On Fri, Dec 14, 2018 at 8:08 PM Coly Li <[email protected]> wrote: > Commit b1092c9af9ed ("bcache: allow quick writeback when backing idle") > just looks at single bcache device. If there are I/Os for other bcache > device on the cache set, and a single bcache device is idle, a faster > writeback rate for this single idle bcache device will happen, I/O to > read dirty data on cache for writeback will have negative impact to I/O > requests of other bcache devices.
Yes, but this will potentially fill the queue on the idle device. If you have an application that is intermittently doing I/O every few seconds, the latency of the individual I/Os will be high. I was told during review that this was unacceptable, and revised my patch. But now we have merged a change that is more like my first patch that was rejected... Mike
