(2014/05/21 12:19), Chen Yucong wrote: > On Wed, 2014-05-21 at 11:43 +0900, Hidetoshi Seto wrote: >> (2014/05/21 11:03), Chen Yucong wrote: >>> On Wed, 2014-05-21 at 10:40 +0900, Hidetoshi Seto wrote: >>>> (2014/05/20 11:11), Chen Yucong wrote: >>>>> mces_seen is a Per-CPU variable which should only be accessed by Per-CPU >>>>> as possible. So the >>>>> clear operation of mces_seen should also be lcoal to Per-CPU rather than >>>>> monarch CPU. >>>> >>>> I don't think it should be local. >>>> Originally what we want to have here is memory to save mces_seen for each >>>> online cpus, >>>> such as a global array like mces_seen[cpus]. But at same time we don't >>>> want to preallocate >>>> big array enough for max possible cpus. So we use per-cpu store instead. >>>> >>> But mces_seen will just be updated by Per-CPU rather than monarch CPU. >>> It is only read by monarch CPU. >> >> Because mce status registers are per-cpu and monarch cannot access subjects' >> registers >> directly, > Right. This is one reason why we need to distribute the clear operation > to Per-CPU. And in fact it exactly assigns per-cpu property to > mces_seen. > >> all subjects read it's status for monarch, store the status to memory for >> monarch, >> and then monarch gather all status to make decision for all. > > mce_regin, which is only called by monarch CPU, can be used for system > panics as quickly as possible if there is a truly data corrupting error. > But Monarch CPU don't have to help all other CPU to clean mces_clean. > One advantage of Per-CPU is the isolation of errors propagation, being > so, why do not we clean mces_seen by Per-CPU?
What kind of error propagations are you expecting/concerning here? Could you explain the problem more in detail? Thanks, H.Seto -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
