From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailout1.w1.samsung.com (mailout1.w1.samsung.com [210.118.77.11]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CC217132106 for ; Fri, 4 Oct 2024 06:52:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=210.118.77.11 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728024759; cv=none; b=J7lEZrE99fLZx4HL9/nzzLe5jN3qH/MkDRghsZzLldvh8FmnIXrhfq5aDUN1ESCxQF4IQTt9yEfIxh7OyfUuwc+GmojNHxux49z20vE5/FV3yYZ3V+60I01ZM5BljsHW7jdLChrIq84maeyz47jxeVLSSmjlbKDo44umZUZQwmw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728024759; c=relaxed/simple; bh=4eq/fuIBDdbYh7Urv9+9/tFmFzYnb705DDsjr2gXdU4=; h=Date:From:To:CC:Subject:Message-ID:MIME-Version:Content-Type: Content-Disposition:In-Reply-To:References; b=G6daBzplQo7BL8G8uPkwvHTn0SxO5o3AQOEcn540fcG/RL/tgxmNgRBHz4jgcl2vAVtgS4BSZIndeQuDxQeFY4jo+bc0W11sFQZaKn+mPMGWNRMuKlVq7A3wQtXN4yN+wGnzDJYlq/zkZ86m1Zl3CCtbQEh+eBwIaKc8yS8kj04= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=samsung.com; spf=pass smtp.mailfrom=samsung.com; dkim=pass (1024-bit key) header.d=samsung.com header.i=@samsung.com header.b=MH7zdzIV; arc=none smtp.client-ip=210.118.77.11 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=samsung.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=samsung.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=samsung.com header.i=@samsung.com header.b="MH7zdzIV" Received: from eucas1p2.samsung.com (unknown [182.198.249.207]) by mailout1.w1.samsung.com (KnoxPortal) with ESMTP id 20241004065236euoutp011fbbe8cd319da6954b5f80f87b630435~7LVw3u5Hh2169021690euoutp01G for ; Fri, 4 Oct 2024 06:52:36 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 mailout1.w1.samsung.com 20241004065236euoutp011fbbe8cd319da6954b5f80f87b630435~7LVw3u5Hh2169021690euoutp01G DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=samsung.com; s=mail20170921; t=1728024756; bh=0eFNEuun/51sigt8I1IGkMHFvF9oS3OdSQuK/gZtlIw=; h=Date:From:To:CC:Subject:In-Reply-To:References:From; b=MH7zdzIVDjgABsfiX9kLixNYQzWuaUVJr+R9+48gPbOXKM+mI4eWQG2o/vJv6etzQ /RI+xaZT6B4e0KiodSQSu6q2CmEP/y+5BbW34CNq0e23cCGZKtgfDCSO1C9fksiT/I 5c8n4HOfobpfJQMuSCkWvKaaFs/GjvO9tG7GjIkE= Received: from eusmges3new.samsung.com (unknown [203.254.199.245]) by eucas1p2.samsung.com (KnoxPortal) with ESMTP id 20241004065235eucas1p2985f211d5f3c64b317e37c43d118866a~7LVwiIpBo3244832448eucas1p2Q; Fri, 4 Oct 2024 06:52:35 +0000 (GMT) Received: from eucas1p1.samsung.com ( [182.198.249.206]) by eusmges3new.samsung.com (EUCPMTA) with SMTP id 25.97.09620.3B09FF66; Fri, 4 Oct 2024 07:52:35 +0100 (BST) Received: from eusmtrp1.samsung.com (unknown [182.198.249.138]) by eucas1p1.samsung.com (KnoxPortal) with ESMTPA id 20241004065235eucas1p102ea903dc060b880ee9dd7137ae436dd~7LVwD71F51940419404eucas1p1S; Fri, 4 Oct 2024 06:52:35 +0000 (GMT) Received: from eusmgms2.samsung.com (unknown [182.198.249.180]) by eusmtrp1.samsung.com (KnoxPortal) with ESMTP id 20241004065235eusmtrp1b2a790e78aedd380db26f9caf681a26e~7LVwC2K6V0078200782eusmtrp1F; Fri, 4 Oct 2024 06:52:35 +0000 (GMT) X-AuditID: cbfec7f5-d31ff70000002594-20-66ff90b3914f Received: from eusmtip2.samsung.com ( [203.254.199.222]) by eusmgms2.samsung.com (EUCPMTA) with SMTP id A6.E4.19096.3B09FF66; Fri, 4 Oct 2024 07:52:35 +0100 (BST) Received: from CAMSVWEXC02.scsc.local (unknown [106.1.227.72]) by eusmtip2.samsung.com (KnoxPortal) with ESMTPA id 20241004065235eusmtip222a3c0d6fe5a11c3e12e6292908b3360~7LVv3brZh2337823378eusmtip2R; Fri, 4 Oct 2024 06:52:35 +0000 (GMT) Received: from localhost (106.110.32.122) by CAMSVWEXC02.scsc.local (2002:6a01:e348::6a01:e348) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Fri, 4 Oct 2024 07:52:34 +0100 Date: Fri, 4 Oct 2024 08:52:33 +0200 From: Javier =?utf-8?B?R29uesOhbGV6?= To: Christoph Hellwig CC: Jens Axboe , "Martin K. Petersen" , Keith Busch , Kanchan Joshi , , , , , , , , , , , , , , , , , Subject: Re: [PATCH v7 0/3] FDP and per-io hints Message-ID: <20241004065233.oc5gqcq3lyaxzjhz@ArmHalley.local> Precedence: bulk X-Mailing-List: io-uring@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8"; format="flowed" Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20241004062733.GB14876@lst.de> X-ClientProxiedBy: CAMSVWEXC01.scsc.local (2002:6a01:e347::6a01:e347) To CAMSVWEXC02.scsc.local (2002:6a01:e348::6a01:e348) X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFmpgk+LIzCtJLcpLzFFi42LZduznOd3NE/6nGczYoW4xZ9U2RovVd/vZ LLr+bWGxeH34E6PFtA8/mS3eNf1msdizaBKTxcrVR5ks3rWeY7GYPb2ZyeLJ+lnMFpMOXWO0 mDKtidFi7y1tiz17T7JYzF/2lN1i+fF/TBbrXr9nsTj/9zirg7DH5SveHjtn3WX3OH9vI4vH 5bOlHptWdbJ5bPo0id1j85J6j903G9g8Pj69xeLxft9VNo8zC44AxU9Xe3zeJOex6clbpgC+ KC6blNSczLLUIn27BK6Mhzu2sBUskqxYO/0OWwPjZJEuRk4OCQETib4DK5lAbCGBFYwS/2ZE djFyAdlfGCVmth9hhnA+M0rsOPGEGabjTc9NdojEckaJC5c/ssJVHXzzASjDAeRsZpS4JgPS wCKgIjH9/w4WEJtNwF7i0rJbYINEBJQknr46ywjSyyxwiEXiy4H57CAJYQEDifffe9lAbF4B W4m29XcYIWxBiZMzn4ANYhawkuj80MQKsotZQFpi+T8OiLC8RPPW2WDzOQV0JBZsvs8CcbSS xOMXbxkh7FqJU1tuMYHslRDo4pL48WsH1GcuEgtfHGGHsIUlXh3fAmXLSJye3AM1qFqi4eQJ qOYWRonWjq1gR0gIWEv0ncmBqHGUeDX9JztEmE/ixltBiNv4JCZtm84MEeaV6GgTmsCoMgvJ Y7OQPDYL4bFZSB5bwMiyilE8tbQ4Nz212DgvtVyvODG3uDQvXS85P3cTIzCRnv53/OsOxhWv PuodYmTiYDzEKMHBrCTCO2/73zQh3pTEyqrUovz4otKc1OJDjNIcLErivKop8qlCAumJJanZ qakFqUUwWSYOTqkGJr8DXa0lUaqdHSrLIibar2GP3rxc3voRyyKr6+5fqidp2jw8ZPXIp6y+ 7sHVPoaVv5fl2Ccnpy5/0CPz65Nwa9zvGwXS6eKnGS7+2rE71o7tm963cpPrC47MjlWcdubO MT7fube/xxd2b59pOeNUReDLKYxbWblnyHn7nSu4q9y6N3TZvvnqeZvE+Ur1Qh696/YqYQ9V q3A5v/pYnPqXO8cO/JS2mSHpk99q/nYS47mYVW1TbG5N+3YvN6RcvLqjSDzSbU61y7GJ9Zcv Ghne3tW09vzLt0/4r26bbJvxoqY3/vCtt8wHcsofeDxI+Kz5LHhp1PHLn3lappkfjqtbz72e ecfvnzeWqOZYtipf3aLEUpyRaKjFXFScCAAMV0+WEwQAAA== X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFlrLKsWRmVeSWpSXmKPExsVy+t/xe7qbJ/xPM7jfxWUxZ9U2RovVd/vZ LLr+bWGxeH34E6PFtA8/mS3eNf1msdizaBKTxcrVR5ks3rWeY7GYPb2ZyeLJ+lnMFpMOXWO0 mDKtidFi7y1tiz17T7JYzF/2lN1i+fF/TBbrXr9nsTj/9zirg7DH5SveHjtn3WX3OH9vI4vH 5bOlHptWdbJ5bPo0id1j85J6j903G9g8Pj69xeLxft9VNo8zC44AxU9Xe3zeJOex6clbpgC+ KD2bovzSklSFjPziElulaEMLIz1DSws9IxNLPUNj81grI1MlfTublNSczLLUIn27BL2Mhzu2 sBUskqxYO/0OWwPjZJEuRk4OCQETiTc9N9m7GLk4hASWMkrcu7KeESIhI7Hxy1VWCFtY4s+1 LjaIoo+MEgtvz2GGcDYzSmx++Qesg0VARWL6/x0sIDabgL3EpWW3mEFsEQEliaevzjKCNDAL HGKR+HJgPjtIQljAQOL99142EJtXwFaibf0dRoipZ5gl3m3tY4RICEqcnPkEbCqzgIXEzPnn geIcQLa0xPJ/HBBheYnmrbPBlnEK6Egs2HyfBeJsJYnHL95CvVMr8fnvM8YJjCKzkEydhWTq LISps5BMXcDIsopRJLW0ODc9t9hIrzgxt7g0L10vOT93EyMw3Ww79nPLDsaVrz7qHWJk4mA8 xCjBwawkwjtv+980Id6UxMqq1KL8+KLSnNTiQ4ymwDCayCwlmpwPTHh5JfGGZgamhiZmlgam lmbGSuK8bFfOpwkJpCeWpGanphakFsH0MXFwSjUw1eled5OI3XlGl9nK1elXwPbrM4VLm/+W 3lXTTWt9xt1xXLW6dcvpZLbPMmFtdxyOTMr6+LOl86npupJFTF5hl2NSzM9VnbL8pNqTnJMV 5yMifm+Rwh7PRXfMQj0+eK+8YyGYUf5kRewzAcEWaWmz71sTmJfF1jenZzsdyD477cGx2bO2 +PBvtbGd7GtVfUzy7rraw0kvPA49vnjVPdZiwaKndo7/P7+pryoLvp/RvuP4747Alazchzgs C7+LWXSdr62pP5AjYKwsv11k/24lsWNH9EMXnk2V/sRqqK7IsGBpY9bxoC+28cL8x9057b52 c2S5XtCxXFAloPHr74ySQqvTIRqrFLdH9qW/11JiKc5INNRiLipOBADL+ORQwAMAAA== X-CMS-MailID: 20241004065235eucas1p102ea903dc060b880ee9dd7137ae436dd X-Msg-Generator: CA X-RootMTR: 