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NetBSD/sys/uvm/uvm_map.h
atatat df0a9badc6 Introduce "top down" memory management for mmap()ed allocations. This 
means that the dynamic linker gets mapped in at the top of available
user virtual memory (typically just below the stack), shared libraries
get mapped downwards from that point, and calls to mmap() that don't
specify a preferred address will get mapped in below those.

This means that the heap and the mmap()ed allocations will grow
towards each other, allowing one or the other to grow larger than
before.  Previously, the heap was limited to MAXDSIZ by the placement
of the dynamic linker (and the process's rlimits) and the space
available to mmap was hobbled by this reservation.

This is currently only enabled via an *option* for the i386 platform
(though other platforms are expected to follow).  Add "options
USE_TOPDOWN_VM" to your kernel config file, rerun config, and rebuild
your kernel to take advantage of this.

Note that the pmap_prefer() interface has not yet been modified to
play nicely with this, so those platforms require a bit more work
(most notably the sparc) before they can use this new memory
arrangement.

This change also introduces a VM_DEFAULT_ADDRESS() macro that picks
the appropriate default address based on the size of the allocation or
the size of the process's text segment accordingly.  Several drivers
and the SYSV SHM address assignment were changed to use this instead
of each one picking their own "default".
2003-02-20 22:16:05 +00:00

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/* $NetBSD: uvm_map.h,v 1.34 2003/02/20 22:16:08 atatat 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. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by Charles D. Cranor,
* Washington University, 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.
*
* @(#)vm_map.h 8.3 (Berkeley) 3/15/94
* from: Id: uvm_map.h,v 1.1.2.3 1998/02/07 01:16:55 chs 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_MAP_H_
#define _UVM_UVM_MAP_H_
/*
* uvm_map.h
*/
#ifdef _KERNEL
/*
* macros
*/
/*
* UVM_MAP_CLIP_START: ensure that the entry begins at or after
* the starting address, if it doesn't we split the entry.
*
* => map must be locked by caller
*/
#define UVM_MAP_CLIP_START(MAP,ENTRY,VA) { \
if ((VA) > (ENTRY)->start) uvm_map_clip_start(MAP,ENTRY,VA); }
/*
* UVM_MAP_CLIP_END: ensure that the entry ends at or before
* the ending address, if it does't we split the entry.
*
* => map must be locked by caller
*/
#define UVM_MAP_CLIP_END(MAP,ENTRY,VA) { \
if ((VA) < (ENTRY)->end) uvm_map_clip_end(MAP,ENTRY,VA); }
/*
* extract flags
*/
#define UVM_EXTRACT_REMOVE 0x1 /* remove mapping from old map */
#define UVM_EXTRACT_CONTIG 0x2 /* try to keep it contig */
#define UVM_EXTRACT_QREF 0x4 /* use quick refs */
#define UVM_EXTRACT_FIXPROT 0x8 /* set prot to maxprot as we go */
#endif /* _KERNEL */
#include <uvm/uvm_anon.h>
/*
* Address map entries consist of start and end addresses,
* a VM object (or sharing map) and offset into that object,
* and user-exported inheritance and protection information.
* Also included is control information for virtual copy operations.
*/
struct vm_map_entry {
struct vm_map_entry *prev; /* previous entry */
struct vm_map_entry *next; /* next entry */
vaddr_t start; /* start address */
vaddr_t end; /* end address */
union {
struct uvm_object *uvm_obj; /* uvm object */
struct vm_map *sub_map; /* belongs to another map */
} object; /* object I point to */
voff_t offset; /* offset into object */
int etype; /* entry type */
vm_prot_t protection; /* protection code */
vm_prot_t max_protection; /* maximum protection */
vm_inherit_t inheritance; /* inheritance */
int wired_count; /* can be paged if == 0 */
struct vm_aref aref; /* anonymous overlay */
int advice; /* madvise advice */
#define uvm_map_entry_stop_copy flags
u_int8_t flags; /* flags */
#define UVM_MAP_STATIC 0x01 /* static map entry */
#define UVM_MAP_KMEM 0x02 /* from kmem entry pool */
};
#define VM_MAPENT_ISWIRED(entry) ((entry)->wired_count != 0)
/*
* Maps are doubly-linked lists of map entries, kept sorted
* by address. A single hint is provided to start
* searches again from the last successful search,
* insertion, or removal.
