869 lines
21 KiB
C
869 lines
21 KiB
C
/* $NetBSD: uvm_pdaemon.c,v 1.39 2001/09/30 02:57:34 chs Exp $ */
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/*
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* Copyright (c) 1997 Charles D. Cranor and Washington University.
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* Copyright (c) 1991, 1993, The Regents of the University of California.
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*
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* All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* The Mach Operating System project at Carnegie-Mellon University.
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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 product includes software developed by Charles D. Cranor,
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* Washington University, the University of California, Berkeley and
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* its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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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 PROVIDED BY THE REGENTS AND CONTRIBUTORS ``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 REGENTS OR CONTRIBUTORS 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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* @(#)vm_pageout.c 8.5 (Berkeley) 2/14/94
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* from: Id: uvm_pdaemon.c,v 1.1.2.32 1998/02/06 05:26:30 chs Exp
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*
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*
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* Copyright (c) 1987, 1990 Carnegie-Mellon University.
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* All rights reserved.
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*
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* Permission to use, copy, modify and distribute this software and
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* its documentation is hereby granted, provided that both the copyright
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* notice and this permission notice appear in all copies of the
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* software, derivative works or modified versions, and any portions
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* thereof, and that both notices appear in supporting documentation.
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*
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* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
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* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
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* FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
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*
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* Carnegie Mellon requests users of this software to return to
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*
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* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
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* School of Computer Science
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* Carnegie Mellon University
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* Pittsburgh PA 15213-3890
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*
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* any improvements or extensions that they make and grant Carnegie the
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* rights to redistribute these changes.
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*/
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#include "opt_uvmhist.h"
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/*
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* uvm_pdaemon.c: the page daemon
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*/
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#include <sys/param.h>
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#include <sys/proc.h>
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#include <sys/systm.h>
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#include <sys/kernel.h>
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#include <sys/pool.h>
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#include <sys/buf.h>
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#include <sys/vnode.h>
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#include <uvm/uvm.h>
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/*
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* UVMPD_NUMDIRTYREACTS is how many dirty pages the pagedeamon will reactivate
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* in a pass thru the inactive list when swap is full. the value should be
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* "small"... if it's too large we'll cycle the active pages thru the inactive
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* queue too quickly to for them to be referenced and avoid being freed.
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*/
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#define UVMPD_NUMDIRTYREACTS 16
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/*
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* local prototypes
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*/
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void uvmpd_scan __P((void));
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boolean_t uvmpd_scan_inactive __P((struct pglist *));
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void uvmpd_tune __P((void));
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/*
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* uvm_wait: wait (sleep) for the page daemon to free some pages
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*
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* => should be called with all locks released
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* => should _not_ be called by the page daemon (to avoid deadlock)
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*/
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void
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uvm_wait(wmsg)
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const char *wmsg;
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{
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int timo = 0;
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int s = splbio();
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/*
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* check for page daemon going to sleep (waiting for itself)
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*/
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if (curproc == uvm.pagedaemon_proc && uvmexp.paging == 0) {
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/*
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* now we have a problem: the pagedaemon wants to go to
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* sleep until it frees more memory. but how can it
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* free more memory if it is asleep? that is a deadlock.
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* we have two options:
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* [1] panic now
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* [2] put a timeout on the sleep, thus causing the
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* pagedaemon to only pause (rather than sleep forever)
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*
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* note that option [2] will only help us if we get lucky
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* and some other process on the system breaks the deadlock
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* by exiting or freeing memory (thus allowing the pagedaemon
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* to continue). for now we panic if DEBUG is defined,
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* otherwise we hope for the best with option [2] (better
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* yet, this should never happen in the first place!).