20241004053129eucas1p2aa4888a11a20a1a6287e7a32bbf3316b X-EPHeader: CA CMS-TYPE: 201P X-CMS-RootMailID: 20241004053129eucas1p2aa4888a11a20a1a6287e7a32bbf3316b References: <20241002151344.GA20364@lst.de> <20241002151949.GA20877@lst.de> <20241003125400.GB17031@lst.de> <20241004053121.GB14265@lst.de> <20241004061811.hxhzj4n2juqaws7d@ArmHalley.local> <20241004062733.GB14876@lst.de> On 04.10.2024 08:27, Christoph Hellwig wrote: >On Fri, Oct 04, 2024 at 08:18:11AM +0200, Javier González wrote: >>> And for anyone who followed the previous discussions of the patches >>> none of this should been new, each point has been made at least three >>> times before. >> >> Looking at the work you and Hans have been doing on XFS, it seems you >> have been successful at mapping the semantics of the temperature to >> zones (which has no semantics, just as FDP). >> >> What is the difference between the mapping in zones and for FDP? > >Probably not much, except for all the pitfalls in the FDP not quite hint >not madatory design. It is too late to change the first version of FDP productas, and the solution of "go back to NVMe and make it match SCSI" is not realistic. We have drives from several companies out there supporting this version of FDP. And we have customers that are actively using them. It is our collective responsibility to support them. So, considerign that file system _are_ able to use temperature hints and actually make them work, why don't we support FDP the same way we are supporting zones so that people can use it in production? I agree that down the road, an interface that allows hints (many more than 5!) is needed. And in my opinion, this interface should not have semintics attached to it, just a hint ID, #hints, and enough space to put 100s of them to support storage node deployments. But this needs to come from the users of the hints / zones / streams / etc, not from us vendors. We do not have neither details on how they deploy these features at scale, nor the workloads to validate the results. Anything else will probably just continue polluting the storage stack with more interfaces that are not used and add to the problem of data placement fragmentation. > >> The whole point is using an existing interface to cover the use-case of >> people wanting hints in block. > >And that's fine. And that point all the way back for month is that >doing a complete dumb mapping in the driver for that is fundamentally >wrong. Kanchan's previous series did about 50% of the work to get >it rid, but then everyone dropped dead and played politics. The issue is that the first series of this patch, which is as simple as it gets, hit the list in May. Since then we are down paths that lead nowhere. So the line between real technical feedback that leads to a feature being merged, and technical misleading to make people be a busy bee becomes very thin. In the whole data placement effort, we have been down this path many times, unfortunately... At LPC, we discussed about the work you did in XFS and it became clear that coming back to the first version of the patches was the easiest way to support the use-case that current customers have. It is a pity you did not attend the conference and could make a point against this line of thought there. So summarizing, all folks in this thread are asking is for a path to move forward for solving the block use-case, which is the only one that I am aware of requiring kernel support. This has been validated with real workloads, so it is very specific and tangible.