*
* LOCKING PROTOCOL NOTES:
* -----------------------
*
* VM map locking is a little complicated. There are both shared
* and exclusive locks on maps. However, it is sometimes required
* to downgrade an exclusive lock to a shared lock, and upgrade to
* an exclusive lock again (to perform error recovery). However,
* another thread *must not* queue itself to receive an exclusive
* lock while before we upgrade back to exclusive, otherwise the
* error recovery becomes extremely difficult, if not impossible.
*
* In order to prevent this scenario, we introduce the notion of
* a `busy' map. A `busy' map is read-locked, but other threads
* attempting to write-lock wait for this flag to clear before
* entering the lock manager. A map may only be marked busy
* when the map is write-locked (and then the map must be downgraded
* to read-locked), and may only be marked unbusy by the thread
* which marked it busy (holding *either* a read-lock or a
* write-lock, the latter being gained by an upgrade).
*
* Access to the map `flags' member is controlled by the `flags_lock'
* simple lock. Note that some flags are static (set once at map
* creation time, and never changed), and thus require no locking
* to check those flags. All flags which are r/w must be set or
* cleared while the `flags_lock' is asserted. Additional locking
* requirements are:
*
* VM_MAP_PAGEABLE r/o static flag; no locking required
*
* VM_MAP_INTRSAFE r/o static flag; no locking required
*
* VM_MAP_WIREFUTURE r/w; may only be set or cleared when
* map is write-locked. may be tested
* without asserting `flags_lock'.
*
* VM_MAP_BUSY r/w; may only be set when map is
* write-locked, may only be cleared by
* thread which set it, map read-locked
* or write-locked. must be tested
* while `flags_lock' is asserted.
*
* VM_MAP_WANTLOCK r/w; may only be set when the map
* is busy, and thread is attempting
* to write-lock. must be tested
* while `flags_lock' is asserted.
*
* VM_MAP_DYING r/o; set when a vmspace is being
* destroyed to indicate that updates
* to the pmap can be skipped.
*
* VM_MAP_TOPDOWN r/o; set when the vmspace is
* created if the unspecified map
* allocations are to be arranged in
* a "top down" manner.
*/
struct vm_map {
struct pmap * pmap; /* Physical map */
struct lock lock; /* Lock for map data */
struct vm_map_entry header; /* List of entries */
int nentries; /* Number of entries */
vsize_t size; /* virtual size */
int ref_count; /* Reference count */
struct simplelock ref_lock; /* Lock for ref_count field */
struct vm_map_entry * hint; /* hint for quick lookups */
struct simplelock hint_lock; /* lock for hint storage */
struct vm_map_entry * first_free; /* First free space hint */
int flags; /* flags */
struct simplelock flags_lock; /* Lock for flags field */
unsigned int timestamp; /* Version number */
#define min_offset header.start
#define max_offset header.end
};
/* vm_map flags */
#define VM_MAP_PAGEABLE 0x01 /* ro: entries are pageable */
#define VM_MAP_INTRSAFE 0x02 /* ro: interrupt safe map */
#define VM_MAP_WIREFUTURE 0x04 /* rw: wire future mappings */
#define VM_MAP_BUSY 0x08 /* rw: map is busy */
