linux-kernel - Re: Linux 2.6.29

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: <49CAA31B.7080107@garzik.org>
Date:	Wed, 25 Mar 2009 17:33:15 -0400
From:	Jeff Garzik <jeff@...zik.org>
To:	Linus Torvalds <torvalds@...ux-foundation.org>
CC:	Theodore Tso <tytso@....edu>, Ingo Molnar <mingo@...e.hu>,
	Alan Cox <alan@...rguk.ukuu.org.uk>,
	Arjan van de Ven <arjan@...radead.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Nick Piggin <npiggin@...e.de>, David Rees <drees76@...il.com>,
	Jesper Krogh <jesper@...gh.cc>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: Linux 2.6.29

Linus Torvalds wrote:
> OS X, for example, doesn't do the disk barrier. It requires you to do a 
> separate FULL_FSYNC (or something similar) ioctl to get that. Apparently 
> exactly because users don't expect quite _that_ big of a performance hit.

I can understand that, more from an admin standpoint than anything... 
ATA disks' FLUSH CACHE is horribly coarse-grained, all-or-nothing.

SCSI's SYNCHRONIZE CACHE at least gives us an optional (LBA, length) 
pair that can be used to avoid to flushing everything in the cache.

Microsoft has publicly proposed a WRITE BARRIER command for ATA, to try 
and improve the situation:
http://www.t13.org/Documents/UploadedDocuments/docs2007/e07174r0-Write_Barrier_Command_Proposal.doc

but that isn't in the field yet (if ever?)

	Jeff


--
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/