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NetBSD/sys/uvm/uvm_page.c

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/* $NetBSD: uvm_page.c,v 1.15 1998/10/18 23:50:00 chs Exp $ */
/*
* XXXCDC: "ROUGH DRAFT" QUALITY UVM PRE-RELEASE FILE!
* >>>USE AT YOUR OWN RISK, WORK IS NOT FINISHED<<<
*/
/*
* Copyright (c) 1997 Charles D. Cranor and Washington University.
* 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 Charles D. Cranor,
* Washington University, 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.
*
* @(#)vm_page.c 8.3 (Berkeley) 3/21/94
* from: Id: uvm_page.c,v 1.1.2.18 1998/02/06 05:24:42 chs Exp
*
*
* Copyright (c) 1987, 1990 Carnegie-Mellon University.
* All rights reserved.
*
* 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.
*/
/*
* uvm_page.c: page ops.
*/
#include "opt_pmap_new.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/malloc.h>
#include <sys/proc.h>
#include <vm/vm.h>
#include <vm/vm_page.h>
#include <vm/vm_kern.h>
#define UVM_PAGE /* pull in uvm_page.h functions */
#include <uvm/uvm.h>
/*
* global vars... XXXCDC: move to uvm. structure.
*/
/*
* physical memory config is stored in vm_physmem.
*/
struct vm_physseg vm_physmem[VM_PHYSSEG_MAX]; /* XXXCDC: uvm.physmem */
int vm_nphysseg = 0; /* XXXCDC: uvm.nphysseg */
/*
* local variables
*/
/*
* these variables record the values returned by vm_page_bootstrap,
* for debugging purposes. The implementation of uvm_pageboot_alloc
* and pmap_startup here also uses them internally.
*/
static vaddr_t virtual_space_start;
static vaddr_t virtual_space_end;
/*
* we use a hash table with only one bucket during bootup. we will
* later rehash (resize) the hash table once malloc() is ready.
* we static allocate the bootstrap bucket below...
*/
static struct pglist uvm_bootbucket;
/*
* local prototypes
*/
static void uvm_pageinsert __P((struct vm_page *));
/*
* inline functions
*/
/*
* uvm_pageinsert: insert a page in the object and the hash table
*
* => caller must lock object
* => caller must lock page queues
* => call should have already set pg's object and offset pointers
* and bumped the version counter
*/
__inline static void
uvm_pageinsert(pg)
struct vm_page *pg;
{
struct pglist *buck;
int s;
#ifdef DIAGNOSTIC
if (pg->flags & PG_TABLED)
panic("uvm_pageinsert: already inserted");
#endif
buck = &uvm.page_hash[uvm_pagehash(pg->uobject,pg->offset)];
s = splimp();
simple_lock(&uvm.hashlock);
TAILQ_INSERT_TAIL(buck, pg, hashq); /* put in hash */
simple_unlock(&uvm.hashlock);
splx(s);
TAILQ_INSERT_TAIL(&pg->uobject->memq, pg, listq); /* put in object */
pg->flags |= PG_TABLED;
pg->uobject->uo_npages++;
}
/*
* uvm_page_remove: remove page from object and hash
*
* => caller must lock object
* => caller must lock page queues
*/
void __inline
uvm_pageremove(pg)
struct vm_page *pg;
{
struct pglist *buck;
int s;
#ifdef DIAGNOSTIC
if ((pg->flags & (PG_FAULTING)) != 0)
panic("uvm_pageremove: page is faulting");
#endif
if ((pg->flags & PG_TABLED) == 0)
return; /* XXX: log */
buck = &uvm.page_hash[uvm_pagehash(pg->uobject,pg->offset)];
s = splimp();
simple_lock(&uvm.hashlock);
TAILQ_REMOVE(buck, pg, hashq);
simple_unlock(&uvm.hashlock);
splx(s);
/* object should be locked */
TAILQ_REMOVE(&pg->uobject->memq, pg, listq);
pg->flags &= ~PG_TABLED;
pg->uobject->uo_npages--;
pg->uobject = NULL;
pg->version++;
}
/*
* uvm_page_init: init the page system. called from uvm_init().
