From: Steven Rostedt <rostedt@goodmis.org>
To: linux-kernel@vger.kernel.org,
linux-rt-users <linux-rt-users@vger.kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Carsten Emde <C.Emde@osadl.org>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
John Kacur <jkacur@redhat.com>,
Paul Gortmaker <paul.gortmaker@windriver.com>,
Mike Galbraith <umgwanakikbuti@gmail.com>
Subject: [PATCH RT 06/22] preempt-lazy: Add the lazy-preemption check to preempt_schedule()
Date: Wed, 02 Mar 2016 10:09:05 -0500 [thread overview]
Message-ID: <20160302151111.214477863@goodmis.org> (raw)
In-Reply-To: 20160302150859.204542604@goodmis.org
[-- Attachment #1: 0006-preempt-lazy-Add-the-lazy-preemption-check-to-preemp.patch --]
[-- Type: text/plain, Size: 2058 bytes --]
4.1.15-rt18-rc1 stable review patch.
If anyone has any objections, please let me know.
------------------
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Probably in the rebase onto v4.1 this check got moved into less commonly used
preempt_schedule_notrace(). This patch ensures that both functions use it.
Reported-by: Mike Galbraith <umgwanakikbuti@gmail.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
kernel/sched/core.c | 36 ++++++++++++++++++++++++++++--------
1 file changed, 28 insertions(+), 8 deletions(-)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index d21091f2fd1f..5cbfb0548574 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -3116,6 +3116,30 @@ static void __sched notrace preempt_schedule_common(void)
} while (need_resched());
}
+#ifdef CONFIG_PREEMPT_LAZY
+/*
+ * If TIF_NEED_RESCHED is then we allow to be scheduled away since this is
+ * set by a RT task. Oterwise we try to avoid beeing scheduled out as long as
+ * preempt_lazy_count counter >0.
+ */
+static int preemptible_lazy(void)
+{
+ if (test_thread_flag(TIF_NEED_RESCHED))
+ return 1;
+ if (current_thread_info()->preempt_lazy_count)
+ return 0;
+ return 1;
+}
+
+#else
+
+static int preemptible_lazy(void)
+{
+ return 1;
+}
+
+#endif
+
#ifdef CONFIG_PREEMPT
/*
* this is the entry point to schedule() from in-kernel preemption
@@ -3130,6 +3154,8 @@ asmlinkage __visible void __sched notrace preempt_schedule(void)
*/
if (likely(!preemptible()))
return;
+ if (!preemptible_lazy())
+ return;
preempt_schedule_common();
}
@@ -3157,15 +3183,9 @@ asmlinkage __visible void __sched notrace preempt_schedule_context(void)
if (likely(!preemptible()))
return;
-
-#ifdef CONFIG_PREEMPT_LAZY
- /*
- * Check for lazy preemption
- */
- if (current_thread_info()->preempt_lazy_count &&
- !test_thread_flag(TIF_NEED_RESCHED))
+ if (!preemptible_lazy())
return;
-#endif
+
do {
__preempt_count_add(PREEMPT_ACTIVE);
/*
--
2.7.0
next prev parent reply other threads:[~2016-03-02 15:09 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-02 15:08 [PATCH RT 00/22] Linux 4.1.15-rt18-rc1 Steven Rostedt
2016-03-02 15:09 ` [PATCH RT 01/22] sched: reset tasks lockless wake-queues on fork() Steven Rostedt
2016-03-02 15:09 ` [PATCH RT 02/22] ptrace: dont open IRQs in ptrace_freeze_traced() too early Steven Rostedt
2016-03-02 15:09 ` [PATCH RT 03/22] net: move xmit_recursion to per-task variable on -RT Steven Rostedt
2016-03-02 15:09 ` [PATCH RT 04/22] kernel/softirq: use cond_resched_rcu_qs() on -RT as well (run_ksoftirqd()) Steven Rostedt
2016-03-02 15:09 ` [PATCH RT 05/22] net/core: protect users of napi_alloc_cache against reentrance Steven Rostedt
2016-03-02 15:09 ` Steven Rostedt [this message]
2016-03-02 15:09 ` [PATCH RT 07/22] softirq: split timer softirqs out of ksoftirqd Steven Rostedt
2016-03-02 15:09 ` [PATCH RT 08/22] net: provide a way to delegate processing a softirq to ksoftirqd Steven Rostedt
2016-03-02 15:09 ` [PATCH RT 09/22] latencyhist: disable jump-labels Steven Rostedt
2016-03-02 15:09 ` [PATCH RT 10/22] arm64: replace read_lock to rcu lock in call_step_hook Steven Rostedt
2016-03-02 15:09 ` [PATCH RT 11/22] kernel: migrate_disable() do fastpath in atomic & irqs-off Steven Rostedt
2016-03-02 15:09 ` [PATCH RT 12/22] kernel: softirq: unlock with irqs on Steven Rostedt
2016-03-02 15:09 ` [PATCH RT 13/22] kernel/stop_machine: partly revert "stop_machine: Use raw spinlocks" Steven Rostedt
2016-03-02 15:09 ` [PATCH RT 14/22] tick/broadcast: Make broadcast hrtimer irqsafe Steven Rostedt
2016-03-02 15:09 ` [PATCH RT 15/22] sched,rt: __always_inline preemptible_lazy() Steven Rostedt
2016-03-02 15:09 ` [PATCH RT 16/22] drm,radeon,i915: Use preempt_disable/enable_rt() where recommended Steven Rostedt
2016-03-02 15:09 ` [PATCH RT 17/22] drm,i915: Use local_lock/unlock_irq() in intel_pipe_update_start/end() Steven Rostedt
2016-03-02 15:09 ` [PATCH RT 18/22] trace: Use rcuidle version for preemptoff_hist trace point Steven Rostedt
2016-03-02 15:09 ` [PATCH RT 19/22] f2fs: Mutex cant be used by down_write_nest_lock() Steven Rostedt
2016-03-02 15:09 ` [PATCH RT 20/22] rcu/torture: Comment out rcu_bh ops on PREEMPT_RT_FULL Steven Rostedt
2016-03-02 15:09 ` [PATCH RT 21/22] kernel: sched: Fix preempt_disable_ip recodring for preempt_disable() Steven Rostedt
2016-03-02 15:09 ` [PATCH RT 22/22] Linux 4.1.15-rt18-rc1 Steven Rostedt
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=20160302151111.214477863@goodmis.org \
--to=rostedt@goodmis.org \
--cc=C.Emde@osadl.org \
--cc=bigeasy@linutronix.de \
--cc=jkacur@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-rt-users@vger.kernel.org \
--cc=paul.gortmaker@windriver.com \
--cc=tglx@linutronix.de \
--cc=umgwanakikbuti@gmail.com \
/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).