The patch titled
Subject: mm: vmstat: account per-zone stalls and pages skipped during reclaim
has been added to the -mm tree. Its filename is
mm-vmstat-account-per-zone-stalls-and-pages-skipped-during-reclaim.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-vmstat-account-per-zone-stalls-and-pages-skipped-during-reclaim.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-vmstat-account-per-zone-stalls-and-pages-skipped-during-reclaim.patch
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------------------------------------------------------
From: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Subject: mm: vmstat: account per-zone stalls and pages skipped during reclaim
The vmstat allocstall was fairly useful in the general sense but
node-based LRUs change that. It's important to know if a stall was for an
address-limited allocation request as this will require skipping pages
from other zones. This patch adds pgstall_* counters to replace
allocstall. The sum of the counters will equal the old allocstall so it
can be trivially recalculated. A high number of address-limited
allocation requests may result in a lot of useless LRU scanning for
suitable pages.
As address-limited allocations require pages to be skipped, it's important
to know how much useless LRU scanning took place so this patch adds
pgskip* counters. This yields the following model
1. The number of address-space limited stalls can be accounted for (pgstall)
2. The amount of useless work required to reclaim the data is accounted (pgskip)
3. The total number of scans is available from pgscan_kswapd and pgscan_direct
so from that the ratio of useful to useless scans can be calculated.
Link: http://lkml.kernel.org/r/1466518566-30034-28-git-send-email-mgorman@xxxxxxxxxxxxxxxxxxx
Signed-off-by: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Acked-by: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/vm_event_item.h | 4 +++-
mm/vmscan.c | 15 +++++++++++++--
mm/vmstat.c | 3 ++-
3 files changed, 18 insertions(+), 4 deletions(-)
diff -puN include/linux/vm_event_item.h~mm-vmstat-account-per-zone-stalls-and-pages-skipped-during-reclaim include/linux/vm_event_item.h
--- a/include/linux/vm_event_item.h~mm-vmstat-account-per-zone-stalls-and-pages-skipped-during-reclaim
+++ a/include/linux/vm_event_item.h
@@ -23,6 +23,8 @@
enum vm_event_item { PGPGIN, PGPGOUT, PSWPIN, PSWPOUT,
FOR_ALL_ZONES(PGALLOC),
+ FOR_ALL_ZONES(PGSTALL),
+ FOR_ALL_ZONES(PGSCAN_SKIP),
PGFREE, PGACTIVATE, PGDEACTIVATE,
PGFAULT, PGMAJFAULT,
PGLAZYFREED,
@@ -37,7 +39,7 @@ enum vm_event_item { PGPGIN, PGPGOUT, PS
#endif
PGINODESTEAL, SLABS_SCANNED, KSWAPD_INODESTEAL,
KSWAPD_LOW_WMARK_HIT_QUICKLY, KSWAPD_HIGH_WMARK_HIT_QUICKLY,
- PAGEOUTRUN, ALLOCSTALL, PGROTATED,
+ PAGEOUTRUN, PGROTATED,
DROP_PAGECACHE, DROP_SLAB,
#ifdef CONFIG_NUMA_BALANCING
NUMA_PTE_UPDATES,
diff -puN mm/vmscan.c~mm-vmstat-account-per-zone-stalls-and-pages-skipped-during-reclaim mm/vmscan.c
--- a/mm/vmscan.c~mm-vmstat-account-per-zone-stalls-and-pages-skipped-during-reclaim
+++ a/mm/vmscan.c
@@ -1394,6 +1394,7 @@ static unsigned long isolate_lru_pages(u
struct list_head *src = &lruvec->lists[lru];
unsigned long nr_taken = 0;
unsigned long nr_zone_taken[MAX_NR_ZONES] = { 0 };
+ unsigned long nr_skipped[MAX_NR_ZONES] = { 0, };
unsigned long scan, nr_pages;
LIST_HEAD(pages_skipped);
@@ -1408,6 +1409,7 @@ static unsigned long isolate_lru_pages(u
if (page_zonenum(page) > sc->reclaim_idx) {
list_move(&page->lru, &pages_skipped);
+ nr_skipped[page_zonenum(page)]++;
continue;
}
@@ -1436,8 +1438,17 @@ static unsigned long isolate_lru_pages(u
* scanning would soon rescan the same pages to skip and put the
* system at risk of premature OOM.
