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NetBSD/sys/uvm/uvm_page.h

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/* $NetBSD: uvm_page.h,v 1.109 2020/12/20 16:38:26 skrll 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_
#ifdef _KERNEL_OPT
#include "opt_uvm_page_trkown.h"
#endif
#include <sys/rwlock.h>
#include <uvm/uvm_extern.h>
#include <uvm/uvm_pglist.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:
*
* f: free page queue lock, uvm_fpageqlock
* o: page owner (uvm_object::vmobjlock, vm_amap::am_lock, vm_anon::an_lock)
* i: vm_page::interlock
* => flags set and cleared only with o&i held can
* safely be tested for with only o held.
* o,i: o|i for read, o&i for write (depends on context - if could be loaned)
* => see uvm_loan.c
* w: wired page queue or uvm_pglistalloc:
* => wired page queue: o&i to change, stable from wire to unwire
* XXX What about concurrent or nested wire?
* => uvm_pglistalloc: owned by caller
* ?: locked by pmap or assumed page owner's lock
* p: locked by pagedaemon policy module (pdpolicy)
* c: cpu private
* s: stable, does not change
*
* UVM and pmap(9) may use uvm_page_owner_locked_p() to assert whether the
* page owner's lock is acquired.
*
* A page can have one of four identities:
*
* o free
* => pageq.list is entry on global free page queue
* => uanon is unused (or (void *)0xdeadbeef for DEBUG)
* => uobject is unused (or (void *)0xdeadbeef for DEBUG)
* => PG_FREE is set in flags
* o owned by a uvm_object
* => pageq.queue is entry on wired page queue, if any
* => uanon is NULL or the vm_anon to which it has been O->A loaned
* => uobject is owner
* o owned by a vm_anon
* => pageq is unused (XXX correct?)
* => uanon is owner
* => uobject is NULL
* => PG_ANON is set in flags
* o allocated by uvm_pglistalloc
* => pageq.queue is entry on resulting pglist, owned by caller
* => uanon is unused
* => uobject is unused
*
* The following transitions are allowed:
*
* - uvm_pagealloc: free -> owned by a uvm_object/vm_anon
* - uvm_pagefree: owned by a uvm_object/vm_anon -> free
* - uvm_pglistalloc: free -> allocated by uvm_pglistalloc
* - uvm_pglistfree: allocated by uvm_pglistalloc -> free
*
* On the ordering of fields:
*
* The fields most heavily used during fault processing are clustered
* together at the start of the structure to reduce cache misses.
* XXX This entire thing should be shrunk to fit in one cache line.
*/
struct vm_page {
/* _LP64: first cache line */
union {
TAILQ_ENTRY(vm_page) queue; /* w: wired page queue
* or uvm_pglistalloc output */
LIST_ENTRY(vm_page) list; /* f: global free page queue */
} pageq;
uint32_t pqflags; /* i: pagedaemon flags */
uint32_t flags; /* o: object flags */
paddr_t phys_addr; /* o: physical address of pg */
uint32_t loan_count; /* o,i: num. active loans */
uint32_t wire_count; /* o,i: wired down map refs */
struct vm_anon *uanon; /* o,i: anon */
struct uvm_object *uobject; /* o,i: object */
voff_t offset; /* o: offset into object */
/* _LP64: second cache line */
kmutex_t interlock; /* s: lock on identity */
TAILQ_ENTRY(vm_page) pdqueue; /* p: pagedaemon queue */
#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, stored in pg->flags.
*
* Locking notes:
*
* PG_, struct vm_page::flags => locked by owner
* PG_AOBJ => additionally locked by vm_page::interlock
* PG_ANON => additionally locked by vm_page::interlock
* PG_FREE => additionally locked by uvm_fpageqlock
* for uvm_pglistalloc()
*
* Flag descriptions:
*
* PG_CLEAN:
* Page is known clean.
* The contents of the page is consistent with its backing store.
*
* PG_DIRTY:
* Page is known dirty.
* To avoid losing data, the contents of the page should be written
* back to the backing store before freeing the page.
*
* 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 PQ_WANTED and wait. PG_BUSY may only
* be set with a write lock held on the object.
*
* PG_PAGEOUT:
* Indicates that the page is being paged-out in preparation for
* being freed.
