403 lines
13 KiB
C
403 lines
13 KiB
C
/* $NetBSD: uvm_page.h,v 1.80 2015/03/23 07:59:12 riastradh 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. 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_page.h 7.3 (Berkeley) 4/21/91
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* from: Id: uvm_page.h,v 1.1.2.6 1998/02/04 02:31:42 chuck 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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#ifndef _UVM_UVM_PAGE_H_
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#define _UVM_UVM_PAGE_H_
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#include <uvm/uvm_extern.h>
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#include <uvm/uvm_pglist.h>
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#include <sys/rbtree.h>
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/*
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* Management of resident (logical) pages.
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*
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* Each resident page has a vm_page structure, indexed by page number.
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* There are several lists in the structure:
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*
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* - A red-black tree rooted with the containing object is used to
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* quickly perform object+offset lookups.
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* - A list of all pages for a given object, for a quick deactivation
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* at a time of deallocation.
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* - An ordered list of pages due for pageout.
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*
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* In addition, the structure contains the object and offset to which
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* this page belongs (for pageout) and sundry status bits.
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*
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* Note that the page structure has no lock of its own. The page is
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* generally protected by its owner's lock (UVM object or amap/anon).
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* It should be noted that UVM has to serialize pmap(9) operations on
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* the managed pages, e.g. for pmap_enter() calls. Hence, the lock
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* order is as follows:
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*
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* [vmpage-owner-lock] ->
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* any pmap locks (e.g. PV hash lock)
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*
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* Since the kernel is always self-consistent, no serialization is
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* required for unmanaged mappings, e.g. for pmap_kenter_pa() calls.
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*
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* Field markings and the corresponding locks:
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*
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* f: free page queue lock, uvm_fpageqlock
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* o: page owner (uvm_object::vmobjlock, vm_amap::am_lock, vm_anon::an_lock)
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* p: page queue lock, uvm_pageqlock
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* o,p: o|p for read, o&p for write
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* w: wired page queue or uvm_pglistalloc:
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* => wired page queue: o&p to change, stable from wire to unwire
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* XXX What about concurrent or nested wire?
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* => uvm_pglistalloc: owned by caller
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* ?: locked by pmap or assumed page owner's lock
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*
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* UVM and pmap(9) may use uvm_page_locked_p() to assert whether the
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* page owner's lock is acquired.
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*
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* A page can have one of four identities:
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*
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* o free
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* => pageq.list is entry on global free page queue
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* => listq.list is entry on per-CPU free page queue
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* => uanon is unused (or (void *)0xdeadbeef for DEBUG)
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* => uobject is unused (or (void *)0xdeadbeef for DEBUG)
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* => PQ_FREE is set in pqflags
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* o owned by a uvm_object
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* => pageq.queue is entry on wired page queue, if any
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* => listq.queue is entry on list of pages in object
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* => uanon is NULL or the vm_anon to which it has been O->A loaned
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* => uobject is owner
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* o owned by a vm_anon
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* => pageq is unused (XXX correct?)
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* => listq is unused (XXX correct?)
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* => uanon is owner
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* => uobject is NULL
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* => PQ_ANON is set in pqflags
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* o allocated by uvm_pglistalloc
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* => pageq.queue is entry on resulting pglist, owned by caller
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* => listq is unused (XXX correct?)
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* => uanon is unused
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* => uobject is unused
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*
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* The following transitions are allowed:
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*
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* - uvm_pagealloc: free -> owned by a uvm_object/vm_anon
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* - uvm_pagefree: owned by a uvm_object/vm_anon -> free
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* - uvm_pglistalloc: free -> allocated by uvm_pglistalloc
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* - uvm_pglistfree: allocated by uvm_pglistalloc -> free
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*/
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struct vm_page {
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struct rb_node rb_node; /* o: tree of pages in obj */
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union {
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TAILQ_ENTRY(vm_page) queue; /* w: wired page queue
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* or uvm_pglistalloc output */
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LIST_ENTRY(vm_page) list; /* f: global free page queue */
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} pageq;
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union {
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TAILQ_ENTRY(vm_page) queue; /* o: pages in same object */
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LIST_ENTRY(vm_page) list; /* f: CPU free page queue */
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} listq;
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struct vm_anon *uanon; /* o,p: anon */
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struct uvm_object *uobject; /* o,p: object */
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voff_t offset; /* o,p: offset into object */
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uint16_t flags; /* o: object flags */
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uint16_t loan_count; /* o,p: num. active loans */
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uint16_t wire_count; /* p: wired down map refs */
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uint16_t pqflags; /* p: page queue flags */
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paddr_t phys_addr; /* physical address of page */
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#ifdef __HAVE_VM_PAGE_MD
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struct vm_page_md mdpage; /* ?: pmap-specific data */
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#endif
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#if defined(UVM_PAGE_TRKOWN)
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/* debugging fields to track page ownership */
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pid_t owner; /* proc that set PG_BUSY */
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lwpid_t lowner; /* lwp that set PG_BUSY */
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const char *owner_tag; /* why it was set busy */
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#endif
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};
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/*
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* Overview of UVM page flags.
