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NetBSD/sys/uvm/uvm_pglist.c

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/* $NetBSD: uvm_pglist.c,v 1.61 2011/04/23 18:14:13 rmind Exp $ */
/*-
* Copyright (c) 1997 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
* NASA Ames Research Center.
*
* 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
*/
/*
* uvm_pglist.c: pglist functions
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: uvm_pglist.c,v 1.61 2011/04/23 18:14:13 rmind Exp $");
#include <sys/param.h>
#include <sys/systm.h>
#include <uvm/uvm.h>
#include <uvm/uvm_pdpolicy.h>
#ifdef VM_PAGE_ALLOC_MEMORY_STATS
#define STAT_INCR(v) (v)++
#define STAT_DECR(v) do { \
if ((v) == 0) \
printf("%s:%d -- Already 0!\n", __FILE__, __LINE__); \
else \
(v)--; \
} while (/*CONSTCOND*/ 0)
u_long uvm_pglistalloc_npages;
#else
#define STAT_INCR(v)
#define STAT_DECR(v)
#endif
/*
* uvm_pglistalloc: allocate a list of pages
*
* => allocated pages are placed onto an rlist. rlist is
* initialized by uvm_pglistalloc.
* => returns 0 on success or errno on failure
* => implementation allocates a single segment if any constraints are
* imposed by call arguments.
* => doesn't take into account clean non-busy pages on inactive list
* that could be used(?)
* => params:
* size the size of the allocation, rounded to page size.
* low the low address of the allowed allocation range.
* high the high address of the allowed allocation range.
* alignment memory must be aligned to this power-of-two boundary.
* boundary no segment in the allocation may cross this
* power-of-two boundary (relative to zero).
*/
static void
uvm_pglist_add(struct vm_page *pg, struct pglist *rlist)
{
int free_list, color, pgflidx;
KASSERT(mutex_owned(&uvm_fpageqlock));
#if PGFL_NQUEUES != 2
#error uvm_pglistalloc needs to be updated
#endif
free_list = uvm_page_lookup_freelist(pg);
color = VM_PGCOLOR_BUCKET(pg);
pgflidx = (pg->flags & PG_ZERO) ? PGFL_ZEROS : PGFL_UNKNOWN;
#ifdef NOT_DEBUG
struct vm_page *tp;
LIST_FOREACH(tp,
&uvm.page_free[free_list].pgfl_buckets[color].pgfl_queues[pgflidx],
pageq.list) {
if (tp == pg)
break;
}
if (tp == NULL)
panic("uvm_pglistalloc: page not on freelist");
#endif
LIST_REMOVE(pg, pageq.list); /* global */
LIST_REMOVE(pg, listq.list); /* cpu */
uvmexp.free--;
if (pg->flags & PG_ZERO)
uvmexp.zeropages--;
VM_FREE_PAGE_TO_CPU(pg)->pages[pgflidx]--;
pg->flags = PG_CLEAN;
pg->pqflags = 0;
pg->uobject = NULL;
pg->uanon = NULL;
TAILQ_INSERT_TAIL(rlist, pg, pageq.queue);
STAT_INCR(uvm_pglistalloc_npages);
}
static int
uvm_pglistalloc_c_ps(struct vm_physseg *ps, int num, paddr_t low, paddr_t high,
paddr_t alignment, paddr_t boundary, struct pglist *rlist)
{
signed int try, limit, tryidx, end, idx, skip;
struct vm_page *pgs;
int pagemask;
bool second_pass;
#ifdef DEBUG
paddr_t idxpa, lastidxpa;
int cidx = 0; /* XXX: GCC */
#endif
#ifdef PGALLOC_VERBOSE
printf("pgalloc: contig %d pgs from psi %zd\n", num, ps - vm_physmem);
#endif
KASSERT(mutex_owned(&uvm_fpageqlock));
low = atop(low);
high = atop(high);
alignment = atop(alignment);
/*
* Make sure that physseg falls within with range to be allocated from.
*/
if (high <= ps->avail_start || low >= ps->avail_end)
return 0;
/*
* We start our search at the just after where the last allocation
* succeeded.
*/
try = roundup2(max(low, ps->avail_start + ps->start_hint), alignment);
limit = min(high, ps->avail_end);
pagemask = ~((boundary >> PAGE_SHIFT) - 1);
skip = 0;
second_pass = false;
pgs = ps->pgs;
for (;;) {
bool ok = true;
signed int cnt;
if (try + num > limit) {
if (ps->start_hint == 0 || second_pass) {
/*
* We've run past the allowable range.
