From: Jens Axboe <axboe@kernel.dk>
To: JackieLiu <liuyun01@kylinos.cn>
Cc: linux-block@vger.kernel.org
Subject: Re: replace sq_mask with ring_mask
Date: Thu, 16 May 2019 08:50:33 -0600 [thread overview]
Message-ID: <eea42825-8186-ab15-3bcc-4b05cbe33409@kernel.dk> (raw)
In-Reply-To: <820102D0-D768-4E39-A9FE-FB75A53FEE8F@kylinos.cn>
On 5/15/19 12:47 AM, JackieLiu wrote:
> Hello Jens Axboe
>
> Could we replace ctx->sq_mask/ctx->cq_mask with cq_ring->ring_mask
> /sq_ring->ring_mask ? because it’s a constant and never change in
> io_uring.c
>
> I found that ctx->sq_mask just used on
>
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/fs/io_uring.c?h=v5.1#n1831
>
> and we can replace like follow:
>
> - head = READ_ONCE(ring->array[head & ctx->sq_mask]);
> + head = READ_ONCE(ring->array[head & ring->ring_mask]);
>
> If I understand incorrectly, please point out.
We could, but we cache it in the kernel since the ring value could
potentially be modified by the application.
--
Jens Axboe
prev parent reply other threads:[~2019-05-16 14:50 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-15 6:47 replace sq_mask with ring_mask JackieLiu
2019-05-16 14:50 ` Jens Axboe [this message]
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