From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Bart Van Assche To: "ming.lei@redhat.com" , "snitzer@redhat.com" , "axboe@kernel.dk" CC: "dm-devel@redhat.com" , "linux-kernel@vger.kernel.org" , "hch@infradead.org" , "linux-block@vger.kernel.org" , "osandov@fb.com" Subject: Re: [PATCH] block: neutralize blk_insert_cloned_request IO stall regression (was: Re: [RFC PATCH] blk-mq: fixup RESTART when queue becomes idle) Date: Tue, 23 Jan 2018 16:43:42 +0000 Message-ID: <1516725821.3339.11.camel@wdc.com> References: <1516296056.2676.23.camel@wdc.com> <20180118183039.GA20121@redhat.com> <1516301278.2676.35.camel@wdc.com> <20180118204856.GA31679@redhat.com> <1516309128.2676.38.camel@wdc.com> <20180118212327.GB31679@redhat.com> <1516311554.2676.50.camel@wdc.com> <20180118220132.GA20860@redhat.com> <1516314012.2676.76.camel@wdc.com> <20180123092204.GA39002@redhat.com> In-Reply-To: <20180123092204.GA39002@redhat.com> Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 List-ID: T24gVHVlLCAyMDE4LTAxLTIzIGF0IDEwOjIyICswMTAwLCBNaWtlIFNuaXR6ZXIgd3JvdGU6DQo+ IE9uIFRodSwgSmFuIDE4IDIwMTggYXQgIDU6MjBwbSAtMDUwMCwNCj4gQmFydCBWYW4gQXNzY2hl IDxCYXJ0LlZhbkFzc2NoZUB3ZGMuY29tPiB3cm90ZToNCj4gDQo+ID4gT24gVGh1LCAyMDE4LTAx LTE4IGF0IDE3OjAxIC0wNTAwLCBNaWtlIFNuaXR6ZXIgd3JvdGU6DQo+ID4gPiBBbmQgeWV0IExh dXJlbmNlIGNhbm5vdCByZXByb2R1Y2UgYW55IHN1Y2ggbG9ja3VwcyB3aXRoIHlvdXIgdGVzdC4u Lg0KPiA+IA0KPiA+IEhtbSAuLi4gbWF5YmUgSSBtaXN1bmRlcnN0b29kIExhdXJlbmNlIGJ1dCBJ IGRvbid0IHRoaW5rIHRoYXQgTGF1cmVuY2UgaGFzDQo+ID4gYWxyZWFkeSBzdWNjZWVkZWQgYXQg cnVubmluZyBhbiB1bm1vZGlmaWVkIHZlcnNpb24gb2YgbXkgdGVzdHMuIEluIG9uZSBvZiB0aGUN Cj4gPiBlLW1haWxzIExhdXJlbmNlIHNlbnQgbWUgdGhpcyBtb3JuaW5nIEkgcmVhZCB0aGF0IGhl IG1vZGlmaWVkIHRoZXNlIHNjcmlwdHMNCj4gPiB0byBnZXQgcGFzdCBhIGtlcm5lbCBtb2R1bGUg dW5sb2FkIGZhaWx1cmUgdGhhdCB3YXMgcmVwb3J0ZWQgd2hpbGUgc3RhcnRpbmcNCj4gPiB0aGVz ZSB0ZXN0cy4gU28gdGhlIG5leHQgc3RlcCBpcyB0byBjaGVjayB3aGljaCBjaGFuZ2VzIHdlcmUg bWFkZSB0byB0aGUgdGVzdA0KPiA+IHNjcmlwdHMgYW5kIGFsc28gd2hldGhlciB0aGUgdGVzdCBy ZXN1bHRzIGFyZSBzdGlsbCB2YWxpZC4NCj4gPiANCj4gPiA+IEFyZSB5b3UgYWJzb2x1dGVseSBj ZXJ0YWluIHRoaXMgcGF0Y2ggZG9lc24ndCBoZWxwIHlvdT8NCj4gPiA+IGh0dHBzOi8vcGF0Y2h3 b3JrLmtlcm5lbC5vcmcvcGF0Y2gvMTAxNzQwMzcvDQo+ID4gPiANCj4gPiA+IElmIGl0IGRvZXNu J3QgdGhlbiB0aGF0IGlzIGFjdHVhbGx5IHZlcnkgdXNlZnVsIHRvIGtub3cuDQo+ID4gDQo+ID4g