On 3/29/19 9:36 AM, Yafang Shao wrote:
> direct_compaction is not initialized for kcompactd or manually triggered
> compaction (via /proc or /sys).
It doesn't need to, this style of initialization does guarantee that any
field not explicitly mentioned is initialized to 0/NULL/false... and
this pattern is used all over the kernel.
> That may cause unexpected behavior in __compact_finished(), so we should
> set direct_compaction to false explicitly for these compactions.
It's not necessary.
> Signed-off-by: Yafang Shao <laoar.shao@xxxxxxxxx>
> Cc: Vlastimil Babka <vbabka@xxxxxxx>
> ---
> mm/compaction.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/mm/compaction.c b/mm/compaction.c
> index 98f99f4..ba2b711 100644
> --- a/mm/compaction.c
> +++ b/mm/compaction.c
> @@ -2400,13 +2400,12 @@ static void compact_node(int nid)
> .total_free_scanned = 0,
> .mode = MIGRATE_SYNC,
> .ignore_skip_hint = true,
> + .direct_compaction = false,
> .whole_zone = true,
> .gfp_mask = GFP_KERNEL,
> };
>
> -
> for (zoneid = 0; zoneid < MAX_NR_ZONES; zoneid++) {
> -
> zone = &pgdat->node_zones[zoneid];
> if (!populated_zone(zone))
> continue;
> @@ -2522,8 +2521,10 @@ static void kcompactd_do_work(pg_data_t *pgdat)
> .classzone_idx = pgdat->kcompactd_classzone_idx,
> .mode = MIGRATE_SYNC_LIGHT,
> .ignore_skip_hint = false,
> + .direct_compaction = false,
> .gfp_mask = GFP_KERNEL,
> };
> +
> trace_mm_compaction_kcompactd_wake(pgdat->node_id, cc.order,
> cc.classzone_idx);
> count_compact_event(KCOMPACTD_WAKE);
>
