On 09/15/26 at 08:17pm, Ridong Chen wrote:
>
>
> On 9/15/2026 7:14 PM, Baoquan He wrote:
> > On 09/11/26 at 06:29pm, Ridong Chen wrote:
> > > From: Ridong Chen <[email protected]>
> > ...snip...
> > > ---
> > > 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..5defa8f6719c 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(struct lruvec *lruvec,
> > > + 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),
> >
>
> Thank you for your review.
>
> > Do we need show nid? Guess phone vendor doesn't care about multi-NUMA
> > system.
> >
>
> Eh, nid is not an mglru-specific key. Since there are 12 elements here, it
> can't be added here.
Hmm, we print memcg_id but not nid, it may not be so clear. How do you
differentiate several lruvec-s on one memcg? I am not very familiar with
trace mechanism, do we have a element number limit?
Imagine I only want to trace this function, now I can see memcg_id,
zone_idex, while don't know node/lruvec, that's a little pitty. Just my
personal opinion, I could miss anything.
>
>
> > And I checked v1 thread, seems Steven suggested to move the two int to
> > avoid extra padding.
> >
>
> Yeah, I will update it. I updated v2 to fix Sashiko's issue, before Steven
> had any comment.
>
>
> > > +
> > > + TP_ARGS(lruvec, 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 = mem_cgroup_id(lruvec_memcg(lruvec));
> > > + __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..67f59aa73fb9 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(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]);
> >
> > And seems Steven also suggested to calculate lru, max_seq, min_seq in
> > TP_fast_assign() in v1 which could be missed.
> >
>
> Thanks, I will update it following Steven's suggestions.
>
>
> > TP_fast_assign(
> > __entry->memcg_id = mem_cgroup_id(lruvec_memcg(lruvec));
> > __entry->highest_zoneidx = sc->reclaim_idx;
> > __entry->order = sc->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 = type ? LRU_INACTIVE_FILE :
> > LRU_INACTIVE_ANON;
> > __entry->max_seq = lrugen->max_seq;
> > __entry->tier = tier;
> > __entry->min_seq = lrugen->min_seq;
> > ),
> >
>
> However, 'sc' is an internal structure, so sc->order cannot be accessed in
> TP_fast_assign(), and I don't think it is worth making scan_control an
> external structure just for this.
Agree.
>
> >
> > > *isolatedp = isolated;
> > > return scanned;
> > > --
> > > 2.34.1
> > >
>
> --
> Best regards
> Ridong
>
