RE: [PATCH v4] vmscan: add trace events for lru_gen

From: 김재원
Date: Tue Sep 26 2023 - 01:11:02 EST

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>On Mon, Sep 25, 2023 at 10:20?PM Jaewon Kim <jaewon31.kim@xxxxxxxxxxx> wrote:
>>
>> As the legacy lru provides, the lru_gen needs some trace events for
>> debugging.
>>
>> This commit introduces 2 trace events.
>> trace_mm_vmscan_lru_gen_scan
>> trace_mm_vmscan_lru_gen_evict
>>
>> Each event is similar to the following legacy events.
>> trace_mm_vmscan_lru_isolate,
>> trace_mm_vmscan_lru_shrink_[in]active
>
>We should just reuse trace_mm_vmscan_lru_isolate and
>trace_mm_vmscan_lru_shrink_inactive instead of adding new tracepoints.
>
>To reuse trace_mm_vmscan_lru_isolate, we'd just need to append two new
>names to LRU_NAMES.
>
>The naming of trace_mm_vmscan_lru_shrink_inactive might seem confusing
>but it's how MGLRU maintains the compatibility, e.g., the existing
>active/inactive counters in /proc/vmstat.

Hello

Actually I had tried to reuse them. But some value was not that compatible.
Let me try that way again.

