[PATCH 6/5] mm: compaction: have compaction_suitable() return bool

From: Johannes Weiner
Date: Fri Jun 02 2023 - 11:12:45 EST


Since it only returns COMPACT_CONTINUE or COMPACT_SKIPPED now, a bool
return value simplifies the callsites.

Suggested-by: Vlastimil Babka <vbabka@xxxxxxx>
Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx>
---
include/linux/compaction.h | 6 ++--
mm/compaction.c | 64 ++++++++++++++++++--------------------
mm/vmscan.c | 6 ++--
3 files changed, 36 insertions(+), 40 deletions(-)

diff --git a/include/linux/compaction.h b/include/linux/compaction.h
index 9f7cf3e1bf89..57b16e69c19a 100644
--- a/include/linux/compaction.h
+++ b/include/linux/compaction.h
@@ -89,7 +89,7 @@ extern enum compact_result try_to_compact_pages(gfp_t gfp_mask,
const struct alloc_context *ac, enum compact_priority prio,
struct page **page);
extern void reset_isolation_suitable(pg_data_t *pgdat);
-extern enum compact_result compaction_suitable(struct zone *zone, int order,
+extern bool compaction_suitable(struct zone *zone, int order,
int highest_zoneidx);

extern void compaction_defer_reset(struct zone *zone, int order,
@@ -107,10 +107,10 @@ static inline void reset_isolation_suitable(pg_data_t *pgdat)
{
}

-static inline enum compact_result compaction_suitable(struct zone *zone, int order,
+static inline bool compaction_suitable(struct zone *zone, int order,
int highest_zoneidx)
{
- return COMPACT_SKIPPED;
+ return false;
}

static inline void kcompactd_run(int nid)
diff --git a/mm/compaction.c b/mm/compaction.c
index fdee5f1ac5a1..d354d8af157c 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -2205,9 +2205,9 @@ static enum compact_result compact_finished(struct compact_control *cc)
return ret;
}

-static enum compact_result __compaction_suitable(struct zone *zone, int order,
- int highest_zoneidx,
- unsigned long wmark_target)
+static bool __compaction_suitable(struct zone *zone, int order,
+ int highest_zoneidx,
+ unsigned long wmark_target)
{
unsigned long watermark;
/*
@@ -2227,27 +2227,20 @@ static enum compact_result __compaction_suitable(struct zone *zone, int order,
watermark = (order > PAGE_ALLOC_COSTLY_ORDER) ?
low_wmark_pages(zone) : min_wmark_pages(zone);
watermark += compact_gap(order);
- if (!__zone_watermark_ok(zone, 0, watermark, highest_zoneidx,
- ALLOC_CMA, wmark_target))
- return COMPACT_SKIPPED;
-
- return COMPACT_CONTINUE;
+ return __zone_watermark_ok(zone, 0, watermark, highest_zoneidx,
+ ALLOC_CMA, wmark_target);
}

/*
* compaction_suitable: Is this suitable to run compaction on this zone now?
- * Returns
- * COMPACT_SKIPPED - If there are too few free pages for compaction
- * COMPACT_CONTINUE - If compaction should run now
*/
-enum compact_result compaction_suitable(struct zone *zone, int order,
- int highest_zoneidx)
+bool compaction_suitable(struct zone *zone, int order, int highest_zoneidx)
{
- enum compact_result ret;
- int fragindex;
+ enum compact_result compact_result;
+ bool suitable;

- ret = __compaction_suitable(zone, order, highest_zoneidx,
- zone_page_state(zone, NR_FREE_PAGES));
+ suitable = __compaction_suitable(zone, order, highest_zoneidx,
+ zone_page_state(zone, NR_FREE_PAGES));
/*
* fragmentation index determines if allocation failures are due to
* low memory or external fragmentation
@@ -2264,17 +2257,24 @@ enum compact_result compaction_suitable(struct zone *zone, int order,
* excessive compaction for costly orders, but it should not be at the
* expense of system stability.
*/
- if (ret == COMPACT_CONTINUE && (order > PAGE_ALLOC_COSTLY_ORDER)) {
- fragindex = fragmentation_index(zone, order);
- if (fragindex >= 0 && fragindex <= sysctl_extfrag_threshold)
- ret = COMPACT_NOT_SUITABLE_ZONE;
+ if (suitable) {
+ compact_result = COMPACT_CONTINUE;
+ if (order > PAGE_ALLOC_COSTLY_ORDER) {
+ int fragindex = fragmentation_index(zone, order);
+
+ if (fragindex >= 0 &&
+ fragindex <= sysctl_extfrag_threshold) {
+ suitable = false;
+ compact_result = COMPACT_NOT_SUITABLE_ZONE;
+ }
+ }
+ } else {
+ compact_result = COMPACT_SKIPPED;
}

- trace_mm_compaction_suitable(zone, order, ret);
- if (ret == COMPACT_NOT_SUITABLE_ZONE)
- ret = COMPACT_SKIPPED;
+ trace_mm_compaction_suitable(zone, order, compact_result);

- return ret;
+ return suitable;
}

bool compaction_zonelist_suitable(struct alloc_context *ac, int order,
@@ -2300,7 +2300,7 @@ bool compaction_zonelist_suitable(struct alloc_context *ac, int order,
available = zone_reclaimable_pages(zone) / order;
available += zone_page_state_snapshot(zone, NR_FREE_PAGES);
if (__compaction_suitable(zone, order, ac->highest_zoneidx,
- available) == COMPACT_CONTINUE)
+ available))
return true;
}

@@ -2341,11 +2341,10 @@ compact_zone(struct compact_control *cc, struct capture_control *capc)
cc->highest_zoneidx, cc->alloc_flags))
return COMPACT_SUCCESS;

- ret = compaction_suitable(cc->zone, cc->order,
- cc->highest_zoneidx);
/* Compaction is likely to fail */
- if (ret == COMPACT_SKIPPED)
- return ret;
+ if (!compaction_suitable(cc->zone, cc->order,
+ cc->highest_zoneidx))
+ return COMPACT_SKIPPED;
}

/*
@@ -2846,7 +2845,7 @@ static bool kcompactd_node_suitable(pg_data_t *pgdat)
continue;

if (compaction_suitable(zone, pgdat->kcompactd_max_order,
- highest_zoneidx) == COMPACT_CONTINUE)
+ highest_zoneidx))
return true;
}

@@ -2888,8 +2887,7 @@ static void kcompactd_do_work(pg_data_t *pgdat)
min_wmark_pages(zone), zoneid, 0))
continue;

- if (compaction_suitable(zone, cc.order,
- zoneid) != COMPACT_CONTINUE)
+ if (!compaction_suitable(zone, cc.order, zoneid))
continue;

if (kthread_should_stop())
diff --git a/mm/vmscan.c b/mm/vmscan.c
index c0cfa9b86b48..e9a8ca124982 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -6402,8 +6402,7 @@ static inline bool should_continue_reclaim(struct pglist_data *pgdat,
sc->reclaim_idx, 0))
return false;

- if (compaction_suitable(zone, sc->order,
- sc->reclaim_idx) == COMPACT_CONTINUE)
+ if (compaction_suitable(zone, sc->order, sc->reclaim_idx))
return false;
}

@@ -6599,8 +6598,7 @@ static inline bool compaction_ready(struct zone *zone, struct scan_control *sc)
return true;

/* Compaction cannot yet proceed. Do reclaim. */
- if (compaction_suitable(zone, sc->order,
- sc->reclaim_idx) == COMPACT_SKIPPED)
+ if (!compaction_suitable(zone, sc->order, sc->reclaim_idx))
return false;

/*
--
2.40.1