On 01/10/2017 04:38 AM, Hugh Dickins wrote: > On Mon, 9 Jan 2017, David Rientjes wrote: >> On Mon, 9 Jan 2017, Vlastimil Babka wrote: >> >>>> Any suggestions for a better name for "background" are more than welcome. >>> >>> Why not just "madvise+defer"? >>> >> >> Seeing no other activity regarding this issue (omg!), I'll wait a day or >> so to see if there are any objections to "madvise+defer" or suggestions >> that may be better and repost. > > I get very confused by the /sys/kernel/mm/transparent_hugepage/defrag > versus enabled flags, and this may be a terrible, even more confusing, > idea: but I've been surprised and sad to see defrag with a "defer" > option, but poor enabled without one; and it has crossed my mind that > perhaps the peculiar "madvise+defer" syntax in defrag might rather be > handled by "madvise" in defrag with "defer" in enabled? Or something > like that: 4 x 4 possibilities instead of 5 x 3. But would all the possibilities make sense? For example, if I saw "defer" in enabled, my first expectation would be that it would only use khugepaged, and no THP page faults at all - possibly including madvised regions. If we really wanted really to cover the whole configuration space, we would have files called "enable", "defrag", "enable-madvise", "defrag-madvise" and each with possible values "yes", "no", "defer", where "defer" for enable* files would mean to skip THP page fault completely and defer to khugepaged, and "defer" for defrag* files would mean wake up kswapd/kcompactd and skip direct reclaim/compaction. But, too late for that :) > > Please be gentle with me, > Hugh > -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>