linux-kernel - Re: [RFD] Automatic suspend

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: <200902171557.02149.oliver@neukum.org>
Date:	Tue, 17 Feb 2009 15:56:58 +0100
From:	Oliver Neukum <oliver@...kum.org>
To:	Matthew Garrett <mjg59@...f.ucam.org>
Cc:	Brian Swetland <swetland@...gle.com>,
	"Rafael J. Wysocki" <rjw@...k.pl>,
	Arjan van de Ven <arjan@...radead.org>,
	"Woodruff, Richard" <r-woodruff2@...com>,
	Alan Stern <stern@...land.harvard.edu>,
	Kyle Moffett <kyle@...fetthome.net>,
	Benjamin Herrenschmidt <benh@...nel.crashing.org>,
	pm list <linux-pm@...ts.linux-foundation.org>,
	LKML <linux-kernel@...r.kernel.org>,
	Arve Hjønnevåg <arve@...roid.com>,
	Pavel Machek <pavel@....cz>,
	Nigel Cunningham <nigel@...el.suspend2.net>,
	mark gross <mgross@...ux.intel.com>,
	Uli Luckas <u.luckas@...d.de>,
	Igor Stoppa <igor.stoppa@...ia.com>,
	Len Brown <lenb@...nel.org>
Subject: Re: [RFD] Automatic suspend

Am Tuesday 17 February 2009 15:24:53 schrieb Matthew Garrett:
> On Tue, Feb 17, 2009 at 06:20:01AM -0800, Brian Swetland wrote:
> 
> > Of course that still doesn't address userspace.  Aggressively going to
> > suspend lets us compensate for userspace programs that do somewhat silly
> > things (I agree that it would be best if they didn't but they do and
> > getting *everyone* to write their userspace code to avoid spinning or
> > avoid waking up on short-duration timers to poll is a losing battle).
> 
> Like Pavel pointed out, you could (in principle) handle this by sending 
> a SIGSTOP to everything. The obvious problem with doing so is that this 
> wouldn't result in the processes letting go of the devices, so you 
> wouldn't neccessarily actually get to enter the runtime idle state as a 
> result. Hmm. I'll think about this.

They don't let go of the devices if you suspend either. If you want that
you need active cooperation from user space. In fact if you suspend you
give drivers the guarantee of not getting any output without prior
notification, making their lives easier.

	Regards
		Oliver


--
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/