From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marcelo Tosatti Subject: Re: [PATCH] KVM: Start lock documentation Date: Tue, 15 Feb 2011 14:44:14 -0200 Message-ID: <20110215164414.GA12410@amt.cnet> References: <4D52A090.5010308@siemens.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Avi Kivity , kvm To: Jan Kiszka Return-path: Received: from mx1.redhat.com ([209.132.183.28]:43695 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751952Ab1BORBk (ORCPT ); Tue, 15 Feb 2011 12:01:40 -0500 Content-Disposition: inline In-Reply-To: <4D52A090.5010308@siemens.com> Sender: kvm-owner@vger.kernel.org List-ID: On Wed, Feb 09, 2011 at 03:11:28PM +0100, Jan Kiszka wrote: > The goal of this document shall be > - overview of all locks used in KVM core > - provide details on the scope of each lock > - explain the lock type, specifically of a raw spin locks > - provide a lock ordering guide > > Start with one dependency chain and two locks. > > Signed-off-by: Jan Kiszka > --- > Documentation/kvm/locking.txt | 30 ++++++++++++++++++++++++++++++ > 1 files changed, 30 insertions(+), 0 deletions(-) > create mode 100644 Documentation/kvm/locking.txt > > diff --git a/Documentation/kvm/locking.txt b/Documentation/kvm/locking.txt > new file mode 100644 > index 0000000..23f9092 > --- /dev/null > +++ b/Documentation/kvm/locking.txt > @@ -0,0 +1,30 @@ > +KVM Lock Overview > +================= > + > +1. Acquisition Orders > +--------------------- > + > +kvm_lock > ++-> kvm::srcu / kvm::lock > + +-> kvm::slots_lock > + +-> kvm::mmu_lock > +... Its not easy to understand what you mean here. What kvm_lock has to do with the ordering described below it? Other than that, "Reference" section structure is fine... (yeah, Avi has been asking it for ages). > + > +2. Reference > +------------ > + > +Name: kvm_lock > +Type: raw_spinlock > +Arch: any > +Protects: - vm_list > + - hardware virtualization enable/disable > +Comment: 'raw' because hardware enabling/disabling must be atomic /wrt > + migration. > + > +Name: kvm_arch::tsc_write_lock > +Type: raw_spinlock > +Arch: x86 > +Protects: - kvm_arch::{last_tsc_write,last_tsc_nsec,last_tsc_offset} > + - tsc offset in vmcb > +Comment: 'raw' because updating the tsc offsets must not be preempted. > -- > 1.7.1 > -- > To unsubscribe from this list: send the line "unsubscribe kvm" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html