The patch titled
vmscan: take order into consideration when deciding if kswapd is in trouble
has been added to the -mm tree. Its filename is
vmscan-take-order-into-consideration-when-deciding-if-kswapd-is-in-trouble.patch
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://userweb.kernel.org/~akpm/stuff/added-to-mm.txt to find
out what to do about this
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: vmscan: take order into consideration when deciding if kswapd is in trouble
From: Mel Gorman <mel@xxxxxxxxx>
If reclaim fails to make sufficient progress, the priority is raised.
Once the priority is higher, kswapd starts waiting on congestion.
However, on systems with large numbers of high-order atomics due to crappy
network cards, it's important that kswapd keep working in parallel to save
their sorry ass.
This patch takes into account the order kswapd is reclaiming at before
waiting on congestion. The higher the order, the longer it is before
kswapd considers itself to be in trouble. The impact is that kswapd works
harder in parallel rather than depending on direct reclaimers or atomic
allocations to fail.
Signed-off-by: Mel Gorman <mel@xxxxxxxxx>
Cc: Frans Pop <elendil@xxxxxxxxx>
Cc: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxx>
Cc: Christoph Lameter <cl@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/vmscan.c | 14 ++++++++++++--
1 file changed, 12 insertions(+), 2 deletions(-)
diff -puN mm/vmscan.c~vmscan-take-order-into-consideration-when-deciding-if-kswapd-is-in-trouble mm/vmscan.c
--- a/mm/vmscan.c~vmscan-take-order-into-consideration-when-deciding-if-kswapd-is-in-trouble
+++ a/mm/vmscan.c
@@ -1950,7 +1950,7 @@ static int sleeping_prematurely(int orde
static unsigned long balance_pgdat(pg_data_t *pgdat, int order)
{
int all_zones_ok;
- int priority;
+ int priority, congestion_priority;
int i;
unsigned long total_scanned;
struct reclaim_state *reclaim_state = current->reclaim_state;
@@ -1971,6 +1971,16 @@ static unsigned long balance_pgdat(pg_da
*/
int temp_priority[MAX_NR_ZONES];
+ /*
+ * When priority reaches congestion_priority, kswapd will sleep
+ * for a short time while congestion clears. The higher the
+ * order being reclaimed, the less likely kswapd will go to
+ * sleep as high-order allocations are harder to reclaim and
+ * stall direct reclaimers longer
+ */
+ congestion_priority = DEF_PRIORITY - 2;
+ congestion_priority -= min(congestion_priority, sc.order);
+
loop_again:
total_scanned = 0;
sc.nr_reclaimed = 0;
@@ -2096,7 +2106,7 @@ loop_again:
* OK, kswapd is getting into trouble. Take a nap, then take
* another pass across the zones.
*/
- if (total_scanned && priority < DEF_PRIORITY - 2)
+ if (total_scanned && priority < congestion_priority)
congestion_wait(BLK_RW_ASYNC, HZ/10);
/*
_
Patches currently in -mm which might be from mel@xxxxxxxxx are
page-allocator-always-wake-kswapd-when-restarting-an-allocation-attempt-after-direct-reclaim-failed.patch
page-allocator-do-not-allow-interrupts-to-use-alloc_harder.patch
linux-next.patch
mm-add-notifier-in-pageblock-isolation-for-balloon-drivers.patch
powerpc-make-the-cmm-memory-hotplug-aware.patch
mm-warn-once-when-a-page-is-freed-with-pg_mlocked-set.patch
nodemask-make-nodemask_alloc-more-general.patch
hugetlb-rework-hstate_next_node_-functions.patch
hugetlb-add-nodemask-arg-to-huge-page-alloc-free-and-surplus-adjust-functions.patch
hugetlb-add-nodemask-arg-to-huge-page-alloc-free-and-surplus-adjust-functions-fix.patch
hugetlb-factor-init_nodemask_of_node.patch
hugetlb-derive-huge-pages-nodes-allowed-from-task-mempolicy.patch
hugetlb-add-generic-definition-of-numa_no_node.patch
hugetlb-add-per-node-hstate-attributes.patch
hugetlb-update-hugetlb-documentation-for-numa-controls.patch
hugetlb-use-only-nodes-with-memory-for-huge-pages.patch
mm-clear-node-in-n_high_memory-and-stop-kswapd-when-all-memory-is-offlined.patch
hugetlb-handle-memory-hot-plug-events.patch
hugetlb-offload-per-node-attribute-registrations.patch
mm-add-gfp-flags-for-nodemask_alloc-slab-allocations.patch
page-allocator-wait-on-both-sync-and-async-congestion-after-direct-reclaim.patch
vmscan-have-kswapd-sleep-for-a-short-interval-and-double-check-it-should-be-asleep.patch
vmscan-take-order-into-consideration-when-deciding-if-kswapd-is-in-trouble.patch
add-debugging-aid-for-memory-initialisation-problems.patch
--
To unsubscribe from this list: send the line "unsubscribe mm-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
