uvm_vnode.c

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    1 /*      $NetBSD: uvm_vnode.c,v 1.90 2008/01/02 11:49:21 ad Exp $        */
    2 
    3 /*
    4  * Copyright (c) 1997 Charles D. Cranor and Washington University.
    5  * Copyright (c) 1991, 1993
    6  *      The Regents of the University of California.
    7  * Copyright (c) 1990 University of Utah.
    8  *
    9  * All rights reserved.
   10  *
   11  * This code is derived from software contributed to Berkeley by
   12  * the Systems Programming Group of the University of Utah Computer
   13  * Science Department.
   14  *
   15  * Redistribution and use in source and binary forms, with or without
   16  * modification, are permitted provided that the following conditions
   17  * are met:
   18  * 1. Redistributions of source code must retain the above copyright
   19  *    notice, this list of conditions and the following disclaimer.
   20  * 2. Redistributions in binary form must reproduce the above copyright
   21  *    notice, this list of conditions and the following disclaimer in the
   22  *    documentation and/or other materials provided with the distribution.
   23  * 3. All advertising materials mentioning features or use of this software
   24  *    must display the following acknowledgement:
   25  *      This product includes software developed by Charles D. Cranor,
   26  *      Washington University, the University of California, Berkeley and
   27  *      its contributors.
   28  * 4. Neither the name of the University nor the names of its contributors
   29  *    may be used to endorse or promote products derived from this software
   30  *    without specific prior written permission.
   31  *
   32  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   33  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   34  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   35  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   36  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   37  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   38  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   39  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   40  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   41  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   42  * SUCH DAMAGE.
   43  *
   44  *      @(#)vnode_pager.c       8.8 (Berkeley) 2/13/94
   45  * from: Id: uvm_vnode.c,v 1.1.2.26 1998/02/02 20:38:07 chuck Exp
   46  */
   47 
   48 /*
   49  * uvm_vnode.c: the vnode pager.
   50  */
   51 
   52 #include <sys/cdefs.h>
   53 __KERNEL_RCSID(0, "$NetBSD: uvm_vnode.c,v 1.90 2008/01/02 11:49:21 ad Exp $");
   54 
   55 #include "fs_nfs.h"
   56 #include "opt_uvmhist.h"
   57 #include "opt_ddb.h"
   58 
   59 #include <sys/param.h>
   60 #include <sys/systm.h>
   61 #include <sys/kernel.h>
   62 #include <sys/proc.h>
   63 #include <sys/malloc.h>
   64 #include <sys/vnode.h>
   65 #include <sys/disklabel.h>
   66 #include <sys/ioctl.h>
   67 #include <sys/fcntl.h>
   68 #include <sys/conf.h>
   69 #include <sys/pool.h>
   70 #include <sys/mount.h>
   71 
   72 #include <miscfs/specfs/specdev.h>
   73 
   74 #include <uvm/uvm.h>
   75 #include <uvm/uvm_readahead.h>
   76 
   77 /*
   78  * functions
   79  */
   80 
   81 static void     uvn_detach(struct uvm_object *);
   82 static int      uvn_get(struct uvm_object *, voff_t, struct vm_page **, int *,
   83                         int, vm_prot_t, int, int);
   84 static int      uvn_put(struct uvm_object *, voff_t, voff_t, int);
   85 static void     uvn_reference(struct uvm_object *);
   86 
   87 static int      uvn_findpage(struct uvm_object *, voff_t, struct vm_page **,
   88                              int);
   89 
   90 /*
   91  * master pager structure
   92  */
   93 
   94 const struct uvm_pagerops uvm_vnodeops = {
   95         .pgo_reference = uvn_reference,
   96         .pgo_detach = uvn_detach,
   97         .pgo_get = uvn_get,
   98         .pgo_put = uvn_put,
   99 };
  100 
  101 /*
  102  * the ops!
  103  */
  104 
  105 /*
  106  * uvn_reference
  107  *
  108  * duplicate a reference to a VM object.  Note that the reference
  109  * count must already be at least one (the passed in reference) so
  110  * there is no chance of the uvn being killed or locked out here.
  111  *
  112  * => caller must call with object unlocked.
