Add vm_map_insert1(9)
The function returns the newly created entry. Use vm_map_insert1() in stack grow code to avoid gap entry re-lookup. The comment update for vm_map_try_merge_entries() was suggested by dougm. Suggested by: alc Reviewed by: alc, markj Tested by: pho Sponsored by: The FreeBSD Foundation MFC after: 1 week Differential revision: https://reviews.freebsd.org/D41099
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@ -1601,19 +1601,16 @@ vm_map_lookup_entry(
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}
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/*
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* vm_map_insert:
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*
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* Inserts the given VM object into the target map at the
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* specified address range.
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*
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* Requires that the map be locked, and leaves it so.
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*
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* If object is non-NULL, ref count must be bumped by caller
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* prior to making call to account for the new entry.
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* vm_map_insert1() is identical to vm_map_insert() except that it
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* returns the newly inserted map entry in '*res'. In case the new
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* entry is coalesced with a neighbor or an existing entry was
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* resized, that entry is returned. In any case, the returned entry
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* covers the specified address range.
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*/
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int
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vm_map_insert(vm_map_t map, vm_object_t object, vm_ooffset_t offset,
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vm_offset_t start, vm_offset_t end, vm_prot_t prot, vm_prot_t max, int cow)
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static int
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vm_map_insert1(vm_map_t map, vm_object_t object, vm_ooffset_t offset,
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vm_offset_t start, vm_offset_t end, vm_prot_t prot, vm_prot_t max, int cow,
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vm_map_entry_t *res)
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{
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vm_map_entry_t new_entry, next_entry, prev_entry;
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struct ucred *cred;
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@ -1760,7 +1757,8 @@ vm_map_insert(vm_map_t map, vm_object_t object, vm_ooffset_t offset,
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map->size += end - prev_entry->end;
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vm_map_entry_resize(map, prev_entry,
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end - prev_entry->end);
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vm_map_try_merge_entries(map, prev_entry, next_entry);
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*res = vm_map_try_merge_entries(map, prev_entry,
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next_entry);
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return (KERN_SUCCESS);
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}
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@ -1821,7 +1819,7 @@ vm_map_insert(vm_map_t map, vm_object_t object, vm_ooffset_t offset,
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* other cases, which are less common.
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*/
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vm_map_try_merge_entries(map, prev_entry, new_entry);
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vm_map_try_merge_entries(map, new_entry, next_entry);
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*res = vm_map_try_merge_entries(map, new_entry, next_entry);
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if ((cow & (MAP_PREFAULT | MAP_PREFAULT_PARTIAL)) != 0) {
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vm_map_pmap_enter(map, start, prot, object, OFF_TO_IDX(offset),
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@ -1831,6 +1829,27 @@ vm_map_insert(vm_map_t map, vm_object_t object, vm_ooffset_t offset,
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return (KERN_SUCCESS);
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}
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/*
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* vm_map_insert:
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*
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* Inserts the given VM object into the target map at the
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* specified address range.
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*
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* Requires that the map be locked, and leaves it so.
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*
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* If object is non-NULL, ref count must be bumped by caller
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* prior to making call to account for the new entry.
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*/
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int
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vm_map_insert(vm_map_t map, vm_object_t object, vm_ooffset_t offset,
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vm_offset_t start, vm_offset_t end, vm_prot_t prot, vm_prot_t max, int cow)
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{
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vm_map_entry_t res;
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return (vm_map_insert1(map, object, offset, start, end, prot, max,
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cow, &res));
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}
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/*
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* vm_map_findspace:
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*
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@ -2318,13 +2337,14 @@ vm_map_merged_neighbor_dispose(vm_map_t map, vm_map_entry_t entry)
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/*
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* vm_map_try_merge_entries:
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*
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* Compare the given map entry to its predecessor, and merge its precessor
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* into it if possible. The entry remains valid, and may be extended.
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* The predecessor may be deleted.
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* Compare two map entries that represent consecutive ranges. If
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* the entries can be merged, expand the range of the second to
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* cover the range of the first and delete the first. Then return
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* the map entry that includes the first range.
