On Wed, 2011-05-04 at 14:55 -0400, Christoph Hellwig wrote: > Blocks for the allocation btree are allocated from and release to > the AGFL, and thus frequently reused. Even worse we do not have > an easy way to avoid using an AGFL block when it is discarded due > to the simple FILO list of free blocks, and thus can frequently > stall on blocks that are currently undergoing a discard. > > Add a flag to the busy extent tracking structure to skip the discard for > allocation btree blocks. In normal operation these blocks are reused > frequently enough that there is no need to discard them anyway, but > if they spill over to the allocation btree as part of a balance we > "leak" blocks that we would otherwise discard. We could fix this > by adding another flag and keeping these block in the rbtree even > after they aren't busy any more so that we could discard them when > they migrate out of the AGFL. Given that this would cause significant > overhead I don't think it's worthwile for now. > > Signed-off-by: Christoph Hellwig <hch@xxxxxx> This one looks good. (If you add support for discard with nodelaylog it will need to be updated.) Reviewed-by: Alex Elder <aelder@xxxxxxx> _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
