From: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx> Subject: mm/page_alloc: remove the throttling logic from the page allocator The page allocator stalls based on the number of pages that are waiting for writeback to start but this should now be redundant. shrink_inactive_list() will wake flusher threads if the LRU tail are unqueued dirty pages so the flusher should be active. If it fails to make progress due to pages under writeback not being completed quickly then it should stall on VMSCAN_THROTTLE_WRITEBACK. Link: https://lkml.kernel.org/r/20211022144651.19914-6-mgorman@xxxxxxxxxxxxxxxxxxx Signed-off-by: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx> Acked-by: Vlastimil Babka <vbabka@xxxxxxx> Cc: Andreas Dilger <adilger.kernel@xxxxxxxxx> Cc: "Darrick J . Wong" <djwong@xxxxxxxxxx> Cc: Dave Chinner <david@xxxxxxxxxxxxx> Cc: Johannes Weiner <hannes@xxxxxxxxxxx> Cc: Jonathan Corbet <corbet@xxxxxxx> Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxxx> Cc: NeilBrown <neilb@xxxxxxx> Cc: Rik van Riel <riel@xxxxxxxxxxx> Cc: "Theodore Ts'o" <tytso@xxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/page_alloc.c | 21 +-------------------- 1 file changed, 1 insertion(+), 20 deletions(-) --- a/mm/page_alloc.c~mm-page_alloc-remove-the-throttling-logic-from-the-page-allocator +++ a/mm/page_alloc.c @@ -4791,30 +4791,11 @@ should_reclaim_retry(gfp_t gfp_mask, uns trace_reclaim_retry_zone(z, order, reclaimable, available, min_wmark, *no_progress_loops, wmark); if (wmark) { - /* - * If we didn't make any progress and have a lot of - * dirty + writeback pages then we should wait for - * an IO to complete to slow down the reclaim and - * prevent from pre mature OOM - */ - if (!did_some_progress) { - unsigned long write_pending; - - write_pending = zone_page_state_snapshot(zone, - NR_ZONE_WRITE_PENDING); - - if (2 * write_pending > reclaimable) { - congestion_wait(BLK_RW_ASYNC, HZ/10); - return true; - } - } - ret = true; - goto out; + break; } } -out: /* * Memory allocation/reclaim might be called from a WQ context and the * current implementation of the WQ concurrency control doesn't _
