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freebsd-nq/sys/vm/vm_reserv.c
Alan Cox 8b5e1472d2 Utilize pmap_enter(..., psind=1) in vm_fault_soft_fast() on amd64. (The 
Differential Revision discusses the benefits of this change.)

Add a function, vm_reserv_to_superpage(), that returns the superpage
containing the specified base page.

Reviewed by:	kib, markj
Tested by:	pho
MFC after:	10 days
Differential Revision:	https://reviews.freebsd.org/D11556
2017-07-23 16:28:13 +00:00

1139 lines
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/*-
* Copyright (c) 2002-2006 Rice University
* Copyright (c) 2007-2011 Alan L. Cox <alc@cs.rice.edu>
* All rights reserved.
*
* This software was developed for the FreeBSD Project by Alan L. Cox,
* Olivier Crameri, Peter Druschel, Sitaram Iyer, and Juan Navarro.
*
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 COPYRIGHT
* HOLDERS 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.
*/
/*
* Superpage reservation management module
*
* Any external functions defined by this module are only to be used by the
* virtual memory system.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_vm.h"
#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mutex.h>
#include <sys/queue.h>
#include <sys/rwlock.h>
#include <sys/sbuf.h>
#include <sys/sysctl.h>
#include <sys/systm.h>
#include <sys/vmmeter.h>
#include <vm/vm.h>
#include <vm/vm_param.h>
#include <vm/vm_object.h>
#include <vm/vm_page.h>
#include <vm/vm_phys.h>
#include <vm/vm_radix.h>
#include <vm/vm_reserv.h>
/*
* The reservation system supports the speculative allocation of large physical
* pages ("superpages"). Speculative allocation enables the fully automatic
* utilization of superpages by the virtual memory system. In other words, no
* programmatic directives are required to use superpages.
*/
#if VM_NRESERVLEVEL > 0
/*
* The number of small pages that are contained in a level 0 reservation
*/
#define VM_LEVEL_0_NPAGES (1 << VM_LEVEL_0_ORDER)
/*
* The number of bits by which a physical address is shifted to obtain the
* reservation number
*/
#define VM_LEVEL_0_SHIFT (VM_LEVEL_0_ORDER + PAGE_SHIFT)
/*
* The size of a level 0 reservation in bytes
*/
#define VM_LEVEL_0_SIZE (1 << VM_LEVEL_0_SHIFT)
/*
* Computes the index of the small page underlying the given (object, pindex)
* within the reservation's array of small pages.
*/
#define VM_RESERV_INDEX(object, pindex) \
(((object)->pg_color + (pindex)) & (VM_LEVEL_0_NPAGES - 1))
/*
* The size of a population map entry
*/
typedef u_long popmap_t;
/*
* The number of bits in a population map entry
*/
#define NBPOPMAP (NBBY * sizeof(popmap_t))
/*
* The number of population map entries in a reservation
*/
#define NPOPMAP howmany(VM_LEVEL_0_NPAGES, NBPOPMAP)
/*
* Clear a bit in the population map.
*/
static __inline void
popmap_clear(popmap_t popmap[], int i)
{
popmap[i / NBPOPMAP] &= ~(1UL << (i % NBPOPMAP));
}
/*
* Set a bit in the population map.
*/
static __inline void
popmap_set(popmap_t popmap[], int i)
{
popmap[i / NBPOPMAP] |= 1UL << (i % NBPOPMAP);
}
/*
* Is a bit in the population map clear?
*/
static __inline boolean_t
popmap_is_clear(popmap_t popmap[], int i)
{
return ((popmap[i / NBPOPMAP] & (1UL << (i % NBPOPMAP))) == 0);
}
/*
* Is a bit in the population map set?
*/
static __inline boolean_t
popmap_is_set(popmap_t popmap[], int i)
{
return ((popmap[i / NBPOPMAP] & (1UL << (i % NBPOPMAP))) != 0);
}
/*
* The reservation structure
*
* A reservation structure is constructed whenever a large physical page is
* speculatively allocated to an object. The reservation provides the small
* physical pages for the range [pindex, pindex + VM_LEVEL_0_NPAGES) of offsets
* within that object. The reservation's "popcnt" tracks the number of these
* small physical pages that are in use at any given time. When and if the
* reservation is not fully utilized, it appears in the queue of partially
* populated reservations. The reservation always appears on the containing
* object's list of reservations.
*
* A partially populated reservation can be broken and reclaimed at any time.
