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charset="utf-7" Content-ID: Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-OriginatorOrg: wdc.com X-MS-Exchange-CrossTenant-Network-Message-Id: a316d69a-5ec6-4a47-c287-08d5f88fe263 X-MS-Exchange-CrossTenant-originalarrivaltime: 02 Aug 2018 15:52:00.3899 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: b61c8803-16f3-4c35-9b17-6f65f441df86 X-MS-Exchange-Transport-CrossTenantHeadersStamped: MWHPR04MB0622 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2018-08-01 at 16:58 +-0800, Ming Lei wrote: +AD4- On Wed, Aug 01, 2018 at 10:17:30AM +-0800, jianchao.wang wrote: +AD4- +AD4- However, due to the limits in hctx+AF8-may+AF8-queue, q+AF8-b s= till cannot get the +AD4- +AD4- tags. The RR restart also will not wake up q+AF8-a. +AD4- +AD4- This is unfair for q+AF8-a. +AD4- +AD4-=20 +AD4- +AD4- When we remove RR restart fashion, at least, the q+AF8-a will b= e waked up by +AD4- +AD4- the hctx restart. +AD4- +AD4- Is this the improvement of fairness you said in driver tag allo= cation ? +AD4-=20 +AD4- I mean the fairness is totally covered by the general tag allocation +AD4- algorithm now, which is sort of FIFO style because of waitqueue, but = RR +AD4- restart wakes up queue in the order of request queue. From sbitmap.h: +ACM-define SBQ+AF8-WAIT+AF8-QUEUES 8 What do you think is the effect of your patch if more than eight LUNs are active and the SCSI queue is full? Thanks, Bart.