On Mon, 2007-06-04 at 12:26 -0400, Aaron Wiebe wrote: > Actually, lets see if I can summarize this more generically... I > realize I'm suggesting something that probably would be a massive > undertaking, but .. > > Regular files are the only interface that requires an application to > wait. With any other case, the nonblocking interfaces are fairly > complete and easy to work with. If userspace could treat regular > files in the same fashion as sockets, life would be good. > > I admittedly do not understand internal kernel semantics in the > differences between a socket and a regular file. Why couldn't we just > have a different 'socket type' like PF_FILE or something like this? > > Abstracting any IO through the existing interfaces provided to sockets > would be ideal from my perspective. The code required to use a file > through these interfaces would be more complex in userspace, but the > abstraction of the current open() itself could simply be an aggregate > of these interfaces without a nonblocking flag. > > It would, however, fix problems around issues with event-based > applications handling events from both disk and sockets. I can't > trigger disk read/write events in the same event handlers I use for > sockets (ie, poll or epoll). I end up having two separate event > handlers - one for disk (currently using glibc's aio thread kludge), > and one for sockets. > > I'm sure this isn't a new idea. Coming from my own development > backround that had little to do with disk, I was actually surprised > when I first discovered that I couldn't edge-trigger disk IO through > poll(). > > Thoughts, comments?
Unless you're planning on rearchitecting the entire VFS lookup and permissions code, you would basically have to fall back onto having a pool of service threads actually perform the I/O. That can just as easily be done today in userland. AFAICS, syslets should give you the means to implement a more scalable scheme, but we'll have to wait and see if/when those are ready for kernel inclusion. Cheers Trond - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
