The patch titled
Subject: mm-vmstat-annotate-data-race-for-zone-free_areanr_free-fix
has been added to the -mm tree. Its filename is
mm-vmstat-annotate-data-race-for-zone-free_areanr_free-fix.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/mm-vmstat-annotate-data-race-for-zone-free_areanr_free-fix.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/mm-vmstat-annotate-data-race-for-zone-free_areanr_free-fix.patch
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------------------------------------------------------
From: Liu Shixin <liushixin2@xxxxxxxxxx>
Subject: mm-vmstat-annotate-data-race-for-zone-free_areanr_free-fix
add comments
Link: https://lkml.kernel.org/r/20210918084655.2696522-1-liushixin2@xxxxxxxxxx
Signed-off-by: Liu Shixin <liushixin2@xxxxxxxxxx>
Cc: "Paul E . McKenney" <paulmck@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/vmstat.c | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)
--- a/mm/vmstat.c~mm-vmstat-annotate-data-race-for-zone-free_areanr_free-fix
+++ a/mm/vmstat.c
@@ -1070,7 +1070,12 @@ static void fill_contig_page_info(struct
for (order = 0; order < MAX_ORDER; order++) {
unsigned long blocks;
- /* Count number of free blocks */
+ /*
+ * Count number of free blocks.
+ *
+ * Access to nr_free is lockless as nr_free is used only for
+ * diagnostic purposes. Use data_race to avoid KCSAN warning.
+ */
blocks = data_race(zone->free_area[order].nr_free);
info->free_blocks_total += blocks;
@@ -1445,6 +1450,10 @@ static void frag_show_print(struct seq_f
seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
for (order = 0; order < MAX_ORDER; ++order)
+ /*
+ * Access to nr_free is lockless as nr_free is used only for
+ * printing purposes. Use data_race to avoid KCSAN warning.
+ */
seq_printf(m, "%6lu ", data_race(zone->free_area[order].nr_free));
seq_putc(m, '\n');
}
_
Patches currently in -mm which might be from liushixin2@xxxxxxxxxx are
mm-vmstat-annotate-data-race-for-zone-free_areanr_free.patch
mm-vmstat-annotate-data-race-for-zone-free_areanr_free-fix.patch
