include/vm/seg_map.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 2006 Sun Microsystems, Inc.  All rights reserved.
  23  * Use is subject to license terms.
  24  */
  25
  26 /*      Copyright (c) 1984, 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 _VM_SEG_MAP_H
  40 #define _VM_SEG_MAP_H
  41
  42 #ifdef  __cplusplus
  43 extern "C" {
  44 #endif
  45
  46 /*
  47  * When segmap is created it is possible to program its behavior,
  48  *      using the create args [needed for performance reasons].
  49  * Segmap creates n lists of pages.
  50  *      For VAC machines, there will be at least one free list
  51  *      per color. If more than one free list per color is needed,
  52  *      set nfreelist as needed.
  53  *
  54  *      For PAC machines, it will be treated as VAC with only one
  55  *      color- every page is of the same color. Again, set nfreelist
  56  *      to get more than one free list.
  57  */
  58 struct segmap_crargs {
  59         uint_t  prot;
  60         uint_t  shmsize;        /* shm_alignment for VAC, 0 for PAC. */
  61         uint_t  nfreelist;      /* number of freelist per color, >= 1 */
  62 };
  63
  64 #include <vm/kpm.h>
  65 #include <vm/vpm.h>
  66
  67 /*
  68  * Each smap struct represents a MAXBSIZE sized mapping to the
  69  * <sm_vp, sm_off> given in the structure.  The location of the
  70  * the structure in the array gives the virtual address of the
  71  * mapping. Structure rearranged for 64bit sm_off.
  72  */
  73 struct  smap {
  74         kmutex_t        sm_mtx;         /* protect non-list fields */
  75         struct  vnode   *sm_vp;         /* vnode pointer (if mapped) */
  76         struct  smap    *sm_hash;       /* hash pointer */
  77         struct  smap    *sm_next;       /* next pointer */
  78         struct  smap    *sm_prev;       /* previous pointer */
  79         uoff_t          sm_off;         /* file offset for mapping */
  80         ushort_t        sm_bitmap;      /* bit map for locked translations */
  81         ushort_t        sm_refcnt;      /* reference count for uses */
  82         ushort_t        sm_flags;       /* smap flags */
  83         ushort_t        sm_free_ndx;    /* freelist */
  84 #ifdef  SEGKPM_SUPPORT
  85         struct kpme     sm_kpme;        /* segkpm */
  86 #endif
  87 };
  88
  89 #ifdef  SEGKPM_SUPPORT
  90 #define GET_KPME(smp)   (&(smp)->sm_kpme)
  91 #define sm_kpme_next    sm_kpme.kpe_next
  92 #define sm_kpme_prev    sm_kpme.kpe_prev
  93 #define sm_kpme_page    sm_kpme.kpe_page
  94 #else
  95 #define GET_KPME(smp)   ((struct kpme *)NULL)
  96 #endif
  97
  98 /* sm_flags */
  99 #define SM_KPM_NEWPAGE     0x00000001   /* page created in segmap_getmapft */
 100 #define SM_NOTKPM_RELEASED 0x00000002   /* released smap not in segkpm mode */
 101 #define SM_QNDX_ZERO       0x00000004   /* on the index 0 freelist */
 102 #define SM_READ_DATA       0x00000010   /* page created for read */
 103 #define SM_WRITE_DATA      0x00000020   /* page created for write */
 104
 105 /*
 106  * Multiple smap free lists are maintained so that allocations
 107  * will scale with cpu count. Each free list is made up of 2 queues
 108  * so that allocations and deallocations can proceed concurrently.
 109  * Each queue structure is padded to 64 bytes to avoid false sharing.
 110  */
 111 #define SM_FREEQ_PAD (64 - sizeof (struct smap *) - sizeof (kmutex_t))
 112 struct  sm_freeq {
 113         struct smap     *smq_free;      /* points into freelist */
 114         kmutex_t        smq_mtx;        /* protects smq_free */
 115         char            smq_pad[SM_FREEQ_PAD];
 116 };
 117
 118 struct  smfree {
 119         struct sm_freeq sm_freeq[2];    /* alloc and release queues */
 120         struct sm_freeq *sm_allocq;     /* current allocq */
 121         struct sm_freeq *sm_releq;      /* current releq */
 122         kcondvar_t      sm_free_cv;
 123         ushort_t        sm_want;        /* someone wants a slot of this color */
 124 };
 125
 126 /*
 127  * Cached smaps are kept on hash chains to enable fast reclaim lookups.
