The patch titled
Subject: mm/page-writeback.c: write_cache_pages(): deduplicate identical checks
has been added to the -mm tree. Its filename is
mm-page-writebackc-write_cache_pages-deduplicate-identical-checks.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-page-writebackc-write_cache_pages-deduplicate-identical-checks.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-page-writebackc-write_cache_pages-deduplicate-identical-checks.patch
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------------------------------------------------------
From: Mauricio Faria de Oliveira <mfo@xxxxxxxxxxxxx>
Subject: mm/page-writeback.c: write_cache_pages(): deduplicate identical checks
There used to be a 'retry' label in between the two (identical) checks
when first introduced in commit f446daaea9d4 ("mm: implement writeback
livelock avoidance using page tagging"), and later modified/updated in
commit 6e6938b6d313 ("writeback: introduce .tagged_writepages for the
WB_SYNC_NONE sync stage").
The label has been removed in commit 64081362e8ff ("mm/page-writeback.c:
fix range_cyclic writeback vs writepages deadlock"), and the (identical)
checks are now present / performed immediately one after another.
So, remove/deduplicate the latter check, moving tag_pages_for_writeback()
into the former check before the 'tag' variable assignment, so it's clear
that it's not used in this (similarly-named) function call but only later
in pagevec_lookup_range_tag().
Link: http://lkml.kernel.org/r/20200218221716.1648-1-mfo@xxxxxxxxxxxxx
Signed-off-by: Mauricio Faria de Oliveira <mfo@xxxxxxxxxxxxx>
Reviewed-by: Ira Weiny <ira.weiny@xxxxxxxxx>
Reviewed-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Jan Kara <jack@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/page-writeback.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
--- a/mm/page-writeback.c~mm-page-writebackc-write_cache_pages-deduplicate-identical-checks
+++ a/mm/page-writeback.c
@@ -2182,12 +2182,12 @@ int write_cache_pages(struct address_spa
if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
range_whole = 1;
}
- if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)
+ if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages) {
+ tag_pages_for_writeback(mapping, index, end);
tag = PAGECACHE_TAG_TOWRITE;
- else
+ } else {
tag = PAGECACHE_TAG_DIRTY;
- if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)
- tag_pages_for_writeback(mapping, index, end);
+ }
done_index = index;
while (!done && (index <= end)) {
int i;
_
Patches currently in -mm which might be from mfo@xxxxxxxxxxxxx are
mm-page-writebackc-write_cache_pages-deduplicate-identical-checks.patch
