From: "pang.xunlei" <pang.xunlei@linaro.org>
To: linux-kernel@vger.kernel.org
Cc: Peter Zijlstra <peterz@infradead.org>,
Steven Rostedt <rostedt@goodmis.org>,
Juri Lelli <juri.lelli@gmail.com>,
"pang.xunlei" <pang.xunlei@linaro.org>
Subject: [PATCH v2 4/4] sched/deadline: change cpudl_find() to return bool instead of best_cpu
Date: Wed, 19 Nov 2014 23:46:22 +0800 [thread overview]
Message-ID: <1416411982-1204-4-git-send-email-pang.xunlei@linaro.org> (raw)
In-Reply-To: <1416411982-1204-1-git-send-email-pang.xunlei@linaro.org>
cpudl_find() is not a good place to select the best cpu, so leave
this role to its call site, currently it is find_later_rq() where
we can do the election of the best cpu according to sd topology.
Signed-off-by: pang.xunlei <pang.xunlei@linaro.org>
---
kernel/sched/cpudeadline.c | 15 +++++----------
kernel/sched/deadline.c | 17 ++++++-----------
2 files changed, 11 insertions(+), 21 deletions(-)
diff --git a/kernel/sched/cpudeadline.c b/kernel/sched/cpudeadline.c
index 3047846..41d3578 100644
--- a/kernel/sched/cpudeadline.c
+++ b/kernel/sched/cpudeadline.c
@@ -100,29 +100,24 @@ static inline int cpudl_maximum(struct cpudl *cp)
* @later_mask: a mask to fill in with the selected CPUs (not NULL)
* @set_flag: indicate if later_mask should be set
*
- * Returns: int - best CPU (heap maximum if suitable)
+ * Return: (int)bool - CPUs were found
*/
int cpudl_find(struct cpudl *cp, struct task_struct *p,
struct cpumask *later_mask, int set_flag)
{
- int best_cpu = -1;
const struct sched_dl_entity *dl_se = &p->dl;
cpumask_and(later_mask, cpu_active_mask, &p->cpus_allowed);
if (cpumask_and(later_mask, later_mask, cp->free_cpus)) {
- best_cpu = cpumask_any(later_mask);
- goto out;
+ return 1;
} else if (cpumask_test_cpu(cpudl_maximum(cp), &p->cpus_allowed) &&
dl_time_before(dl_se->deadline, cp->elements[0].dl)) {
- best_cpu = cpudl_maximum(cp);
if (set_flag)
- cpumask_set_cpu(best_cpu, later_mask);
+ cpumask_set_cpu(cpudl_maximum(cp), later_mask);
+ return 1;
}
-out:
- WARN_ON(best_cpu != -1 && !cpu_present(best_cpu));
-
- return best_cpu;
+ return 0;
}
/*
diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
index e8208d0..3e82cf3 100644
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -976,7 +976,7 @@ static void check_preempt_equal_dl(struct rq *rq, struct task_struct *p)
* let's hope p can move out.
*/
if (rq->curr->nr_cpus_allowed == 1 ||
- cpudl_find(&rq->rd->cpudl, rq->curr, later_mask, 0) == -1)
+ !cpudl_find(&rq->rd->cpudl, rq->curr, later_mask, 0))
return;
/*
@@ -984,7 +984,7 @@ static void check_preempt_equal_dl(struct rq *rq, struct task_struct *p)
* see if it is pushed or pulled somewhere else.
*/
if (p->nr_cpus_allowed != 1 &&
- cpudl_find(&rq->rd->cpudl, p, later_mask, 0) != -1)
+ cpudl_find(&rq->rd->cpudl, p, later_mask, 0))
return;
resched_curr(rq);
@@ -1189,9 +1189,7 @@ static int find_later_rq(struct task_struct *task)
* We have to consider system topology and task affinity
* first, then we can look for a suitable cpu.
*/
- best_cpu = cpudl_find(&task_rq(task)->rd->cpudl,
- task, later_mask, 1);
- if (best_cpu == -1)
+ if (!cpudl_find(&task_rq(task)->rd->cpudl, task, later_mask, 1))
return -1;
/*
@@ -1230,12 +1228,9 @@ static int find_later_rq(struct task_struct *task)
return this_cpu;
}
- /*
- * Last chance: if best_cpu is valid and is
- * in the mask, that becomes our choice.
- */
- if (best_cpu < nr_cpu_ids &&
- cpumask_test_cpu(best_cpu, sched_domain_span(sd))) {
+ best_cpu = cpumask_first_and(lowest_mask,
+ sched_domain_span(sd));
+ if (best_cpu < nr_cpu_ids) {
rcu_read_unlock();
return best_cpu;
}
--
1.7.9.5
next prev parent reply other threads:[~2014-11-19 15:47 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-11-19 15:46 [PATCH v2 1/4] sched/deadline: Modify cpudl.free_cpus to reflect rd->span pang.xunlei
2014-11-19 15:46 ` [PATCH v2 2/4] sched/deadline: Fix wrong cpudl_find() in check_preempt_equal_dl() pang.xunlei
2014-11-19 15:46 ` [PATCH v2 3/4] sched/deadline: add the "set_flag" argument to cpudl_find() pang.xunlei
2014-11-19 16:24 ` Steven Rostedt
2014-11-20 14:58 ` pang.xunlei
2014-11-20 15:06 ` pang.xunlei
2014-11-19 15:46 ` pang.xunlei [this message]
2014-11-19 16:30 ` [PATCH v2 4/4] sched/deadline: change cpudl_find() to return bool instead of best_cpu Steven Rostedt
2014-11-20 9:00 ` [PATCH v2 1/4] sched/deadline: Modify cpudl.free_cpus to reflect rd->span Wanpeng Li
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=1416411982-1204-4-git-send-email-pang.xunlei@linaro.org \
--to=pang.xunlei@linaro.org \
--cc=juri.lelli@gmail.com \
--cc=linux-kernel@vger.kernel.org \
--cc=peterz@infradead.org \
--cc=rostedt@goodmis.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).