2023-05-25 12:55:39

by Baolin Wang

Subject: [PATCH 5/6] mm: compaction: add trace event for fast freepages isolation

The fast_isolate_freepages() can also isolate freepages, but we can not
know the fast isolation efficiency to understand the fast isolation pressure.
So add a trace event to show some numbers to help to understand the efficiency
for fast freepages isolation.

Signed-off-by: Baolin Wang <[email protected]>
---
include/trace/events/compaction.h | 11 +++++++++++
mm/compaction.c | 6 +++++-
2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/include/trace/events/compaction.h b/include/trace/events/compaction.h
index 3313eb83c117..2b2a975efd20 100644
--- a/include/trace/events/compaction.h
+++ b/include/trace/events/compaction.h
@@ -64,6 +64,17 @@ DEFINE_EVENT(mm_compaction_isolate_template, mm_compaction_isolate_freepages,
TP_ARGS(start_pfn, end_pfn, nr_scanned, nr_taken)
);

+DEFINE_EVENT(mm_compaction_isolate_template, mm_compaction_fast_isolate_freepages,
+
+ TP_PROTO(
+ unsigned long start_pfn,
+ unsigned long end_pfn,
+ unsigned long nr_scanned,
+ unsigned long nr_taken),
+
+ TP_ARGS(start_pfn, end_pfn, nr_scanned, nr_taken)
+);
+
#ifdef CONFIG_COMPACTION
TRACE_EVENT(mm_compaction_migratepages,

diff --git a/mm/compaction.c b/mm/compaction.c
index 65d8d9223acc..eccec84dae82 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -1438,7 +1438,7 @@ static int next_search_order(struct compact_control *cc, int order)
static void fast_isolate_freepages(struct compact_control *cc)
{
unsigned int limit = max(1U, freelist_scan_limit(cc) >> 1);
- unsigned int nr_scanned = 0;
+ unsigned int nr_scanned = 0, total_isolated = 0;
unsigned long low_pfn, min_pfn, highest = 0;
unsigned long nr_isolated = 0;
unsigned long distance;
@@ -1537,6 +1537,7 @@ static void fast_isolate_freepages(struct compact_control *cc)
set_page_private(page, order);
nr_isolated = 1 << order;
nr_scanned += nr_isolated - 1;
+ total_isolated += nr_isolated;
cc->nr_freepages += nr_isolated;
list_add_tail(&page->lru, &cc->freepages);
count_compact_events(COMPACTISOLATED, nr_isolated);
@@ -1557,6 +1558,9 @@ static void fast_isolate_freepages(struct compact_control *cc)
limit = max(1U, limit >> 1);
}

+ trace_mm_compaction_fast_isolate_freepages(min_pfn, cc->free_pfn,
+ nr_scanned, total_isolated);
+
if (!page) {
cc->fast_search_fail++;
if (scan_start) {
--
2.27.0

2023-05-30 08:49:11

by Vlastimil Babka

Subject: Re: [PATCH 5/6] mm: compaction: add trace event for fast freepages isolation

On 5/25/23 14:54, Baolin Wang wrote:
> The fast_isolate_freepages() can also isolate freepages, but we can not
> know the fast isolation efficiency to understand the fast isolation pressure.
> So add a trace event to show some numbers to help to understand the efficiency
> for fast freepages isolation.
>
> Signed-off-by: Baolin Wang <[email protected]>

Acked-by: Vlastimil Babka <[email protected]>