On Thu, May 5, 2016 at 9:27 AM, Jeff Moyer <jmoyer@xxxxxxxxxx> wrote: > Michael Callahan <michaelcallahan@xxxxxx> writes: > >> Separate out discards from writes counts in /block/diskstats as well as >> the disk related /sys stat files. >> >> Sign-off-by: Michael Callahan <michaelcallahan@xxxxxx> >> --- >> The STAT_* macros might be better defined somewhere else. >> >> The part_*_in_flight macros should probably be per_cpu. I mixed up a >> patch to test that but they are used awkwardly in drivers/md/dm.c and >> accumulating inflights on cpus would be susceptible to overflow errors >> on 32 bit machines (increment on one cpu, complete on another, they sum >> correctly until one overflows) >> >> This patch adds the new stats to the end of stat and diskstat for more >> backwards compatibility. However this patch breaks iostat which will >> need to be updated to grab the additional fields. iostat already has >> cases for 4 and 11 entries in stat so adding another for 15 should be >> easy enough and it's likely that adding these to the end of the file >> rather than right after the write stats is unnecessary. > > You can't just break iostat. Split the fields out into another file. > > Cheers, > Jeff Would it be better to make a new stat2 file, make discard_stats, or to patch iostat.c to handle the new format? It appears that iostat.c already checks for 4 or 11 stat fields and should be easy to extend to check for 15. Michael -- To unsubscribe from this list: send the line "unsubscribe linux-block" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
