From ea6813be07dcdc072aa9ad18099115a74cecb5e1 Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Thu, 23 Jun 2022 10:51:44 -0700 Subject: mm: Move starting of background writeback into the main balancing loop We start background writeback if we are over background threshold after exiting the main loop in balance_dirty_pages(). This may result in basing the decision on already stale values (we may have slept for significant amount of time) and it is also inconvenient for refactoring needed for async dirty throttling. Move the check into the main waiting loop. Signed-off-by: Jan Kara Signed-off-by: Stefan Roesch Link: https://lore.kernel.org/r/20220623175157.1715274-2-shr@fb.com Signed-off-by: Jens Axboe --- mm/page-writeback.c | 31 ++++++++++++++----------------- 1 file changed, 14 insertions(+), 17 deletions(-) diff --git a/mm/page-writeback.c b/mm/page-writeback.c index 55c2776ae699..e59c523aed1a 100644 --- a/mm/page-writeback.c +++ b/mm/page-writeback.c @@ -1627,6 +1627,19 @@ static void balance_dirty_pages(struct bdi_writeback *wb, } } + /* + * In laptop mode, we wait until hitting the higher threshold + * before starting background writeout, and then write out all + * the way down to the lower threshold. So slow writers cause + * minimal disk activity. + * + * In normal mode, we start background writeout at the lower + * background_thresh, to keep the amount of dirty memory low. + */ + if (!laptop_mode && nr_reclaimable > gdtc->bg_thresh && + !writeback_in_progress(wb)) + wb_start_background_writeback(wb); + /* * Throttle it only when the background writeback cannot * catch-up. This avoids (excessively) small writeouts @@ -1657,6 +1670,7 @@ free_running: break; } + /* Start writeback even when in laptop mode */ if (unlikely(!writeback_in_progress(wb))) wb_start_background_writeback(wb); @@ -1823,23 +1837,6 @@ pause: if (!dirty_exceeded && wb->dirty_exceeded) wb->dirty_exceeded = 0; - - if (writeback_in_progress(wb)) - return; - - /* - * In laptop mode, we wait until hitting the higher threshold before - * starting background writeout, and then write out all the way down - * to the lower threshold. So slow writers cause minimal disk activity. - * - * In normal mode, we start background writeout at the lower - * background_thresh, to keep the amount of dirty memory low. - */ - if (laptop_mode) - return; - - if (nr_reclaimable > gdtc->bg_thresh) - wb_start_background_writeback(wb); } static DEFINE_PER_CPU(int, bdp_ratelimits); -- cgit v1.2.3-59-g8ed1b