Hello, recently I've been looking into 10% regression reported by our performance measurement infrastructure in reaim benchmark that was bisected down to 5a9d041ba2f6 ("block: move io_context creation into where it's needed"). This didn't really make much sense and it took me a while to understand this but the culprit is actually in even older commit e70344c05995 ("block: fix default IO priority handling") and 5a9d041ba2f6 just made the breakage visible. Essentially the problem was that after these commits some IO was queued with IO priority class IOPRIO_CLASS_BE while other IO was queued with IOPRIO_CLASS_NONE and as a result they could not be merged together resulting in performance regression. I think what commit e70344c05995 ("block: fix default IO priority handling") did is actually broken not only because of this performance regression but because of other reasons as well (see changelog of patch 3/3 for details) so this patch set aims at fixing it. Honza