From: Heiner Kallweit <hkallweit1@gmail.com>
To: Chaitanya Kulkarni <Chaitanya.Kulkarni@wdc.com>
Cc: Jens Axboe <axboe@kernel.dk>,
"kbusch@kernel.org" <kbusch@kernel.org>,
"hch@lst.de" <hch@lst.de>,
"linux-nvme@lists.infradead.org" <linux-nvme@lists.infradead.org>,
"sagi@grimberg.me" <sagi@grimberg.me>
Subject: Re: [PATCH 1/2] nvme-pci; remove the barriers nvme_irq()
Date: Tue, 23 Feb 2021 15:36:22 +0100 [thread overview]
Message-ID: <f2d9cd44-8f24-a4ee-ca26-a1d2b8c74c3d@gmail.com> (raw)
In-Reply-To: <BYAPR04MB496513669571FA6541E58B8686809@BYAPR04MB4965.namprd04.prod.outlook.com>
On 23.02.2021 07:54, Chaitanya Kulkarni wrote:
> (+Heiner)
>
> On 2/19/21 05:40, Jens Axboe wrote:
>> On 2/18/21 11:37 PM, Chaitanya Kulkarni wrote:
>>> The barriers were added to the nvme_irq() in the
>>> commit 3a7afd8ee42a ("nvme-pci: remove the CQ lock for interrupt driven queues")
>>> to prevent compiler from doing memory optimization for the variabes that
>>> were protected previously by spinlock in nvme_irq() at completion queue
>>> processing and with queue head check condition..
>>>
>>> The variable nvmeq->last_cq_head from those checks was removed in the
>>> commit f6c4d97b0d82 ("nvme/pci: Remove last_cq_head")") that was
>>> preventing poll queues from mistakenly triggering the spurious
>>> interrupt detection.
>>>
>>> Remove the barriers which were protecting the updates to the variables.
>> Would seem prudent to just ask the original submitter to send a v2
>> of his patch, as that's where it came from.
>>
> Please let me know if you want to send V2 otherwise please ack this series.
>
Fine with me if you send the patch. You could just add a Reported-by
Reviewed-by: Heiner Kallweit <hkallweit1@gmail.com>
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next prev parent reply other threads:[~2021-02-23 14:36 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-19 6:37 [PATCH 1/2] nvme-pci; remove the barriers nvme_irq() Chaitanya Kulkarni
2021-02-19 13:40 ` Jens Axboe
2021-02-23 6:54 ` Chaitanya Kulkarni
2021-02-23 14:36 ` Heiner Kallweit [this message]
2021-02-23 20:49 ` Chaitanya Kulkarni
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