On Mon, Oct 22, 2012 at 10:15:00AM -0500, Dave Kleikamp wrote: > This is the current version of the patchset I presented at the LSF-MM > Summit in San Francisco in April. I apologize for letting it go so > long before re-submitting. > > This patchset was begun by Zach Brown and was originally submitted for > review in October, 2009. Feedback was positive, and I have picked up > where he left off, porting his patches to the latest mainline kernel > and adding support more file systems. > > This patch series adds a kernel interface to fs/aio.c so that kernel code can > issue concurrent asynchronous IO to file systems. It adds an aio command and > file system methods which specify io memory with pages instead of userspace > addresses. > > This series was written to reduce the current overhead loop imposes by > performing synchronus buffered file system IO from a kernel thread. These > patches turn loop into a light weight layer that translates bios into iocbs. > > The downside of this is that in its current implementation, performance takes > a big hit for non-synchonous I/O, since the underlying page cache is bypassed. > The tradeoff is that all writes to the loop device make it to the underlying > media, making loop-mounted file systems recoverable. It also seems to still not fully kill thr old aio_read/write codepath. At least XFS isn't touched yet. It also doesn't seem to kill the nasty hack for in-kernel direct I/O introduced with the swap over nfs code (grep for REQ_KERNEL / KERNEL_READ / KERNEL_WRITE) -- 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
