e225b7bd09
- Reorganize locking in UVM and provide extra serialisation for pmap(9). New lock order: [vmpage-owner-lock] -> pmap-lock. - Simplify locking in some pmap(9) modules by removing P->V locking. - Use lock object on vmobjlock (and thus vnode_t::v_interlock) to share the locks amongst UVM objects where necessary (tmpfs, layerfs, unionfs). - Rewrite and optimise x86 TLB shootdown code, make it simpler and cleaner. Add TLBSTATS option for x86 to collect statistics about TLB shootdowns. - Unify /dev/mem et al in MI code and provide required locking (removes kernel-lock on some ports). Also, avoid cache-aliasing issues. Thanks to Andrew Doran and Joerg Sonnenberger, as their initial patches formed the core changes of this branch.
280 lines
9.8 KiB
C
280 lines
9.8 KiB
C
/* $NetBSD: uvm_amap.h,v 1.37 2011/06/12 03:36:02 rmind Exp $ */
|
|
|
|
/*
|
|
* Copyright (c) 1997 Charles D. Cranor and Washington University.
|
|
* All rights reserved.
|
|
*
|
|
* 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.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
|
|
*/
|
|
|
|
#ifndef _UVM_UVM_AMAP_H_
|
|
#define _UVM_UVM_AMAP_H_
|
|
|
|
/*
|
|
* uvm_amap.h: general amap interface and amap implementation-specific info
|
|
*/
|
|
|
|
/*
|
|
* an amap structure contains pointers to a set of anons that are
|
|
* mapped together in virtual memory (an anon is a single page of
|
|
* anonymous virtual memory -- see uvm_anon.h). in uvm we hide the
|
|
* details of the implementation of amaps behind a general amap
|
|
* interface. this allows us to change the amap implementation
|
|
* without having to touch the rest of the code. this file is divided
|
|
* into two parts: the definition of the uvm amap interface and the
|
|
* amap implementation-specific definitions.
|
|
*/
|
|
|
|
#ifdef _KERNEL
|
|
|
|
/*
|
|
* part 1: amap interface
|
|
*/
|
|
|
|
void uvm_amap_init(void);
|
|
|
|
/*
|
|
* forward definition of vm_amap structure. only amap
|
|
* implementation-specific code should directly access the fields of
|
|
* this structure.
|
|
*/
|
|
|
|
struct vm_amap;
|
|
|
|
|
|
/*
|
|
* prototypes for the amap interface
|
|
*/
|
|
|
|
void amap_add /* add an anon to an amap */
|
|
(struct vm_aref *, vaddr_t,
|
|
struct vm_anon *, bool);
|
|
struct vm_amap *amap_alloc /* allocate a new amap */
|
|
(vaddr_t, vaddr_t, int);
|
|
void amap_copy /* clear amap needs-copy flag */
|
|
(struct vm_map *, struct vm_map_entry *, int,
|
|
vaddr_t, vaddr_t);
|
|
void amap_cow_now /* resolve all COW faults now */
|
|
(struct vm_map *, struct vm_map_entry *);
|
|
int amap_extend /* make amap larger */
|
|
(struct vm_map_entry *, vsize_t, int);
|
|
int amap_flags /* get amap's flags */
|
|
(struct vm_amap *);
|
|
void amap_free /* free amap */
|
|
(struct vm_amap *);
|
|
void amap_lock /* lock amap */
|
|
(struct vm_amap *);
|
|
struct vm_anon *amap_lookup /* lookup an anon @ offset in amap */
|
|
(struct vm_aref *, vaddr_t);
|
|
void amap_lookups /* lookup multiple anons */
|
|
(struct vm_aref *, vaddr_t,
|
|
struct vm_anon **, int);
|
|
void amap_ref /* add a reference to an amap */
|
|
(struct vm_amap *, vaddr_t, vsize_t, int);
|
|
int amap_refs /* get number of references of amap */
|
|
(struct vm_amap *);
|
|
void amap_share_protect /* protect pages in a shared amap */
|
|
(struct vm_map_entry *, vm_prot_t);
|
|
void amap_splitref /* split reference to amap into two */
|
|
(struct vm_aref *, struct vm_aref *, vaddr_t);
|
