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freebsd-src/sys/vm/vm_page.h
John Dyson 8f9110f6a1 This mega-commit is meant to fix numerous interrelated problems. There 
has been some bitrot and incorrect assumptions in the vfs_bio code.  These
problems have manifest themselves worse on NFS type filesystems, but can
still affect local filesystems under certain circumstances.  Most of
the problems have involved mmap consistancy, and as a side-effect broke
the vfs.ioopt code.  This code might have been committed seperately, but
almost everything is interrelated.

1)	Allow (pmap_object_init_pt) prefaulting of buffer-busy pages that
	are fully valid.
2)	Rather than deactivating erroneously read initial (header) pages in
	kern_exec, we now free them.
3)	Fix the rundown of non-VMIO buffers that are in an inconsistent
	(missing vp) state.
4)	Fix the disassociation of pages from buffers in brelse.  The previous
	code had rotted and was faulty in a couple of important circumstances.
5)	Remove a gratuitious buffer wakeup in vfs_vmio_release.
6)	Remove a crufty and currently unused cluster mechanism for VBLK
	files in vfs_bio_awrite.  When the code is functional, I'll add back
	a cleaner version.
7)	The page busy count wakeups assocated with the buffer cache usage were
	incorrectly cleaned up in a previous commit by me.  Revert to the
	original, correct version, but with a cleaner implementation.
8)	The cluster read code now tries to keep data associated with buffers
	more aggressively (without breaking the heuristics) when it is presumed
	that the read data (buffers) will be soon needed.
9)	Change to filesystem lockmgr locks so that they use LK_NOPAUSE.  The
	delay loop waiting is not useful for filesystem locks, due to the
	length of the time intervals.
10)	Correct and clean-up spec_getpages.
11)	Implement a fully functional nfs_getpages, nfs_putpages.
12)	Fix nfs_write so that modifications are coherent with the NFS data on
	the server disk (at least as well as NFS seems to allow.)
13)	Properly support MS_INVALIDATE on NFS.
14)	Properly pass down MS_INVALIDATE to lower levels of the VM code from
	vm_map_clean.
15)	Better support the notion of pages being busy but valid, so that
	fewer in-transit waits occur.  (use p->busy more for pageouts instead
	of PG_BUSY.)  Since the page is fully valid, it is still usable for
	reads.
16)	It is possible (in error) for cached pages to be busy.  Make the
	page allocation code handle that case correctly.  (It should probably
	be a printf or panic, but I want the system to handle coding errors
	robustly.  I'll probably add a printf.)
17)	Correct the design and usage of vm_page_sleep.  It didn't handle
	consistancy problems very well, so make the design a little less
	lofty.  After vm_page_sleep, if it ever blocked, it is still important
	to relookup the page (if the object generation count changed), and
	verify it's status (always.)
18)	In vm_pageout.c, vm_pageout_clean had rotted, so clean that up.
19)	Push the page busy for writes and VM_PROT_READ into vm_pageout_flush.
20)	Fix vm_pager_put_pages and it's descendents to support an int flag
	instead of a boolean, so that we can pass down the invalidate bit.
1998-03-07 21:37:31 +00:00

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/*
* 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. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. 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.
*
* from: @(#)vm_page.h 8.2 (Berkeley) 12/13/93
*
*
* Copyright (c) 1987, 1990 Carnegie-Mellon University.
* All rights reserved.
*
* Authors: Avadis Tevanian, Jr., Michael Wayne Young
*
* 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.
*
* $Id: vm_page.h,v 1.37 1998/03/01 04:18:26 dyson Exp $
*/
/*
* Resident memory system definitions.
*/
#ifndef _VM_PAGE_
#define _VM_PAGE_
#include <vm/pmap.h>
/*
* Management of resident (logical) pages.
*
* A small structure is kept for each resident
* page, indexed by page number. Each structure
* is an element of several lists:
*
* A hash table bucket used to quickly
* perform object/offset lookups
*
* A list of all pages for a given object,
* so they can be quickly deactivated at
* 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.
