minix/sys/uvm/uvm_page.h

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/* $NetBSD: uvm_page.h,v 1.75 2012/05/05 20:45:35 rmind Exp $ */
/*
* Copyright (c) 1997 Charles D. Cranor and Washington University.
* Copyright (c) 1991, 1993, The Regents of the University of California.
*
* All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* The Mach Operating System project at Carnegie-Mellon University.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)vm_page.h 7.3 (Berkeley) 4/21/91
* from: Id: uvm_page.h,v 1.1.2.6 1998/02/04 02:31:42 chuck Exp
*
*
* Copyright (c) 1987, 1990 Carnegie-Mellon University.
* All rights reserved.
*
* Permission to use, copy, modify and distribute this software and
* its documentation is hereby granted, provided that both the copyright
* notice and this permission notice appear in all copies of the
* software, derivative works or modified versions, and any portions
* thereof, and that both notices appear in supporting documentation.
*
* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
* FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
*
* Carnegie Mellon requests users of this software to return to
*
* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
* School of Computer Science
* Carnegie Mellon University
* Pittsburgh PA 15213-3890
*
* any improvements or extensions that they make and grant Carnegie the
* rights to redistribute these changes.
*/
#ifndef _UVM_UVM_PAGE_H_
#define _UVM_UVM_PAGE_H_
#include <uvm/uvm_extern.h>
#include <uvm/uvm_pglist.h>
#include <sys/rbtree.h>
/*
* Management of resident (logical) pages.
*
* Each resident page has a vm_page structure, indexed by page number.
* There are several lists in the structure:
*
* - A red-black tree rooted with the containing object is used to
* quickly perform object+offset lookups.
* - A list of all pages for a given object, for a quick deactivation
* at a time of deallocation.
* - An ordered list of pages due for pageout.
*
* In addition, the structure contains the object and offset to which
* this page belongs (for pageout) and sundry status bits.
*
* Note that the page structure has no lock of its own. The page is
* generally protected by its owner's lock (UVM object or amap/anon).
* It should be noted that UVM has to serialize pmap(9) operations on
* the managed pages, e.g. for pmap_enter() calls. Hence, the lock
* order is as follows:
*
* [vmpage-owner-lock] ->
* any pmap locks (e.g. PV hash lock)
*
* Since the kernel is always self-consistent, no serialization is
* required for unmanaged mappings, e.g. for pmap_kenter_pa() calls.
*
* Field markings and the corresponding locks:
*
* o: page owner's lock (UVM object or amap/anon)
* p: lock on the page queues
* o|p: either lock can be acquired
* o&p: both locks are required
* ?: locked by pmap or assumed page owner's lock
*
* UVM and pmap(9) may use uvm_page_locked_p() to assert whether the
* page owner's lock is acquired.
*/
struct vm_page {
struct rb_node rb_node; /* o: tree of pages in obj */
union {
TAILQ_ENTRY(vm_page) queue;
LIST_ENTRY(vm_page) list;
} pageq; /* p: queue info for FIFO
* queue or free list */
union {
TAILQ_ENTRY(vm_page) queue;
LIST_ENTRY(vm_page) list;
} listq; /* o: pages in same object */
struct vm_anon *uanon; /* o,p: anon */
struct uvm_object *uobject; /* o,p: object */
voff_t offset; /* o,p: offset into object */
uint16_t flags; /* o: object flags */
uint16_t loan_count; /* number of active loans
* o|p: for reading
* o&p: for modification */
uint16_t wire_count; /* p: wired down map refs */
uint16_t pqflags; /* p: page queue flags */
paddr_t phys_addr; /* physical address of page */
#ifdef __HAVE_VM_PAGE_MD
struct vm_page_md mdpage; /* ?: pmap-specific data */
#endif
#if defined(UVM_PAGE_TRKOWN)
/* debugging fields to track page ownership */
pid_t owner; /* proc that set PG_BUSY */
lwpid_t lowner; /* lwp that set PG_BUSY */
const char *owner_tag; /* why it was set busy */
#endif
};
/*
* Overview of UVM page flags.
