Fix a bug related to sbrk() calls that could cause address space leaks.

This is a long-standing bug, but until recent changes it was difficult
to trigger, and even then its impact was non-catastrophic, with the
exception of revision 1.157.

Optimize chunk_alloc_mmap() to avoid the need for unmapping pages in the
common case.  Thanks go to Kris Kennaway for a patch that inspired this
change.

Do not maintain a record of previously mmap'ed chunk address ranges.
The original intent was to avoid the extra system call overhead in
chunk_alloc_mmap(), which is no longer a concern.  This also allows some
simplifications for the tree of unused DSS chunks.

Introduce huge_mtx and dss_chunks_mtx to replace chunks_mtx.  There was
no compelling reason to use the same mutex for these disjoint purposes.

Avoid memset() for huge allocations when possible.

Maintain two trees instead of one for tracking unused DSS address
ranges.  This allows scalable allocation of multi-chunk huge objects in
the DSS.  Previously, multi-chunk huge allocation requests failed if the
DSS could not be extended.

0 files changed, 0 insertions, 0 deletions