/* $NetBSD: uvm_page.h,v 1.84.4.1 2020/05/13 18:05:14 martin 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 #include #include /* * 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) * p: page queue lock, uvm_pageqlock * o,p: o|p for read, o&p for write * w: wired page queue or uvm_pglistalloc: * => wired page queue: o&p 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 * * UVM and pmap(9) may use uvm_page_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 * => listq.list is entry on per-CPU free page queue * => uanon is unused (or (void *)0xdeadbeef for DEBUG) * => uobject is unused (or (void *)0xdeadbeef for DEBUG) * => PQ_FREE is set in pqflags * o owned by a uvm_object * => pageq.queue is entry on wired page queue, if any * => listq.queue is entry on list of pages in object * => 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?) * => listq is unused (XXX correct?) * => uanon is owner * => uobject is NULL * => PQ_ANON is set in pqflags * o allocated by uvm_pglistalloc * => pageq.queue is entry on resulting pglist, owned by caller * => listq is unused (XXX correct?) * => 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 */ struct vm_page { struct rb_node rb_node; /* o: tree of pages in obj */ 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; union { TAILQ_ENTRY(vm_page) queue; /* o: pages in same object */ LIST_ENTRY(vm_page) list; /* f: CPU free page queue */ } listq; 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; /* o,p: num. active loans */ 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 owner * PQ_, struct vm_page::pqflags => locked by uvm_pageqlock * PQ_FREE => additionally locked by uvm_fpageqlock * * 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 #ifdef _KERNEL /* * globals */ extern bool vm_page_zero_enable; /* * 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 *); 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 /* * 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_ */