freebsd-dev/sys/vm/vm_pager.c
Poul-Henning Kamp 923502ff91 useracc() the prequel:
Merge the contents (less some trivial bordering the silly comments)
of <vm/vm_prot.h> and <vm/vm_inherit.h> into <vm/vm.h>.  This puts
the #defines for the vm_inherit_t and vm_prot_t types next to their
typedefs.

This paves the road for the commit to follow shortly: change
useracc() to use VM_PROT_{READ|WRITE} rather than B_{READ|WRITE}
as argument.
1999-10-29 18:09:36 +00:00

608 lines
14 KiB
C

/*
* Copyright (c) 1991, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* The Mach Operating System project at Carnegie-Mellon University.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* from: @(#)vm_pager.c 8.6 (Berkeley) 1/12/94
*
*
* Copyright (c) 1987, 1990 Carnegie-Mellon University.
* All rights reserved.
*
* Authors: Avadis Tevanian, Jr., Michael Wayne Young
*
* Permission to use, copy, modify and distribute this software and
* its documentation is hereby granted, provided that both the copyright
* notice and this permission notice appear in all copies of the
* software, derivative works or modified versions, and any portions
* thereof, and that both notices appear in supporting documentation.
*
* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
* FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
*
* Carnegie Mellon requests users of this software to return to
*
* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
* School of Computer Science
* Carnegie Mellon University
* Pittsburgh PA 15213-3890
*
* any improvements or extensions that they make and grant Carnegie the
* rights to redistribute these changes.
*
* $FreeBSD$
*/
/*
* Paging space routine stubs. Emulates a matchmaker-like interface
* for builtin pagers.
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/vnode.h>
#include <sys/buf.h>
#include <sys/ucred.h>
#include <sys/malloc.h>
#include <sys/proc.h>
#include <vm/vm.h>
#include <vm/vm_param.h>
#include <vm/vm_object.h>
#include <vm/vm_page.h>
#include <vm/vm_pager.h>
#include <vm/vm_extern.h>
MALLOC_DEFINE(M_VMPGDATA, "VM pgdata", "XXX: VM pager private data");
extern struct pagerops defaultpagerops;
extern struct pagerops swappagerops;
extern struct pagerops vnodepagerops;
extern struct pagerops devicepagerops;
int cluster_pbuf_freecnt = -1; /* unlimited to begin with */
static int dead_pager_getpages __P((vm_object_t, vm_page_t *, int, int));
static vm_object_t dead_pager_alloc __P((void *, vm_ooffset_t, vm_prot_t,
vm_ooffset_t));
static void dead_pager_putpages __P((vm_object_t, vm_page_t *, int, int, int *));
static boolean_t dead_pager_haspage __P((vm_object_t, vm_pindex_t, int *, int *));
static void dead_pager_dealloc __P((vm_object_t));
static int
dead_pager_getpages(obj, ma, count, req)
vm_object_t obj;
vm_page_t *ma;
int count;
int req;
{
return VM_PAGER_FAIL;
}
static vm_object_t
dead_pager_alloc(handle, size, prot, off)
void *handle;
vm_ooffset_t size;
vm_prot_t prot;
vm_ooffset_t off;
{
return NULL;
}
static void
dead_pager_putpages(object, m, count, flags, rtvals)
vm_object_t object;
vm_page_t *m;
int count;
int flags;
int *rtvals;
{
int i;
for (i = 0; i < count; i++) {
rtvals[i] = VM_PAGER_AGAIN;
}
}
static int
dead_pager_haspage(object, pindex, prev, next)
vm_object_t object;
vm_pindex_t pindex;
int *prev;
int *next;
{
if (prev)
*prev = 0;
if (next)
*next = 0;
return FALSE;
}
static void
dead_pager_dealloc(object)
vm_object_t object;
{
return;
}
static struct pagerops deadpagerops = {
NULL,
dead_pager_alloc,
dead_pager_dealloc,
dead_pager_getpages,
dead_pager_putpages,
dead_pager_haspage,
NULL
};
struct pagerops *pagertab[] = {
&defaultpagerops, /* OBJT_DEFAULT */
&swappagerops, /* OBJT_SWAP */
&vnodepagerops, /* OBJT_VNODE */
&devicepagerops, /* OBJT_DEVICE */
&deadpagerops /* OBJT_DEAD */
};
int npagers = sizeof(pagertab) / sizeof(pagertab[0]);
/*
* Kernel address space for mapping pages.
