Re: [PATCHv6 00/22] Transparent huge page cache: phase 1, everything but mmap()

On Mon, Sep 30, 2013 at 11:02:49AM +0100, Mel Gorman wrote:

On Tue, Sep 24, 2013 at 04:37:40PM -0700, Andrew Morton wrote:

quoted

On Mon, 23 Sep 2013 15:05:28 +0300 "Kirill A. Shutemov" [off-list ref] wrote:

quoted

It brings thp support for ramfs, but without mmap() -- it will be posted
separately.

We were never going to do this :(

Has anyone reviewed these patches much yet?

I am afraid I never looked too closely once I learned that the primary
motivation for this was relieving iTLB pressure in a very specific
case. AFAIK, this is not a problem in the vast majority of modern CPUs
and I found it very hard to be motivated to review the series as a result.
I suspected that in many cases that the cost of IO would continue to dominate
performance instead of TLB pressure. I also found it unlikely that there
was a workload that was tmpfs based that used enough memory to be hurt
by TLB pressure. My feedback was that a much more compelling case for the
series was needed but this discussion all happened on IRC unfortunately.

Oh, one last thing I forgot. While tmpfs-based workloads were not likely to
benefit I would expect that sysV shared memory workloads would potentially
benefit from this.  hugetlbfs is still required for shared memory areas
but it is not a problem that is addressed by this series.

-- 
Mel Gorman
SUSE Labs

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