*
* Fields in this structure are locked either by the lock on the
* object that the page belongs to (O) or by the lock on the page
* queues (P).
*/
TAILQ_HEAD(pglist, vm_page);
struct vm_page {
TAILQ_ENTRY(vm_page) pageq; /* queue info for FIFO queue or free list (P) */
TAILQ_ENTRY(vm_page) hashq; /* hash table links (O) */
TAILQ_ENTRY(vm_page) listq; /* pages in same object (O) */
vm_object_t object; /* which object am I in (O,P) */
vm_pindex_t pindex; /* offset into object (O,P) */
vm_offset_t phys_addr; /* physical address of page */
u_short queue; /* page queue index */
u_short flags, /* see below */
pc; /* page color */
u_short wire_count; /* wired down maps refs (P) */
short hold_count; /* page hold count */
u_char act_count; /* page usage count */
u_char busy; /* page busy count */
/* NOTE that these must support one bit per DEV_BSIZE in a page!!! */
/* so, on normal X86 kernels, they must be at least 8 bits wide */
u_char valid; /* map of valid DEV_BSIZE chunks */
u_char dirty; /* map of dirty DEV_BSIZE chunks */
};
/*
* Page coloring parameters
*/
/* Each of PQ_FREE, PQ_ZERO and PQ_CACHE have PQ_HASH_SIZE entries */
/* Define one of the following */
#if defined(PQ_LARGECACHE)
#define PQ_PRIME1 31 /* Prime number somewhat less than PQ_HASH_SIZE */
#define PQ_PRIME2 23 /* Prime number somewhat less than PQ_HASH_SIZE */
#define PQ_PRIME3 17 /* Prime number somewhat less than PQ_HASH_SIZE */
#define PQ_L2_SIZE 128 /* A number of colors opt for 512K cache */
#define PQ_L1_SIZE 2 /* Two page L1 cache */
#endif
/*
* Use 'options PQ_NOOPT' to disable page coloring
*/
#if defined(PQ_NOOPT)
#define PQ_PRIME1 1
#define PQ_PRIME2 1
#define PQ_PRIME3 1
#define PQ_L2_SIZE 1
#define PQ_L1_SIZE 1
#endif
#if defined(PQ_NORMALCACHE)
#define PQ_PRIME1 5 /* Prime number somewhat less than PQ_HASH_SIZE */
#define PQ_PRIME2 3 /* Prime number somewhat less than PQ_HASH_SIZE */
#define PQ_PRIME3 11 /* Prime number somewhat less than PQ_HASH_SIZE */
#define PQ_L2_SIZE 16 /* A reasonable number of colors (opt for 64K cache) */
#define PQ_L1_SIZE 2 /* Two page L1 cache */
#endif
#if defined(PQ_MEDIUMCACHE) || !defined(PQ_L2_SIZE)
#define PQ_PRIME1 13 /* Prime number somewhat less than PQ_HASH_SIZE */
#define PQ_PRIME2 7 /* Prime number somewhat less than PQ_HASH_SIZE */
#define PQ_PRIME3 5 /* Prime number somewhat less than PQ_HASH_SIZE */
#define PQ_L2_SIZE 64 /* A number of colors opt for 256K cache */
#define PQ_L1_SIZE 2 /* Two page L1 cache */
#endif
#define PQ_L2_MASK (PQ_L2_SIZE - 1)
#define PQ_NONE 0
#define PQ_FREE 1
#define PQ_ZERO (1 + PQ_L2_SIZE)
#define PQ_INACTIVE (1 + 2*PQ_L2_SIZE)
#define PQ_ACTIVE (2 + 2*PQ_L2_SIZE)
#define PQ_CACHE (3 + 2*PQ_L2_SIZE)
#define PQ_COUNT (3 + 3*PQ_L2_SIZE)
extern struct vpgqueues {
struct pglist *pl;
int *cnt;
int *lcnt;
} vm_page_queues[PQ_COUNT];
/*
* These are the flags defined for vm_page.
