From 7fd2f69ac581f1906241fcb53d9bd2dae40f7c24 Mon Sep 17 00:00:00 2001 From: alc Date: Fri, 13 Aug 1999 17:45:34 +0000 Subject: vm_map_madvise: A complete rewrite by dillon and myself to separate the implementation of behaviors that effect the vm_map_entry from those that effect the vm_object. A result of this change is that madvise(..., MADV_FREE); is much cheaper. --- sys/vm/vm_map.c | 145 +++++++++++++++++++++++++++++++++----------------------- 1 file changed, 85 insertions(+), 60 deletions(-) (limited to 'sys/vm/vm_map.c') diff --git a/sys/vm/vm_map.c b/sys/vm/vm_map.c index 8fd5eb7..6ea4395 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 1.174 1999/08/01 06:05:08 alc Exp $ + * $Id: vm_map.c,v 1.175 1999/08/10 04:50:20 alc Exp $ */ /* @@ -1005,88 +1005,113 @@ vm_map_protect(vm_map_t map, vm_offset_t start, vm_offset_t end, * vm_map_madvise: * * This routine traverses a processes map handling the madvise - * system call. + * system call. Advisories are classified as either those effecting + * the vm_map_entry structure, or those effecting the underlying + * objects. */ void -vm_map_madvise(map, start, end, advise) +vm_map_madvise(map, start, end, behav) vm_map_t map; vm_offset_t start, end; - int advise; + int behav; { - vm_map_entry_t current; - vm_map_entry_t entry; + vm_map_entry_t current, entry; + int modify_map; - vm_map_lock(map); + modify_map = (behav == MADV_NORMAL || behav == MADV_SEQUENTIAL || + behav == MADV_RANDOM); + + if (modify_map) { + vm_map_lock(map); + } + else + vm_map_lock_read(map); VM_MAP_RANGE_CHECK(map, start, end); if (vm_map_lookup_entry(map, start, &entry)) { - vm_map_clip_start(map, entry, start); + if (modify_map) + vm_map_clip_start(map, entry, start); } else entry = entry->next; - for(current = entry; - (current != &map->header) && (current->start < end); - current = current->next) { + if (modify_map) { + /* + * madvise behaviors that are implemented in the vm_map_entry. + * + * We clip the vm_map_entry so that behavioral changes are + * limited to the specified address range. + */ + for (current = entry; + (current != &map->header) && (current->start < end); + current = current->next) { - if (current->eflags & MAP_ENTRY_IS_SUB_MAP) { - continue; + if (current->eflags & MAP_ENTRY_IS_SUB_MAP) + continue; + + vm_map_clip_end(map, current, end); + + switch (behav) { + case MADV_NORMAL: + vm_map_entry_set_behavior(current, MAP_ENTRY_BEHAV_NORMAL); + break; + case MADV_SEQUENTIAL: + vm_map_entry_set_behavior(current, MAP_ENTRY_BEHAV_SEQUENTIAL); + break; + case MADV_RANDOM: + vm_map_entry_set_behavior(current, MAP_ENTRY_BEHAV_RANDOM); + break; + default: + break; + } + vm_map_simplify_entry(map, current); } + vm_map_unlock(map); + } + else { + if (behav == MADV_FREE || behav == MADV_DONTNEED || + behav == MADV_WILLNEED) { + vm_pindex_t pindex; + int count; - vm_map_clip_end(map, current, end); + /* + * madvise behaviors that are implemented in the underlying + * vm_object. + * + * Since we don't clip the vm_map_entry, we have to clip + * the vm_object pindex and count. + */ + for (current = entry; + (current != &map->header) && (current->start < end); + current = current->next) { - switch (advise) { - case MADV_NORMAL: - vm_map_entry_set_behavior(current, MAP_ENTRY_BEHAV_NORMAL); - break; - case MADV_SEQUENTIAL: - vm_map_entry_set_behavior(current, MAP_ENTRY_BEHAV_SEQUENTIAL); - break; - case MADV_RANDOM: - vm_map_entry_set_behavior(current, MAP_ENTRY_BEHAV_RANDOM); - break; - /* - * Right now, we could handle DONTNEED and WILLNEED with common code. - * They are mostly the same, except for the potential async reads (NYI). - */ - case MADV_FREE: - case MADV_DONTNEED: - { - vm_pindex_t pindex; - int count; - pindex = OFF_TO_IDX(current->offset); - count = OFF_TO_IDX(current->end - current->start); - /* - * MADV_DONTNEED removes the page from all - * pmaps, so pmap_remove is not necessary. - */ - vm_object_madvise(current->object.vm_object, - pindex, count, advise); - } - break; + if (current->eflags & MAP_ENTRY_IS_SUB_MAP) + continue; - case MADV_WILLNEED: - { - vm_pindex_t pindex; - int count; pindex = OFF_TO_IDX(current->offset); - count = OFF_TO_IDX(current->end - current->start); + count = atop(current->end - current->start); + + if (current->start < start) { + pindex += atop(start - current->start); + count -= atop(start - current->start); + } + if (current->end > end) + count -= atop(current->end - end); + + if (count <= 0) + continue; + vm_object_madvise(current->object.vm_object, - pindex, count, advise); - pmap_object_init_pt(map->pmap, current->start, - current->object.vm_object, pindex, - (count << PAGE_SHIFT), 0); + pindex, count, behav); + if (behav == MADV_WILLNEED) + pmap_object_init_pt(map->pmap, current->start, + current->object.vm_object, + pindex, (count << PAGE_SHIFT), + 0); } - break; - - default: - break; } + vm_map_unlock_read(map); } - - vm_map_simplify_entry(map, entry); - vm_map_unlock(map); - return; } -- cgit v1.1