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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>
hifive-unleashed-5.1
Michal Hocko 2017-02-22 15:44:18 -08:00 committed by Linus Torvalds
parent 30b9aed8cd
commit 9d998b4f1e
2 changed files with 50 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

36
include/trace/events/vmscan.h
View File

@ -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 */

18
mm/vmscan.c
View File

@ -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);
}
/*