*
* => we return the range of kernel virtual memory in kvm_startp/kvm_endp
*/
void
uvm_page_init(kvm_startp, kvm_endp)
vaddr_t *kvm_startp, *kvm_endp;
{
int freepages, pagecount;
vm_page_t pagearray;
int lcv, n, i;
paddr_t paddr;
/*
* step 1: init the page queues and page queue locks
*/
for (lcv = 0; lcv < VM_NFREELIST; lcv++)
TAILQ_INIT(&uvm.page_free[lcv]);
TAILQ_INIT(&uvm.page_active);
TAILQ_INIT(&uvm.page_inactive_swp);
TAILQ_INIT(&uvm.page_inactive_obj);
simple_lock_init(&uvm.pageqlock);
simple_lock_init(&uvm.fpageqlock);
/*
* step 2: init the <obj,offset> => <page> hash table. for now
* we just have one bucket (the bootstrap bucket). later on we
* will malloc() new buckets as we dynamically resize the hash table.
*/
uvm.page_nhash = 1; /* 1 bucket */
uvm.page_hashmask = 0; /* mask for hash function */
uvm.page_hash = &uvm_bootbucket; /* install bootstrap bucket */
TAILQ_INIT(uvm.page_hash); /* init hash table */
simple_lock_init(&uvm.hashlock); /* init hash table lock */
/*
* step 3: allocate vm_page structures.
*/
/*
* sanity check:
* before calling this function the MD code is expected to register
* some free RAM with the uvm_page_physload() function. our job
* now is to allocate vm_page structures for this memory.
*/
if (vm_nphysseg == 0)
panic("vm_page_bootstrap: no memory pre-allocated");
/*
* first calculate the number of free pages...
*
* note that we use start/end rather than avail_start/avail_end.
* this allows us to allocate extra vm_page structures in case we
* want to return some memory to the pool after booting.
*/
freepages = 0;
for (lcv = 0 ; lcv < vm_nphysseg ; lcv++)
freepages += (vm_physmem[lcv].end - vm_physmem[lcv].start);
/*
* we now know we have (PAGE_SIZE * freepages) bytes of memory we can
* use. for each page of memory we use we need a vm_page structure.
* thus, the total number of pages we can use is the total size of
* the memory divided by the PAGE_SIZE plus the size of the vm_page
* structure. we add one to freepages as a fudge factor to avoid
* truncation errors (since we can only allocate in terms of whole
* pages).
*/
pagecount = ((freepages + 1) << PAGE_SHIFT) /
(PAGE_SIZE + sizeof(struct vm_page));
pagearray = (vm_page_t)uvm_pageboot_alloc(pagecount *
sizeof(struct vm_page));
memset(pagearray, 0, pagecount * sizeof(struct vm_page));
/*
* step 4: init the vm_page structures and put them in the correct
* place...
*/
for (lcv = 0 ; lcv < vm_nphysseg ; lcv++) {
n = vm_physmem[lcv].end - vm_physmem[lcv].start;
if (n > pagecount) {
printf("uvm_page_init: lost %d page(s) in init\n",
n - pagecount);
panic("uvm_page_init"); /* XXXCDC: shouldn't happen? */
/* n = pagecount; */
}
/* set up page array pointers */
vm_physmem[lcv].pgs = pagearray;
pagearray += n;
pagecount -= n;
vm_physmem[lcv].lastpg = vm_physmem[lcv].pgs + (n - 1);
/* init and free vm_pages (we've already zeroed them) */
paddr = ptoa(vm_physmem[lcv].start);
for (i = 0 ; i < n ; i++, paddr += PAGE_SIZE) {
vm_physmem[lcv].pgs[i].phys_addr = paddr;
if (atop(paddr) >= vm_physmem[lcv].avail_start &&
atop(paddr) <= vm_physmem[lcv].avail_end) {
uvmexp.npages++;
/* add page to free pool */
uvm_pagefree(&vm_physmem[lcv].pgs[i]);
}
}
}
/*
* step 5: pass up the values of virtual_space_start and
* virtual_space_end (obtained by uvm_pageboot_alloc) to the upper
* layers of the VM.