* Used by pagers where KVAs are needed for IO.
*
* XXX needs to be large enough to support the number of pending async
* cleaning requests (NPENDINGIO == 64) * the maximum swap cluster size
* (MAXPHYS == 64k) if you want to get the most efficiency.
*/
#define PAGER_MAP_SIZE (8 * 1024 * 1024)
int pager_map_size = PAGER_MAP_SIZE;
vm_map_t pager_map;
static int bswneeded;
static vm_offset_t swapbkva; /* swap buffers kva */
void
vm_pager_init()
{
struct pagerops **pgops;
/*
* Initialize known pagers
*/
for (pgops = pagertab; pgops < &pagertab[npagers]; pgops++)
if (pgops && ((*pgops)->pgo_init != NULL))
(*(*pgops)->pgo_init) ();
}
void
vm_pager_bufferinit()
{
struct buf *bp;
int i;
bp = swbuf;
/*
* Now set up swap and physical I/O buffer headers.
*/
for (i = 0; i < nswbuf; i++, bp++) {
TAILQ_INSERT_HEAD(&bswlist, bp, b_freelist);
BUF_LOCKINIT(bp);
LIST_INIT(&bp->b_dep);
bp->b_rcred = bp->b_wcred = NOCRED;
bp->b_xflags = 0;
}
cluster_pbuf_freecnt = nswbuf / 2;
swapbkva = kmem_alloc_pageable(pager_map, nswbuf * MAXPHYS);
if (!swapbkva)
panic("Not enough pager_map VM space for physical buffers");
}
/*
* Allocate an instance of a pager of the given type.
* Size, protection and offset parameters are passed in for pagers that
* need to perform page-level validation (e.g. the device pager).
*/
vm_object_t
vm_pager_allocate(objtype_t type, void *handle, vm_ooffset_t size, vm_prot_t prot,
vm_ooffset_t off)
{
struct pagerops *ops;
ops = pagertab[type];
if (ops)
return ((*ops->pgo_alloc) (handle, size, prot, off));
return (NULL);
}
void
vm_pager_deallocate(object)
vm_object_t object;
{
(*pagertab[object->type]->pgo_dealloc) (object);
}
/*
* vm_pager_strategy:
*
* called with no specific spl
* Execute strategy routine directly to pager.
*/
void
vm_pager_strategy(vm_object_t object, struct buf *bp)
{
if (pagertab[object->type]->pgo_strategy) {
(*pagertab[object->type]->pgo_strategy)(object, bp);
} else {
bp->b_flags |= B_ERROR;
bp->b_error = ENXIO;
biodone(bp);
}
}
/*
* vm_pager_get_pages() - inline, see vm/vm_pager.h
* vm_pager_put_pages() - inline, see vm/vm_pager.h
* vm_pager_has_page() - inline, see vm/vm_pager.h
* vm_pager_page_inserted() - inline, see vm/vm_pager.h
* vm_pager_page_removed() - inline, see vm/vm_pager.h
*/
#if 0
/*
* vm_pager_sync:
*
* Called by pageout daemon before going back to sleep.
* Gives pagers a chance to clean up any completed async pageing
* operations.