|
void amap_unadd /* remove an anon from an amap */
|
|
(struct vm_aref *, vaddr_t);
|
|
void amap_unlock /* unlock amap */
|
|
(struct vm_amap *);
|
|
void amap_unref /* drop reference to an amap */
|
|
(struct vm_amap *, vaddr_t, vsize_t, bool);
|
|
void amap_wipeout /* remove all anons from amap */
|
|
(struct vm_amap *);
|
|
bool amap_swap_off
|
|
(int, int);
|
|
|
|
/*
|
|
* amap flag values
|
|
*/
|
|
|
|
#define AMAP_SHARED 0x1 /* amap is shared */
|
|
#define AMAP_REFALL 0x2 /* amap_ref: reference entire amap */
|
|
#define AMAP_SWAPOFF 0x4 /* amap_swap_off() is in progress */
|
|
|
|
/*
|
|
* amap_copy flags
|
|
*/
|
|
|
|
#define AMAP_COPY_NOWAIT 0x02 /* not allowed to sleep */
|
|
#define AMAP_COPY_NOCHUNK 0x04 /* not allowed to chunk */
|
|
#define AMAP_COPY_NOMERGE 0x08 /* not allowed to merge */
|
|
|
|
/*
|
|
* amap_extend flags
|
|
*/
|
|
#define AMAP_EXTEND_BACKWARDS 0x00 /* add "size" to start of map */
|
|
#define AMAP_EXTEND_FORWARDS 0x01 /* add "size" to end of map */
|
|
#define AMAP_EXTEND_NOWAIT 0x02 /* not allowed to sleep */
|
|
|
|
#endif /* _KERNEL */
|
|
|
|
/**********************************************************************/
|
|
|
|
/*
|
|
* part 2: amap implementation-specific info
|
|
*/
|
|
|
|
/*
|
|
* we currently provide an array-based amap implementation. in this
|
|
* implementation we provide the option of tracking split references
|
|
* so that we don't lose track of references during partial unmaps
|
|
* ... this is enabled with the "UVM_AMAP_PPREF" define.
|
|
*/
|
|
|
|
#define UVM_AMAP_PPREF /* track partial references */
|
|
|
|
/*
|
|
* here is the definition of the vm_amap structure for this implementation.
|
|
*/
|
|
|
|
struct vm_amap {
|
|
kmutex_t *am_lock; /* lock [locks all vm_amap fields] */
|
|
int am_ref; /* reference count */
|
|
int am_flags; /* flags */
|
|
int am_maxslot; /* max # of slots allocated */
|
|
int am_nslot; /* # of slots currently in map ( <= maxslot) */
|
|
int am_nused; /* # of slots currently in use */
|
|
int *am_slots; /* contig array of active slots */
|
|
int *am_bckptr; /* back pointer array to am_slots */
|
|
struct vm_anon **am_anon; /* array of anonymous pages */
|
|
#ifdef UVM_AMAP_PPREF
|
|
int *am_ppref; /* per page reference count (if !NULL) */
|
|
#endif
|
|
LIST_ENTRY(vm_amap) am_list;
|
|
};
|
|
|
|
/*
|
|
* note that am_slots, am_bckptr, and am_anon are arrays. this allows
|
|
* fast lookup of pages based on their virual address at the expense of
|
|
* some extra memory. in the future we should be smarter about memory
|
|
* usage and fall back to a non-array based implementation on systems
|
|
* that are short of memory (XXXCDC).
|
|
*
|
|
* the entries in the array are called slots... for example an amap that
|
|
* covers four pages of virtual memory is said to have four slots. here
|
|
* is an example of the array usage for a four slot amap. note that only
|
|
* slots one and three have anons assigned to them. "D/C" means that we
|
|
* "don't care" about the value.
|
|
*
|
|
* 0 1 2 3
|
|
* am_anon: NULL, anon0, NULL, anon1 (actual pointers to anons)
|
|
* am_bckptr: D/C, 1, D/C, 0 (points to am_slots entry)
|
|
*
|
|
* am_slots: 3, 1, D/C, D/C (says slots 3 and 1 are in use)
|
|
*
|
|
* note that am_bckptr is D/C if the slot in am_anon is set to NULL.
|
|
* to find the entry in am_slots for an anon, look at am_bckptr[slot],
|
|
* thus the entry for slot 3 in am_slots[] is at am_slots[am_bckptr[3]].