VGhlIGZpcnN0IEkgdHJpZWQgdGhpcyBtb3JuaW5nIGlzIHRvIHJ1biB0aGUgc3JwLXRlc3Qgc29m dHdhcmUgYWdhaW5zdCBhIG1lcmdlDQo+ID4gb2YgSmVucycgZm9yLW5leHQgYnJhbmNoIGFuZCB5 b3VyIGRtLTQuMTYgYnJhbmNoLiBTaW5jZSBJIG5vdGljZWQgdGhhdCB0aGUgZG0NCj4gPiBxdWV1 ZSBsb2NrZWQgdXAgSSByZWluc2VydGVkIGEgYmxrX21xX2RlbGF5X3J1bl9od19xdWV1ZSgpIGNh bGwgaW4gdGhlIGRtIGNvZGUuDQo+ID4gU2luY2UgZXZlbiB0aGF0IHdhcyBub3Qgc3VmZmljaWVu dCBJIHRyaWVkIHRvIGtpY2sgdGhlIHF1ZXVlcyB2aWEgZGVidWdmcyAoZm9yDQo+ID4gcyBpbiAv c3lzL2tlcm5lbC9kZWJ1Zy9ibG9jay8qL3N0YXRlOyBkbyBlY2hvIGtpY2sgPiRzOyBkb25lKS4g U2luY2UgdGhhdCB3YXMNCj4gPiBub3Qgc3VmZmljaWVudCB0byByZXNvbHZlIHRoZSBxdWV1ZSBz dGFsbCBJIHJldmVydGVkIHRoZSBmb2xsb3dpbmcgdHJlZSBwYXRjaGVzDQo+ID4gdGhhdCBhcmUg aW4gSmVucycgdHJlZToNCj4gPiAqICJibGstbXE6IGltcHJvdmUgRE0ncyBibGstbXEgSU8gbWVy Z2luZyB2aWEgYmxrX2luc2VydF9jbG9uZWRfcmVxdWVzdCBmZWVkYmFjayINCj4gPiAqICJibGst bXEtc2NoZWQ6IHJlbW92ZSB1bnVzZWQgJ2Nhbl9ibG9jaycgYXJnIGZyb20gYmxrX21xX3NjaGVk X2luc2VydF9yZXF1ZXN0Ig0KPiA+ICogImJsay1tcTogZG9uJ3QgZGlzcGF0Y2ggcmVxdWVzdCBp biBibGtfbXFfcmVxdWVzdF9kaXJlY3RfaXNzdWUgaWYgcXVldWUgaXMgYnVzeSINCj4gPiANCj4g PiBPbmx5IGFmdGVyIEkgaGFkIGRvbmUgdGhpcyB0aGUgc3JwLXRlc3Qgc29mdHdhcmUgcmFuIGFn YWluIHdpdGhvdXQgdHJpZ2dlcmluZw0KPiA+IGRtIHF1ZXVlIGxvY2t1cHMuDQoNCkhlbGxvIE1p a2UsDQoNCkkgd2FudCB0byB0YWtlIGJhY2sgd2hhdCBJIHdyb3RlIGFib3V0IHRoZSByZXZlcnRz LiBJIGhhdmUgbm90IHlldCB0cmllZCB0bw0KYW5hbHl6ZSBleGFjdGx5IHdoaWNoIGNoYW5nZSBt YWRlIGJsa19pbnNlcnRfY2xvbmVkX3JlcXVlc3QoKSB3b3JrIHJlbGlhYmx5DQpmb3IgbWUgYnV0 IHdpdGggSmVucycgbGF0ZXN0IGZvci1uZXh0IGJyYW5jaCBhbmQgeW91ciBmb3ItNC4xNiBicmFu Y2ggbWVyZ2VkDQphbGwgSSBuZWVkIHRvIGF2b2lkIHF1ZXVlIHN0YWxscyBpcyB0aGUgZm9sbG93 aW5nOg0KDQpkaWZmIC0tZ2l0IGEvZHJpdmVycy9tZC9kbS1ycS5jIGIvZHJpdmVycy9tZC9kbS1y cS5jDQppbmRleCBmMTYwOTZhZjg3OWEuLmM1OWM1OWNmZDJhNSAxMDA2NDQNCi0tLSBhL2RyaXZl cnMvbWQvZG0tcnEuYw0KKysrIGIvZHJpdmVycy9tZC9kbS1ycS5jDQpAQCAtNzYxLDYgKzc2MSw3 IEBAIHN0YXRpYyBibGtfc3RhdHVzX3QgZG1fbXFfcXVldWVfcnEoc3RydWN0IGJsa19tcV9od19j dHggKmhjdHgsDQogCQkvKiBVbmRvIGRtX3N0YXJ0X3JlcXVlc3QoKSBiZWZvcmUgcmVxdWV1aW5n ICovDQogCQlycV9lbmRfc3RhdHMobWQsIHJxKTsNCiAJCXJxX2NvbXBsZXRlZChtZCwgcnFfZGF0 YV9kaXIocnEpLCBmYWxzZSk7DQorCQlibGtfbXFfZGVsYXlfcnVuX2h3X3F1ZXVlKGhjdHgsIDEw MC8qbXMqLyk7DQogCQlyZXR1cm4gQkxLX1NUU19SRVNPVVJDRTsNCiAJfQ0KIA0KQmFydC4=