  113  * => caller must be using the same accessprot as was used at attach time
  114  */
  115 
  116 static void
  117 uvn_reference(struct uvm_object *uobj)
  118 {
  119         VREF((struct vnode *)uobj);
  120 }
  121 
  122 
  123 /*
  124  * uvn_detach
  125  *
  126  * remove a reference to a VM object.
  127  *
  128  * => caller must call with object unlocked and map locked.
  129  */
  130 
  131 static void
  132 uvn_detach(struct uvm_object *uobj)
  133 {
  134         vrele((struct vnode *)uobj);
  135 }
  136 
  137 /*
  138  * uvn_put: flush page data to backing store.
  139  *
  140  * => object must be locked on entry!   VOP_PUTPAGES must unlock it.
  141  * => flags: PGO_SYNCIO -- use sync. I/O
  142  * => note: caller must set PG_CLEAN and pmap_clear_modify (if needed)
  143  */
  144 
  145 static int
  146 uvn_put(struct uvm_object *uobj, voff_t offlo, voff_t offhi, int flags)
  147 {
  148         struct vnode *vp = (struct vnode *)uobj;
  149         int error;
  150 
  151         KASSERT(mutex_owned(&vp->v_interlock));
  152         error = VOP_PUTPAGES(vp, offlo, offhi, flags);
  153 
  154         return error;
  155 }
  156 
  157 
  158 /*
  159  * uvn_get: get pages (synchronously) from backing store
  160  *
  161  * => prefer map unlocked (not required)
  162  * => object must be locked!  we will _unlock_ it before starting any I/O.
  163  * => flags: PGO_ALLPAGES: get all of the pages
  164  *           PGO_LOCKED: fault data structures are locked
  165  * => NOTE: offset is the offset of pps[0], _NOT_ pps[centeridx]
  166  * => NOTE: caller must check for released pages!!
  167  */
  168 
  169 static int
  170 uvn_get(struct uvm_object *uobj, voff_t offset,
  171     struct vm_page **pps /* IN/OUT */,
  172     int *npagesp /* IN (OUT if PGO_LOCKED)*/,
  173     int centeridx, vm_prot_t access_type, int advice, int flags)
  174 {
  175         struct vnode *vp = (struct vnode *)uobj;
  176         int error;
  177 
  178         UVMHIST_FUNC("uvn_get"); UVMHIST_CALLED(ubchist);
  179 
  180         UVMHIST_LOG(ubchist, "vp %p off 0x%x", vp, (int)offset, 0,0);
  181 
  182         if ((access_type & VM_PROT_WRITE) == 0 && (flags & PGO_LOCKED) == 0) {
  183                 vn_ra_allocctx(vp);
  184                 uvm_ra_request(vp->v_ractx, advice, uobj, offset,
  185                     *npagesp << PAGE_SHIFT);
  186         }
  187 
  188         error = VOP_GETPAGES(vp, offset, pps, npagesp, centeridx,
  189                              access_type, advice, flags);
  190 
  191         KASSERT(((flags & PGO_LOCKED) != 0 && mutex_owned(&vp->v_interlock)) ||
  192             (flags & PGO_LOCKED) == 0);
  193         return error;
  194 }
  195 
  196 
  197 /*
  198  * uvn_findpages:
  199  * return the page for the uobj and offset requested, allocating if needed.
  200  * => uobj must be locked.
  201  * => returned pages will be BUSY.
