/
uvm_page.c
1926 lines (1651 loc) · 47 KB
/
uvm_page.c
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/* $NetBSD: uvm_page.c,v 1.200 2019/09/20 11:09:43 maxv 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. 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 <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: uvm_page.c,v 1.200 2019/09/20 11:09:43 maxv Exp $");
#include "opt_ddb.h"
#include "opt_uvm.h"
#include "opt_uvmhist.h"
#include "opt_readahead.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/sched.h>
#include <sys/kernel.h>
#include <sys/vnode.h>
#include <sys/proc.h>
#include <sys/atomic.h>
#include <sys/cpu.h>
#include <sys/extent.h>
#include <uvm/uvm.h>
#include <uvm/uvm_ddb.h>
#include <uvm/uvm_pdpolicy.h>
/*
* 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 enable it from machdep code here.
*/
bool vm_page_zero_enable = false;
/*
* number of pages per-CPU to reserve for the kernel.
*/
#ifndef UVM_RESERVED_PAGES_PER_CPU
#define UVM_RESERVED_PAGES_PER_CPU 5
#endif
int vm_page_reserve_kernel = UVM_RESERVED_PAGES_PER_CPU;
/*
* physical memory size;
*/
psize_t physmem;
/*
* 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 allocate an initial number of page colors in uvm_page_init(),
* and remember them. We may re-color pages as cache sizes are
* discovered during the autoconfiguration phase. But we can never
* free the initial set of buckets, since they are allocated using
* uvm_pageboot_alloc().
*/
static size_t recolored_pages_memsize /* = 0 */;
#ifdef DEBUG
vaddr_t uvm_zerocheckkva;
#endif /* DEBUG */
/*
* These functions are reserved for uvm(9) internal use and are not
* exported in the header file uvm_physseg.h
*
* Thus they are redefined here.
*/
void uvm_physseg_init_seg(uvm_physseg_t, struct vm_page *);
void uvm_physseg_seg_chomp_slab(uvm_physseg_t, struct vm_page *, size_t);
/* returns a pgs array */
struct vm_page *uvm_physseg_seg_alloc_from_slab(uvm_physseg_t, size_t);
/*
* local prototypes
*/
static void uvm_pageinsert(struct uvm_object *, struct vm_page *);
static void uvm_pageremove(struct uvm_object *, struct vm_page *);
/*
* per-object tree of pages
*/
static signed int
uvm_page_compare_nodes(void *ctx, const void *n1, const void *n2)
{
const struct vm_page *pg1 = n1;
const struct vm_page *pg2 = n2;
const voff_t a = pg1->offset;
const voff_t b = pg2->offset;
if (a < b)
return -1;
if (a > b)
return 1;
return 0;
}
static signed int
uvm_page_compare_key(void *ctx, const void *n, const void *key)
{
const struct vm_page *pg = n;
const voff_t a = pg->offset;
const voff_t b = *(const voff_t *)key;
if (a < b)
return -1;
if (a > b)
return 1;
return 0;
}
const rb_tree_ops_t uvm_page_tree_ops = {
.rbto_compare_nodes = uvm_page_compare_nodes,
.rbto_compare_key = uvm_page_compare_key,
.rbto_node_offset = offsetof(struct vm_page, rb_node),
.rbto_context = NULL
};
/*
* inline functions
*/
/*
* uvm_pageinsert: insert a page in the object.
*
* => 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
*/
static inline void
uvm_pageinsert_list(struct uvm_object *uobj, struct vm_page *pg,
struct vm_page *where)
{
KASSERT(uobj == pg->uobject);
KASSERT(mutex_owned(uobj->vmobjlock));
KASSERT((pg->flags & PG_TABLED) == 0);
KASSERT(where == NULL || (where->flags & PG_TABLED));
KASSERT(where == NULL || (where->uobject == uobj));
if (UVM_OBJ_IS_VNODE(uobj)) {
if (uobj->uo_npages == 0) {
struct vnode *vp = (struct vnode *)uobj;
vholdl(vp);
}
if (UVM_OBJ_IS_VTEXT(uobj)) {
atomic_inc_uint(&uvmexp.execpages);
} else {
atomic_inc_uint(&uvmexp.filepages);
}
} else if (UVM_OBJ_IS_AOBJ(uobj)) {
atomic_inc_uint(&uvmexp.anonpages);
}
if (where)
TAILQ_INSERT_AFTER(&uobj->memq, where, pg, listq.queue);
else
TAILQ_INSERT_TAIL(&uobj->memq, pg, listq.queue);
pg->flags |= PG_TABLED;
uobj->uo_npages++;
}
static inline void
uvm_pageinsert_tree(struct uvm_object *uobj, struct vm_page *pg)
{
struct vm_page *ret __diagused;
KASSERT(uobj == pg->uobject);
ret = rb_tree_insert_node(&uobj->rb_tree, pg);
KASSERT(ret == pg);
}
static inline void
uvm_pageinsert(struct uvm_object *uobj, struct vm_page *pg)
{
KDASSERT(uobj != NULL);
uvm_pageinsert_tree(uobj, pg);
uvm_pageinsert_list(uobj, pg, NULL);
}
/*
* uvm_page_remove: remove page from object.