*/
- if (!list_empty(&pages_skipped))
+ if (!list_empty(&pages_skipped)) {
+ int zid;
+
list_splice(&pages_skipped, src);
+ for (zid = 0; zid < MAX_NR_ZONES; zid++) {
+ if (!nr_skipped[zid])
+ continue;
+
+ __count_zid_vm_events(PGSCAN_SKIP, zid, nr_skipped[zid]);
+ }
+ }
*nr_scanned = scan;
trace_mm_vmscan_lru_isolate(sc->reclaim_idx, sc->order, nr_to_scan, scan,
nr_taken, mode, is_file_lru(lru));
@@ -2690,7 +2701,7 @@ retry:
delayacct_freepages_start();
if (global_reclaim(sc))
- count_vm_event(ALLOCSTALL);
+ __count_zid_vm_events(PGSTALL, classzone_idx, 1);
do {
vmpressure_prio(sc->gfp_mask, sc->target_mem_cgroup,
diff -puN mm/vmstat.c~mm-vmstat-account-per-zone-stalls-and-pages-skipped-during-reclaim mm/vmstat.c
--- a/mm/vmstat.c~mm-vmstat-account-per-zone-stalls-and-pages-skipped-during-reclaim
+++ a/mm/vmstat.c
@@ -969,6 +969,8 @@ const char * const vmstat_text[] = {
"pswpout",
TEXTS_FOR_ZONES("pgalloc")
+ TEXTS_FOR_ZONES("pgstall")
+ TEXTS_FOR_ZONES("pgskip")
"pgfree",
"pgactivate",
@@ -994,7 +996,6 @@ const char * const vmstat_text[] = {
"kswapd_low_wmark_hit_quickly",
"kswapd_high_wmark_hit_quickly",
"pageoutrun",
- "allocstall",
"pgrotated",
_
Patches currently in -mm which might be from mgorman@xxxxxxxxxxxxxxxxxxx are
mm-slaub-add-__gfp_atomic-to-the-gfp-reclaim-mask.patch
mm-vmstat-add-infrastructure-for-per-node-vmstats.patch
mm-vmscan-move-lru_lock-to-the-node.patch
mm-vmscan-move-lru-lists-to-node.patch
mm-vmscan-begin-reclaiming-pages-on-a-per-node-basis.patch
mm-vmscan-have-kswapd-only-scan-based-on-the-highest-requested-zone.patch
mm-vmscan-make-kswapd-reclaim-in-terms-of-nodes.patch
mm-vmscan-remove-balance-gap.patch
mm-vmscan-simplify-the-logic-deciding-whether-kswapd-sleeps.patch
mm-vmscan-by-default-have-direct-reclaim-only-shrink-once-per-node.patch
mm-vmscan-remove-duplicate-logic-clearing-node-congestion-and-dirty-state.patch
mm-vmscan-do-not-reclaim-from-kswapd-if-there-is-any-eligible-zone.patch
mm-vmscan-make-shrink_node-decisions-more-node-centric.patch
mm-memcg-move-memcg-limit-enforcement-from-zones-to-nodes.patch
mm-workingset-make-working-set-detection-node-aware.patch
mm-page_alloc-consider-dirtyable-memory-in-terms-of-nodes.patch
mm-move-page-mapped-accounting-to-the-node.patch
mm-rename-nr_anon_pages-to-nr_anon_mapped.patch
mm-move-most-file-based-accounting-to-the-node.patch
mm-move-vmscan-writes-and-file-write-accounting-to-the-node.patch
mm-vmscan-update-classzone_idx-if-buffer_heads_over_limit.patch
mm-vmscan-only-wakeup-kswapd-once-per-node-for-the-requested-classzone.patch
mm-convert-zone_reclaim-to-node_reclaim.patch
mm-vmscan-add-classzone-information-to-tracepoints.patch
mm-page_alloc-remove-fair-zone-allocation-policy.patch
mm-page_alloc-cache-the-last-node-whose-dirty-limit-is-reached.patch
mm-vmstat-replace-__count_zone_vm_events-with-a-zone-id-equivalent.patch
mm-vmstat-account-per-zone-stalls-and-pages-skipped-during-reclaim.patch
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