+ mm-writeback-throttle-based-on-page-writeback-instead-of-congestion.patch added to -mm tree

* + mm-writeback-throttle-based-on-page-writeback-instead-of-congestion.patch added to -mm tree
@ 2021-10-19 22:30 akpm
  0 siblings, 0 replies; 2+ messages in thread
From: akpm @ 2021-10-19 22:30 UTC (permalink / raw)
  To: adilger.kernel, corbet, david, djwong, hannes, hdanton, mgorman,
	mhocko, mm-commits, neilb, riel, shy828301, tytso, vbabka, willy


The patch titled
     Subject: mm/writeback: throttle based on page writeback instead of congestion
has been added to the -mm tree.  Its filename is
     mm-writeback-throttle-based-on-page-writeback-instead-of-congestion.patch

This patch should soon appear at
    https://ozlabs.org/~akpm/mmots/broken-out/mm-writeback-throttle-based-on-page-writeback-instead-of-congestion.patch
and later at
    https://ozlabs.org/~akpm/mmotm/broken-out/mm-writeback-throttle-based-on-page-writeback-instead-of-congestion.patch

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------------------------------------------------------
From: Mel Gorman <mgorman@techsingularity.net>
Subject: mm/writeback: throttle based on page writeback instead of congestion

do_writepages throttles on congestion if the writepages() fails due to a
lack of memory but congestion_wait() is partially broken as the congestion
state is not updated for all BDIs.

This patch stalls waiting for a number of pages to complete writeback that
located on the local node.  The main weakness is that there is no
correlation between the location of the inode's pages and locality but
that is still better than congestion_wait.

Link: https://lkml.kernel.org/r/20211019090108.25501-5-mgorman@techsingularity.net
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: "Darrick J . Wong" <djwong@kernel.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Hillf Danton <hdanton@sina.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: NeilBrown <neilb@suse.de>
Cc: Rik van Riel <riel@surriel.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/page-writeback.c |   11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

--- a/mm/page-writeback.c~mm-writeback-throttle-based-on-page-writeback-instead-of-congestion
+++ a/mm/page-writeback.c
@@ -2366,8 +2366,15 @@ int do_writepages(struct address_space *
 			ret = generic_writepages(mapping, wbc);
 		if ((ret != -ENOMEM) || (wbc->sync_mode != WB_SYNC_ALL))
 			break;
-		cond_resched();
-		congestion_wait(BLK_RW_ASYNC, HZ/50);
+
+		/*
+		 * Lacking an allocation context or the locality or writeback
+		 * state of any of the inode's pages, throttle based on
+		 * writeback activity on the local node. It's as good a
+		 * guess as any.
+		 */
+		reclaim_throttle(NODE_DATA(numa_node_id()),
+			VMSCAN_THROTTLE_WRITEBACK, HZ/50);
 	}
 	/*
 	 * Usually few pages are written by now from those we've just submitted
_

Patches currently in -mm which might be from mgorman@techsingularity.net are

mm-vmscan-throttle-reclaim-until-some-writeback-completes-if-congested.patch
mm-vmscan-throttle-reclaim-and-compaction-when-too-may-pages-are-isolated.patch
mm-vmscan-throttle-reclaim-when-no-progress-is-being-made.patch
mm-writeback-throttle-based-on-page-writeback-instead-of-congestion.patch
mm-page_alloc-remove-the-throttling-logic-from-the-page-allocator.patch
mm-vmscan-centralise-timeout-values-for-reclaim_throttle.patch
mm-vmscan-increase-the-timeout-if-page-reclaim-is-not-making-progress.patch
mm-vmscan-delay-waking-of-tasks-throttled-on-noprogress.patch


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