From: Peter Zijlstra <peterz@infradead.org>
To: gor@linux.ibm.com, jpoimboe@redhat.com, jikos@kernel.org,
mbenes@suse.cz, pmladek@suse.com, mingo@kernel.org
Cc: linux-kernel@vger.kernel.org, peterz@infradead.org,
joe.lawrence@redhat.com, fweisbec@gmail.com, tglx@linutronix.de,
hca@linux.ibm.com, svens@linux.ibm.com, sumanthk@linux.ibm.com,
live-patching@vger.kernel.org, paulmck@kernel.org
Subject: [RFC][PATCH 5/7] sched,livepatch: Use wake_up_if_idle()
Date: Wed, 22 Sep 2021 13:05:11 +0200 [thread overview]
Message-ID: <20210922110836.185239814@infradead.org> (raw)
In-Reply-To: 20210922110506.703075504@infradead.org
Make sure to prod idle CPUs so they call klp_update_patch_state().
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
kernel/livepatch/transition.c | 16 +++++++++-------
1 file changed, 9 insertions(+), 7 deletions(-)
--- a/kernel/livepatch/transition.c
+++ b/kernel/livepatch/transition.c
@@ -287,21 +287,21 @@ static int klp_check_task(struct task_st
* running, or it's sleeping on a to-be-patched or to-be-unpatched function, or
* if the stack is unreliable, return false.
*/
-static bool klp_try_switch_task(struct task_struct *task)
+static int klp_try_switch_task(struct task_struct *task)
{
const char *old_name;
int ret;
/* check if this task has already switched over */
if (task->patch_state == klp_target_state)
- return true;
+ return 0;
/*
* For arches which don't have reliable stack traces, we have to rely
* on other methods (e.g., switching tasks at kernel exit).
*/
if (!klp_have_reliable_stack())
- return false;
+ return -EINVAL;
/*
* Now try to check the stack for any to-be-patched or to-be-unpatched
@@ -324,7 +324,7 @@ static bool klp_try_switch_task(struct t
break;
}
- return !ret;
+ return ret;
}
/*
@@ -394,7 +394,7 @@ void klp_try_complete_transition(void)
*/
read_lock(&tasklist_lock);
for_each_process_thread(g, task)
- if (!klp_try_switch_task(task))
+ if (klp_try_switch_task(task))
complete = false;
read_unlock(&tasklist_lock);
@@ -405,8 +405,10 @@ void klp_try_complete_transition(void)
for_each_possible_cpu(cpu) {
task = idle_task(cpu);
if (cpu_online(cpu)) {
- if (!klp_try_switch_task(task))
- complete = false;
+ int ret = klp_try_switch_task(task);
+ if (ret == -EBUSY)
+ wake_up_if_idle(cpu);
+ complete = !ret;
} else if (task->patch_state != klp_target_state) {
/* offline idle tasks can be switched immediately */
clear_tsk_thread_flag(task, TIF_PATCH_PENDING);
next prev parent reply other threads:[~2021-09-22 11:16 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-22 11:05 [RFC][PATCH 0/7] sched,rcu,context_tracking,livepatch: Improve livepatch task transitions for idle and NOHZ_FULL cpus Peter Zijlstra
2021-09-22 11:05 ` [RFC][PATCH 1/7] sched,rcu: Rework try_invoke_on_locked_down_task() Peter Zijlstra
2021-09-22 11:05 ` [RFC][PATCH 2/7] sched: Fix task_try_func() Peter Zijlstra
2021-09-22 11:05 ` [RFC][PATCH 3/7] sched,livepatch: Use task_try_func() Peter Zijlstra
2021-09-23 12:05 ` Petr Mladek
2021-09-23 13:17 ` Peter Zijlstra
2021-09-23 13:47 ` Peter Zijlstra
2021-09-22 11:05 ` [RFC][PATCH 4/7] sched: Simplify wake_up_*idle*() Peter Zijlstra
2021-09-22 11:05 ` Peter Zijlstra [this message]
2021-09-22 13:05 ` [RFC][PATCH 5/7] sched,livepatch: Use wake_up_if_idle() Miroslav Benes
2021-09-23 12:19 ` Petr Mladek
2021-09-22 11:05 ` [RFC][PATCH 6/7] context_tracking: Provide SMP ordering using RCU Peter Zijlstra
2021-09-22 15:17 ` Paul E. McKenney
2021-09-22 19:33 ` Peter Zijlstra
2021-09-22 19:47 ` Peter Zijlstra
2021-09-22 19:59 ` Paul E. McKenney
2021-09-22 19:53 ` Paul E. McKenney
2021-09-22 20:02 ` Peter Zijlstra
2021-09-23 12:10 ` Petr Mladek
2021-09-24 18:57 ` Joel Savitz
2021-09-27 14:33 ` Petr Mladek
2021-09-22 11:05 ` [RFC][PATCH 7/7] livepatch,context_tracking: Avoid disturbing NOHZ_FULL tasks Peter Zijlstra
2021-09-23 13:14 ` Petr Mladek
2021-09-23 13:28 ` Peter Zijlstra
2021-09-24 7:33 ` Petr Mladek
2021-09-23 13:22 ` [RFC][PATCH 0/7] sched,rcu,context_tracking,livepatch: Improve livepatch task transitions for idle and NOHZ_FULL cpus Petr Mladek
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