248 lines
6.3 KiB
C
248 lines
6.3 KiB
C
/* $OpenBSD: uvm_object.c,v 1.25 2022/02/21 16:08:36 kn Exp $ */
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/*
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* Copyright (c) 2006, 2010, 2019 The NetBSD Foundation, Inc.
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* All rights reserved.
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*
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* This code is derived from software contributed to The NetBSD Foundation
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* by Mindaugas Rasiukevicius.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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/*
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* uvm_object.c: operate with memory objects
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*
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*/
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/mman.h>
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#include <sys/atomic.h>
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#include <sys/rwlock.h>
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#include <uvm/uvm.h>
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/* Dummy object used by some pmaps for sanity checks. */
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const struct uvm_pagerops pmap_pager = {
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/* nothing */
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};
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/* Dummy object used by the buffer cache for sanity checks. */
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const struct uvm_pagerops bufcache_pager = {
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/* nothing */
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};
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/* Page count to fetch per single step. */
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#define FETCH_PAGECOUNT 16
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/*
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* uvm_obj_init: initialize UVM memory object.
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*/
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void
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uvm_obj_init(struct uvm_object *uobj, const struct uvm_pagerops *pgops, int refs)
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{
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int alock;
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alock = ((pgops != NULL) && (pgops != &pmap_pager) &&
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(pgops != &bufcache_pager) && (refs != UVM_OBJ_KERN));
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if (alock) {
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/* Allocate and assign a lock. */
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rw_obj_alloc(&uobj->vmobjlock, "uobjlk");
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} else {
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/* The lock will need to be set via uvm_obj_setlock(). */
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uobj->vmobjlock = NULL;
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}
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uobj->pgops = pgops;
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RBT_INIT(uvm_objtree, &uobj->memt);
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uobj->uo_npages = 0;
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uobj->uo_refs = refs;
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}
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/*
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* uvm_obj_destroy: destroy UVM memory object.
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*/
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void
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uvm_obj_destroy(struct uvm_object *uo)
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{
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KASSERT(RBT_EMPTY(uvm_objtree, &uo->memt));
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rw_obj_free(uo->vmobjlock);
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}
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/*
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* uvm_obj_setlock: assign a vmobjlock to the UVM object.
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*
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* => Caller is responsible to ensure that UVM objects is not use.
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* => Only dynamic lock may be previously set. We drop the reference then.
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*/
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void
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uvm_obj_setlock(struct uvm_object *uo, struct rwlock *lockptr)
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{
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struct rwlock *olockptr = uo->vmobjlock;
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if (olockptr) {
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/* Drop the reference on the old lock. */
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rw_obj_free(olockptr);
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}
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if (lockptr == NULL) {
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/* If new lock is not passed - allocate default one. */
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rw_obj_alloc(&lockptr, "uobjlk");
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}
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uo->vmobjlock = lockptr;
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}
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#ifndef SMALL_KERNEL
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/*
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* uvm_obj_wire: wire the pages of entire UVM object.
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*
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* => NOTE: this function should only be used for types of objects
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* where PG_RELEASED flag is never set (aobj objects)
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* => caller must pass page-aligned start and end values
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* => if the caller passes in a pageq pointer, we'll return a list of
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* wired pages.
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*/
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int
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uvm_obj_wire(struct uvm_object *uobj, voff_t start, voff_t end,
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struct pglist *pageq)
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{
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int i, npages, left, error;
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struct vm_page *pgs[FETCH_PAGECOUNT];
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voff_t offset = start;
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left = (end - start) >> PAGE_SHIFT;
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rw_enter(uobj->vmobjlock, RW_WRITE | RW_DUPOK);
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while (left) {
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npages = MIN(FETCH_PAGECOUNT, left);
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/* Get the pages */
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memset(pgs, 0, sizeof(pgs));
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error = (*uobj->pgops->pgo_get)(uobj, offset, pgs, &npages, 0,
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PROT_READ | PROT_WRITE, MADV_SEQUENTIAL,
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PGO_ALLPAGES | PGO_SYNCIO);
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if (error)
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goto error;
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rw_enter(uobj->vmobjlock, RW_WRITE | RW_DUPOK);
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for (i = 0; i < npages; i++) {
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KASSERT(pgs[i] != NULL);
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KASSERT(!(pgs[i]->pg_flags & PG_RELEASED));
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if (pgs[i]->pg_flags & PQ_AOBJ) {
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atomic_clearbits_int(&pgs[i]->pg_flags,
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PG_CLEAN);
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uao_dropswap(uobj, i);
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}
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}
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/* Wire the pages */
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uvm_lock_pageq();
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for (i = 0; i < npages; i++) {
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uvm_pagewire(pgs[i]);
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if (pageq != NULL)
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TAILQ_INSERT_TAIL(pageq, pgs[i], pageq);
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}
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uvm_unlock_pageq();
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/* Unbusy the pages */
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uvm_page_unbusy(pgs, npages);
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left -= npages;
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offset += (voff_t)npages << PAGE_SHIFT;
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}
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rw_exit(uobj->vmobjlock);
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return 0;
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error:
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/* Unwire the pages which have been wired */
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uvm_obj_unwire(uobj, start, offset);
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return error;
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}
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/*
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* uvm_obj_unwire: unwire the pages of entire UVM object.
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*
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* => caller must pass page-aligned start and end values
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*/
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void
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uvm_obj_unwire(struct uvm_object *uobj, voff_t start, voff_t end)
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{
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struct vm_page *pg;
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off_t offset;
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rw_enter(uobj->vmobjlock, RW_WRITE | RW_DUPOK);
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uvm_lock_pageq();
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for (offset = start; offset < end; offset += PAGE_SIZE) {
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pg = uvm_pagelookup(uobj, offset);
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KASSERT(pg != NULL);
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KASSERT(!(pg->pg_flags & PG_RELEASED));
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uvm_pageunwire(pg);
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}
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uvm_unlock_pageq();
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rw_exit(uobj->vmobjlock);
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}
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#endif /* !SMALL_KERNEL */
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/*
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* uvm_obj_free: free all pages in a uvm object, used by the buffer
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* cache to free all pages attached to a buffer.
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*/
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void
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uvm_obj_free(struct uvm_object *uobj)
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{
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struct vm_page *pg;
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struct pglist pgl;
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KASSERT(UVM_OBJ_IS_BUFCACHE(uobj));
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KERNEL_ASSERT_LOCKED();
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TAILQ_INIT(&pgl);
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/*
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* Extract from rb tree in offset order. The phys addresses
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* usually increase in that order, which is better for
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* uvm_pglistfree().
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*/
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RBT_FOREACH(pg, uvm_objtree, &uobj->memt) {
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/*
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* clear PG_TABLED so we don't do work to remove
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* this pg from the uobj we are throwing away
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*/
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atomic_clearbits_int(&pg->pg_flags, PG_TABLED);
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uvm_lock_pageq();
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uvm_pageclean(pg);
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uvm_unlock_pageq();
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TAILQ_INSERT_TAIL(&pgl, pg, pageq);
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}
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uvm_pglistfree(&pgl);
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}
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