*/
*kvm_startp = round_page(virtual_space_start);
*kvm_endp = trunc_page(virtual_space_end);
/*
* step 6: init pagedaemon lock
*/
simple_lock_init(&uvm.pagedaemon_lock);
/*
* step 7: init reserve thresholds
* XXXCDC - values may need adjusting
*/
uvmexp.reserve_pagedaemon = 1;
uvmexp.reserve_kernel = 5;
/*
* done!
*/
}
/*
* uvm_setpagesize: set the page size
*
* => sets page_shift and page_mask from uvmexp.pagesize.
* => XXXCDC: move global vars.
*/
void
uvm_setpagesize()
{
if (uvmexp.pagesize == 0)
uvmexp.pagesize = DEFAULT_PAGE_SIZE;
uvmexp.pagemask = uvmexp.pagesize - 1;
if ((uvmexp.pagemask & uvmexp.pagesize) != 0)
panic("uvm_setpagesize: page size not a power of two");
for (uvmexp.pageshift = 0; ; uvmexp.pageshift++)
if ((1 << uvmexp.pageshift) == uvmexp.pagesize)
break;
}
/*
* uvm_pageboot_alloc: steal memory from physmem for bootstrapping
*/
vaddr_t
uvm_pageboot_alloc(size)
vsize_t size;
{
#if defined(PMAP_STEAL_MEMORY)
vaddr_t addr;
/*
* defer bootstrap allocation to MD code (it may want to allocate
* from a direct-mapped segment). pmap_steal_memory should round
* off virtual_space_start/virtual_space_end.
*/
addr = pmap_steal_memory(size, &virtual_space_start,
&virtual_space_end);
return(addr);
#else /* !PMAP_STEAL_MEMORY */
vaddr_t addr, vaddr;
paddr_t paddr;
/* round to page size */
size = round_page(size);
/*
* on first call to this function init ourselves. we detect this
* by checking virtual_space_start/end which are in the zero'd BSS area.
*/
if (virtual_space_start == virtual_space_end) {
pmap_virtual_space(&virtual_space_start, &virtual_space_end);
/* round it the way we like it */
virtual_space_start = round_page(virtual_space_start);
virtual_space_end = trunc_page(virtual_space_end);
}
/*
* allocate virtual memory for this request
*/
addr = virtual_space_start;
virtual_space_start += size;
/*
* allocate and mapin physical pages to back new virtual pages
*/
for (vaddr = round_page(addr) ; vaddr < addr + size ;
vaddr += PAGE_SIZE) {
if (!uvm_page_physget(&paddr))
panic("uvm_pageboot_alloc: out of memory");
/* XXX: should be wired, but some pmaps don't like that ... */
#if defined(PMAP_NEW)
pmap_kenter_pa(vaddr, paddr, VM_PROT_READ|VM_PROT_WRITE);
#else
pmap_enter(pmap_kernel(), vaddr, paddr,
VM_PROT_READ|VM_PROT_WRITE, FALSE);
#endif
}
return(addr);
#endif /* PMAP_STEAL_MEMORY */
}
#if !defined(PMAP_STEAL_MEMORY)
/*
* uvm_page_physget: "steal" one page from the vm_physmem structure.
*
* => attempt to allocate it off the end of a segment in which the "avail"
* values match the start/end values. if we can't do that, then we
* will advance both values (making them equal, and removing some
* vm_page structures from the non-avail area).
* => return false if out of memory.
