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Subject: Re: [PATCH for-next 00/32] spin lock usage optimization for SCSI
 drivers
To:     Finn Thain <fthain@telegraphics.com.au>
References: <1612697823-8073-1-git-send-email-tanxiaofei@huawei.com>
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CC:     <jejb@linux.ibm.com>, <martin.petersen@oracle.com>,
        <linux-scsi@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        <linuxarm@openeuler.org>
From:   tanxiaofei <tanxiaofei@huawei.com>
Message-ID: <a555f4b2-4df9-7bf4-e76c-3556d5ccb4ff@huawei.com>
Date:   Tue, 9 Feb 2021 10:00:22 +0800
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Hi Finn,
Thanks for reviewing the patch set.

On 2021/2/8 15:57, Finn Thain wrote:
> On Sun, 7 Feb 2021, Xiaofei Tan wrote:
>
>> Replace spin_lock_irqsave with spin_lock in hard IRQ of SCSI drivers.
>> There are no function changes, but may speed up if interrupt happen too
>> often.
>
> This change doesn't necessarily work on platforms that support nested
> interrupts.
>

Linux doesn't support nested interrupts anymore after the following 
patch, so please don't worry this.

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=e58aa3d2d0cc

> Were you able to measure any benefit from this change on some other
> platform?
>

It's hard to measure the benefit of this change. Hmm, you could take 
this patch set as cleanup. thanks.

> Please see also,
> https://lore.kernel.org/linux-scsi/89c5cb05cb844939ae684db0077f675f@h3c.com/
>
> .
>