From mboxrd@z Thu Jan 1 00:00:00 1970 From: Konrad Rzeszutek Wilk Subject: Re: [PATCH] blkif.h: enhance comments related to the discard feature Date: Wed, 22 Jan 2014 16:14:49 -0500 Message-ID: <20140122211449.GA10426@phenom.dumpdata.com> References: <1389736679-15637-1-git-send-email-olaf@aepfle.de> <52D955A902000078001149E2@nat28.tlf.novell.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mail6.bemta4.messagelabs.com ([85.158.143.247]) by lists.xen.org with esmtp (Exim 4.72) (envelope-from ) id 1W658V-00022Y-Th for xen-devel@lists.xenproject.org; Wed, 22 Jan 2014 21:15:00 +0000 Content-Disposition: inline In-Reply-To: <52D955A902000078001149E2@nat28.tlf.novell.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Jan Beulich Cc: xen-devel , Olaf Hering , Keir Fraser List-Id: xen-devel@lists.xenproject.org On Fri, Jan 17, 2014 at 03:09:13PM +0000, Jan Beulich wrote: > >>> On 14.01.14 at 22:57, Olaf Hering wrote: > > Also fix the name of the discard-alignment property, add the missing 'n'. > > > > Signed-off-by: Olaf Hering > > Konrad, > > you have been working on the discard stuff quite a bit iirc - any > chance you could take a look and send and ack/review? > > Jan > > > --- > > xen/include/public/io/blkif.h | 16 ++++++++++++---- > > 1 file changed, 12 insertions(+), 4 deletions(-) > > > > diff --git a/xen/include/public/io/blkif.h b/xen/include/public/io/blkif.h > > index 84eb7fd..515ea90 100644 > > --- a/xen/include/public/io/blkif.h > > +++ b/xen/include/public/io/blkif.h > > @@ -175,7 +175,7 @@ > > * > > *------------------------- Backend Device Properties ------------------------- > > * > > - * discard-aligment > > + * discard-alignment > > * Values: > > * Default Value: 0 > > * Notes: 4, 5 > > @@ -194,6 +194,7 @@ > > * discard-secure > > * Values: 0/1 (boolean) > > * Default Value: 0 > > + * Notes: 10 > > * > > * A value of "1" indicates that the backend can process > > BLKIF_OP_DISCARD > > * requests with the BLKIF_DISCARD_SECURE flag set. > > @@ -323,9 +324,14 @@ > > * For full interoperability, block front and backends should publish > > * identical ring parameters, adjusted for unit differences, to the > > * XenStore nodes used in both schemes. > > - * (4) Devices that support discard functionality may internally allocate > > - * space (discardable extents) in units that are larger than the > > - * exported logical block size. > > + * (4) Devices that support discard functionality may internally allocate > > space > > + * (discardable extents) in units that are larger than the exported > > logical > > + * block size. If the backing device has such discardable extents the > > + * backend must provide both discard-granularity and discard-alignment. ^^^^ - MAY > > + * Backends supporting discard should include discard-granularity and ^^^^^ - MAY > > + * discard-alignment even if it supports discarding individual sectors. > > + * Frontends should assume discard-alignment == 0 and discard-granularity > > == > > + * sector size if these keys are missing. > > * (5) The discard-alignment parameter allows a physical device to be > > * partitioned into virtual devices that do not necessarily begin or > > * end on a discardable extent boundary. > > @@ -344,6 +350,8 @@ > > * grants that can be persistently mapped in the frontend driver, but > > * due to the frontent driver implementation it should never be bigger > > * than RING_SIZE * BLKIF_MAX_SEGMENTS_PER_REQUEST. > > + *(10) The discard-secure property may be present and will be set to 1 if > > the > > + * backing device supports secure discard. > > */ > > > > /* > > > > _______________________________________________ > > Xen-devel mailing list > > Xen-devel@lists.xen.org > > http://lists.xen.org/xen-devel > > >