*
* 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_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_RDONLY:
* Indicates that the page must be mapped read-only.
*
* PG_MARKER:
* Dummy marker page, generally used for list traversal.
*/
/*
* if you want to renumber PG_CLEAN and PG_DIRTY, check __CTASSERTs in
* uvm_page_status.c first.
*/
#define PG_CLEAN 0x00000001 /* page is known clean */
#define PG_DIRTY 0x00000002 /* page is known dirty */
#define PG_BUSY 0x00000004 /* page is locked */
#define PG_PAGEOUT 0x00000010 /* page to be freed for pagedaemon */
#define PG_RELEASED 0x00000020 /* page to be freed when unbusied */
#define PG_FAKE 0x00000040 /* page is not yet initialized */
#define PG_RDONLY 0x00000080 /* page must be mapped read-only */
#define PG_TABLED 0x00000200 /* page is tabled in object */
#define PG_AOBJ 0x00000400 /* page is part of an anonymous
uvm_object */
#define PG_ANON 0x00000800 /* page is part of an anon, rather
than an uvm_object */
#define PG_FILE 0x00001000 /* file backed (non-anonymous) */
#define PG_READAHEAD 0x00002000 /* read-ahead but not "hit" yet */
#define PG_FREE 0x00004000 /* page is on free list */
#define PG_MARKER 0x00008000 /* dummy marker page */
#define PG_PAGER1 0x00010000 /* pager-specific flag */
#define PG_PGLCA 0x00020000 /* allocated by uvm_pglistalloc_contig */
#define PG_STAT (PG_ANON|PG_AOBJ|PG_FILE)
#define PG_SWAPBACKED (PG_ANON|PG_AOBJ)
#define UVM_PGFLAGBITS \
"\20\1CLEAN\2DIRTY\3BUSY" \
"\5PAGEOUT\6RELEASED\7FAKE\10RDONLY" \
"\11ZERO\12TABLED\13AOBJ\14ANON" \
"\15FILE\16READAHEAD\17FREE\20MARKER" \
"\21PAGER1\22PGLCA"
/*
* Flags stored in pg->pqflags, which is protected by pg->interlock.
*
* PQ_PRIVATE:
* ... is for uvmpdpol to do whatever it wants with.
*
* PQ_INTENT_SET:
* Indicates that the intent set on the page has not yet been realized.
*
* PQ_INTENT_QUEUED:
* Indicates that the page is, or will soon be, on a per-CPU queue for
* the intent to be realized.
*
* PQ_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).
*/
#define PQ_INTENT_A 0x00000000 /* intend activation */
#define PQ_INTENT_I 0x00000001 /* intend deactivation */
#define PQ_INTENT_E 0x00000002 /* intend enqueue */
#define PQ_INTENT_D 0x00000003 /* intend dequeue */
#define PQ_INTENT_MASK 0x00000003 /* mask of intended state */
#define PQ_INTENT_SET 0x00000004 /* not realized yet */
#define PQ_INTENT_QUEUED 0x00000008 /* queued for processing */
#define PQ_PRIVATE 0x00000ff0 /* private for pdpolicy */
#define PQ_WANTED 0x00001000 /* someone is waiting for page */
#define UVM_PQFLAGBITS \
"\20\1INTENT_0\2INTENT_1\3INTENT_SET\4INTENT_QUEUED" \
"\5PRIVATE1\6PRIVATE2\7PRIVATE3\10PRIVATE4" \
"\11PRIVATE5\12PRIVATE6\13PRIVATE7\14PRIVATE8" \
"\15WANTED"
/*
* 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
#ifdef _KERNEL
/*
* prototypes: the following prototypes define the interface to pages
*/
void uvm_page_init(vaddr_t *, vaddr_t *);
void uvm_pglistalloc_init(void);
#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_page_rebucket(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_pagelock(struct vm_page *);
void uvm_pagelock2(struct vm_page *, struct vm_page *);
void uvm_pageunlock(struct vm_page *);
void uvm_pageunlock2(struct vm_page *, 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_owner_locked_p(struct vm_page *, bool);
void uvm_pgfl_lock(void);
void uvm_pgfl_unlock(void);
unsigned int uvm_pagegetdirty(struct vm_page *);
void uvm_pagemarkdirty(struct vm_page *, unsigned int);
bool uvm_pagecheckdirty(struct vm_page *, bool);
bool uvm_pagereadonly_p(struct vm_page *);
bool uvm_page_locked_p(struct vm_page *);
void uvm_pagewakeup(struct vm_page *);
bool uvm_pagewanted_p(struct vm_page *);
void uvm_pagewait(struct vm_page *, krwlock_t *, const char *);
int uvm_page_lookup_freelist(struct vm_page *);
struct vm_page *uvm_phys_to_vm_page(paddr_t);
paddr_t uvm_vm_page_to_phys(const struct vm_page *);
#if defined(PMAP_DIRECT)
extern bool ubc_direct;
int uvm_direct_process(struct vm_page **, u_int, voff_t, vsize_t,
int (*)(void *, size_t, void *), void *);
#endif
/*
* page dirtiness status for uvm_pagegetdirty and uvm_pagemarkdirty
*
* UNKNOWN means that we need to consult pmap to know if the page is
* dirty or not.