*/
boolean_t
uvm_page_physget(paddrp)
paddr_t *paddrp;
{
int lcv, x;
/* pass 1: try allocating from a matching end */
#if (VM_PHYSSEG_STRAT == VM_PSTRAT_BIGFIRST)
for (lcv = vm_nphysseg - 1 ; lcv >= 0 ; lcv--)
#else
for (lcv = 0 ; lcv < vm_nphysseg ; lcv++)
#endif
{
if (vm_physmem[lcv].pgs)
panic("vm_page_physget: called _after_ bootstrap");
/* try from front */
if (vm_physmem[lcv].avail_start == vm_physmem[lcv].start &&
vm_physmem[lcv].avail_start < vm_physmem[lcv].avail_end) {
*paddrp = ptoa(vm_physmem[lcv].avail_start);
vm_physmem[lcv].avail_start++;
vm_physmem[lcv].start++;
/* nothing left? nuke it */
if (vm_physmem[lcv].avail_start ==
vm_physmem[lcv].end) {
if (vm_nphysseg == 1)
panic("vm_page_physget: out of memory!");
vm_nphysseg--;
for (x = lcv ; x < vm_nphysseg ; x++)
/* structure copy */
vm_physmem[x] = vm_physmem[x+1];
}
return (TRUE);
}
/* try from rear */
if (vm_physmem[lcv].avail_end == vm_physmem[lcv].end &&
vm_physmem[lcv].avail_start < vm_physmem[lcv].avail_end) {
*paddrp = ptoa(vm_physmem[lcv].avail_end - 1);
vm_physmem[lcv].avail_end--;
vm_physmem[lcv].end--;
/* nothing left? nuke it */
if (vm_physmem[lcv].avail_end ==
vm_physmem[lcv].start) {
if (vm_nphysseg == 1)
panic("vm_page_physget: out of memory!");
vm_nphysseg--;
for (x = lcv ; x < vm_nphysseg ; x++)
/* structure copy */
vm_physmem[x] = vm_physmem[x+1];
}
return (TRUE);
}
}
/* pass2: forget about matching ends, just allocate something */
#if (VM_PHYSSEG_STRAT == VM_PSTRAT_BIGFIRST)
for (lcv = vm_nphysseg - 1 ; lcv >= 0 ; lcv--)
#else
for (lcv = 0 ; lcv < vm_nphysseg ; lcv++)
#endif
{
/* any room in this bank? */
if (vm_physmem[lcv].avail_start >= vm_physmem[lcv].avail_end)
continue; /* nope */
*paddrp = ptoa(vm_physmem[lcv].avail_start);
vm_physmem[lcv].avail_start++;
/* truncate! */
vm_physmem[lcv].start = vm_physmem[lcv].avail_start;
/* nothing left? nuke it */
if (vm_physmem[lcv].avail_start == vm_physmem[lcv].end) {
if (vm_nphysseg == 1)
panic("vm_page_physget: out of memory!");
vm_nphysseg--;
for (x = lcv ; x < vm_nphysseg ; x++)
/* structure copy */
vm_physmem[x] = vm_physmem[x+1];
}
return (TRUE);
}
return (FALSE); /* whoops! */
}
#endif /* PMAP_STEAL_MEMORY */
/*
* uvm_page_physload: load physical memory into VM system
*
* => all args are PFs
* => all pages in start/end get vm_page structures
* => areas marked by avail_start/avail_end get added to the free page pool
* => we are limited to VM_PHYSSEG_MAX physical memory segments
*/
void
uvm_page_physload(start, end, avail_start, avail_end, free_list)
vaddr_t start, end, avail_start, avail_end;
int free_list;
{
int preload, lcv;
psize_t npages;
struct vm_page *pgs;
struct vm_physseg *ps;
if (uvmexp.pagesize == 0)
panic("vm_page_physload: page size not set!");
if (free_list >= VM_NFREELIST || free_list < VM_FREELIST_DEFAULT)
panic("uvm_page_physload: bad free list %d\n", free_list);
/*
* do we have room?
