On Sat, Feb 21, 2015 at 09:53:45AM -0800, Sage Weil wrote: > Ah, thanks. I guess in the buffered case though we won't block normally > anyway (unless we've hit the bdi dirty threshold). So it's probably > either aio direct or buffered write + aio fsync, depending on the cache > hints?
buffered I/O will also block on: - acquiring i_mutex (do you plan on having parallel writers to the same file?) - reading in the page for read-modify-write cycles - waiting for writeback to finish for a previous write to the page In adition to all the other ways even O_DIRECT aio could block (most importantly block allocation) I have a hacked prototype to do non-blocking writes similar to the non-blocking reads we've been discussion on fsdevel for the last half year. -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
