Hi Sagi, > Does the attached patch work for you? This patch _does_ work for our tests. I see all the writes aligned to 512 bytes as, I think, would be expected. Thanks! Just for your information, using the bpftrace script earlier in this thread, the output is as follows. The lines with 2 values shows the first two arguments to 'bio_add_page()', the lines with 4 values shows the first 4 arguments to `brd_do_bvec()`. For the successful case on the new patch: # bpftrace isert.bt Attaching 4 probes... 512 3072 512 3072 1 131071 4096 0 4096 0 0 0 4096 0 4096 0 0 8 4096 0 4096 0 0 131064 4096 512 3584 512 1 131064 512 0 1 131071 512 0 512 0 0 131071 And for the failed case on the older unpatched code: # bpftrace ./isert.bt Attaching 4 probes... 512 76 512 76 1 131071 4096 0 4096 0 0 0 4096 0 4096 0 0 8 4096 0 4096 0 0 131064 4096 76 4020 76 1 131064 76 0 1 131071 512 0 512 0 0 131071 Thanks again! Steve