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*
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* Locking notes:
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*
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* PG_, struct vm_page::flags => locked by owner
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* PQ_, struct vm_page::pqflags => locked by uvm_pageqlock
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* PQ_FREE => additionally locked by uvm_fpageqlock
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*
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* Flag descriptions:
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*
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* PG_BUSY:
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* Page is long-term locked, usually because of I/O (transfer from the
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* page memory to the backing store) is in progress. LWP attempting
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* to access the page shall set PG_WANTED and wait.
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*
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* PG_WANTED:
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* Indicates that the page, which is currently PG_BUSY, is wanted by
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* some other LWP. The page owner (i.e. LWP which set PG_BUSY) is
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* responsible to clear both flags and wake up any waiters once it has
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* released the long-term lock (PG_BUSY).
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*
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* PG_RELEASED:
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* Indicates that the page, which is currently PG_BUSY, should be freed
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* after the release of long-term lock. It is responsibility of the
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* owning LWP (i.e. which set PG_BUSY) to do it.
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*
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* PG_CLEAN:
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* Page has not been modified since it was loaded from the backing
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* store. If this flag is not set, page is considered "dirty".
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* XXX: Currently it means that the page *might* be clean; will be
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* fixed with yamt-pagecache merge.
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*
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* PG_FAKE:
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* Page has been allocated, but not yet initialised. The flag is used
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* to avoid overwriting of valid data, e.g. to prevent read from the
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* backing store when in-core data is newer.
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*
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* PG_TABLED:
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* Indicates that the page is currently in the object's offset queue,
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* and that it should be removed from it once the page is freed. Used
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* diagnostic purposes.
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*
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* PG_PAGEOUT:
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* Indicates that the page is being paged-out in preparation for
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* being freed.
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*
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* PG_RDONLY:
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* Indicates that the page must be mapped read-only.
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*
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* PG_ZERO:
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* Indicates that the page has been pre-zeroed. This flag is only
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* set when the page is not in the queues and is cleared when the
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* page is placed on the free list.
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*
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* PG_MARKER:
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* Dummy marker page.
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*/
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#define PG_BUSY 0x0001
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#define PG_WANTED 0x0002
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#define PG_TABLED 0x0004
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#define PG_CLEAN 0x0008
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#define PG_PAGEOUT 0x0010
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#define PG_RELEASED 0x0020
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#define PG_FAKE 0x0040
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#define PG_RDONLY 0x0080
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#define PG_ZERO 0x0100
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#define PG_MARKER 0x0200
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#define PG_PAGER1 0x1000 /* pager-specific flag */
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#define UVM_PGFLAGBITS \
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"\20\1BUSY\2WANTED\3TABLED\4CLEAN\5PAGEOUT\6RELEASED\7FAKE\10RDONLY" \
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"\11ZERO\12MARKER\15PAGER1"
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#define PQ_FREE 0x0001 /* page is on free list */
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#define PQ_ANON 0x0002 /* page is part of an anon, rather
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than an uvm_object */
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#define PQ_AOBJ 0x0004 /* page is part of an anonymous
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uvm_object */
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#define PQ_SWAPBACKED (PQ_ANON|PQ_AOBJ)
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#define PQ_READAHEAD 0x0008 /* read-ahead but has not been "hit" yet */
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#define PQ_PRIVATE1 0x0100
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#define PQ_PRIVATE2 0x0200
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#define PQ_PRIVATE3 0x0400
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#define PQ_PRIVATE4 0x0800
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#define PQ_PRIVATE5 0x1000
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#define PQ_PRIVATE6 0x2000
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#define PQ_PRIVATE7 0x4000
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#define PQ_PRIVATE8 0x8000
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#define UVM_PQFLAGBITS \
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"\20\1FREE\2ANON\3AOBJ\4READAHEAD" \
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"\11PRIVATE1\12PRIVATE2\13PRIVATE3\14PRIVATE4" \
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"\15PRIVATE5\16PRIVATE6\17PRIVATE7\20PRIVATE8"
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/*
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* physical memory layout structure
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*
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* MD vmparam.h must #define:
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* VM_PHYSEG_MAX = max number of physical memory segments we support
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* (if this is "1" then we revert to a "contig" case)
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* VM_PHYSSEG_STRAT: memory sort/search options (for VM_PHYSEG_MAX > 1)
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* - VM_PSTRAT_RANDOM: linear search (random order)
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* - VM_PSTRAT_BSEARCH: binary search (sorted by address)
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* - VM_PSTRAT_BIGFIRST: linear search (sorted by largest segment first)
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* - others?
