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/* $OpenBSD: uvm_anon.c,v 1.55 2023/04/11 00:45:09 jsg Exp $ */
/* $NetBSD: uvm_anon.c,v 1.10 2000/11/25 06:27:59 chs Exp $ */
/*
* Copyright (c) 1997 Charles D. Cranor and Washington University.
* All rights reserved.
*
* 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 AUTHOR ``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 AUTHOR 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_anon.c: uvm anon ops
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/malloc.h>
#include <sys/pool.h>
#include <sys/kernel.h>
#include <sys/atomic.h>
#include <uvm/uvm.h>
#include <uvm/uvm_swap.h>
struct pool uvm_anon_pool;
void
uvm_anon_init(void)
{
pool_init(&uvm_anon_pool, sizeof(struct vm_anon), 0, IPL_MPFLOOR,
PR_WAITOK, "anonpl", NULL);
pool_sethiwat(&uvm_anon_pool, uvmexp.free / 16);
}
/*
* uvm_analloc: allocate a new anon.
*
* => anon will have no lock associated.
*/
struct vm_anon *
uvm_analloc(void)
{
struct vm_anon *anon;
anon = pool_get(&uvm_anon_pool, PR_NOWAIT);
if (anon) {
anon->an_lock = NULL;
anon->an_ref = 1;
anon->an_page = NULL;
anon->an_swslot = 0;
}
return anon;
}
/*
* uvm_anfree_list: free a single anon structure
*
* => anon must be removed from the amap (if anon was in an amap).
* => amap must be locked, if anon was owned by amap.
* => we may lock the pageq's.
*/
void
uvm_anfree_list(struct vm_anon *anon, struct pglist *pgl)
{
struct vm_page *pg = anon->an_page;
KASSERT(anon->an_lock == NULL || rw_write_held(anon->an_lock));
KASSERT(anon->an_ref == 0);
/*
* Dispose of the page, if it is resident.
*/
if (pg != NULL) {
KASSERT(anon->an_lock != NULL);
/*
* If the page is busy, mark it as PG_RELEASED, so
* that uvm_anon_release(9) would release it later.
*/
if ((pg->pg_flags & PG_BUSY) != 0) {
atomic_setbits_int(&pg->pg_flags, PG_RELEASED);
rw_obj_hold(anon->an_lock);
return;
}
pmap_page_protect(pg, PROT_NONE);
if (pgl != NULL) {
/*
* clean page, and put it on pglist
* for later freeing.
*/
uvm_lock_pageq();
uvm_pageclean(pg);
uvm_unlock_pageq();
TAILQ_INSERT_HEAD(pgl, pg, pageq);
} else {
uvm_lock_pageq(); /* lock out pagedaemon */
uvm_pagefree(pg); /* bye bye */
uvm_unlock_pageq(); /* free the daemon */
}
} else {
if (anon->an_swslot != 0) {
/* This page is no longer only in swap. */
KASSERT(uvmexp.swpgonly > 0);
atomic_dec_int(&uvmexp.swpgonly);
}
}
anon->an_lock = NULL;
/*
* Free any swap resources, leave a page replacement hint.
*/
uvm_anon_dropswap(anon);
KASSERT(anon->an_page == NULL);
KASSERT(anon->an_swslot == 0);
pool_put(&uvm_anon_pool, anon);
}
/*
* uvm_anwait: wait for memory to become available to allocate an anon.
*/
void
uvm_anwait(void)
{
struct vm_anon *anon;
/* XXX: Want something like pool_wait()? */
anon = pool_get(&uvm_anon_pool, PR_WAITOK);
pool_put(&uvm_anon_pool, anon);
}
/*
* uvm_anon_pagein: fetch an anon's page.
*
* => anon must be locked, and is unlocked upon return.
* => returns true if pagein was aborted due to lack of memory.
*/
boolean_t
uvm_anon_pagein(struct vm_amap *amap, struct vm_anon *anon)
{
struct vm_page *pg;
int rv;
KASSERT(rw_write_held(anon->an_lock));
KASSERT(anon->an_lock == amap->am_lock);
/*
* Get the page of the anon.
*/
rv = uvmfault_anonget(NULL, amap, anon);
switch (rv) {
case VM_PAGER_OK:
KASSERT(rw_write_held(anon->an_lock));
break;
case VM_PAGER_ERROR:
case VM_PAGER_REFAULT:
/*
* Nothing more to do on errors.
* VM_PAGER_REFAULT means that the anon was freed.
*/
return FALSE;
default:
#ifdef DIAGNOSTIC
panic("anon_pagein: uvmfault_anonget -> %d", rv);
#else
return FALSE;
#endif
}
/*
* Mark the page as dirty and clear its swslot.
*/
pg = anon->an_page;
if (anon->an_swslot > 0) {
uvm_swap_free(anon->an_swslot, 1);
}
anon->an_swslot = 0;
atomic_clearbits_int(&pg->pg_flags, PG_CLEAN);
/*
* Deactivate the page (to put it on a page queue).
*/
pmap_clear_reference(pg);
pmap_page_protect(pg, PROT_NONE);
uvm_lock_pageq();
uvm_pagedeactivate(pg);
uvm_unlock_pageq();
rw_exit(anon->an_lock);
return FALSE;
}
/*
* uvm_anon_dropswap: release any swap resources from this anon.
*
* => anon must be locked or have a reference count of 0.
*/
void
uvm_anon_dropswap(struct vm_anon *anon)
{
KASSERT(anon->an_ref == 0 || rw_lock_held(anon->an_lock));
if (anon->an_swslot == 0)
return;
uvm_swap_free(anon->an_swslot, 1);
anon->an_swslot = 0;
}
/*
* uvm_anon_release: release an anon and its page.
*
* => anon should not have any references.
* => anon must be locked.
*/
void
uvm_anon_release(struct vm_anon *anon)
{
struct vm_page *pg = anon->an_page;
struct rwlock *lock;
KASSERT(rw_write_held(anon->an_lock));
KASSERT(pg != NULL);
KASSERT((pg->pg_flags & PG_RELEASED) != 0);
KASSERT((pg->pg_flags & PG_BUSY) != 0);
KASSERT(pg->uobject == NULL);
KASSERT(pg->uanon == anon);
KASSERT(anon->an_ref == 0);
uvm_lock_pageq();
uvm_pagefree(pg);
uvm_unlock_pageq();
KASSERT(anon->an_page == NULL);
lock = anon->an_lock;
uvm_anfree(anon);
rw_exit(lock);
/* Note: extra reference is held for PG_RELEASED case. */
rw_obj_free(lock);
}
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