*/
struct vm_reserv {
TAILQ_ENTRY(vm_reserv) partpopq;
LIST_ENTRY(vm_reserv) objq;
vm_object_t object; /* containing object */
vm_pindex_t pindex; /* offset within object */
vm_page_t pages; /* first page of a superpage */
int popcnt; /* # of pages in use */
char inpartpopq;
popmap_t popmap[NPOPMAP]; /* bit vector of used pages */
};
/*
* The reservation array
*
* This array is analoguous in function to vm_page_array. It differs in the
* respect that it may contain a greater number of useful reservation
* structures than there are (physical) superpages. These "invalid"
* reservation structures exist to trade-off space for time in the
* implementation of vm_reserv_from_page(). Invalid reservation structures are
* distinguishable from "valid" reservation structures by inspecting the
* reservation's "pages" field. Invalid reservation structures have a NULL
* "pages" field.
*
* vm_reserv_from_page() maps a small (physical) page to an element of this
* array by computing a physical reservation number from the page's physical
* address. The physical reservation number is used as the array index.
*
* An "active" reservation is a valid reservation structure that has a non-NULL
* "object" field and a non-zero "popcnt" field. In other words, every active
* reservation belongs to a particular object. Moreover, every active
* reservation has an entry in the containing object's list of reservations.
*/
static vm_reserv_t vm_reserv_array;
/*
* The partially populated reservation queue
*
* This queue enables the fast recovery of an unused free small page from a
* partially populated reservation. The reservation at the head of this queue
* is the least recently changed, partially populated reservation.
*
* Access to this queue is synchronized by the free page queue lock.
*/
static TAILQ_HEAD(, vm_reserv) vm_rvq_partpop =
TAILQ_HEAD_INITIALIZER(vm_rvq_partpop);
static SYSCTL_NODE(_vm, OID_AUTO, reserv, CTLFLAG_RD, 0, "Reservation Info");
static long vm_reserv_broken;
SYSCTL_LONG(_vm_reserv, OID_AUTO, broken, CTLFLAG_RD,
&vm_reserv_broken, 0, "Cumulative number of broken reservations");
static long vm_reserv_freed;
SYSCTL_LONG(_vm_reserv, OID_AUTO, freed, CTLFLAG_RD,
&vm_reserv_freed, 0, "Cumulative number of freed reservations");
static int sysctl_vm_reserv_fullpop(SYSCTL_HANDLER_ARGS);
SYSCTL_PROC(_vm_reserv, OID_AUTO, fullpop, CTLTYPE_INT | CTLFLAG_RD, NULL, 0,
sysctl_vm_reserv_fullpop, "I", "Current number of full reservations");
static int sysctl_vm_reserv_partpopq(SYSCTL_HANDLER_ARGS);
SYSCTL_OID(_vm_reserv, OID_AUTO, partpopq, CTLTYPE_STRING | CTLFLAG_RD, NULL, 0,
sysctl_vm_reserv_partpopq, "A", "Partially populated reservation queues");
static long vm_reserv_reclaimed;
SYSCTL_LONG(_vm_reserv, OID_AUTO, reclaimed, CTLFLAG_RD,
&vm_reserv_reclaimed, 0, "Cumulative number of reclaimed reservations");
static void vm_reserv_break(vm_reserv_t rv, vm_page_t m);
static void vm_reserv_depopulate(vm_reserv_t rv, int index);
static vm_reserv_t vm_reserv_from_page(vm_page_t m);
static boolean_t vm_reserv_has_pindex(vm_reserv_t rv,
vm_pindex_t pindex);
static void vm_reserv_populate(vm_reserv_t rv, int index);
static void vm_reserv_reclaim(vm_reserv_t rv);
/*
* Returns the current number of full reservations.
*
* Since the number of full reservations is computed without acquiring the
* free page queue lock, the returned value may be inexact.
*/
static int
sysctl_vm_reserv_fullpop(SYSCTL_HANDLER_ARGS)
{
vm_paddr_t paddr;
struct vm_phys_seg *seg;
vm_reserv_t rv;
int fullpop, segind;
fullpop = 0;
for (segind = 0; segind < vm_phys_nsegs; segind++) {
seg = &vm_phys_segs[segind];
paddr = roundup2(seg->start, VM_LEVEL_0_SIZE);
while (paddr + VM_LEVEL_0_SIZE <= seg->end) {
rv = &vm_reserv_array[paddr >> VM_LEVEL_0_SHIFT];
fullpop += rv->popcnt == VM_LEVEL_0_NPAGES;
paddr += VM_LEVEL_0_SIZE;
}
}
return (sysctl_handle_int(oidp, &fullpop, 0, req));
}
/*
* Describes the current state of the partially populated reservation queue.