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*/
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printf("pagedaemon: deadlock detected!\n");
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timo = hz >> 3; /* set timeout */
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#if defined(DEBUG)
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/* DEBUG: panic so we can debug it */
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panic("pagedaemon deadlock");
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#endif
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}
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simple_lock(&uvm.pagedaemon_lock);
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wakeup(&uvm.pagedaemon); /* wake the daemon! */
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UVM_UNLOCK_AND_WAIT(&uvmexp.free, &uvm.pagedaemon_lock, FALSE, wmsg,
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timo);
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splx(s);
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}
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/*
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* uvmpd_tune: tune paging parameters
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*
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* => called when ever memory is added (or removed?) to the system
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* => caller must call with page queues locked
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*/
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void
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uvmpd_tune(void)
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{
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UVMHIST_FUNC("uvmpd_tune"); UVMHIST_CALLED(pdhist);
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uvmexp.freemin = uvmexp.npages / 20;
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/* between 16k and 256k */
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/* XXX: what are these values good for? */
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uvmexp.freemin = MAX(uvmexp.freemin, (16*1024) >> PAGE_SHIFT);
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uvmexp.freemin = MIN(uvmexp.freemin, (256*1024) >> PAGE_SHIFT);
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/* Make sure there's always a user page free. */
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if (uvmexp.freemin < uvmexp.reserve_kernel + 1)
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uvmexp.freemin = uvmexp.reserve_kernel + 1;
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uvmexp.freetarg = (uvmexp.freemin * 4) / 3;
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if (uvmexp.freetarg <= uvmexp.freemin)
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uvmexp.freetarg = uvmexp.freemin + 1;
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/* uvmexp.inactarg: computed in main daemon loop */
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uvmexp.wiredmax = uvmexp.npages / 3;
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UVMHIST_LOG(pdhist, "<- done, freemin=%d, freetarg=%d, wiredmax=%d",
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uvmexp.freemin, uvmexp.freetarg, uvmexp.wiredmax, 0);
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}
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/*
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* uvm_pageout: the main loop for the pagedaemon
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*/
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void
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uvm_pageout(void *arg)
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{
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int npages = 0;
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UVMHIST_FUNC("uvm_pageout"); UVMHIST_CALLED(pdhist);
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UVMHIST_LOG(pdhist,"<starting uvm pagedaemon>", 0, 0, 0, 0);
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/*
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* ensure correct priority and set paging parameters...
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*/
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uvm.pagedaemon_proc = curproc;
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uvm_lock_pageq();
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npages = uvmexp.npages;
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uvmpd_tune();
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uvm_unlock_pageq();
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/*
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* main loop
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*/
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for (;;) {
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simple_lock(&uvm.pagedaemon_lock);
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UVMHIST_LOG(pdhist," <<SLEEPING>>",0,0,0,0);
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UVM_UNLOCK_AND_WAIT(&uvm.pagedaemon,
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&uvm.pagedaemon_lock, FALSE, "pgdaemon", 0);
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uvmexp.pdwoke++;
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UVMHIST_LOG(pdhist," <<WOKE UP>>",0,0,0,0);
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/*
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* now lock page queues and recompute inactive count
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*/
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uvm_lock_pageq();
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if (npages != uvmexp.npages) { /* check for new pages? */
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npages = uvmexp.npages;
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uvmpd_tune();
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}
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uvmexp.inactarg = (uvmexp.active + uvmexp.inactive) / 3;
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if (uvmexp.inactarg <= uvmexp.freetarg) {
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uvmexp.inactarg = uvmexp.freetarg + 1;
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}
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UVMHIST_LOG(pdhist," free/ftarg=%d/%d, inact/itarg=%d/%d",
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uvmexp.free, uvmexp.freetarg, uvmexp.inactive,
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uvmexp.inactarg);
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/*
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* scan if needed
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*/
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if (uvmexp.free + uvmexp.paging < uvmexp.freetarg ||
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uvmexp.inactive < uvmexp.inactarg) {
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uvmpd_scan();
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}
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/*
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* if there's any free memory to be had,
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* wake up any waiters.
