On 12/13/2012 12:08 AM, Darrick J. Wong wrote: > Several complaints have been received regarding long file write latencies when > memory pages must be held stable during writeback. Since it might not be > acceptable to stall programs for the entire duration of a page write (which > may > take many milliseconds even on good hardware), enable a second strategy > wherein > pages are snapshotted as part of submit_bio; the snapshot can be held stable > while writes continue. > > This provides a band-aid to provide stable page writes on jbd without needing > to backport the fixed locking scheme in jbd2. A mount option is added to ext4 > to allow administrators to enable it there.
I'm a bit confused as to what it has to do with ext3. Wouldn't this be useful as a mount option everywhere, though? If this becomes widely used, would it be better to snapshot on wait_for_stable_page instead of on io submission? FWIW, I'm about to pound pretty hard on this whole patchset on a box that doesn't need stable pages. I'll let you know how it goes. --Andy -- 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/