  202  */
  203 
  204 int
  205 uvn_findpages(struct uvm_object *uobj, voff_t offset, int *npagesp,
  206     struct vm_page **pgs, int flags)
  207 {
  208         int i, count, found, npages, rv;
  209 
  210         count = found = 0;
  211         npages = *npagesp;
  212         if (flags & UFP_BACKWARD) {
  213                 for (i = npages - 1; i >= 0; i--, offset -= PAGE_SIZE) {
  214                         rv = uvn_findpage(uobj, offset, &pgs[i], flags);
  215                         if (rv == 0) {
  216                                 if (flags & UFP_DIRTYONLY)
  217                                         break;
  218                         } else
  219                                 found++;
  220                         count++;
  221                 }
  222         } else {
  223                 for (i = 0; i < npages; i++, offset += PAGE_SIZE) {
  224                         rv = uvn_findpage(uobj, offset, &pgs[i], flags);
  225                         if (rv == 0) {
  226                                 if (flags & UFP_DIRTYONLY)
  227                                         break;
  228                         } else
  229                                 found++;
  230                         count++;
  231                 }
  232         }
  233         *npagesp = count;
  234         return (found);
  235 }
  236 
  237 static int
  238 uvn_findpage(struct uvm_object *uobj, voff_t offset, struct vm_page **pgp,
  239     int flags)
  240 {
  241         struct vm_page *pg;
  242         bool dirty;
  243         UVMHIST_FUNC("uvn_findpage"); UVMHIST_CALLED(ubchist);
  244         UVMHIST_LOG(ubchist, "vp %p off 0x%lx", uobj, offset,0,0);
  245 
  246         if (*pgp != NULL) {
  247                 UVMHIST_LOG(ubchist, "dontcare", 0,0,0,0);
  248                 return 0;
  249         }
  250         for (;;) {
  251                 /* look for an existing page */
  252                 pg = uvm_pagelookup(uobj, offset);
  253 
  254                 /* nope?  allocate one now */
  255                 if (pg == NULL) {
  256                         if (flags & UFP_NOALLOC) {
  257                                 UVMHIST_LOG(ubchist, "noalloc", 0,0,0,0);
  258                                 return 0;
  259                         }
  260                         pg = uvm_pagealloc(uobj, offset, NULL, 0);
  261                         if (pg == NULL) {
  262                                 if (flags & UFP_NOWAIT) {
  263                                         UVMHIST_LOG(ubchist, "nowait",0,0,0,0);
  264                                         return 0;
  265                                 }
  266                                 mutex_exit(&uobj->vmobjlock);
  267                                 uvm_wait("uvn_fp1");
  268                                 mutex_enter(&uobj->vmobjlock);
  269                                 continue;
  270                         }
  271                         UVMHIST_LOG(ubchist, "alloced %p", pg,0,0,0);
  272                         break;
  273                 } else if (flags & UFP_NOCACHE) {
  274                         UVMHIST_LOG(ubchist, "nocache",0,0,0,0);
  275                         return 0;
  276                 }
  277 
  278                 /* page is there, see if we need to wait on it */
  279                 if ((pg->flags & PG_BUSY) != 0) {
  280                         if (flags & UFP_NOWAIT) {
  281                                 UVMHIST_LOG(ubchist, "nowait",0,0,0,0);
  282                                 return 0;
  283                         }
  284                         pg->flags |= PG_WANTED;
  285                         UVMHIST_LOG(ubchist, "wait %p", pg,0,0,0);
  286                         UVM_UNLOCK_AND_WAIT(pg, &uobj->vmobjlock, 0,
  287                                             "uvn_fp2", 0);
  288                         mutex_enter(&uobj->vmobjlock);
  289                         continue;
  290                 }
  291 
  292                 /* skip PG_RDONLY pages if requested */
  293                 if ((flags & UFP_NORDONLY) && (pg->flags & PG_RDONLY)) {
  294                         UVMHIST_LOG(ubchist, "nordonly",0,0,0,0);
  295                         return 0;
  296                 }
  297 
  298                 /* stop on clean pages if requested */
  299                 if (flags & UFP_DIRTYONLY) {
  300                         dirty = pmap_clear_modify(pg) ||
  301                                 (pg->flags & PG_CLEAN) == 0;
  302                         pg->flags |= PG_CLEAN;
  303                         if (!dirty) {
  304                                 UVMHIST_LOG(ubchist, "dirtonly", 0,0,0,0);
  305                                 return 0;
  306                         }
  307                 }
  308 
  309                 /* mark the page BUSY and we're done. */
  310                 pg->flags |= PG_BUSY;
  311                 UVM_PAGE_OWN(pg, "uvn_findpage");
  312                 UVMHIST_LOG(ubchist, "found %p", pg,0,0,0);
  313                 break;
  314         }
  315         *pgp = pg;
  316         return 1;
  317 }
  318 
  319 /*
  320  * uvm_vnp_setsize: grow or shrink a vnode uobj
  321  *
  322  * grow   => just update size value
  323  * shrink => toss un-needed pages
  324  *
  325  * => we assume that the caller has a reference of some sort to the
  326  *      vnode in question so that it will not be yanked out from under
  327  *      us.
