From: Ted Ts'o Subject: Re: [PATCH 2/3] ext4: Context support Date: Tue, 12 Jun 2012 16:41:28 -0400 Message-ID: <20120612204128.GF12161@thunk.org> References: <1339411562-17100-1-git-send-email-saugata.das@stericsson.com> <201206121455.50639.arnd.bergmann@linaro.org> <20120612181958.GB1803@thunk.org> <201206122007.28514.arnd.bergmann@linaro.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Saugata Das , Artem Bityutskiy , Saugata Das , linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mmc@vger.kernel.org, patches@linaro.org, venkat@linaro.org To: Arnd Bergmann Return-path: Content-Disposition: inline In-Reply-To: <201206122007.28514.arnd.bergmann@linaro.org> Sender: linux-fsdevel-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org On Tue, Jun 12, 2012 at 08:07:28PM +0000, Arnd Bergmann wrote: > Right. The danger here is that the context support was described in > the standard first, while none of the devices seem to even be > smart enough to make use of the information we put in there. Once > operating systems start putting some data in there, at least > some manufacturers will start making use of that data to optimize > the accesses, but it's very unlikely that they will tell us exactly > what they are doing. Having code in ext4 that uses the contexts will > at least make it more likely that the firmware optimizations are > based on ext4 measurements rather than some other file system or > operating system. > > From talking with the emmc device vendors, I can tell you that ext4 > is very high on the list of file systems to optimize for, because > they all target Android products. Well, I have a contact at SanDisk where I can discuss things under NDA, if that will help. He had reached out to me specifically because of ext4 and Android --- he's the guy that I invited to give a talk at the LSF workshop last year. - Ted