On Tue, Sep 02, 2025 at 08:36:51AM -0600, Keith Busch wrote: > > We are actually about to run out of REQ_* bits with the current > > encoding. We could shrink the space for REQ_OP_ a bit to create > > more, or try to move some flags out into BIO_ flags (like > > REQ_ALLOC_CACHE) or kill them by looking at pointers instead > > (REQ_INTEGRITY), or by overlaying flags that can't be used with > > the same of (REQ_FUA vs REQ_RAHEAD vs REQ_UNMAP for example). > > And maybe we can come up with a more coherent scheme for > > REQ_PRIO / REQ_BACKGROUND / REQ_SWAP and maybe REQ_IDLE that create > > another priority scheme in addition to the I/O priorities. > > Sure, but can we do that effort separately from this? I'm mainly trying > to align with Leon's DMA series that adds REQ_MMIO so that we won't have > flag conflicts. I was just thinking out aloud how we could reclaim them, not trying to take that on for this series.
