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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: 47652159-7683-4da4-b657-08d5f89aa16c X-MS-Exchange-CrossTenant-originalarrivaltime: 02 Aug 2018 17:08:55.7670 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: b61c8803-16f3-4c35-9b17-6f65f441df86 X-MS-Exchange-Transport-CrossTenantHeadersStamped: MWHPR04MB0752 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 2018-08-03 at 00:58 +-0800, Ming Lei wrote: +AD4- And about the situations you mentioned, no any special as normal case= s +AD4- or thousands of LUNs. Just a batch of queues are waken up from one +AD4- single wait queue(sbq+AF8-wait+AF8-state), and inside each wait queue= , queues +AD4- are handled actually in FIFO order. +AD4-=20 +AD4- Or what is your expected ideal behaviour about fairness? Hello Ming, What I expect is if the number of LUNs is really large that all LUNs are tr= eated equally. Unless someone can set up a test that demonstrates that this is st= ill the case for commit 97889f9ac24f (+ACI-blk-mq: remove synchronize+AF8-rcu()= from blk+AF8-mq+AF8-del+AF8-queue+AF8-tag+AF8-set()+ACI-), I will assume that th= at commit breaks fairness. Bart.