The Memory Map widget provides a view of linear address space: the range of addresses
currently being used as Private and Shared memory. Unlike other memory monitors, MemMap also shows
you how much address space is Free and could be claimed by either if needed.
Graph
The display is divided into two rows: the lower shows Low memory (addresses below 512MiB) while
the upper is for High memory (addresses above 512MiB). If the "Grid" option is enabled, each row is
divided into 8 boxes. For Low memory, each box always represents 64MiB. For High memory, each box
represents 1/8th of the total. For example, if you have 2048MiB of High memory, each box is 256MiB.
- Private memory (in red) starts on the left side and is always at least 64MiB. If an app
needs more than 64MiB, the system will allocate it from the low end of the Free space. This extra
allocation will NOT be returned to Free space when the app ends. Instead, the system will wait until
it needs more Shared memory but is out of Free space. Only then will it see how much each process is
actually using and adjust the boundary between Private and Free downward.
- Free memory (in gray) lies between Private and Shared and can be reassigned to either
usage. When this gray space disappears, you are out of memory (linear address space, not
physical memory).
- Shared memory (in blue and green) starts at the right side and expands leftward into
the Free space as more is needed. This is where you'll see the most activity. When a block of Shared
memory is freed, it will be returned to Free space if it sits on the boundary between Free and Shared.
Otherwise, MemMap will color it green to indicate that it remains Shared but is currently unused.
(Note: MemMap groups all unused Shared memory into a single green block to show you the total amount
available.)
Numeric Popup
Click on the graph to display its data in numeric form; click on it again to hide the popup.
If desired, you can move the popup elsewhere on the screen by dragging it using either mouse button.
A small 'X' button will appear in the upper right to make it easier to close when you're done.
Properties
Use the Properties dialog to set the colors MemMap uses, and to enable/disable grid lines on the
graph. The grid-line checkbox also identifies how much memory each block represents.