From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: Mike Galbraith <efault@gmx.de>
Cc: Thomas Gleixner <tglx@linutronix.de>,
LKML <linux-kernel@vger.kernel.org>,
linux-rt-users <linux-rt-users@vger.kernel.org>,
Steven Rostedt <rostedt@goodmis.org>
Subject: Re: 0087-rcu-Use-a-raw_spinlock_t-for-kfree-batching.patch
Date: Wed, 15 Apr 2020 15:34:23 +0200 [thread overview]
Message-ID: <20200415133423.7mohynwqanoiqzkx@linutronix.de> (raw)
In-Reply-To: <1586062423.4816.15.camel@gmx.de>
On 2020-04-05 06:53:43 [+0200], Mike Galbraith wrote:
> Hi Sebastian,
Hi Mike,
> Just a heads up wrt $subject...
>
> I had done the same in my 5.6 tree, but then 5.7 came along, and I had
> to revisit due to 34c881745549e adding an allocation under that lock
> with irqs disabled. The same commit that added the lock added this.
>
> local_irq_save(flags); // For safely calling this_cpu_ptr().
>
> Whacking that instead of converting the lock cures 5.6 and 5.7 woes.
So I think you are telling me that I made the lock raw and then they
added in v5.7 a __get_free_page() call in
kfree_call_rcu_add_ptr_to_bulk() which is invoked from the free path.
This is indeed not something that made me happy. Now let me think about
this for a moment…
> -Mike
Sebastian
next prev parent reply other threads:[~2020-04-15 13:34 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-03 17:04 [ANNOUNCE] v5.6.2-rt1 Sebastian Andrzej Siewior
2020-04-05 4:53 ` 0087-rcu-Use-a-raw_spinlock_t-for-kfree-batching.patch Mike Galbraith
2020-04-15 13:34 ` Sebastian Andrzej Siewior [this message]
2020-04-08 7:00 ` [ANNOUNCE] v5.6.2-rt1 Juri Lelli
2020-04-15 11:12 ` Sebastian Andrzej Siewior
2020-04-15 13:37 ` Juri Lelli
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