linux-kernel - RE: Frontswap [PATCH 0/4] (was Transcendent Memory): overview

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: <53c81c97-b30f-4081-91a1-7cef1879c6fa@default>
Date:	Thu, 22 Apr 2010 08:48:31 -0700 (PDT)
From:	Dan Magenheimer <dan.magenheimer@...cle.com>
To:	Avi Kivity <avi@...hat.com>
Cc:	linux-kernel@...r.kernel.org, linux-mm@...ck.org, jeremy@...p.org,
	hugh.dickins@...cali.co.uk, ngupta@...are.org, JBeulich@...ell.com,
	chris.mason@...cle.com, kurt.hackel@...cle.com,
	dave.mccracken@...cle.com, npiggin@...e.de,
	akpm@...ux-foundation.org, riel@...hat.com
Subject: RE: Frontswap [PATCH 0/4] (was Transcendent Memory): overview

> > a synchronous concurrency-safe page-oriented pseudo-RAM device (such
> >  :
> > conform to certain policies as follows:
> 
> How baked in is the synchronous requirement?  Memory, for example, can
> be asynchronous if it is copied by a dma engine, and since there are
> hardware encryption engines, there may be hardware compression engines
> in the future.

Thanks for the comment!

Synchronous is required, but likely could be simulated by ensuring all
coherency (and concurrency) requirements are met by some intermediate
"buffering driver" -- at the cost of an extra page copy into a buffer
and overhead of tracking the handles (poolid/inode/index) of pages in
the buffer that are "in flight".  This is an approach we are considering
to implement an SSD backend, but hasn't been tested yet so, ahem, the
proof will be in the put'ing. ;-)

Dan
--
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/