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From: Guoqing Jiang <guoqing.jiang@linux.dev>
To: Yu Kuai <yukuai1@huaweicloud.com>, song@kernel.org
Cc: linux-raid@vger.kernel.org, linux-kernel@vger.kernel.org,
	yukuai3@huawei.com, yi.zhang@huawei.com
Subject: Re: [PATCH -next 2/3] md/raid10: convert resync_lock to use seqlock
Date: Fri, 2 Sep 2022 17:42:42 +0800	[thread overview]
Message-ID: <3d8859bc-80d6-08b0-fd40-8874df4d3419@linux.dev> (raw)
In-Reply-To: <20220829131502.165356-3-yukuai1@huaweicloud.com>

Hi,

On 8/29/22 9:15 PM, Yu Kuai wrote:
> +static bool wait_barrier_nolock(struct r10conf *conf)
> +{
> +	unsigned int seq = raw_read_seqcount(&conf->resync_lock.seqcount);
> +
> +	if (seq & 1)
> +		return false;
> +
> +	if (READ_ONCE(conf->barrier))
> +		return false;
> +
> +	atomic_inc(&conf->nr_pending);
> +	if (!read_seqcount_retry(&conf->resync_lock.seqcount, seq))

I think 'seq' is usually get from read_seqcount_begin.

> +		return true;
> +
> +	atomic_dec(&conf->nr_pending);
> +	return false;
> +

Thanks,
Guoqing

  parent reply	other threads:[~2022-09-02  9:42 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-08-29 13:14 [PATCH -next 0/3] md/raid10: reduce lock contention for io Yu Kuai
2022-08-29 13:15 ` [PATCH -next 1/3] md/raid10: fix improper BUG_ON() in raise_barrier() Yu Kuai
2022-08-29 19:53   ` John Stoffel
2022-08-30  1:01     ` Yu Kuai
2022-08-30  6:32     ` Paul Menzel
2022-08-29 13:15 ` [PATCH -next 2/3] md/raid10: convert resync_lock to use seqlock Yu Kuai
2022-09-01 18:41   ` Logan Gunthorpe
2022-09-02  0:49     ` Guoqing Jiang
2022-09-02  0:56       ` Logan Gunthorpe
2022-09-02  1:00         ` Guoqing Jiang
2022-09-02  1:21     ` Yu Kuai
2022-09-02  8:14       ` Yu Kuai
2022-09-02 17:03         ` Logan Gunthorpe
2022-09-03  6:07           ` Yu Kuai
2022-09-02  9:42   ` Guoqing Jiang [this message]
2022-09-02 10:02     ` Yu Kuai
2022-09-02 10:16       ` Guoqing Jiang
2022-09-02 10:53         ` Yu Kuai
2022-08-29 13:15 ` [PATCH -next 3/3] md/raid10: prevent unnecessary calls to wake_up() in fast path Yu Kuai
2022-08-29 13:40 ` [PATCH -next 0/3] md/raid10: reduce lock contention for io Guoqing Jiang
2022-08-31 11:55   ` Yu Kuai
2022-08-29 13:58 ` Paul Menzel
2022-08-30  1:09   ` Yu Kuai
2022-08-31 11:59     ` Paul Menzel
2022-08-31 12:07       ` Yu Kuai
2022-08-31 18:00 ` Song Liu
2022-09-03  6:08   ` Yu Kuai
2022-09-09 14:45     ` Song Liu

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