From: Hannes Reinecke <hare@suse.de>
To: Jason Yan <yanaijie@huawei.com>,
martin.petersen@oracle.com, jejb@linux.vnet.ibm.com
Cc: linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org,
john.garry@huawei.com, zhaohongjiang@huawei.com, hare@suse.com,
dan.j.williams@intel.com, jthumshirn@suse.de,
Raj.Dinesh@microsemi.com, hch@lst.de, huangdaode@hisilicon.com,
chenxiang66@hisilicon.com, xiyou.wangcong@gmail.com,
Ewan Milne <emilne@redhat.com>, Tomas Henzl <thenzl@redhat.com>
Subject: Re: [PATCH v5 2/7] scsi: libsas: shut down the PHY if events reached the threshold
Date: Mon, 8 Jan 2018 08:38:39 +0100 [thread overview]
Message-ID: <6ef7025e-f330-ede4-d194-096efd5d7c56@suse.de> (raw)
In-Reply-To: <c1accdc7-00a7-06a3-5531-ae64ef797cd2@suse.de>
On 12/15/2017 01:18 PM, Hannes Reinecke wrote:
> On 12/08/2017 10:42 AM, Jason Yan wrote:
>> If the PHY burst too many events, we will alloc a lot of events for the
>> worker. This may leads to memory exhaustion.
>>
>> Dan Williams suggested to shut down the PHY if the events reached the
>> threshold, because in this case the PHY may have gone into some
>> erroneous state. Users can re-enable the PHY by sysfs if they want.
>>
>> We cannot use the fixed memory pool because if we run out of events, the
>> shut down event and loss of signal event will lost too. The events still
>> need to be allocated and processed in this case.
>>
>> Suggested-by: Dan Williams <dan.j.williams@intel.com>
>> Signed-off-by: Jason Yan <yanaijie@huawei.com>
>> CC: John Garry <john.garry@huawei.com>
>> CC: Johannes Thumshirn <jthumshirn@suse.de>
>> CC: Ewan Milne <emilne@redhat.com>
>> CC: Christoph Hellwig <hch@lst.de>
>> CC: Tomas Henzl <thenzl@redhat.com>
>> ---
>> drivers/scsi/libsas/sas_init.c | 33 ++++++++++++++++++++++++++++++++-
>> drivers/scsi/libsas/sas_phy.c | 27 ++++++++++++++++++++++++++-
>> include/scsi/libsas.h | 6 ++++++
>> 3 files changed, 64 insertions(+), 2 deletions(-)
>>
> Well, this still looks a bit error prone; what if the system runs out of
> memory before the pool is exhausted?
> (Also a threshold of 1024 events is a bit arbitrary; one might want to
> adjust that).
>
> Couldn't you allocate two static events always (for shutdown and signal
> loss), and then use a fixed pool?
>
Has actually been resolved by the next patch.
Reviewed-by: Hannes Reinecke <hare@suse.com>
Cheers,
Hannes
--
Dr. Hannes Reinecke Teamlead Storage & Networking
hare@suse.de +49 911 74053 688
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: F. Imendörffer, J. Smithard, J. Guild, D. Upmanyu, G. Norton
HRB 21284 (AG Nürnberg)
next prev parent reply other threads:[~2018-01-08 7:38 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-12-08 9:42 [PATCH v5 0/7] Enhance libsas hotplug feature Jason Yan
2017-12-08 9:42 ` Jason Yan
2017-12-08 9:42 ` [PATCH v5 1/7] scsi: libsas: Use dynamic alloced work to avoid sas event lost Jason Yan
2017-12-08 9:42 ` Jason Yan
2017-12-15 12:14 ` Hannes Reinecke
2017-12-08 9:42 ` [PATCH v5 2/7] scsi: libsas: shut down the PHY if events reached the threshold Jason Yan
2017-12-08 9:42 ` Jason Yan
2017-12-15 12:18 ` Hannes Reinecke
2018-01-08 7:38 ` Hannes Reinecke [this message]
2017-12-08 9:42 ` [PATCH v5 3/7] scsi: libsas: make the event threshold configurable Jason Yan
2017-12-08 9:42 ` Jason Yan
2017-12-08 12:09 ` John Garry
2017-12-08 12:09 ` John Garry
2017-12-15 12:19 ` Hannes Reinecke
2018-01-04 10:04 ` John Garry
2018-01-04 10:04 ` John Garry
2017-12-08 9:42 ` [PATCH v5 4/7] scsi: libsas: Use new workqueue to run sas event and disco event Jason Yan
2017-12-08 9:42 ` Jason Yan
2017-12-15 12:20 ` Hannes Reinecke
2017-12-08 9:42 ` [PATCH v5 5/7] scsi: libsas: use flush_workqueue to process disco events synchronously Jason Yan
2017-12-08 9:42 ` Jason Yan
2017-12-15 12:21 ` Hannes Reinecke
2017-12-08 9:42 ` [PATCH v5 6/7] scsi: libsas: direct call probe and destruct Jason Yan
2017-12-08 9:42 ` Jason Yan
2017-12-15 12:23 ` Hannes Reinecke
2017-12-08 9:42 ` [PATCH v5 7/7] scsi: libsas: notify event PORTE_BROADCAST_RCVD in sas_enable_revalidation() Jason Yan
2017-12-08 9:42 ` Jason Yan
2017-12-15 12:26 ` Hannes Reinecke
2018-01-02 11:06 ` [PATCH v5 0/7] Enhance libsas hotplug feature John Garry
2018-01-02 11:06 ` John Garry
2018-01-04 6:01 ` Martin K. Petersen
2018-01-04 6:01 ` Martin K. Petersen
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