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Fri, 15 Jul 2022 20:12:25 +0900 (KST) Received: from test-zns (unknown [107.110.206.5]) by epsmtip2.samsung.com (KnoxPortal) with ESMTPA id 20220715111223epsmtip243bea6f75bf92c0416d33c21c9e224ea~B-EycOCFr1601816018epsmtip2b; Fri, 15 Jul 2022 11:12:23 +0000 (GMT) Date: Fri, 15 Jul 2022 16:37:00 +0530 From: Kanchan Joshi To: Daniel Wagner Cc: Ming Lei , Sagi Grimberg , Jens Axboe , hch@lst.de, kbusch@kernel.org, io-uring@vger.kernel.org, linux-nvme@lists.infradead.org, linux-block@vger.kernel.org, asml.silence@gmail.com, joshiiitr@gmail.com, anuj20.g@samsung.com, gost.dev@samsung.com Subject: Re: [PATCH for-next 3/4] io_uring: grow a field in struct io_uring_cmd Message-ID: <20220715110700.GA27117@test-zns> MIME-Version: 1.0 In-Reply-To: <20220714153051.5e53zgkcabb7ajms@carbon.lan> User-Agent: Mutt/1.9.4 (2018-02-28) X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFjrEJsWRmVeSWpSXmKPExsWy7bCmuu4s74tJBtO6+C2aJvxltpizahuj xeq7/WwWhx9PYre4eWAnk8XK1UeZLN61nmOxOP/2MJPFpEPXGC323tK2mL/sKbvFocnNTBbr Xr9nceD12DnrLrvH+XsbWTwuny312LSqk81j85J6j903G9g83u+7yubRt2UVo8fm09UenzfJ BXBFZdtkpCampBYppOYl56dk5qXbKnkHxzvHm5oZGOoaWlqYKynkJeam2iq5+AToumXmAF2u pFCWmFMKFApILC5W0rezKcovLUlVyMgvLrFVSi1IySkwKdArTswtLs1L18tLLbEyNDAwMgUq TMjOeNd5irngF1fFonV7WRsYp3F2MXJySAiYSEx9sIMFxBYS2M0ocW2maxcjF5D9iVFiT1sT I4TzmVHi8cObzDAdq+4eZoFI7GKU6Lp1mBXCecYocfTMLjaQKhYBVYl7hycwdTFycLAJaEpc mFwKEhYRUJbY/n8bWDOzwE4miUcPNjCCJIQFAiVW9+5hB7F5BXQlnl8/xgRhC0qcnPkE7D5O AUuJgyfPgtWIAg06sO04E8ggCYELHBKbu64yQZznIjH903OoU4UlXh3fwg5hS0m87G+DspMl Ls08B1VfIvF4z0Eo216i9VQ/WC+zQKbEpQ/T2CBsPone30/AnpEQ4JXoaBOCKFeUuDfpKSuE LS7xcMYSKNtD4uatvWyQQDnKLHHl4HnWCYxys5D8MwvJCgjbSqLzQxPrLKAVzALSEsv/cUCY mhLrd+kvYGRdxSiZWlCcm55abFpgmJdaDo/k5PzcTYzgxKzluYPx7oMPeocYmTgYDzFKcDAr ifB2HzqXJMSbklhZlVqUH19UmpNafIjRFBg/E5mlRJPzgbkhryTe0MTSwMTMzMzE0tjMUEmc 1+vqpiQhgfTEktTs1NSC1CKYPiYOTqkGJo2oH5PqSrbPmBd0JkjIOWHdHrN3vz57FN+PulPP FJN+yKw2Ypvn+n1PyrZ0bwhPfOWrmigZwuJ7dUdd6aMENzaHpllKolNePP900YUld5XVJ/3z 2Qu2qeXKukYrsy41nD5X2Ma6JWWZ5B032zM2/za1HL63bHNO8cZJ+5UWG0w4WNhtN3P1xy6d vaHzA+aWyfue+LafM/irfsO5En2NShG1vMsnlMVlb7Ib/30zhfVW6+wJTucFjBleelcfuMMt HW24jWHy+54iVw/Jsw2/3l4uaGZg/5dmM4/jZc4k+3TlgBKJB/95ej2X6dTcXjeNoeL8m/DJ lfkRuu/SmXd7PjL6/+k2X/1GnWO2Vn7iSizFGYmGWsxFxYkAy3CCulUEAAA= X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFprAIsWRmVeSWpSXmKPExsWy7bCSvO5M74tJBk9ajSyaJvxltpizahuj xeq7/WwWhx9PYre4eWAnk8XK1UeZLN61nmOxOP/2MJPFpEPXGC323tK2mL/sKbvFocnNTBbr Xr9nceD12DnrLrvH+XsbWTwuny312LSqk81j85J6j903G9g83u+7yubRt2UVo8fm09UenzfJ BXBFcdmkpOZklqUW6dslcGXcb/jGVrCSo2Lr9F9MDYz32boYOTkkBEwkVt09zNLFyMUhJLCD UWLxtzWMEAlxieZrP9ghbGGJlf+eg9lCAk8YJX5dCAGxWQRUJe4dnsDUxcjBwSagKXFhcilI WERAWWL7/21gM5kFdjJJrDv5EmyZsECgxOrePWBzeAV0JZ5fP8YEsfg4s8SyBxtZIRKCEidn