On 06/30/2010 11:42 AM, Christoph Hellwig wrote: > On Wed, Jun 30, 2010 at 11:32:43AM +0300, Boaz Harrosh wrote: >> May I ask a silly question? Why the dynamic allocation? >> >> Why not have a const-static single global page at the block-layer somewhere >> that will be used for all discard-type operations and be done with it once and >> for all. A single page can be used for any size bio , any number of concurrent >> discards, any ZERO needed operation. It can also be used by other operations >> like padding and others. In fact isn't there one for the libsata padding? > > for UNMAP we need to write into the payload. And for ATA TRIM we need > to write into the WRITE SAME payload. OK, Thanks, I see. Is it one of these operations, (like we have in OSD) where the CDB information spills into the payload? like the scatter-gather and extent lists and such. Do we actually use a WRITE_SAME which is not zero? for what use? > That's another layering violation > for those looking for them, btw.. > Agreed -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel