On 18/06/2020 21.21, Kanchan Joshi wrote:

On Thu, Jun 18, 2020 at 10:04:32AM +0200, Matias Bjørling wrote:

quoted

On 17/06/2020 19.23, Kanchan Joshi wrote:

quoted

This patchset enables issuing zone-append using aio and io-uring 
direct-io interface.

For aio, this introduces opcode IOCB_CMD_ZONE_APPEND. Application 
uses start LBA
of the zone to issue append. On completion 'res2' field is used to 
return
zone-relative offset.

For io-uring, this introduces three opcodes: 
IORING_OP_ZONE_APPEND/APPENDV/APPENDV_FIXED.
Since io_uring does not have aio-like res2, cqe->flags are 
repurposed to return zone-relative offset

Please provide a pointers to applications that are updated and ready 
to take advantage of zone append.

I do not believe it's beneficial at this point to change the libaio 
API, applications that would want to use this API, should anyway 
switch to use io_uring.

Please also note that applications and libraries that want to take 
advantage of zone append, can already use the zonefs file-system, as 
it will use the zone append command when applicable.

AFAIK, zonefs uses append while serving synchronous I/O. And append bio
is waited upon synchronously. That maybe serving some purpose I do
not know currently. But it seems applications using zonefs file
abstraction will get benefitted if they could use the append 
themselves to
carry the I/O, asynchronously.

Yep, please see Christoph's comment regarding adding the support to zonefs.