On 4/10/19 8:56 PM, Yang Shi wrote: > When demoting to PMEM node, the target node may have memory pressure, > then the memory pressure may cause migrate_pages() fail. > > If the failure is caused by memory pressure (i.e. returning -ENOMEM), > tag the node with PGDAT_CONTENDED. The tag would be cleared once the > target node is balanced again. > > Check if the target node is PGDAT_CONTENDED or not, if it is just skip > demotion. This seems like an actively bad idea to me. Why do we need an *active* note to say the node is contended? Why isn't just getting a failure back from migrate_pages() enough? Have you observed this in practice?