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*/
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if (uvmexp.free > uvmexp.reserve_kernel ||
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uvmexp.paging == 0) {
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wakeup(&uvmexp.free);
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}
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/*
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* scan done. unlock page queues (the only lock we are holding)
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*/
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uvm_unlock_pageq();
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/*
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* drain pool resources now that we're not holding any locks
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*/
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pool_drain(0);
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}
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/*NOTREACHED*/
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}
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/*
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* uvm_aiodone_daemon: main loop for the aiodone daemon.
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*/
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void
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uvm_aiodone_daemon(void *arg)
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{
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int s, free;
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struct buf *bp, *nbp;
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UVMHIST_FUNC("uvm_aiodoned"); UVMHIST_CALLED(pdhist);
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for (;;) {
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/*
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* carefully attempt to go to sleep (without losing "wakeups"!).
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* we need splbio because we want to make sure the aio_done list
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* is totally empty before we go to sleep.
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*/
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s = splbio();
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simple_lock(&uvm.aiodoned_lock);
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if (TAILQ_FIRST(&uvm.aio_done) == NULL) {
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UVMHIST_LOG(pdhist," <<SLEEPING>>",0,0,0,0);
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UVM_UNLOCK_AND_WAIT(&uvm.aiodoned,
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&uvm.aiodoned_lock, FALSE, "aiodoned", 0);
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UVMHIST_LOG(pdhist," <<WOKE UP>>",0,0,0,0);
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/* relock aiodoned_lock, still at splbio */
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simple_lock(&uvm.aiodoned_lock);
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}
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/*
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* check for done aio structures
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*/
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bp = TAILQ_FIRST(&uvm.aio_done);
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if (bp) {
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TAILQ_INIT(&uvm.aio_done);
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}
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simple_unlock(&uvm.aiodoned_lock);
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splx(s);
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/*
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* process each i/o that's done.
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*/
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free = uvmexp.free;
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while (bp != NULL) {
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nbp = TAILQ_NEXT(bp, b_freelist);
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(*bp->b_iodone)(bp);
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bp = nbp;
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}
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if (free <= uvmexp.reserve_kernel) {
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s = uvm_lock_fpageq();
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wakeup(&uvm.pagedaemon);
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uvm_unlock_fpageq(s);
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} else {
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simple_lock(&uvm.pagedaemon_lock);
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wakeup(&uvmexp.free);
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simple_unlock(&uvm.pagedaemon_lock);
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}
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}
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}
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/*
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* uvmpd_scan_inactive: scan an inactive list for pages to clean or free.
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*
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* => called with page queues locked
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* => we work on meeting our free target by converting inactive pages
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* into free pages.
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* => we handle the building of swap-backed clusters
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* => we return TRUE if we are exiting because we met our target
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*/
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boolean_t
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uvmpd_scan_inactive(pglst)
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struct pglist *pglst;
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{
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boolean_t retval = FALSE; /* assume we haven't hit target */
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int error;
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struct vm_page *p, *nextpg;
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struct uvm_object *uobj;
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struct vm_anon *anon;
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struct vm_page *swpps[MAXBSIZE >> PAGE_SHIFT];
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struct simplelock *slock;
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int swnpages, swcpages;
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int swslot;
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int dirtyreacts, t, result;
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UVMHIST_FUNC("uvmpd_scan_inactive"); UVMHIST_CALLED(pdhist);
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/*
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* swslot is non-zero if we are building a swap cluster. we want
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* to stay in the loop while we have a page to scan or we have
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* a swap-cluster to build.
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*/
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swslot = 0;
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swnpages = swcpages = 0;
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dirtyreacts = 0;
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for (p = TAILQ_FIRST(pglst); p != NULL || swslot != 0; p = nextpg) {
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uobj = NULL;
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anon = NULL;
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if (p) {
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/*
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* see if we've met the free target.
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*/
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if (uvmexp.free + uvmexp.paging >=
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uvmexp.freetarg << 2 ||
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dirtyreacts == UVMPD_NUMDIRTYREACTS) {
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UVMHIST_LOG(pdhist," met free target: "
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"exit loop", 0, 0, 0, 0);
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retval = TRUE;
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if (swslot == 0) {
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/* exit now if no swap-i/o pending */
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break;
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}
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/* set p to null to signal final swap i/o */
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p = NULL;
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nextpg = NULL;
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}
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}
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if (p) { /* if (we have a new page to consider) */
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/*
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* we are below target and have a new page to consider.
