From: Michal Hocko <mhocko@xxxxxxxx> Subject: mm, vmscan: add active list aging tracepoint Our reclaim process has several tracepoints to tell us more about how things are progressing. We are, however, missing a tracepoint to track active list aging. Introduce mm_vmscan_lru_shrink_active which reports the number of - nr_taken is number of isolated pages from the active list - nr_referenced pages which tells us that we are hitting referenced pages which are deactivated. If this is a large part of the reported nr_deactivated pages then we might be hitting into the active list too early because they might be still part of the working set. This might help to debug performance issues. - nr_active pages which tells us how many pages are kept on the active list - mostly exec file backed pages. A high number can indicate that we might be trashing on executables. [mhocko@xxxxxxxx: update] Link: http://lkml.kernel.org/r/20170104135244.GJ25453@xxxxxxxxxxxxxx Link: http://lkml.kernel.org/r/20170104101942.4860-3-mhocko@xxxxxxxxxx Signed-off-by: Michal Hocko <mhocko@xxxxxxxx> Acked-by: Hillf Danton <hillf.zj@xxxxxxxxxxxxxxx> Acked-by: Mel Gorman <mgorman@xxxxxxx> Acked-by: Minchan Kim <minchan@xxxxxxxxxx> Acked-by: Vlastimil Babka <vbabka@xxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- include/trace/events/vmscan.h | 36 ++++++++++++++++++++++++++++++++ mm/vmscan.c | 18 ++++++++++++---- 2 files changed, 50 insertions(+), 4 deletions(-) diff -puN include/trace/events/vmscan.h~mm-vmscan-add-active-list-aging-tracepoint include/trace/events/vmscan.h --- a/include/trace/events/vmscan.h~mm-vmscan-add-active-list-aging-tracepoint +++ a/include/trace/events/vmscan.h @@ -363,6 +363,42 @@ TRACE_EVENT(mm_vmscan_lru_shrink_inactiv show_reclaim_flags(__entry->reclaim_flags)) ); +TRACE_EVENT(mm_vmscan_lru_shrink_active, + + TP_PROTO(int nid, unsigned long nr_taken, + unsigned long nr_active, unsigned long nr_deactivated, + unsigned long nr_referenced, int priority, int file), + + TP_ARGS(nid, nr_taken, nr_active, nr_deactivated, nr_referenced, priority, file), + + TP_STRUCT__entry( + __field(int, nid) + __field(unsigned long, nr_taken) + __field(unsigned long, nr_active) + __field(unsigned long, nr_deactivated) + __field(unsigned long, nr_referenced) + __field(int, priority) + __field(int, reclaim_flags) + ), + + TP_fast_assign( + __entry->nid = nid; + __entry->nr_taken = nr_taken; + __entry->nr_active = nr_active; + __entry->nr_deactivated = nr_deactivated; + __entry->nr_referenced = nr_referenced; + __entry->priority = priority; + __entry->reclaim_flags = trace_shrink_flags(file); + ), + + TP_printk("nid=%d nr_taken=%ld nr_active=%ld nr_deactivated=%ld nr_referenced=%ld priority=%d flags=%s", + __entry->nid, + __entry->nr_taken, + __entry->nr_active, __entry->nr_deactivated, __entry->nr_referenced, + __entry->priority, + show_reclaim_flags(__entry->reclaim_flags)) +); + #endif /* _TRACE_VMSCAN_H */ /* This part must be outside protection */ diff -puN mm/vmscan.c~mm-vmscan-add-active-list-aging-tracepoint mm/vmscan.c --- a/mm/vmscan.c~mm-vmscan-add-active-list-aging-tracepoint +++ a/mm/vmscan.c @@ -1855,9 +1855,11 @@ shrink_inactive_list(unsigned long nr_to * * The downside is that we have to touch page->_refcount against each page. * But we had to alter page->flags anyway. + * + * Returns the number of pages moved to the given lru. */ -static void move_active_pages_to_lru(struct lruvec *lruvec, +static unsigned move_active_pages_to_lru(struct lruvec *lruvec, struct list_head *list, struct list_head *pages_to_free, enum lru_list lru) @@ -1866,6 +1868,7 @@ static void move_active_pages_to_lru(str unsigned long pgmoved = 0; struct page *page; int nr_pages; + int nr_moved = 0; while (!list_empty(list)) { page = lru_to_page(list); @@ -1891,11 +1894,15 @@ static void move_active_pages_to_lru(str spin_lock_irq(&pgdat->lru_lock); } else list_add(&page->lru, pages_to_free); + } else { + nr_moved += nr_pages; } } if (!is_active_lru(lru)) __count_vm_events(PGDEACTIVATE, pgmoved); + + return nr_moved; } static void shrink_active_list(unsigned long nr_to_scan, @@ -1911,7 +1918,8 @@ static void shrink_active_list(unsigned LIST_HEAD(l_inactive); struct page *page; struct zone_reclaim_stat *reclaim_stat = &lruvec->reclaim_stat; - unsigned long nr_rotated = 0; + unsigned nr_deactivate, nr_activate; + unsigned nr_rotated = 0; isolate_mode_t isolate_mode = 0; int file = is_file_lru(lru); struct pglist_data *pgdat = lruvec_pgdat(lruvec); @@ -1989,13 +1997,15 @@ static void shrink_active_list(unsigned */ reclaim_stat->recent_rotated[file] += nr_rotated; - move_active_pages_to_lru(lruvec, &l_active, &l_hold, lru); - move_active_pages_to_lru(lruvec, &l_inactive, &l_hold, lru - LRU_ACTIVE); + nr_activate = move_active_pages_to_lru(lruvec, &l_active, &l_hold, lru); + nr_deactivate = move_active_pages_to_lru(lruvec, &l_inactive, &l_hold, lru - LRU_ACTIVE); __mod_node_page_state(pgdat, NR_ISOLATED_ANON + file, -nr_taken); spin_unlock_irq(&pgdat->lru_lock); mem_cgroup_uncharge_list(&l_hold); free_hot_cold_page_list(&l_hold, true); + trace_mm_vmscan_lru_shrink_active(pgdat->node_id, nr_taken, nr_activate, + nr_deactivate, nr_rotated, sc->priority, file); } /* _ -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