  328  */
  329 
  330 void
  331 uvm_vnp_setsize(struct vnode *vp, voff_t newsize)
  332 {
  333         struct uvm_object *uobj = &vp->v_uobj;
  334         voff_t pgend = round_page(newsize);
  335         voff_t oldsize;
  336         UVMHIST_FUNC("uvm_vnp_setsize"); UVMHIST_CALLED(ubchist);
  337 
  338         mutex_enter(&uobj->vmobjlock);
  339         UVMHIST_LOG(ubchist, "vp %p old 0x%x new 0x%x",
  340             vp, vp->v_size, newsize, 0);
  341 
  342         /*
  343          * now check if the size has changed: if we shrink we had better
  344          * toss some pages...
  345          */
  346 
  347         KASSERT(newsize != VSIZENOTSET);
  348         KASSERT(vp->v_size <= vp->v_writesize);
  349         KASSERT(vp->v_size == vp->v_writesize ||
  350             newsize == vp->v_writesize || newsize <= vp->v_size);
  351 
  352         oldsize = vp->v_writesize;
  353         KASSERT(oldsize != VSIZENOTSET || pgend > oldsize);
  354 
  355         if (oldsize > pgend) {
  356                 (void) uvn_put(uobj, pgend, 0, PGO_FREE | PGO_SYNCIO);
  357                 mutex_enter(&uobj->vmobjlock);
  358         }
  359         vp->v_size = vp->v_writesize = newsize;
  360         mutex_exit(&uobj->vmobjlock);
  361 }
  362 
  363 void
  364 uvm_vnp_setwritesize(struct vnode *vp, voff_t newsize)
  365 {
  366 
  367         mutex_enter(&vp->v_interlock);
  368         KASSERT(newsize != VSIZENOTSET);
  369         KASSERT(vp->v_size != VSIZENOTSET);
  370         KASSERT(vp->v_writesize != VSIZENOTSET);
  371         KASSERT(vp->v_size <= vp->v_writesize);
  372         KASSERT(vp->v_size <= newsize);
  373         vp->v_writesize = newsize;
  374         mutex_exit(&vp->v_interlock);
  375 }
  376 
  377 /*
  378  * uvm_vnp_zerorange:  set a range of bytes in a file to zero.
  379  */
  380 
  381 void
  382 uvm_vnp_zerorange(struct vnode *vp, off_t off, size_t len)
  383 {
  384         void *win;
  385         int flags;
  386 
  387         /*
  388          * XXXUBC invent kzero() and use it
  389          */
  390 
  391         while (len) {
  392                 vsize_t bytelen = len;
  393 
  394                 win = ubc_alloc(&vp->v_uobj, off, &bytelen, UVM_ADV_NORMAL,
  395                     UBC_WRITE);
  396                 memset(win, 0, bytelen);
  397                 flags = UBC_WANT_UNMAP(vp) ? UBC_UNMAP : 0;
  398                 ubc_release(win, flags);
  399 
  400                 off += bytelen;
  401                 len -= bytelen;
  402         }
  403 }
  404 
  405 bool
  406 uvn_text_p(struct uvm_object *uobj)
  407 {
  408         struct vnode *vp = (struct vnode *)uobj;
  409 
  410         return (vp->v_iflag & VI_EXECMAP) != 0;
  411 }
  412 
  413 bool
  414 uvn_clean_p(struct uvm_object *uobj)
  415 {
  416         struct vnode *vp = (struct vnode *)uobj;
  417 
  418         return (vp->v_iflag & VI_ONWORKLST) == 0;
  419 }
  420 
  421 bool
  422 uvn_needs_writefault_p(struct uvm_object *uobj)
  423 {
  424         struct vnode *vp = (struct vnode *)uobj;
  425 
  426         return uvn_clean_p(uobj) ||
  427             (vp->v_iflag & (VI_WRMAP|VI_WRMAPDIRTY)) == VI_WRMAP;
  428 }
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FreeBSD/Linux Kernel Cross Reference sys/uvm/uvm_vnode.c

FreeBSD/Linux Kernel Cross Reference
sys/uvm/uvm_vnode.c