*
* => caller must lock object
* => caller must lock page queues
*/
static inline void
uvm_pageremove_list(struct uvm_object *uobj, struct vm_page *pg)
{
KASSERT(uobj == pg->uobject);
KASSERT(mutex_owned(uobj->vmobjlock));
KASSERT(pg->flags & PG_TABLED);
if (UVM_OBJ_IS_VNODE(uobj)) {
if (uobj->uo_npages == 1) {
struct vnode *vp = (struct vnode *)uobj;
holdrelel(vp);
}
if (UVM_OBJ_IS_VTEXT(uobj)) {
atomic_dec_uint(&uvmexp.execpages);
} else {
atomic_dec_uint(&uvmexp.filepages);
}
} else if (UVM_OBJ_IS_AOBJ(uobj)) {
atomic_dec_uint(&uvmexp.anonpages);
}
/* object should be locked */
uobj->uo_npages--;
TAILQ_REMOVE(&uobj->memq, pg, listq.queue);
pg->flags &= ~PG_TABLED;
pg->uobject = NULL;
}
static inline void
uvm_pageremove_tree(struct uvm_object *uobj, struct vm_page *pg)
{
KASSERT(uobj == pg->uobject);
rb_tree_remove_node(&uobj->rb_tree, pg);
}
static inline void
uvm_pageremove(struct uvm_object *uobj, struct vm_page *pg)
{
KDASSERT(uobj != NULL);
uvm_pageremove_tree(uobj, pg);
uvm_pageremove_list(uobj, pg);
}
static void
uvm_page_init_buckets(struct pgfreelist *pgfl)
{
int color, i;
for (color = 0; color < uvmexp.ncolors; color++) {
for (i = 0; i < PGFL_NQUEUES; i++) {
LIST_INIT(&pgfl->pgfl_buckets[color].pgfl_queues[i]);
}
}
}
/*
* 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(vaddr_t *kvm_startp, vaddr_t *kvm_endp)
{
static struct uvm_cpu boot_cpu;
psize_t freepages, pagecount, bucketcount, n;
struct pgflbucket *bucketarray, *cpuarray;
struct vm_page *pagearray;
uvm_physseg_t bank;
int lcv;
KASSERT(ncpu <= 1);
CTASSERT(sizeof(pagearray->offset) >= sizeof(struct uvm_cpu *));
/*
* init the page queues and page queue locks, except the free
* list; we allocate that later (with the initial vm_page
* structures).
*/
uvm.cpus[0] = &boot_cpu;
curcpu()->ci_data.cpu_uvm = &boot_cpu;
uvmpdpol_init();
mutex_init(&uvm_pageqlock, MUTEX_DRIVER, IPL_NONE);
mutex_init(&uvm_fpageqlock, MUTEX_DRIVER, IPL_VM);
/*
* 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 (uvm_physseg_get_last() == UVM_PHYSSEG_TYPE_INVALID)
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 (bank = uvm_physseg_get_first();
uvm_physseg_valid_p(bank) ;
bank = uvm_physseg_get_next(bank)) {
freepages += (uvm_physseg_get_end(bank) - uvm_physseg_get_start(bank));
}
/*
* Let MD code initialize the number of colors, or default
* to 1 color if MD code doesn't care.
*/
if (uvmexp.ncolors == 0)
uvmexp.ncolors = 1;
uvmexp.colormask = uvmexp.ncolors - 1;
KASSERT((uvmexp.colormask & uvmexp.ncolors) == 0);
/*
* 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).