*
* Note: PG_FILLED and PG_DIRTY are added for the filesystems.
*/
#define PG_BUSY 0x01 /* page is in transit (O) */
#define PG_WANTED 0x02 /* someone is waiting for page (O) */
#define PG_TABLED 0x04 /* page is in VP table (O) */
#define PG_FICTITIOUS 0x08 /* physical page doesn't exist (O) */
#define PG_WRITEABLE 0x10 /* page is mapped writeable */
#define PG_MAPPED 0x20 /* page is mapped */
#define PG_ZERO 0x40 /* page is zeroed */
#define PG_REFERENCED 0x80 /* page has been referenced */
#define PG_CLEANCHK 0x100 /* page has been checked for cleaning */
/*
* Misc constants.
*/
#define ACT_DECLINE 1
#define ACT_ADVANCE 3
#define ACT_INIT 5
#define ACT_MAX 64
#define PFCLUSTER_BEHIND 3
#define PFCLUSTER_AHEAD 3
#ifdef KERNEL
/*
* Each pageable resident page falls into one of four lists:
*
* free
* Available for allocation now.
*
* The following are all LRU sorted:
*
* cache
* Almost available for allocation. Still in an
* object, but clean and immediately freeable at
* non-interrupt times.
*
* inactive
* Low activity, candidates for reclamation.
* This is the list of pages that should be
* paged out next.
*
* active
* Pages that are "active" i.e. they have been
* recently referenced.
*
* zero
* Pages that are really free and have been pre-zeroed
*
*/
extern struct pglist vm_page_queue_free[PQ_L2_SIZE];/* memory free queue */
extern struct pglist vm_page_queue_zero[PQ_L2_SIZE];/* zeroed memory free queue */
extern struct pglist vm_page_queue_active; /* active memory queue */
extern struct pglist vm_page_queue_inactive; /* inactive memory queue */
extern struct pglist vm_page_queue_cache[PQ_L2_SIZE];/* cache memory queue */
extern int vm_page_zero_count;
extern vm_page_t vm_page_array; /* First resident page in table */
extern long first_page; /* first physical page number */
/* ... represented in vm_page_array */
extern long last_page; /* last physical page number */
/* ... represented in vm_page_array */
/* [INCLUSIVE] */
extern vm_offset_t first_phys_addr; /* physical address for first_page */
extern vm_offset_t last_phys_addr; /* physical address for last_page */
#define VM_PAGE_TO_PHYS(entry) ((entry)->phys_addr)
#define IS_VM_PHYSADDR(pa) \
((pa) >= first_phys_addr && (pa) <= last_phys_addr)
#define PHYS_TO_VM_PAGE(pa) \
(&vm_page_array[atop(pa) - first_page ])
/*
* Functions implemented as macros
*/
#define PAGE_ASSERT_WAIT(m, interruptible) { \
(m)->flags |= PG_WANTED; \
assert_wait((int) (m), (interruptible)); \
}
#define PAGE_WAKEUP(m) { \
(m)->flags &= ~PG_BUSY; \
if (((m)->flags & PG_WANTED) && ((m)->busy == 0)) { \
(m)->flags &= ~PG_WANTED; \
wakeup((m)); \
} \
}
#define PAGE_BWAKEUP(m) { \
(m)->busy--; \
if ((((m)->flags & (PG_WANTED | PG_BUSY)) == PG_WANTED) && \
((m)->busy == 0)) { \
(m)->flags &= ~PG_WANTED; \
wakeup((m)); \
} \
}
#if PAGE_SIZE == 4096
#define VM_PAGE_BITS_ALL 0xff
#endif
#if PAGE_SIZE == 8192
#define VM_PAGE_BITS_ALL 0xffff
#endif
#define VM_ALLOC_NORMAL 0
