From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Bart Van Assche To: "ming.lei@redhat.com" CC: "dm-devel@redhat.com" , "hch@infradead.org" , "linux-kernel@vger.kernel.org" , "linux-block@vger.kernel.org" , "osandov@fb.com" , "axboe@kernel.dk" , "snitzer@redhat.com" Subject: Re: [RFC PATCH] blk-mq: fixup RESTART when queue becomes idle Date: Fri, 19 Jan 2018 19:47:42 +0000 Message-ID: <1516391260.2968.27.camel@wdc.com> References: <20180118024124.8079-1-ming.lei@redhat.com> <20180118170353.GB19734@redhat.com> <1516296056.2676.23.camel@wdc.com> <20180118183039.GA20121@redhat.com> <1516301278.2676.35.camel@wdc.com> <20180119023212.GA25413@ming.t460p> <1516338585.4077.1.camel@wdc.com> <20180119073423.GC25369@ming.t460p> In-Reply-To: <20180119073423.GC25369@ming.t460p> Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 List-ID: T24gRnJpLCAyMDE4LTAxLTE5IGF0IDE1OjM0ICswODAwLCBNaW5nIExlaSB3cm90ZToNCj4gQ291 bGQgeW91IGV4cGxhaW4gYSBiaXQgd2hlbiBTQ1NJIHRhcmdldCByZXBsaWVzIHdpdGggQlVTWSB2 ZXJ5IG9mdGVuPw0KPiANCj4gSW5zaWRlIGluaXRpYXRvciwgd2UgaGF2ZSBsaW1pdGVkIHRoZSBt YXggcGVyLUxVTiByZXF1ZXN0cyBhbmQgcGVyLWhvc3QNCj4gcmVxdWVzdHMgYWxyZWFkeSBiZWZv cmUgY2FsbGluZyAucXVldWVfcnEoKS4NCg0KVGhhdCdzIGNvcnJlY3QuIEhvd2V2ZXIsIHdoZW4g YSBTQ1NJIGluaXRpYXRvciBhbmQgdGFyZ2V0IHN5c3RlbSBhcmUNCmNvbW11bmljYXRpbmcgd2l0 aCBlYWNoIG90aGVyIHRoZXJlIGlzIG5vIGd1YXJhbnRlZSB0aGF0IGluaXRpYXRvciBhbmQgdGFy Z2V0DQpxdWV1ZSBkZXB0aCBoYXZlIGJlZW4gdHVuZWQgcHJvcGVybHkuIElmIHRoZSBpbml0aWF0 b3IgcXVldWUgZGVwdGggYW5kIHRoZQ0KbnVtYmVyIG9mIHJlcXVlc3RzIHRoYXQgY2FuIGJlIGlu IGZsaWdodCBhY2NvcmRpbmcgdG8gdGhlIG5ldHdvcmsgcHJvdG9jb2wNCmFyZSBib3RoIGxhcmdl ciB0aGFuIHRoZSB0YXJnZXQgcXVldWUgZGVwdGggYW5kIGlmIHRoZSB0YXJnZXQgc3lzdGVtIHVz ZXMNCnJlbGF0aXZlbHkgc2xvdyBzdG9yYWdlIChlLmcuIGhhcmRkaXNrcykgdGhlbiBpdCBjYW4g aGFwcGVuIHRoYXQgdGhlIHRhcmdldA0KcmVwbGllcyB3aXRoIEJVU1kgb2Z0ZW4uDQoNClRoZSBM