*/
static int
sysctl_vm_reserv_partpopq(SYSCTL_HANDLER_ARGS)
{
struct sbuf sbuf;
vm_reserv_t rv;
int counter, error, level, unused_pages;
error = sysctl_wire_old_buffer(req, 0);
if (error != 0)
return (error);
sbuf_new_for_sysctl(&sbuf, NULL, 128, req);
sbuf_printf(&sbuf, "\nLEVEL SIZE NUMBER\n\n");
for (level = -1; level <= VM_NRESERVLEVEL - 2; level++) {
counter = 0;
unused_pages = 0;
mtx_lock(&vm_page_queue_free_mtx);
TAILQ_FOREACH(rv, &vm_rvq_partpop/*[level]*/, partpopq) {
counter++;
unused_pages += VM_LEVEL_0_NPAGES - rv->popcnt;
}
mtx_unlock(&vm_page_queue_free_mtx);
sbuf_printf(&sbuf, "%5d: %6dK, %6d\n", level,
unused_pages * ((int)PAGE_SIZE / 1024), counter);
}
error = sbuf_finish(&sbuf);
sbuf_delete(&sbuf);
return (error);
}
/*
* Reduces the given reservation's population count. If the population count
* becomes zero, the reservation is destroyed. Additionally, moves the
* reservation to the tail of the partially populated reservation queue if the
* population count is non-zero.
*
* The free page queue lock must be held.
*/
static void
vm_reserv_depopulate(vm_reserv_t rv, int index)
{
mtx_assert(&vm_page_queue_free_mtx, MA_OWNED);
KASSERT(rv->object != NULL,
("vm_reserv_depopulate: reserv %p is free", rv));
KASSERT(popmap_is_set(rv->popmap, index),
("vm_reserv_depopulate: reserv %p's popmap[%d] is clear", rv,
index));
KASSERT(rv->popcnt > 0,
("vm_reserv_depopulate: reserv %p's popcnt is corrupted", rv));
if (rv->inpartpopq) {
TAILQ_REMOVE(&vm_rvq_partpop, rv, partpopq);
rv->inpartpopq = FALSE;
} else {
KASSERT(rv->pages->psind == 1,
("vm_reserv_depopulate: reserv %p is already demoted",
rv));
rv->pages->psind = 0;
}
popmap_clear(rv->popmap, index);
rv->popcnt--;
if (rv->popcnt == 0) {
LIST_REMOVE(rv, objq);
rv->object = NULL;
vm_phys_free_pages(rv->pages, VM_LEVEL_0_ORDER);
vm_reserv_freed++;
} else {
rv->inpartpopq = TRUE;
TAILQ_INSERT_TAIL(&vm_rvq_partpop, rv, partpopq);
}
}
/*
* Returns the reservation to which the given page might belong.
*/
static __inline vm_reserv_t
vm_reserv_from_page(vm_page_t m)
{
return (&vm_reserv_array[VM_PAGE_TO_PHYS(m) >> VM_LEVEL_0_SHIFT]);
}
/*
* Returns TRUE if the given reservation contains the given page index and
* FALSE otherwise.
*/
static __inline boolean_t
vm_reserv_has_pindex(vm_reserv_t rv, vm_pindex_t pindex)
{
return (((pindex - rv->pindex) & ~(VM_LEVEL_0_NPAGES - 1)) == 0);
}
/*
* Increases the given reservation's population count. Moves the reservation
* to the tail of the partially populated reservation queue.
*
* The free page queue must be locked.
*/
static void
vm_reserv_populate(vm_reserv_t rv, int index)
{
mtx_assert(&vm_page_queue_free_mtx, MA_OWNED);
KASSERT(rv->object != NULL,
("vm_reserv_populate: reserv %p is free", rv));
KASSERT(popmap_is_clear(rv->popmap, index),
("vm_reserv_populate: reserv %p's popmap[%d] is set", rv,
index));
KASSERT(rv->popcnt < VM_LEVEL_0_NPAGES,
("vm_reserv_populate: reserv %p is already full", rv));
KASSERT(rv->pages->psind == 0,
("vm_reserv_populate: reserv %p is already promoted", rv));
if (rv->inpartpopq) {
TAILQ_REMOVE(&vm_rvq_partpop, rv, partpopq);
rv->inpartpopq = FALSE;
}
popmap_set(rv->popmap, index);
rv->popcnt++;
if (rv->popcnt < VM_LEVEL_0_NPAGES) {
rv->inpartpopq = TRUE;
TAILQ_INSERT_TAIL(&vm_rvq_partpop, rv, partpopq);
} else
rv->pages->psind = 1;
}
/*
* Allocates a contiguous set of physical pages of the given size "npages"
* from existing or newly created reservations. All of the physical pages
* must be at or above the given physical address "low" and below the given
* physical address "high". The given value "alignment" determines the
* alignment of the first physical page in the set. If the given value
* "boundary" is non-zero, then the set of physical pages cannot cross any
* physical address boundary that is a multiple of that value. Both
* "alignment" and "boundary" must be a power of two.
*
* The page "mpred" must immediately precede the offset "pindex" within the
* specified object.
*
* The object and free page queue must be locked.
