From: John Garry <john.g.garry@oracle.com>
To: Bart Van Assche <bvanassche@acm.org>,
"Martin K . Petersen" <martin.petersen@oracle.com>
Cc: linux-scsi@vger.kernel.org, linux-block@vger.kernel.org,
Jens Axboe <axboe@kernel.dk>,
Christoph Hellwig <hch@infradead.org>,
Ming Lei <ming.lei@redhat.com>,
"James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Subject: Re: [PATCH 3/3] scsi: core: Improve IOPS in case of host-wide tags
Date: Fri, 12 Sep 2025 15:37:58 +0100 [thread overview]
Message-ID: <e10e9387-c8ad-4bb5-80fb-42bbafdb9243@oracle.com> (raw)
In-Reply-To: <0c056e23-59c7-4125-8cd6-1e22ceaadea4@acm.org>
On 11/09/2025 18:37, Bart Van Assche wrote:
> On 9/11/25 1:15 AM, John Garry wrote:
>> this can race with a call to scsi_change_queue_depth() (which may free
>> sdev->budget_map.map), right?
>>
>> scsi_change_queue_depth() does not seem to do any queue freezing.
>
> Hi John,
>
It was not specifically freezing which I was concerned with. It was how
with the freeing of the sbitmap now looks racy. Just resizing the
sbitmap would not have such issues. I mentioned queue freezing as queue
freezing was introduced in scsi_realloc_sdev_budget_map() for freeing
the queue - I'm not sure why, though.
> Are there any SCSI devices left about which we care and for which queue
> depth tracking is important?
many drivers still set .track_queue_depth
prev parent reply other threads:[~2025-09-12 14:38 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-09-10 21:32 [PATCH 0/3] Improve host-wide tag IOPS Bart Van Assche
2025-09-10 21:32 ` [PATCH 1/3] block: Export blk_mq_all_tag_iter() Bart Van Assche
2025-09-11 8:32 ` Ming Lei
2025-09-11 16:49 ` Bart Van Assche
2025-09-10 21:32 ` [PATCH 2/3] ufs: core: Use scsi_device_busy() Bart Van Assche
2025-09-11 9:18 ` Peter Wang (王信友)
2025-09-10 21:32 ` [PATCH 3/3] scsi: core: Improve IOPS in case of host-wide tags Bart Van Assche
2025-09-11 6:40 ` Hannes Reinecke
2025-09-11 15:45 ` Bart Van Assche
2025-09-11 8:15 ` John Garry
2025-09-11 15:59 ` Bart Van Assche
2025-09-11 17:37 ` Bart Van Assche
2025-09-12 14:37 ` John Garry [this message]
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