From 4221aadd720bef7df1268391d6eb1ea1f0476b38 Mon Sep 17 00:00:00 2001 From: Bunyod Suvonov Date: Thu, 23 Apr 2026 18:37:53 +0800 Subject: mm/vmscan: add balance_pgdat begin/end tracepoints Vmscan has six main reclaim entry points: try_to_free_pages() for direct reclaim, try_to_free_mem_cgroup_pages() for memcg reclaim, mem_cgroup_shrink_node() for memcg soft limit reclaim, node_reclaim() for node reclaim, shrink_all_memory() for hibernation reclaim, and balance_pgdat() for kswapd reclaim. All of them, except for shrink_all_memory() and balance_pgdat(), already have begin/end tracepoints. This makes it harder to trace which reclaim path is responsible for memory reclaim activity, because kswapd reclaim cannot be identified as cleanly as other reclaim entry points, even though it is the main background reclaim path under memory pressure. There may be no need to trace shrink_all_memory() as it is primarily used during hibernation. So this patch adds the missing tracepoint pair for balance_pgdat(). The begin tracepoint records the node id, requested reclaim order, and the requested classzone bound (highest_zoneidx). The end tracepoint records the node id, the reclaim order that balance_pgdat() finished with, the requested classzone bound, and nr_reclaimed. Together, they show the requested reclaim order and classzone bound, whether reclaim fell back to a lower order, and how much reclaim work was done. The end tracepoint also records highest_zoneidx even though it does not change within a balance_pgdat() invocation. This keeps the end event self-contained, so users can analyze reclaim results directly from end events without depending on begin/end correlation, which is less convenient when tracing is filtered or records are dropped. It also makes it straightforward to relate nr_reclaimed and the final reclaim order to the requested classzone bound. Link: https://lore.kernel.org/20260424031418.174597-1-b.suvonov@sjtu.edu.cn Link: https://lore.kernel.org/20260423103753.546582-1-b.suvonov@sjtu.edu.cn Signed-off-by: Bunyod Suvonov Acked-by: Shakeel Butt Cc: Axel Rasmussen Cc: Barry Song Cc: David Hildenbrand Cc: Johannes Weiner Cc: Kairui Song Cc: Lorenzo Stoakes Cc: Masami Hiramatsu Cc: Mathieu Desnoyers Cc: Michal Hocko Cc: Qi Zheng Cc: Steven Rostedt Cc: Wei Xu Cc: Yuanchu Xie Signed-off-by: Andrew Morton --- include/trace/events/vmscan.h | 52 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 52 insertions(+) (limited to 'include/trace') diff --git a/include/trace/events/vmscan.h b/include/trace/events/vmscan.h index 4445a8d9218d..b4bf7b8def1f 100644 --- a/include/trace/events/vmscan.h +++ b/include/trace/events/vmscan.h @@ -96,6 +96,58 @@ TRACE_EVENT(mm_vmscan_kswapd_wake, __entry->order) ); +TRACE_EVENT(mm_vmscan_balance_pgdat_begin, + + TP_PROTO(int nid, int order, int highest_zoneidx), + + TP_ARGS(nid, order, highest_zoneidx), + + TP_STRUCT__entry( + __field(int, nid) + __field(int, order) + __field(int, highest_zoneidx) + ), + + TP_fast_assign( + __entry->nid = nid; + __entry->order = order; + __entry->highest_zoneidx = highest_zoneidx; + ), + + TP_printk("nid=%d order=%d highest_zoneidx=%-8s", + __entry->nid, + __entry->order, + __print_symbolic(__entry->highest_zoneidx, ZONE_TYPE)) +); + +TRACE_EVENT(mm_vmscan_balance_pgdat_end, + + TP_PROTO(int nid, int order, int highest_zoneidx, + unsigned long nr_reclaimed), + + TP_ARGS(nid, order, highest_zoneidx, nr_reclaimed), + + TP_STRUCT__entry( + __field(int, nid) + __field(int, order) + __field(int, highest_zoneidx) + __field(unsigned long, nr_reclaimed) + ), + + TP_fast_assign( + __entry->nid = nid; + __entry->order = order; + __entry->highest_zoneidx = highest_zoneidx; + __entry->nr_reclaimed = nr_reclaimed; + ), + + TP_printk("nid=%d order=%d highest_zoneidx=%-8s nr_reclaimed=%lu", + __entry->nid, + __entry->order, + __print_symbolic(__entry->highest_zoneidx, ZONE_TYPE), + __entry->nr_reclaimed) +); + TRACE_EVENT(mm_vmscan_wakeup_kswapd, TP_PROTO(int nid, int zid, int order, gfp_t gfp_flags), -- cgit v1.2.3 From b9b7bad279de29294c4d3314fe90fca345c38ea6 Mon Sep 17 00:00:00 2001 From: SeongJae Park Date: Mon, 18 May 2026 16:41:06 -0700 Subject: mm/damon: trace probe_hits Introduce a new tracepoint for exposing the per-region per-probe positive sample count via tracefs. Link: https://lore.kernel.org/20260518234119.97569-19-sj@kernel.org Signed-off-by: SeongJae Park Cc: David Hildenbrand Cc: Jonathan Corbet Cc: Liam R. Howlett Cc: Lorenzo Stoakes Cc: "Masami Hiramatsu (Google)" Cc: Mathieu Desnoyers Cc: Michal Hocko Cc: Mike Rapoport Cc: Shuah Khan Cc: Steven Rostedt Cc: Suren Baghdasaryan Cc: Vlastimil Babka Signed-off-by: Andrew Morton --- include/trace/events/damon.h | 38 ++++++++++++++++++++++++++++++++++++++ mm/damon/core.c | 9 +++++++++ 2 files changed, 47 insertions(+) (limited to 'include/trace') diff --git a/include/trace/events/damon.h b/include/trace/events/damon.h index 7e25f4469b81..78388538acf4 100644 --- a/include/trace/events/damon.h +++ b/include/trace/events/damon.h @@ -130,6 +130,44 @@ TRACE_EVENT(damon_monitor_intervals_tune, TP_printk("sample_us=%lu", __entry->sample_us) ); +TRACE_EVENT_CONDITION(damon_region_aggregated, + + TP_PROTO(unsigned int target_id, struct damon_region *r, + unsigned int nr_regions, unsigned int nr_probes), + + TP_ARGS(target_id, r, nr_regions, nr_probes), + + TP_CONDITION(nr_probes > 0), + + TP_STRUCT__entry( + __field(unsigned long, target_id) + __field(unsigned long, start) + __field(unsigned long, end) + __field(unsigned int, nr_regions) + __field(unsigned int, nr_accesses) + __field(unsigned int, age) + __dynamic_array(unsigned char, probe_hits, nr_probes) + ), + + TP_fast_assign( + __entry->target_id = target_id; + __entry->start = r->ar.start; + __entry->end = r->ar.end; + __entry->nr_regions = nr_regions; + __entry->nr_accesses = r->nr_accesses; + __entry->age = r->age; + memcpy(__get_dynamic_array(probe_hits), r->probe_hits, + sizeof(*r->probe_hits) * nr_probes); + ), + + TP_printk("target_id=%lu nr_regions=%u %lu-%lu: %u %u probe_hits=%s", + __entry->target_id, __entry->nr_regions, + __entry->start, __entry->end, + __entry->nr_accesses, __entry->age, + __print_hex(__get_dynamic_array(probe_hits), + __get_dynamic_array_len(probe_hits))) +); + TRACE_EVENT(damon_aggregated, TP_PROTO(unsigned int target_id, struct damon_region *r, diff --git a/mm/damon/core.c b/mm/damon/core.c index 500e8b08d441..903fd6fc9789 100644 --- a/mm/damon/core.c +++ b/mm/damon/core.c @@ -1905,6 +1905,13 @@ static void kdamond_reset_aggregated(struct damon_ctx *c) { struct damon_target *t; unsigned int ti = 0; /* target's index */ + unsigned int nr_probes = 0; + struct damon_probe *probe; + + if (trace_damon_region_aggregated_enabled()) { + damon_for_each_probe(probe, c) + nr_probes++; + } damon_for_each_target(t, c) { struct damon_region *r; @@ -1913,6 +1920,8 @@ static void kdamond_reset_aggregated(struct damon_ctx *c) int i; trace_damon_aggregated(ti, r, damon_nr_regions(t)); + trace_damon_region_aggregated(ti, r, + damon_nr_regions(t), nr_probes); damon_warn_fix_nr_accesses_corruption(r); r->last_nr_accesses = r->nr_accesses; r->nr_accesses = 0; -- cgit v1.2.3