include/sys/swap.h

   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 /* The following are for the swapctl system call */
  52
  53 #define SC_ADD          1       /* add a specified resource for swapping */
  54 #define SC_LIST         2       /* list all the swapping resources */
  55 #define SC_REMOVE       3       /* remove the specified swapping resource */
  56 #define SC_GETNSWP      4       /* get number of swap resources configured */
  57 #define SC_AINFO        5       /* get anonymous memory resource information */
  58
  59 typedef struct swapres {
  60         char    *sr_name;       /* pathname of the resource specified */
  61         off_t   sr_start;       /* starting offset of the swapping resource */
  62         off_t   sr_length;      /* length of the swap area */
  63 } swapres_t;
  64
  65 typedef struct swapent {
  66         char    *ste_path;      /* get the name of the swap file */
  67         off_t   ste_start;      /* starting block for swapping */
  68         off_t   ste_length;     /* length of swap area */
  69         long    ste_pages;      /* numbers of pages for swapping */
  70         long    ste_free;       /* numbers of ste_pages free */
  71         int     ste_flags;      /* see below */
  72 } swapent_t;
  73
  74 typedef struct swaptable {
  75         int     swt_n;                  /* number of swapents following */
  76         struct  swapent swt_ent[1];     /* array of swt_n swapents */
  77 } swaptbl_t;
  78
  79
  80 #if defined(_SYSCALL32)
  81
  82 /* Kernel's view of user ILP32 swapres and swapent structures */
  83
  84 typedef struct swapres32 {
  85         caddr32_t sr_name;      /* pathname of the resource specified */
  86         off_t   sr_start;       /* starting offset of the swapping resource */
  87         off_t   sr_length;      /* length of the swap area */
  88 } swapres32_t;
  89
  90 typedef struct swapent32 {
  91         caddr32_t ste_path;     /* get the name of the swap file */
  92         off_t   ste_start;      /* starting block for swapping */
  93         off_t   ste_length;     /* length of swap area */
  94         int32_t ste_pages;      /* numbers of pages for swapping */
  95         int32_t ste_free;       /* numbers of ste_pages free */
  96         int32_t ste_flags;      /* see below */
  97 } swapent32_t;
  98
  99 typedef struct  swaptable32 {
 100         int32_t swt_n;                  /* number of swapents following */
 101         struct  swapent32 swt_ent[1];   /* array of swt_n swapents */
 102 } swaptbl32_t;
 103
 104 #endif  /* _SYSCALL32 */
 105
 106 #if defined(_KERNEL)
 107 extern int swapctl(int, void *, int *);
 108 #if defined(_LP64) && defined(_SYSCALL32)
 109 extern int swapctl32(int, void *, int *);
 110 #endif /* _LP64 && _SYSCALL32 */
 111 #else /* !_KERNEL */
 112 extern int swapctl(int, void *);
 113 #endif /* _KERNEL */
 114
 115
 116 /* ste_flags values */
 117
 118 #define ST_INDEL        0x01            /* Deletion of file is in progress. */
 119                                         /* Prevents others from deleting or */
 120                                         /* allocating from it */
 121 #define ST_DOINGDEL     0x02            /* Set during deletion of file */
 122                                         /* Clearing during deletion signals */
 123                                         /* that you want to add the file back */
 124                                         /* again, and will eventually cause */
 125                                         /* it to be added back */
 126
 127 /*
 128  * VM - virtual swap device.
 129  */
 130 struct  swapinfo {
 131         ulong_t si_soff;                /* starting offset (bytes) of file */
 132         ulong_t si_eoff;                /* ending offset (bytes) of file */
 133         struct  vnode *si_vp;           /* vnode (commonvp if device) */
 134         struct  swapinfo *si_next;      /* next swap area */
 135         int     si_allocs;              /* # of conseq. allocs from this area */
 136         short   si_flags;               /* flags defined below */
 137         pgcnt_t si_npgs;                /* number of pages of swap space */
 138         pgcnt_t si_nfpgs;               /* number of free pages of swap space */
 139         int     si_pnamelen;            /* swap file name length + 1 */
 140         char    *si_pname;              /* swap file name */
 141         ssize_t si_mapsize;             /* # bytes allocated for bitmap */
 142         uint_t  *si_swapslots;          /* bitmap of slots, unset == free */
 143         pgcnt_t si_hint;                /* first page to check if free */
 144         ssize_t si_checkcnt;            /* # of checks to find freeslot */
 145         ssize_t si_alloccnt;            /* used to find ave checks */
 146 };
 147
 148 /*
 149  * Stuff to convert an anon slot pointer to a page name.
