From: Chaitanya Kulkarni <chaitanyak@nvidia.com>
To: brookxu.cn <brookxu.cn@gmail.com>,
"kbusch@kernel.org" <kbusch@kernel.org>,
"axboe@kernel.dk" <axboe@kernel.dk>, "hch@lst.de" <hch@lst.de>,
"sagi@grimberg.me" <sagi@grimberg.me>
Cc: "linux-nvme@lists.infradead.org" <linux-nvme@lists.infradead.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] nvme-fabrics: use reserved tag for reg read/write command
Date: Tue, 30 Apr 2024 17:42:16 +0000 [thread overview]
Message-ID: <06b57f1e-d412-454b-a708-521427384531@nvidia.com> (raw)
In-Reply-To: <20240430021753.385089-1-brookxu.cn@gmail.com>
On 4/29/24 19:17, brookxu.cn wrote:
> From: Chunguang Xu <chunguang.xu@shopee.com>
>
> In some scenarios, if too many commands are issued by nvme command in
> the same time by user tasks, this may exhaust all tags of admin_q. If
> a reset (nvme reset or IO timeout) occurs before these commands finish,
> reconnect routine may fail to update nvme regs due to insufficient tags,
> which will cause kernel hang forever. In order to workaround this issue,
> maybe we can let reg_read32()/reg_read64()/reg_write32() use reserved
> tags. This maybe safe for nvmf:
>
> 1. For the disable ctrl path, we will not issue connect command
> 2. For the enable ctrl / fw activate path, since connect and reg_xx()
> are called serially.
>
> So the reserved tags may still be enough while reg_xx() use reserved tags.
>
> Signed-off-by: Chunguang Xu <chunguang.xu@shopee.com>
> ---
>
Looks good.
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
-ck
prev parent reply other threads:[~2024-04-30 17:42 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-30 2:17 [PATCH] nvme-fabrics: use reserved tag for reg read/write command brookxu.cn
2024-04-30 3:46 ` Chaitanya Kulkarni
2024-04-30 5:10 ` 许春光
2024-04-30 6:59 ` Chaitanya Kulkarni
2024-04-30 8:59 ` 许春光
2024-04-30 9:44 ` Sagi Grimberg
2024-04-30 17:42 ` Chaitanya Kulkarni [this message]
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