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uvm_object.c
375 lines (311 loc) · 8.6 KB
/
uvm_object.c
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/* $NetBSD: uvm_object.c,v 1.25 2020/08/15 07:24:09 chs 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
*
* TODO:
* 1. Support PG_RELEASED-using objects
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: uvm_object.c,v 1.25 2020/08/15 07:24:09 chs Exp $");
#ifdef _KERNEL_OPT
#include "opt_ddb.h"
#endif
#include <sys/param.h>
#include <sys/rwlock.h>
#include <sys/queue.h>
#include <uvm/uvm.h>
#include <uvm/uvm_ddb.h>
#include <uvm/uvm_page_array.h>
/* 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 *uo, const struct uvm_pagerops *ops,
bool alock, u_int refs)
{
#if 0 /* notyet */
KASSERT(ops);
#endif
if (alock) {
/* Allocate and assign a lock. */
uo->vmobjlock = rw_obj_alloc();
} else {
/* The lock will need to be set via uvm_obj_setlock(). */
uo->vmobjlock = NULL;
}
uo->pgops = ops;
LIST_INIT(&uo->uo_ubc);
uo->uo_npages = 0;
uo->uo_refs = refs;
radix_tree_init_tree(&uo->uo_pages);
}
/*
* uvm_obj_destroy: destroy UVM memory object.
*/
void
uvm_obj_destroy(struct uvm_object *uo, bool dlock)
{
KASSERT(radix_tree_empty_tree_p(&uo->uo_pages));
/* Purge any UBC entries associated with this object. */
ubc_purge(uo);
/* Destroy the lock, if requested. */
if (dlock) {
rw_obj_free(uo->vmobjlock);
}
radix_tree_fini_tree(&uo->uo_pages);
}
/*
* 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, krwlock_t *lockptr)
{
krwlock_t *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. */
lockptr = rw_obj_alloc();
}
uo->vmobjlock = lockptr;
}
/*
* uvm_obj_wirepages: 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
*/
int
uvm_obj_wirepages(struct uvm_object *uobj, off_t start, off_t end,
struct pglist *list)
{
int i, npages, error;
struct vm_page *pgs[FETCH_PAGECOUNT], *pg = NULL;
off_t offset = start, left;
left = (end - start) >> PAGE_SHIFT;
rw_enter(uobj->vmobjlock, RW_WRITER);
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,
VM_PROT_READ | VM_PROT_WRITE, UVM_ADV_SEQUENTIAL,
PGO_SYNCIO);
if (error)
goto error;
rw_enter(uobj->vmobjlock, RW_WRITER);
for (i = 0; i < npages; i++) {
KASSERT(pgs[i] != NULL);
KASSERT(!(pgs[i]->flags & PG_RELEASED));
/*
* Loan break
*/
if (pgs[i]->loan_count) {
while (pgs[i]->loan_count) {
pg = uvm_loanbreak(pgs[i]);
if (!pg) {
rw_exit(uobj->vmobjlock);
uvm_wait("uobjwirepg");
rw_enter(uobj->vmobjlock, RW_WRITER);
continue;
}
}
pgs[i] = pg;
}
if (pgs[i]->flags & PG_AOBJ) {
uvm_pagemarkdirty(pgs[i],
UVM_PAGE_STATUS_DIRTY);
uao_dropswap(uobj, i);
}
}
/* Wire the pages */
for (i = 0; i < npages; i++) {
uvm_pagelock(pgs[i]);
uvm_pagewire(pgs[i]);
uvm_pageunlock(pgs[i]);
if (list != NULL)
TAILQ_INSERT_TAIL(list, pgs[i], pageq.queue);
}
/* Unbusy the pages */
uvm_page_unbusy(pgs, npages);
left -= npages;
offset += npages << PAGE_SHIFT;
}
rw_exit(uobj->vmobjlock);
return 0;
error:
/* Unwire the pages which has been wired */
uvm_obj_unwirepages(uobj, start, offset);
return error;
}
/*
* uvm_obj_unwirepages: unwire the pages of entire UVM object.