 128  */
 129 struct  smaphash {
 130         kmutex_t        sh_mtx;         /* protects this hash chain */
 131         struct  smap    *sh_hash_list;  /* start of hash chain */
 132 };
 133
 134 /*
 135  * (Semi) private data maintained by the segmap driver per SEGMENT mapping
 136  * All fields in segmap_data are read-only after the segment is created.
 137  *
 138  */
 139
 140 struct  segmap_data {
 141         struct  smap    *smd_sm;        /* array of smap structures */
 142         long            smd_npages;     /* size of smap array */
 143         struct smfree   *smd_free;      /* ptr to freelist header array */
 144         struct smaphash *smd_hash;      /* ptr to hash header array */
 145         int             smd_nfree;      /* number of free lists */
 146         uchar_t         smd_prot;       /* protections for all smap's */
 147 };
 148
 149 /*
 150  * Statistics for segmap operations.
 151  *
 152  * No explicit locking to protect these stats.
 153  */
 154 struct segmapcnt {
 155         kstat_named_t   smp_fault;      /* number of segmap_faults */
 156         kstat_named_t   smp_faulta;     /* number of segmap_faultas */
 157         kstat_named_t   smp_getmap;     /* number of segmap_getmaps */
 158         kstat_named_t   smp_get_use;    /* getmaps that reuse existing map */
 159         kstat_named_t   smp_get_reclaim; /* getmaps that do a reclaim */
 160         kstat_named_t   smp_get_reuse;  /* getmaps that reuse a slot */
 161         kstat_named_t   smp_get_unused; /* getmaps that reuse existing map */
 162         kstat_named_t   smp_get_nofree; /* getmaps with no free slots */
 163         kstat_named_t   smp_rel_async;  /* releases that are async */
 164         kstat_named_t   smp_rel_write;  /* releases that write */
 165         kstat_named_t   smp_rel_free;   /* releases that free */
 166         kstat_named_t   smp_rel_abort;  /* releases that abort */
 167         kstat_named_t   smp_rel_dontneed; /* releases with dontneed set */
 168         kstat_named_t   smp_release;    /* releases with no other action */
 169         kstat_named_t   smp_pagecreate; /* pagecreates */
 170         kstat_named_t   smp_free_notfree; /* pages not freed in */
 171                                         /* segmap_pagefree */
 172         kstat_named_t   smp_free_dirty; /* dirty pages freeed */
 173                                         /* in segmap_pagefree */
 174         kstat_named_t   smp_free;       /* clean pages freeed in */
 175                                         /* segmap_pagefree */
 176         kstat_named_t   smp_stolen;     /* segmap_getmapflt() stole */
 177                                         /* from get_free_smp() */
 178         kstat_named_t   smp_get_nomtx;  /* free smaps but no mutex */
 179 };
 180
 181 /*
 182  * These are flags used on release.  Some of these might get handled
 183  * by segment operations needed for msync (when we figure them out).
 184  * SM_ASYNC modifies SM_WRITE.  SM_DONTNEED modifies SM_FREE.  SM_FREE
 185  * and SM_INVAL as well as SM_FREE and SM_DESTROY are mutually exclusive.
 186  * SM_DESTROY behaves like SM_INVAL but also forces the pages to be
 187  * destroyed -- this prevents them from being written to the backing
 188  * store.
 189  */
 190 #define SM_WRITE        0x01            /* write back the pages upon release */
 191 #define SM_ASYNC        0x02            /* do the write asynchronously */
 192 #define SM_FREE         0x04            /* put pages back on free list */
 193 #define SM_INVAL        0x08            /* invalidate page (no caching) */
 194 #define SM_DONTNEED     0x10            /* less likely to be needed soon */
 195 #define SM_DESTROY      0x20            /* invalidate page, don't write back */
 196
 197 /*
 198  * These are the forcefault flags used on getmapflt.
 199  *
 200  * The orginal semantic was extended to allow using the segkpm mapping
 201  * scheme w/o a major segmap interface change for MAXBSIZE == PAGESIZE
 202  * (which is required to enable segkpm for MAXBSIZE > PAGESIZE).
 203  * Most segmap consumers needn't to be changed at all or only need to
 204  * be changed slightly to take advantage of segkpm. Because the segkpm
 205  * virtual address is based on the physical address of a page, a page is
 206  * required to determine the virtual address (return value). Pages mapped
 207  * with segkpm are always at least read locked and are hence protected
 208  * from pageout or fsflush from segmap_getmap until segmap_release. This
 209  * implies, that the segkpm mappings are locked within this period too.
