On Tue, 2005-03-01 at 14:01, Jeff Garzik wrote: > Ming Zhang wrote: > > On Tue, 2005-03-01 at 13:37, Arjan van de Ven wrote: > > > >>On Tue, 2005-03-01 at 10:24 -0800, Bryan Henderson wrote: > >> > >>>One thing that's implicit in your reasons for wanting to be in the kernel > >>>is that you've chosen to exploit the kernel's page cache. As a user of > >>>the page cache, you have more control from inside the kernel than from > >>>user space. The page cache was designed to be fundamentally invisible to > >>>user space. > >>> > >>>A pure user space implementation of an ISCSI target would use process > >>>virtual memory for a cache and manage it itself. It would access the > >>>storage with direct I/O. > >> > >>why would it use direct I/O ? Direct I/O would be really stupid for such > >>a thing to use since that means there's no caching going on *at all*. > >> > > > > what Bryan suggest is a privately owned and managed user space cache. so > > for that disk write should be real write-through. > > > > it is hard to beat linux kernel cache performance though. > > A privately managed user space cache uses Linux kernel cache. what i mean is private cache algorithms. for example, windows request are not page size aligned so some bitmap based cache algorithms might be useful.
> > As does mmap/sendfile... > > Jeff > - To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