*/
if (vm_nphysseg == VM_PHYSSEG_MAX) {
printf("vm_page_physload: unable to load physical memory "
"segment\n");
printf("\t%d segments allocated, ignoring 0x%lx -> 0x%lx\n",
VM_PHYSSEG_MAX, start, end);
return;
}
/*
* check to see if this is a "preload" (i.e. uvm_mem_init hasn't been
* called yet, so malloc is not available).
*/
for (lcv = 0 ; lcv < vm_nphysseg ; lcv++) {
if (vm_physmem[lcv].pgs)
break;
}
preload = (lcv == vm_nphysseg);
/*
* if VM is already running, attempt to malloc() vm_page structures
*/
if (!preload) {
#if defined(VM_PHYSSEG_NOADD)
panic("vm_page_physload: tried to add RAM after vm_mem_init");
#else
/* XXXCDC: need some sort of lockout for this case */
paddr_t paddr;
npages = end - start; /* # of pages */
MALLOC(pgs, struct vm_page *, sizeof(struct vm_page) * npages,
M_VMPAGE, M_NOWAIT);
if (pgs == NULL) {
printf("vm_page_physload: can not malloc vm_page "
"structs for segment\n");
printf("\tignoring 0x%lx -> 0x%lx\n", start, end);
return;
}
/* zero data, init phys_addr and free_list, and free pages */
memset(pgs, 0, sizeof(struct vm_page) * npages);
for (lcv = 0, paddr = ptoa(start) ;
lcv < npages ; lcv++, paddr += PAGE_SIZE) {
pgs[lcv].phys_addr = paddr;
pgs[lcv].free_list = free_list;
if (atop(paddr) >= avail_start &&
atop(paddr) <= avail_end)
uvm_pagefree(&pgs[lcv]);
}
/* XXXCDC: incomplete: need to update uvmexp.free, what else? */
/* XXXCDC: need hook to tell pmap to rebuild pv_list, etc... */
#endif
} else {
/* gcc complains if these don't get init'd */
pgs = NULL;
npages = 0;
}
/*
* now insert us in the proper place in vm_physmem[]
*/
#if (VM_PHYSSEG_STRAT == VM_PSTRAT_RANDOM)
/* random: put it at the end (easy!) */
ps = &vm_physmem[vm_nphysseg];
#elif (VM_PHYSSEG_STRAT == VM_PSTRAT_BSEARCH)
{
int x;
/* sort by address for binary search */
for (lcv = 0 ; lcv < vm_nphysseg ; lcv++)
if (start < vm_physmem[lcv].start)
break;
ps = &vm_physmem[lcv];
/* move back other entries, if necessary ... */
for (x = vm_nphysseg ; x > lcv ; x--)
/* structure copy */
vm_physmem[x] = vm_physmem[x - 1];
}
#elif (VM_PHYSSEG_STRAT == VM_PSTRAT_BIGFIRST)
{
int x;
/* sort by largest segment first */
for (lcv = 0 ; lcv < vm_nphysseg ; lcv++)
if ((end - start) >
(vm_physmem[lcv].end - vm_physmem[lcv].start))
break;
ps = &vm_physmem[lcv];
/* move back other entries, if necessary ... */
for (x = vm_nphysseg ; x > lcv ; x--)
/* structure copy */
vm_physmem[x] = vm_physmem[x - 1];
}
#else
panic("vm_page_physload: unknown physseg strategy selected!");
#endif
ps->start = start;
ps->end = end;
ps->avail_start = avail_start;
ps->avail_end = avail_end;
if (preload) {
ps->pgs = NULL;
} else {
ps->pgs = pgs;
ps->lastpg = pgs + npages - 1;
}
ps->free_list = free_list;
vm_nphysseg++;
/*
* done!
*/
if (!preload)
uvm_page_rehash();
return;
}
/*
* uvm_page_rehash: reallocate hash table based on number of free pages.
*/
void
uvm_page_rehash()
{
int freepages, lcv, bucketcount, s, oldcount;
struct pglist *newbuckets, *oldbuckets;
struct vm_page *pg;
/*
* compute number of pages that can go in the free pool
*/
freepages = 0;
for (lcv = 0 ; lcv < vm_nphysseg ; lcv++)
freepages +=
(vm_physmem[lcv].avail_end - vm_physmem[lcv].avail_start);
/*
* compute number of buckets needed for this number of pages
*/
bucketcount = 1;
while (bucketcount < freepages)
bucketcount = bucketcount * 2;
/*
* malloc new buckets
*/
MALLOC(newbuckets, struct pglist *, sizeof(struct pglist) * bucketcount,
M_VMPBUCKET, M_NOWAIT);
if (newbuckets == NULL) {
printf("vm_page_physrehash: WARNING: could not grow page "
"hash table\n");
return;
}
for (lcv = 0 ; lcv < bucketcount ; lcv++)
TAILQ_INIT(&newbuckets[lcv]);
/*
* now replace the old buckets with the new ones and rehash everything
*/
s = splimp();
simple_lock(&uvm.hashlock);
/* swap old for new ... */
oldbuckets = uvm.page_hash;
oldcount = uvm.page_nhash;
uvm.page_hash = newbuckets;
uvm.page_nhash = bucketcount;
uvm.page_hashmask = bucketcount - 1; /* power of 2 */
/* ... and rehash */
for (lcv = 0 ; lcv < oldcount ; lcv++) {
while ((pg = oldbuckets[lcv].tqh_first) != NULL) {
TAILQ_REMOVE(&oldbuckets[lcv], pg, hashq);
TAILQ_INSERT_TAIL(
&uvm.page_hash[uvm_pagehash(pg->uobject, pg->offset)],
pg, hashq);
}
}
simple_unlock(&uvm.hashlock);
splx(s);
/*
* free old bucket array if we malloc'd it previously
*/
if (oldbuckets != &uvm_bootbucket)
FREE(oldbuckets, M_VMPBUCKET);
/*
* done
*/
return;
}
#if 1 /* XXXCDC: TMP TMP TMP DEBUG DEBUG DEBUG */
void uvm_page_physdump __P((void)); /* SHUT UP GCC */
/* call from DDB */
void
uvm_page_physdump()
{
int lcv;
printf("rehash: physical memory config [segs=%d of %d]:\n",
vm_nphysseg, VM_PHYSSEG_MAX);
for (lcv = 0 ; lcv < vm_nphysseg ; lcv++)
printf("0x%lx->0x%lx [0x%lx->0x%lx]\n", vm_physmem[lcv].start,
vm_physmem[lcv].end, vm_physmem[lcv].avail_start,
vm_physmem[lcv].avail_end);
printf("STRATEGY = ");
switch (VM_PHYSSEG_STRAT) {
case VM_PSTRAT_RANDOM: printf("RANDOM\n"); break;
case VM_PSTRAT_BSEARCH: printf("BSEARCH\n"); break;
case VM_PSTRAT_BIGFIRST: printf("BIGFIRST\n"); break;
default: printf("<<UNKNOWN>>!!!!\n");
}
printf("number of buckets = %d\n", uvm.page_nhash);
}
#endif
/*
* uvm_pagealloc_strat: allocate vm_page from a particular free list.
*
* => return null if no pages free
* => wake up pagedaemon if number of free pages drops below low water mark
* => if obj != NULL, obj must be locked (to put in hash)
* => if anon != NULL, anon must be locked (to put in anon)
* => only one of obj or anon can be non-null
* => caller must activate/deactivate page if it is not wired.
* => free_list is ignored if strat == UVM_PGA_STRAT_NORMAL.
*/
struct vm_page *
uvm_pagealloc_strat(obj, off, anon, strat, free_list)
struct uvm_object *obj;
vaddr_t off;
struct vm_anon *anon;
int strat, free_list;
{
int lcv, s;
struct vm_page *pg;
struct pglist *freeq;
#ifdef DIAGNOSTIC
/* sanity check */
if (obj && anon)
panic("uvm_pagealloc: obj and anon != NULL");
#endif
s = splimp();
uvm_lock_fpageq(); /* lock free page queue */
/*
* check to see if we need to generate some free pages waking
* the pagedaemon.