 210  * No trap driven segmap_fault's are possible in segkpm mode.
 211  *
 212  * The following combinations of "forcefault" and "rw" allow segkpm mode.
 213  * (1) SM_FAULT, S_READ
 214  * (2) SM_FAULT, S_WRITE
 215  * (3) SM_PAGECREATE, S_WRITE
 216  * (4) SM_LOCKPROTO, {S_READ, S_WRITE, S_OTHER}
 217  *
 218  * The regular additional operations (come in pairs in most of the cases):
 219  * . segmap_pagecreate/segmap_pageunlock
 220  * . segmap_fault(F_SOFTLOCK)/segmap_fault(F_SOFTUNLOCK)
 221  *
 222  * are mostly a no-op in segkpm mode with the following exceptions:
 223  * . The "newpage" return value of segmap_pagecreate is still supported
 224  *   for zeroout operations needed on newly created pages.
 225  *
 226  * . segmap_fault() must follow when a error could be expected in
 227  *   the fop_getpage. In segkpm mode this error is recognized in
 228  *   segmap_getmapflt and returned from the following segmap_fault()
 229  *   call. The "hole" optimization (read only after first fop_getpage
 230  *   mapping in segmap_getmapflt followed by a trap driven protection
 231  *   fault and a second fop_getpage via segmap_fault) cannot be used.
 232  *
 233  * . segmap_fault(F_SOFTUNLOCK) must follow when segmap_getmapflt was
 234  *   called w/ (SM_LOCKPROTO, S_OTHER). S_WRITE has to be applied, when
 235  *   the page should be marked "dirty". Otherwise the page is not
 236  *   written to the backing store later (as mentioned above, no page
 237  *   or protection faults are possible in segkpm mode). Caller cannot
 238  *   use only S_OTHER and rely on a protection fault to force the page
 239  *   to become dirty.
 240  *
 241  * . The segmap_pagecreate parameter softlock is ignored, pages and
 242  *   mappings are locked anyway.
 243  *
 244  * SM_LOCKPROTO is used in the fbio layer and some special segmap consumers.
 245  */
 246 #define SM_PAGECREATE   0x00            /* create page in segkpm mode, no I/O */
 247 #define SM_FAULT        0x01            /* fault in page if necessary */
 248 #define SM_LOCKPROTO    0x02            /* lock/unlock protocol used */
 249
 250 #define MAXBSHIFT       13              /* log2(MAXBSIZE) */
 251
 252 #define MAXBOFFSET      (MAXBSIZE - 1)
 253 #define MAXBMASK        (~MAXBOFFSET)
 254
 255 /*
 256  * SMAP_HASHAVELEN is the average length desired for this chain, from
 257  * which the size of the smd_hash table is derived at segment create time.
 258  * SMAP_HASHVPSHIFT is defined so that 1 << SMAP_HASHVPSHIFT is the
 259  * approximate size of a vnode struct.
 260  */
 261 #define SMAP_HASHAVELEN         4
 262 #define SMAP_HASHVPSHIFT        6
 263
 264
 265 #ifdef _KERNEL
 266 /*
 267  * The kernel generic mapping segment.
 268  */
 269 extern struct seg *segkmap;
 270
 271 /*
 272  * Public seg_map segment operations.
 273  */
 274 extern int      segmap_create(struct seg *, void *);
 275 extern int      segmap_pagecreate(struct seg *, caddr_t, size_t, int);
 276 extern void     segmap_pageunlock(struct seg *, caddr_t, size_t, enum seg_rw);
 277 extern faultcode_t segmap_fault(struct hat *, struct seg *, caddr_t, size_t,
 278                 enum fault_type, enum seg_rw);
 279 extern caddr_t  segmap_getmap(struct seg *, struct vnode *, uoff_t);
 280 extern caddr_t  segmap_getmapflt(struct seg *, struct vnode *, uoff_t,
 281                 size_t, int, enum seg_rw);
 282 extern int      segmap_release(struct seg *, caddr_t, uint_t);
 283 extern void     segmap_flush(struct seg *, struct vnode *);
 284 extern void     segmap_inval(struct seg *, struct vnode *, uoff_t);
 285
 286 #endif  /* _KERNEL */
 287
 288 #ifdef  __cplusplus
 289 }
 290 #endif
 291
 292 #endif  /* _VM_SEG_MAP_H */