>
>> Here's an example
>> mm_vmscan_lru_gen_scan: classzone=2 order=0 nr_requested=4096 nr_scanned=64 nr_skipped=0 nr_taken=64 lru=anon
>> mm_vmscan_lru_gen_evict: nid=0 nr_reclaimed=64 nr_dirty=0 nr_writeback=0 nr_congested=0 nr_immediate=0 nr_activate_anon=0 nr_activate_file=0 nr_ref_keep=0 nr_unmap_fail=0 priority=2 flags=RECLAIM_WB_ANON|RECLAIM_WB_ASYNC
>> mm_vmscan_lru_gen_scan: classzone=1 order=0 nr_requested=4096 nr_scanned=64 nr_skipped=0 nr_taken=64 lru=file
>> mm_vmscan_lru_gen_evict: nid=0 nr_reclaimed=64 nr_dirty=0 nr_writeback=0 nr_congested=0 nr_immediate=0 nr_activate_anon=0 nr_activate_file=0 nr_ref_keep=0 nr_unmap_fail=0 priority=12 flags=RECLAIM_WB_FILE|RECLAIM_WB_ASYNC
>>
>> Signed-off-by: Jaewon Kim <jaewon31.kim@xxxxxxxxxxx>
>> ---
>> v4: wrap with #ifdef CONFIG_LRU_GEN
>> v3: change printk format
>> v2: use condition and make it aligned
>> v1: introduce trace events
>> ---
>> include/trace/events/mmflags.h | 9 ++++
>> include/trace/events/vmscan.h | 96 ++++++++++++++++++++++++++++++++++
>> mm/vmscan.c | 20 +++++--
>> 3 files changed, 120 insertions(+), 5 deletions(-)
>>
>> diff --git a/include/trace/events/mmflags.h b/include/trace/events/mmflags.h
>> index 1478b9dd05fa..6dfe85bd4e81 100644
>> --- a/include/trace/events/mmflags.h
>> +++ b/include/trace/events/mmflags.h
>> @@ -274,6 +274,12 @@ IF_HAVE_VM_SOFTDIRTY(VM_SOFTDIRTY, "softdirty" ) \
>> EM (LRU_ACTIVE_FILE, "active_file") \
>> EMe(LRU_UNEVICTABLE, "unevictable")
>>
>> +#ifdef CONFIG_LRU_GEN
>> +#define LRU_GEN_NAMES \
>> + EM (LRU_GEN_ANON, "anon") \
>> + EMe(LRU_GEN_FILE, "file")
>> +#endif
>> +
>> /*
>> * First define the enums in the above macros to be exported to userspace
>> * via TRACE_DEFINE_ENUM().
>> @@ -288,6 +294,9 @@ COMPACTION_PRIORITY
>> /* COMPACTION_FEEDBACK are defines not enums. Not needed here. */
>> ZONE_TYPE
>> LRU_NAMES
>> +#ifdef CONFIG_LRU_GEN
>> +LRU_GEN_NAMES
>> +#endif
>>
>> /*
>> * Now redefine the EM() and EMe() macros to map the enums to the strings
>> diff --git a/include/trace/events/vmscan.h b/include/trace/events/vmscan.h
>> index d2123dd960d5..2080ef742f89 100644
>> --- a/include/trace/events/vmscan.h
>> +++ b/include/trace/events/vmscan.h
>> @@ -327,6 +327,102 @@ TRACE_EVENT(mm_vmscan_lru_isolate,
>> __print_symbolic(__entry->lru, LRU_NAMES))
>> );
>>
>> +#ifdef CONFIG_LRU_GEN
>> +TRACE_EVENT_CONDITION(mm_vmscan_lru_gen_scan,
>> + TP_PROTO(int highest_zoneidx,
>> + int order,
>> + unsigned long nr_requested,
>> + unsigned long nr_scanned,
>> + unsigned long nr_skipped,
>> + unsigned long nr_taken,
>> + int lru),
>> +
>> + TP_ARGS(highest_zoneidx, order, nr_requested, nr_scanned, nr_skipped, nr_taken, lru),
>> +
>> + TP_CONDITION(nr_scanned),
>> +
>> + TP_STRUCT__entry(
>> + __field(int, highest_zoneidx)
>> + __field(int, order)
>> + __field(unsigned long, nr_requested)
>> + __field(unsigned long, nr_scanned)
>> + __field(unsigned long, nr_skipped)
>> + __field(unsigned long, nr_taken)
>> + __field(int, lru)
>> + ),
>> +
>> + TP_fast_assign(
>> + __entry->highest_zoneidx = highest_zoneidx;
>> + __entry->order = order;
>> + __entry->nr_requested = nr_requested;
>> + __entry->nr_scanned = nr_scanned;
>> + __entry->nr_skipped = nr_skipped;
>> + __entry->nr_taken = nr_taken;
>> + __entry->lru = lru;
>> + ),
>> +
>> + /*
>> + * classzone is previous name of the highest_zoneidx.
>> + * Reason not to change it is the ABI requirement of the tracepoint.
>> + */
>> + TP_printk("classzone=%d order=%d nr_requested=%lu nr_scanned=%lu nr_skipped=%lu nr_taken=%lu lru=%s",
>> + __entry->highest_zoneidx,
>> + __entry->order,
>> + __entry->nr_requested,
>> + __entry->nr_scanned,
>> + __entry->nr_skipped,
>> + __entry->nr_taken,
>> + __print_symbolic(__entry->lru, LRU_GEN_NAMES))
>> +);
>> +
>> +TRACE_EVENT(mm_vmscan_lru_gen_evict,
>> +
>> + TP_PROTO(int nid, unsigned long nr_reclaimed,
>> + struct reclaim_stat *stat, int priority, int file),
>> +
>> + TP_ARGS(nid, nr_reclaimed, stat, priority, file),
>> +
>> + TP_STRUCT__entry(
>> + __field(unsigned long, nr_reclaimed)
>> + __field(unsigned long, nr_dirty)
>> + __field(unsigned long, nr_writeback)
>> + __field(unsigned long, nr_congested)
>> + __field(unsigned long, nr_immediate)
