From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jaegeuk Kim Subject: RE: [PATCH 00/16] f2fs: introduce flash-friendly file system Date: Wed, 10 Oct 2012 11:32:48 +0900 Message-ID: <008c01cda68f$8990e140$9cb2a3c0$%kim@samsung.com> References: <50712AAA.5030807@gmail.com> <002201cda46e$88b84d30$9a28e790$%kim@samsung.com> <004101cda52e$72210e20$56632a60$%kim@samsung.com> <004a01cda542$f398e2c0$dacaa840$%kim@samsung.com> <007c01cda60b$43e7fae0$cbb7f0a0$%kim@samsung.com> <008301cda615$ca3b9980$5eb2cc80$%kim@samsung.com> <20121009212012.GO23644@dastard> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: =?utf-8?Q?'Luk=C3=A1=C5=A1_Czerner'?= , 'Namjae Jeon' , 'Vyacheslav Dubeyko' , 'Marco Stornelli' , 'Jaegeuk Kim' , 'Al Viro' , tytso@mit.edu, gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, chur.lee@samsung.com, cm224.lee@samsung.com, jooyoung.hwang@samsung.com, linux-fsdevel@vger.kernel.org To: 'Dave Chinner' Return-path: In-reply-to: <20121009212012.GO23644@dastard> Content-language: ko Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org > -----Original Message----- > From: linux-fsdevel-owner@vger.kernel.org [mailto:linux-fsdevel-owner= @vger.kernel.org] On Behalf Of > Dave Chinner > Sent: Wednesday, October 10, 2012 6:20 AM > To: Jaegeuk Kim > Cc: 'Luk=C3=A1=C5=A1 Czerner'; 'Namjae Jeon'; 'Vyacheslav Dubeyko'; '= Marco Stornelli'; 'Jaegeuk Kim'; 'Al Viro'; > tytso@mit.edu; gregkh@linuxfoundation.org; linux-kernel@vger.kernel.o= rg; chur.lee@samsung.com; > cm224.lee@samsung.com; jooyoung.hwang@samsung.com; linux-fsdevel@vger= =2Ekernel.org > Subject: Re: [PATCH 00/16] f2fs: introduce flash-friendly file system >=20 > [ Folks, can you trim your responses down to just quote the part you > are responding to? Having to repeatedly scroll through 500 lines of > irrelevant text just to find the 5 lines that is being commented on > is exceedingly painful. ] Ok, I'll keep in mind. Thanks. >=20 > On Tue, Oct 09, 2012 at 09:01:18PM +0900, Jaegeuk Kim wrote: > > > From: Luk=C3=A1=C5=A1 Czerner [mailto:lczerner@redhat.com] > > > > > I am sorry but this reply makes me smile. How can you design = a fs > > > > > relying on time attack heuristics to figure out what the prop= er > > > > > layout should be ? Or even endorse such heuristics to be used= in > > > > > mkfs ? What we should be focusing on is to push vendors to ac= tually > > > > > give us such information so we can properly propagate that > > > > > throughout the kernel - that's something everyone will benefi= t from. > > > > > After that the optimization can be done in every file system. > > > > > > > > > > > > > Frankly speaking, I agree that it would be the right direction = eventually. > > > > But, as you know, it's very difficult for all flash vendors to = promote and standardize that. > > > > Because each vendors have different strategies to open their in= ternal information and also try > > > > to protect their secrets whatever they are. > > > > > > > > IMO, we don't need to wait them now. > > > > Instead, from the start, I suggest f2fs that uses those informa= tion to the file system design. > > > > In addition, I suggest using heuristics right now as best effor= ts. >=20 > And in response, other people are "suggesting" that this is the > wrong approach. Ok, it makes sense. I agree that the Linaro survey has been well proceeded, and no more heu= ristic is needed. >=20 > > > > Maybe in future, if vendors give something, f2fs would be more = feasible. > > > > In the mean time, I strongly hope to validate and stabilize f2f= s with community. > > > > > > Do not get me wrong, I do not think it is worth to wait for vendo= rs > > > to come to their senses, but it is worth constantly reminding tha= t > > > we *need* this kind of information and those heuristics are not > > > feasible in the long run anyway. > > > > > > I believe that this conversation happened several times already, = but > > > what about having independent public database of all the internal > > > information about hw from different vendors where users can add > > > information gathered by the time attack heuristic so other does n= ot > > > have to run this again and again. I am not sure if Linaro or some= one > > > else have something like that, someone can maybe post a link to t= hat. >=20 > Linaro already have one, which is another reason why using > heuristics is the wrong approach: >=20 > https://wiki.linaro.org/WorkingGroups/Kernel/Projects/FlashCardSurvey= ?action=3Dshow&redirect=3DWorkingGrou > ps%2FKernelConsolidation%2FProjects%2FFlashCardSurvey >=20 > > As I mentioned, I agree to push vendors to open those information a= ll the time. > > And, I absolutely didn't mean that it is worth to wait vendors. > > I meant, until opening those information by vendors, something like > > proposing f2fs or gathering heuristics are also needed simultaneous= ly. > > > > Anyway, it's very interesting to build a database gathering product= s' information. > > May I access the database? >=20 > It's public information. >=20 > If you want to support different types of flash, then either add > your timing attack derived information on specific hardware to the > above table, or force vendors to update it themselves if they want > their flash memory supported by this filesystem. Sound good. If I also get something, I'll try. Thank you. >=20 > Cheers, >=20 > Dave. > -- > Dave Chinner > david@fromorbit.com > -- > To unsubscribe from this list: send the line "unsubscribe linux-fsdev= el" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html