From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e19.ny.us.ibm.com (e19.ny.us.ibm.com [129.33.205.209]) (using TLSv1 with cipher CAMELLIA256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id A4F9B1A060B for ; Sat, 31 Oct 2015 09:13:32 +1100 (AEDT) Received: from localhost by e19.ny.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Fri, 30 Oct 2015 18:13:30 -0400 Received: from b01cxnp22036.gho.pok.ibm.com (b01cxnp22036.gho.pok.ibm.com [9.57.198.26]) by d01dlp03.pok.ibm.com (Postfix) with ESMTP id D0168C90048 for ; Fri, 30 Oct 2015 18:01:37 -0400 (EDT) Received: from d01av01.pok.ibm.com (d01av01.pok.ibm.com [9.56.224.215]) by b01cxnp22036.gho.pok.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id t9UMDQtk50135144 for ; Fri, 30 Oct 2015 22:13:26 GMT Received: from d01av01.pok.ibm.com (localhost [127.0.0.1]) by d01av01.pok.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id t9UMDPTR020974 for ; Fri, 30 Oct 2015 18:13:26 -0400 Date: Fri, 30 Oct 2015 15:13:24 -0700 From: Nishanth Aravamudan To: Keith Busch Cc: aik@ozlabs.ru, linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org, Christoph Hellwig , paulus@samba.org, sparclinux@vger.kernel.org, willy@linux.intel.com, linuxppc-dev@lists.ozlabs.org, David Miller , david@gibson.dropbear.id.au Subject: Re: [PATCH 1/1 v3] drivers/nvme: default to 4k device page size Message-ID: <20151030221324.GM7716@linux.vnet.ibm.com> References: <20151026.182746.1323901353520152838.davem@davemloft.net> <20151027222010.GD7716@linux.vnet.ibm.com> <20151027223643.GA25332@localhost.localdomain> <20151027.175443.140992924519172506.davem@davemloft.net> <20151028135922.GA27909@localhost.localdomain> <20151029115536.GA28090@infradead.org> <20151029155701.GJ7716@linux.vnet.ibm.com> <20151029172043.GA8343@localhost.localdomain> <20151030213511.GK7716@linux.vnet.ibm.com> <20151030214848.GC13904@localhost.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20151030214848.GC13904@localhost.localdomain> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On 30.10.2015 [21:48:48 +0000], Keith Busch wrote: > On Fri, Oct 30, 2015 at 02:35:11PM -0700, Nishanth Aravamudan wrote: > > Given that it's 4K just about everywhere by default (and sort of > > implicitly expected to be, I guess), I think I'd prefer we default to > > 4K. That should mitigate the performance impact (I'll ask our IO team to > > do some runs, but since this impacts functionality on some hardware, I > > don't think it's too relevant for now). Unless there are NVMe devcies > > with a MPSMAX < 4K? > > Right, I assumed MPSMIN was always 4k for the same reason you mentioned, > but you can hard code it like you've done in your patch. > > The spec defines MPSMAX such that it's impossible to find a device > with MPSMAX < 4k. Great, thanks! -Nish