Hi,
On 2020/03/30 22:53, Keith Busch wrote:
On Mon, Mar 30, 2020 at 06:15:41PM +0900, Tokunori Ikegami wrote:
But there is a case that the command data length is limited by 512KB.
I am not sure about this condition so needed more investigation.
Your memory is too fragmented. You need more physically contiguous
memory or you'll hit the segment limit before you hit the length
limit. Try allocating huge pages.
Thank you so much for your advise.
I have confirmed that the 512KB case is limited by the 127 segments
check below in ll_new_hw_segment().
if (req->nr_phys_segments + nr_phys_segs >
queue_max_segments(req->q)) {
Also confirmed that the 4MB limit works correctly with the memory
condition not fragmented too much.
I will do abandon the patch to increase max segments as limited 4MB now
by NVMe PCIe driver.
Regards,
Ikegami
