269 lines
6.3 KiB
C
269 lines
6.3 KiB
C
/* $OpenBSD: uvm_anon.c,v 1.58 2024/04/06 10:59:52 mpi Exp $ */
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/* $NetBSD: uvm_anon.c,v 1.10 2000/11/25 06:27:59 chs Exp $ */
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/*
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* Copyright (c) 1997 Charles D. Cranor and Washington University.
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* All rights reserved.
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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 AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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/*
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* uvm_anon.c: uvm anon ops
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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/malloc.h>
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#include <sys/pool.h>
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#include <sys/kernel.h>
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#include <sys/atomic.h>
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#include <uvm/uvm.h>
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#include <uvm/uvm_swap.h>
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struct pool uvm_anon_pool;
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void
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uvm_anon_init(void)
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{
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pool_init(&uvm_anon_pool, sizeof(struct vm_anon), 0, IPL_MPFLOOR,
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PR_WAITOK, "anonpl", NULL);
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pool_sethiwat(&uvm_anon_pool, uvmexp.free / 16);
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}
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/*
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* uvm_analloc: allocate a new anon.
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*
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* => anon will have no lock associated.
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*/
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struct vm_anon *
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uvm_analloc(void)
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{
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struct vm_anon *anon;
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anon = pool_get(&uvm_anon_pool, PR_NOWAIT);
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if (anon) {
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anon->an_lock = NULL;
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anon->an_ref = 1;
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anon->an_page = NULL;
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anon->an_swslot = 0;
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}
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return anon;
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}
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/*
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* uvm_anfree_list: free a single anon structure
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*
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* => anon must be removed from the amap (if anon was in an amap).
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* => amap must be locked, if anon was owned by amap.
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* => we may lock the pageq's.
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*/
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void
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uvm_anfree_list(struct vm_anon *anon, struct pglist *pgl)
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{
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struct vm_page *pg = anon->an_page;
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KASSERT(anon->an_lock == NULL || rw_write_held(anon->an_lock));
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KASSERT(anon->an_ref == 0);
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/*
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* Dispose of the page, if it is resident.
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*/
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if (pg != NULL) {
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KASSERT(anon->an_lock != NULL);
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/*
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* If the page is busy, mark it as PG_RELEASED, so
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* that uvm_anon_release(9) would release it later.
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*/
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if ((pg->pg_flags & PG_BUSY) != 0) {
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atomic_setbits_int(&pg->pg_flags, PG_RELEASED);
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rw_obj_hold(anon->an_lock);
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return;
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}
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pmap_page_protect(pg, PROT_NONE);
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if (pgl != NULL) {
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/*
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* clean page, and put it on pglist
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* for later freeing.
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*/
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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_HEAD(pgl, pg, pageq);
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} else {
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uvm_lock_pageq(); /* lock out pagedaemon */
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uvm_pagefree(pg); /* bye bye */
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uvm_unlock_pageq(); /* free the daemon */
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}
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} else {
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if (anon->an_swslot != 0 && anon->an_swslot != SWSLOT_BAD) {
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/* This page is no longer only in swap. */
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KASSERT(uvmexp.swpgonly > 0);
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atomic_dec_int(&uvmexp.swpgonly);
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}
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}
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anon->an_lock = NULL;
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/*
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* Free any swap resources, leave a page replacement hint.
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*/
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uvm_anon_dropswap(anon);
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KASSERT(anon->an_page == NULL);
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KASSERT(anon->an_swslot == 0);
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pool_put(&uvm_anon_pool, anon);
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}
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/*
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* uvm_anwait: wait for memory to become available to allocate an anon.
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*/
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void
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uvm_anwait(void)
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{
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struct vm_anon *anon;
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/* XXX: Want something like pool_wait()? */
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anon = pool_get(&uvm_anon_pool, PR_WAITOK);
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pool_put(&uvm_anon_pool, anon);
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}
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/*
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* uvm_anon_pagein: fetch an anon's page.
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*
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* => anon must be locked, and is unlocked upon return.
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* => returns true if pagein was aborted due to lack of memory.
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*/
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boolean_t
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uvm_anon_pagein(struct vm_amap *amap, struct vm_anon *anon)
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{
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struct vm_page *pg;
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int rv;
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KASSERT(rw_write_held(anon->an_lock));
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KASSERT(anon->an_lock == amap->am_lock);
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/*
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* Get the page of the anon.
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*/
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rv = uvmfault_anonget(NULL, amap, anon);
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switch (rv) {
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case VM_PAGER_OK:
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KASSERT(rw_write_held(anon->an_lock));
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break;
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case VM_PAGER_ERROR:
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case VM_PAGER_REFAULT:
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/*
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* Nothing more to do on errors.
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* VM_PAGER_REFAULT means that the anon was freed.
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*/
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return FALSE;
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default:
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#ifdef DIAGNOSTIC
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panic("anon_pagein: uvmfault_anonget -> %d", rv);
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#else
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return FALSE;
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#endif
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}
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/*
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* Mark the page as dirty and clear its swslot.
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*/
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pg = anon->an_page;
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if (anon->an_swslot > 0) {
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uvm_swap_free(anon->an_swslot, 1);
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}
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anon->an_swslot = 0;
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atomic_clearbits_int(&pg->pg_flags, PG_CLEAN);
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/*
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* Deactivate the page (to put it on a page queue).
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*/
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pmap_clear_reference(pg);
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pmap_page_protect(pg, PROT_NONE);
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uvm_lock_pageq();
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uvm_pagedeactivate(pg);
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uvm_unlock_pageq();
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rw_exit(anon->an_lock);
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return FALSE;
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}
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/*
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* uvm_anon_dropswap: release any swap resources from this anon.
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*
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* => anon must be locked or have a reference count of 0.
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*/
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void
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uvm_anon_dropswap(struct vm_anon *anon)
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{
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KASSERT(anon->an_ref == 0 || rw_lock_held(anon->an_lock));
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if (anon->an_swslot == 0)
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return;
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uvm_swap_free(anon->an_swslot, 1);
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anon->an_swslot = 0;
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}
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/*
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* uvm_anon_release: release an anon and its page.
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*
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* => anon should not have any references.
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* => anon must be locked.
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*/
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void
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uvm_anon_release(struct vm_anon *anon)
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{
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struct vm_page *pg = anon->an_page;
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struct rwlock *lock;
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KASSERT(rw_write_held(anon->an_lock));
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KASSERT(pg != NULL);
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KASSERT((pg->pg_flags & PG_RELEASED) != 0);
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KASSERT((pg->pg_flags & PG_BUSY) != 0);
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KASSERT(pg->uobject == NULL);
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KASSERT(pg->uanon == anon);
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KASSERT(anon->an_ref == 0);
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uvm_lock_pageq();
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pmap_page_protect(pg, PROT_NONE);
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uvm_pagefree(pg);
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uvm_unlock_pageq();
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KASSERT(anon->an_page == NULL);
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lock = anon->an_lock;
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uvm_anon_dropswap(anon);
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pool_put(&uvm_anon_pool, anon);
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rw_exit(lock);
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/* Note: extra reference is held for PG_RELEASED case. */
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rw_obj_free(lock);
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}
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