From: Dexuan Cui Subject: RE: Big I/O requests are split into small ones due to unaligned ext4 partition boundary? Date: Thu, 15 Dec 2016 13:53:52 +0000 Message-ID: References: Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Cc: Jens Axboe , Theodore Ts'o , "Andreas Dilger" , "linux-block@vger.kernel.org" , "linux-ext4@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Abel Hu , Thomas Shao , Matthew Wilcox , Long Li , KY Srinivasan To: Ming Lei Return-path: In-Reply-To: Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org PiBGcm9tOiBNaW5nIExlaSBbbWFpbHRvOnRvbS5sZWltaW5nQGdtYWlsLmNvbV0NCj4gU2VudDog VGh1cnNkYXksIERlY2VtYmVyIDE1LCAyMDE2IDIwOjQzDQo+IA0KPiBPbiBUaHUsIERlYyAxNSwg MjAxNiBhdCA3OjQ3IFBNLCBEZXh1YW4gQ3VpIDxkZWN1aUBtaWNyb3NvZnQuY29tPiB3cm90ZToN Cj4gPiBIaSwgd2hlbiBJIHJ1biAibWtmcy5leHQ0IC9kZXYvc2RjMiIgaW4gYSBMaW51eCB2aXJ0 dWFsIG1hY2hpbmUgb24gSHlwZXItViwNCj4gPiB3aGVyZSBhIGRpc2sgSU9QUz01MDAgbGltaXQg aXMgYXBwbGllZCBieSBtZSBbMF0sICB0aGUgY29tbWFuZCB0YWtlcyBtdWNoDQo+ID4gbW9yZSB0 aW1lLCBpZiB0aGUgZXh0NCBwYXJ0aXRpb24gYm91bmRhcnkgaXMgbm90IHByb3Blcmx5IGFsaWdu ZWQ6DQo+ID4NCj4gPiBFeGFtcGxlIDEgWzFdOiBpdCB0YWtlcyB+NyBtaW51dGVzIHdpdGggYXZl cmFnZSB3TUIvcyA9IDAuMyAgIChzbG93KQ0KPiA+IEV4YW1wbGUgMiBbMl06IGl0IHRha2VzIH4z LjUgbWludXRlcyB3aXRoIGF2ZXJhZ2Ugd01CL3MgPSAwLjYgKHNsb3cpDQo+ID4gRXhhbXBsZSAz IFszXTogaXQgdGFrZXMgfjAuNSBtaW51dGUgd2l0aCBhdmVyYWdlIHdNQi9zID0gNCAoZXhwZWN0 ZWQpDQo+ID4NCj4gPiBzdHJhY2Ugc2hvd3MgdGhlIG1rZnMuZXh0MyBwcm9ncmFtIGNhbGxzIHNl ZWsoKS93cml0ZSgpIGEgbG90IGFuZCBtb3N0IG9mDQo+ID4gdGhlIHdyaXRlcyB1c2UgMzJLQiBi dWZmZXJzICh0aGlzIHNob3VsZCBiZSBiaWcgZW5vdWdoKSwgYW5kIHRoZSBwcm9ncmFtDQo+ID4g b25seSBpbnZva2VzIGZzeW5jKCkgb25jZSwgYWZ0ZXIgaXQgaXNzdWVzIGFsbCB0aGUgd3JpdGVz IC0tIHRoZSBmc3luYygpIHRha2VzDQo+ID4+OTklIG9mIHRoZSB0aW1lLg0KPiA+DQo+ID4gQnkg bG9nZ2luZyBTQ1NJIGNvbW1hbmRzLCB0aGUgU0NTSSBXcml0ZSgxMCkgY29tbWFuZCBpcyB1c2Vk IGhlcmUgZm9yIHRoZQ0KPiA+IHVzZXJzcGFjZSAzMktCIHdyaXRlOg0KPiA+IGluIGV4YW1wbGUg MSwgKmVhY2gqIGNvbW1hbmQgd3JpdGVzIDEgb3IgMiBzZWN0b3JzIG9ubHkgKDEgc2VjdG9yID0g NTEyDQo+IGJ5dGVzKTsNCj4gPiBpbiBleGFtcGxlIDIsICplYWNoKiBjb21tYW5kIHdyaXRlcyAy IG9yIDQgc2VjdG9ycyBvbmx5Ow0KPiA+IGluIGV4YW1wbGUgMywgZWFjaCBjb21tYW5kIHdyaXRl cyAxMDI0IHNlY3RvcnMuDQo+ID4NCj4gPiBJdCBsb29rcyB0aGUga2VybmVsIGJsb2NrIEkvTyBs YXllciBjYW4gc29tZWhvdyBzcGxpdCBiaWcgdXNlci1zcGFjZSBidWZmZXJzDQo+ID4gaW50byBy ZWFsbHkgc21hbGwgd3JpdGUgcmVxdWVzdHMgKDEsIDIsIGFuZCA0IHNlY3RvcnMpPw0KPiA+IFRo aXMgbG9va3MgcmVhbGx5IHN0cmFuZ2UgdG8gbWUuDQo+ID4NCj4gPiBOb3RlOiBpbiBteSB0ZXN0 LCB0aGlzIHN0cmFuZ2UgaXNzdWUgaGFwcGVucyB0byA0LjQgYW5kIHRoZSBtYWlubGluZSA0Ljkg a2VybmVscywNCj4gPiBidXQgdGhlIHN0YWJsZSAzLjE4LjQ1IGtlcm5lbCBkb2Vzbid0IGhhdmUg dGhlIGlzc3VlLCBpLmUuIGFsbCB0aGUgMyBhYm92ZSB0ZXN0DQo+ID4gZXhhbXBsZXMgY2FuIGZp bmlzaCBpbiB+MC41IG1pbnV0ZS4NCj4gPg0KPiA+IEFueSBjb21tZW50Pw0KPiANCj4gSSByZW1l bWJlciB0aGF0IHdlIGRpc2N1c3NlZCB0aGlzIGtpbmQgb2YgaXNzdWUsIHBsZWFzZSBzZWUgdGhl IGRpc2N1c3Npb25bMV0NCj4gYW5kIGNoZWNrIGlmIHRoZSBwYXRjaFsyXSBjYW4gZml4IHlvdXIg aXNzdWUuDQo+IA0KPiBbMV0gaHR0cDovL21hcmMuaW5mby8/dD0xNDU4MDU1MjU1MDAwMDImcj0x Jnc9Mg0KPiBbMl0gaHR0cDovL21hcmMuaW5mby8/bD1saW51eC1rZXJuZWwmbT0xNDU5MzQzMjU0 MjkxNTImdz0yDQo+IA0KPiBNaW5nDQogDQpUaGFuayB5b3UgdmVyeSBtdWNoLCBNaW5nISBUaGUg cGF0Y2ggY2FuIGZpeCBteSBpc3N1ZSENCkl0IGxvb2tzIHlvdXIgcGF0Y2ggd2FzIG5vdCBtZXJn ZWQgaW50byB0aGUgdXBzdHJlYW0gc29tZWhvdy4NCldvdWxkIHlvdSBwbGVhc2Ugc3VibWl0IHRo ZSBwYXRjaCBhZ2Fpbj8NCg0KVGhhbmtzLA0KLS0gRGV4dWFuDQo=