linux-kernel - Re: [PATCH 2/3] kvm hypervisor : Add hypercalls to support pv-ticketlock

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: <4D3875AF.1000208@goop.org>
Date:	Thu, 20 Jan 2011 09:49:35 -0800
From:	Jeremy Fitzhardinge <jeremy@...p.org>
To:	vatsa@...ux.vnet.ibm.com
CC:	Peter Zijlstra <peterz@...radead.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Nick Piggin <npiggin@...nel.dk>,
	Mathieu Desnoyers <mathieu.desnoyers@...ymtl.ca>,
	Américo Wang <xiyou.wangcong@...il.com>,
	Eric Dumazet <dada1@...mosbay.com>,
	Jan Beulich <JBeulich@...ell.com>, Avi Kivity <avi@...hat.com>,
	Xen-devel <xen-devel@...ts.xensource.com>,
	"H. Peter Anvin" <hpa@...or.com>,
	Linux Virtualization <virtualization@...ts.linux-foundation.org>,
	Jeremy Fitzhardinge <jeremy.fitzhardinge@...rix.com>,
	kvm@...r.kernel.org, suzuki@...ibm.com
Subject: Re: [PATCH 2/3] kvm hypervisor : Add hypercalls to support pv-ticketlock

On 01/20/2011 03:42 AM, Srivatsa Vaddagiri wrote:
> On Wed, Jan 19, 2011 at 10:53:52AM -0800, Jeremy Fitzhardinge wrote:
>>> The reason for wanting this should be clear I guess, it allows PI.
>> Well, if we can expand the spinlock to include an owner, then all this
>> becomes moot...
> How so? Having an owner will not eliminate the need for pv-ticketlocks
> afaict. We still need a mechanism to reduce latency in scheduling the next
> thread-in-waiting, which is achieved by your patches. 

No, sorry, I should have been clearer.  I meant that going to the effort
of not increasing the lock size to record "in slowpath" state.

    J
--
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/