Hi maintainers and folks, Some patches of this patch set have been sent before, they are not merged yet, and I add two new patches to solve some issues I found while testing. since They are interdependent, so I make a patch set and resend them. [PATCH 1/4] bcache: finish incremental GC [PATCH 2/4] bcache: calculate the number of incremental GC nodes according to the total of btree nodes [PATCH 3/4] bcache: notify allocator to prepare for GC [PATCH 4/4] bcache: fix I/O significant decline while backend devices registering These patches are useful to prevent I/O fluctuations or even jump 0 while GC or cached devices registering. I have test them for some times, I hope somebody could have a review for these patch, any comment would be welcome. Patch v2: modify patch as Coly's suggestion.
