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Petersen" , Jens Axboe , Keith Busch , Bart Van Assche , Christoph Hellwig , James Bottomley , Jaegeuk Kim , alim.akhtar@samsung.com, avri.altman@wdc.com, linux-scsi@vger.kernel.org, linux-block@vger.kernel.org Subject: Re: [PATCH] scsi: ufs: mark HPB support as BROKEN From: "Martin K. 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This approach takes a bit effort, but avoids tags > reservation. Yep, I was just noting that error handling was a better example than the ioctl given the context. > 1) how many queue depth for the hba? If it is small, even 1 reservation > can affect performance. Indeed. But there is no free lunch. > 2) how many inflight write buffer commands are to be supported? Or how > many is enough for obtaining expected performance? If the number is > big, reserved tags can't work. That really is something the UFS developers need to work out. I am not sure whether permanently pinning down memory is a bigger problem than queue tags being a finite resource. -- Martin K. Petersen Oracle Linux Engineering