*
* Locking notes:
*
* PG_, struct vm_page::flags => locked by the owner
* PQ_, struct vm_page::pqflags => locked by the page-queue lock
* PQ_FREE => additionally locked by free-queue lock
*
* Flag descriptions:
*
* PG_BUSY:
* Page is long-term locked, usually because of I/O (transfer from the
* page memory to the backing store) is in progress. LWP attempting
* to access the page shall set PG_WANTED and wait.
*
* PG_WANTED:
* Indicates that the page, which is currently PG_BUSY, is wanted by
* some other LWP. The page owner (i.e. LWP which set PG_BUSY) is
* responsible to clear both flags and wake up any waiters once it has
* released the long-term lock (PG_BUSY).
*
* PG_RELEASED:
* Indicates that the page, which is currently PG_BUSY, should be freed
* after the release of long-term lock. It is responsibility of the
* owning LWP (i.e. which set PG_BUSY) to do it.
*
* PG_CLEAN:
* Page has not been modified since it was loaded from the backing
* store. If this flag is not set, page is considered "dirty".
* XXX: Currently it means that the page *might* be clean; will be
* fixed with yamt-pagecache merge.
*
* PG_FAKE:
* Page has been allocated, but not yet initialised. The flag is used
* to avoid overwriting of valid data, e.g. to prevent read from the
* backing store when in-core data is newer.
*
* PG_TABLED:
* Indicates that the page is currently in the object's offset queue,
* and that it should be removed from it once the page is freed. Used
* diagnostic purposes.
*
* PG_PAGEOUT:
* Indicates that the page is being paged-out in preparation for
* being freed.
*
* PG_RDONLY:
* Indicates that the page must be mapped read-only.
*
* PG_ZERO:
* Indicates that the page has been pre-zeroed. This flag is only
* set when the page is not in the queues and is cleared when the
* page is placed on the free list.
*
* PG_MARKER:
* Dummy marker page.
*/
#define PG_BUSY 0x0001
#define PG_WANTED 0x0002
#define PG_TABLED 0x0004
#define PG_CLEAN 0x0008
#define PG_PAGEOUT 0x0010
#define PG_RELEASED 0x0020
#define PG_FAKE 0x0040
#define PG_RDONLY 0x0080
#define PG_ZERO 0x0100
#define PG_MARKER 0x0200
#define PG_PAGER1 0x1000 /* pager-specific flag */
#define UVM_PGFLAGBITS \
"\20\1BUSY\2WANTED\3TABLED\4CLEAN\5PAGEOUT\6RELEASED\7FAKE\10RDONLY" \
"\11ZERO\12MARKER\15PAGER1"
#define PQ_FREE 0x0001 /* page is on free list */
#define PQ_ANON 0x0002 /* page is part of an anon, rather
than an uvm_object */
#define PQ_AOBJ 0x0004 /* page is part of an anonymous
uvm_object */
#define PQ_SWAPBACKED (PQ_ANON|PQ_AOBJ)
#define PQ_READAHEAD 0x0008 /* read-ahead but has not been "hit" yet */
#define PQ_PRIVATE1 0x0100
#define PQ_PRIVATE2 0x0200
#define PQ_PRIVATE3 0x0400
#define PQ_PRIVATE4 0x0800
#define PQ_PRIVATE5 0x1000
#define PQ_PRIVATE6 0x2000
#define PQ_PRIVATE7 0x4000
#define PQ_PRIVATE8 0x8000
#define UVM_PQFLAGBITS \
"\20\1FREE\2ANON\3AOBJ\4READAHEAD" \
"\11PRIVATE1\12PRIVATE2\13PRIVATE3\14PRIVATE4" \
"\15PRIVATE5\16PRIVATE6\17PRIVATE7\20PRIVATE8"
/*
* physical memory layout structure
*
* MD vmparam.h must #define:
* VM_PHYSEG_MAX = max number of physical memory segments we support
* (if this is "1" then we revert to a "contig" case)
* VM_PHYSSEG_STRAT: memory sort/search options (for VM_PHYSEG_MAX > 1)
* - VM_PSTRAT_RANDOM: linear search (random order)
* - VM_PSTRAT_BSEARCH: binary search (sorted by address)
* - VM_PSTRAT_BIGFIRST: linear search (sorted by largest segment first)
* - others?
