mm, vmscan: show the number of skipped pages in mm_vmscan_lru_isolate
mm_vmscan_lru_isolate shows the number of requested, scanned and taken
pages. This is mostly OK but on 32b systems the number of scanned pages
is quite misleading because it includes both the scanned and skipped
pages. Moreover the skipped part is scaled based on the number of taken
pages. Let's report the exact numbers without any additional logic and
add the number of skipped pages.
This should make the reported data much more easier to interpret.
Change-Id: Ic98a1c2bf442b8c53041d0d3b0c10010abb7adb2
Link: http://lkml.kernel.org/r/20170104101942.4860-4-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Acked-by: Mel Gorman <mgorman@suse.de>
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>
Git-commit: 1265e3a69f1ea97357536773d48c92a409e01eaf
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
Signed-off-by: Vinayak Menon <vinmenon@codeaurora.org>
diff --git a/mm/vmscan.c b/mm/vmscan.c
index d20773b..2d07129 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1508,6 +1508,7 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan,
unsigned long nr_taken = 0;
unsigned long nr_zone_taken[MAX_NR_ZONES] = { 0 };
unsigned long nr_skipped[MAX_NR_ZONES] = { 0, };
+ unsigned long skipped = 0, total_skipped = 0;
unsigned long scan, nr_pages;
LIST_HEAD(pages_skipped);
@@ -1559,14 +1560,13 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan,
*/
if (!list_empty(&pages_skipped)) {
int zid;
- unsigned long total_skipped = 0;
for (zid = 0; zid < MAX_NR_ZONES; zid++) {
if (!nr_skipped[zid])
continue;
__count_zid_vm_events(PGSCAN_SKIP, zid, nr_skipped[zid]);
- total_skipped += nr_skipped[zid];
+ skipped += nr_skipped[zid];
}
/*
@@ -1574,13 +1574,14 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan,
* close to unreclaimable. If the LRU list is empty, account
* skipped pages as a full scan.
*/
- scan += list_empty(src) ? total_skipped : total_skipped >> 2;
+ total_skipped = list_empty(src) ? skipped : skipped >> 2;
list_splice(&pages_skipped, src);
}
- *nr_scanned = scan;
- trace_mm_vmscan_lru_isolate(sc->reclaim_idx, sc->order, nr_to_scan, scan,
- nr_taken, mode, is_file_lru(lru));
+ *nr_scanned = scan + total_skipped;
+ trace_mm_vmscan_lru_isolate(sc->reclaim_idx, sc->order, nr_to_scan,
+ scan, skipped, nr_taken, mode,
+ is_file_lru(lru));
update_lru_sizes(lruvec, lru, nr_zone_taken);
return nr_taken;
}