freebsd-dev/sys/fs/procfs/procfs_map.c
John Dyson 95e5e988e0 Make our v_usecount vnode reference count work identically to the
original BSD code.  The association between the vnode and the vm_object
no longer includes reference counts.  The major difference is that
vm_object's are no longer freed gratuitiously from the vnode, and so
once an object is created for the vnode, it will last as long as the
vnode does.

When a vnode object reference count is incremented, then the underlying
vnode reference count is incremented also.  The two "objects" are now
more intimately related, and so the interactions are now much less
complex.

When vnodes are now normally placed onto the free queue with an object still
attached.  The rundown of the object happens at vnode rundown time, and
happens with exactly the same filesystem semantics of the original VFS
code.  There is absolutely no need for vnode_pager_uncache and other
travesties like that anymore.

A side-effect of these changes is that SMP locking should be much simpler,
the I/O copyin/copyout optimizations work, NFS should be more ponderable,
and further work on layered filesystems should be less frustrating, because
of the totally coherent management of the vnode objects and vnodes.

Please be careful with your system while running this code, but I would
greatly appreciate feedback as soon a reasonably possible.
1998-01-06 05:26:17 +00:00

173 lines
4.9 KiB
C

/*
* Copyright (c) 1993 Jan-Simon Pendry
* Copyright (c) 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Jan-Simon Pendry.
*
* 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.
*
* @(#)procfs_status.c 8.3 (Berkeley) 2/17/94
*
* $Id: procfs_map.c,v 1.13 1997/11/14 22:57:46 tegge Exp $
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/vnode.h>
#include <miscfs/procfs/procfs.h>
#include <vm/vm.h>
#include <vm/vm_prot.h>
#include <sys/lock.h>
#include <vm/pmap.h>
#include <vm/vm_map.h>
#include <vm/vm_page.h>
#include <vm/vm_object.h>
#define MEBUFFERSIZE 256
/*
* The map entries can *almost* be read with programs like cat. However,
* large maps need special programs to read. It is not easy to implement
* a program that can sense the required size of the buffer, and then
* subsequently do a read with the appropriate size. This operation cannot
* be atomic. The best that we can do is to allow the program to do a read
* with an arbitrarily large buffer, and return as much as we can. We can
* return an error code if the buffer is too small (EFBIG), then the program
* can try a bigger buffer.
*/
int
procfs_domap(curp, p, pfs, uio)
struct proc *curp;
struct proc *p;
struct pfsnode *pfs;
struct uio *uio;
{
int len;
int error;
vm_map_t map = &p->p_vmspace->vm_map;
pmap_t pmap = &p->p_vmspace->vm_pmap;
vm_map_entry_t entry;
char mebuffer[MEBUFFERSIZE];
if (uio->uio_rw != UIO_READ)
return (EOPNOTSUPP);
if (uio->uio_offset != 0)
return (0);
error = 0;
if (map != &curproc->p_vmspace->vm_map)
vm_map_lock_read(map);
for (entry = map->header.next;
((uio->uio_resid > 0) && (entry != &map->header));
entry = entry->next) {
vm_object_t obj, tobj, lobj;
vm_offset_t addr;
int resident, privateresident;
char *type;
if (entry->eflags & (MAP_ENTRY_IS_A_MAP|MAP_ENTRY_IS_SUB_MAP))
continue;
obj = entry->object.vm_object;
if (obj && (obj->shadow_count == 1))
privateresident = obj->resident_page_count;
else
privateresident = 0;
resident = 0;
addr = entry->start;
while (addr < entry->end) {
if (pmap_extract( pmap, addr))
resident++;
addr += PAGE_SIZE;
}
for( lobj = tobj = obj; tobj; tobj = tobj->backing_object)
lobj = tobj;
if (lobj) switch(lobj->type) {
default:
case OBJT_DEFAULT:
type = "default";
break;
case OBJT_VNODE:
type = "vnode";
break;
case OBJT_SWAP:
type = "swap";
break;
case OBJT_DEVICE:
type = "device";
break;
} else {
type = "none";
}
/*
* format:
* start, end, resident, private resident, cow, access, type.
*/
sprintf(mebuffer, "0x%-8.8x 0x%-8.8x %9d %9d %s%s%s %s %s\n",
entry->start, entry->end,
resident, privateresident,
(entry->protection & VM_PROT_READ)?"r":"-",
(entry->protection & VM_PROT_WRITE)?"w":"-",
(entry->protection & VM_PROT_EXECUTE)?"x":"-",
(entry->eflags & MAP_ENTRY_COW)?"COW":" ",
type);
len = strlen(mebuffer);
if (len > uio->uio_resid) {
error = EFBIG;
break;
}
error = uiomove(mebuffer, len, uio);
if (error)
break;
}
if (map != &curproc->p_vmspace->vm_map)
vm_map_unlock_read(map);
return error;
}
int
procfs_validmap(p)
struct proc *p;
{
return ((p->p_flag & P_SYSTEM) == 0);
}