From: Michal Hocko Date: Wed, 22 Feb 2017 23:44:21 +0000 (-0800) Subject: mm, vmscan: show the number of skipped pages in mm_vmscan_lru_isolate X-Git-Tag: v4.14-rc1~1445^2~50 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=1265e3a69f1ea97357536773d48c92a409e01eaf;p=platform%2Fkernel%2Flinux-rpi3.git 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. Link: http://lkml.kernel.org/r/20170104101942.4860-4-mhocko@kernel.org Signed-off-by: Michal Hocko Acked-by: Minchan Kim Acked-by: Mel Gorman Acked-by: Vlastimil Babka Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/include/trace/events/vmscan.h b/include/trace/events/vmscan.h index c295d8f..340b3c4 100644 --- a/include/trace/events/vmscan.h +++ b/include/trace/events/vmscan.h @@ -274,17 +274,19 @@ TRACE_EVENT(mm_vmscan_lru_isolate, int order, unsigned long nr_requested, unsigned long nr_scanned, + unsigned long nr_skipped, unsigned long nr_taken, isolate_mode_t isolate_mode, int file), - TP_ARGS(classzone_idx, order, nr_requested, nr_scanned, nr_taken, isolate_mode, file), + TP_ARGS(classzone_idx, order, nr_requested, nr_scanned, nr_skipped, nr_taken, isolate_mode, file), TP_STRUCT__entry( __field(int, classzone_idx) __field(int, order) __field(unsigned long, nr_requested) __field(unsigned long, nr_scanned) + __field(unsigned long, nr_skipped) __field(unsigned long, nr_taken) __field(isolate_mode_t, isolate_mode) __field(int, file) @@ -295,17 +297,19 @@ TRACE_EVENT(mm_vmscan_lru_isolate, __entry->order = order; __entry->nr_requested = nr_requested; __entry->nr_scanned = nr_scanned; + __entry->nr_skipped = nr_skipped; __entry->nr_taken = nr_taken; __entry->isolate_mode = isolate_mode; __entry->file = file; ), - TP_printk("isolate_mode=%d classzone=%d order=%d nr_requested=%lu nr_scanned=%lu nr_taken=%lu file=%d", + TP_printk("isolate_mode=%d classzone=%d order=%d nr_requested=%lu nr_scanned=%lu nr_skipped=%lu nr_taken=%lu file=%d", __entry->isolate_mode, __entry->classzone_idx, __entry->order, __entry->nr_requested, __entry->nr_scanned, + __entry->nr_skipped, __entry->nr_taken, __entry->file) ); diff --git a/mm/vmscan.c b/mm/vmscan.c index a34bf51..d2fc97c 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -1437,6 +1437,7 @@ 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); @@ -1488,14 +1489,13 @@ 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]; } /* @@ -1503,13 +1503,14 @@ 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; }