Btrfs: tag pages for writeback in sync (f7aaa06b) · Commits · 戴 / test

Everybody else does this, we need to do it too. If we're syncing, we need to tag the pages we're going to write for writeback so we don't end up writing the same stuff over and over again if somebody is constantly redirtying our file. This will keep us from having latencies with heavy sync workloads. Thanks, Signed-off-by:

Josef Bacik <josef@redhat.com> Signed-off-by:

Chris Mason <chris.mason@oracle.com>

fs/btrfs/extent_io.c

+9 −3

Original line number	Diff line number	Diff line
		@@ -2421,6 +2421,7 @@ static int extent_write_cache_pages(struct extent_io_tree *tree,
		pgoff_t index;
		pgoff_t end; /* Inclusive */
		int scanned = 0;
		int tag;

		pagevec_init(&pvec, 0);
		if (wbc->range_cyclic) {
		@@ -2431,11 +2432,16 @@ static int extent_write_cache_pages(struct extent_io_tree *tree,
		end = wbc->range_end >> PAGE_CACHE_SHIFT;
		scanned = 1;
		}
		if (wbc->sync_mode == WB_SYNC_ALL)
		tag = PAGECACHE_TAG_TOWRITE;
		else
		tag = PAGECACHE_TAG_DIRTY;
		retry:
		if (wbc->sync_mode == WB_SYNC_ALL)
		tag_pages_for_writeback(mapping, index, end);
		while (!done && !nr_to_write_done && (index <= end) &&
		(nr_pages = pagevec_lookup_tag(&pvec, mapping, &index,
		PAGECACHE_TAG_DIRTY, min(end - index,
		(pgoff_t)PAGEVEC_SIZE-1) + 1))) {
		(nr_pages = pagevec_lookup_tag(&pvec, mapping, &index, tag,
		min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1))) {
		unsigned i;

		scanned = 1;

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