From: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
To: Ingo Molnar <mingo@kernel.org>, Peter Zijlstra <peterz@infradead.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
Mel Gorman <mgorman@techsingularity.net>,
Rik van Riel <riel@surriel.com>,
Srikar Dronamraju <srikar@linux.vnet.ibm.com>,
Thomas Gleixner <tglx@linutronix.de>
Subject: [PATCH v2 11/19] sched/numa: Restrict migrating in parallel to the same node.
Date: Wed, 20 Jun 2018 22:32:52 +0530 [thread overview]
Message-ID: <1529514181-9842-12-git-send-email-srikar@linux.vnet.ibm.com> (raw)
In-Reply-To: <1529514181-9842-1-git-send-email-srikar@linux.vnet.ibm.com>
Since task migration under numa balancing can happen in parallel, more
than one task might choose to move to the same node at the same time.
This can cause load imbalances at the node level.
The problem is more likely if there are more cores per node or more
nodes in system.
Use a per-node variable to indicate if task migration
to the node under numa balance is currently active.
This per-node variable will not track swapping of tasks.
Running SPECjbb2005 on a 4 node machine and comparing bops/JVM
JVMS LAST_PATCH WITH_PATCH %CHANGE
16 25436.1 25657.9 0.87
1 74031 74435 0.54
Running SPECjbb2005 on a 16 node machine and comparing bops/JVM
JVMS LAST_PATCH WITH_PATCH %CHANGE
8 110355 101748 -7.79
1 178401 170818 -4.25
(numbers from v1 based on v4.17-rc5)
Testcase Time: Min Max Avg StdDev
numa01.sh Real: 414.64 819.20 556.08 147.70
numa01.sh Sys: 77.52 205.04 139.40 52.05
numa01.sh User: 37043.24 61757.88 45517.48 9290.38
numa02.sh Real: 60.80 63.32 61.63 0.88
numa02.sh Sys: 17.35 39.37 25.71 7.33
numa02.sh User: 5213.79 5374.73 5268.90 55.09
numa03.sh Real: 780.09 948.64 831.43 63.02
numa03.sh Sys: 104.96 136.92 116.31 11.34
numa03.sh User: 60465.42 73339.78 64368.03 4700.14
numa04.sh Real: 412.60 681.92 521.29 96.64
numa04.sh Sys: 210.32 314.10 251.77 37.71
numa04.sh User: 34026.38 45581.20 38534.49 4198.53
numa05.sh Real: 394.79 439.63 411.35 16.87
numa05.sh Sys: 238.32 330.09 292.31 38.32
numa05.sh User: 33456.45 34876.07 34138.62 609.45
Testcase Time: Min Max Avg StdDev %Change
numa01.sh Real: 434.84 676.90 550.53 106.24 1.008%
numa01.sh Sys: 125.98 217.34 179.41 30.35 -22.3%
numa01.sh User: 38318.48 53789.56 45864.17 6620.80 -0.75%
numa02.sh Real: 60.06 61.27 60.59 0.45 1.716%
numa02.sh Sys: 14.25 17.86 16.09 1.28 59.78%
numa02.sh User: 5190.13 5225.67 5209.24 13.19 1.145%
numa03.sh Real: 748.21 960.25 823.15 73.51 1.005%
numa03.sh Sys: 96.68 122.10 110.42 11.29 5.334%
numa03.sh User: 58222.16 72595.27 63552.22 5048.87 1.283%
numa04.sh Real: 433.08 630.55 499.30 68.15 4.404%
numa04.sh Sys: 245.22 386.75 306.09 63.32 -17.7%
numa04.sh User: 35014.68 46151.72 38530.26 3924.65 0.010%
numa05.sh Real: 394.77 410.07 401.41 5.99 2.476%
numa05.sh Sys: 212.40 301.82 256.23 35.41 14.08%
numa05.sh User: 33224.86 34201.40 33665.61 313.40 1.405%
Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
---
include/linux/mmzone.h | 1 +
kernel/sched/fair.c | 14 ++++++++++++++
mm/page_alloc.c | 1 +
3 files changed, 16 insertions(+)
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 32699b2..b0767703 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -677,6 +677,7 @@ struct zonelist {
/* Number of pages migrated during the rate limiting time interval */
unsigned long numabalancing_migrate_nr_pages;
+ int active_node_migrate;
#endif
/*
* This is a per-node reserve of pages that are not available
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 50c7727..87fb20e 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -1478,11 +1478,22 @@ struct task_numa_env {
static void task_numa_assign(struct task_numa_env *env,
struct task_struct *p, long imp)
{
+ pg_data_t *pgdat = NODE_DATA(cpu_to_node(env->dst_cpu));
struct rq *rq = cpu_rq(env->dst_cpu);
if (xchg(&rq->numa_migrate_on, 1))
return;
+ if (!env->best_task && env->best_cpu != -1)
+ WRITE_ONCE(pgdat->active_node_migrate, 0);
+
+ if (!p) {
+ if (xchg(&pgdat->active_node_migrate, 1)) {
+ WRITE_ONCE(rq->numa_migrate_on, 0);
+ return;
+ }
+ }
+
if (env->best_cpu != -1) {
rq = cpu_rq(env->best_cpu);
WRITE_ONCE(rq->numa_migrate_on, 0);
@@ -1818,8 +1829,11 @@ static int task_numa_migrate(struct task_struct *p)
best_rq = cpu_rq(env.best_cpu);
if (env.best_task == NULL) {
+ pg_data_t *pgdat = NODE_DATA(cpu_to_node(env.dst_cpu));
+
ret = migrate_task_to(p, env.best_cpu);
WRITE_ONCE(best_rq->numa_migrate_on, 0);
+ WRITE_ONCE(pgdat->active_node_migrate, 0);
if (ret != 0)
trace_sched_stick_numa(p, env.src_cpu, env.best_cpu);
return ret;
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 22320ea27..8a522d2 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -6209,6 +6209,7 @@ static void __paginginit free_area_init_core(struct pglist_data *pgdat)
#ifdef CONFIG_NUMA_BALANCING
spin_lock_init(&pgdat->numabalancing_migrate_lock);
pgdat->numabalancing_migrate_nr_pages = 0;
+ pgdat->active_node_migrate = 0;
pgdat->numabalancing_migrate_next_window = jiffies;
#endif
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
--
1.8.3.1
next prev parent reply other threads:[~2018-06-20 17:03 UTC|newest]
Thread overview: 53+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-06-20 17:02 [PATCH v2 00/19] Fixes for sched/numa_balancing Srikar Dronamraju
2018-06-20 17:02 ` [PATCH v2 01/19] sched/numa: Remove redundant field Srikar Dronamraju
2018-07-25 14:23 ` [tip:sched/core] " tip-bot for Srikar Dronamraju
2018-06-20 17:02 ` [PATCH v2 02/19] sched/numa: Evaluate move once per node Srikar Dronamraju
2018-06-21 9:06 ` Mel Gorman
2018-07-25 14:24 ` [tip:sched/core] " tip-bot for Srikar Dronamraju
2018-06-20 17:02 ` [PATCH v2 03/19] sched/numa: Simplify load_too_imbalanced Srikar Dronamraju
2018-07-25 14:24 ` [tip:sched/core] sched/numa: Simplify load_too_imbalanced() tip-bot for Srikar Dronamraju
2018-06-20 17:02 ` [PATCH v2 04/19] sched/numa: Set preferred_node based on best_cpu Srikar Dronamraju
2018-06-21 9:17 ` Mel Gorman
2018-07-25 14:25 ` [tip:sched/core] " tip-bot for Srikar Dronamraju
2018-06-20 17:02 ` [PATCH v2 05/19] sched/numa: Use task faults only if numa_group is not yet setup Srikar Dronamraju
2018-06-21 9:38 ` Mel Gorman
2018-07-25 14:25 ` [tip:sched/core] sched/numa: Use task faults only if numa_group is not yet set up tip-bot for Srikar Dronamraju
2018-06-20 17:02 ` [PATCH v2 06/19] sched/debug: Reverse the order of printing faults Srikar Dronamraju
2018-07-25 14:26 ` [tip:sched/core] " tip-bot for Srikar Dronamraju
2018-06-20 17:02 ` [PATCH v2 07/19] sched/numa: Skip nodes that are at hoplimit Srikar Dronamraju
2018-07-25 14:27 ` [tip:sched/core] sched/numa: Skip nodes that are at 'hoplimit' tip-bot for Srikar Dronamraju
2018-06-20 17:02 ` [PATCH v2 08/19] sched/numa: Remove unused task_capacity from numa_stats Srikar Dronamraju
2018-07-25 14:27 ` [tip:sched/core] sched/numa: Remove unused task_capacity from 'struct numa_stats' tip-bot for Srikar Dronamraju
2018-06-20 17:02 ` [PATCH v2 09/19] sched/numa: Modify migrate_swap to accept additional params Srikar Dronamraju
2018-07-25 14:28 ` [tip:sched/core] sched/numa: Modify migrate_swap() to accept additional parameters tip-bot for Srikar Dronamraju
2018-06-20 17:02 ` [PATCH v2 10/19] sched/numa: Stop multiple tasks from moving to the cpu at the same time Srikar Dronamraju
2018-06-20 17:02 ` Srikar Dronamraju [this message]
2018-07-23 10:38 ` [PATCH v2 11/19] sched/numa: Restrict migrating in parallel to the same node Peter Zijlstra
2018-07-23 11:16 ` Srikar Dronamraju
2018-06-20 17:02 ` [PATCH v2 12/19] sched/numa: Remove numa_has_capacity Srikar Dronamraju
2018-07-25 14:28 ` [tip:sched/core] sched/numa: Remove numa_has_capacity() tip-bot for Srikar Dronamraju
2018-06-20 17:02 ` [PATCH v2 13/19] mm/migrate: Use xchg instead of spinlock Srikar Dronamraju
2018-06-21 9:51 ` Mel Gorman
2018-07-23 10:54 ` Peter Zijlstra
2018-07-23 11:20 ` Srikar Dronamraju
2018-07-23 14:04 ` Peter Zijlstra
2018-06-20 17:02 ` [PATCH v2 14/19] sched/numa: Updation of scan period need not be in lock Srikar Dronamraju
2018-06-21 9:51 ` Mel Gorman
2018-07-25 14:29 ` [tip:sched/core] sched/numa: Update the scan period without holding the numa_group lock tip-bot for Srikar Dronamraju
2018-06-20 17:02 ` [PATCH v2 15/19] sched/numa: Use group_weights to identify if migration degrades locality Srikar Dronamraju
2018-07-25 14:29 ` [tip:sched/core] " tip-bot for Srikar Dronamraju
2018-06-20 17:02 ` [PATCH v2 16/19] sched/numa: Detect if node actively handling migration Srikar Dronamraju
2018-06-20 17:02 ` [PATCH v2 17/19] sched/numa: Pass destination cpu as a parameter to migrate_task_rq Srikar Dronamraju
2018-06-20 17:02 ` [PATCH v2 18/19] sched/numa: Reset scan rate whenever task moves across nodes Srikar Dronamraju
2018-06-21 10:05 ` Mel Gorman
2018-07-04 11:19 ` Srikar Dronamraju
2018-06-20 17:03 ` [PATCH v2 19/19] sched/numa: Move task_placement closer to numa_migrate_preferred Srikar Dronamraju
2018-06-21 10:06 ` Mel Gorman
2018-07-25 14:30 ` [tip:sched/core] sched/numa: Move task_numa_placement() closer to numa_migrate_preferred() tip-bot for Srikar Dronamraju
2018-06-20 17:03 ` [PATCH v2 00/19] Fixes for sched/numa_balancing Srikar Dronamraju
2018-07-23 13:57 ` Peter Zijlstra
2018-07-23 15:09 ` Srikar Dronamraju
2018-07-23 15:21 ` Peter Zijlstra
2018-07-23 16:29 ` Srikar Dronamraju
2018-07-23 16:47 ` Peter Zijlstra
2018-07-23 15:33 ` Rik van Riel
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