The Heap Report sections of the LEDATA output provide information for each heap segment in the dump. The detailed heap segment reports include information on the free storage tree in the heap segments, the allocated storage elements, and the cause of heap management data structure problems.
Section Number and Heading | Contents |
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[1] Free Storage Tree Report | Within each heap segment, Language Environment keeps
track of unallocated storage areas by chaining them together into
a tree. Each free area represents a node in the tree. Each node contains
a header, which points to its left and right child nodes. The header
also contains the length of each child. The LEDATA HEAP option
formats the free storage tree within each heap, and validates all
node addresses and lengths within each node. Each node address is
validated to ensure that it:
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[2] Heap Segment Map Report | The LEDATA HEAP option produces a report that
lists all of the storage areas within each heap segment, and identifies
the area as either allocated or freed. For each allocated area the
contents of the first X'20 'bytes of the area are displayed
in order to help identify the reason for the storage allocation. Each
allocated storage element has an 8 byte prefix used by Language Environment to manage
the area. The first fullword contains a pointer to the start of the
heap segment. The second fullword contains the length of the allocated
storage element. The formatter validates this header to ensure that
its heap segment pointer is valid. The length is also validated to
ensure that it:
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