#define VM_ALLOC_INTERRUPT 1
#define VM_ALLOC_SYSTEM 2
#define VM_ALLOC_ZERO 3
#define VM_ALLOC_RETRY 0x80
void vm_page_activate __P((vm_page_t));
vm_page_t vm_page_alloc __P((vm_object_t, vm_pindex_t, int));
vm_page_t vm_page_grab __P((vm_object_t, vm_pindex_t, int));
void vm_page_cache __P((register vm_page_t));
static __inline void vm_page_copy __P((vm_page_t, vm_page_t));
void vm_page_deactivate __P((vm_page_t));
void vm_page_free __P((vm_page_t));
void vm_page_free_zero __P((vm_page_t));
void vm_page_insert __P((vm_page_t, vm_object_t, vm_pindex_t));
vm_page_t vm_page_lookup __P((vm_object_t, vm_pindex_t));
void vm_page_remove __P((vm_page_t));
void vm_page_rename __P((vm_page_t, vm_object_t, vm_pindex_t));
vm_offset_t vm_page_startup __P((vm_offset_t, vm_offset_t, vm_offset_t));
void vm_page_unwire __P((vm_page_t));
void vm_page_wire __P((vm_page_t));
void vm_page_unqueue __P((vm_page_t));
void vm_page_unqueue_nowakeup __P((vm_page_t));
void vm_page_set_validclean __P((vm_page_t, int, int));
void vm_page_set_invalid __P((vm_page_t, int, int));
static __inline boolean_t vm_page_zero_fill __P((vm_page_t));
int vm_page_is_valid __P((vm_page_t, int, int));
void vm_page_test_dirty __P((vm_page_t));
int vm_page_bits __P((int, int));
vm_page_t vm_page_list_find __P((int, int));
int vm_page_queue_index __P((vm_offset_t, int));
vm_page_t vm_page_select __P((vm_object_t, vm_pindex_t, int));
int vm_page_sleep(vm_page_t m, char *msg, char *busy);
/*
* Keep page from being freed by the page daemon
* much of the same effect as wiring, except much lower
* overhead and should be used only for *very* temporary
* holding ("wiring").
*/
static __inline void
vm_page_hold(vm_page_t mem)
{
mem->hold_count++;
}
#ifdef DIAGNOSTIC
#include <sys/systm.h> /* make GCC shut up */
#endif
static __inline void
vm_page_unhold(vm_page_t mem)
{
#ifdef DIAGNOSTIC
if (--mem->hold_count < 0)
panic("vm_page_unhold: hold count < 0!!!");
#else
--mem->hold_count;
#endif
}
static __inline void
vm_page_protect(vm_page_t mem, int prot)
{
if (prot == VM_PROT_NONE) {
if (mem->flags & (PG_WRITEABLE|PG_MAPPED)) {
pmap_page_protect(VM_PAGE_TO_PHYS(mem), VM_PROT_NONE);
mem->flags &= ~(PG_WRITEABLE|PG_MAPPED);
}
} else if ((prot == VM_PROT_READ) && (mem->flags & PG_WRITEABLE)) {
pmap_page_protect(VM_PAGE_TO_PHYS(mem), VM_PROT_READ);
mem->flags &= ~PG_WRITEABLE;
}
}
/*
* vm_page_zero_fill:
*
* Zero-fill the specified page.
* Written as a standard pagein routine, to
* be used by the zero-fill object.
*/
static __inline boolean_t
vm_page_zero_fill(m)
vm_page_t m;
{
pmap_zero_page(VM_PAGE_TO_PHYS(m));
return (TRUE);
}
/*
* vm_page_copy:
*
* Copy one page to another
*/
static __inline void
vm_page_copy(src_m, dest_m)
vm_page_t src_m;
vm_page_t dest_m;
{
pmap_copy_page(VM_PAGE_TO_PHYS(src_m), VM_PAGE_TO_PHYS(dest_m));
dest_m->valid = VM_PAGE_BITS_ALL;
}
#endif /* KERNEL */
#endif /* !_VM_PAGE_ */
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