On Wed, Aug 21, 2019 at 10:26:43AM +1000, Dave Chinner wrote: > After thinking on this for a bit, I suspect the better thing to do > here is add a KM_ALIGNED flag to the allocation, so if the internal > kmem_alloc() returns an unaligned pointer we free it and fall > through to vmalloc() to get a properly aligned pointer.... > > That way none of the other interfaces have to change, and we can > then use kmem_alloc_large() everywhere we allocate buffers for IO. > And we don't need new infrastructure just to support these debug > configurations, either. > > Actually, kmem_alloc_io() might be a better idea - keep the aligned > flag internal to the kmem code. Seems like a pretty simple solution > to the entire problem we have here... The interface sounds ok. The simple try and fallback implementation OTOH means we always do two allocations іf slub debugging is enabled, which is a little lasty. I guess the best we can do for 5.3 and then figure out a way to avoid for later.
