Why set ppa.g.blk = zns->active_zone in get_new_page?

[realcedriccheng]

Hi，

I found that when getting a new ppa, FEMU sets ppa.g.blk as zns->active_zone.

FEMU/hw/femu/zns/zftl.c

Line 147 in cf05b1c

ppa.g.blk = zns->active_zone;

Where zns->active_zone is the current zone id and ppa.g.blk cannot be greater than NUM_BLOCKS_PER_CHIP.

So this means that the number of zones cannot be greater than NUM_BLOCKS_PER_CHIP, and when the zone size is small, the ppa would be invalid.

For example, I currently set SSD_SIZE_MB=32768 and ZONE_SIZE=128 while NUM_BLOCKS_PER_CHIP=32. So I have 256 zones but I can only use 32 of them, otherwise the ppa would be invalid.

This behavior seems a bit unexpected. Could you please provide some guidance or clarification on this issue?

[DingcuiYu]

Great question, thanks for pointing it out! I've defaulted to a zone size equal to a superblock in the current version. You can modify it to suit your needs.