From mboxrd@z Thu Jan 1 00:00:00 1970 From: Xiao Guangrong Subject: Re: Documentation of the kvm->srcu lock Date: Mon, 09 Sep 2013 20:26:49 +0800 Message-ID: <522DBE89.1060505@linux.vnet.ibm.com> References: <20130909140032.3fb22a4a@thhw500> <522DBB6D.1050206@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Cc: Thomas Huth , kvm@vger.kernel.org To: Paolo Bonzini Return-path: Received: from e23smtp03.au.ibm.com ([202.81.31.145]:58797 "EHLO e23smtp03.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751591Ab3IIM06 (ORCPT ); Mon, 9 Sep 2013 08:26:58 -0400 Received: from /spool/local by e23smtp03.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Mon, 9 Sep 2013 22:15:22 +1000 Received: from d23relay04.au.ibm.com (d23relay04.au.ibm.com [9.190.234.120]) by d23dlp03.au.ibm.com (Postfix) with ESMTP id C44D43578050 for ; Mon, 9 Sep 2013 22:26:52 +1000 (EST) Received: from d23av01.au.ibm.com (d23av01.au.ibm.com [9.190.234.96]) by d23relay04.au.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id r89CAWgP7864802 for ; Mon, 9 Sep 2013 22:10:32 +1000 Received: from d23av01.au.ibm.com (localhost [127.0.0.1]) by d23av01.au.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id r89CQpDk023951 for ; Mon, 9 Sep 2013 22:26:52 +1000 In-Reply-To: <522DBB6D.1050206@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: On 09/09/2013 08:13 PM, Paolo Bonzini wrote: > Il 09/09/2013 14:00, Thomas Huth ha scritto: >> >> Hi all! >> >> I am quite new to KVM, and I recently had to struggle with the >> kvm->srcu lock a little bit ... documentation for this lock seems >> to be quite sparse, I've only found some descriptions in mailing >> list archives (the description at the following URL is quite good: >> http://www.mail-archive.com/kvm@vger.kernel.org/msg90003.html ). >> >> So I wonder whether it would be helpful for others, too, if some >> information about this lock was added to the documentation file >> Documentation/virtual/kvm/locking.txt for example? I'd like to >> suggest the following text as a first draft (using some information >> from the URL above): >> >> Name: kvm->srcu >> Type: srcu lock >> Arch: any >> Protects: - kvm->memslots >> - kvm->buses >> Comment: The srcu read lock must be held while accessing memslots (e.g. >> when using gfn_to_* functions) and while accessing in-kernel >> MMIO/PIO address->device structure mapping (kvm->buses). >> The srcu index can be stored in kvm_vcpu->srcu_idx per vcpu >> if it is needed by multiple functions. >> >> What do you think? Since I am not an expert in this area, extension >> and/or corrections are very welcome! > > Yes, this looks good. Xiao, any suggestions? It's nice indeed! :) Reviewed-by: Xiao Guangrong