diff options
author | alc <alc@FreeBSD.org> | 1999-03-27 23:46:04 +0000 |
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committer | alc <alc@FreeBSD.org> | 1999-03-27 23:46:04 +0000 |
commit | a976359db5d220f9d0383d311a28bbc14d35e6b4 (patch) | |
tree | 09afa5ff9f0122bec48374e3b643656db4c3953e /sys/vm/vm_map.c | |
parent | 41a1880724f3d81fdbcaa85188f37f5784a5a419 (diff) | |
download | FreeBSD-src-a976359db5d220f9d0383d311a28bbc14d35e6b4.zip FreeBSD-src-a976359db5d220f9d0383d311a28bbc14d35e6b4.tar.gz |
Mainly, eliminate the comments about share maps. (We don't have share maps
any more.) Also, eliminate an incorrect comment that says that we don't
coalesce vm_map_entry's. (We do.)
Diffstat (limited to 'sys/vm/vm_map.c')
-rw-r--r-- | sys/vm/vm_map.c | 40 |
1 files changed, 7 insertions, 33 deletions
diff --git a/sys/vm/vm_map.c b/sys/vm/vm_map.c index 824c6aa..84dd7d2 100644 --- a/sys/vm/vm_map.c +++ b/sys/vm/vm_map.c @@ -61,7 +61,7 @@ * any improvements or extensions that they make and grant Carnegie the * rights to redistribute these changes. * - * $Id: vm_map.c,v 1.157 1999/03/15 06:24:52 alc Exp $ + * $Id: vm_map.c,v 1.158 1999/03/21 23:37:00 alc Exp $ */ /* @@ -104,18 +104,6 @@ * Maps consist of an ordered doubly-linked list of simple * entries; a single hint is used to speed up lookups. * - * In order to properly represent the sharing of virtual - * memory regions among maps, the map structure is bi-level. - * Top-level ("address") maps refer to regions of sharable - * virtual memory. These regions are implemented as - * ("sharing") maps, which then refer to the actual virtual - * memory objects. When two address maps "share" memory, - * their top-level maps both have references to the same - * sharing map. When memory is virtual-copied from one - * address map to another, the references in the sharing - * maps are actually copied -- no copying occurs at the - * virtual memory object level. - * * Since portions of maps are specified by start/end addreses, * which may not align with existing map entries, all * routines merely "clip" entries to these start/end values. @@ -123,16 +111,10 @@ * start or end value.] Note that these clippings may not * always be necessary (as the two resulting entries are then * not changed); however, the clipping is done for convenience. - * No attempt is currently made to "glue back together" two - * abutting entries. * * As mentioned above, virtual copy operations are performed - * by copying VM object references from one sharing map to + * by copying VM object references from one map to * another, and then marking both regions as copy-on-write. - * It is important to note that only one writeable reference - * to a VM object region exists in any map -- this means that - * shadow object creation can be delayed until a write operation - * occurs. */ /* @@ -1647,8 +1629,8 @@ vm_map_pageable(map, start, end, new_pageable) * object for a zero-fill region. * * We don't have to do this for entries that - * point to sharing maps, because we won't - * hold the lock on the sharing map. + * point to sub maps, because we won't + * hold the lock on the sub map. */ if ((entry->eflags & MAP_ENTRY_IS_SUB_MAP) == 0) { int copyflag = entry->eflags & MAP_ENTRY_NEEDS_COPY; @@ -1920,9 +1902,6 @@ vm_map_entry_delete(map, entry) * * Deallocates the given address range from the target * map. - * - * When called with a sharing map, removes pages from - * that region from all physical maps. */ int vm_map_delete(map, start, end) @@ -1991,11 +1970,6 @@ vm_map_delete(map, start, end) } offidxend = offidxstart + count; - /* - * If this is a sharing map, we must remove *all* references - * to this data, since we can't find all of the physical maps - * which are sharing it. - */ if ((object == kernel_object) || (object == kmem_object)) { vm_object_page_remove(object, offidxstart, offidxend, FALSE); @@ -2322,7 +2296,7 @@ vmspace_fork(vm1) vm_object_clear_flag(object, OBJ_ONEMAPPING); /* - * Clone the entry, referencing the sharing map. + * Clone the entry, referencing the shared object. */ new_entry = vm_map_entry_create(new_map); *new_entry = *old_entry; @@ -2543,7 +2517,7 @@ RetryLookup:; if (entry->eflags & MAP_ENTRY_NEEDS_COPY) { /* * If we want to write the page, we may as well handle that - * now since we've got the sharing map locked. + * now since we've got the map locked. * * If we don't need to write the page, we just demote the * permissions allowed. @@ -2553,7 +2527,7 @@ RetryLookup:; /* * Make a new object, and place it in the object * chain. Note that no new references have appeared - * -- one just moved from the share map to the new + * -- one just moved from the map to the new * object. */ |