*/
vm_page_t
vm_reserv_alloc_contig(vm_object_t object, vm_pindex_t pindex, u_long npages,
vm_paddr_t low, vm_paddr_t high, u_long alignment, vm_paddr_t boundary,
vm_page_t mpred)
{
vm_paddr_t pa, size;
vm_page_t m, m_ret, msucc;
vm_pindex_t first, leftcap, rightcap;
vm_reserv_t rv;
u_long allocpages, maxpages, minpages;
int i, index, n;
mtx_assert(&vm_page_queue_free_mtx, MA_OWNED);
VM_OBJECT_ASSERT_WLOCKED(object);
KASSERT(npages != 0, ("vm_reserv_alloc_contig: npages is 0"));
/*
* Is a reservation fundamentally impossible?
*/
if (pindex < VM_RESERV_INDEX(object, pindex) ||
pindex + npages > object->size)
return (NULL);
/*
* All reservations of a particular size have the same alignment.
* Assuming that the first page is allocated from a reservation, the
* least significant bits of its physical address can be determined
* from its offset from the beginning of the reservation and the size
* of the reservation.
*
* Could the specified index within a reservation of the smallest
* possible size satisfy the alignment and boundary requirements?
*/
pa = VM_RESERV_INDEX(object, pindex) << PAGE_SHIFT;
if ((pa & (alignment - 1)) != 0)
return (NULL);
size = npages << PAGE_SHIFT;
if (((pa ^ (pa + size - 1)) & ~(boundary - 1)) != 0)
return (NULL);
/*
* Look for an existing reservation.
*/
if (mpred != NULL) {
KASSERT(mpred->object == object,
("vm_reserv_alloc_contig: object doesn't contain mpred"));
KASSERT(mpred->pindex < pindex,
("vm_reserv_alloc_contig: mpred doesn't precede pindex"));
rv = vm_reserv_from_page(mpred);
if (rv->object == object && vm_reserv_has_pindex(rv, pindex))
goto found;
msucc = TAILQ_NEXT(mpred, listq);
} else
msucc = TAILQ_FIRST(&object->memq);
if (msucc != NULL) {
KASSERT(msucc->pindex > pindex,
("vm_reserv_alloc_contig: msucc doesn't succeed pindex"));
rv = vm_reserv_from_page(msucc);
if (rv->object == object && vm_reserv_has_pindex(rv, pindex))
goto found;
}
/*
* Could at least one reservation fit between the first index to the
* left that can be used ("leftcap") and the first index to the right
* that cannot be used ("rightcap")?
*/
first = pindex - VM_RESERV_INDEX(object, pindex);
if (mpred != NULL) {
if ((rv = vm_reserv_from_page(mpred))->object != object)
leftcap = mpred->pindex + 1;
else
leftcap = rv->pindex + VM_LEVEL_0_NPAGES;
if (leftcap > first)
return (NULL);
}
minpages = VM_RESERV_INDEX(object, pindex) + npages;
maxpages = roundup2(minpages, VM_LEVEL_0_NPAGES);
allocpages = maxpages;
if (msucc != NULL) {
if ((rv = vm_reserv_from_page(msucc))->object != object)
rightcap = msucc->pindex;
else
rightcap = rv->pindex;
if (first + maxpages > rightcap) {
if (maxpages == VM_LEVEL_0_NPAGES)
return (NULL);
/*
* At least one reservation will fit between "leftcap"
* and "rightcap". However, a reservation for the
* last of the requested pages will not fit. Reduce
* the size of the upcoming allocation accordingly.
*/
allocpages = minpages;
}
}
/*
* Would the last new reservation extend past the end of the object?
*/
if (first + maxpages > object->size) {
/*
* Don't allocate the last new reservation if the object is a
* vnode or backed by another object that is a vnode.
*/
if (object->type == OBJT_VNODE ||
(object->backing_object != NULL &&
object->backing_object->type == OBJT_VNODE)) {
if (maxpages == VM_LEVEL_0_NPAGES)
return (NULL);
allocpages = minpages;
}
/* Speculate that the object may grow. */
}
/*
* Allocate the physical pages. The alignment and boundary specified
* for this allocation may be different from the alignment and
* boundary specified for the requested pages. For instance, the
* specified index may not be the first page within the first new
* reservation.
*/
m = vm_phys_alloc_contig(allocpages, low, high, ulmax(alignment,
VM_LEVEL_0_SIZE), boundary > VM_LEVEL_0_SIZE ? boundary : 0);
if (m == NULL)
return (NULL);
/*
* The allocated physical pages always begin at a reservation
* boundary, but they do not always end at a reservation boundary.
* Initialize every reservation that is completely covered by the
* allocated physical pages.
