From: Pavel Begunkov <asml.silence@gmail.com>
To: Tejun Heo <tj@kernel.org>
Cc: linux-block@vger.kernel.org, Jens Axboe <axboe@kernel.dk>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
Christoph Lameter <cl@linux.com>, Dennis Zhou <dennis@kernel.org>
Subject: Re: [PATCH 1/2] percpu_ref: percpu_ref_tryget_live() version holding RCU
Date: Thu, 21 Oct 2021 09:41:19 +0100 [thread overview]
Message-ID: <e7319f50-999b-2540-62f1-201afcb29bf3@gmail.com> (raw)
In-Reply-To: <YXB3n2pxiKYbd2Il@slm.duckdns.org>
On 10/20/21 21:10, Tejun Heo wrote:
> On Wed, Oct 20, 2021 at 09:03:18PM +0100, Pavel Begunkov wrote:
>> +/**
>> + * percpu_ref_tryget_live_rcu - same as percpu_ref_tryget_live() but the
>> + * caller is responsible for taking RCU.
>> + *
>> + * This function is safe to call as long as @ref is between init and exit.
>> + */
>> +static inline bool percpu_ref_tryget_live_rcu(struct percpu_ref *ref)
>> +{
>> + unsigned long __percpu *percpu_count;
>> + bool ret = false;
>> +
>> + if (likely(__ref_is_percpu(ref, &percpu_count))) {
>> + this_cpu_inc(*percpu_count);
>> + ret = true;
>> + } else if (!(ref->percpu_count_ptr & __PERCPU_REF_DEAD)) {
>> + ret = atomic_long_inc_not_zero(&ref->data->count);
>> + }
>> + return ret;
>> +}
>
> Can we please add rcu_read_lock_held() assertion? Other than that, looks
> fine to me.
Will add, thanks
--
Pavel Begunkov
next prev parent reply other threads:[~2021-10-21 8:42 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-20 20:03 [PATCH 0/2] optimise blk_try_enter_queue() Pavel Begunkov
2021-10-20 20:03 ` [PATCH 1/2] percpu_ref: percpu_ref_tryget_live() version holding RCU Pavel Begunkov
2021-10-20 20:10 ` Tejun Heo
2021-10-21 8:41 ` Pavel Begunkov [this message]
2021-10-20 20:03 ` [PATCH 2/2] block: kill extra rcu lock/unlock in queue enter Pavel Begunkov
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=e7319f50-999b-2540-62f1-201afcb29bf3@gmail.com \
--to=asml.silence@gmail.com \
--cc=axboe@kernel.dk \
--cc=cl@linux.com \
--cc=dennis@kernel.org \
--cc=linux-block@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=tj@kernel.org \
/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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.