#define VM_MAP_WANTLOCK 0x10 /* rw: want to write-lock */
#define VM_MAP_DYING 0x20 /* rw: map is being destroyed */
#define VM_MAP_TOPDOWN 0x40 /* ro: arrange map top-down */
/* XXX: number of kernel maps and entries to statically allocate */
#if !defined(MAX_KMAPENT)
#if (50 + (2 * NPROC) > 1000)
#define MAX_KMAPENT (50 + (2 * NPROC))
#else
#define MAX_KMAPENT 1000 /* XXXCDC: no crash */
#endif
#endif /* !defined MAX_KMAPENT */
#ifdef _KERNEL
#define vm_map_modflags(map, set, clear) \
do { \
simple_lock(&(map)->flags_lock); \
(map)->flags = ((map)->flags | (set)) & ~(clear); \
simple_unlock(&(map)->flags_lock); \
} while (/*CONSTCOND*/ 0)
#endif /* _KERNEL */
/*
* handle inline options
*/
#ifdef UVM_MAP_INLINE
#define MAP_INLINE static __inline
#else
#define MAP_INLINE /* nothing */
#endif /* UVM_MAP_INLINE */
/*
* globals:
*/
#ifdef _KERNEL
#ifdef PMAP_GROWKERNEL
extern vaddr_t uvm_maxkaddr;
#endif
/*
* protos: the following prototypes define the interface to vm_map
*/
MAP_INLINE
void uvm_map_deallocate __P((struct vm_map *));
int uvm_map_clean __P((struct vm_map *, vaddr_t, vaddr_t, int));
void uvm_map_clip_start __P((struct vm_map *, struct vm_map_entry *,
vaddr_t));
void uvm_map_clip_end __P((struct vm_map *, struct vm_map_entry *,
vaddr_t));
MAP_INLINE
struct vm_map *uvm_map_create __P((pmap_t, vaddr_t, vaddr_t, int));
int uvm_map_extract __P((struct vm_map *, vaddr_t, vsize_t,
struct vm_map *, vaddr_t *, int));
struct vm_map_entry *uvm_map_findspace __P((struct vm_map *, vaddr_t, vsize_t,
vaddr_t *, struct uvm_object *, voff_t, vsize_t, int));
int uvm_map_inherit __P((struct vm_map *, vaddr_t, vaddr_t,
vm_inherit_t));
int uvm_map_advice __P((struct vm_map *, vaddr_t, vaddr_t, int));
void uvm_map_init __P((void));
boolean_t uvm_map_lookup_entry __P((struct vm_map *, vaddr_t,
struct vm_map_entry **));
MAP_INLINE
void uvm_map_reference __P((struct vm_map *));
int uvm_map_replace __P((struct vm_map *, vaddr_t, vaddr_t,
struct vm_map_entry *, int));
int uvm_map_reserve __P((struct vm_map *, vsize_t, vaddr_t, vsize_t,
vaddr_t *));
void uvm_map_setup __P((struct vm_map *, vaddr_t, vaddr_t, int));
int uvm_map_submap __P((struct vm_map *, vaddr_t, vaddr_t,
struct vm_map *));
MAP_INLINE
void uvm_unmap __P((struct vm_map *, vaddr_t, vaddr_t));
void uvm_unmap_detach __P((struct vm_map_entry *,int));
void uvm_unmap_remove __P((struct vm_map *, vaddr_t, vaddr_t,
struct vm_map_entry **));
#endif /* _KERNEL */
/*
* VM map locking operations:
*
* These operations perform locking on the data portion of the
* map.
*
* vm_map_lock_try: try to lock a map, failing if it is already locked.
*
* vm_map_lock: acquire an exclusive (write) lock on a map.
*
* vm_map_lock_read: acquire a shared (read) lock on a map.
*
* vm_map_unlock: release an exclusive lock on a map.
*
* vm_map_unlock_read: release a shared lock on a map.
*
* vm_map_downgrade: downgrade an exclusive lock to a shared lock.
*
* vm_map_upgrade: upgrade a shared lock to an exclusive lock.
*
* vm_map_busy: mark a map as busy.
*
* vm_map_unbusy: clear busy status on a map.
*
* Note that "intrsafe" maps use only exclusive, spin locks. We simply
* use the sleep lock's interlock for this.