*/
m_ret = NULL;
index = VM_RESERV_INDEX(object, pindex);
do {
rv = vm_reserv_from_page(m);
KASSERT(rv->pages == m,
("vm_reserv_alloc_contig: reserv %p's pages is corrupted",
rv));
KASSERT(rv->object == NULL,
("vm_reserv_alloc_contig: reserv %p isn't free", rv));
LIST_INSERT_HEAD(&object->rvq, rv, objq);
rv->object = object;
rv->pindex = first;
KASSERT(rv->popcnt == 0,
("vm_reserv_alloc_contig: reserv %p's popcnt is corrupted",
rv));
KASSERT(!rv->inpartpopq,
("vm_reserv_alloc_contig: reserv %p's inpartpopq is TRUE",
rv));
for (i = 0; i < NPOPMAP; i++)
KASSERT(rv->popmap[i] == 0,
("vm_reserv_alloc_contig: reserv %p's popmap is corrupted",
rv));
n = ulmin(VM_LEVEL_0_NPAGES - index, npages);
for (i = 0; i < n; i++)
vm_reserv_populate(rv, index + i);
npages -= n;
if (m_ret == NULL) {
m_ret = &rv->pages[index];
index = 0;
}
m += VM_LEVEL_0_NPAGES;
first += VM_LEVEL_0_NPAGES;
allocpages -= VM_LEVEL_0_NPAGES;
} while (allocpages >= VM_LEVEL_0_NPAGES);
return (m_ret);
/*
* Found a matching reservation.
*/
found:
index = VM_RESERV_INDEX(object, pindex);
/* Does the allocation fit within the reservation? */
if (index + npages > VM_LEVEL_0_NPAGES)
return (NULL);
m = &rv->pages[index];
pa = VM_PAGE_TO_PHYS(m);
if (pa < low || pa + size > high || (pa & (alignment - 1)) != 0 ||
((pa ^ (pa + size - 1)) & ~(boundary - 1)) != 0)
return (NULL);
/* Handle vm_page_rename(m, new_object, ...). */
for (i = 0; i < npages; i++)
if (popmap_is_set(rv->popmap, index + i))
return (NULL);
for (i = 0; i < npages; i++)
vm_reserv_populate(rv, index + i);
return (m);
}
/*
* Allocates a page from an existing or newly created reservation.
*
* The page "mpred" must immediately precede the offset "pindex" within the
* specified object.
*
* The object and free page queue must be locked.
*/
vm_page_t
vm_reserv_alloc_page(vm_object_t object, vm_pindex_t pindex, vm_page_t mpred)
{
vm_page_t m, msucc;
vm_pindex_t first, leftcap, rightcap;
vm_reserv_t rv;
int i, index;
mtx_assert(&vm_page_queue_free_mtx, MA_OWNED);
VM_OBJECT_ASSERT_WLOCKED(object);
/*
* Is a reservation fundamentally impossible?
*/
if (pindex < VM_RESERV_INDEX(object, pindex) ||
pindex >= object->size)
return (NULL);
/*
* Look for an existing reservation.
*/
if (mpred != NULL) {
KASSERT(mpred->object == object,
("vm_reserv_alloc_page: object doesn't contain mpred"));
KASSERT(mpred->pindex < pindex,
("vm_reserv_alloc_page: mpred doesn't precede pindex"));
rv = vm_reserv_from_page(mpred);
if (rv->object == object && vm_reserv_has_pindex(rv, pindex))
goto found;
msucc = TAILQ_NEXT(mpred, listq);
} else
msucc = TAILQ_FIRST(&object->memq);
if (msucc != NULL) {
KASSERT(msucc->pindex > pindex,
("vm_reserv_alloc_page: msucc doesn't succeed pindex"));
rv = vm_reserv_from_page(msucc);
if (rv->object == object && vm_reserv_has_pindex(rv, pindex))
goto found;
}
/*
* Could a reservation fit between the first index to the left that
* can be used and the first index to the right that cannot be used?
*/
first = pindex - VM_RESERV_INDEX(object, pindex);
if (mpred != NULL) {
if ((rv = vm_reserv_from_page(mpred))->object != object)
leftcap = mpred->pindex + 1;
else
leftcap = rv->pindex + VM_LEVEL_0_NPAGES;
if (leftcap > first)
return (NULL);
}
if (msucc != NULL) {
if ((rv = vm_reserv_from_page(msucc))->object != object)
rightcap = msucc->pindex;
else
rightcap = rv->pindex;
if (first + VM_LEVEL_0_NPAGES > rightcap)
return (NULL);
}
/*
* Would a new reservation extend past the end of the object?
*/
if (first + VM_LEVEL_0_NPAGES > object->size) {
/*
* Don't allocate a new reservation if the object is a vnode or
* backed by another object that is a vnode.
*/
if (object->type == OBJT_VNODE ||
(object->backing_object != NULL &&
object->backing_object->type == OBJT_VNODE))
return (NULL);
/* Speculate that the object may grow. */
}
/*
* Allocate and populate the new reservation.