 150  * Because the address of the slot (ap) is a unique identifier, we
 151  * use it to generate a unique (vp,off), as shown in the comment for
 152  * swap_alloc().
 153  *
 154  * The off bits are shifted PAGESHIFT to directly form a page aligned
 155  * offset; the vp index bits map 1-1 to a vnode.
 156  *
 157  */
 158 #define MAX_SWAP_VNODES_LOG2    11              /* log2(MAX_SWAP_VNODES) */
 159 #define MAX_SWAP_VNODES (1U << MAX_SWAP_VNODES_LOG2)    /* max # swap vnodes */
 160 #define AN_VPMASK       (MAX_SWAP_VNODES - 1)   /* vp index mask */
 161 #define AN_VPSHIFT      MAX_SWAP_VNODES_LOG2
 162 /*
 163  * Convert from an anon slot to associated vnode and offset.
 164  */
 165 #define swap_xlate(AP, VPP, OFFP)                                       \
 166 {                                                                       \
 167         *(VPP) = (AP)->an_vp;                                           \
 168         *(OFFP) = (AP)->an_off;                                         \
 169 }
 170 #define swap_xlate_nopanic      swap_xlate
 171
 172 /*
 173  * Get a vnode name for an anon slot.
 174  * The vnum, offset are derived from anon struct address which is
 175  * 16 bytes aligned.  anon structs may be kmem_cache_alloc'd concurrently by
 176  * multiple threads and come from a small range of addresses (same slab), in
 177  * which case high order AP bits do not vary much, so choose vnum from low
 178  * order bits which vary the most.  Different threads will thus get different
 179  * vnums and vnodes, which avoids contention on the subsequent
 180  * page_hashin().
 181  *
 182  * +-----------...-------------------+-----------------------+----+
 183  * |        swap offset              |           vnum        |0000|
 184  * +-----------...-------------------+-----------------------+----+
 185  *  63                             15 14                    4 3   0
 186  */
 187 #define swap_alloc(AP)                                                  \
 188 {                                                                       \
 189         (AP)->an_vp = swapfs_getvp(((uintptr_t)(AP) >> AN_CACHE_ALIGN_LOG2) \
 190             & AN_VPMASK);                                               \
 191         (AP)->an_off = (anoff_t)((((uintptr_t)(AP)) >>                  \
 192             AN_VPSHIFT + AN_CACHE_ALIGN_LOG2) << PAGESHIFT);            \
 193 }
 194
 195 /*
 196  * Free the page name for the specified anon slot.
 197  * For now there's nothing to do.
 198  */
 199 #define swap_free(AP)
 200
 201 /* Flags for swap_phys_alloc */
 202 #define SA_NOT  0x01    /* Must have slot from swap dev other than input one */
 203
 204 /* Special error codes for swap_newphysname() */
 205 #define SE_NOSWAP       -1      /* No physical swap slots available */
 206 #define SE_NOANON       -2      /* No anon slot for swap slot */
 207
 208 #ifdef _KERNEL
 209 extern struct anon *swap_anon(struct vnode *vp, uoff_t off);
 210 extern int swap_phys_alloc(struct vnode **vpp, uoff_t *offp, size_t *lenp,
 211     uint_t flags);
 212 extern void swap_phys_free(struct vnode *vp, uoff_t off, size_t len);
 213 extern int swap_getphysname(struct vnode *vp, uoff_t off,
 214     struct vnode **pvpp, uoff_t *poffp);
 215 extern int swap_newphysname(struct vnode *vp, uoff_t offset,
 216     uoff_t *offp, size_t *lenp, struct vnode **pvpp, uoff_t *poffp);
 217
 218 extern struct swapinfo *swapinfo;
 219 extern int swap_debug;
 220 #endif  /* _KERNEL */
 221
 222 #ifdef SWAP_DEBUG
 223 #define SW_RENAME       0x01
 224 #define SW_RESV         0x02
 225 #define SW_ALLOC        0x04
 226 #define SW_CTL          0x08
 227 #define SWAP_PRINT(f, s, x1, x2, x3, x4, x5) \
 228                 if (swap_debug & f) \
 229                         printf(s, x1, x2, x3, x4, x5);
 230 #else   /* SWAP_DEBUG */
 231 #define SWAP_PRINT(f, s, x1, x2, x3, x4, x5)
 232 #endif  /* SWAP_DEBUG */
 233
 234 #ifdef  __cplusplus
 235 }
 236 #endif
 237
 238 #endif  /* _SYS_SWAP_H */