* basically, UVM_PAGE_STATUS_CLEAN implies that the page has no writable
* mapping.
*
* if you want to renumber these, check __CTASSERTs in
* uvm_page_status.c first.
*/
#define UVM_PAGE_STATUS_UNKNOWN 0
#define UVM_PAGE_STATUS_CLEAN 1
#define UVM_PAGE_STATUS_DIRTY 2
#define UVM_PAGE_NUM_STATUS 3
/*
* macros
*/
#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)
#define VM_MD_TO_PAGE(md) (container_of((md), struct vm_page, mdpage))
#endif
/*
* Compute the page color for a given page.
*/
#define VM_PGCOLOR(pg) \
(atop(VM_PAGE_TO_PHYS((pg))) & uvmexp.colormask)
#define PHYS_TO_VM_PAGE(pa) uvm_phys_to_vm_page(pa)
/*
* VM_PAGE_IS_FREE() can't tell if the page is on global free list, or a
* per-CPU cache. If you need to be certain, pause caching.
*/
#define VM_PAGE_IS_FREE(entry) ((entry)->flags & PG_FREE)
/*
* Use the lower 10 bits of pg->phys_addr to cache some some locators for
* the page. This implies that the smallest possible page size is 1kB, and
* that nobody should use pg->phys_addr directly (use VM_PAGE_TO_PHYS()).
*
* - 5 bits for the freelist index, because uvm_page_lookup_freelist()
* traverses an rbtree and therefore features prominently in traces
* captured during performance test. It would probably be more useful to
* cache physseg index here because freelist can be inferred from physseg,
* but it requires changes to allocation for UVM_HOTPLUG, so for now we'll
* go with freelist.
*
* - 5 bits for "bucket", a way for us to categorise pages further as
* needed (e.g. NUMA node).
*
* None of this is set in stone; it can be adjusted as needed.
*/
#define UVM_PHYSADDR_FREELIST __BITS(0,4)
#define UVM_PHYSADDR_BUCKET __BITS(5,9)
static inline unsigned
uvm_page_get_freelist(struct vm_page *pg)
{
unsigned fl = __SHIFTOUT(pg->phys_addr, UVM_PHYSADDR_FREELIST);
KASSERT(fl == (unsigned)uvm_page_lookup_freelist(pg));
return fl;
}
static inline unsigned
uvm_page_get_bucket(struct vm_page *pg)
{
return __SHIFTOUT(pg->phys_addr, UVM_PHYSADDR_BUCKET);
}
static inline void
uvm_page_set_freelist(struct vm_page *pg, unsigned fl)
{
KASSERT(fl < 32);
pg->phys_addr &= ~UVM_PHYSADDR_FREELIST;
pg->phys_addr |= __SHIFTIN(fl, UVM_PHYSADDR_FREELIST);
}
static inline void
uvm_page_set_bucket(struct vm_page *pg, unsigned b)
{
KASSERT(b < 32);
pg->phys_addr &= ~UVM_PHYSADDR_BUCKET;
pg->phys_addr |= __SHIFTIN(b, UVM_PHYSADDR_BUCKET);
}
#endif /* _KERNEL */
#endif /* _UVM_UVM_PAGE_H_ */
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