By now there're three compaction paths,
- direct compaction
- kcompactd compcation
- proc triggered compaction
When we do compaction in all these paths, we will use compaction_suitable()
to check whether a zone is suitable to do compaction.
There're some issues around the usage of compaction_suitable().
We don't use the proper zoneid in kcompactd_node_suitable() when try to
wakeup kcompactd. In the kcompactd compaction paths, we call
compaction_suitable() twice and the zoneid isn't proper in the second call.
For proc triggered compaction, the classzone_idx is always zero.
In order to fix these issues, I change the type of classzone_idx in the
struct compact_control from const int to int and assign the proper zoneid
before calling compact_zone().
This patch also fixes some comments in struct compact_control, as these
fields are not only for direct compactor but also for all other compactors.
Fixes: ebff398017c6("mm, compaction: pass classzone_idx and alloc_flags to watermark checking")
Fixes: 698b1b30642f("mm, compaction: introduce kcompactd")
Signed-off-by: Yafang Shao <laoar.shao@xxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Cc: Paul Gortmaker <paul.gortmaker@xxxxxxxxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxx>
Cc: Yafang Shao <shaoyafang@xxxxxxxxxxxxxx>
---
mm/compaction.c | 12 +++++-------
mm/internal.h | 10 +++++-----
2 files changed, 10 insertions(+), 12 deletions(-)
diff --git a/mm/compaction.c b/mm/compaction.c
index ac4ead0..984dea7 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -2425,6 +2425,7 @@ static void compact_node(int nid)
continue;
cc.zone = zone;
+ cc.classzone_idx = zoneid;
compact_zone(&cc, NULL);
@@ -2508,7 +2509,7 @@ static bool kcompactd_node_suitable(pg_data_t *pgdat)
continue;
if (compaction_suitable(zone, pgdat->kcompactd_max_order, 0,
- classzone_idx) == COMPACT_CONTINUE)
+ zoneid) == COMPACT_CONTINUE)
return true;
}
@@ -2526,7 +2527,6 @@ static void kcompactd_do_work(pg_data_t *pgdat)
struct compact_control cc = {
.order = pgdat->kcompactd_max_order,
.search_order = pgdat->kcompactd_max_order,
- .classzone_idx = pgdat->kcompactd_classzone_idx,
.mode = MIGRATE_SYNC_LIGHT,
.ignore_skip_hint = false,
.gfp_mask = GFP_KERNEL,
@@ -2535,7 +2535,7 @@ static void kcompactd_do_work(pg_data_t *pgdat)
cc.classzone_idx);
count_compact_event(KCOMPACTD_WAKE);
- for (zoneid = 0; zoneid <= cc.classzone_idx; zoneid++) {
+ for (zoneid = 0; zoneid <= pgdat->kcompactd_classzone_idx; zoneid++) {
int status;
zone = &pgdat->node_zones[zoneid];
@@ -2545,14 +2545,12 @@ static void kcompactd_do_work(pg_data_t *pgdat)
if (compaction_deferred(zone, cc.order))
continue;
- if (compaction_suitable(zone, cc.order, 0, zoneid) !=
- COMPACT_CONTINUE)
- continue;
-
if (kthread_should_stop())
return;
cc.zone = zone;
+ cc.classzone_idx = zoneid;
+
status = compact_zone(&cc, NULL);
if (status == COMPACT_SUCCESS) {
diff --git a/mm/internal.h b/mm/internal.h
index 0d5f720..c224a16 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -190,11 +190,11 @@ struct compact_control {
unsigned long total_free_scanned;
unsigned short fast_search_fail;/* failures to use free list searches */
short search_order; /* order to start a fast search at */
- const gfp_t gfp_mask; /* gfp mask of a direct compactor */
- int order; /* order a direct compactor needs */
- int migratetype; /* migratetype of direct compactor */
- const unsigned int alloc_flags; /* alloc flags of a direct compactor */
- const int classzone_idx; /* zone index of a direct compactor */
+ const gfp_t gfp_mask; /* gfp mask of a compactor */
+ int order; /* order a compactor needs */
+ int migratetype; /* migratetype of a compactor */
+ const unsigned int alloc_flags; /* alloc flags of a compactor */
+ int classzone_idx; /* zone index of a compactor */
enum migrate_mode mode; /* Async or sync migration mode */
bool ignore_skip_hint; /* Scan blocks even if marked skip */
bool no_set_skip_hint; /* Don't mark blocks for skipping */
--
1.8.3.1