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* XXXCDC: eventually we should purge all left-over global variables...
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*/
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#define VM_PSTRAT_RANDOM 1
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#define VM_PSTRAT_BSEARCH 2
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#define VM_PSTRAT_BIGFIRST 3
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/*
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* vm_physseg: describes one segment of physical memory
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*/
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struct vm_physseg {
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paddr_t start; /* PF# of first page in segment */
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paddr_t end; /* (PF# of last page in segment) + 1 */
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paddr_t avail_start; /* PF# of first free page in segment */
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paddr_t avail_end; /* (PF# of last free page in segment) +1 */
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struct vm_page *pgs; /* vm_page structures (from start) */
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struct vm_page *lastpg; /* vm_page structure for end */
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int free_list; /* which free list they belong on */
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u_int start_hint; /* start looking for free pages here */
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/* protected by uvm_fpageqlock */
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#ifdef __HAVE_PMAP_PHYSSEG
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struct pmap_physseg pmseg; /* pmap specific (MD) data */
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#endif
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};
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#ifdef _KERNEL
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/*
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* globals
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*/
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extern bool vm_page_zero_enable;
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/*
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* physical memory config is stored in vm_physmem.
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*/
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#define VM_PHYSMEM_PTR(i) (&vm_physmem[i])
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#if VM_PHYSSEG_MAX == 1
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#define VM_PHYSMEM_PTR_SWAP(i, j) /* impossible */
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#else
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#define VM_PHYSMEM_PTR_SWAP(i, j) \
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do { vm_physmem[(i)] = vm_physmem[(j)]; } while (0)
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#endif
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extern struct vm_physseg vm_physmem[VM_PHYSSEG_MAX];
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extern int vm_nphysseg;
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/*
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* prototypes: the following prototypes define the interface to pages
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*/
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void uvm_page_init(vaddr_t *, vaddr_t *);
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#if defined(UVM_PAGE_TRKOWN)
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void uvm_page_own(struct vm_page *, const char *);
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#endif
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#if !defined(PMAP_STEAL_MEMORY)
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bool uvm_page_physget(paddr_t *);
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#endif
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void uvm_page_recolor(int);
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void uvm_pageidlezero(void);
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void uvm_pageactivate(struct vm_page *);
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vaddr_t uvm_pageboot_alloc(vsize_t);
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void uvm_pagecopy(struct vm_page *, struct vm_page *);
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void uvm_pagedeactivate(struct vm_page *);
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void uvm_pagedequeue(struct vm_page *);
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void uvm_pageenqueue(struct vm_page *);
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void uvm_pagefree(struct vm_page *);
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void uvm_page_unbusy(struct vm_page **, int);
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struct vm_page *uvm_pagelookup(struct uvm_object *, voff_t);
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void uvm_pageunwire(struct vm_page *);
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void uvm_pagewire(struct vm_page *);
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void uvm_pagezero(struct vm_page *);
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bool uvm_pageismanaged(paddr_t);
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bool uvm_page_locked_p(struct vm_page *);
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int uvm_page_lookup_freelist(struct vm_page *);
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int vm_physseg_find(paddr_t, int *);
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struct vm_page *uvm_phys_to_vm_page(paddr_t);
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paddr_t uvm_vm_page_to_phys(const struct vm_page *);
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/*
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* macros
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*/
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#define UVM_PAGE_TREE_PENALTY 4 /* XXX: a guess */
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#define VM_PAGE_TO_PHYS(entry) uvm_vm_page_to_phys(entry)
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#ifdef __HAVE_VM_PAGE_MD
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#define VM_PAGE_TO_MD(pg) (&(pg)->mdpage)
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#endif
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/*
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* Compute the page color bucket for a given page.
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*/
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#define VM_PGCOLOR_BUCKET(pg) \
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(atop(VM_PAGE_TO_PHYS((pg))) & uvmexp.colormask)
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#define PHYS_TO_VM_PAGE(pa) uvm_phys_to_vm_page(pa)
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#define VM_PAGE_IS_FREE(entry) ((entry)->pqflags & PQ_FREE)
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#define VM_FREE_PAGE_TO_CPU(pg) ((struct uvm_cpu *)((uintptr_t)pg->offset))
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#ifdef DEBUG
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void uvm_pagezerocheck(struct vm_page *);
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#endif /* DEBUG */
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#endif /* _KERNEL */
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#endif /* _UVM_UVM_PAGE_H_ */
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