Policy files contains a classification policy for dmprof.py.

Each line indicates a group to be classified and conditions for classifying
in the following format.
  Format: <group-name> <region-type> <pattern>

<group-name> is a name for the group to be classified.  Same names can appear
in the same policy file multiple times.  <region-type> represents a type of
the memory region.  It's one of {malloc, mmap, default, optional}.  <pattern>
is a Python-style regular expression to match with calling stack frames.

For each memory chunks allocated by malloc, its calling stack frame of malloc
is compared with these classification policies whose <region-type> is 'malloc'
from the top.  If <pattern> of the policy matches the frame, the memory chunk
is classified into <group-name>.  The same way for 'mmap'.

Policy lines whose <region-type>s are 'optional' and 'default' are used by
dmprof.py internally.  'optional' policies can be disabled by removing or
commenting-out.


Guidelines to write a new policy.

Better policies would classify memory on a single layer, or simple combination
of layers.  For example,
- Large-level components (V8, WebKit, ...)
- Mid-level components (Font, FileAPI, ...)
- Low-level libraries (StringImpl, HashTable, ...)
- Mid-level libraries (SharedBuf, XHR, ...)

For example of combinations,
- How about SharedBuf in Font API v.s. other APIs?
- How about Strings in IndexedDB v.s. File APIs?


Deprecated policies for references.

total-vm                       optional        optional
anonymous-vm                   optional        optional
filemapped-vm                  optional        optional
other-vm                       optional        optional
vm-profiler                    optional        optional
vm-total                       optional        optional
mmap-v8-heap-new               mmap    .*v8::.*::ReserveInitialChunk.*
mmap-v8-heap-coderange         mmap    .*v8::.*::CodeRange::Setup.*
mmap-v8-heap-old-evacuate      mmap    .*v8::.*::OldSpace::.* v8::internal::ScavengingVisitor::EvacuateObject.*
mmap-v8-heap-old               mmap    .*v8::.*::OldSpace::.*
mmap-v8-heap-largeobj          mmap    .*v8::.*::LargeObjectChunk::New.*
mmap-v8-heap-other             mmap    .*VirtualMemory.*
mmap-v8-heap-other             mmap    .*v8::internal::OS::Allocate.*
mmap-v8-nonheap                        mmap    .*v8::.*
mmap-webkit                    mmap    .*(WTF::|WebCore::|blink::|WebKit::).*
mmap-sqlite                    mmap    .*sqlite3MemMalloc.*
mmap-pl-arena                  mmap    .*PL_ArenaAllocate.*
mmap-sk                        mmap    .*sk_malloc_flags.*
mmap-total-record-vm           default default