PmEBsZkFzCTmbX7IDLKAWUBaYvk/DpAwp4ClxMGTZ8HmiAItO7DtONMERsFZSLpnIemehdC9 gJF5FaNkakFxbnpusWGBUV5quV5xYm5xaV66XnJ+7iZGcKRpae1g3LPqg94hRiYOxkOMEhzM SiK83YfOJQnxpiRWVqUW5ccXleakFh9ilOZgURLnvdB1Ml5IID2xJDU7NbUgtQgmy8TBKdXA VP3tjxETa9gMGcurEnpMOWufxU9qD7B3/f7xouNLln3n+R2fSjEs3Fwb02jk/XbbRP/zO/v/ PjcytVXdc+9Hxfqu77+szyy2n2s4ua1POHzynQ6rlRMv7U+x3vzbuMXy8ozm1PIn0w6uMhXJ +ceqcMO/sK7v2T/rkmfBX5Y+a9AyU5nWrHXi4SLDSXzW/aLJy5grLfU0r2zb9vaW6drv597u PrHRZfGcH8cunJrxYu58C5ZnHMt8uP4YPOHdOZ3HPL3llFuI2oTQlC3Ma/69vzvlxqnVU89/ Z/64+6bXiazJyeUWB2fqahXPF5H8IPtLMkcmZGlEnC3DlLerVjuZH5yze/nxP92f7Dacyn5x wvitEktxRqKhFnNRcSIAQmnjCyMDAAA= X-CMS-MailID: 20220715111225epcas5p174b037b8b850300e1ff2d1b96dd0a64d X-Msg-Generator: CA Content-Type: multipart/mixed; boundary="----HMHzcl7Kov5y0bbYah5tgDYyhjafTXQAGx6UUfEgMJOMVZI4=_13446e_" CMS-TYPE: 105P DLP-Filter: Pass X-CFilter-Loop: Reflected X-CMS-RootMailID: 20220711110824epcas5p22c8e945cb8c3c3ac46c8c2b5ab55db9b References: <20220711110155.649153-1-joshi.k@samsung.com> <20220711110155.649153-4-joshi.k@samsung.com> <2b644543-9a54-c6c4-fd94-f2a64d0701fa@kernel.dk> <43955a42-7185-2afc-9a55-80cc2de53bf9@grimberg.me> <96fcba9a-76ad-8e04-e94e-b6ec5934f84e@grimberg.me> <20220714081923.GE30733@test-zns> <20220714153051.5e53zgkcabb7ajms@carbon.lan> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220715_041238_509006_2210CA4D X-CRM114-Status: GOOD ( 17.92 ) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org ------HMHzcl7Kov5y0bbYah5tgDYyhjafTXQAGx6UUfEgMJOMVZI4=_13446e_ Content-Type: text/plain; charset="utf-8"; format="flowed" Content-Disposition: inline On Thu, Jul 14, 2022 at 05:30:51PM +0200, Daniel Wagner wrote: >On Thu, Jul 14, 2022 at 01:49:23PM +0530, Kanchan Joshi wrote: >> If path is not available, retry is not done immediately rather we wait for >> path to be available (as underlying controller may still be >> resetting/connecting). List helped as command gets added into >> it (and submitter/io_uring gets the control back), and retry is done >> exact point in time. >> But yes, it won't harm if we do couple of retries even if path is known >> not to be available (somewhat like iopoll). As this situation is >> not common. And with that scheme, we don't have to link io_uring_cmd. > >Stupid question does it only fail over immediately when the path is not >available or any failure? If it fails over for everything it's possible >the target gets the same request twice. FWIW, we are just debugging this >scenario right now. failover is only for path-related failure, and not otherwise. you might want to take a look at nvme_decide_disposition routine where it makes that decision. ------HMHzcl7Kov5y0bbYah5tgDYyhjafTXQAGx6UUfEgMJOMVZI4=_13446e_ Content-Type: text/plain; charset="utf-8" ------HMHzcl7Kov5y0bbYah5tgDYyhjafTXQAGx6UUfEgMJOMVZI4=_13446e_--