Re: [PATCH 25/26] block: Reduce zone write plugging memory usage

Bart Van Assche
2024-02-09T19:36:46Z

On 2/8/24 19:58, Damien Le Moal wrote:
> We still need to keep in memory the write pointer offset of zones that are not
> being actively written to but have been previously partially written. So I do
> not see how excluding empty and full zones from that tracking simplifies
> anything at all. And the union of wp offset+zone capacity with a pointer to the
> active zone plug structure is not *that* complicated to handle...

Multiple zoned storage device have 1000 or more zones. The number of partially
written zones is typically less than 10. Hence, tracking the partially written
zones only will result in significantly less memory being used, fewer CPU cache
misses and fewer MMU TLB lookup misses. I expect that this will matter since the
zone information data structure will be accessed every time a zoned write bio is
processed.

Bart.