*/
if (uvmexp.free < uvmexp.freemin || (uvmexp.free < uvmexp.freetarg &&
uvmexp.inactive < uvmexp.inactarg))
thread_wakeup(&uvm.pagedaemon);
/*
* fail if any of these conditions is true:
* [1] there really are no free pages, or
* [2] only kernel "reserved" pages remain and
* the page isn't being allocated to a kernel object.
* [3] only pagedaemon "reserved" pages remain and
* the requestor isn't the pagedaemon.
*/
if ((uvmexp.free <= uvmexp.reserve_kernel &&
!(obj && obj->uo_refs == UVM_OBJ_KERN)) ||
(uvmexp.free <= uvmexp.reserve_pagedaemon &&
!(obj == uvmexp.kmem_object && curproc == uvm.pagedaemon_proc)))
goto fail;
again:
switch (strat) {
case UVM_PGA_STRAT_NORMAL:
/* Check all freelists in descending priority order. */
for (lcv = 0; lcv < VM_NFREELIST; lcv++) {
freeq = &uvm.page_free[lcv];
if ((pg = freeq->tqh_first) != NULL)
goto gotit;
}
/* No pages free! */
goto fail;
case UVM_PGA_STRAT_ONLY:
case UVM_PGA_STRAT_FALLBACK:
/* Attempt to allocate from the specified free list. */
#ifdef DIAGNOSTIC
if (free_list >= VM_NFREELIST || free_list < 0)
panic("uvm_pagealloc_strat: bad free list %d",
free_list);
#endif
freeq = &uvm.page_free[free_list];
if ((pg = freeq->tqh_first) != NULL)
goto gotit;
/* Fall back, if possible. */
if (strat == UVM_PGA_STRAT_FALLBACK) {
strat = UVM_PGA_STRAT_NORMAL;
goto again;
}
/* No pages free! */
goto fail;
default:
panic("uvm_pagealloc_strat: bad strat %d", strat);
/* NOTREACHED */
}
gotit:
TAILQ_REMOVE(freeq, pg, pageq);
uvmexp.free--;
uvm_unlock_fpageq(); /* unlock free page queue */
splx(s);
pg->offset = off;
pg->uobject = obj;
pg->uanon = anon;
pg->flags = PG_BUSY|PG_CLEAN|PG_FAKE;
pg->version++;
pg->wire_count = 0;
pg->loan_count = 0;
if (anon) {
anon->u.an_page = pg;
pg->pqflags = PQ_ANON;
} else {
if (obj)
uvm_pageinsert(pg);
pg->pqflags = 0;
}
#if defined(UVM_PAGE_TRKOWN)
pg->owner_tag = NULL;
#endif
UVM_PAGE_OWN(pg, "new alloc");
return(pg);
fail:
uvm_unlock_fpageq();
splx(s);
return (NULL);
}
/*
* uvm_pagerealloc: reallocate a page from one object to another
*
* => both objects must be locked
*/
void
uvm_pagerealloc(pg, newobj, newoff)
struct vm_page *pg;
struct uvm_object *newobj;
vaddr_t newoff;
{
/*
* remove it from the old object
*/
if (pg->uobject) {
uvm_pageremove(pg);
}
/*
* put it in the new object
*/
if (newobj) {
pg->uobject = newobj;
pg->offset = newoff;
pg->version++;
uvm_pageinsert(pg);
}
return;
}
/*
* uvm_pagefree: free page
*
* => erase page's identity (i.e. remove from hash/object)
* => put page on free list
* => caller must lock owning object (either anon or uvm_object)
* => caller must lock page queues
* => assumes all valid mappings of pg are gone
*/
void uvm_pagefree(pg)
struct vm_page *pg;
{
int s;
int saved_loan_count = pg->loan_count;
/*
* if the page was an object page (and thus "TABLED"), remove it
* from the object.
