From: Peter Zijlstra <peterz@infradead.org>
To: mingo@kernel.org, tglx@linutronix.de
Cc: linux-kernel@vger.kernel.org, peterz@infradead.org,
rostedt@goodmis.org, bigeasy@linutronix.de, efault@gmx.de,
max.byungchul.park@gmail.com
Subject: [PATCH 6/7] smp/hotplug: Differentiate the AP-work lockdep class between up and down
Date: Wed, 20 Sep 2017 19:00:20 +0200 [thread overview]
Message-ID: <20170920170546.922524234@infradead.org> (raw)
In-Reply-To: 20170920170014.548896195@infradead.org
[-- Attachment #1: peterz-hotplug-4.patch --]
[-- Type: text/plain, Size: 3088 bytes --]
With lockdep-crossrelease we get deadlock reports that span cpu-up and
cpu-down chains. Such deadlocks cannot possibly happen because cpu-up
and cpu-down are globally serialized.
CPU0 CPU1 CPU2
cpuhp_up_callbacks: takedown_cpu: cpuhp_thread_fun:
cpuhp_state
irq_lock_sparse()
irq_lock_sparse()
wait_for_completion()
cpuhp_state
complete()
Now that we have consistent AP state, we can trivially separate the
AP-work class between up and down using st->bringup.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
kernel/cpu.c | 41 ++++++++++++++++++++++++++++++++---------
1 file changed, 32 insertions(+), 9 deletions(-)
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -68,9 +68,26 @@ struct cpuhp_cpu_state {
static DEFINE_PER_CPU(struct cpuhp_cpu_state, cpuhp_state);
#if defined(CONFIG_LOCKDEP) && defined(CONFIG_SMP)
-static struct lock_class_key cpuhp_state_key;
-static struct lockdep_map cpuhp_state_lock_map =
- STATIC_LOCKDEP_MAP_INIT("cpuhp_state", &cpuhp_state_key);
+static struct lockdep_map cpuhp_state_up_map =
+ STATIC_LOCKDEP_MAP_INIT("cpuhp_state-up", &cpuhp_state_up_map);
+static struct lockdep_map cpuhp_state_down_map =
+ STATIC_LOCKDEP_MAP_INIT("cpuhp_state-down", &cpuhp_state_down_map);
+
+
+static void inline cpuhp_lock_acquire(bool bringup)
+{
+ lock_map_acquire(bringup ? &cpuhp_state_up_map : &cpuhp_state_down_map);
+}
+
+static void inline cpuhp_lock_release(bool bringup)
+{
+ lock_map_release(bringup ? &cpuhp_state_up_map : &cpuhp_state_down_map);
+}
+#else
+
+static void inline cpuhp_lock_acquire(bool bringup) { }
+static void inline cpuhp_lock_release(bool bringup) { }
+
#endif
/**
@@ -512,7 +529,7 @@ static void cpuhp_thread_fun(unsigned in
if (WARN_ON_ONCE(!st->should_run))
return;
- lock_map_acquire(&cpuhp_state_lock_map);
+ cpuhp_lock_acquire(bringup);
if (st->single) {
state = st->cb_state;
@@ -564,7 +581,7 @@ static void cpuhp_thread_fun(unsigned in
}
next:
- lock_map_release(&cpuhp_state_lock_map);
+ cpuhp_lock_release(bringup);
if (!st->should_run)
complete(&st->done);
@@ -581,8 +598,11 @@ cpuhp_invoke_ap_callback(int cpu, enum c
if (!cpu_online(cpu))
return 0;
- lock_map_acquire(&cpuhp_state_lock_map);
- lock_map_release(&cpuhp_state_lock_map);
+ cpuhp_lock_acquire(false);
+ cpuhp_lock_release(false);
+
+ cpuhp_lock_acquire(true);
+ cpuhp_lock_release(true);
/*
* If we are up and running, use the hotplug thread. For early calls
@@ -620,8 +640,11 @@ static int cpuhp_kick_ap_work(unsigned i
enum cpuhp_state prev_state = st->state;
int ret;
- lock_map_acquire(&cpuhp_state_lock_map);
- lock_map_release(&cpuhp_state_lock_map);
+ cpuhp_lock_acquire(false);
+ cpuhp_lock_release(false);
+
+ cpuhp_lock_acquire(true);
+ cpuhp_lock_release(true);
trace_cpuhp_enter(cpu, st->target, prev_state, cpuhp_kick_ap_work);
ret = cpuhp_kick_ap(st, st->target);
next prev parent reply other threads:[~2017-09-20 17:08 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-20 17:00 [PATCH 0/7] smp/hotplug rework / lockdep annotate Peter Zijlstra
2017-09-20 17:00 ` [PATCH 1/7] smp/hotplug: Add state diagram Peter Zijlstra
2017-09-20 17:00 ` [PATCH 2/7] smp/hotplug: Allow external multi-instance rollback Peter Zijlstra
2017-09-20 17:00 ` [PATCH 3/7] smp/hotplug: Rewrite AP state machine core Peter Zijlstra
2017-09-20 17:00 ` [PATCH 4/7] smp/hotplug: Callback vs state-machine consistency Peter Zijlstra
2017-09-20 17:00 ` [PATCH 5/7] smp/hotplug: Differentiate the AP completion between up and down Peter Zijlstra
2017-09-25 8:49 ` Byungchul Park
2017-09-20 17:00 ` Peter Zijlstra [this message]
2017-09-25 8:54 ` [PATCH 6/7] smp/hotplug: Differentiate the AP-work lockdep class " Byungchul Park
2017-09-25 9:16 ` Peter Zijlstra
2017-11-30 14:43 ` Lai Jiangshan
2017-09-20 17:00 ` [PATCH 7/7] smp/hotplug: Hotplug state fail injection Peter Zijlstra
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=20170920170546.922524234@infradead.org \
--to=peterz@infradead.org \
--cc=bigeasy@linutronix.de \
--cc=efault@gmx.de \
--cc=linux-kernel@vger.kernel.org \
--cc=max.byungchul.park@gmail.com \
--cc=mingo@kernel.org \
--cc=rostedt@goodmis.org \
--cc=tglx@linutronix.de \
/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).