xfs: do not immediately reuse busy extent ranges
Every time we reallocate a busy extent, we cause a synchronous log force to occur to ensure the freeing transaction is on disk before we continue and use the newly allocated extent. This is extremely sub-optimal as we have to mark every transaction with blocks that get reused as synchronous. Instead of searching the busy extent list after deciding on the extent to allocate, check each candidate extent during the allocation decisions as to whether they are in the busy list. If they are in the busy list, we trim the busy range out of the extent we have found and determine if that trimmed range is still OK for allocation. In many cases, this check can be incorporated into the allocation extent alignment code which already does trimming of the found extent before determining if it is a valid candidate for allocation. Based on earlier patches from Dave Chinner. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Alex Elder <aelder@sgi.com>
Showing
Please register or sign in to comment