*/
void
vm_pager_sync()
{
struct pagerops **pgops;
for (pgops = pagertab; pgops < &pagertab[npagers]; pgops++)
if (pgops && ((*pgops)->pgo_sync != NULL))
(*(*pgops)->pgo_sync) ();
}
#endif
vm_offset_t
vm_pager_map_page(m)
vm_page_t m;
{
vm_offset_t kva;
kva = kmem_alloc_wait(pager_map, PAGE_SIZE);
pmap_kenter(kva, VM_PAGE_TO_PHYS(m));
return (kva);
}
void
vm_pager_unmap_page(kva)
vm_offset_t kva;
{
pmap_kremove(kva);
kmem_free_wakeup(pager_map, kva, PAGE_SIZE);
}
vm_object_t
vm_pager_object_lookup(pg_list, handle)
register struct pagerlst *pg_list;
void *handle;
{
register vm_object_t object;
for (object = TAILQ_FIRST(pg_list); object != NULL; object = TAILQ_NEXT(object,pager_object_list))
if (object->handle == handle)
return (object);
return (NULL);
}
/*
* initialize a physical buffer
*/
static void
initpbuf(struct buf *bp)
{
bp->b_rcred = NOCRED;
bp->b_wcred = NOCRED;
bp->b_qindex = QUEUE_NONE;
bp->b_data = (caddr_t) (MAXPHYS * (bp - swbuf)) + swapbkva;
bp->b_kvabase = bp->b_data;
bp->b_kvasize = MAXPHYS;
bp->b_xflags = 0;
bp->b_flags = 0;
bp->b_error = 0;
BUF_LOCK(bp, LK_EXCLUSIVE);
}
/*
* allocate a physical buffer
*
* There are a limited number (nswbuf) of physical buffers. We need
* to make sure that no single subsystem is able to hog all of them,
* so each subsystem implements a counter which is typically initialized
* to 1/2 nswbuf. getpbuf() decrements this counter in allocation and
* increments it on release, and blocks if the counter hits zero. A
* subsystem may initialize the counter to -1 to disable the feature,
* but it must still be sure to match up all uses of getpbuf() with
* relpbuf() using the same variable.
*
* NOTE: pfreecnt can be NULL, but this 'feature' will be removed
* relatively soon when the rest of the subsystems get smart about it. XXX
*/
struct buf *
getpbuf(pfreecnt)
int *pfreecnt;
{
int s;
struct buf *bp;
s = splvm();
for (;;) {
if (pfreecnt) {
while (*pfreecnt == 0) {
tsleep(pfreecnt, PVM, "wswbuf0", 0);
}
}
/* get a bp from the swap buffer header pool */
if ((bp = TAILQ_FIRST(&bswlist)) != NULL)
break;
bswneeded = 1;
tsleep(&bswneeded, PVM, "wswbuf1", 0);
/* loop in case someone else grabbed one */
}
TAILQ_REMOVE(&bswlist, bp, b_freelist);
if (pfreecnt)
--*pfreecnt;
splx(s);
initpbuf(bp);
return bp;
}
/*
* allocate a physical buffer, if one is available.
*
* Note that there is no NULL hack here - all subsystems using this
* call understand how to use pfreecnt.
*/
struct buf *
trypbuf(pfreecnt)
int *pfreecnt;
{
int s;
struct buf *bp;
s = splvm();
if (*pfreecnt == 0 || (bp = TAILQ_FIRST(&bswlist)) == NULL) {
splx(s);
return NULL;
}
TAILQ_REMOVE(&bswlist, bp, b_freelist);
--*pfreecnt;
splx(s);
initpbuf(bp);
return bp;
}
/*
* release a physical buffer
*
* NOTE: pfreecnt can be NULL, but this 'feature' will be removed
* relatively soon when the rest of the subsystems get smart about it. XXX
*/
void
relpbuf(bp, pfreecnt)
struct buf *bp;
int *pfreecnt;
{
int s;
s = splvm();
if (bp->b_rcred != NOCRED) {
crfree(bp->b_rcred);
bp->b_rcred = NOCRED;
}
if (bp->b_wcred != NOCRED) {
crfree(bp->b_wcred);
bp->b_wcred = NOCRED;
}
if (bp->b_vp)
pbrelvp(bp);
BUF_UNLOCK(bp);
TAILQ_INSERT_HEAD(&bswlist, bp, b_freelist);
if (bswneeded) {
bswneeded = 0;
wakeup(&bswneeded);
}
if (pfreecnt) {
if (++*pfreecnt == 1)
wakeup(pfreecnt);
}
splx(s);
}
/********************************************************
* CHAINING FUNCTIONS *
********************************************************
*
* These functions support recursion of I/O operations
* on bp's, typically by chaining one or more 'child' bp's
* to the parent. Synchronous, asynchronous, and semi-synchronous
* chaining is possible.
