On Tue, 2 Feb 2010, Olivier Galibert wrote: > > Wouldn't that trigger on lseeks to end of file to get the size? Well, you'd only ever do that with a raw block device, no (if even that: more "raw block device" tools just use the BLKSIZE64 ioctl etc)? Any sane regular file accessor will do 'fstat()' instead. And do we care about startup speed of ramping up read-ahead from the beginning? In fact, the problem case that caused this was literally 'blkid' on a block device - and the fact that the kernel tried to read-ahead TOO MUCh rather than too little. If somebody is really doing lots of serial reading, the read-ahead code will figure it out very quickly. The case this worries about is just the _first_ read, where the question is one of "do we think it might be seeking around, or does it look like the user is going to just read the whole thing"? IOW, if you start off with a SEEK_END, I think it's reasonable to expect it to _not_ read the whole thing. Linus -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
