From: Peter Zijlstra <peterz@infradead.org>
To: Waiman Long <longman@redhat.com>
Cc: Ingo Molnar <mingo@redhat.com>, Will Deacon <will.deacon@arm.com>,
linux-kernel@vger.kernel.org,
Bart Van Assche <bvanassche@acm.org>
Subject: Re: [PATCH v5 6/7] locking/lockdep: Reuse freed chain_hlocks entries
Date: Wed, 5 Feb 2020 10:41:53 +0100 [thread overview]
Message-ID: <20200205094153.GH14879@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <8fd7ce61-d8eb-6bde-7d41-54b9920e3e39@redhat.com>
On Tue, Feb 04, 2020 at 11:45:15AM -0500, Waiman Long wrote:
> On 2/4/20 7:36 AM, Peter Zijlstra wrote:
> > --- a/kernel/locking/lockdep_proc.c
> > +++ b/kernel/locking/lockdep_proc.c
> > @@ -278,9 +278,11 @@ static int lockdep_stats_show(struct seq
> > #ifdef CONFIG_PROVE_LOCKING
> > seq_printf(m, " dependency chains: %11lu [max: %lu]\n",
> > lock_chain_count(), MAX_LOCKDEP_CHAINS);
> > - seq_printf(m, " dependency chain hlocks: %11lu [max: %lu]\n",
> > - MAX_LOCKDEP_CHAIN_HLOCKS - nr_free_chain_hlocks,
> > + seq_printf(m, " dependency chain hlocks used: %11lu [max: %lu]\n",
> > + MAX_LOCKDEP_CHAIN_HLOCKS - (nr_free_chain_hlocks - nr_lost_chain_hlocks),
> > MAX_LOCKDEP_CHAIN_HLOCKS);
> > + seq_printf(m, " dependency chain hlocks free: %11lu\n", nr_free_chain_hlocks);
> > + seq_printf(m, " dependency chain hlocks lost: %11lu\n", nr_lost_chain_hlocks);
>
> I do have some comments on this. There are three buckets now - free,
> lost, used. They add up to MAX_LOCKDEP_CHAIN_HLOCKS. I don't think we
> need to list all three. We can compute the third one by subtracting max
> from the other two.
>
> Something like:
>
> diff --git a/kernel/locking/lockdep_proc.c b/kernel/locking/lockdep_proc.c
> index 14932ea50317..6fe6a21c58d3 100644
> --- a/kernel/locking/lockdep_proc.c
> +++ b/kernel/locking/lockdep_proc.c
> @@ -278,9 +278,12 @@ static int lockdep_stats_show(struct seq_file *m,
> void *v)
> #ifdef CONFIG_PROVE_LOCKING
> seq_printf(m, " dependency chains: %11lu [max: %lu]\n",
> lock_chain_count(), MAX_LOCKDEP_CHAINS);
> - seq_printf(m, " dependency chain hlocks: %11lu [max: %lu]\n",
> - MAX_LOCKDEP_CHAIN_HLOCKS - nr_free_chain_hlocks,
> + seq_printf(m, " dependency chain hlocks used: %11lu [max: %lu]\n",
> + MAX_LOCKDEP_CHAIN_HLOCKS -
> + (nr_free_chain_hlocks + nr_lost_chain_hlocks),
> MAX_LOCKDEP_CHAIN_HLOCKS);
> + seq_printf(m, " dependency chain hlocks lost: %11lu\n",
> + nr_lost_chain_hlocks);
> #endif
>
Sure, also I tihnk the compiler is unhappy about %lu vs 'unsigned int'
for some of them.
next prev parent reply other threads:[~2020-02-05 9:42 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-03 16:41 [PATCH v5 0/7] locking/lockdep: Reuse zapped " Waiman Long
2020-02-03 16:41 ` [PATCH v5 1/7] locking/lockdep: Decrement irq context counters when removing lock chain Waiman Long
2020-02-03 16:41 ` [PATCH v5 2/7] locking/lockdep: Display irq_context names in /proc/lockdep_chains Waiman Long
2020-02-03 16:41 ` [PATCH v5 3/7] locking/lockdep: Track number of zapped classes Waiman Long
2020-02-03 16:41 ` [PATCH v5 4/7] locking/lockdep: Throw away all lock chains with zapped class Waiman Long
2020-02-03 16:41 ` [PATCH v5 5/7] locking/lockdep: Track number of zapped lock chains Waiman Long
2020-02-03 16:41 ` [PATCH v5 6/7] locking/lockdep: Reuse freed chain_hlocks entries Waiman Long
2020-02-04 12:36 ` Peter Zijlstra
2020-02-04 14:54 ` Waiman Long
2020-02-04 16:45 ` Waiman Long
2020-02-05 9:41 ` Peter Zijlstra [this message]
2020-02-05 13:59 ` Waiman Long
2020-02-04 15:42 ` Peter Zijlstra
2020-02-04 16:12 ` Waiman Long
2020-02-04 16:26 ` Waiman Long
2020-02-04 16:57 ` Waiman Long
2020-02-05 9:48 ` Peter Zijlstra
2020-02-05 14:03 ` Waiman Long
2020-02-03 16:41 ` [PATCH v5 7/7] locking/lockdep: Add a fast path for chain_hlocks allocation Waiman Long
2020-02-04 12:47 ` Peter Zijlstra
2020-02-04 15:07 ` Waiman Long
2020-02-04 13:18 ` Peter Zijlstra
2020-02-04 13:44 ` Peter Zijlstra
2020-02-04 18:02 ` Waiman Long
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