2014-05-01 9:45 GMT+09:00 David Rientjes <rient...@google.com>: > Synchronous memory compaction can be very expensive: it can iterate an > enormous > amount of memory without aborting and it can wait on page locks and writeback > to > complete if a pageblock cannot be defragmented. > Unfortunately, it's too expensive for pagefault for transparent hugepages and > it's much better to simply fallback to pages. On 128GB machines, we find that > synchronous memory compaction can take O(seconds) for a single thp fault.
Hello, AFAIK, synchronous compaction doesn't wait the page on writeback. sync compaction pass MIGRATE_SYNC_LIGHT for migrate_mode, instead of MIGRATE_SYNC. It results in skipping the page on writeback. Thanks. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