*/
bucketcount = uvmexp.ncolors * VM_NFREELIST;
pagecount = ((freepages + 1) << PAGE_SHIFT) /
(PAGE_SIZE + sizeof(struct vm_page));
bucketarray = (void *)uvm_pageboot_alloc((bucketcount *
sizeof(struct pgflbucket) * 2) + (pagecount *
sizeof(struct vm_page)));
cpuarray = bucketarray + bucketcount;
pagearray = (struct vm_page *)(bucketarray + bucketcount * 2);
for (lcv = 0; lcv < VM_NFREELIST; lcv++) {
uvm.page_free[lcv].pgfl_buckets =
(bucketarray + (lcv * uvmexp.ncolors));
uvm_page_init_buckets(&uvm.page_free[lcv]);
uvm.cpus[0]->page_free[lcv].pgfl_buckets =
(cpuarray + (lcv * uvmexp.ncolors));
uvm_page_init_buckets(&uvm.cpus[0]->page_free[lcv]);
}
memset(pagearray, 0, pagecount * sizeof(struct vm_page));
/*
* init the vm_page structures and put them in the correct place.
*/
/* First init the extent */
for (bank = uvm_physseg_get_first(),
uvm_physseg_seg_chomp_slab(bank, pagearray, pagecount);
uvm_physseg_valid_p(bank);
bank = uvm_physseg_get_next(bank)) {
n = uvm_physseg_get_end(bank) - uvm_physseg_get_start(bank);
uvm_physseg_seg_alloc_from_slab(bank, n);
uvm_physseg_init_seg(bank, pagearray);
/* set up page array pointers */
pagearray += n;
pagecount -= n;
}
/*
* 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);
#ifdef DEBUG
/*
* steal kva for uvm_pagezerocheck().
*/
uvm_zerocheckkva = *kvm_startp;
*kvm_startp += PAGE_SIZE;
#endif /* DEBUG */
/*
* init various thresholds.
*/
uvmexp.reserve_pagedaemon = 1;
uvmexp.reserve_kernel = vm_page_reserve_kernel;
/*
* determine if we should zero pages in the idle loop.
*/
uvm.cpus[0]->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(void)
{
/*
* If uvmexp.pagesize is 0 at this point, we expect PAGE_SIZE
* to be a constant (indicated by being a non-zero value).
*/
if (uvmexp.pagesize == 0) {
if (PAGE_SIZE == 0)
panic("uvm_setpagesize: uvmexp.pagesize not set");
uvmexp.pagesize = PAGE_SIZE;
}
uvmexp.pagemask = uvmexp.pagesize - 1;
if ((uvmexp.pagemask & uvmexp.pagesize) != 0)
panic("uvm_setpagesize: page size %u (%#x) not a power of two",
uvmexp.pagesize, uvmexp.pagesize);
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(vsize_t size)
{
static bool initialized = false;
vaddr_t addr;
#if !defined(PMAP_STEAL_MEMORY)
vaddr_t vaddr;
paddr_t paddr;
#endif
/*
* 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;
}
/* round to page size */
size = round_page(size);
uvmexp.bootpages += atop(size);
#if defined(PMAP_STEAL_MEMORY)
/*
* defer bootstrap allocation to MD code (it may want to allocate
* from a direct-mapped segment). pmap_steal_memory should adjust
* virtual_space_start/virtual_space_end if necessary.
*/
addr = pmap_steal_memory(size, &virtual_space_start,
&virtual_space_end);
return(addr);
#else /* !PMAP_STEAL_MEMORY */
/*
* 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");
/*
* Note this memory is no longer managed, so using
* pmap_kenter is safe.
*/
pmap_kenter_pa(vaddr, paddr, VM_PROT_READ|VM_PROT_WRITE, 0);
}
pmap_update(pmap_kernel());
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.