*/
/*
* vm_pager_chain_iodone:
*
* io completion routine for child bp. Currently we fudge a bit
* on dealing with b_resid. Since users of these routines may issue
* multiple children simultaniously, sequencing of the error can be lost.
*/
static void
vm_pager_chain_iodone(struct buf *nbp)
{
struct buf *bp;
if ((bp = nbp->b_chain.parent) != NULL) {
if (nbp->b_flags & B_ERROR) {
bp->b_flags |= B_ERROR;
bp->b_error = nbp->b_error;
} else if (nbp->b_resid != 0) {
bp->b_flags |= B_ERROR;
bp->b_error = EINVAL;
} else {
bp->b_resid -= nbp->b_bcount;
}
nbp->b_chain.parent = NULL;
--bp->b_chain.count;
if (bp->b_flags & B_WANT) {
bp->b_flags &= ~B_WANT;
wakeup(bp);
}
if (!bp->b_chain.count && (bp->b_flags & B_AUTOCHAINDONE)) {
bp->b_flags &= ~B_AUTOCHAINDONE;
if (bp->b_resid != 0 && !(bp->b_flags & B_ERROR)) {
bp->b_flags |= B_ERROR;
bp->b_error = EINVAL;
}
biodone(bp);
}
}
nbp->b_flags |= B_DONE;
nbp->b_flags &= ~B_ASYNC;
relpbuf(nbp, NULL);
}
/*
* getchainbuf:
*
* Obtain a physical buffer and chain it to its parent buffer. When
* I/O completes, the parent buffer will be B_SIGNAL'd. Errors are
* automatically propogated to the parent
*
* Since these are brand new buffers, we do not have to clear B_INVAL
* and B_ERROR because they are already clear.
*/
struct buf *
getchainbuf(struct buf *bp, struct vnode *vp, int flags)
{
struct buf *nbp = getpbuf(NULL);
nbp->b_chain.parent = bp;
++bp->b_chain.count;
if (bp->b_chain.count > 4)
waitchainbuf(bp, 4, 0);
nbp->b_flags = B_CALL | (bp->b_flags & B_ORDERED) | flags;
nbp->b_rcred = nbp->b_wcred = proc0.p_ucred;
nbp->b_iodone = vm_pager_chain_iodone;
crhold(nbp->b_rcred);
crhold(nbp->b_wcred);
if (vp)
pbgetvp(vp, nbp);
return(nbp);
}
void
flushchainbuf(struct buf *nbp)
{
if (nbp->b_bcount) {
nbp->b_bufsize = nbp->b_bcount;
if ((nbp->b_flags & B_READ) == 0)
nbp->b_dirtyend = nbp->b_bcount;
BUF_KERNPROC(nbp);
VOP_STRATEGY(nbp->b_vp, nbp);
} else {
biodone(nbp);
}
}
void
waitchainbuf(struct buf *bp, int count, int done)
{
int s;
s = splbio();
while (bp->b_chain.count > count) {
bp->b_flags |= B_WANT;
tsleep(bp, PRIBIO + 4, "bpchain", 0);
}
if (done) {
if (bp->b_resid != 0 && !(bp->b_flags & B_ERROR)) {
bp->b_flags |= B_ERROR;
bp->b_error = EINVAL;
}
biodone(bp);
}
splx(s);
}
void
autochaindone(struct buf *bp)
{
int s;
s = splbio();
if (bp->b_chain.count == 0)
biodone(bp);
else
bp->b_flags |= B_AUTOCHAINDONE;
splx(s);
}