* XXXCDC: eventually we should purge all left-over global variables...
*/
#define VM_PSTRAT_RANDOM 1
#define VM_PSTRAT_BSEARCH 2
#define VM_PSTRAT_BIGFIRST 3
/*
* vm_physseg: describes one segment of physical memory
*/
struct vm_physseg {
paddr_t start; /* PF# of first page in segment */
paddr_t end; /* (PF# of last page in segment) + 1 */
paddr_t avail_start; /* PF# of first free page in segment */
paddr_t avail_end; /* (PF# of last free page in segment) +1 */
struct vm_page *pgs; /* vm_page structures (from start) */
struct vm_page *lastpg; /* vm_page structure for end */
int free_list; /* which free list they belong on */
u_int start_hint; /* start looking for free pages here */
/* protected by uvm_fpageqlock */
#ifdef __HAVE_PMAP_PHYSSEG
struct pmap_physseg pmseg; /* pmap specific (MD) data */
#endif
};
#ifdef _KERNEL
/*
* globals
*/
extern bool vm_page_zero_enable;
/*
* physical memory config is stored in vm_physmem.
*/
#define VM_PHYSMEM_PTR(i) (&vm_physmem[i])
#define VM_PHYSMEM_PTR_SWAP(i, j) \
do { vm_physmem[(i)] = vm_physmem[(j)]; } while (0)
extern struct vm_physseg vm_physmem[VM_PHYSSEG_MAX];
extern int vm_nphysseg;
/*
* prototypes: the following prototypes define the interface to pages
*/
void uvm_page_init(vaddr_t *, vaddr_t *);
#if defined(UVM_PAGE_TRKOWN)
void uvm_page_own(struct vm_page *, const char *);
#endif
#if !defined(PMAP_STEAL_MEMORY)
bool uvm_page_physget(paddr_t *);
#endif
void uvm_page_recolor(int);
void uvm_pageidlezero(void);
void uvm_pageactivate(struct vm_page *);
vaddr_t uvm_pageboot_alloc(vsize_t);
void uvm_pagecopy(struct vm_page *, struct vm_page *);
void uvm_pagedeactivate(struct vm_page *);
void uvm_pagedequeue(struct vm_page *);
void uvm_pageenqueue(struct vm_page *);
void uvm_pagefree(struct vm_page *);
void uvm_page_unbusy(struct vm_page **, int);
struct vm_page *uvm_pagelookup(struct uvm_object *, voff_t);
void uvm_pageunwire(struct vm_page *);
void uvm_pagewire(struct vm_page *);
void uvm_pagezero(struct vm_page *);
bool uvm_pageismanaged(paddr_t);
bool uvm_page_locked_p(struct vm_page *);
int uvm_page_lookup_freelist(struct vm_page *);
int vm_physseg_find(paddr_t, int *);
struct vm_page *uvm_phys_to_vm_page(paddr_t);
paddr_t uvm_vm_page_to_phys(const struct vm_page *);
/*
* macros
*/
#define UVM_PAGE_TREE_PENALTY 4 /* XXX: a guess */
#define VM_PAGE_TO_PHYS(entry) uvm_vm_page_to_phys(entry)
#ifdef __HAVE_VM_PAGE_MD
#define VM_PAGE_TO_MD(pg) (&(pg)->mdpage)
#endif
/*
* Compute the page color bucket for a given page.
*/
#define VM_PGCOLOR_BUCKET(pg) \
(atop(VM_PAGE_TO_PHYS((pg))) & uvmexp.colormask)
#define PHYS_TO_VM_PAGE(pa) uvm_phys_to_vm_page(pa)
#define VM_PAGE_IS_FREE(entry) ((entry)->pqflags & PQ_FREE)
#define VM_FREE_PAGE_TO_CPU(pg) ((struct uvm_cpu *)((uintptr_t)pg->offset))
#ifdef DEBUG
void uvm_pagezerocheck(struct vm_page *);
#endif /* DEBUG */
#endif /* _KERNEL */
#endif /* _UVM_UVM_PAGE_H_ */