linux-kernel - Re: [PATCH v5 00/11] Introduce huge zero page

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: <alpine.DEB.2.00.1211141626220.482@chino.kir.corp.google.com>
Date:	Wed, 14 Nov 2012 16:29:06 -0800 (PST)
From:	David Rientjes <rientjes@...gle.com>
To:	Andrew Morton <akpm@...ux-foundation.org>
cc:	"Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
	Andrea Arcangeli <aarcange@...hat.com>, linux-mm@...ck.org,
	Andi Kleen <ak@...ux.intel.com>,
	"H. Peter Anvin" <hpa@...ux.intel.com>,
	linux-kernel@...r.kernel.org,
	"Kirill A. Shutemov" <kirill@...temov.name>
Subject: Re: [PATCH v5 00/11] Introduce huge zero page

On Wed, 14 Nov 2012, Andrew Morton wrote:

> For this reason and for general ease-of-testing: can and should we add
> a knob which will enable users to disable the feature at runtime?  That
> way if it causes problems or if we suspect it's causing problems, we
> can easily verify the theory and offer users a temporary fix.
> 

I think it would be best to add a tunable under 
/sys/kernel/mm/transparent_hugepage and enable it by default whenever 
/sys/kernel/mm/transparent_hugepage/enabled is "always" or "madvise" and 
allocate the huge zero page under such circumstances.  Then we can free it 
if disabled (or if enabled is set to "never") and avoid all the 
refcounting and lazy allocation that causes a regression on Kirill's 
benchmark.
--
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/