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/* $OpenBSD: uvm_object.c,v 1.25 2022/02/21 16:08:36 kn Exp $ */
/*
* Copyright (c) 2006, 2010, 2019 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Mindaugas Rasiukevicius.
*
* 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_object.c: operate with memory objects
*
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/mman.h>
#include <sys/atomic.h>
#include <sys/rwlock.h>
#include <uvm/uvm.h>
/* Dummy object used by some pmaps for sanity checks. */
const struct uvm_pagerops pmap_pager = {
/* nothing */
};
/* Dummy object used by the buffer cache for sanity checks. */
const struct uvm_pagerops bufcache_pager = {
/* nothing */
};
/* Page count to fetch per single step. */
#define FETCH_PAGECOUNT 16
/*
* uvm_obj_init: initialize UVM memory object.
*/
void
uvm_obj_init(struct uvm_object *uobj, const struct uvm_pagerops *pgops, int refs)
{
int alock;
alock = ((pgops != NULL) && (pgops != &pmap_pager) &&
(pgops != &bufcache_pager) && (refs != UVM_OBJ_KERN));
if (alock) {
/* Allocate and assign a lock. */
rw_obj_alloc(&uobj->vmobjlock, "uobjlk");
} else {
/* The lock will need to be set via uvm_obj_setlock(). */
uobj->vmobjlock = NULL;
}
uobj->pgops = pgops;
RBT_INIT(uvm_objtree, &uobj->memt);
uobj->uo_npages = 0;
uobj->uo_refs = refs;
}
/*
* uvm_obj_destroy: destroy UVM memory object.
*/
void
uvm_obj_destroy(struct uvm_object *uo)
{
KASSERT(RBT_EMPTY(uvm_objtree, &uo->memt));
rw_obj_free(uo->vmobjlock);
}
/*
* uvm_obj_setlock: assign a vmobjlock to the UVM object.
*
* => Caller is responsible to ensure that UVM objects is not use.
* => Only dynamic lock may be previously set. We drop the reference then.
*/
void
uvm_obj_setlock(struct uvm_object *uo, struct rwlock *lockptr)
{
struct rwlock *olockptr = uo->vmobjlock;
if (olockptr) {
/* Drop the reference on the old lock. */
rw_obj_free(olockptr);
}
if (lockptr == NULL) {
/* If new lock is not passed - allocate default one. */
rw_obj_alloc(&lockptr, "uobjlk");
}
uo->vmobjlock = lockptr;
}
#ifndef SMALL_KERNEL
/*
* uvm_obj_wire: wire the pages of entire UVM object.
*
* => NOTE: this function should only be used for types of objects
* where PG_RELEASED flag is never set (aobj objects)
* => caller must pass page-aligned start and end values
* => if the caller passes in a pageq pointer, we'll return a list of
* wired pages.
*/
int
uvm_obj_wire(struct uvm_object *uobj, voff_t start, voff_t end,
struct pglist *pageq)
{
int i, npages, left, error;
struct vm_page *pgs[FETCH_PAGECOUNT];
voff_t offset = start;
left = (end - start) >> PAGE_SHIFT;
rw_enter(uobj->vmobjlock, RW_WRITE | RW_DUPOK);
while (left) {
npages = MIN(FETCH_PAGECOUNT, left);
/* Get the pages */
memset(pgs, 0, sizeof(pgs));
error = (*uobj->pgops->pgo_get)(uobj, offset, pgs, &npages, 0,
PROT_READ | PROT_WRITE, MADV_SEQUENTIAL,
PGO_ALLPAGES | PGO_SYNCIO);
if (error)
goto error;
rw_enter(uobj->vmobjlock, RW_WRITE | RW_DUPOK);
for (i = 0; i < npages; i++) {
KASSERT(pgs[i] != NULL);
KASSERT(!(pgs[i]->pg_flags & PG_RELEASED));
if (pgs[i]->pg_flags & PQ_AOBJ) {
atomic_clearbits_int(&pgs[i]->pg_flags,
PG_CLEAN);
uao_dropswap(uobj, i);
}
}
/* Wire the pages */
uvm_lock_pageq();
for (i = 0; i < npages; i++) {
uvm_pagewire(pgs[i]);
if (pageq != NULL)
TAILQ_INSERT_TAIL(pageq, pgs[i], pageq);
}
uvm_unlock_pageq();
/* Unbusy the pages */
uvm_page_unbusy(pgs, npages);
left -= npages;
offset += (voff_t)npages << PAGE_SHIFT;
}
rw_exit(uobj->vmobjlock);
return 0;
error:
/* Unwire the pages which have been wired */
uvm_obj_unwire(uobj, start, offset);
return error;
}
/*
* uvm_obj_unwire: unwire the pages of entire UVM object.
*
* => caller must pass page-aligned start and end values
*/
void
uvm_obj_unwire(struct uvm_object *uobj, voff_t start, voff_t end)
{
struct vm_page *pg;
off_t offset;
rw_enter(uobj->vmobjlock, RW_WRITE | RW_DUPOK);
uvm_lock_pageq();
for (offset = start; offset < end; offset += PAGE_SIZE) {
pg = uvm_pagelookup(uobj, offset);
KASSERT(pg != NULL);
KASSERT(!(pg->pg_flags & PG_RELEASED));
uvm_pageunwire(pg);
}
uvm_unlock_pageq();
rw_exit(uobj->vmobjlock);
}
#endif /* !SMALL_KERNEL */
/*
* uvm_obj_free: free all pages in a uvm object, used by the buffer
* cache to free all pages attached to a buffer.
*/
void
uvm_obj_free(struct uvm_object *uobj)
{
struct vm_page *pg;
struct pglist pgl;
KASSERT(UVM_OBJ_IS_BUFCACHE(uobj));
KERNEL_ASSERT_LOCKED();
TAILQ_INIT(&pgl);
/*
* Extract from rb tree in offset order. The phys addresses
* usually increase in that order, which is better for
* uvm_pglistfree().
*/
RBT_FOREACH(pg, uvm_objtree, &uobj->memt) {
/*
* clear PG_TABLED so we don't do work to remove
* this pg from the uobj we are throwing away
*/
atomic_clearbits_int(&pg->pg_flags, PG_TABLED);
uvm_lock_pageq();
uvm_pageclean(pg);
uvm_unlock_pageq();
TAILQ_INSERT_TAIL(&pgl, pg, pageq);
}
uvm_pglistfree(&pgl);
}
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