Pzone based CKRM memory resource controller

(Changed the mail format into LKML-style and added linux-mm list to Cc:.
These patches are almost the same as what I sent to [email protected] this week.)

The pzone (pseudo zone) based memory resource controller is yet another implementation of the CKRM memory resource controller. The existing CKRM memory resource controller counts the number of pages that are allocated for tasks in a class in order to guarantee and limit memory resources. This requires changes to the existing code for page allocation and page reclaim.

This memory resource controller takes a different approach aiming at less impact to the existing Linux kernel code. The pzone is introduced to reserve the specified number of pages from the existing zone. The pzone uses the existing zone structure but adds several members. This enables us smaller impact to the memory management code; our memory resource controller doesn't require special LRU lists of pages or addition of a member to the page structure. Also, it doesn't require any changes for the algorithms in the memory management system.

Tasks in a class allocate pages using the zonelist that consists of pzones. The memory resource guarantee is achieved by preventing tasks in other classes from allocating pages from the pzones. The number of pages that a class holds can be achieved by limiting page allocations only from the pzones and disabling page allocations from conventional zones.

Thus, pages are accounted for the class of tasks that call __alloc_pages(). Resource guarantee and limit are handled as the same value. User-space daemons could be introduced in order to separate guarantee and limit.

The current implementation doesn't move resource account when the class of a task is changed. Moving resource account could be implemented by using Christoph Lameter's page migration patches.

The patches are against linux-2.6.15, the first patch is for introducing pzones and the second is for implementing memory resource controller using pzones. These patches are not adequately tested yet. They are still under development and need further work.

Regards,

KUROSAWA, Takahiro

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to [email protected]. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"[email protected]"> [email protected] </a>