When the system memory is low, kswapd reclaims the memory. The key steps of memory reclamation include 1.shrink_lruvec * shrink_active_list, moves folios from the active LRU to the inactive LRU * shrink_inactive_list, shrink lru from inactive LRU list 2.shrink_slab * shrinker->count_objects(), calculates the freeable memory * shrinker->scan_objects(), reclaims the slab memory The existing tracers in the vmscan are as follows: --do_try_to_free_pages --shrink_zones --trace_mm_vmscan_node_reclaim_begin (tracer) --shrink_node --shrink_node_memcgs --trace_mm_vmscan_memcg_shrink_begin (tracer) --shrink_lruvec --shrink_list --shrink_active_list --trace_mm_vmscan_lru_shrink_active (tracer) --shrink_inactive_list --trace_mm_vmscan_lru_shrink_inactive (tracer) --shrink_active_list --shrink_slab --do_shrink_slab --shrinker->count_objects() --trace_mm_shrink_slab_start (tracer) --shrinker->scan_objects() --trace_mm_shrink_slab_end (tracer) --trace_mm_vmscan_memcg_shrink_end (tracer) --trace_mm_vmscan_node_reclaim_end (tracer) If we get the duration and quantity of shrink lru and slab, then we can measure the memory recycling, as follows Measuring memory reclamation with bpf: LRU FILE: CPU COMM ShrinkActive(us) ShrinkInactive(us) Reclaim(page) 7 kswapd0 26 51 32 7 kswapd0 52 47 13 SLAB: CPU COMM OBJ_NAME Count_Dur(us) Freeable(page) Scan_Dur(us) Reclaim(page) 1 kswapd0 super_cache_scan.cfi_jt 2 341 3225 128 7 kswapd0 super_cache_scan.cfi_jt 0 2247 8524 1024 7 kswapd0 super_cache_scan.cfi_jt 2367 0 0 0 For this, add the new tracer to shrink_active_list/shrink_inactive_list and shrinker->count_objects(). Changes: v4: Add Reviewed-by and Changlog to every patch. v3: Swap the positions of 'nid' and 'freeable' to prevent the hole in the trace event. v2: Modify trace_mm_vmscan_lru_shrink_inactive() in evict_folios() at the same time to fix build error. cuibixuan (2): mm: shrinker: add new event to trace shrink count mm: vmscan: add new event to trace shrink lru include/trace/events/vmscan.h | 87 ++++++++++++++++++++++++++++++++++- mm/shrinker.c | 4 ++ mm/vmscan.c | 11 +++-- 3 files changed, 97 insertions(+), 5 deletions(-) -- 2.17.1