uvm_page.c

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/*	$NetBSD: uvm_page.c,v 1.46 2000/12/01 09:54:42 chs Exp $	*/

/* 
 * 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  [e-mail]
 *  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_uvmhist.h"

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/malloc.h>
#include <sys/sched.h>
#include <sys/kernel.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 */

/*
 * Some supported CPUs in a given architecture don't support all
 * of the things necessary to do idle page zero'ing efficiently.
 * We therefore provide a way to disable it from machdep code here.
 */
/*
 * XXX disabled until we can find a way to do this without causing
 * problems for either cpu caches or DMA latency.
 */
boolean_t vm_page_zero_enable = FALSE;

extern struct uvm_pagerops uvm_vnodeops;

/*
 * 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 the allocator is ready.
 * we static allocate the one bootstrap bucket below...
 */

static struct pglist uvm_bootbucket;

/*
 * local prototypes
 */

static void uvm_pageinsert __P((struct vm_page *));
static void uvm_pageremove __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
 */

#ifndef OSKIT
static __inline void
#else
static void
#endif
uvm_pageremove(pg)
	struct vm_page *pg;
{
	struct pglist *buck;
	int s;

	KASSERT(pg->flags & PG_TABLED);
	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);

	if (pg->uobject->pgops == &uvm_vnodeops) {
		uvmexp.vnodepages--;
	}

	/* 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;
{
	vsize_t freepages, pagecount, n;
	vm_page_t pagearray;
	int lcv, i;  
	paddr_t paddr;

	/*
	 * step 1: init the page queues and page queue locks
	 */
	for (lcv = 0; lcv < VM_NFREELIST; lcv++) {
		for (i = 0; i < PGFL_NQUEUES; i++)
			TAILQ_INIT(&uvm.page_free[lcv].pgfl_queues[i]);
	}
	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 allocate 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("uvm_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 %ld page(s) in init\n",
			    (long)(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 locks for kernel threads
	 */

	simple_lock_init(&uvm.pagedaemon_lock);
	simple_lock_init(&uvm.aiodoned_lock);

	/*
	 * step 7: init reserve thresholds
	 * XXXCDC - values may need adjusting
	 */
	uvmexp.reserve_pagedaemon = 1;
	uvmexp.reserve_kernel = 5;

	/*
	 * step 8: determine if we should zero pages in the idle
	 * loop.
	 */
	uvm.page_idle_zero = vm_page_zero_enable;

	/*
	 * done!
	 */

	uvm.page_init_done = TRUE;
}

/*
 * uvm_setpagesize: set the page size
 * 
 * => sets page_shift and page_mask from uvmexp.pagesize.
 */   

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 */

	static boolean_t initialized = FALSE;
	vaddr_t addr, vaddr;
	paddr_t paddr;

	/* round to page size */
	size = round_page(size);

	/*
	 * on first call to this function, initialize ourselves.
	 */
	if (initialized == FALSE) {
		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);

		initialized = TRUE;
	}

	/*
	 * allocate virtual memory for this request
	 */
	if (virtual_space_start == virtual_space_end ||
	    (virtual_space_end - virtual_space_start) < size)
		panic("uvm_pageboot_alloc: out of virtual space");

	addr = virtual_space_start;

#ifdef PMAP_GROWKERNEL
	/*
	 * If the kernel pmap can't map the requested space,
	 * then allocate more resources for it.
	 */
	if (uvm_maxkaddr < (addr + size)) {
		uvm_maxkaddr = pmap_growkernel(addr + size);
		if (uvm_maxkaddr < (addr + size))
			panic("uvm_pageboot_alloc: pmap_growkernel() failed");
	}
#endif

	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");