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authorMichal Hocko <mhocko@suse.com>2017-02-22 15:44:18 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2017-02-22 16:41:29 -0800
commit9d998b4f1e39abd69441d29a1ef3250514479267 (patch)
treecee0abd3ba3d05102fd4afb9b233623f2e9adf57
parent30b9aed8cd576964bff71a6c5f022ca30ac4c3b7 (diff)
downloadlinux-9d998b4f1e39abd69441d29a1ef3250514479267.tar.bz2
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@suse.com: update] Link: http://lkml.kernel.org/r/20170104135244.GJ25453@dhcp22.suse.cz Link: http://lkml.kernel.org/r/20170104101942.4860-3-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Acked-by: Hillf Danton <hillf.zj@alibaba-inc.com> Acked-by: Mel Gorman <mgorman@suse.de> Acked-by: Minchan Kim <minchan@kernel.org> Acked-by: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--include/trace/events/vmscan.h36
-rw-r--r--mm/vmscan.c18
2 files changed, 50 insertions, 4 deletions
diff --git a/include/trace/events/vmscan.h b/include/trace/events/vmscan.h
index 39bad8921ca1..c295d8f1b67a 100644
--- a/include/trace/events/vmscan.h
+++ b/include/trace/events/vmscan.h
@@ -363,6 +363,42 @@ TRACE_EVENT(mm_vmscan_lru_shrink_inactive,
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 --git a/mm/vmscan.c b/mm/vmscan.c
index 532a2a750952..a34bf51d68e2 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1855,9 +1855,11 @@ shrink_inactive_list(unsigned long nr_to_scan, struct lruvec *lruvec,
*
* 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(struct lruvec *lruvec,
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(struct lruvec *lruvec,
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 long nr_to_scan,
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 long nr_to_scan,
*/
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);
}
/*