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*/
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uvmexp.pdscans++;
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nextpg = TAILQ_NEXT(p, pageq);
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/*
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* move referenced pages back to active queue and
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* skip to next page.
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*/
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if (pmap_clear_reference(p)) {
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uvm_pageactivate(p);
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uvmexp.pdreact++;
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continue;
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}
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anon = p->uanon;
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uobj = p->uobject;
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/*
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* enforce the minimum thresholds on different
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* types of memory usage. if reusing the current
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* page would reduce that type of usage below its
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* minimum, reactivate the page instead and move
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* on to the next page.
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*/
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t = uvmexp.active + uvmexp.inactive + uvmexp.free;
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if (anon &&
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uvmexp.anonpages <= (t * uvmexp.anonmin) >> 8) {
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uvm_pageactivate(p);
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uvmexp.pdreanon++;
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continue;
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}
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if (uobj && UVM_OBJ_IS_VTEXT(uobj) &&
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uvmexp.vtextpages <= (t * uvmexp.vtextmin) >> 8) {
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uvm_pageactivate(p);
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uvmexp.pdrevtext++;
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continue;
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}
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if (uobj && UVM_OBJ_IS_VNODE(uobj) &&
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!UVM_OBJ_IS_VTEXT(uobj) &&
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uvmexp.vnodepages <= (t * uvmexp.vnodemin) >> 8) {
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uvm_pageactivate(p);
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uvmexp.pdrevnode++;
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continue;
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}
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/*
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* first we attempt to lock the object that this page
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* belongs to. if our attempt fails we skip on to
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* the next page (no harm done). it is important to
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* "try" locking the object as we are locking in the
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* wrong order (pageq -> object) and we don't want to
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* deadlock.
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*
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* the only time we expect to see an ownerless page
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* (i.e. a page with no uobject and !PQ_ANON) is if an
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* anon has loaned a page from a uvm_object and the
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* uvm_object has dropped the ownership. in that
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* case, the anon can "take over" the loaned page
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* and make it its own.
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*/
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/* is page part of an anon or ownerless ? */
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if ((p->pqflags & PQ_ANON) || uobj == NULL) {
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KASSERT(anon != NULL);
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slock = &anon->an_lock;
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if (!simple_lock_try(slock)) {
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/* lock failed, skip this page */
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continue;
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}
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/*
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* if the page is ownerless, claim it in the
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* name of "anon"!
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*/
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if ((p->pqflags & PQ_ANON) == 0) {
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KASSERT(p->loan_count > 0);
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p->loan_count--;
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p->pqflags |= PQ_ANON;
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/* anon now owns it */
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}
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if (p->flags & PG_BUSY) {
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simple_unlock(slock);
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uvmexp.pdbusy++;
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continue;
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}
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uvmexp.pdanscan++;
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} else {
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KASSERT(uobj != NULL);
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slock = &uobj->vmobjlock;
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if (!simple_lock_try(slock)) {
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continue;
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}
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if (p->flags & PG_BUSY) {
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simple_unlock(slock);
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uvmexp.pdbusy++;
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continue;
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}
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uvmexp.pdobscan++;
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}
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/*
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* we now have the object and the page queues locked.
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* if the page is not swap-backed, call the object's
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* pager to flush and free the page.
