Re: + per-cpuset-hugetlb-accounting-and-administration.patch added to -mm tree

[Bill Irwin <bill.irwin@oracle.com>]

On Thu, May 03, 2007 at 06:38:21PM -0700, Paul Jackson wrote:
> Adding Christoph Lameter <clameter@sgi.com> to the cc list, as he knows
> more about hugetlb pages than I do.
> This patch strikes me as a bit odd.
> Granted, it's solving what could be a touchy problem with a fairly
> simple solution, which is usually a Good Thing(tm).
> However, the idea that different tasks would see different values for
> the following fields in /proc/meminfo:
> 	HugePages_Total:     0
> 	HugePages_Free:      0
> strikes me as odd, and risky.  I would have thought that usually, all
> tasks in the system should see the same values in the files in /proc
> (as opposed to the files in particular task subdirectories /proc/<pid>.)
> This patch strikes me as a bit of a hack, good for compatibility, but
> hiding a booby trap that will bite some user code in the long run.
> But I'm not enough of an expert to know what the right tradeoffs are
> in this matter.

The semantics of the global /proc/meminfo should not change; a separate
per-cpuset reporting mechanism should really be used.


-- wli