tree 75e802f07a8c4f0554547e8dd795f544c7e9d7e8
parent 4c887265977213985091476be40ab11dfdcb4caf
author Adam Litke <agl@us.ibm.com> 1130635007 -0700
committer Linus Torvalds <torvalds@g5.osdl.org> 1130647243 -0700

[PATCH] hugetlb: overcommit accounting check

Basic overcommit checking for hugetlb_file_map() based on an implementation
used with demand faulting in SLES9.

Since demand faulting can't guarantee the availability of pages at mmap
time, this patch implements a basic sanity check to ensure that the number
of huge pages required to satisfy the mmap are currently available.
Despite the obvious race, I think it is a good start on doing proper
accounting.  I'd like to work towards an accounting system that mimics the
semantics of normal pages (especially for the MAP_PRIVATE/COW case).  That
work is underway and builds on what this patch starts.

Huge page shared memory segments are simpler and still maintain their
commit on shmget semantics.

Signed-off-by: Adam Litke <agl@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>