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*/
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if ((p->pqflags & PQ_SWAPBACKED) == 0) {
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uvm_unlock_pageq();
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error = (uobj->pgops->pgo_put)(uobj, p->offset,
|
|
p->offset + PAGE_SIZE,
|
|
PGO_CLEANIT|PGO_FREE);
|
|
uvm_lock_pageq();
|
|
if (nextpg &&
|
|
(nextpg->flags & PQ_INACTIVE) == 0) {
|
|
nextpg = TAILQ_FIRST(pglst);
|
|
}
|
|
continue;
|
|
}
|
|
|
|
/*
|
|
* the page is swap-backed. remove all the permissions
|
|
* from the page so we can sync the modified info
|
|
* without any race conditions. if the page is clean
|
|
* we can free it now and continue.
|
|
*/
|
|
|
|
pmap_page_protect(p, VM_PROT_NONE);
|
|
if ((p->flags & PG_CLEAN) && pmap_clear_modify(p)) {
|
|
p->flags &= ~(PG_CLEAN);
|
|
}
|
|
if (p->flags & PG_CLEAN) {
|
|
uvm_pagefree(p);
|
|
uvmexp.pdfreed++;
|
|
|
|
/*
|
|
* for anons, we need to remove the page
|
|
* from the anon ourselves. for aobjs,
|
|
* pagefree did that for us.
|
|
*/
|
|
|
|
if (anon) {
|
|
KASSERT(anon->an_swslot != 0);
|
|
anon->u.an_page = NULL;
|
|
}
|
|
simple_unlock(slock);
|
|
continue;
|
|
}
|
|
|
|
/*
|
|
* this page is dirty, skip it if we'll have met our
|
|
* free target when all the current pageouts complete.
|
|
*/
|
|
|
|
if (uvmexp.free + uvmexp.paging >
|
|
uvmexp.freetarg << 2) {
|
|
simple_unlock(slock);
|
|
continue;
|
|
}
|
|
|
|
/*
|
|
* free any swap space allocated to the page since
|
|
* we'll have to write it again with its new data.
|
|
*/
|
|
|
|
if ((p->pqflags & PQ_ANON) && anon->an_swslot) {
|
|
uvm_swap_free(anon->an_swslot, 1);
|
|
anon->an_swslot = 0;
|
|
} else if (p->pqflags & PQ_AOBJ) {
|
|
uao_dropswap(uobj, p->offset >> PAGE_SHIFT);
|
|
}
|
|
|
|
/*
|
|
* if all pages in swap are only in swap,
|
|
* the swap space is full and we can't page out
|
|
* any more swap-backed pages. reactivate this page
|
|
* so that we eventually cycle all pages through
|
|
* the inactive queue.
|
|
*/
|
|
|
|
KASSERT(uvmexp.swpgonly <= uvmexp.swpages);
|
|
if (uvmexp.swpgonly == uvmexp.swpages) {
|
|
dirtyreacts++;
|
|
uvm_pageactivate(p);
|
|
simple_unlock(slock);
|
|
continue;
|
|
}
|
|
|
|
/*
|
|
* start new swap pageout cluster (if necessary).
|
|
*/
|
|
|
|
if (swslot == 0) {
|
|
swnpages = MAXBSIZE >> PAGE_SHIFT;
|
|
swslot = uvm_swap_alloc(&swnpages, TRUE);
|
|
if (swslot == 0) {
|
|
simple_unlock(slock);
|
|
continue;
|
|
}
|
|
swcpages = 0;
|
|
}
|
|
|
|
/*
|
|
* at this point, we're definitely going reuse this
|
|
* page. mark the page busy and delayed-free.
|
|
* we should remove the page from the page queues
|
|
* so we don't ever look at it again.
|
|
* adjust counters and such.
|
|
*/
|
|
|
|
p->flags |= PG_BUSY;
|
|
UVM_PAGE_OWN(p, "scan_inactive");
|
|
|
|
p->flags |= PG_PAGEOUT;
|
|
uvmexp.paging++;
|
|
uvm_pagedequeue(p);
|
|
|
|
uvmexp.pgswapout++;
|
|
|
|
/*
|
|
* add the new page to the cluster.
