Rereading this... On 12/19/2016 12:53 AM, Hans van Kranenburg wrote: > [...] > > Qu Wenruo pointed out that the greyscale value used for dev_extent (the > usage for the block group is used here) does not necessarily have to be > correct: "And for 50%/50% assumption for RAID0, it's not true and we can > easily create a case where it's 100%/0%". (Qu) > > I replied on that with "OTOH, for most cases it will still be correct > enough for the eye, because statistically seen, distribution of data > over the stripes will be more uniform more often than not". > > Still, "The point is, for full fs or per-device output, a developer may > focus on the fragments of unallocated space in each device." (Qu) What does "unallocated" mean here? I always use "unallocated" for space that is not part of a dev_extent/chunk/blockgroup at all, and "unused" for free space inside allocated space. > The last commit, "Don't hardcode minimal brightness for dev_extents" > exposes the min_brightness, which tunes the brightness range of > allocated space. "Setting it to 255 will cause any allocated space to > show up as bright white, regardless of usage." If meant as unused free space in allocated dev_extent space, then this does not help much of course. OTOH, I don't think the information of data distribution over dev_extents belonging to a single blockgroup is available at all, when walking the IOCTL paths. -- Hans van Kranenburg -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
