From: "tip-bot2 for Mel Gorman" <tip-bot2@linutronix.de>
To: linux-tip-commits@vger.kernel.org
Cc: Mel Gorman <mgorman@techsingularity.net>,
Ingo Molnar <mingo@kernel.org>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
Vincent Guittot <vincent.guittot@linaro.org>,
Juri Lelli <juri.lelli@redhat.com>,
Dietmar Eggemann <dietmar.eggemann@arm.com>,
Steven Rostedt <rostedt@goodmis.org>,
Valentin Schneider <valentin.schneider@arm.com>,
Phil Auld <pauld@redhat.com>, Hillf Danton <hdanton@sina.com>,
x86 <x86@kernel.org>, LKML <linux-kernel@vger.kernel.org>
Subject: [tip: sched/core] sched/numa: Stop an exhastive search if a reasonable swap candidate or idle CPU is found
Date: Mon, 24 Feb 2020 15:20:29 -0000 [thread overview]
Message-ID: <158255762967.28353.14025771290351307714.tip-bot2@tip-bot2> (raw)
In-Reply-To: <20200224095223.13361-14-mgorman@techsingularity.net>
The following commit has been merged into the sched/core branch of tip:
Commit-ID: a0f03b617c3b2644d3d47bf7d9e60aed01bd5b10
Gitweb: https://git.kernel.org/tip/a0f03b617c3b2644d3d47bf7d9e60aed01bd5b10
Author: Mel Gorman <mgorman@techsingularity.net>
AuthorDate: Mon, 24 Feb 2020 09:52:23
Committer: Ingo Molnar <mingo@kernel.org>
CommitterDate: Mon, 24 Feb 2020 11:36:40 +01:00
sched/numa: Stop an exhastive search if a reasonable swap candidate or idle CPU is found
When domains are imbalanced or overloaded a search of all CPUs on the
target domain is searched and compared with task_numa_compare. In some
circumstances, a candidate is found that is an obvious win.
o A task can move to an idle CPU and an idle CPU is found
o A swap candidate is found that would move to its preferred domain
This patch terminates the search when either condition is met.
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Valentin Schneider <valentin.schneider@arm.com>
Cc: Phil Auld <pauld@redhat.com>
Cc: Hillf Danton <hdanton@sina.com>
Link: https://lore.kernel.org/r/20200224095223.13361-14-mgorman@techsingularity.net
---
kernel/sched/fair.c | 31 +++++++++++++++++++++++++++----
1 file changed, 27 insertions(+), 4 deletions(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 8c1ac01..fcc9686 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -1707,7 +1707,7 @@ static bool load_too_imbalanced(long src_load, long dst_load,
* into account that it might be best if task running on the dst_cpu should
* be exchanged with the source task
*/
-static void task_numa_compare(struct task_numa_env *env,
+static bool task_numa_compare(struct task_numa_env *env,
long taskimp, long groupimp, bool maymove)
{
struct numa_group *cur_ng, *p_ng = deref_curr_numa_group(env->p);
@@ -1718,9 +1718,10 @@ static void task_numa_compare(struct task_numa_env *env,
int dist = env->dist;
long moveimp = imp;
long load;
+ bool stopsearch = false;
if (READ_ONCE(dst_rq->numa_migrate_on))
- return;
+ return false;
rcu_read_lock();
cur = rcu_dereference(dst_rq->curr);
@@ -1731,8 +1732,10 @@ static void task_numa_compare(struct task_numa_env *env,
* Because we have preemption enabled we can get migrated around and
* end try selecting ourselves (current == env->p) as a swap candidate.
*/
- if (cur == env->p)
+ if (cur == env->p) {
+ stopsearch = true;
goto unlock;
+ }
if (!cur) {
if (maymove && moveimp >= env->best_imp)
@@ -1860,8 +1863,27 @@ assign:
}
task_numa_assign(env, cur, imp);
+
+ /*
+ * If a move to idle is allowed because there is capacity or load
+ * balance improves then stop the search. While a better swap
+ * candidate may exist, a search is not free.
+ */
+ if (maymove && !cur && env->best_cpu >= 0 && idle_cpu(env->best_cpu))
+ stopsearch = true;
+
+ /*
+ * If a swap candidate must be identified and the current best task
+ * moves its preferred node then stop the search.
+ */
+ if (!maymove && env->best_task &&
+ env->best_task->numa_preferred_nid == env->src_nid) {
+ stopsearch = true;
+ }
unlock:
rcu_read_unlock();
+
+ return stopsearch;
}
static void task_numa_find_cpu(struct task_numa_env *env,
@@ -1916,7 +1938,8 @@ static void task_numa_find_cpu(struct task_numa_env *env,
continue;
env->dst_cpu = cpu;
- task_numa_compare(env, taskimp, groupimp, maymove);
+ if (task_numa_compare(env, taskimp, groupimp, maymove))
+ break;
}
}
next prev parent reply other threads:[~2020-02-24 15:21 UTC|newest]
Thread overview: 83+ 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 ` [PATCH 11/13] sched/numa: Find an alternative idle CPU if the CPU is part of an active NUMA balance Mel Gorman
2020-02-24 15:20 ` [tip: sched/core] " 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-bot2 for Mel Gorman [this message]
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
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=158255762967.28353.14025771290351307714.tip-bot2@tip-bot2 \
--to=tip-bot2@linutronix.de \
--cc=a.p.zijlstra@chello.nl \
--cc=dietmar.eggemann@arm.com \
--cc=hdanton@sina.com \
--cc=juri.lelli@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-tip-commits@vger.kernel.org \
--cc=mgorman@techsingularity.net \
--cc=mingo@kernel.org \
--cc=pauld@redhat.com \
--cc=rostedt@goodmis.org \
--cc=valentin.schneider@arm.com \
--cc=vincent.guittot@linaro.org \
--cc=x86@kernel.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).