*/
return 0; /* FAIL = 0 pages*/
}
/*
* We've wrapped around the end of this segment
* so restart at the beginning but now our limit
* is were we started.
*/
second_pass = true;
try = roundup2(max(low, ps->avail_start), alignment);
limit = min(limit, ps->avail_start + ps->start_hint);
skip = 0;
continue;
}
if (boundary != 0 &&
((try ^ (try + num - 1)) & pagemask) != 0) {
/*
* Region crosses boundary. Jump to the boundary
* just crossed and ensure alignment.
*/
try = (try + num - 1) & pagemask;
try = roundup2(try, alignment);
skip = 0;
continue;
}
#ifdef DEBUG
/*
* Make sure this is a managed physical page.
*/
if (vm_physseg_find(try, &cidx) != ps - vm_physmem)
panic("pgalloc contig: botch1");
if (cidx != try - ps->start)
panic("pgalloc contig: botch2");
if (vm_physseg_find(try + num - 1, &cidx) != ps - vm_physmem)
panic("pgalloc contig: botch3");
if (cidx != try - ps->start + num - 1)
panic("pgalloc contig: botch4");
#endif
tryidx = try - ps->start;
end = tryidx + num;
/*
* Found a suitable starting page. See if the range is free.
*/
#ifdef PGALLOC_VERBOSE
printf("%s: ps=%p try=%#x end=%#x skip=%#x, align=%#"PRIxPADDR,
__func__, ps, tryidx, end, skip, alignment);
#endif
/*
* We start at the end and work backwards since if we find a
* non-free page, it makes no sense to continue.
*
* But on the plus size we have "vetted" some number of free
* pages. If this iteration fails, we may be able to skip
* testing most of those pages again in the next pass.
*/
for (idx = end - 1; idx >= tryidx + skip; idx--) {
if (VM_PAGE_IS_FREE(&pgs[idx]) == 0) {
ok = false;
break;
}
#ifdef DEBUG
if (idx > tryidx) {
idxpa = VM_PAGE_TO_PHYS(&pgs[idx]);
lastidxpa = VM_PAGE_TO_PHYS(&pgs[idx - 1]);
if ((lastidxpa + PAGE_SIZE) != idxpa) {
/*
* Region not contiguous.
*/
panic("pgalloc contig: botch5");
}
if (boundary != 0 &&
((lastidxpa ^ idxpa) & ~(boundary - 1))
!= 0) {
/*
* Region crosses boundary.
*/
panic("pgalloc contig: botch6");
}
}
#endif
}
if (ok) {
while (skip-- > 0) {
KDASSERT(VM_PAGE_IS_FREE(&pgs[tryidx + skip]));
}
#ifdef PGALLOC_VERBOSE
printf(": ok\n");
#endif
break;
}
#ifdef PGALLOC_VERBOSE
printf(": non-free at %#x\n", idx - tryidx);
#endif
/*
* count the number of pages we can advance
* since we know they aren't all free.
*/
cnt = idx + 1 - tryidx;
/*
* now round up that to the needed alignment.
*/
cnt = roundup2(cnt, alignment);
/*
* The number of pages we can skip checking
* (might be 0 if cnt > num).
*/
skip = max(num - cnt, 0);
try += cnt;
}
/*
* we have a chunk of memory that conforms to the requested constraints.
*/
for (idx = tryidx, pgs += idx; idx < end; idx++, pgs++)
uvm_pglist_add(pgs, rlist);
/*
* the next time we need to search this segment, start after this
* chunk of pages we just allocated.
*/
ps->start_hint = try + num - ps->avail_start;
KASSERTMSG(ps->start_hint <= ps->avail_end - ps->avail_start,
("%x %u (%#x) <= %#"PRIxPADDR" - %#"PRIxPADDR" (%#"PRIxPADDR")",
try + num,
ps->start_hint, ps->start_hint, ps->avail_end, ps->avail_start,
ps->avail_end - ps->avail_start));
#ifdef PGALLOC_VERBOSE
printf("got %d pgs\n", num);
#endif
return num; /* number of pages allocated */
}
static int
uvm_pglistalloc_contig(int num, paddr_t low, paddr_t high, paddr_t alignment,
paddr_t boundary, struct pglist *rlist)
{
int fl, psi;
struct vm_physseg *ps;
int error;
/* Default to "lose". */
error = ENOMEM;
/*
* Block all memory allocation and lock the free list.
