How does the output of zramctl relate to swapped memory usage?

I have a Raspberry PI 5 with 8GB of ram. I have allocated a zram swap partition with disksize of 1GB, which after a few days is now being used. $ free -hw total used free shared buffers cache available Mem: 7.8Gi 4.1Gi 390Mi 258Mi 855Mi 3.1Gi 3.6Gi Swap: 1.0Gi 694Mi 329Mi $ zramctl NAME ALGORITHM DISKSIZE DATA COMPR TOTAL STREAMS MOUNTPOINT /dev/zram0 lzo-rle 1G 445.6M 78.4M 82.6M 4 [SWAP] $ zramctl --output-all NAME DISKSIZE DATA COMPR ALGORITHM STREAMS ZERO-PAGES TOTAL MEM-LIMIT MEM-USED MIGRATED MOUNTPOINT /dev/zram0 1G 445.6M 78.4M lzo-rle 4 263 82.6M 0B 116.5M 5.3K [SWAP] The "free" program states that I am using about 70% of my zram swap (~700MB). The graphical memory display of "top" agrees with this. Looking at zramctl, it agrees on disksize, but the only way I can make any sense of this is to assume that my swap contains 445.6MB of swapped data (compressed from ~700MB). If this _is_ the case, what is the meaning of the other columns in zramctl output (most importantly, COMPR, TOTAL, & MEM-USED). If not, please point out my misunderstanding. I have read the kernel documentation, but that is mostly regarding the zram "core", rather than actual operation of swap.