From: Paolo Bonzini <pbonzini@redhat.com>
To: Peter Zijlstra <peterz@infradead.org>, Waiman Long <waiman.long@hp.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>,
Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>,
Gleb Natapov <gleb@redhat.com>,
virtualization@lists.linux-foundation.org,
Andi Kleen <andi@firstfloor.org>,
"H. Peter Anvin" <hpa@zytor.com>,
Michel Lespinasse <walken@google.com>,
Thomas Gleixner <tglx@linutronix.de>,
linux-arch@vger.kernel.org, kvm@vger.kernel.org, x86@kernel.org,
Alok Kataria <akataria@vmware.com>,
Ingo Molnar <mingo@redhat.com>,
xen-devel@lists.xenproject.org,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
Rik van Riel <riel@redhat.com>, Arnd Bergmann <arnd@arndb.de>,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
Scott J Norton <scott.norton@hp.com>,
Steven Rostedt <rostedt@goodmis.org>,
Chris Wright <chrisw@sous-sol.org>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
Aswin Chandramouleeswaran <aswin@hp.com>,
Oleg Nesterov <oleg@redhat.com>
Subject: Re: [PATCH v6 05/11] pvqspinlock, x86: Allow unfair spinlock in a PV guest
Date: Tue, 18 Mar 2014 09:16:48 +0100 [thread overview]
Message-ID: <532800F0.10009@redhat.com> (raw)
In-Reply-To: <20140317185447.GM25546@laptop.programming.kicks-ass.net>
Il 17/03/2014 19:54, Peter Zijlstra ha scritto:
> On Mon, Mar 17, 2014 at 01:44:34PM -0400, Waiman Long wrote:
>> The PV ticketlock code was designed to handle lock holder preemption by
>> redirecting CPU resources in a preempted guest to another guest that can
>> better use it and then return the preempted CPU back sooner.
>
> But that's the PV code, not the unfair bit. And your fuller PV thing
> doesn't need the unfair option.
>
I agree. You need three cases:
* non-virt, non-PV: regular qspinlock
* virt (X86_FEATURE_HYPERVISOR), non-PV: test-and-set
* virt, PV: disables test-and-set, adds PV waiting to qspinlock
Paolo
next prev parent reply other threads:[~2014-03-18 8:16 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-03-12 18:54 [PATCH v6 00/11] qspinlock: a 4-byte queue spinlock with PV support Waiman Long
2014-03-12 18:54 ` [PATCH v6 01/11] qspinlock: A generic 4-byte queue spinlock implementation Waiman Long
2014-03-12 18:54 ` [PATCH v6 02/11] qspinlock, x86: Enable x86-64 to use queue spinlock Waiman Long
2014-03-12 18:54 ` [PATCH v6 03/11] qspinlock: More optimized code for smaller NR_CPUS Waiman Long
2014-03-12 18:54 ` [PATCH v6 04/11] qspinlock: Optimized code path for 2 contending tasks Waiman Long
2014-03-12 19:08 ` Waiman Long
2014-03-13 13:57 ` Peter Zijlstra
2014-03-17 17:23 ` Waiman Long
2014-03-12 18:54 ` [PATCH v6 05/11] pvqspinlock, x86: Allow unfair spinlock in a PV guest Waiman Long
2014-03-13 10:54 ` David Vrabel
2014-03-13 13:16 ` Paolo Bonzini
2014-03-17 19:05 ` Konrad Rzeszutek Wilk
2014-03-18 8:14 ` Paolo Bonzini
2014-03-19 3:15 ` Waiman Long
[not found] ` <53290BCD.8010001@hp.com>
