From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Bart Van Assche To: "snitzer@redhat.com" CC: "dm-devel@redhat.com" , "hch@infradead.org" , "linux-block@vger.kernel.org" , "axboe@kernel.dk" , "martin.petersen@oracle.com" , "axboe@fb.com" , "ming.lei@redhat.com" Subject: Re: [PATCH V3 0/5] dm-rq: improve sequential I/O performance Date: Fri, 12 Jan 2018 18:54:49 +0000 Message-ID: <1515783288.2396.37.camel@wdc.com> References: <20180111060159.12991-1-ming.lei@redhat.com> <20180111220742.GA31944@redhat.com> <1515710256.2752.72.camel@sandisk.com> <20180112014232.GB25090@ming.t460p> <20180112015721.GB32298@redhat.com> <20180112033308.GC25090@ming.t460p> <20180112171840.GA4541@redhat.com> <1515778013.2396.3.camel@wdc.com> <20180112174000.GB5134@redhat.com> <1515779211.2396.11.camel@wdc.com> <20180112180635.GD5134@redhat.com> In-Reply-To: <20180112180635.GD5134@redhat.com> Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 List-ID: T24gRnJpLCAyMDE4LTAxLTEyIGF0IDEzOjA2IC0wNTAwLCBNaWtlIFNuaXR6ZXIgd3JvdGU6DQo+ IE9LLCB5b3UgaGF2ZSB0aGUgc3RhZ2U6IHBsZWFzZSBnaXZlIG1lIGEgcG9pbnRlciB0byB5b3Vy IGJlc3QNCj4gZXhwbGFpbmF0aW9uIG9mIHRoZSBzZXZlcmFsLg0KDQpTaW5jZSB0aGUgcHJldmlv dXMgZGlzY3Vzc2lvbiBhYm91dCB0aGlzIHRvcGljIG9jY3VycmVkIG1vcmUgdGhhbiBhIG1vbnRo DQphZ28gaXQgY291bGQgdGFrZSBtb3JlIHRpbWUgdG8gbG9vayB1cCBhbiBleHBsYW5hdGlvbiB0 aGFuIHRvIGV4cGxhaW4gaXQNCmFnYWluLiBBbnl3YXksIGhlcmUgd2UgZ28uIEFzIHlvdSBrbm93 IGEgYmxvY2sgbGF5ZXIgcmVxdWVzdCBxdWV1ZSBuZWVkcyB0bw0KYmUgcmVydW4gaWYgb25lIG9y IG1vcmUgcmVxdWVzdHMgYXJlIHdhaXRpbmcgYW5kIGEgcHJldmlvdXMgY29uZGl0aW9uIHRoYXQN CnByZXZlbnRlZCB0aGUgcmVxdWVzdCB0byBiZSBleGVjdXRlZCBoYXMgYmVlbiBjbGVhcmVkLiBG b3IgdGhlIGRtLW1wYXRoDQpkcml2ZXIsIGV4YW1wbGVzIG9mIHN1Y2ggY29uZGl0aW9ucyBhcmUg bm8gdGFncyBhdmFpbGFibGUsIGEgcGF0aCB0aGF0IGlzDQpidXN5IChzZWUgYWxzbyBwZ3BhdGhf YnVzeSgpKSwgcGF0aCBpbml0aWFsaXphdGlvbiB0aGF0IGlzIGluIHByb2dyZXNzDQoocGdfaW5p