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

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20130930101029.GC2425@suse.de>
Date:	Mon, 30 Sep 2013 11:10:29 +0100
From:	Mel Gorman <mgorman@...e.de>
To:	Andrew Morton <akpm@...ux-foundation.org>
Cc:	"Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
	Andrea Arcangeli <aarcange@...hat.com>,
	Al Viro <viro@...iv.linux.org.uk>,
	Hugh Dickins <hughd@...gle.com>,
	Wu Fengguang <fengguang.wu@...el.com>, Jan Kara <jack@...e.cz>,
	linux-mm@...ck.org, Andi Kleen <ak@...ux.intel.com>,
	Matthew Wilcox <willy@...ux.intel.com>,
	"Kirill A. Shutemov" <kirill@...temov.name>,
	Hillf Danton <dhillf@...il.com>, Dave Hansen <dave@...1.net>,
	Ning Qu <quning@...gle.com>,
	Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
	linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: 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:
> > On Mon, 23 Sep 2013 15:05:28 +0300 "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com> wrote:
> > 
> > > 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 from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/