From: Ridong Chen <[email protected]> MGLRU's scan_folios() emits the classic-LRU tracepoint trace_mm_vmscan_lru_isolate(), which predates MGLRU. It reports the scan/isolate counts and the LRU type, but carries no generation or memcg context, so a trace of an MGLRU run cannot tell which memcg a given scan belongs to, nor how far reclaim has progressed through the generations.
Add mm_mglru_scan_folios next to it, reporting the same counters plus nr_sorted (folios moved to a younger generation by sort_folio()) and the MGLRU context the classic tracepoint lacks: the memcg id, and the max_seq, tier and min_seq of the type being scanned. scan_folios() is the MGLRU-specific layer where folios are actually scanned, so it has no classic-LRU counterpart. That the classic trace_mm_vmscan_lru_isolate() has lived here stably shows this is a long-lived place to hook, and the new tracepoint can be enabled on its own to observe the MGLRU-specific information. The existing tracepoint is left unchanged. Assisted-by: Claude:claude-opus-4-8 Signed-off-by: Ridong Chen <[email protected]> --- include/trace/events/vmscan.h | 63 +++++++++++++++++++++++++++++++++++ mm/vmscan.c | 6 ++++ 2 files changed, 69 insertions(+) diff --git a/include/trace/events/vmscan.h b/include/trace/events/vmscan.h index 8a872990b4be..c39dfacef033 100644 --- a/include/trace/events/vmscan.h +++ b/include/trace/events/vmscan.h @@ -392,6 +392,69 @@ TRACE_EVENT(mm_vmscan_lru_isolate, __print_symbolic(__entry->lru, LRU_NAMES)) ); +TRACE_EVENT(mm_mglru_scan_folios, + + TP_PROTO(u64 memcg_id, + int highest_zoneidx, + int order, + unsigned long nr_requested, + unsigned long nr_scanned, + unsigned long nr_sorted, + unsigned long nr_skipped, + unsigned long nr_taken, + int lru, + unsigned long max_seq, + int tier, + unsigned long min_seq), + + TP_ARGS(memcg_id, highest_zoneidx, order, nr_requested, nr_scanned, + nr_sorted, nr_skipped, nr_taken, lru, max_seq, tier, min_seq), + + TP_STRUCT__entry( + __field(u64, memcg_id) + __field(int, highest_zoneidx) + __field(int, order) + __field(unsigned long, nr_requested) + __field(unsigned long, nr_scanned) + __field(unsigned long, nr_sorted) + __field(unsigned long, nr_skipped) + __field(unsigned long, nr_taken) + __field(int, lru) + __field(unsigned long, max_seq) + __field(int, tier) + __field(unsigned long, min_seq) + ), + + TP_fast_assign( + __entry->memcg_id = memcg_id; + __entry->highest_zoneidx = highest_zoneidx; + __entry->order = order; + __entry->nr_requested = nr_requested; + __entry->nr_scanned = nr_scanned; + __entry->nr_sorted = nr_sorted; + __entry->nr_skipped = nr_skipped; + __entry->nr_taken = nr_taken; + __entry->lru = lru; + __entry->max_seq = max_seq; + __entry->tier = tier; + __entry->min_seq = min_seq; + ), + + TP_printk("memcg_id=%llu classzone=%d order=%d nr_requested=%lu nr_scanned=%lu nr_sorted=%lu nr_skipped=%lu nr_taken=%lu lru=%s max_seq=%lu tier=%d min_seq=%lu", + __entry->memcg_id, + __entry->highest_zoneidx, + __entry->order, + __entry->nr_requested, + __entry->nr_scanned, + __entry->nr_sorted, + __entry->nr_skipped, + __entry->nr_taken, + __print_symbolic(__entry->lru, LRU_NAMES), + __entry->max_seq, + __entry->tier, + __entry->min_seq) +); + TRACE_EVENT(mm_vmscan_write_folio, TP_PROTO(struct folio *folio), diff --git a/mm/vmscan.c b/mm/vmscan.c index 2554a6513aa8..bd1b9ecf2e84 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -4876,6 +4876,12 @@ static int scan_folios(unsigned long nr_to_scan, struct lruvec *lruvec, trace_mm_vmscan_lru_isolate(sc->reclaim_idx, sc->order, nr_to_scan, scanned, skipped, isolated, type ? LRU_INACTIVE_FILE : LRU_INACTIVE_ANON); + trace_mm_mglru_scan_folios(mem_cgroup_id(lruvec_memcg(lruvec)), + sc->reclaim_idx, sc->order, nr_to_scan, + scanned, sorted, skipped, isolated, + type ? LRU_INACTIVE_FILE : LRU_INACTIVE_ANON, + lrugen->max_seq, tier, + lrugen->min_seq[type]); *isolatedp = isolated; return scanned; -- 2.34.1
