HAMMER 60I/Many: Mirroring

[dragonfly.git] / sys / vm / vm_kern.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_kern.c     8.3 (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: src/sys/vm/vm_kern.c,v 1.61.2.2 2002/03/12 18:25:26 tegge Exp $
 * $DragonFly: src/sys/vm/vm_kern.c,v 1.29 2007/06/07 23:14:29 dillon Exp $
 */

/*
 *      Kernel memory management.
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/malloc.h>
#include <sys/kernel.h>
#include <sys/sysctl.h>

#include <vm/vm.h>
#include <vm/vm_param.h>
#include <sys/lock.h>
#include <vm/pmap.h>
#include <vm/vm_map.h>
#include <vm/vm_object.h>
#include <vm/vm_page.h>
#include <vm/vm_pageout.h>
#include <vm/vm_kern.h>
#include <vm/vm_extern.h>

struct vm_map kernel_map;
struct vm_map clean_map;
struct vm_map buffer_map;

/*
 *      kmem_alloc_pageable:
 *
 *      Allocate pageable memory to the kernel's address map.
 *      "map" must be kernel_map or a submap of kernel_map.
 */
vm_offset_t
kmem_alloc_pageable(vm_map_t map, vm_size_t size)
{
        vm_offset_t addr;
        int result;

        size = round_page(size);
        addr = vm_map_min(map);
        result = vm_map_find(map, NULL, (vm_offset_t) 0,
                             &addr, size,
                             TRUE, 
                             VM_MAPTYPE_NORMAL,
                             VM_PROT_ALL, VM_PROT_ALL,
                             0);
        if (result != KERN_SUCCESS) {
                return (0);
        }
        return (addr);
}

/*
 *      kmem_alloc_nofault:
 *
 *      Same as kmem_alloc_pageable, except that it create a nofault entry.
 */
vm_offset_t
kmem_alloc_nofault(vm_map_t map, vm_size_t size)
{
        vm_offset_t addr;
        int result;

        size = round_page(size);
        addr = vm_map_min(map);
        result = vm_map_find(map, NULL, (vm_offset_t) 0,
                             &addr, size,
                             TRUE,
                             VM_MAPTYPE_NORMAL,
                             VM_PROT_ALL, VM_PROT_ALL,
                             MAP_NOFAULT);
        if (result != KERN_SUCCESS) {
                return (0);
        }
        return (addr);
}

/*
 *      Allocate wired-down memory in the kernel's address map
 *      or a submap.
 */
vm_offset_t
kmem_alloc3(vm_map_t map, vm_size_t size, int kmflags)
{
        vm_offset_t addr;
        vm_offset_t i;
        int count;

        size = round_page(size);

        if (kmflags & KM_KRESERVE)
                count = vm_map_entry_kreserve(MAP_RESERVE_COUNT);
        else
                count = vm_map_entry_reserve(MAP_RESERVE_COUNT);

        /*
         * Use the kernel object for wired-down kernel pages. Assume that no
         * region of the kernel object is referenced more than once.
         *
         * Locate sufficient space in the map.  This will give us the final
         * virtual address for the new memory, and thus will tell us the
         * offset within the kernel map.
         */
        vm_map_lock(map);
        if (vm_map_findspace(map, vm_map_min(map), size, 1, &addr)) {
                vm_map_unlock(map);
                if (kmflags & KM_KRESERVE)
                        vm_map_entry_krelease(count);
                else
                        vm_map_entry_release(count);
                return (0);
        }
        vm_object_reference(&kernel_object);
        vm_map_insert(map, &count,
                      &kernel_object, addr, addr, addr + size,
                      VM_MAPTYPE_NORMAL,
                      VM_PROT_ALL, VM_PROT_ALL,
                      0);
        vm_map_unlock(map);
        if (kmflags & KM_KRESERVE)
                vm_map_entry_krelease(count);
        else
                vm_map_entry_release(count);

        /*
         * Guarantee that there are pages already in this object before
         * calling vm_map_wire.  This is to prevent the following
         * scenario:
         *
         * 1) Threads have swapped out, so that there is a pager for the
         * kernel_object. 2) The kmsg zone is empty, and so we are
         * kmem_allocing a new page for it. 3) vm_map_wire calls vm_fault;
         * there is no page, but there is a pager, so we call
         * pager_data_request.  But the kmsg zone is empty, so we must
         * kmem_alloc. 4) goto 1 5) Even if the kmsg zone is not empty: when
         * we get the data back from the pager, it will be (very stale)
         * non-zero data.  kmem_alloc is defined to return zero-filled memory.
         *
         * We're intentionally not activating the pages we allocate to prevent a
         * race with page-out.  vm_map_wire will wire the pages.
         */

        for (i = 0; i < size; i += PAGE_SIZE) {
                vm_page_t mem;

                mem = vm_page_grab(&kernel_object, OFF_TO_IDX(addr + i),
                            VM_ALLOC_ZERO | VM_ALLOC_NORMAL | VM_ALLOC_RETRY);
                if ((mem->flags & PG_ZERO) == 0)
                        vm_page_zero_fill(mem);
                mem->valid = VM_PAGE_BITS_ALL;
                vm_page_flag_clear(mem, PG_ZERO);
                vm_page_wakeup(mem);
        }

        /*
         * And finally, mark the data as non-pageable.
         */

        vm_map_wire(map, (vm_offset_t) addr, addr + size, kmflags);

        return (addr);
}

/*
 *      kmem_free:
 *
 *      Release a region of kernel virtual memory allocated
 *      with kmem_alloc, and return the physical pages
 *      associated with that region.
 *
 *      This routine may not block on kernel maps.
 */
void
kmem_free(vm_map_t map, vm_offset_t addr, vm_size_t size)
{
        vm_map_remove(map, trunc_page(addr), round_page(addr + size));
}

