On Tue, May 09, 2017 at 10:03:24AM -1000, Chris Worley wrote: > I realize DIO needs to be 4KB aligned, Actually many file systems do support sector size aligned direct I/O, which could be 512 byte aligned. But as that's not your point :) > but why do large I/Os get > chopped down into 4KB bio's? They shouldn't. What kernel version is this on? > Doing a blocktrace of the md device, even though the app is writing at > 512KB, the MD driver is receiving 4KB bio's. The direct I/O code is using bio_add_page to build the bios it submits. It might be interesting to see which of the checks in it triggers an early return after the first page. -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
