From: Jens Axboe <[email protected]>
To: Pavel Begunkov <[email protected]>,
[email protected], [email protected],
Tejun Heo <[email protected]>
Subject: Re: [PATCH 1/2] pcpu_ref: add percpu_ref_tryget_many()
Date: Tue, 17 Dec 2019 16:42:59 -0700 [thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <c430d1a603f9ffe01661fc1b3bad6e3101a8b855.1576621553.git.asml.silence@gmail.com>
CC Tejun on this one. Looks fine to me, and matches the put path.
On 12/17/19 3:28 PM, Pavel Begunkov wrote:
> Add percpu_ref_tryget_many(), which works the same way as
> percpu_ref_tryget(), but grabs specified number of refs.
>
> Signed-off-by: Pavel Begunkov <[email protected]>
> ---
> include/linux/percpu-refcount.h | 24 ++++++++++++++++++++----
> 1 file changed, 20 insertions(+), 4 deletions(-)
>
> diff --git a/include/linux/percpu-refcount.h b/include/linux/percpu-refcount.h
> index 390031e816dc..19079b62ce31 100644
> --- a/include/linux/percpu-refcount.h
> +++ b/include/linux/percpu-refcount.h
> @@ -210,15 +210,17 @@ static inline void percpu_ref_get(struct percpu_ref *ref)
> }
>
> /**
> - * percpu_ref_tryget - try to increment a percpu refcount
> + * percpu_ref_tryget_many - try to increment a percpu refcount
> * @ref: percpu_ref to try-get
> + * @nr: number of references to get
> *
> * Increment a percpu refcount unless its count already reached zero.
> * Returns %true on success; %false on failure.
> *
> * This function is safe to call as long as @ref is between init and exit.
> */
> -static inline bool percpu_ref_tryget(struct percpu_ref *ref)
> +static inline bool percpu_ref_tryget_many(struct percpu_ref *ref,
> + unsigned long nr)
> {
> unsigned long __percpu *percpu_count;
> bool ret;
> @@ -226,10 +228,10 @@ static inline bool percpu_ref_tryget(struct percpu_ref *ref)
> rcu_read_lock();
>
> if (__ref_is_percpu(ref, &percpu_count)) {
> - this_cpu_inc(*percpu_count);
> + this_cpu_add(*percpu_count, nr);
> ret = true;
> } else {
> - ret = atomic_long_inc_not_zero(&ref->count);
> + ret = atomic_long_add_unless(&ref->count, nr, 0);
> }
>
> rcu_read_unlock();
> @@ -237,6 +239,20 @@ static inline bool percpu_ref_tryget(struct percpu_ref *ref)
> return ret;
> }
>
> +/**
> + * percpu_ref_tryget - try to increment a percpu refcount
> + * @ref: percpu_ref to try-get
> + *
> + * Increment a percpu refcount unless its count already reached zero.
> + * Returns %true on success; %false on failure.
> + *
> + * This function is safe to call as long as @ref is between init and exit.
> + */
> +static inline bool percpu_ref_tryget(struct percpu_ref *ref)
> +{
> + return percpu_ref_tryget_many(ref, 1);
> +}
> +
> /**
> * percpu_ref_tryget_live - try to increment a live percpu refcount
> * @ref: percpu_ref to try-get
>
--
Jens Axboe
next prev parent reply other threads:[~2019-12-17 23:43 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-17 22:28 [PATCH 0/2] optimise ctx's refs grabbing in io_uring Pavel Begunkov
2019-12-17 22:28 ` [PATCH 1/2] pcpu_ref: add percpu_ref_tryget_many() Pavel Begunkov
2019-12-17 23:42 ` Jens Axboe [this message]
2019-12-18 16:26 ` Tejun Heo
2019-12-18 17:49 ` Dennis Zhou
2019-12-21 15:36 ` Pavel Begunkov
2019-12-17 22:28 ` [PATCH 2/2] io_uring: batch getting pcpu references Pavel Begunkov
2019-12-17 23:21 ` Jens Axboe
2019-12-17 23:31 ` Jens Axboe
2019-12-18 9:25 ` Pavel Begunkov
2019-12-18 9:23 ` Pavel Begunkov
2019-12-18 0:02 ` Jens Axboe
2019-12-18 10:41 ` Pavel Begunkov
2019-12-21 16:15 ` [PATCH v2 0/3] optimise ctx's refs grabbing in io_uring Pavel Begunkov
2019-12-21 16:15 ` [PATCH v2 1/3] pcpu_ref: add percpu_ref_tryget_many() Pavel Begunkov
2019-12-21 16:15 ` [PATCH v2 2/3] io_uring: batch getting pcpu references Pavel Begunkov
2019-12-21 16:15 ` [PATCH RFC v2 3/3] io_uring: batch get(ctx->ref) across submits Pavel Begunkov
2019-12-21 16:20 ` Pavel Begunkov
2019-12-21 16:38 ` Jens Axboe
2019-12-21 16:48 ` Pavel Begunkov
2019-12-21 17:01 ` Jens Axboe
2019-12-21 17:26 ` Pavel Begunkov
2019-12-21 20:12 ` [PATCH v3 0/2] optimise ctx's refs grabbing in io_uring Pavel Begunkov
2019-12-21 20:12 ` [PATCH v3 1/2] pcpu_ref: add percpu_ref_tryget_many() Pavel Begunkov
2019-12-21 20:12 ` [PATCH v3 2/2] io_uring: batch getting pcpu references Pavel Begunkov
2019-12-21 21:56 ` Pavel Begunkov
2019-12-28 11:13 ` [PATCH v4 0/2] optimise ctx's refs grabbing in io_uring Pavel Begunkov
2019-12-28 11:13 ` [PATCH v4 1/2] pcpu_ref: add percpu_ref_tryget_many() Pavel Begunkov
2019-12-28 11:13 ` [PATCH v4 2/2] io_uring: batch getting pcpu references Pavel Begunkov
2019-12-28 11:15 ` Pavel Begunkov
2019-12-28 17:03 ` Jens Axboe
2019-12-28 18:37 ` Pavel Begunkov
2019-12-30 3:33 ` Brian Gianforcaro
2019-12-30 18:45 ` Pavel Begunkov
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