*/
m = vm_phys_alloc_pages(VM_FREEPOOL_DEFAULT, VM_LEVEL_0_ORDER);
if (m == NULL)
return (NULL);
rv = vm_reserv_from_page(m);
KASSERT(rv->pages == m,
("vm_reserv_alloc_page: reserv %p's pages is corrupted", rv));
KASSERT(rv->object == NULL,
("vm_reserv_alloc_page: reserv %p isn't free", rv));
LIST_INSERT_HEAD(&object->rvq, rv, objq);
rv->object = object;
rv->pindex = first;
KASSERT(rv->popcnt == 0,
("vm_reserv_alloc_page: reserv %p's popcnt is corrupted", rv));
KASSERT(!rv->inpartpopq,
("vm_reserv_alloc_page: reserv %p's inpartpopq is TRUE", rv));
for (i = 0; i < NPOPMAP; i++)
KASSERT(rv->popmap[i] == 0,
("vm_reserv_alloc_page: reserv %p's popmap is corrupted",
rv));
index = VM_RESERV_INDEX(object, pindex);
vm_reserv_populate(rv, index);
return (&rv->pages[index]);
/*
* Found a matching reservation.
*/
found:
index = VM_RESERV_INDEX(object, pindex);
m = &rv->pages[index];
/* Handle vm_page_rename(m, new_object, ...). */
if (popmap_is_set(rv->popmap, index))
return (NULL);
vm_reserv_populate(rv, index);
return (m);
}
/*
* Breaks the given reservation. Except for the specified free page, all free
* pages in the reservation are returned to the physical memory allocator.
* The reservation's population count and map are reset to their initial
* state.
*
* The given reservation must not be in the partially populated reservation
* queue. The free page queue lock must be held.
*/
static void
vm_reserv_break(vm_reserv_t rv, vm_page_t m)
{
int begin_zeroes, hi, i, lo;
mtx_assert(&vm_page_queue_free_mtx, MA_OWNED);
KASSERT(rv->object != NULL,
("vm_reserv_break: reserv %p is free", rv));
KASSERT(!rv->inpartpopq,
("vm_reserv_break: reserv %p's inpartpopq is TRUE", rv));
LIST_REMOVE(rv, objq);
rv->object = NULL;
if (m != NULL) {
/*
* Since the reservation is being broken, there is no harm in
* abusing the population map to stop "m" from being returned
* to the physical memory allocator.
*/
i = m - rv->pages;
KASSERT(popmap_is_clear(rv->popmap, i),
("vm_reserv_break: reserv %p's popmap is corrupted", rv));
popmap_set(rv->popmap, i);
rv->popcnt++;
}
i = hi = 0;
do {
/* Find the next 0 bit. Any previous 0 bits are < "hi". */
lo = ffsl(~(((1UL << hi) - 1) | rv->popmap[i]));
if (lo == 0) {
/* Redundantly clears bits < "hi". */
rv->popmap[i] = 0;
rv->popcnt -= NBPOPMAP - hi;
while (++i < NPOPMAP) {
lo = ffsl(~rv->popmap[i]);
if (lo == 0) {
rv->popmap[i] = 0;
rv->popcnt -= NBPOPMAP;
} else
break;
}
if (i == NPOPMAP)
break;
hi = 0;
}
KASSERT(lo > 0, ("vm_reserv_break: lo is %d", lo));
/* Convert from ffsl() to ordinary bit numbering. */
lo--;
if (lo > 0) {
/* Redundantly clears bits < "hi". */
rv->popmap[i] &= ~((1UL << lo) - 1);
rv->popcnt -= lo - hi;
}
begin_zeroes = NBPOPMAP * i + lo;
/* Find the next 1 bit. */
do
hi = ffsl(rv->popmap[i]);
while (hi == 0 && ++i < NPOPMAP);
if (i != NPOPMAP)
/* Convert from ffsl() to ordinary bit numbering. */
hi--;
vm_phys_free_contig(&rv->pages[begin_zeroes], NBPOPMAP * i +
hi - begin_zeroes);
} while (i < NPOPMAP);
KASSERT(rv->popcnt == 0,
("vm_reserv_break: reserv %p's popcnt is corrupted", rv));
vm_reserv_broken++;
}
/*
* Breaks all reservations belonging to the given object.
*/
void
vm_reserv_break_all(vm_object_t object)
{
vm_reserv_t rv;
mtx_lock(&vm_page_queue_free_mtx);
while ((rv = LIST_FIRST(&object->rvq)) != NULL) {
KASSERT(rv->object == object,
("vm_reserv_break_all: reserv %p is corrupted", rv));
if (rv->inpartpopq) {
TAILQ_REMOVE(&vm_rvq_partpop, rv, partpopq);
rv->inpartpopq = FALSE;
}
vm_reserv_break(rv, NULL);
}
mtx_unlock(&vm_page_queue_free_mtx);
}
/*
* Frees the given page if it belongs to a reservation. Returns TRUE if the
* page is freed and FALSE otherwise.