*/
#ifdef _KERNEL
/* XXX: clean up later */
#include <sys/time.h>
#include <sys/proc.h> /* for tsleep(), wakeup() */
#include <sys/systm.h> /* for panic() */
static __inline boolean_t vm_map_lock_try __P((struct vm_map *));
static __inline void vm_map_lock __P((struct vm_map *));
extern const char vmmapbsy[];
static __inline boolean_t
vm_map_lock_try(map)
struct vm_map *map;
{
boolean_t rv;
if (map->flags & VM_MAP_INTRSAFE)
rv = simple_lock_try(&map->lock.lk_interlock);
else {
simple_lock(&map->flags_lock);
if (map->flags & VM_MAP_BUSY) {
simple_unlock(&map->flags_lock);
return (FALSE);
}
rv = (lockmgr(&map->lock, LK_EXCLUSIVE|LK_NOWAIT|LK_INTERLOCK,
&map->flags_lock) == 0);
}
if (rv)
map->timestamp++;
return (rv);
}
static __inline void
vm_map_lock(map)
struct vm_map *map;
{
int error;
if (map->flags & VM_MAP_INTRSAFE) {
simple_lock(&map->lock.lk_interlock);
return;
}
try_again:
simple_lock(&map->flags_lock);
while (map->flags & VM_MAP_BUSY) {
map->flags |= VM_MAP_WANTLOCK;
ltsleep(&map->flags, PVM, vmmapbsy, 0, &map->flags_lock);
}
error = lockmgr(&map->lock, LK_EXCLUSIVE|LK_SLEEPFAIL|LK_INTERLOCK,
&map->flags_lock);
if (error) {
KASSERT(error == ENOLCK);
goto try_again;
}
(map)->timestamp++;
}
#ifdef DIAGNOSTIC
#define vm_map_lock_read(map) \
do { \
if ((map)->flags & VM_MAP_INTRSAFE) \
panic("vm_map_lock_read: intrsafe Map"); \
(void) lockmgr(&(map)->lock, LK_SHARED, NULL); \
} while (/*CONSTCOND*/ 0)
#else
#define vm_map_lock_read(map) \
(void) lockmgr(&(map)->lock, LK_SHARED, NULL)
#endif
#define vm_map_unlock(map) \
do { \
if ((map)->flags & VM_MAP_INTRSAFE) \
simple_unlock(&(map)->lock.lk_interlock); \
else \
(void) lockmgr(&(map)->lock, LK_RELEASE, NULL); \
} while (/*CONSTCOND*/ 0)
#define vm_map_unlock_read(map) \
(void) lockmgr(&(map)->lock, LK_RELEASE, NULL)
#define vm_map_downgrade(map) \
(void) lockmgr(&(map)->lock, LK_DOWNGRADE, NULL)
#ifdef DIAGNOSTIC
#define vm_map_upgrade(map) \
do { \
if (lockmgr(&(map)->lock, LK_UPGRADE, NULL) != 0) \
panic("vm_map_upgrade: failed to upgrade lock"); \
} while (/*CONSTCOND*/ 0)
#else
#define vm_map_upgrade(map) \
(void) lockmgr(&(map)->lock, LK_UPGRADE, NULL)
#endif
#define vm_map_busy(map) \
do { \
simple_lock(&(map)->flags_lock); \
(map)->flags |= VM_MAP_BUSY; \
simple_unlock(&(map)->flags_lock); \
} while (/*CONSTCOND*/ 0)
#define vm_map_unbusy(map) \
do { \
int oflags; \
\
simple_lock(&(map)->flags_lock); \
oflags = (map)->flags; \
(map)->flags &= ~(VM_MAP_BUSY|VM_MAP_WANTLOCK); \
simple_unlock(&(map)->flags_lock); \
if (oflags & VM_MAP_WANTLOCK) \
wakeup(&(map)->flags); \
} while (/*CONSTCOND*/ 0)
#endif /* _KERNEL */
/*
* Functions implemented as macros
*/
#define vm_map_min(map) ((map)->min_offset)
#define vm_map_max(map) ((map)->max_offset)
#define vm_map_pmap(map) ((map)->pmap)
#endif /* _UVM_UVM_MAP_H_ */
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