1.4.1 Temporary Buffers and Zone Entries

ExAllocatePool: Allocates (optionally cache-aligned) memory from paged or nonpaged system space.
ExAllocatePoolWithQuota: Allocates pool memory charging quota against the original requestor of the I/O operation. (Only highest-level drivers can call this routine.)
ExAllocatePoolWithTag: Allocates (optionally cache-aligned) tagged memory from paged or nonpaged system space. The caller-supplied tag is put into any crash dump of memory that occurs.
ExAllocatePoolWithQuotaTag: Allocates tagged pool memory charging quota against the original requestor of the I/O operation. The caller-supplied tag is put into any crash dump of memory that occurs. (Only highest-level drivers can call this routine.)
ExFreePool: Releases memory to paged or nonpaged system space.
ExInitializeNPagedLookasideList: Initializes a lookaside list of nonpaged memory. After a successful initialization, fixed-size blocks can be allocated from and freed to the lookaside list.
ExAllocateFromNPagedLookasideList: Removes the first entry from the specified lookaside list in nonpaged memory. If the lookaside list is empty, an entry is allocated from nonpaged pool.
ExFreeToNPagedLookasideList: Returns an entry to the specified lookaside list in nonpaged memory. If the list has reached its maximum size, the entry is returned to nonpaged pool.
ExDeleteNPagedLookasideList: Deletes a nonpaged lookaside list.
ExInitializePagedLookasideList: Initializes a lookaside list of paged memory. After a successful initialization, fixed-size blocks can be allocated from and freed to the lookaside list.
ExAllocateFromPagedLookasideList: Removes the first entry from the specified lookaside list in paged memory. If the lookaside list is empty, an entry is allocated from paged pool.
ExFreeToPagedLookasideList: Returns an entry to the specified lookaside list in paged memory. If the list has reached its maximum size, the entry is returned to paged pool.
ExDeletePagedLookasideList: Deletes a paged lookaside list.
ExInitializeZone: Initializes a zone buffer header, setting up the fixed size for every block to be allocated from the zone.
ExAllocateFromZone: Allocates a fixed-size block of storage from a zone buffer.
ExFreeToZone: Returns a previously allocated, fixed-size block in a zone buffer to the zone’s free-block list.
ExIsFullZone: Determines whether all fixed-size blocks have been allocated from a given zone buffer.
ExInterlockedAllocateFromZone: Allocates a fixed-size block from a zone buffer, using a spin lock to ensure multiprocessor-safe access to the zone’s free-block list.
ExInterlockedFreeToZone: Releases a fixed-size block in a zone buffer, using a spin lock to ensure multiprocessor-safe access to the zone’s free-block list.
ExExtendZone: Extends an existing zone buffer by allocating a block-size-granular amount of additional memory, which cannot be released until the machine is rebooted.
ExInterlockedExtendZone: Extends an existing zone buffer, which cannot be released until the machine is rebooted, using a spin lock to ensure multiprocessor-safe access to the zone header.
ExIsObjectInFirstZoneSegment: Returns whether a given entry was allocated from the original zone segment or from an extension to the zone.
MmQuerySystemSize: Returns whether the machine has a small, medium, or large amount of available memory.
MmIsThisAnNtAsSystem: Returns whether the machine is running as a server or as a desktop client. If this routine returns TRUE, the caller is likely to require more resources to process I/O requests, and the machine is a server so it is likely to have more resources available.