From: Christoph Hellwig <hch@lst.de>
To: John Garry <john.garry@huawei.com>
Cc: Ming Lei <ming.lei@redhat.com>,
James Bottomley <James.Bottomley@HansenPartnership.com>,
linux-scsi@vger.kernel.org,
"Martin K . Petersen" <martin.petersen@oracle.com>,
Sumanesh Samanta <sumanesh.samanta@broadcom.com>,
"Ewan D . Milne" <emilne@redhat.com>,
Hannes Reinecke <hare@suse.de>,
Bart Van Assche <bart.vanassche@wdc.com>,
Christoph Hellwig <hch@lst.de>
Subject: Re: [PATCH] scsi: avoid to fetch scsi host template instance in IO path
Date: Mon, 2 Mar 2020 14:15:41 +0100 [thread overview]
Message-ID: <20200302131541.GA13265@lst.de> (raw)
In-Reply-To: <f23daab7-7aa0-1c34-8137-7abead09016c@huawei.com>
On Mon, Mar 02, 2020 at 10:58:55AM +0000, John Garry wrote:
> On 28/02/2020 09:33, Ming Lei wrote:
>> scsi host template struct is quite big, and the following three
>> fields are needed in SCSI IO path:
>>
>> - queuecommand
>> - commit_rqs
>> - cmd_size
>
> Would it have been nearly as good to reorganise Scsi host template
> structure to ensure that these are adjacent?
>
> I say nearly, as it avoids the shost->hostt read.
That would be worth trying. Replicating function pointers out of
read-only data structures generally isn't a very good idea.
next prev parent reply other threads:[~2020-03-02 13:15 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-28 9:33 [PATCH] scsi: avoid to fetch scsi host template instance in IO path Ming Lei
2020-03-02 4:32 ` Bart Van Assche
2020-03-02 10:58 ` John Garry
2020-03-02 13:15 ` Christoph Hellwig [this message]
2020-03-02 22:30 ` Ming Lei
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