*
* The free page queue lock must be held.
*/
boolean_t
vm_reserv_free_page(vm_page_t m)
{
vm_reserv_t rv;
mtx_assert(&vm_page_queue_free_mtx, MA_OWNED);
rv = vm_reserv_from_page(m);
if (rv->object == NULL)
return (FALSE);
vm_reserv_depopulate(rv, m - rv->pages);
return (TRUE);
}
/*
* Initializes the reservation management system. Specifically, initializes
* the reservation array.
*
* Requires that vm_page_array and first_page are initialized!
*/
void
vm_reserv_init(void)
{
vm_paddr_t paddr;
struct vm_phys_seg *seg;
int segind;
/*
* Initialize the reservation array. Specifically, initialize the
* "pages" field for every element that has an underlying superpage.
*/
for (segind = 0; segind < vm_phys_nsegs; segind++) {
seg = &vm_phys_segs[segind];
paddr = roundup2(seg->start, VM_LEVEL_0_SIZE);
while (paddr + VM_LEVEL_0_SIZE <= seg->end) {
vm_reserv_array[paddr >> VM_LEVEL_0_SHIFT].pages =
PHYS_TO_VM_PAGE(paddr);
paddr += VM_LEVEL_0_SIZE;
}
}
}
/*
* Returns true if the given page belongs to a reservation and that page is
* free. Otherwise, returns false.
*/
bool
vm_reserv_is_page_free(vm_page_t m)
{
vm_reserv_t rv;
mtx_assert(&vm_page_queue_free_mtx, MA_OWNED);
rv = vm_reserv_from_page(m);
if (rv->object == NULL)
return (false);
return (popmap_is_clear(rv->popmap, m - rv->pages));
}
/*
* If the given page belongs to a reservation, returns the level of that
* reservation. Otherwise, returns -1.
*/
int
vm_reserv_level(vm_page_t m)
{
vm_reserv_t rv;
rv = vm_reserv_from_page(m);
return (rv->object != NULL ? 0 : -1);
}
/*
* Returns a reservation level if the given page belongs to a fully populated
* reservation and -1 otherwise.
*/
int
vm_reserv_level_iffullpop(vm_page_t m)
{
vm_reserv_t rv;
rv = vm_reserv_from_page(m);
return (rv->popcnt == VM_LEVEL_0_NPAGES ? 0 : -1);
}
/*
* Breaks the given partially populated reservation, releasing its free pages
* to the physical memory allocator.
*
* The free page queue lock must be held.
*/
static void
vm_reserv_reclaim(vm_reserv_t rv)
{
mtx_assert(&vm_page_queue_free_mtx, MA_OWNED);
KASSERT(rv->inpartpopq,
("vm_reserv_reclaim: reserv %p's inpartpopq is FALSE", rv));
TAILQ_REMOVE(&vm_rvq_partpop, rv, partpopq);
rv->inpartpopq = FALSE;
vm_reserv_break(rv, NULL);
vm_reserv_reclaimed++;
}
/*
* Breaks the reservation at the head of the partially populated reservation
* queue, releasing its free pages to the physical memory allocator. Returns
* TRUE if a reservation is broken and FALSE otherwise.
*
* The free page queue lock must be held.
*/
boolean_t
vm_reserv_reclaim_inactive(void)
{
vm_reserv_t rv;
mtx_assert(&vm_page_queue_free_mtx, MA_OWNED);
if ((rv = TAILQ_FIRST(&vm_rvq_partpop)) != NULL) {
vm_reserv_reclaim(rv);
return (TRUE);
}
return (FALSE);
}
/*
* Searches the partially populated reservation queue for the least recently
* changed reservation with free pages that satisfy the given request for
* contiguous physical memory. If a satisfactory reservation is found, it is
* broken. Returns TRUE if a reservation is broken and FALSE otherwise.
*
* The free page queue lock must be held.