aW51eCBpU0NTSSBpbml0aWF0b3IgbGltaXRzIE1heE91dHN0YW5kaW5nUjJUICh0aGUgbnVtYmVy IG9mIHJlcXVlc3RzDQphbiBpbml0aWF0b3IgbWF5IHNlbnQgd2l0aG91dCBoYXZpbmcgcmVjZWl2 ZWQgYW4gYW5zd2VyIGZyb20gdGhlIHRhcmdldCkgdG8NCm9uZSBzbyBJIGRvbid0IHRoaW5rIHRo aXMgY2FuIGhhcHBlbiB3aGVuIHVzaW5nIGlTQ1NJL1RDUC4NCg0KV2l0aCB0aGUgU1JQIGluaXRp YXRvciBob3dldmVyIHRoZSBtYXhpbXVtIHJlcXVlc3RzIHRoYXQgY2FuIGJlIGluIGZsaWdodA0K YmV0d2VlbiBpbml0aWF0b3IgYW5kIHRhcmdldCBkZXBlbmRzIG9uIHRoZSBudW1iZXIgb2YgY3Jl ZGl0cyB0aGF0IHdlcmUNCm5lZ290aWF0ZWQgZHVyaW5nIGxvZ2luIGJldHdlZW4gaW5pdGlhdG9y IGFuZCB0YXJnZXQuIFNvbWUgdGltZSBhZ28gSSBtb2RpZmllZA0KdGhlIFNSUCBpbml0aWF0b3Ig c3VjaCB0aGF0IGl0IGxpbWl0cyB0aGUgaW5pdGlhdG9yIHF1ZXVlIGRlcHRoIHRvIHRoZSBudW1i ZXINCm9mIFNSUCBjcmVkaXRzIG1pbnVzIG9uZSAoZm9yIHRhc2sgbWFuYWdlbWVudCkuIFRoYXQg cmVzdWx0ZWQgaW4gYSBwZXJmb3JtYW5jZQ0KaW1wcm92ZW1lbnQgZHVlIHRvIGZld2VyIEJVU1kg Y29uZGl0aW9ucyBhdCB0aGUgaW5pdGlhdG9yIHNpZGUgKHNlZSBhbHNvIGNvbW1pdA0KN2FkZTQw MGFiYTlhICgiSUIvc3JwOiBSZWR1Y2UgbnVtYmVyIG9mIEJVU1kgY29uZGl0aW9ucyIpKS4gQW5v dGhlciBwYXRjaCBmb3INCnRoZSBTQ1NUIFNSUCB0YXJnZXQgZHJpdmVyIGxpbWl0ZWQgdGhlIG51 bWJlciBvZiBTUlAgY3JlZGl0cyB0byB0aGUgcXVldWUgZGVwdGgNCm9mIHRoZSBibG9jayBkZXZp Y2UgYXQgdGhlIHRhcmdldCBzaWRlLiBJJ20gcmVmZXJyaW5nIHRvIHRoZSBmb2xsb3dpbmcgY29k ZToNCmNoLT5ycV9zaXplID0gbWluKE1BWF9TUlBUX1JRX1NJWkUsIHNjc3RfZ2V0X21heF9sdW5f Y29tbWFuZHMoTlVMTCwgMCkpIChJIGhhdmUNCm5vdCB5ZXQgaGFkIHRoZSB0aW1lIHRvIHBvcnQg dGhpcyBjaGFuZ2UgdG8gTElPKS4NCg0KV2l0aG91dCBzdWNoIHR1bmluZyBhY3Jvc3MgaW5pdGlh dG9yIGFuZCB0YXJnZXQgaXQgY2FuIGhhcHBlbiBvZnRlbiB0aGF0IHRoZQ0KdGFyZ2V0IHN5c3Rl bSBzZW5kcyB0aGUgcmVwbHkgIkJVU1kiIGJhY2sgdG8gdGhlIGluaXRpYXRvci4gSSB0aGluayB0 aGF0J3Mgd2h5DQp0aGVyZSBpcyBjb2RlIGluIHRoZSBTQ1NJIGNvcmUgdG8gYXV0b21hdGljYWxs eSBhZGp1c3QgdGhlIGluaXRpYXRvciBxdWV1ZQ0KZGVwdGggaWYgdGhlICJCVVNZIiBjb25kaXRp b24gaXMgZW5jb3VudGVyZWQgZnJlcXVlbnRseS4gU2VlIGFsc28NCnNjc2lfdHJhY2tfcXVldWVf ZnVsbCgpLg0KDQpCYXJ0Lg==