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Various changes to vm_object_shadow(): (1) update the vm_object locking,
(2) remove a pointless assertion, and (3) make a trivial change to a comment.
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parent
32660658b8
commit
570a2f4ac5
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=114112
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@ -1078,26 +1078,29 @@ vm_object_shadow(
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vm_object_t source;
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vm_object_t result;
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GIANT_REQUIRED;
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source = *object;
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vm_object_lock(source);
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/*
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* Don't create the new object if the old object isn't shared.
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*/
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if (source != NULL &&
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source->ref_count == 1 &&
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source->handle == NULL &&
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(source->type == OBJT_DEFAULT ||
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source->type == OBJT_SWAP)) {
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vm_object_unlock(source);
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return;
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if (source != NULL) {
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VM_OBJECT_LOCK(source);
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if (source->ref_count == 1 &&
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source->handle == NULL &&
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(source->type == OBJT_DEFAULT ||
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source->type == OBJT_SWAP)) {
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VM_OBJECT_UNLOCK(source);
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return;
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}
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VM_OBJECT_UNLOCK(source);
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}
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/*
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* Allocate a new object with the given length
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* Allocate a new object with the given length.
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*/
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result = vm_object_allocate(OBJT_DEFAULT, length);
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KASSERT(result != NULL, ("vm_object_shadow: no object for shadowing"));
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/*
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* The new object shadows the source object, adding a reference to it.
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@ -1110,7 +1113,8 @@ vm_object_shadow(
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* shadowed object.
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*/
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result->backing_object = source;
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if (source) {
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if (source != NULL) {
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VM_OBJECT_LOCK(source);
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TAILQ_INSERT_TAIL(&source->shadow_head, result, shadow_list);
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source->shadow_count++;
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source->generation++;
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@ -1121,6 +1125,7 @@ vm_object_shadow(
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length = PQ_L2_SIZE / 3 + PQ_PRIME1;
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result->pg_color = (source->pg_color +
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length * source->generation) & PQ_L2_MASK;
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VM_OBJECT_UNLOCK(source);
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next_index = (result->pg_color + PQ_L2_SIZE / 3 + PQ_PRIME1) &
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PQ_L2_MASK;
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}
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@ -1136,8 +1141,6 @@ vm_object_shadow(
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*/
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*offset = 0;
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*object = result;
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vm_object_unlock(source);
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}
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/*
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