dF9pbl9wcm9ncmVzcykgb3IgYSByZXF1ZXN0IGNvbXBsZXRlcyB3aXRoIHN0YXR1cywgZS5nLiBp ZiB0aGUNClNDU0kgY29yZSBjYWxscyBfX2Jsa19tcV9lbmRfcmVxdWVzdChyZXEsIGVycm9yKSB3 aXRoIGVycm9yICE9IDAuIEZvciBzb21lDQpvZiB0aGVzZSBjb25kaXRpb25zLCBlLmcuIHBhdGgg aW5pdGlhbGl6YXRpb24gY29tcGxldGVzLCBhIGNhbGxiYWNrDQpmdW5jdGlvbiBpbiB0aGUgZG0t bXBhdGggZHJpdmVyIGlzIGNhbGxlZCBhbmQgaXQgaXMgcG9zc2libGUgdG8gZXhwbGljaXRseQ0K cmVydW4gdGhlIHF1ZXVlLiBJIGFncmVlIHRoYXQgZm9yIHN1Y2ggc2NlbmFyaW8ncyBhIGRlbGF5 ZWQgcXVldWUgcnVuIHNob3VsZA0Kbm90IGJlIHRyaWdnZXJlZC4gRm9yIG90aGVyIHNjZW5hcmlv J3MsIGUuZy4gaWYgYSBTQ1NJIGluaXRpYXRvciBzdWJtaXRzIGENClNDU0kgcmVxdWVzdCBvdmVy IGEgZmFicmljIGFuZCB0aGUgU0NTSSB0YXJnZXQgcmVwbGllcyB3aXRoICJCVVNZIiB0aGVuIHRo ZQ0KU0NTSSBjb3JlIHdpbGwgZW5kIHRoZSBJL08gcmVxdWVzdCB3aXRoIHN0YXR1cyBCTEtfU1RT X1JFU09VUkNFIGFmdGVyIHRoZQ0KbWF4aW11bSBudW1iZXIgb2YgcmV0cmllcyBoYXMgYmVlbiBy ZWFjaGVkIChzZWUgYWxzbyBzY3NpX2lvX2NvbXBsZXRpb24oKSkuDQpJbiB0aGF0IGxhc3QgY2Fz ZSwgaWYgYSBTQ1NJIHRhcmdldCBzZW5kcyBhICJCVVNZIiByZXBseSBvdmVyIHRoZSB3aXJlIGJh Y2sNCnRvIHRoZSBpbml0aWF0b3IsIHRoZXJlIGlzIG5vIG90aGVyIGFwcHJvYWNoIGZvciB0aGUg U0NTSSBpbml0aWF0b3IgdG8NCmZpZ3VyZSBvdXQgd2hldGhlciBpdCBjYW4gcXVldWUgYW5vdGhl ciByZXF1ZXN0IHRoYW4gdG8gcmVzdWJtaXQgdGhlDQpyZXF1ZXN0LiBUaGUgd29yc3QgcG9zc2li bGUgc3RyYXRlZ3kgaXMgdG8gcmVzdWJtaXQgYSByZXF1ZXN0IGltbWVkaWF0ZWx5DQpiZWNhdXNl IHRoYXQgd2lsbCBjYXVzZSBhIHNpZ25pZmljYW50IGZyYWN0aW9uIG9mIHRoZSBmYWJyaWMgYmFu ZHdpZHRoIHRvDQpiZSB1c2VkIGp1c3QgZm9yIHJlcGx5aW5nICJCVVNZIiB0byByZXF1ZXN0cyB0 aGF0IGNhbid0IGJlIHByb2Nlc3NlZA0KaW1tZWRpYXRlbHkuDQoNClRoZSBpbnRlbnRpb24gb2Yg Y29tbWl0IDYwNzdjMmQ3MDYwOTdjMCB3YXMgdG8gYWRkcmVzcyB0aGUgbGFzdCBtZW50aW9uZWQN CmNhc2UuIEl0IG1heSBiZSBwb3NzaWJsZSB0byBtb3ZlIHRoZSBkZWxheWVkIHF1ZXVlIHJlcnVu IGZyb20gdGhlDQpkbV9xdWV1ZV9ycSgpIGludG8gZG1fcmVxdWV1ZV9vcmlnaW5hbF9yZXF1ZXN0 KCkuIEJ1dCBJIHRoaW5rIGl0IHdvdWxkIGJlDQp3cm9uZyB0byByZXJ1biB0aGUgcXVldWUgaW1t ZWRpYXRlbHkgaW4gY2FzZSBhIFNDU0kgdGFyZ2V0IHN5c3RlbSByZXR1cm5zDQoiQlVTWSIuDQoN CkJhcnQu