|
|
*/
|
|
|
|
if (anon) {
|
|
anon->an_swslot = swslot + swcpages;
|
|
simple_unlock(slock);
|
|
} else {
|
|
result = uao_set_swslot(uobj,
|
|
p->offset >> PAGE_SHIFT, swslot + swcpages);
|
|
if (result == -1) {
|
|
p->flags &= ~(PG_BUSY|PG_PAGEOUT);
|
|
UVM_PAGE_OWN(p, NULL);
|
|
uvmexp.paging--;
|
|
uvm_pageactivate(p);
|
|
simple_unlock(slock);
|
|
continue;
|
|
}
|
|
simple_unlock(slock);
|
|
}
|
|
swpps[swcpages] = p;
|
|
swcpages++;
|
|
|
|
/*
|
|
* if the cluster isn't full, look for more pages
|
|
* before starting the i/o.
|
|
*/
|
|
|
|
if (swcpages < swnpages) {
|
|
continue;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* if this is the final pageout we could have a few
|
|
* unused swap blocks. if so, free them now.
|
|
*/
|
|
|
|
if (swcpages < swnpages) {
|
|
uvm_swap_free(swslot + swcpages, (swnpages - swcpages));
|
|
}
|
|
|
|
/*
|
|
* now start the pageout.
|
|
*/
|
|
|
|
uvm_unlock_pageq();
|
|
uvmexp.pdpageouts++;
|
|
error = uvm_swap_put(swslot, swpps, swcpages, 0);
|
|
KASSERT(error == 0);
|
|
uvm_lock_pageq();
|
|
|
|
/*
|
|
* zero swslot to indicate that we are
|
|
* no longer building a swap-backed cluster.
|
|
*/
|
|
|
|
swslot = 0;
|
|
|
|
/*
|
|
* the pageout is in progress. bump counters and set up
|
|
* for the next loop.
|
|
*/
|
|
|
|
uvmexp.pdpending++;
|
|
if (nextpg && (nextpg->pqflags & PQ_INACTIVE) == 0) {
|
|
nextpg = TAILQ_FIRST(pglst);
|
|
}
|
|
}
|
|
return (error);
|
|
}
|
|
|
|
/*
|
|
* uvmpd_scan: scan the page queues and attempt to meet our targets.
|
|
*
|
|
* => called with pageq's locked
|
|
*/
|
|
|
|
void
|
|
uvmpd_scan(void)
|
|
{
|
|
int inactive_shortage, swap_shortage, pages_freed;
|
|
struct vm_page *p, *nextpg;
|
|
struct uvm_object *uobj;
|
|
struct vm_anon *anon;
|
|
boolean_t got_it;
|
|
UVMHIST_FUNC("uvmpd_scan"); UVMHIST_CALLED(pdhist);
|
|
|
|
uvmexp.pdrevs++;
|
|
uobj = NULL;
|
|
anon = NULL;
|
|
|
|
#ifndef __SWAP_BROKEN
|
|
|
|
/*
|
|
* swap out some processes if we are below our free target.
|
|
* we need to unlock the page queues for this.
|
|
*/
|
|
|
|
if (uvmexp.free < uvmexp.freetarg && uvmexp.nswapdev != 0) {
|
|
uvmexp.pdswout++;
|
|
UVMHIST_LOG(pdhist," free %d < target %d: swapout",
|
|
uvmexp.free, uvmexp.freetarg, 0, 0);
|
|
uvm_unlock_pageq();
|
|
uvm_swapout_threads();
|
|
uvm_lock_pageq();
|
|
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
* now we want to work on meeting our targets. first we work on our
|
|
* free target by converting inactive pages into free pages. then
|
|
* we work on meeting our inactive target by converting active pages
|
|
* to inactive ones.
|
|
*/
|
|
|
|
UVMHIST_LOG(pdhist, " starting 'free' loop",0,0,0,0);
|
|
|
|
/*
|
|
* alternate starting queue between swap and object based on the
|
|
* low bit of uvmexp.pdrevs (which we bump by one each call).
|
|
*/
|
|
|
|
got_it = FALSE;
|
|
pages_freed = uvmexp.pdfreed;
|
|
(void) uvmpd_scan_inactive(&uvm.page_inactive);
|
|
pages_freed = uvmexp.pdfreed - pages_freed;
|
|
|
|
/*
|
|
* we have done the scan to get free pages. now we work on meeting
|
|
* our inactive target.
