From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:57792) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fi4XE-0003ay-QK for qemu-devel@nongnu.org; Tue, 24 Jul 2018 17:07:57 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fi4XD-00049Q-MW for qemu-devel@nongnu.org; Tue, 24 Jul 2018 17:07:56 -0400 References: <20180724200343.13733-1-lbloch@janustech.com> <20180724200343.13733-3-lbloch@janustech.com> From: Eric Blake Message-ID: Date: Tue, 24 Jul 2018 16:07:48 -0500 MIME-Version: 1.0 In-Reply-To: <20180724200343.13733-3-lbloch@janustech.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v3 2/5 for-3.0] qcow2: Options' documentation fixes List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Leonid Bloch , qemu-devel@nongnu.org Cc: qemu-block@nongnu.org, Kevin Wolf , Max Reitz , Alberto Garcia On 07/24/2018 03:03 PM, Leonid Bloch wrote: > Signed-off-by: Leonid Bloch > --- > docs/qcow2-cache.txt | 3 +++ > qemu-options.hx | 15 +++++++++++---- > 2 files changed, 14 insertions(+), 4 deletions(-) > > diff --git a/docs/qcow2-cache.txt b/docs/qcow2-cache.txt > index 8a09a5cc5f..9d261b7da9 100644 > --- a/docs/qcow2-cache.txt > +++ b/docs/qcow2-cache.txt > @@ -130,6 +130,9 @@ There are a few things that need to be taken into account: > memory as possible to the L2 cache before increasing the refcount > cache size. > > +- All three "l2-cache-size", "refcount-cache-size", and "cache-size" options > + can not be set simultaneously. Reads awkwardly; maybe: At most two of "l2-cache-size", "refcount-cache-size", and "cache-size" can be set together on the command line (the omitted options are calculated accordingly). > +++ b/qemu-options.hx > @@ -752,15 +752,22 @@ image file) > > @item cache-size > The maximum total size of the L2 table and refcount block caches in bytes > -(default: 1048576 bytes or 8 clusters, whichever is larger) > > @item l2-cache-size > -The maximum size of the L2 table cache in bytes > -(default: 4/5 of the total cache size) > +The maximum size of the L2 table cache. > +(default: if cache-size is not defined - 1048576 bytes or 8 clusters, > +whichever is larger; if cache-size is defined and is large enough to > +accommodate enough L2 cache to cover the entire virtual size of the image plus > +the minimal amount of refcount cache - enough to cover the entire image; > +if cache-size is defined and is not large enough - as much as possible while > +leaving space for the needed refcount cache) Wordy; maybe: (default: if cache-size is not defined - 1048576 bytes or 8 clusters, whichever is larger; otherwise, as large as possible within cache-size while still permitting the requested or minimum refcount cache size). > > @item refcount-cache-size > The maximum size of the refcount block cache in bytes > -(default: 1/5 of the total cache size) > +(default: 4 times the cluster size, or if cache-size is defined and is large > +enough to accommodate enough L2 cache to cover the entire virtual size of the > +image plus the minimal amount of refcount cache - the part of cache-size which > +is left after allocating the full L2 cache) Maybe: (default: 4 times the cluster size, plus any portion of a specified cache-size left over after sizing the L2 cache large enough to cover the entire image) -- Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3266 Virtualization: qemu.org | libvirt.org