Commit 9b0d3ace authored Feb 04, 2009 by Chris Mason

Btrfs: don't return congestion in write_cache_pages as often



On fast devices that go from congested to uncongested very quickly, pdflush
is waiting too often in congestion_wait, and the FS is backing off to
easily in write_cache_pages.

For now, fix this on the btrfs side by only checking congestion after
some bios have already gone down.  Longer term a real fix is needed
for pdflush, but that is a larger project.

Signed-off-by: Chris Mason <chris.mason@oracle.com>

parent 7b78c170

fs/btrfs/extent_io.c

+0 −5

Original line number	Diff line number	Diff line
		@@ -2377,11 +2377,6 @@ static int extent_write_cache_pages(struct extent_io_tree *tree,
		int scanned = 0;
		int range_whole = 0;

		if (wbc->nonblocking && bdi_write_congested(bdi)) {
		wbc->encountered_congestion = 1;
		return 0;
		}

		pagevec_init(&pvec, 0);
		if (wbc->range_cyclic) {
		index = mapping->writeback_index; /* Start from prev offset */