*/
mutex_spin_enter(&uvm_fpageqlock);
/* Are there even any free pages? */
if (uvmexp.free <= (uvmexp.reserve_pagedaemon + uvmexp.reserve_kernel))
goto out;
for (fl = 0; fl < VM_NFREELIST; fl++) {
#if (VM_PHYSSEG_STRAT == VM_PSTRAT_BIGFIRST)
for (psi = vm_nphysseg - 1 ; psi >= 0 ; psi--)
#else
for (psi = 0 ; psi < vm_nphysseg ; psi++)
#endif
{
ps = &vm_physmem[psi];
if (ps->free_list != fl)
continue;
num -= uvm_pglistalloc_c_ps(ps, num, low, high,
alignment, boundary, rlist);
if (num == 0) {
#ifdef PGALLOC_VERBOSE
printf("pgalloc: %"PRIxMAX"-%"PRIxMAX"\n",
(uintmax_t) VM_PAGE_TO_PHYS(TAILQ_FIRST(rlist)),
(uintmax_t) VM_PAGE_TO_PHYS(TAILQ_LAST(rlist, pglist)));
#endif
error = 0;
goto out;
}
}
}
out:
/*
* check to see if we need to generate some free pages waking
* the pagedaemon.
*/
uvm_kick_pdaemon();
mutex_spin_exit(&uvm_fpageqlock);
return (error);
}
static int
uvm_pglistalloc_s_ps(struct vm_physseg *ps, int num, paddr_t low, paddr_t high,
struct pglist *rlist)
{
int todo, limit, try;
struct vm_page *pg;
bool second_pass;
#ifdef PGALLOC_VERBOSE
printf("pgalloc: simple %d pgs from psi %zd\n", num, ps - vm_physmem);
#endif
KASSERT(mutex_owned(&uvm_fpageqlock));
KASSERT(ps->start <= ps->avail_start);
KASSERT(ps->start <= ps->avail_end);
KASSERT(ps->avail_start <= ps->end);
KASSERT(ps->avail_end <= ps->end);
low = atop(low);
high = atop(high);
todo = num;
try = max(low, ps->avail_start + ps->start_hint);
limit = min(high, ps->avail_end);
pg = &ps->pgs[try - ps->start];
second_pass = false;
/*
* Make sure that physseg falls within with range to be allocated from.
*/
if (high <= ps->avail_start || low >= ps->avail_end)
return 0;
again:
for (;; try++, pg++) {
if (try >= limit) {
if (ps->start_hint == 0 || second_pass) {
try = limit - 1;
break;
}
second_pass = true;
try = max(low, ps->avail_start);
limit = min(limit, ps->avail_start + ps->start_hint);
pg = &ps->pgs[try - ps->start];
goto again;
}
#if defined(DEBUG)
{
int cidx = 0;
const int bank = vm_physseg_find(try, &cidx);
KDASSERTMSG(bank == ps - vm_physmem,
("vm_physseg_find(%#x) (%d) != ps %zd",
try, bank, ps - vm_physmem));
KDASSERTMSG(cidx == try - ps->start,
("vm_physseg_find(%#x): %#x != off %"PRIxPADDR,
try, cidx, try - ps->start));
}
#endif
if (VM_PAGE_IS_FREE(pg) == 0)
continue;
uvm_pglist_add(pg, rlist);
if (--todo == 0) {
break;
}
}
/*
* The next time we need to search this segment,
* start just after the pages we just allocated.
*/
ps->start_hint = try + 1 - ps->avail_start;
KASSERTMSG(ps->start_hint <= ps->avail_end - ps->avail_start,
("%#x %u (%#x) <= %#"PRIxPADDR" - %#"PRIxPADDR" (%#"PRIxPADDR")",
try + 1,
ps->start_hint, ps->start_hint, ps->avail_end, ps->avail_start,
ps->avail_end - ps->avail_start));
#ifdef PGALLOC_VERBOSE
printf("got %d pgs\n", num - todo);
#endif
return (num - todo); /* number of pages allocated */
}
static int
uvm_pglistalloc_simple(int num, paddr_t low, paddr_t high,
struct pglist *rlist, int waitok)
{
int fl, psi, error;
struct vm_physseg *ps;
/* Default to "lose". */
error = ENOMEM;
again:
/*
* Block all memory allocation and lock the free list.
