[PATCH v2] vmscan: add trace events for lru_gen
From: Jaewon Kim
Date: Thu Sep 21 2023 - 13:02:25 EST
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
Here's an example
mm_vmscan_lru_gen_scan: isolate_mode=0 classzone=1 order=9 nr_requested=4096 nr_scanned=431 nr_skipped=0 nr_taken=55 lru=anon
mm_vmscan_lru_gen_evict: nid=0 nr_reclaimed=42 nr_dirty=0 nr_writeback=0 nr_congested=0 nr_immediate=0 nr_activate_anon=13 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: isolate_mode=0 classzone=1 order=9 nr_requested=4096 nr_scanned=66 nr_skipped=0 nr_taken=64 lru=file
mm_vmscan_lru_gen_evict: nid=0 nr_reclaimed=62 nr_dirty=0 nr_writeback=0 nr_congested=0 nr_immediate=0 nr_activate_anon=0 nr_activate_file=2 nr_ref_keep=0 nr_unmap_fail=0 priority=2 flags=RECLAIM_WB_FILE|RECLAIM_WB_ASYNC
Signed-off-by: Jaewon Kim <jaewon31.kim@xxxxxxxxxxx>
---
v2: use condition and make it aligned
v1: introduce trace events
---
include/trace/events/mmflags.h | 5 ++
include/trace/events/vmscan.h | 98 ++++++++++++++++++++++++++++++++++
mm/vmscan.c | 17 ++++--
3 files changed, 115 insertions(+), 5 deletions(-)
diff --git a/include/trace/events/mmflags.h b/include/trace/events/mmflags.h
index 1478b9dd05fa..44e9b38f83e7 100644
--- a/include/trace/events/mmflags.h
+++ b/include/trace/events/mmflags.h
@@ -274,6 +274,10 @@ IF_HAVE_VM_SOFTDIRTY(VM_SOFTDIRTY, "softdirty" ) \
EM (LRU_ACTIVE_FILE, "active_file") \
EMe(LRU_UNEVICTABLE, "unevictable")
+#define LRU_GEN_NAMES \
+ EM (LRU_GEN_ANON, "anon") \
+ EMe(LRU_GEN_FILE, "file")
+
/*
* First define the enums in the above macros to be exported to userspace
* via TRACE_DEFINE_ENUM().
@@ -288,6 +292,7 @@ COMPACTION_PRIORITY
/* COMPACTION_FEEDBACK are defines not enums. Not needed here. */
ZONE_TYPE
LRU_NAMES
+LRU_GEN_NAMES
/*
* 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..f0c3a4bd72db 100644
--- a/include/trace/events/vmscan.h
+++ b/include/trace/events/vmscan.h
@@ -327,6 +327,57 @@ TRACE_EVENT(mm_vmscan_lru_isolate,
__print_symbolic(__entry->lru, LRU_NAMES))
);
+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,
+ isolate_mode_t isolate_mode,
+ int lru),
+
+ TP_ARGS(highest_zoneidx, order, nr_requested, nr_scanned, nr_skipped, nr_taken, isolate_mode, 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(unsigned int, isolate_mode)
+ __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->isolate_mode = (__force unsigned int)isolate_mode;
+ __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("isolate_mode=%d classzone=%d order=%d nr_requested=%lu nr_scanned=%lu nr_skipped=%lu nr_taken=%lu lru=%s",
+ __entry->isolate_mode,
+ __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_write_folio,
TP_PROTO(struct folio *folio),
@@ -437,6 +488,53 @@ TRACE_EVENT(mm_vmscan_lru_shrink_active,
show_reclaim_flags(__entry->reclaim_flags))
);
+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=%ld nr_dirty=%ld nr_writeback=%ld nr_congested=%ld nr_immediate=%ld nr_activate_anon=%d nr_activate_file=%d nr_ref_keep=%ld nr_unmap_fail=%ld 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))
+);
+
TRACE_EVENT(mm_vmscan_node_reclaim_begin,
TP_PROTO(int nid, int order, gfp_t gfp_flags),
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 6f13394b112e..f453a0f8ceef 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 +5067,9 @@ static int scan_folios(struct lruvec *lruvec, struct scan_control *sc,
__count_memcg_events(memcg, PGREFILL, sorted);
__count_vm_events(PGSCAN_ANON + type, isolated);
+ trace_mm_vmscan_lru_gen_scan(sc->reclaim_idx, sc->order, MAX_LRU_BATCH,
+ scanned, skipped, isolated,
+ sc->may_unmap ? 0 : ISOLATE_UNMAPPED, type);
/*
* There might not be eligible folios due to reclaim_idx. Check the
* remaining to prevent livelock if it's not making progress.
@@ -5194,6 +5199,8 @@ 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;
+ trace_mm_vmscan_lru_gen_evict(pgdat->node_id, reclaimed, &stat,
+ sc->priority, type);
list_for_each_entry_safe_reverse(folio, next, &list, lru) {
if (!folio_evictable(folio)) {
--
2.17.1