/*
 *      kmem_suballoc:
 *
 *      Used to break a system map into smaller maps, usually to reduce
 *      contention and to provide large KVA spaces for subsystems like the
 *      buffer cache.
 *
 *      parent          Map to take range from
 *      result  
 *      size            Size of range to find
 *      min, max        Returned endpoints of map
 *      pageable        Can the region be paged
 */
void
kmem_suballoc(vm_map_t parent, vm_map_t result,
              vm_offset_t *min, vm_offset_t *max, vm_size_t size)
{
        int ret;

        size = round_page(size);

        *min = (vm_offset_t) vm_map_min(parent);
        ret = vm_map_find(parent, NULL, (vm_offset_t) 0,
                          min, size,
                          TRUE,
                          VM_MAPTYPE_UNSPECIFIED,
                          VM_PROT_ALL, VM_PROT_ALL,
                          0);
        if (ret != KERN_SUCCESS) {
                kprintf("kmem_suballoc: bad status return of %d.\n", ret);
                panic("kmem_suballoc");
        }
        *max = *min + size;
        pmap_reference(vm_map_pmap(parent));
        vm_map_init(result, *min, *max, vm_map_pmap(parent));
        if ((ret = vm_map_submap(parent, *min, *max, result)) != KERN_SUCCESS)
                panic("kmem_suballoc: unable to change range to submap");
}

/*
 *      kmem_alloc_wait:
 *
 *      Allocates pageable memory from a sub-map of the kernel.  If the submap
 *      has no room, the caller sleeps waiting for more memory in the submap.
 *
 *      This routine may block.
 */

vm_offset_t
kmem_alloc_wait(vm_map_t map, vm_size_t size)
{
        vm_offset_t addr;
        int count;

        size = round_page(size);

        count = vm_map_entry_reserve(MAP_RESERVE_COUNT);

        for (;;) {
                /*
                 * To make this work for more than one map, use the map's lock
                 * to lock out sleepers/wakers.
                 */
                vm_map_lock(map);
                if (vm_map_findspace(map, vm_map_min(map), size, 1, &addr) == 0)
                        break;
                /* no space now; see if we can ever get space */
                if (vm_map_max(map) - vm_map_min(map) < size) {
                        vm_map_entry_release(count);
                        vm_map_unlock(map);
                        return (0);
                }
                vm_map_unlock(map);
                tsleep(map, 0, "kmaw", 0);
        }
        vm_map_insert(map, &count,
                      NULL, (vm_offset_t) 0,
                      addr, addr + size,
                      VM_MAPTYPE_NORMAL,
                      VM_PROT_ALL, VM_PROT_ALL,
                      0);
        vm_map_unlock(map);
        vm_map_entry_release(count);
        return (addr);
}

/*
 *      kmem_free_wakeup:
 *
 *      Returns memory to a submap of the kernel, and wakes up any processes
 *      waiting for memory in that map.
 */
void
kmem_free_wakeup(vm_map_t map, vm_offset_t addr, vm_size_t size)
{
        int count;

        count = vm_map_entry_reserve(MAP_RESERVE_COUNT);
        vm_map_lock(map);
        vm_map_delete(map, trunc_page(addr), round_page(addr + size), &count);
        wakeup(map);
        vm_map_unlock(map);
        vm_map_entry_release(count);
}

/*
 *      kmem_init:
 *
 *      Create the kernel_map and insert mappings to cover areas already
 *      allocated or reserved thus far.  That is, the area (KvaStart,start)
 *      and (end,KvaEnd) must be marked as allocated.
 *
 *      We could use a min_offset of 0 instead of KvaStart, but since the
 *      min_offset is not used for any calculations other then a bounds check
 *      it does not effect readability.  KvaStart is more appropriate.
 *
 *      Depend on the zalloc bootstrap cache to get our vm_map_entry_t.
 */
void
kmem_init(vm_offset_t start, vm_offset_t end)
{
        vm_map_t m;
        int count;

        m = vm_map_create(&kernel_map, &kernel_pmap, KvaStart, KvaEnd);
        vm_map_lock(m);
        /* N.B.: cannot use kgdb to debug, starting with this assignment ... */
        m->system_map = 1;
        count = vm_map_entry_reserve(MAP_RESERVE_COUNT);
        if (KvaStart != start) {
                vm_map_insert(m, &count, NULL, (vm_offset_t) 0,
                              KvaStart, start,
                              VM_MAPTYPE_NORMAL,
                              VM_PROT_ALL, VM_PROT_ALL,
                              0);
        }
        if (KvaEnd != end) {
                vm_map_insert(m, &count, NULL, (vm_offset_t) 0,
                              end, KvaEnd,
                              VM_MAPTYPE_NORMAL,
                              VM_PROT_ALL, VM_PROT_ALL,
                              0);
        }
        /* ... and ending with the completion of the above `insert' */
        vm_map_unlock(m);
        vm_map_entry_release(count);
}

static int
kvm_size(SYSCTL_HANDLER_ARGS)
{
        unsigned long ksize = KvaSize;

        return sysctl_handle_long(oidp, &ksize, 0, req);
}
SYSCTL_PROC(_vm, OID_AUTO, kvm_size, CTLTYPE_LONG|CTLFLAG_RD,
    0, 0, kvm_size, "IU", "Size of KVM");
 
static int
kvm_free(SYSCTL_HANDLER_ARGS)
{
        unsigned long kfree = virtual_end - kernel_vm_end;

        return sysctl_handle_long(oidp, &kfree, 0, req);
}
SYSCTL_PROC(_vm, OID_AUTO, kvm_free, CTLTYPE_LONG|CTLFLAG_RD,
    0, 0, kvm_free, "IU", "Amount of KVM free");