*/
mutex_spin_enter(&uvm_fpageqlock);
/* Are there even any free pages? */
if (uvmexp.free <= (uvmexp.reserve_pagedaemon + uvmexp.reserve_kernel))
goto out;
for (fl = 0; fl < VM_NFREELIST; fl++) {
#if (VM_PHYSSEG_STRAT == VM_PSTRAT_BIGFIRST)
for (psi = vm_nphysseg - 1 ; psi >= 0 ; psi--)
#else
for (psi = 0 ; psi < vm_nphysseg ; psi++)
#endif
{
ps = &vm_physmem[psi];
if (ps->free_list != fl)
continue;
num -= uvm_pglistalloc_s_ps(ps, num, low, high, rlist);
if (num == 0) {
error = 0;
goto out;
}
}
}
out:
/*
* check to see if we need to generate some free pages waking
* the pagedaemon.
*/
uvm_kick_pdaemon();
mutex_spin_exit(&uvm_fpageqlock);
if (error) {
if (waitok) {
/* XXX perhaps some time limitation? */
#ifdef DEBUG
printf("pglistalloc waiting\n");
#endif
uvm_wait("pglalloc");
goto again;
} else
uvm_pglistfree(rlist);
}
#ifdef PGALLOC_VERBOSE
if (!error)
printf("pgalloc: %"PRIxMAX"..%"PRIxMAX"\n",
(uintmax_t) VM_PAGE_TO_PHYS(TAILQ_FIRST(rlist)),
(uintmax_t) VM_PAGE_TO_PHYS(TAILQ_LAST(rlist, pglist)));
#endif
return (error);
}
int
uvm_pglistalloc(psize_t size, paddr_t low, paddr_t high, paddr_t alignment,
paddr_t boundary, struct pglist *rlist, int nsegs, int waitok)
{
int num, res;
KASSERT((alignment & (alignment - 1)) == 0);
KASSERT((boundary & (boundary - 1)) == 0);
/*
* Our allocations are always page granularity, so our alignment
* must be, too.
*/
if (alignment < PAGE_SIZE)
alignment = PAGE_SIZE;
if (boundary != 0 && boundary < size)
return (EINVAL);
num = atop(round_page(size));
low = roundup2(low, alignment);
TAILQ_INIT(rlist);
if ((nsegs < size >> PAGE_SHIFT) || (alignment != PAGE_SIZE) ||
(boundary != 0))
res = uvm_pglistalloc_contig(num, low, high, alignment,
boundary, rlist);
else
res = uvm_pglistalloc_simple(num, low, high, rlist, waitok);
return (res);
}
/*
* uvm_pglistfree: free a list of pages
*
* => pages should already be unmapped
*/
void
uvm_pglistfree(struct pglist *list)
{
struct uvm_cpu *ucpu;
struct vm_page *pg;
int index, color, queue;
bool iszero;
/*
* Lock the free list and free each page.
*/
mutex_spin_enter(&uvm_fpageqlock);
ucpu = curcpu()->ci_data.cpu_uvm;
while ((pg = TAILQ_FIRST(list)) != NULL) {
KASSERT(!uvmpdpol_pageisqueued_p(pg));
TAILQ_REMOVE(list, pg, pageq.queue);
iszero = (pg->flags & PG_ZERO);
pg->pqflags = PQ_FREE;
#ifdef DEBUG
pg->uobject = (void *)0xdeadbeef;
pg->uanon = (void *)0xdeadbeef;
#endif /* DEBUG */
#ifdef DEBUG
if (iszero)
uvm_pagezerocheck(pg);
#endif /* DEBUG */
index = uvm_page_lookup_freelist(pg);
color = VM_PGCOLOR_BUCKET(pg);
queue = iszero ? PGFL_ZEROS : PGFL_UNKNOWN;
pg->offset = (uintptr_t)ucpu;
LIST_INSERT_HEAD(&uvm.page_free[index].pgfl_buckets[color].
pgfl_queues[queue], pg, pageq.list);
LIST_INSERT_HEAD(&ucpu->page_free[index].pgfl_buckets[color].
pgfl_queues[queue], pg, listq.list);
uvmexp.free++;
if (iszero)
uvmexp.zeropages++;
ucpu->pages[queue]++;
STAT_DECR(uvm_pglistalloc_npages);
}
if (ucpu->pages[PGFL_ZEROS] < ucpu->pages[PGFL_UNKNOWN])
ucpu->page_idle_zero = vm_page_zero_enable;
mutex_spin_exit(&uvm_fpageqlock);
}
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