|
|
* in general, if am_anon[X] is non-NULL, then the following must be
|
|
* true: am_slots[am_bckptr[X]] == X
|
|
*
|
|
* note that am_slots is always contig-packed.
|
|
*/
|
|
|
|
/*
|
|
* defines for handling of large, sparse amaps:
|
|
*
|
|
* one of the problems of array-based amaps is that if you allocate a
|
|
* large, sparsely-used area of virtual memory you end up allocating
|
|
* large arrays that, for the most part, don't get used. this is a
|
|
* problem for BSD in that the kernel likes to make these types of
|
|
* allocations to "reserve" memory for possible future use.
|
|
*
|
|
* for example, the kernel allocates (reserves) a large chunk of user
|
|
* VM for possible stack growth. most of the time only a page or two
|
|
* of this VM is actually used. since the stack is anonymous memory
|
|
* it makes sense for it to live in an amap, but if we allocated an
|
|
* amap for the entire stack range we could end up wasting a large
|
|
* amount of allocated KVM.
|
|
*
|
|
* for example, on the i386 at boot time we allocate two amaps for the stack
|
|
* of /sbin/init:
|
|
* 1. a 7680 slot amap at protection 0 (reserve space for stack)
|
|
* 2. a 512 slot amap at protection 7 (top of stack)
|
|
*
|
|
* most of the array allocated for the amaps for this is never used.
|
|
* the amap interface provides a way for us to avoid this problem by
|
|
* allowing amap_copy() to break larger amaps up into smaller sized
|
|
* chunks (controlled by the "canchunk" option). we use this feature
|
|
* to reduce our memory usage with the BSD stack management. if we
|
|
* are asked to create an amap with more than UVM_AMAP_LARGE slots in it,
|
|
* we attempt to break it up into a UVM_AMAP_CHUNK sized amap if the
|
|
* "canchunk" flag is set.
|
|
*
|
|
* so, in the i386 example, the 7680 slot area is never referenced so
|
|
* nothing gets allocated (amap_copy is never called because the protection
|
|
* is zero). the 512 slot area for the top of the stack is referenced.
|
|
* the chunking code breaks it up into 16 slot chunks (hopefully a single
|
|
* 16 slot chunk is enough to handle the whole stack).
|
|
*/
|
|
|
|
#define UVM_AMAP_LARGE 256 /* # of slots in "large" amap */
|
|
#define UVM_AMAP_CHUNK 16 /* # of slots to chunk large amaps in */
|
|
|
|
#ifdef _KERNEL
|
|
|
|
/*
|
|
* macros
|
|
*/
|
|
|
|
/* AMAP_B2SLOT: convert byte offset to slot */
|
|
#define AMAP_B2SLOT(S,B) { \
|
|
KASSERT(((B) & (PAGE_SIZE - 1)) == 0); \
|
|
(S) = (B) >> PAGE_SHIFT; \
|
|
}
|
|
|
|
/*
|
|
* lock/unlock/refs/flags macros
|
|
*/
|
|
|
|
#define amap_flags(AMAP) ((AMAP)->am_flags)
|
|
#define amap_lock(AMAP) mutex_enter((AMAP)->am_lock)
|
|
#define amap_lock_try(AMAP) mutex_tryenter((AMAP)->am_lock)
|
|
#define amap_refs(AMAP) ((AMAP)->am_ref)
|
|
#define amap_unlock(AMAP) mutex_exit((AMAP)->am_lock)
|
|
|
|
/*
|
|
* if we enable PPREF, then we have a couple of extra functions that
|
|
* we need to prototype here...
|
|
*/
|
|
|
|
#ifdef UVM_AMAP_PPREF
|
|
|
|
#define PPREF_NONE ((int *) -1) /* not using ppref */
|
|
|
|
void amap_pp_adjref /* adjust references */
|
|
(struct vm_amap *, int, vsize_t, int,
|
|
struct vm_anon **);
|
|
void amap_pp_establish /* establish ppref */
|
|
(struct vm_amap *, vaddr_t);
|
|
void amap_wiperange /* wipe part of an amap */
|
|
(struct vm_amap *, int, int, struct vm_anon **);
|
|
#endif /* UVM_AMAP_PPREF */
|
|
|
|
#endif /* _KERNEL */
|
|
|
|
#endif /* _UVM_UVM_AMAP_H_ */
|