*/
boolean_t
vm_reserv_reclaim_contig(u_long npages, vm_paddr_t low, vm_paddr_t high,
u_long alignment, vm_paddr_t boundary)
{
vm_paddr_t pa, size;
vm_reserv_t rv;
int hi, i, lo, low_index, next_free;
mtx_assert(&vm_page_queue_free_mtx, MA_OWNED);
if (npages > VM_LEVEL_0_NPAGES - 1)
return (FALSE);
size = npages << PAGE_SHIFT;
TAILQ_FOREACH(rv, &vm_rvq_partpop, partpopq) {
pa = VM_PAGE_TO_PHYS(&rv->pages[VM_LEVEL_0_NPAGES - 1]);
if (pa + PAGE_SIZE - size < low) {
/* This entire reservation is too low; go to next. */
continue;
}
pa = VM_PAGE_TO_PHYS(&rv->pages[0]);
if (pa + size > high) {
/* This entire reservation is too high; go to next. */
continue;
}
if (pa < low) {
/* Start the search for free pages at "low". */
low_index = (low + PAGE_MASK - pa) >> PAGE_SHIFT;
i = low_index / NBPOPMAP;
hi = low_index % NBPOPMAP;
} else
i = hi = 0;
do {
/* Find the next free page. */
lo = ffsl(~(((1UL << hi) - 1) | rv->popmap[i]));
while (lo == 0 && ++i < NPOPMAP)
lo = ffsl(~rv->popmap[i]);
if (i == NPOPMAP)
break;
/* Convert from ffsl() to ordinary bit numbering. */
lo--;
next_free = NBPOPMAP * i + lo;
pa = VM_PAGE_TO_PHYS(&rv->pages[next_free]);
KASSERT(pa >= low,
("vm_reserv_reclaim_contig: pa is too low"));
if (pa + size > high) {
/* The rest of this reservation is too high. */
break;
} else if ((pa & (alignment - 1)) != 0 ||
((pa ^ (pa + size - 1)) & ~(boundary - 1)) != 0) {
/*
* The current page doesn't meet the alignment
* and/or boundary requirements. Continue
* searching this reservation until the rest
* of its free pages are either excluded or
* exhausted.
*/
hi = lo + 1;
if (hi >= NBPOPMAP) {
hi = 0;
i++;
}
continue;
}
/* Find the next used page. */
hi = ffsl(rv->popmap[i] & ~((1UL << lo) - 1));
while (hi == 0 && ++i < NPOPMAP) {
if ((NBPOPMAP * i - next_free) * PAGE_SIZE >=
size) {
vm_reserv_reclaim(rv);
return (TRUE);
}
hi = ffsl(rv->popmap[i]);
}
/* Convert from ffsl() to ordinary bit numbering. */
if (i != NPOPMAP)
hi--;
if ((NBPOPMAP * i + hi - next_free) * PAGE_SIZE >=
size) {
vm_reserv_reclaim(rv);
return (TRUE);
}
} while (i < NPOPMAP);
}
return (FALSE);
}
/*
* Transfers the reservation underlying the given page to a new object.
*
* The object must be locked.
*/
void
vm_reserv_rename(vm_page_t m, vm_object_t new_object, vm_object_t old_object,
vm_pindex_t old_object_offset)
{
vm_reserv_t rv;
VM_OBJECT_ASSERT_WLOCKED(new_object);
rv = vm_reserv_from_page(m);
if (rv->object == old_object) {
mtx_lock(&vm_page_queue_free_mtx);
if (rv->object == old_object) {
LIST_REMOVE(rv, objq);
LIST_INSERT_HEAD(&new_object->rvq, rv, objq);
rv->object = new_object;
rv->pindex -= old_object_offset;
}
mtx_unlock(&vm_page_queue_free_mtx);
}
}
/*
* Returns the size (in bytes) of a reservation of the specified level.
*/
int
vm_reserv_size(int level)
{
switch (level) {
case 0:
return (VM_LEVEL_0_SIZE);
case -1:
return (PAGE_SIZE);
default:
return (0);
}
}
/*
* Allocates the virtual and physical memory required by the reservation
* management system's data structures, in particular, the reservation array.
*/
vm_paddr_t
vm_reserv_startup(vm_offset_t *vaddr, vm_paddr_t end, vm_paddr_t high_water)
{
vm_paddr_t new_end;
size_t size;
/*
* Calculate the size (in bytes) of the reservation array. Round up
* from "high_water" because every small page is mapped to an element
* in the reservation array based on its physical address. Thus, the
* number of elements in the reservation array can be greater than the
* number of superpages.
*/
size = howmany(high_water, VM_LEVEL_0_SIZE) * sizeof(struct vm_reserv);
/*
* Allocate and map the physical memory for the reservation array. The
* next available virtual address is returned by reference.
*/
new_end = end - round_page(size);
vm_reserv_array = (void *)(uintptr_t)pmap_map(vaddr, new_end, end,
VM_PROT_READ | VM_PROT_WRITE);
bzero(vm_reserv_array, size);
/*
* Return the next available physical address.
*/
return (new_end);
}
/*
* Returns the superpage containing the given page.
*/
vm_page_t
vm_reserv_to_superpage(vm_page_t m)
{
vm_reserv_t rv;
VM_OBJECT_ASSERT_LOCKED(m->object);
rv = vm_reserv_from_page(m);
return (rv->object == m->object && rv->popcnt == VM_LEVEL_0_NPAGES ?
rv->pages : NULL);
}
#endif /* VM_NRESERVLEVEL > 0 */
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