On 08/13/2015 12:11 AM, Jeff Moyer wrote: > Boaz Harrosh <boaz@xxxxxxxxxxxxx> writes: > >> On 08/07/2015 11:41 PM, Jeff Moyer wrote: >> <> >>> >>>> We need to cope with the case where the end of a partition isn't on a >>>> page boundary though. >>> >>> Well, that's usually done by falling back to buffered I/O. I gave that >>> a try and panicked the box. :) I'll keep looking into it, but probably >>> won't have another patch until next week. >>> >> >> lets slow down for a sec, please. >> >> We have all established that an unaligned partition start is BAD and not supported? > > No. Unaligned partitions on RAID arrays or 512e devices are bad because > they result in suboptimal performance. They are most certainly still > supported, though. > What ? I meant for dax on pmem or brd. I meant that we *do not* support dax access on an unaligned partition start. (None dax is perfectly supported) We did it this way because of the direct_access API that returns a pfn with is PAGE_SIZE. We could introduce a pfn+offset but we thought it is not worth it, and that dax should be page aligned for code simplicity Cheers Boaz > -Jeff > -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