>> + __field(unsigned int, nr_activate0)
>> + __field(unsigned int, nr_activate1)
>> + __field(unsigned long, nr_ref_keep)
>> + __field(unsigned long, nr_unmap_fail)
>> + __field(int, nid)
>> + __field(int, priority)
>> + __field(int, reclaim_flags)
>> + ),
>> +
>> + TP_fast_assign(
>> + __entry->nid = nid;
>> + __entry->nr_reclaimed = nr_reclaimed;
>> + __entry->nr_dirty = stat->nr_dirty;
>> + __entry->nr_writeback = stat->nr_writeback;
>> + __entry->nr_congested = stat->nr_congested;
>> + __entry->nr_immediate = stat->nr_immediate;
>> + __entry->nr_activate0 = stat->nr_activate[0];
>> + __entry->nr_activate1 = stat->nr_activate[1];
>> + __entry->nr_ref_keep = stat->nr_ref_keep;
>> + __entry->nr_unmap_fail = stat->nr_unmap_fail;
>> + __entry->priority = priority;
>> + __entry->reclaim_flags = trace_reclaim_flags(file);
>> + ),
>> +
>> + TP_printk("nid=%d nr_reclaimed=%lu nr_dirty=%lu nr_writeback=%lu nr_congested=%lu nr_immediate=%lu nr_activate_anon=%u nr_activate_file=%u nr_ref_keep=%lu nr_unmap_fail=%lu priority=%d flags=%s",
>> + __entry->nid, __entry->nr_reclaimed,
>> + __entry->nr_dirty, __entry->nr_writeback,
>> + __entry->nr_congested, __entry->nr_immediate,
>> + __entry->nr_activate0, __entry->nr_activate1,
>> + __entry->nr_ref_keep, __entry->nr_unmap_fail,
>> + __entry->priority,
>> + show_reclaim_flags(__entry->reclaim_flags))
>> +);
>> +#endif
>> +
>> TRACE_EVENT(mm_vmscan_write_folio,
>>
>> TP_PROTO(struct folio *folio),
>> diff --git a/mm/vmscan.c b/mm/vmscan.c
>> index 6f13394b112e..0c8b48bcb461 100644
>> --- a/mm/vmscan.c
>> +++ b/mm/vmscan.c
>> @@ -5005,6 +5005,7 @@ static int scan_folios(struct lruvec *lruvec, struct scan_control *sc,
>> int sorted = 0;
>> int scanned = 0;
>> int isolated = 0;
>> + int skipped = 0;
>> int remaining = MAX_LRU_BATCH;
>> struct lru_gen_folio *lrugen = &lruvec->lrugen;
>> struct mem_cgroup *memcg = lruvec_memcg(lruvec);
>> @@ -5018,7 +5019,7 @@ static int scan_folios(struct lruvec *lruvec, struct scan_control *sc,
>>
>> for (i = MAX_NR_ZONES; i > 0; i--) {
>> LIST_HEAD(moved);
>> - int skipped = 0;
>> + int skipped_zone = 0;
>> int zone = (sc->reclaim_idx + i) % MAX_NR_ZONES;
>> struct list_head *head = &lrugen->folios[gen][type][zone];
>>
>> @@ -5040,16 +5041,17 @@ static int scan_folios(struct lruvec *lruvec, struct scan_control *sc,
>> isolated += delta;
>> } else {
>> list_move(&folio->lru, &moved);
>> - skipped += delta;
>> + skipped_zone += delta;
>> }
>>
>> - if (!--remaining || max(isolated, skipped) >= MIN_LRU_BATCH)
>> + if (!--remaining || max(isolated, skipped_zone) >= MIN_LRU_BATCH)
>> break;
>> }
>>
>> - if (skipped) {
>> + if (skipped_zone) {
>> list_splice(&moved, head);
>> - __count_zid_vm_events(PGSCAN_SKIP, zone, skipped);
>> + __count_zid_vm_events(PGSCAN_SKIP, zone, skipped_zone);
>> + skipped += skipped_zone;
>> }
>>
>> if (!remaining || isolated >= MIN_LRU_BATCH)
>> @@ -5065,6 +5067,10 @@ static int scan_folios(struct lruvec *lruvec, struct scan_control *sc,
>> __count_memcg_events(memcg, PGREFILL, sorted);
>> __count_vm_events(PGSCAN_ANON + type, isolated);
>>
>> +#ifdef CONFIG_LRU_GEN
>> + trace_mm_vmscan_lru_gen_scan(sc->reclaim_idx, sc->order, MAX_LRU_BATCH,
>> + scanned, skipped, isolated, type);
>> +#endif
>
>These functions are already within CONFIG_LRU_GEN.
>
>> /*
>> * There might not be eligible folios due to reclaim_idx. Check the
>> * remaining to prevent livelock if it's not making progress.
>> @@ -5194,6 +5200,10 @@ static int evict_folios(struct lruvec *lruvec, struct scan_control *sc, int swap
>> retry:
>> reclaimed = shrink_folio_list(&list, pgdat, sc, &stat, false);
>> sc->nr_reclaimed += reclaimed;
>> +#ifdef CONFIG_LRU_GEN
>> + trace_mm_vmscan_lru_gen_evict(pgdat->node_id, reclaimed, &stat,
>> + sc->priority, type);
>> +#endif
>
>Ditto.

Next message: Chen Yu: "[PATCH 0/2] Introduce SIS_CACHE to choose previous CPU during task wakeup"
Previous message: Amir Goldstein: "Re: linux-next: manual merge of the vfs-brauner tree with the overlayfs tree"
In reply to: Yu Zhao: "Re: [PATCH v4] vmscan: add trace events for lru_gen"
Next in thread: 김재원: "RE: [PATCH v4] vmscan: add trace events for lru_gen"
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