From: John Garry <john.g.garry@oracle.com>
To: Jerry Snitselaar <jsnitsel@redhat.com>, Joerg Roedel <joro@8bytes.org>
Cc: Vasant Hegde <vasant.hegde@amd.com>,
Peng Zhang <zhangpeng.00@bytedance.com>,
Robin Murphy <robin.murphy@arm.com>,
will@kernel.org, iommu@lists.linux.dev,
linux-kernel@vger.kernel.org, Li Bin <huawei.libin@huawei.com>,
Xie XiuQi <xiexiuqi@huawei.com>,
Yang Yingliang <yangyingliang@huawei.com>,
Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Subject: Re: [PATCH] iommu: Avoid softlockup and rcu stall in fq_flush_timeout().
Date: Mon, 22 May 2023 16:35:34 +0100 [thread overview]
Message-ID: <57017dea-c453-82bc-18b1-79663e77552d@oracle.com> (raw)
In-Reply-To: <vxxh3laqaavyxx3f2c65k7zui6wkahm6fspy6hvwpofsxtialo@ne7za5hvlgk2>
On 22/05/2023 16:18, Jerry Snitselaar wrote:
>> My guess is that the allocations are too big and not covered by the
>> allocation sizes supported by the flush-queue code. But maybe this is
>> something that can be fixed. Or the flush-queue code could even be
>> changed to auto-adapt to allocation patterns of the device driver?
>>
>> Regards,
>>
>> Joerg
> In the case I know of it involved some proprietary test suites
> (Hazard I/O, and Medusa?), and the lpfc driver. I was able to force
> the condition using fio with a number of jobs running. I'll play
> around and see if I can figure out a point where it starts to become
> an issue.
>
> I mentioned what the nvme driver did to the Broadcom folks for the max
> dma size, but I haven't had a chance to go looking at it myself yet to
> see if there is somewhere in the lpfc code to fix up.
JFYI, SCSI core already supports setting this in shost->opt_sectors, see
example in sas_host_setup().
This issue may continue to pop up so we may need a better way to turn it
on/off for all drivers or classes of drivers.
John
prev parent reply other threads:[~2023-05-22 15:36 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-16 7:11 [PATCH] iommu: Avoid softlockup and rcu stall in fq_flush_timeout() Peng Zhang
2023-02-16 8:49 ` Hillf Danton
2023-02-16 11:02 ` Peng Zhang
2023-02-16 11:44 ` Hillf Danton
2023-04-10 22:22 ` Jerry Snitselaar
2023-04-18 10:41 ` Vasant Hegde
2023-04-28 5:44 ` Vasant Hegde
2023-05-22 14:58 ` Joerg Roedel
2023-05-22 15:18 ` Jerry Snitselaar
2023-05-22 15:35 ` John Garry [this message]
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