Hi All, > -----Original Message----- > From: [email protected] [mailto:[email protected]] > On Behalf Of Arnd Bergmann > Sent: Tuesday, April 10, 2012 1:40 AM > To: Minchan Kim > Cc: 정효진; 'Alex Lemberg'; [email protected]; 'Rik van Riel'; > [email protected]; [email protected]; Luca Porzio > (lporzio); [email protected]; [email protected]; 'Yejin Moon'; 'Hugh > Dickins'; 'Yaniv Iarovici'; [email protected] > Subject: Re: swap on eMMC and other flash > > On Tuesday 10 April 2012, Minchan Kim wrote: > > I think it's not good approach. > > How long does it take to know such parameters? > > I guess it's not short so that mkfs/mkswap would be very long > > dramatically. If needed, let's maintain it as another tool. > > I haven't come up with a way that is both fast and reliable. > A very fast method is to time short read requests across potential > erase block boundaries and see which ones are faster than others, > this works on about 3 out of 4 devices. > > For the other devices, I currently use a fairly manual process that > times a lot of write requests and can take a long time. > > > If storage vendors break such fields, it doesn't work well on linux > > which is very popular on mobile world today and user will not use such > > vendor devices and company will be gone. Let's give such pressure to > > them and make vendor keep in promise. > > This could work for eMMC, yes. >
I like it ;) > The SD card standard makes it impossible to write the correct value for > most devices, it only supports power-of-two values up to 4MB for SDHC, > and larger values (I believe 8, 12, 16, 24, ... 64) for SDXC, but a lot > of SDHC cards nowadays use 1.5, 3, 6 or 8 MB erase blocks. > > Arnd > -- > To unsubscribe from this list: send the line "unsubscribe linux-mmc" in > the body of a message to [email protected] > More majordomo info at http://vger.kernel.org/majordomo-info.html