*/
/* subroutine: try to allocate from memory chunks on the specified freelist */
static bool uvm_page_physget_freelist(paddr_t *, int);
static bool
uvm_page_physget_freelist(paddr_t *paddrp, int freelist)
{
uvm_physseg_t lcv;
/* pass 1: try allocating from a matching end */
#if (VM_PHYSSEG_STRAT == VM_PSTRAT_BIGFIRST)
for (lcv = uvm_physseg_get_last(); uvm_physseg_valid_p(lcv); lcv = uvm_physseg_get_prev(lcv))
#else
for (lcv = uvm_physseg_get_first(); uvm_physseg_valid_p(lcv); lcv = uvm_physseg_get_next(lcv))
#endif
{
if (uvm.page_init_done == true)
panic("uvm_page_physget: called _after_ bootstrap");
/* Try to match at front or back on unused segment */
if (uvm_page_physunload(lcv, freelist, paddrp))
return true;
}
/* pass2: forget about matching ends, just allocate something */
#if (VM_PHYSSEG_STRAT == VM_PSTRAT_BIGFIRST)
for (lcv = uvm_physseg_get_last(); uvm_physseg_valid_p(lcv); lcv = uvm_physseg_get_prev(lcv))
#else
for (lcv = uvm_physseg_get_first(); uvm_physseg_valid_p(lcv); lcv = uvm_physseg_get_next(lcv))
#endif
{
/* Try the front regardless. */
if (uvm_page_physunload_force(lcv, freelist, paddrp))
return true;
}
return false;
}
bool
uvm_page_physget(paddr_t *paddrp)
{
int i;
/* try in the order of freelist preference */
for (i = 0; i < VM_NFREELIST; i++)
if (uvm_page_physget_freelist(paddrp, i) == true)
return (true);
return (false);
}
#endif /* PMAP_STEAL_MEMORY */
/*
* PHYS_TO_VM_PAGE: find vm_page for a PA. used by MI code to get vm_pages
* back from an I/O mapping (ugh!). used in some MD code as well.
*/
struct vm_page *
uvm_phys_to_vm_page(paddr_t pa)
{
paddr_t pf = atop(pa);
paddr_t off;
uvm_physseg_t upm;
upm = uvm_physseg_find(pf, &off);
if (upm != UVM_PHYSSEG_TYPE_INVALID)
return uvm_physseg_get_pg(upm, off);
return(NULL);
}
paddr_t
uvm_vm_page_to_phys(const struct vm_page *pg)
{
return pg->phys_addr;
}
/*
* uvm_page_recolor: Recolor the pages if the new bucket count is
* larger than the old one.
*/
void
uvm_page_recolor(int newncolors)
{
struct pgflbucket *bucketarray, *cpuarray, *oldbucketarray;
struct pgfreelist gpgfl, pgfl;
struct vm_page *pg;
vsize_t bucketcount;
size_t bucketmemsize, oldbucketmemsize;
int color, i, ocolors;
int lcv;
struct uvm_cpu *ucpu;
KASSERT(((newncolors - 1) & newncolors) == 0);
if (newncolors <= uvmexp.ncolors)
return;
if (uvm.page_init_done == false) {
uvmexp.ncolors = newncolors;
return;
}
bucketcount = newncolors * VM_NFREELIST;
bucketmemsize = bucketcount * sizeof(struct pgflbucket) * 2;
bucketarray = kmem_alloc(bucketmemsize, KM_SLEEP);
cpuarray = bucketarray + bucketcount;
mutex_spin_enter(&uvm_fpageqlock);
/* Make sure we should still do this. */
if (newncolors <= uvmexp.ncolors) {
mutex_spin_exit(&uvm_fpageqlock);
kmem_free(bucketarray, bucketmemsize);
return;
}
oldbucketarray = uvm.page_free[0].pgfl_buckets;
ocolors = uvmexp.ncolors;
uvmexp.ncolors = newncolors;
uvmexp.colormask = uvmexp.ncolors - 1;
ucpu = curcpu()->ci_data.cpu_uvm;
for (lcv = 0; lcv < VM_NFREELIST; lcv++) {
gpgfl.pgfl_buckets = (bucketarray + (lcv * newncolors));
pgfl.pgfl_buckets = (cpuarray + (lcv * uvmexp.ncolors));
uvm_page_init_buckets(&gpgfl);
uvm_page_init_buckets(&pgfl);
for (color = 0; color < ocolors; color++) {
for (i = 0; i < PGFL_NQUEUES; i++) {
while ((pg = LIST_FIRST(&uvm.page_free[
lcv].pgfl_buckets[color].pgfl_queues[i]))
!= NULL) {
LIST_REMOVE(pg, pageq.list); /* global */
LIST_REMOVE(pg, listq.list); /* cpu */
LIST_INSERT_HEAD(&gpgfl.pgfl_buckets[
VM_PGCOLOR_BUCKET(pg)].pgfl_queues[
i], pg, pageq.list);
LIST_INSERT_HEAD(&pgfl.pgfl_buckets[
VM_PGCOLOR_BUCKET(pg)].pgfl_queues[
i], pg, listq.list);
}
}
}
uvm.page_free[lcv].pgfl_buckets = gpgfl.pgfl_buckets;
ucpu->page_free[lcv].pgfl_buckets = pgfl.pgfl_buckets;
}
oldbucketmemsize = recolored_pages_memsize;
recolored_pages_memsize = bucketmemsize;
mutex_spin_exit(&uvm_fpageqlock);
if (oldbucketmemsize) {
kmem_free(oldbucketarray, oldbucketmemsize);
}
/*
* this calls uvm_km_alloc() which may want to hold
* uvm_fpageqlock.
