From: John Garry <john.garry@huawei.com>
To: wangyijing <wangyijing@huawei.com>,
Dan Williams <dan.j.williams@intel.com>
Cc: "James E.J. Bottomley" <jejb@linux.vnet.ibm.com>,
"Martin K. Petersen" <martin.petersen@oracle.com>,
<chenqilin2@huawei.com>, <hare@suse.com>,
linux-scsi <linux-scsi@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
<chenxiang66@hisilicon.com>, <huangdaode@hisilicon.com>,
<wangkefeng.wang@huawei.com>, <zhaohongjiang@huawei.com>,
<dingtianhong@huawei.com>, <guohanjun@huawei.com>,
Wei Fang <fangwei1@huawei.com>, <yanaijie@huawei.com>,
Christoph Hellwig <hch@lst.de>, Yousong He <heyousong@huawei.com>,
Linuxarm <linuxarm@huawei.com>
Subject: Re: [PATCH 1/2] libsas: Don't process sas events in static works
Date: Mon, 22 May 2017 10:28:01 +0100 [thread overview]
Message-ID: <392354c0-a4a1-99a8-7723-25513efb835c@huawei.com> (raw)
In-Reply-To: <59227D16.6000102@huawei.com>
On 22/05/2017 06:54, wangyijing wrote:
>> I also think for safety this should use a mempool that guarantees that
>> > events can continue to be processed under system memory pressure.
> What I am worried about is it's would still fail if the mempool is used empty during memory pressure.
>
>> > Also, have you considered the case when a broken phy starts throwing a
>> > constant stream of events? Is there a point at which libsas should
>> > stop queuing events and disable the phy?
> Not yet, I didn't find this issue in real case, but I agree, it's really a problem in some broken
> hardware, I think it's not a easy problem, we could improve it step by step.
>
> Thanks!
> Yijing.
>
I have seen this scenario on our development board when we have a bad
physical cable connection - the PHY continually goes up and down in a loop.
So, in this regard, it is worth safeguarding against this scenario.
John
next prev parent reply other threads:[~2017-05-22 9:28 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-05-20 6:39 [PATCH 0/2] Enhance libsas hotplug feature Yijing Wang
2017-05-20 6:39 ` [PATCH 1/2] libsas: Don't process sas events in static works Yijing Wang
2017-05-21 3:44 ` Dan Williams
2017-05-22 5:54 ` wangyijing
2017-05-22 9:28 ` John Garry [this message]
2017-05-23 6:39 ` wangyijing
2017-05-20 6:39 ` [PATCH 2/2] libsas: Enhance libsas hotplug Yijing Wang
2017-05-25 9:04 ` John Garry
2017-05-25 12:31 ` wangyijing
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