
162 #define	MAX_SWAP_VNODES_LOG2	11		/* log2(MAX_SWAP_VNODES) */
163 #define	MAX_SWAP_VNODES	(1U << MAX_SWAP_VNODES_LOG2)	/* max # swap vnodes */
164 #define	AN_VPMASK	(MAX_SWAP_VNODES - 1)	/* vp index mask */
165 #define	AN_VPSHIFT	MAX_SWAP_VNODES_LOG2
166 /*
167  * Convert from an anon slot to associated vnode and offset.
168  */
169 #define	swap_xlate(AP, VPP, OFFP)					\
170 {									\
171 	*(VPP) = (AP)->an_vp;						\
172 	*(OFFP) = (AP)->an_off;						\
173 }
174 #define	swap_xlate_nopanic	swap_xlate
175 
176 /*
177  * Get a vnode name for an anon slot.
178  * The vnum, offset are derived from anon struct address which is
179  * 16 bytes aligned.  anon structs may be kmem_cache_alloc'd concurrently by
180  * multiple threads and come from a small range of addresses (same slab), in
181  * which case high order AP bits do not vary much, so choose vnum from low
182  * order bits which vary the most.  Different threads will thus get different
183  * vnums and vnodes, which avoids vph_mutex_contention on the subsequent
184  * page_hashin().
185  *
186  * +-----------...-------------------+-----------------------+----+
187  * |        swap offset              |           vnum        |0000|
188  * +-----------...-------------------+-----------------------+----+
189  *  63                             15 14                    4 3   0
190  */
191 #define	swap_alloc(AP)							\
192 {									\
193 	(AP)->an_vp = swapfs_getvp(((uintptr_t)(AP) >> AN_CACHE_ALIGN_LOG2) \
194 	    & AN_VPMASK); 						\
195 	(AP)->an_off = (anoff_t)((((uintptr_t)(AP)) >>			\
196 	    AN_VPSHIFT + AN_CACHE_ALIGN_LOG2) << PAGESHIFT);		\
197 }
198 
199 /*
200  * Free the page name for the specified anon slot.
201  * For now there's nothing to do.
202  */
203 #define	swap_free(AP)
204 
205 /* Flags for swap_phys_alloc */
206 #define	SA_NOT 	0x01 	/* Must have slot from swap dev other than input one */
207 
208 /* Special error codes for swap_newphysname() */
209 #define	SE_NOSWAP	-1	/* No physical swap slots available */
210 #define	SE_NOANON	-2	/* No anon slot for swap slot */
211 
212 #ifdef _KERNEL
213 extern struct anon *swap_anon(struct vnode *vp, u_offset_t off);
214 extern int swap_phys_alloc(struct vnode **vpp, u_offset_t *offp, size_t *lenp,
215     uint_t flags);
216 extern void swap_phys_free(struct vnode *vp, u_offset_t off, size_t len);
217 extern int swap_getphysname(struct vnode *vp, u_offset_t off,
218     struct vnode **pvpp, u_offset_t *poffp);
219 extern int swap_newphysname(struct vnode *vp, u_offset_t offset,
220     u_offset_t *offp, size_t *lenp, struct vnode **pvpp, u_offset_t *poffp);
221 
222 extern struct swapinfo *swapinfo;
223 extern int swap_debug;
224 #endif	/* _KERNEL */
225 
226 #ifdef SWAP_DEBUG
227 #define	SW_RENAME	0x01
228 #define	SW_RESV		0x02
229 #define	SW_ALLOC	0x04
230 #define	SW_CTL		0x08
231 #define	SWAP_PRINT(f, s, x1, x2, x3, x4, x5) \
232 		if (swap_debug & f) \
233 			printf(s, x1, x2, x3, x4, x5);
234 #else	/* SWAP_DEBUG */
235 #define	SWAP_PRINT(f, s, x1, x2, x3, x4, x5)
236 #endif	/* SWAP_DEBUG */
237 
238 #ifdef	__cplusplus
239 }
240 #endif
241 
242 #endif	/* _SYS_SWAP_H */
243