/*      $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  [email protected]
*  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_ */

You are viewing proxied material from ftp.icm.edu.pl. The copyright of proxied material belongs to its original authors. Any comments or complaints in relation to proxied material should be directed to the original authors of the content concerned. Please see the disclaimer for more details.