*/
uvm_pager_realloc_emerg();
}
/*
* uvm_cpu_attach: initialize per-CPU data structures.
*/
void
uvm_cpu_attach(struct cpu_info *ci)
{
struct pgflbucket *bucketarray;
struct pgfreelist pgfl;
struct uvm_cpu *ucpu;
vsize_t bucketcount;
int lcv;
if (CPU_IS_PRIMARY(ci)) {
/* Already done in uvm_page_init(). */
goto attachrnd;
}
/* Add more reserve pages for this CPU. */
uvmexp.reserve_kernel += vm_page_reserve_kernel;
/* Configure this CPU's free lists. */
bucketcount = uvmexp.ncolors * VM_NFREELIST;
bucketarray = kmem_alloc(bucketcount * sizeof(struct pgflbucket),
KM_SLEEP);
ucpu = kmem_zalloc(sizeof(*ucpu), KM_SLEEP);
uvm.cpus[cpu_index(ci)] = ucpu;
ci->ci_data.cpu_uvm = ucpu;
for (lcv = 0; lcv < VM_NFREELIST; lcv++) {
pgfl.pgfl_buckets = (bucketarray + (lcv * uvmexp.ncolors));
uvm_page_init_buckets(&pgfl);
ucpu->page_free[lcv].pgfl_buckets = pgfl.pgfl_buckets;
}
attachrnd:
/*
* Attach RNG source for this CPU's VM events
*/
rnd_attach_source(&uvm.cpus[cpu_index(ci)]->rs,
ci->ci_data.cpu_name, RND_TYPE_VM,
RND_FLAG_COLLECT_TIME|RND_FLAG_COLLECT_VALUE|
RND_FLAG_ESTIMATE_VALUE);
}
/*
* uvm_pagealloc_pgfl: helper routine for uvm_pagealloc_strat
*/
static struct vm_page *
uvm_pagealloc_pgfl(struct uvm_cpu *ucpu, int flist, int try1, int try2,
int *trycolorp)
{
struct pgflist *freeq;
struct vm_page *pg;
int color, trycolor = *trycolorp;
struct pgfreelist *gpgfl, *pgfl;
KASSERT(mutex_owned(&uvm_fpageqlock));
color = trycolor;
pgfl = &ucpu->page_free[flist];
gpgfl = &uvm.page_free[flist];
do {
/* cpu, try1 */
if ((pg = LIST_FIRST((freeq =
&pgfl->pgfl_buckets[color].pgfl_queues[try1]))) != NULL) {
KASSERT(pg->pqflags & PQ_FREE);
KASSERT(try1 == PGFL_ZEROS || !(pg->flags & PG_ZERO));
KASSERT(try1 == PGFL_UNKNOWN || (pg->flags & PG_ZERO));
KASSERT(ucpu == VM_FREE_PAGE_TO_CPU(pg));
VM_FREE_PAGE_TO_CPU(pg)->pages[try1]--;
uvmexp.cpuhit++;
goto gotit;
}
/* global, try1 */
if ((pg = LIST_FIRST((freeq =
&gpgfl->pgfl_buckets[color].pgfl_queues[try1]))) != NULL) {
KASSERT(pg->pqflags & PQ_FREE);
KASSERT(try1 == PGFL_ZEROS || !(pg->flags & PG_ZERO));
KASSERT(try1 == PGFL_UNKNOWN || (pg->flags & PG_ZERO));
KASSERT(ucpu != VM_FREE_PAGE_TO_CPU(pg));
VM_FREE_PAGE_TO_CPU(pg)->pages[try1]--;
uvmexp.cpumiss++;
goto gotit;
}
/* cpu, try2 */
if ((pg = LIST_FIRST((freeq =
&pgfl->pgfl_buckets[color].pgfl_queues[try2]))) != NULL) {
KASSERT(pg->pqflags & PQ_FREE);
KASSERT(try2 == PGFL_ZEROS || !(pg->flags & PG_ZERO));
KASSERT(try2 == PGFL_UNKNOWN || (pg->flags & PG_ZERO));
KASSERT(ucpu == VM_FREE_PAGE_TO_CPU(pg));
VM_FREE_PAGE_TO_CPU(pg)->pages[try2]--;
uvmexp.cpuhit++;
goto gotit;
}
/* global, try2 */
if ((pg = LIST_FIRST((freeq =
&gpgfl->pgfl_buckets[color].pgfl_queues[try2]))) != NULL) {
KASSERT(pg->pqflags & PQ_FREE);
KASSERT(try2 == PGFL_ZEROS || !(pg->flags & PG_ZERO));