|
|
*/
|
|
|
|
inactive_shortage = uvmexp.inactarg - uvmexp.inactive;
|
|
|
|
/*
|
|
* detect if we're not going to be able to page anything out
|
|
* until we free some swap resources from active pages.
|
|
*/
|
|
|
|
swap_shortage = 0;
|
|
if (uvmexp.free < uvmexp.freetarg &&
|
|
uvmexp.swpginuse == uvmexp.swpages &&
|
|
uvmexp.swpgonly < uvmexp.swpages &&
|
|
pages_freed == 0) {
|
|
swap_shortage = uvmexp.freetarg - uvmexp.free;
|
|
}
|
|
|
|
UVMHIST_LOG(pdhist, " loop 2: inactive_shortage=%d swap_shortage=%d",
|
|
inactive_shortage, swap_shortage,0,0);
|
|
for (p = TAILQ_FIRST(&uvm.page_active);
|
|
p != NULL && (inactive_shortage > 0 || swap_shortage > 0);
|
|
p = nextpg) {
|
|
nextpg = TAILQ_NEXT(p, pageq);
|
|
if (p->flags & PG_BUSY) {
|
|
continue;
|
|
}
|
|
|
|
/*
|
|
* lock the page's owner.
|
|
*/
|
|
/* is page anon owned or ownerless? */
|
|
if ((p->pqflags & PQ_ANON) || p->uobject == NULL) {
|
|
anon = p->uanon;
|
|
KASSERT(anon != NULL);
|
|
if (!simple_lock_try(&anon->an_lock)) {
|
|
continue;
|
|
}
|
|
|
|
/* take over the page? */
|
|
if ((p->pqflags & PQ_ANON) == 0) {
|
|
KASSERT(p->loan_count > 0);
|
|
p->loan_count--;
|
|
p->pqflags |= PQ_ANON;
|
|
}
|
|
} else {
|
|
uobj = p->uobject;
|
|
if (!simple_lock_try(&uobj->vmobjlock)) {
|
|
continue;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* skip this page if it's busy.
|
|
*/
|
|
|
|
if ((p->flags & PG_BUSY) != 0) {
|
|
if (p->pqflags & PQ_ANON)
|
|
simple_unlock(&anon->an_lock);
|
|
else
|
|
simple_unlock(&uobj->vmobjlock);
|
|
continue;
|
|
}
|
|
|
|
/*
|
|
* if there's a shortage of swap, free any swap allocated
|
|
* to this page so that other pages can be paged out.
|
|
*/
|
|
|
|
if (swap_shortage > 0) {
|
|
if ((p->pqflags & PQ_ANON) && anon->an_swslot) {
|
|
uvm_swap_free(anon->an_swslot, 1);
|
|
anon->an_swslot = 0;
|
|
p->flags &= ~PG_CLEAN;
|
|
swap_shortage--;
|
|
} else if (p->pqflags & PQ_AOBJ) {
|
|
int slot = uao_set_swslot(uobj,
|
|
p->offset >> PAGE_SHIFT, 0);
|
|
if (slot) {
|
|
uvm_swap_free(slot, 1);
|
|
p->flags &= ~PG_CLEAN;
|
|
swap_shortage--;
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* if there's a shortage of inactive pages, deactivate.
|
|
*/
|
|
|
|
if (inactive_shortage > 0) {
|
|
/* no need to check wire_count as pg is "active" */
|
|
uvm_pagedeactivate(p);
|
|
uvmexp.pddeact++;
|
|
inactive_shortage--;
|
|
}
|
|
|
|
/*
|
|
* we're done with this page.
|
|
*/
|
|
|
|
if (p->pqflags & PQ_ANON)
|
|
simple_unlock(&anon->an_lock);
|
|
else
|
|
simple_unlock(&uobj->vmobjlock);
|
|
}
|
|
}
|