On 8/15/2023 8:04 PM, Kemeng Shi wrote:
on 8/15/2023 4:58 PM, Baolin Wang wrote:
On 8/5/2023 7:07 PM, Kemeng Shi wrote:
We have order = -1 via proactive compaction, the is_via_compact_memory is
not proper name anymore.
As cc->order informs the compaction to satisfy a allocation with that
order, so rename it to compaction_with_allocation_order.
Signed-off-by: Kemeng Shi <shikemeng@xxxxxxxxxxxxxxx>
---
mm/compaction.c | 11 +++++------
1 file changed, 5 insertions(+), 6 deletions(-)
diff --git a/mm/compaction.c b/mm/compaction.c
index d8416d3dd445..b5a699ed526b 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -2055,12 +2055,11 @@ static isolate_migrate_t isolate_migratepages(struct compact_control *cc)
}
/*
- * order == -1 is expected when compacting via
- * /proc/sys/vm/compact_memory
+ * compact to satisfy allocation with target order
*/
-static inline bool is_via_compact_memory(int order)
+static inline bool compaction_with_allocation_order(int order)
I know naming is hard, but this name is not good enough that can show the compaction mode. But the original one could.
Yes, I agree with this, but name and comment of is_via_compact_memory may
mislead reader that order == -1 is equivalent to compaction from
/proc/sys/vm/compact_memory.
Actually, we have several approaches to trigger compaction with order == -1:
1. via /proc/sys/vm/compact_memory
2. via /sys/devices/system/node/nodex/compact
3. via proactive compact
They can all be called proactive compaction.
Instead of indicate compaction is tirggerred by compact_memocy or anything,
order == -1 implies if compaction is triggerrred to meet allocation with high
order and we will stop compaction if allocation with target order will success.
IMO, the is_via_compact_memory() function helps people better
distinguish the compaction logic we have under direct compaction or
kcompactd compaction, while proactive compaction does not concern itself
with these details. But compaction_with_allocation_order() will make me
just wonder why we should compare with -1. So I don't think this patch
is worth it, but as you said above, we can add more comments to make it
more clear.
{
- return order == -1;
+ return order != -1;
}
/*
@@ -2200,7 +2199,7 @@ static enum compact_result __compact_finished(struct compact_control *cc)
goto out;
}
- if (is_via_compact_memory(cc->order))
+ if (!compaction_with_allocation_order(cc->order))
return COMPACT_CONTINUE;
/*
@@ -2390,7 +2389,7 @@ compact_zone(struct compact_control *cc, struct capture_control *capc)
cc->migratetype = gfp_migratetype(cc->gfp_mask);
- if (!is_via_compact_memory(cc->order)) {
+ if (compaction_with_allocation_order(cc->order)) {
unsigned long watermark;
/* Allocation can already succeed, nothing to do */