*
* => NOTE: this function should only be used for types of objects
* where PG_RELEASED flag is never set
* => caller must pass page-aligned start and end values
*/
void
uvm_obj_unwirepages(struct uvm_object *uobj, off_t start, off_t end)
{
struct vm_page *pg;
off_t offset;
rw_enter(uobj->vmobjlock, RW_WRITER);
for (offset = start; offset < end; offset += PAGE_SIZE) {
pg = uvm_pagelookup(uobj, offset);
KASSERT(pg != NULL);
KASSERT(!(pg->flags & PG_RELEASED));
uvm_pagelock(pg);
uvm_pageunwire(pg);
uvm_pageunlock(pg);
}
rw_exit(uobj->vmobjlock);
}
static inline bool
uvm_obj_notag_p(struct uvm_object *uobj, int tag)
{
KASSERT(rw_lock_held(uobj->vmobjlock));
return radix_tree_empty_tagged_tree_p(&uobj->uo_pages, tag);
}
bool
uvm_obj_clean_p(struct uvm_object *uobj)
{
return uvm_obj_notag_p(uobj, UVM_PAGE_DIRTY_TAG);
}
bool
uvm_obj_nowriteback_p(struct uvm_object *uobj)
{
return uvm_obj_notag_p(uobj, UVM_PAGE_WRITEBACK_TAG);
}
static inline bool
uvm_obj_page_tag_p(struct vm_page *pg, int tag)
{
struct uvm_object *uobj = pg->uobject;
uint64_t pgidx = pg->offset >> PAGE_SHIFT;
KASSERT(uobj != NULL);
KASSERT(rw_lock_held(uobj->vmobjlock));
return radix_tree_get_tag(&uobj->uo_pages, pgidx, tag) != 0;
}
static inline void
uvm_obj_page_set_tag(struct vm_page *pg, int tag)
{
struct uvm_object *uobj = pg->uobject;
uint64_t pgidx = pg->offset >> PAGE_SHIFT;
KASSERT(uobj != NULL);
KASSERT(rw_write_held(uobj->vmobjlock));
radix_tree_set_tag(&uobj->uo_pages, pgidx, tag);
}
static inline void
uvm_obj_page_clear_tag(struct vm_page *pg, int tag)
{
struct uvm_object *uobj = pg->uobject;
uint64_t pgidx = pg->offset >> PAGE_SHIFT;
KASSERT(uobj != NULL);
KASSERT(rw_write_held(uobj->vmobjlock));
radix_tree_clear_tag(&uobj->uo_pages, pgidx, tag);
}
bool
uvm_obj_page_dirty_p(struct vm_page *pg)
{
return uvm_obj_page_tag_p(pg, UVM_PAGE_DIRTY_TAG);
}
void
uvm_obj_page_set_dirty(struct vm_page *pg)
{
uvm_obj_page_set_tag(pg, UVM_PAGE_DIRTY_TAG);
}
void
uvm_obj_page_clear_dirty(struct vm_page *pg)
{
uvm_obj_page_clear_tag(pg, UVM_PAGE_DIRTY_TAG);
}
bool
uvm_obj_page_writeback_p(struct vm_page *pg)
{
return uvm_obj_page_tag_p(pg, UVM_PAGE_WRITEBACK_TAG);
}
void
uvm_obj_page_set_writeback(struct vm_page *pg)
{
uvm_obj_page_set_tag(pg, UVM_PAGE_WRITEBACK_TAG);
}
void
uvm_obj_page_clear_writeback(struct vm_page *pg)
{
uvm_obj_page_clear_tag(pg, UVM_PAGE_WRITEBACK_TAG);
}
#if defined(DDB) || defined(DEBUGPRINT)
/*
* uvm_object_printit: actually prints the object
*/
void
uvm_object_printit(struct uvm_object *uobj, bool full,
void (*pr)(const char *, ...))
{
struct uvm_page_array a;
struct vm_page *pg;
int cnt = 0;
voff_t off;
(*pr)("OBJECT %p: locked=%d, pgops=%p, npages=%d, ",
uobj, rw_write_held(uobj->vmobjlock), uobj->pgops, uobj->uo_npages);
if (UVM_OBJ_IS_KERN_OBJECT(uobj))
(*pr)("refs=<SYSTEM>\n");
else
(*pr)("refs=%d\n", uobj->uo_refs);
if (!full) {
return;
}
(*pr)(" PAGES <pg,offset>:\n ");
uvm_page_array_init(&a, uobj, 0);
off = 0;
while ((pg = uvm_page_array_fill_and_peek(&a, off, 0)) != NULL) {
cnt++;
(*pr)("<%p,0x%llx> ", pg, (long long)pg->offset);
if ((cnt % 3) == 0) {
(*pr)("\n ");
}
off = pg->offset + PAGE_SIZE;
uvm_page_array_advance(&a);
}
if ((cnt % 3) != 0) {
(*pr)("\n");
}
uvm_page_array_fini(&a);
}
#endif /* DDB || DEBUGPRINT */