KASSERT(try2 == PGFL_UNKNOWN || (pg->flags & PG_ZERO));
KASSERT(ucpu != VM_FREE_PAGE_TO_CPU(pg));
VM_FREE_PAGE_TO_CPU(pg)->pages[try2]--;
uvmexp.cpumiss++;
goto gotit;
}
color = (color + 1) & uvmexp.colormask;
} while (color != trycolor);
return (NULL);
gotit:
LIST_REMOVE(pg, pageq.list); /* global list */
LIST_REMOVE(pg, listq.list); /* per-cpu list */
uvmexp.free--;
/* update zero'd page count */
if (pg->flags & PG_ZERO)
uvmexp.zeropages--;
if (color == trycolor)
uvmexp.colorhit++;
else {
uvmexp.colormiss++;
*trycolorp = color;
}
return (pg);
}
/*
* 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 obj's tree)
* => 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.
* => policy decision: it is more important to pull a page off of the
* appropriate priority free list than it is to get a zero'd or
* unknown contents page. This is because we live with the
* consequences of a bad free list decision for the entire
* lifetime of the page, e.g. if the page comes from memory that
* is slower to access.
*/
struct vm_page *
uvm_pagealloc_strat(struct uvm_object *obj, voff_t off, struct vm_anon *anon,
int flags, int strat, int free_list)
{
int try1, try2, zeroit = 0, color;
int lcv;
struct uvm_cpu *ucpu;
struct vm_page *pg;
lwp_t *l;
KASSERT(obj == NULL || anon == NULL);
KASSERT(anon == NULL || (flags & UVM_FLAG_COLORMATCH) || off == 0);
KASSERT(off == trunc_page(off));
KASSERT(obj == NULL || mutex_owned(obj->vmobjlock));
KASSERT(anon == NULL || anon->an_lock == NULL ||
mutex_owned(anon->an_lock));
mutex_spin_enter(&uvm_fpageqlock);
/*
* This implements a global round-robin page coloring
* algorithm.
*/
ucpu = curcpu()->ci_data.cpu_uvm;
if (flags & UVM_FLAG_COLORMATCH) {
color = atop(off) & uvmexp.colormask;
} else {
color = ucpu->page_free_nextcolor;
}
/*
* check to see if we need to generate some free pages waking
* the pagedaemon.
*/
uvm_kick_pdaemon();
/*
* fail if any of these conditions is true:
* [1] there really are no free pages, or
* [2] only kernel "reserved" pages remain and
* reserved pages have not been requested.
* [3] only pagedaemon "reserved" pages remain and
* the requestor isn't the pagedaemon.
* we make kernel reserve pages available if called by a
* kernel thread or a realtime thread.
*/
l = curlwp;
if (__predict_true(l != NULL) && lwp_eprio(l) >= PRI_KTHREAD) {
flags |= UVM_PGA_USERESERVE;
}
if ((uvmexp.free <= uvmexp.reserve_kernel &&
(flags & UVM_PGA_USERESERVE) == 0) ||
(uvmexp.free <= uvmexp.reserve_pagedaemon &&
curlwp != uvm.pagedaemon_lwp))
goto fail;
#if PGFL_NQUEUES != 2
#error uvm_pagealloc_strat needs to be updated
#endif
/*
* If we want a zero'd page, try the ZEROS queue first, otherwise
* we try the UNKNOWN queue first.
*/
if (flags & UVM_PGA_ZERO) {
try1 = PGFL_ZEROS;
try2 = PGFL_UNKNOWN;
} else {
try1 = PGFL_UNKNOWN;
try2 = PGFL_ZEROS;
}
again: