From: Mel Gorman <mgorman@techsingularity.net>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>,
Vincent Guittot <vincent.guittot@linaro.org>,
Juri Lelli <juri.lelli@redhat.com>,
Dietmar Eggemann <dietmar.eggemann@arm.com>,
Steven Rostedt <rostedt@goodmis.org>,
Ben Segall <bsegall@google.com>,
Valentin Schneider <valentin.schneider@arm.com>,
Phil Auld <pauld@redhat.com>, Hillf Danton <hdanton@sina.com>,
LKML <linux-kernel@vger.kernel.org>,
Mel Gorman <mgorman@techsingularity.net>
Subject: [PATCH 11/13] sched/numa: Find an alternative idle CPU if the CPU is part of an active NUMA balance
Date: Mon, 24 Feb 2020 09:52:21 +0000 [thread overview]
Message-ID: <20200224095223.13361-12-mgorman@techsingularity.net> (raw)
In-Reply-To: <20200224095223.13361-1-mgorman@techsingularity.net>
Multiple tasks can attempt to select and idle CPU but fail because
numa_migrate_on is already set and the migration fails. Instead of failing,
scan for an alternative idle CPU. select_idle_sibling is not used because
it requires IRQs to be disabled and it ignores numa_migrate_on allowing
multiple tasks to stack. This scan may still fail if there are idle
candidate CPUs due to races but if this occurs, it's best that a task
stay on an available CPU that move to a contended one.
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
---
kernel/sched/fair.c | 40 ++++++++++++++++++++++------------------
1 file changed, 22 insertions(+), 18 deletions(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index e285aa0cdd4f..ee14cd9815ec 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -1624,15 +1624,34 @@ static void task_numa_assign(struct task_numa_env *env,
{
struct rq *rq = cpu_rq(env->dst_cpu);
- /* Bail out if run-queue part of active NUMA balance. */
- if (env->best_cpu != env->dst_cpu && xchg(&rq->numa_migrate_on, 1))
+ /* Check if run-queue part of active NUMA balance. */
+ if (env->best_cpu != env->dst_cpu && xchg(&rq->numa_migrate_on, 1)) {
+ int cpu;
+ int start = env->dst_cpu;
+
+ /* Find alternative idle CPU. */
+ for_each_cpu_wrap(cpu, cpumask_of_node(env->dst_nid), start) {
+ if (cpu == env->best_cpu || !idle_cpu(cpu) ||
+ !cpumask_test_cpu(cpu, env->p->cpus_ptr)) {
+ continue;
+ }
+
+ env->dst_cpu = cpu;
+ rq = cpu_rq(env->dst_cpu);
+ if (!xchg(&rq->numa_migrate_on, 1))
+ goto assign;
+ }
+
+ /* Failed to find an alternative idle CPU */
return;
+ }
+assign:
/*
* Clear previous best_cpu/rq numa-migrate flag, since task now
* found a better CPU to move/swap.
*/
- if (env->best_cpu != -1) {
+ if (env->best_cpu != -1 && env->best_cpu != env->dst_cpu) {
rq = cpu_rq(env->best_cpu);
WRITE_ONCE(rq->numa_migrate_on, 0);
}
@@ -1806,21 +1825,6 @@ static void task_numa_compare(struct task_numa_env *env,
cpu = env->best_cpu;
}
- /*
- * Use select_idle_sibling if the previously found idle CPU is
- * not idle any more.
- */
- if (!idle_cpu(cpu)) {
- /*
- * select_idle_siblings() uses an per-CPU cpumask that
- * can be used from IRQ context.
- */
- local_irq_disable();
- cpu = select_idle_sibling(env->p, env->src_cpu,
- env->dst_cpu);
- local_irq_enable();
- }
-
env->dst_cpu = cpu;
}
--
2.16.4
next prev parent reply other threads:[~2020-02-24 9:54 UTC|newest]
Thread overview: 86+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-24 9:52 [PATCH 00/13] Reconcile NUMA balancing decisions with the load balancer v6 Mel Gorman
2020-02-24 9:52 ` [PATCH 01/13] sched/fair: Allow a per-CPU kthread waking a task to stack on the same CPU, to fix XFS performance regression Mel Gorman
2020-02-24 9:52 ` [PATCH 02/13] sched/numa: Trace when no candidate CPU was found on the preferred node Mel Gorman
2020-02-24 15:20 ` [tip: sched/core] " tip-bot2 for Mel Gorman
2020-02-24 9:52 ` [PATCH 03/13] sched/numa: Distinguish between the different task_numa_migrate failure cases Mel Gorman
2020-02-24 15:20 ` [tip: sched/core] sched/numa: Distinguish between the different task_numa_migrate() " tip-bot2 for Mel Gorman
2020-02-24 9:52 ` [PATCH 04/13] sched/fair: Reorder enqueue/dequeue_task_fair path Mel Gorman
2020-02-24 15:20 ` [tip: sched/core] " tip-bot2 for Vincent Guittot
2020-02-24 9:52 ` [PATCH 05/13] sched/numa: Replace runnable_load_avg by load_avg Mel Gorman
2020-02-24 15:20 ` [tip: sched/core] " tip-bot2 for Vincent Guittot
2020-02-24 9:52 ` [PATCH 06/13] sched/numa: Use similar logic to the load balancer for moving between domains with spare capacity Mel Gorman
2020-02-24 15:20 ` [tip: sched/core] " tip-bot2 for Mel Gorman
2020-02-24 9:52 ` [PATCH 07/13] sched/pelt: Remove unused runnable load average Mel Gorman
2020-02-24 15:20 ` [tip: sched/core] " tip-bot2 for Vincent Guittot
2020-02-24 9:52 ` [PATCH 08/13] sched/pelt: Add a new runnable average signal Mel Gorman
2020-02-24 15:20 ` [tip: sched/core] " tip-bot2 for Vincent Guittot
2020-02-24 16:01 ` Valentin Schneider
2020-02-24 16:34 ` Mel Gorman
2020-02-25 8:23 ` Vincent Guittot
2020-02-24 9:52 ` [PATCH 09/13] sched/fair: Take into account runnable_avg to classify group Mel Gorman
2020-02-24 15:20 ` [tip: sched/core] " tip-bot2 for Vincent Guittot
2020-02-24 9:52 ` [PATCH 10/13] sched/numa: Prefer using an idle cpu as a migration target instead of comparing tasks Mel Gorman
2020-02-24 15:20 ` [tip: sched/core] sched/numa: Prefer using an idle CPU " tip-bot2 for Mel Gorman
2020-02-24 9:52 ` Mel Gorman [this message]
2020-02-24 15:20 ` [tip: sched/core] sched/numa: Find an alternative idle CPU if the CPU is part of an active NUMA balance tip-bot2 for Mel Gorman
2020-02-24 9:52 ` [PATCH 12/13] sched/numa: Bias swapping tasks based on their preferred node Mel Gorman
2020-02-24 15:20 ` [tip: sched/core] " tip-bot2 for Mel Gorman
2020-02-24 9:52 ` [PATCH 13/13] sched/numa: Stop an exhastive search if a reasonable swap candidate or idle CPU is found Mel Gorman
2020-02-24 15:20 ` [tip: sched/core] " tip-bot2 for Mel Gorman
2020-02-24 15:16 ` [PATCH 00/13] Reconcile NUMA balancing decisions with the load balancer v6 Ingo Molnar
2020-02-25 11:59 ` Mel Gorman
2020-02-25 13:28 ` Vincent Guittot
2020-02-25 14:24 ` Mel Gorman
2020-02-25 14:53 ` Vincent Guittot
2020-02-27 9:09 ` Ingo Molnar
2020-03-09 19:12 ` Phil Auld
2020-03-09 20:36 ` Mel Gorman
2020-03-12 9:54 ` Mel Gorman
2020-03-12 12:17 ` Jirka Hladky
[not found] ` <CAE4VaGA4q4_qfC5qe3zaLRfiJhvMaSb2WADgOcQeTwmPvNat+A@mail.gmail.com>
2020-03-12 15:56 ` Mel Gorman
2020-03-12 17:06 ` Jirka Hladky
[not found] ` <CAE4VaGD8DUEi6JnKd8vrqUL_8HZXnNyHMoK2D+1-F5wo+5Z53Q@mail.gmail.com>
2020-03-12 21:47 ` Mel Gorman
2020-03-12 22:24 ` Jirka Hladky
2020-03-20 15:08 ` Jirka Hladky
[not found] ` <CAE4VaGC09OfU2zXeq2yp_N0zXMbTku5ETz0KEocGi-RSiKXv-w@mail.gmail.com>
2020-03-20 15:22 ` Mel Gorman
2020-03-20 15:33 ` Jirka Hladky
[not found] ` <CAE4VaGBGbTT8dqNyLWAwuiqL8E+3p1_SqP6XTTV71wNZMjc9Zg@mail.gmail.com>
2020-03-20 16:38 ` Mel Gorman
2020-03-20 17:21 ` Jirka Hladky
2020-05-07 15:24 ` Jirka Hladky
2020-05-07 15:54 ` Mel Gorman
2020-05-07 16:29 ` Jirka Hladky
2020-05-07 17:49 ` Phil Auld
[not found] ` <20200508034741.13036-1-hdanton@sina.com>
2020-05-18 14:52 ` Jirka Hladky
[not found] ` <20200519043154.10876-1-hdanton@sina.com>
2020-05-20 13:58 ` Jirka Hladky
2020-05-20 16:01 ` Jirka Hladky
2020-05-21 11:06 ` Mel Gorman
[not found] ` <20200521140931.15232-1-hdanton@sina.com>
2020-05-21 16:04 ` Mel Gorman
[not found] ` <20200522010950.3336-1-hdanton@sina.com>
2020-05-22 11:05 ` Mel Gorman
2020-05-08 9:22 ` Mel Gorman
2020-05-08 11:05 ` Jirka Hladky
[not found] ` <CAE4VaGC_v6On-YvqdTwAWu3Mq4ofiV0pLov-QpV+QHr_SJr+Rw@mail.gmail.com>
2020-05-13 14:57 ` Jirka Hladky
2020-05-13 15:30 ` Mel Gorman
2020-05-13 16:20 ` Jirka Hladky
2020-05-14 9:50 ` Mel Gorman
[not found] ` <CAE4VaGCGUFOAZ+YHDnmeJ95o4W0j04Yb7EWnf8a43caUQs_WuQ@mail.gmail.com>
2020-05-14 10:08 ` Mel Gorman
2020-05-14 10:22 ` Jirka Hladky
2020-05-14 11:50 ` Mel Gorman
2020-05-14 13:34 ` Jirka Hladky
2020-05-14 15:31 ` Peter Zijlstra
2020-05-15 8:47 ` Mel Gorman
2020-05-15 11:17 ` Peter Zijlstra
2020-05-15 13:03 ` Mel Gorman
2020-05-15 13:12 ` Peter Zijlstra
2020-05-15 13:28 ` Peter Zijlstra
2020-05-15 14:24 ` Peter Zijlstra
2020-05-21 10:38 ` Mel Gorman
2020-05-21 11:41 ` Peter Zijlstra
2020-05-22 13:28 ` Mel Gorman
2020-05-22 14:38 ` Peter Zijlstra
2020-05-15 11:28 ` Peter Zijlstra
2020-05-15 12:22 ` Mel Gorman
2020-05-15 12:51 ` Peter Zijlstra
2020-05-15 14:43 ` Jirka Hladky
-- strict thread matches above, loose matches on Subject: below --
2020-02-19 14:07 [PATCH 00/13] Reconcile NUMA balancing decisions with the load balancer v5 Mel Gorman
2020-02-19 14:07 ` [PATCH 11/13] sched/numa: Find an alternative idle CPU if the CPU is part of an active NUMA balance Mel Gorman
2020-02-19 13:54 [PATCH 00/13] Reconcile NUMA balancing decisions with the load balancer v4 Mel Gorman
2020-02-19 13:54 ` [PATCH 11/13] sched/numa: Find an alternative idle CPU if the CPU is part of an active NUMA balance Mel Gorman
2020-02-17 10:43 [PATCH 00/13] Reconcile NUMA balancing decisions with the load balancer v3 Mel Gorman
2020-02-17 10:44 ` [PATCH 11/13] sched/numa: Find an alternative idle CPU if the CPU is part of an active NUMA balance Mel Gorman
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20200224095223.13361-12-mgorman@techsingularity.net \
--to=mgorman@techsingularity.net \
--cc=bsegall@google.com \
--cc=dietmar.eggemann@arm.com \
--cc=hdanton@sina.com \
--cc=juri.lelli@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@kernel.org \
--cc=pauld@redhat.com \
--cc=peterz@infradead.org \
--cc=rostedt@goodmis.org \
--cc=valentin.schneider@arm.com \
--cc=vincent.guittot@linaro.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).