*/
if (pg->flags & PG_TABLED) {
/*
* if the object page is on loan we are going to drop ownership.
* it is possible that an anon will take over as owner for this
* page later on. the anon will want a !PG_CLEAN page so that
* it knows it needs to allocate swap if it wants to page the
* page out.
*/
if (saved_loan_count)
pg->flags &= ~PG_CLEAN; /* in case an anon takes over */
uvm_pageremove(pg);
/*
* if our page was on loan, then we just lost control over it
* (in fact, if it was loaned to an anon, the anon may have
* already taken over ownership of the page by now and thus
* changed the loan_count [e.g. in uvmfault_anonget()]) we just
* return (when the last loan is dropped, then the page can be
* freed by whatever was holding the last loan).
*/
if (saved_loan_count)
return;
} else if (saved_loan_count && (pg->pqflags & PQ_ANON)) {
/*
* if our page is owned by an anon and is loaned out to the
* kernel then we just want to drop ownership and return.
* the kernel must free the page when all its loans clear ...
* note that the kernel can't change the loan status of our
* page as long as we are holding PQ lock.
*/
pg->pqflags &= ~PQ_ANON;
pg->uanon = NULL;
return;
}
#ifdef DIAGNOSTIC
if (saved_loan_count) {
printf("uvm_pagefree: warning: freeing page with a loan "
"count of %d\n", saved_loan_count);
panic("uvm_pagefree: loan count");
}
#endif
/*
* now remove the page from the queues
*/
if (pg->pqflags & PQ_ACTIVE) {
TAILQ_REMOVE(&uvm.page_active, pg, pageq);
pg->pqflags &= ~PQ_ACTIVE;
uvmexp.active--;
}
if (pg->pqflags & PQ_INACTIVE) {
if (pg->pqflags & PQ_SWAPBACKED)
TAILQ_REMOVE(&uvm.page_inactive_swp, pg, pageq);
else
TAILQ_REMOVE(&uvm.page_inactive_obj, pg, pageq);
pg->pqflags &= ~PQ_INACTIVE;
uvmexp.inactive--;
}
/*
* if the page was wired, unwire it now.
*/
if (pg->wire_count)
{
pg->wire_count = 0;
uvmexp.wired--;
}
/*
* and put on free queue
*/
s = splimp();
uvm_lock_fpageq();
TAILQ_INSERT_TAIL(&uvm.page_free[uvm_page_lookup_freelist(pg)],
pg, pageq);
pg->pqflags = PQ_FREE;
#ifdef DEBUG
pg->uobject = (void *)0xdeadbeef;
pg->offset = 0xdeadbeef;
pg->uanon = (void *)0xdeadbeef;
#endif
uvmexp.free++;
uvm_unlock_fpageq();
splx(s);
}
#if defined(UVM_PAGE_TRKOWN)
/*
* uvm_page_own: set or release page ownership
*
* => this is a debugging function that keeps track of who sets PG_BUSY
* and where they do it. it can be used to track down problems
* such a process setting "PG_BUSY" and never releasing it.
* => page's object [if any] must be locked
* => if "tag" is NULL then we are releasing page ownership
*/
void
uvm_page_own(pg, tag)
struct vm_page *pg;
char *tag;
{
/* gain ownership? */
if (tag) {
if (pg->owner_tag) {
printf("uvm_page_own: page %p already owned "
"by proc %d [%s]\n", pg,
pg->owner, pg->owner_tag);
panic("uvm_page_own");
}
pg->owner = (curproc) ? curproc->p_pid : (pid_t) -1;
pg->owner_tag = tag;
return;
}
/* drop ownership */
if (pg->owner_tag == NULL) {
printf("uvm_page_own: dropping ownership of an non-owned "
"page (%p)\n", pg);
panic("uvm_page_own");
}
pg->owner_tag = NULL;
return;
}
#endif
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