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From: Bart Van Assche <bvanassche@acm.org>
To: Yang Yang <yang.yang@vivo.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Jens Axboe <axboe@kernel.dk>, Ming Lei <ming.lei@redhat.com>,
	Omar Sandoval <osandov@fb.com>,
	linux-kernel@vger.kernel.org, linux-block@vger.kernel.org
Subject: Re: [PATCH v6] sbitmap: fix io hung due to race on sbitmap_word::cleared
Date: Wed, 10 Jul 2024 12:54:01 -0700	[thread overview]
Message-ID: <29e50fff-fa7f-4b92-bfe9-7665c934b7dc@acm.org> (raw)
In-Reply-To: <20240710065616.1060803-1-yang.yang@vivo.com>

On 7/9/24 11:56 PM, Yang Yang wrote:
> +	/**
> +	 * @swap_lock: Held while swapping word <-> cleared
> +	 */
> +	spinlock_t swap_lock;

Why is only swapping 'word' with 'cleared' protected by the spinlock?
If all 'cleared' changes would be protected by this spinlock then
that would allow to eliminate the expensive xchg() call from
sbitmap_deferred_clear().

Thanks,

Bart.

  parent reply	other threads:[~2024-07-10 19:54 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-07-10  6:56 Yang Yang
2024-07-10 16:41 ` Bart Van Assche
2024-07-11  9:47   ` YangYang
2024-07-10 19:54 ` Bart Van Assche [this message]
2024-07-11 12:48   ` YangYang
2024-07-11 13:39     ` Ming Lei
2024-07-11 16:33       ` Bart Van Assche
2024-07-12  1:01         ` Ming Lei
2024-07-12 17:53           ` Bart Van Assche

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