We've had some issues with writeback in presence of memory reclaim at Facebook, and this patch set attempts to fix it up. The real functional change is the last patch in the series, the first 5 are prep and cleanup patches. The basic idea is that we have callers that call wakeup_flusher_threads() with nr_pages == 0. This means 'writeback everything'. For memory reclaim situations, we can end up queuing a TON of these kinds of writeback units. This can cause softlockups and further memory issues, since we allocate huge amounts of struct wb_writeback_work to handle this writeback. Handle this situation more gracefully. Changes since v1: - Rename WB_zero_pages to WB_start_all (Amir). - Remove a test_bit() for a condition where we always expect the bit to be set. - Remove 'nr_pages' from the wakeup flusher threads helpers, since everybody now passes in zero. Enables further cleanups in later patches too (Jan). - Fix a case where I forgot to clear WB_start_all if 'work' allocation failed. - Get rid of cond_resched() in the wb_do_writeback() loop. -- Jens Axboe -- 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>
