MI_PARTITION

As a feature of the Memory Manager, a memory partition is represented by the MI_PARTITION structure (formally _MI_PARTITION). Exposed through the Object Manager, a partition object is a pointer to an MI_PARTITION.

Memory partitions are new for Windows 10. They are in effect specific to 64-bit Windows, since 32-bit Windows has just the one system partition. Each partition is in some sense a separate instance of what earlier versions treat as the whole management of physical memory. Among the side-effects is that most of the relevant internal variables which used to show plainly when debugging with public symbols now show less plainly because they are members of members of an MI_PARTITION structure, which anyway may be found only through members of members of the MI_SYSTEM_INFORMATION structure which is the type of the internal variable named MiState.

Variability

The MI_PARTITION structure is unsurprisingly treated as if it is no less internal than when many of its members were internal variables. It is highly susceptible to changing between builds. Its changes of size give some rough indication:

It happens, however, that all change from one build to the next is in the many substructures, not in the direct members, until an insertion for Version 1903.

Layout

The sizes in the preceding table and the offsets, names and types in the next are from type information in public symbol files for the kernel.

MI_PARTITION_CORE Core;

MI_PARTITION_MODWRITES Modwriter;

MI_PARTITION_STORES Store;

MI_PARTITION_SEGMENTS Segments;

MI_PARTITION_PAGE_LISTS PageLists;

MI_PARTITION_COMMIT Commit;

MI_PARTITION_ZEROING Zeroing;

MI_PAGE_COMBINING_SUPPORT PageCombine;

PVOID WorkingSetControl;

MM_WORKING_SET_EXPANSION_HEAD WorkingSetExpansionHead;

ULONG SessionDetachTimeStamp;

MI_VISIBLE_PARTITION Vp;