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bdef8bf092
capable of being used for things other than swap space allocation, and splvm would have been appropriate for only swap space allocation and other VM things. My commit broke that (and was actually a mistake.)
312 lines
8.1 KiB
C
312 lines
8.1 KiB
C
/*
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* Copyright (c) 1992 William F. Jolitz, TeleMuse
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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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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This software is a component of "386BSD" developed by
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William F. Jolitz, TeleMuse.
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* 4. Neither the name of the developer nor the name "386BSD"
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS A COMPONENT OF 386BSD DEVELOPED BY WILLIAM F. JOLITZ
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* AND IS INTENDED FOR RESEARCH AND EDUCATIONAL PURPOSES ONLY. THIS
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* SOFTWARE SHOULD NOT BE CONSIDERED TO BE A COMMERCIAL PRODUCT.
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* THE DEVELOPER URGES THAT USERS WHO REQUIRE A COMMERCIAL PRODUCT
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* NOT MAKE USE THIS WORK.
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*
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* FOR USERS WHO WISH TO UNDERSTAND THE 386BSD SYSTEM DEVELOPED
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* BY WILLIAM F. JOLITZ, WE RECOMMEND THE USER STUDY WRITTEN
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* REFERENCES SUCH AS THE "PORTING UNIX TO THE 386" SERIES
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* (BEGINNING JANUARY 1991 "DR. DOBBS JOURNAL", USA AND BEGINNING
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* JUNE 1991 "UNIX MAGAZIN", GERMANY) BY WILLIAM F. JOLITZ AND
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* LYNNE GREER JOLITZ, AS WELL AS OTHER BOOKS ON UNIX AND THE
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* ON-LINE 386BSD USER MANUAL BEFORE USE. A BOOK DISCUSSING THE INTERNALS
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* OF 386BSD ENTITLED "386BSD FROM THE INSIDE OUT" WILL BE AVAILABLE LATE 1992.
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*
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* THIS SOFTWARE IS PROVIDED BY THE DEVELOPER ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE DEVELOPER BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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*/
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/*
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* Changes Copyright (C) 1995, David Greenman & John Dyson; This software may
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* be used, modified, copied, distributed, and sold, in both source and
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* binary form provided that the above copyright and these terms are
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* retained. Under no circumstances is the author responsible for the proper
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* functioning of this software, nor does the author assume any responsibility
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* for damages incurred with its use.
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*
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* $Id: subr_rlist.c,v 1.18 1996/10/12 21:35:25 dyson Exp $
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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/rlist.h>
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#include <sys/proc.h>
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#include <vm/vm.h>
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#include <vm/vm_param.h>
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#include <vm/vm_kern.h>
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#include <vm/vm_extern.h>
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/*
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* Resource lists.
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*/
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#define RLIST_MIN 128
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static int rlist_count=0;
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static struct rlist *rlfree;
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static struct rlist *rlist_malloc __P((void));
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static struct rlist *
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rlist_malloc()
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{
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struct rlist *rl;
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int i;
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while( rlist_count < RLIST_MIN) {
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int s = splhigh();
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rl = (struct rlist *)kmem_alloc(kernel_map, PAGE_SIZE);
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splx(s);
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if( !rl)
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break;
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for(i=0;i<(PAGE_SIZE/(sizeof *rl));i++) {
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rl->rl_next = rlfree;
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rlfree = rl;
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rlist_count++;
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rl++;
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}
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}
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if( (rl = rlfree) == 0 )
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panic("Cannot get an rlist entry");
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--rlist_count;
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rlfree = rl->rl_next;
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return rl;
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}
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inline static void
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rlist_mfree( struct rlist *rl)
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{
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rl->rl_next = rlfree;
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rlfree = rl;
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++rlist_count;
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}
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void
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rlist_free(rlh, start, end)
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struct rlisthdr *rlh;
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u_int start, end;
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{
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struct rlist **rlp = &rlh->rlh_list;
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struct rlist *prev_rlp = NULL, *cur_rlp = *rlp, *next_rlp = NULL;
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int s;
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s = splhigh();
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while (rlh->rlh_lock & RLH_LOCKED) {
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rlh->rlh_lock |= RLH_DESIRED;
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tsleep(rlh, PSWP, "rlistf", 0);
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}
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rlh->rlh_lock |= RLH_LOCKED;
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splx(s);
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/*
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* Traverse the list looking for an entry after the one we want
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* to insert.
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*/
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while (cur_rlp != NULL) {
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if (start < cur_rlp->rl_start)
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break;
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#ifdef DIAGNOSTIC
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if (prev_rlp) {
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if (prev_rlp->rl_end + 1 == cur_rlp->rl_start)
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panic("rlist_free: missed coalesce opportunity");
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if (prev_rlp->rl_end == cur_rlp->rl_start)
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panic("rlist_free: entries overlap");
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if (prev_rlp->rl_end > cur_rlp->rl_start)
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panic("entries out of order");
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}
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#endif
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prev_rlp = cur_rlp;
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cur_rlp = cur_rlp->rl_next;
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}
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if (cur_rlp != NULL) {
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if (end >= cur_rlp->rl_start)
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panic("rlist_free: free end overlaps already freed area");
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if (prev_rlp) {
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if (start <= prev_rlp->rl_end)
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panic("rlist_free: free start overlaps already freed area");
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/*
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* Attempt to append
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*/
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if (prev_rlp->rl_end + 1 == start) {
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prev_rlp->rl_end = end;
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/*
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* Attempt to prepend and coalesce
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*/
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if (end + 1 == cur_rlp->rl_start) {
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prev_rlp->rl_end = cur_rlp->rl_end;
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prev_rlp->rl_next = cur_rlp->rl_next;
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rlist_mfree(cur_rlp);
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}
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goto done;
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}
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}
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/*
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* Attempt to prepend
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*/
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if (end + 1 == cur_rlp->rl_start) {
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cur_rlp->rl_start = start;
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goto done;
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}
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}
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/*
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* Reached the end of the list without finding a larger entry.
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* Append to last entry if there is one and it's adjacent.
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*/
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if (prev_rlp) {
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if (start <= prev_rlp->rl_end)
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panic("rlist_free: free start overlaps already freed area at list tail");
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/*
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* Attempt to append
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*/
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if (prev_rlp->rl_end + 1 == start) {
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prev_rlp->rl_end = end;
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goto done;
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}
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}
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/*
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* Could neither append nor prepend; allocate a new entry.
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*/
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next_rlp = cur_rlp;
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cur_rlp = rlist_malloc();
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cur_rlp->rl_start = start;
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cur_rlp->rl_end = end;
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cur_rlp->rl_next = next_rlp;
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if (prev_rlp) {
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prev_rlp->rl_next = cur_rlp;
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} else {
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/*
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* No previous - this entry is the new list head.
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*/
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*rlp = cur_rlp;
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}
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done:
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rlh->rlh_lock &= ~RLH_LOCKED;
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if (rlh->rlh_lock & RLH_DESIRED) {
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wakeup(rlh);
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rlh->rlh_lock &= ~RLH_DESIRED;
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}
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return;
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}
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/*
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* Obtain a region of desired size from a resource list.
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* If nothing available of that size, return 0. Otherwise,
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* return a value of 1 and set resource start location with
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* "*loc". (Note: loc can be zero if we don't wish the value)
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*/
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int
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rlist_alloc (rlh, size, loc)
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struct rlisthdr *rlh;
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unsigned size, *loc;
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{
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struct rlist **rlp = &rlh->rlh_list;
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register struct rlist *lp;
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int s;
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register struct rlist *olp = 0;
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s = splhigh();
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while (rlh->rlh_lock & RLH_LOCKED) {
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rlh->rlh_lock |= RLH_DESIRED;
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tsleep(rlh, PSWP, "rlistf", 0);
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}
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rlh->rlh_lock |= RLH_LOCKED;
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splx(s);
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/* walk list, allocating first thing that's big enough (first fit) */
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for (; *rlp; rlp = &((*rlp)->rl_next))
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if(size <= (*rlp)->rl_end - (*rlp)->rl_start + 1) {
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/* hand it to the caller */
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if (loc) *loc = (*rlp)->rl_start;
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(*rlp)->rl_start += size;
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/* did we eat this element entirely? */
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if ((*rlp)->rl_start > (*rlp)->rl_end) {
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lp = (*rlp)->rl_next;
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rlist_mfree(*rlp);
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/*
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* if the deleted element was in fromt
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* of the list, adjust *rlp, else don't.
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*/
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if (olp) {
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olp->rl_next = lp;
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} else {
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*rlp = lp;
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}
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}
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rlh->rlh_lock &= ~RLH_LOCKED;
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if (rlh->rlh_lock & RLH_DESIRED) {
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wakeup(rlh);
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rlh->rlh_lock &= ~RLH_DESIRED;
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}
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return (1);
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} else {
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olp = *rlp;
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}
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rlh->rlh_lock &= ~RLH_LOCKED;
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if (rlh->rlh_lock & RLH_DESIRED) {
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wakeup(rlh);
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rlh->rlh_lock &= ~RLH_DESIRED;
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}
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/* nothing in list that's big enough */
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return (0);
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}
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/*
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* Finished with this resource list, reclaim all space and
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* mark it as being empty.
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*/
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void
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rlist_destroy (rlh)
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struct rlisthdr *rlh;
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{
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struct rlist **rlp = &rlh->rlh_list;
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struct rlist *lp, *nlp;
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lp = *rlp;
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*rlp = 0;
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for (; lp; lp = nlp) {
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nlp = lp->rl_next;
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rlist_mfree(lp);
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}
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}
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