From: "tip-bot2 for Abel Wu" <tip-bot2@linutronix.de>
To: linux-tip-commits@vger.kernel.org
Cc: Abel Wu <wuyun.abel@bytedance.com>,
"Peter Zijlstra (Intel)" <peterz@infradead.org>,
Josh Don <joshdon@google.com>,
Mel Gorman <mgorman@techsingularity.net>,
x86@kernel.org, linux-kernel@vger.kernel.org
Subject: [tip: sched/core] sched/fair: Default to false in test_idle_cores()
Date: Fri, 09 Sep 2022 09:00:28 -0000 [thread overview]
Message-ID: <166271402832.401.6641123344828384147.tip-bot2@tip-bot2> (raw)
In-Reply-To: <20220907112000.1854-5-wuyun.abel@bytedance.com>
The following commit has been merged into the sched/core branch of tip:
Commit-ID: 398ba2b0cc0a43964fe3d2dd19cb2a478f1f220b
Gitweb: https://git.kernel.org/tip/398ba2b0cc0a43964fe3d2dd19cb2a478f1f220b
Author: Abel Wu <wuyun.abel@bytedance.com>
AuthorDate: Wed, 07 Sep 2022 19:19:59 +08:00
Committer: Peter Zijlstra <peterz@infradead.org>
CommitterDate: Wed, 07 Sep 2022 21:53:47 +02:00
sched/fair: Default to false in test_idle_cores()
It's uncertain whether idle cores exist or not if shared sched-
domains are not ready, so returning "no idle cores" usually
makes sense.
While __update_idle_core() is an exception, it checks status
of this core and set hint to shared sched-domain if necessary.
So the whole logic of this function depends on the existence
of shared sched-domain, and can certainly bail out early if
it is not available.
It's somehow a little tricky, and as Josh suggested that it
should be transient while the domain isn't ready. So remove
the self-defined default value to make things more clearer.
Signed-off-by: Abel Wu <wuyun.abel@bytedance.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Josh Don <joshdon@google.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Link: https://lore.kernel.org/r/20220907112000.1854-5-wuyun.abel@bytedance.com
---
kernel/sched/fair.c | 16 ++++++++--------
1 file changed, 8 insertions(+), 8 deletions(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 03ce650..23b020c 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -1588,11 +1588,11 @@ numa_type numa_classify(unsigned int imbalance_pct,
#ifdef CONFIG_SCHED_SMT
/* Forward declarations of select_idle_sibling helpers */
-static inline bool test_idle_cores(int cpu, bool def);
+static inline bool test_idle_cores(int cpu);
static inline int numa_idle_core(int idle_core, int cpu)
{
if (!static_branch_likely(&sched_smt_present) ||
- idle_core >= 0 || !test_idle_cores(cpu, false))
+ idle_core >= 0 || !test_idle_cores(cpu))
return idle_core;
/*
@@ -6271,7 +6271,7 @@ static inline void set_idle_cores(int cpu, int val)
WRITE_ONCE(sds->has_idle_cores, val);
}
-static inline bool test_idle_cores(int cpu, bool def)
+static inline bool test_idle_cores(int cpu)
{
struct sched_domain_shared *sds;
@@ -6279,7 +6279,7 @@ static inline bool test_idle_cores(int cpu, bool def)
if (sds)
return READ_ONCE(sds->has_idle_cores);
- return def;
+ return false;
}
/*
@@ -6295,7 +6295,7 @@ void __update_idle_core(struct rq *rq)
int cpu;
rcu_read_lock();
- if (test_idle_cores(core, true))
+ if (test_idle_cores(core))
goto unlock;
for_each_cpu(cpu, cpu_smt_mask(core)) {
@@ -6367,9 +6367,9 @@ static inline void set_idle_cores(int cpu, int val)
{
}
-static inline bool test_idle_cores(int cpu, bool def)
+static inline bool test_idle_cores(int cpu)
{
- return def;
+ return false;
}
static inline int select_idle_core(struct task_struct *p, int core, struct cpumask *cpus, int *idle_cpu)
@@ -6608,7 +6608,7 @@ static int select_idle_sibling(struct task_struct *p, int prev, int target)
return target;
if (sched_smt_active()) {
- has_idle_core = test_idle_cores(target, false);
+ has_idle_core = test_idle_cores(target);
if (!has_idle_core && cpus_share_cache(prev, target)) {
i = select_idle_smt(p, prev);
next prev parent reply other threads:[~2022-09-09 9:02 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-07 11:19 [PATCH v4 0/5] sched/fair: Minor SIS optimizations Abel Wu
2022-09-07 11:19 ` [PATCH v4 1/5] sched/fair: Remove redundant check in select_idle_smt() Abel Wu
2022-09-09 9:00 ` [tip: sched/core] " tip-bot2 for Abel Wu
2022-09-07 11:19 ` [PATCH v4 2/5] sched/fair: Avoid double search on same cpu Abel Wu
2022-09-09 9:00 ` [tip: sched/core] " tip-bot2 for Abel Wu
2022-09-07 11:19 ` [PATCH v4 3/5] sched/fair: Remove useless check in select_idle_core() Abel Wu
2022-09-09 9:00 ` [tip: sched/core] " tip-bot2 for Abel Wu
2022-09-07 11:19 ` [PATCH v4 4/5] sched/fair: Default to false in test_idle_cores() Abel Wu
2022-09-09 9:00 ` tip-bot2 for Abel Wu [this message]
2022-09-07 11:20 ` [PATCH v4 5/5] sched/fair: Cleanup for SIS_PROP Abel Wu
2022-09-09 9:00 ` [tip: sched/core] " tip-bot2 for Abel Wu
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=166271402832.401.6641123344828384147.tip-bot2@tip-bot2 \
--to=tip-bot2@linutronix.de \
--cc=joshdon@google.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-tip-commits@vger.kernel.org \
--cc=mgorman@techsingularity.net \
--cc=peterz@infradead.org \
--cc=wuyun.abel@bytedance.com \
--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).