2014-03-19 10:07 ` Paolo Bonzini
[not found] ` <53296C6F.7040709@redhat.com>
2014-03-19 16:58 ` Waiman Long
[not found] ` <5329CCAA.9000909@hp.com>
2014-03-19 17:08 ` Paolo Bonzini
2014-03-13 19:03 ` Waiman Long
2014-03-13 15:15 ` Peter Zijlstra
2014-03-13 20:05 ` Waiman Long
2014-03-14 8:30 ` Peter Zijlstra
2014-03-14 8:48 ` Paolo Bonzini
2014-03-17 17:44 ` Waiman Long
2014-03-17 18:54 ` Peter Zijlstra
2014-03-18 8:16 ` Paolo Bonzini [this message]
2014-03-19 3:08 ` Waiman Long
2014-03-17 19:10 ` Konrad Rzeszutek Wilk
2014-03-19 3:11 ` Waiman Long
2014-03-19 15:25 ` Konrad Rzeszutek Wilk
2014-03-12 18:54 ` [PATCH v6 06/11] pvqspinlock, x86: Allow unfair queue spinlock in a KVM guest Waiman Long
2014-03-12 18:54 ` [PATCH v6 07/11] pvqspinlock, x86: Allow unfair queue spinlock in a XEN guest Waiman Long
2014-03-12 18:54 ` [PATCH v6 08/11] pvqspinlock, x86: Rename paravirt_ticketlocks_enabled Waiman Long
2014-03-12 18:54 ` [PATCH RFC v6 09/11] pvqspinlock, x86: Add qspinlock para-virtualization support Waiman Long
2014-03-12 18:54 ` [PATCH RFC v6 10/11] pvqspinlock, x86: Enable qspinlock PV support for KVM Waiman Long
2014-03-12 18:54 ` [PATCH RFC v6 11/11] pvqspinlock, x86: Enable qspinlock PV support for XEN Waiman Long
[not found] ` <1394650498-30118-10-git-send-email-Waiman.Long@hp.com>
2014-03-13 11:21 ` [PATCH RFC v6 09/11] pvqspinlock, x86: Add qspinlock para-virtualization support David Vrabel
2014-03-13 13:57 ` Paolo Bonzini
2014-03-13 19:05 ` Waiman Long
[not found] ` <5321B959.5050305@redhat.com>
2014-03-13 19:49 ` Waiman Long
[not found] ` <53220BBC.4040608@hp.com>
2014-03-14 9:44 ` Paolo Bonzini
[not found] ` <1394650498-30118-11-git-send-email-Waiman.Long@hp.com>
2014-03-13 13:59 ` [PATCH RFC v6 10/11] pvqspinlock, x86: Enable qspinlock PV support for KVM Paolo Bonzini
2014-03-13 19:13 ` Waiman Long
2014-03-14 8:42 ` Paolo Bonzini
2014-03-17 17:47 ` Waiman Long
2014-03-18 8:18 ` Paolo Bonzini
2014-03-13 15:25 ` Peter Zijlstra
2014-03-13 20:09 ` Waiman Long
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=532800F0.10009@redhat.com \
--to=pbonzini@redhat.com \
--cc=akataria@vmware.com \
--cc=andi@firstfloor.org \
--cc=arnd@arndb.de \
--cc=aswin@hp.com \
--cc=boris.ostrovsky@oracle.com \
--cc=chrisw@sous-sol.org \
--cc=gleb@redhat.com \
--cc=hpa@zytor.com \
--cc=jeremy@goop.org \
--cc=konrad.wilk@oracle.com \
--cc=kvm@vger.kernel.org \
--cc=linux-arch@vger.kernel.org \
--cc=mingo@redhat.com \
--cc=oleg@redhat.com \
--cc=paulmck@linux.vnet.ibm.com \
--cc=peterz@infradead.org \
--cc=raghavendra.kt@linux.vnet.ibm.com \
--cc=riel@redhat.com \
--cc=rostedt@goodmis.org \
--cc=scott.norton@hp.com \
--cc=tglx@linutronix.de \
--cc=virtualization@lists.linux-foundation.org \
--cc=waiman.long@hp.com \
--cc=walken@google.com \
--cc=x86@kernel.org \
--cc=xen-devel@lists.xenproject.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).