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*
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* The map must be locked.
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*/
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void
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vm_map_entry_t
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vm_map_try_merge_entries(vm_map_t map, vm_map_entry_t prev_entry,
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vm_map_entry_t entry)
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{
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@ -2334,7 +2354,9 @@ vm_map_try_merge_entries(vm_map_t map, vm_map_entry_t prev_entry,
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vm_map_mergeable_neighbors(prev_entry, entry)) {
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vm_map_entry_unlink(map, prev_entry, UNLINK_MERGE_NEXT);
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vm_map_merged_neighbor_dispose(map, prev_entry);
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return (entry);
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}
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return (prev_entry);
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}
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/*
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@ -4547,10 +4569,10 @@ vm_map_stack_locked(vm_map_t map, vm_offset_t addrbos, vm_size_t max_ssize,
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gap_bot = top;
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gap_top = addrbos + max_ssize;
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}
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rv = vm_map_insert(map, NULL, 0, bot, top, prot, max, cow);
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rv = vm_map_insert1(map, NULL, 0, bot, top, prot, max, cow,
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&new_entry);
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if (rv != KERN_SUCCESS)
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return (rv);
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new_entry = vm_map_entry_succ(prev_entry);
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KASSERT(new_entry->end == top || new_entry->start == bot,
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("Bad entry start/end for new stack entry"));
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KASSERT((orient & MAP_STACK_GROWS_DOWN) == 0 ||
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@ -4561,10 +4583,17 @@ vm_map_stack_locked(vm_map_t map, vm_offset_t addrbos, vm_size_t max_ssize,
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("new entry lacks MAP_ENTRY_GROWS_UP"));
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if (gap_bot == gap_top)
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return (KERN_SUCCESS);
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rv = vm_map_insert(map, NULL, 0, gap_bot, gap_top, VM_PROT_NONE,
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rv = vm_map_insert1(map, NULL, 0, gap_bot, gap_top, VM_PROT_NONE,
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VM_PROT_NONE, MAP_CREATE_GUARD | (orient == MAP_STACK_GROWS_DOWN ?
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MAP_CREATE_STACK_GAP_DN : MAP_CREATE_STACK_GAP_UP));
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MAP_CREATE_STACK_GAP_DN : MAP_CREATE_STACK_GAP_UP), &gap_entry);
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if (rv == KERN_SUCCESS) {
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KASSERT((gap_entry->eflags & MAP_ENTRY_GUARD) != 0,
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("entry %p not gap %#x", gap_entry, gap_entry->eflags));
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KASSERT((gap_entry->eflags & (MAP_ENTRY_STACK_GAP_DN |
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MAP_ENTRY_STACK_GAP_UP)) != 0,
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("entry %p not stack gap %#x", gap_entry,
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gap_entry->eflags));
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/*
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* Gap can never successfully handle a fault, so
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* read-ahead logic is never used for it. Re-use
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@ -4574,8 +4603,6 @@ vm_map_stack_locked(vm_map_t map, vm_offset_t addrbos, vm_size_t max_ssize,
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* store the original stack protections in the
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* object offset.
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*/
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gap_entry = orient == MAP_STACK_GROWS_DOWN ?
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vm_map_entry_pred(new_entry) : vm_map_entry_succ(new_entry);
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gap_entry->next_read = sgp;
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gap_entry->offset = prot;
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} else {
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@ -526,7 +526,7 @@ vm_map_entry_succ(vm_map_entry_t entry)
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int vm_map_protect(vm_map_t map, vm_offset_t start, vm_offset_t end,
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vm_prot_t new_prot, vm_prot_t new_maxprot, int flags);
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int vm_map_remove (vm_map_t, vm_offset_t, vm_offset_t);
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void vm_map_try_merge_entries(vm_map_t map, vm_map_entry_t prev,
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vm_map_entry_t vm_map_try_merge_entries(vm_map_t map, vm_map_entry_t prev,
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vm_map_entry_t entry);
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void vm_map_startup (void);
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int vm_map_submap (vm_map_t, vm_offset_t, vm_offset_t, vm_map_t);
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