On 12/20/17 12:10 PM, Jens Axboe wrote: > For some reason, commit 966a967116e6 was added to the tree without > CC'ing relevant maintainers, even though it's touching random subsystems. > One example is struct request, a core structure in the block layer. > After this change, struct request grows from 296 to 320 bytes on my > setup. > > Why are we blindly aligning to 32 bytes? The comment says to avoid > it spanning two cache lines - but if that's the case, look at the > actual use case and see if that's actually a problem. For struct > request, it is not. > > Seems to me, this should have been applied in the specific area > where it was needed. Keep struct call_single_data (instead of some > __ version), and just manually align it where it matters. https://marc.info/?l=linux-block&m=151379793913822&w=2 https://marc.info/?l=linux-block&m=151379849914002&w=2 In the future, please CC the relevant folks before making (and committing) changes like that. -- Jens Axboe
