From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailout2.samsung.com (mailout2.samsung.com [203.254.224.25]) (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 8808D1DA2FE for ; Wed, 4 Sep 2024 15:03:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=203.254.224.25 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725462234; cv=none; b=IN+oWWEYQzS+febrfl7KMAe+lFb7XfQANRNOr/laWftY0S8lphndhTJ7LrBEbeMJRoeiPOWuqOeooHyGR7VUiLNKCaFkMeyiT16lU0/vZ518jxZ17ILG1/LIJKqRnfJv4POgkwAsIu7faZYzj68+jZYc9d3bQCSKvtuMjeSuvy4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725462234; c=relaxed/simple; bh=2MNDvJdAuFrKPaz7AKdeoAkNagaHCANVw+2OvyTUO+8=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:From:In-Reply-To: Content-Type:References; b=XJNCmXWJoEdRrttaNTcGUH4fhEshitFU9vvFBG7CTk6dw45LOmZpbKhXE/jt2WMmsR8FpW0B1szT314bf6B6pS2wNDkfYUzItAGYR4Huu0cEzr970/9F6lJjk/dhNjYsp1kefxVBW5E49wsbSu87VMb0mXFyClKiR7xbYRM6lmo= 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=tq7EDcon; arc=none smtp.client-ip=203.254.224.25 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="tq7EDcon" Received: from epcas5p2.samsung.com (unknown [182.195.41.40]) by mailout2.samsung.com (KnoxPortal) with ESMTP id 20240904145712epoutp02bda6293aa88f8745098317e95531113b~yEmUnXqav2704327043epoutp021 for ; Wed, 4 Sep 2024 14:57:12 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 mailout2.samsung.com 20240904145712epoutp02bda6293aa88f8745098317e95531113b~yEmUnXqav2704327043epoutp021 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=samsung.com; s=mail20170921; t=1725461832; bh=/XD9MSPm2ieh7tYbx02NG5OSwwR0Rs4WQ1DiKKxiIlc=; h=Date:Subject:To:Cc:From:In-Reply-To:References:From; b=tq7EDconfAAxtqzrR0A2EYizCmpDG4aADIRh7WMATDaYhe7mBUC+hV/f4w95OCHbG N3tropibV5reJDG9mXkx7U1E0Meop0P+bWBeP7knpW19vZ9Z1UWdqtvZvyvmbm4eh4 8vbbQ0LhF4GRsWACIy5UaJFd4WRbZq3W/VNGW+ck= Received: from epsnrtp3.localdomain (unknown [182.195.42.164]) by epcas5p1.samsung.com (KnoxPortal) with ESMTP id 20240904145712epcas5p16b1e59b36b65364e750ad6186f3c40c0~yEmT86gsc0537605376epcas5p1a; Wed, 4 Sep 2024 14:57:12 +0000 (GMT) Received: from epsmges5p2new.samsung.com (unknown [182.195.38.179]) by epsnrtp3.localdomain (Postfix) with ESMTP id 4WzQZG2H28z4x9Pt; Wed, 4 Sep 2024 14:57:10 +0000 (GMT) Received: from epcas5p2.samsung.com ( [182.195.41.40]) by epsmges5p2new.samsung.com (Symantec Messaging Gateway) with SMTP id 02.09.09743.64578D66; Wed, 4 Sep 2024 23:57:10 +0900 (KST) Received: from epsmtrp2.samsung.com (unknown [182.195.40.14]) by epcas5p1.samsung.com (KnoxPortal) with ESMTPA id 20240904145709epcas5p1500f0810833c70c779c5b5d911fa7842~yEmRhvbRj0635006350epcas5p1x; Wed, 4 Sep 2024 14:57:09 +0000 (GMT) Received: from epsmgms1p1new.samsung.com (unknown [182.195.42.41]) by epsmtrp2.samsung.com (KnoxPortal) with ESMTP id 20240904145709epsmtrp2579123e002487ee76c7e08d31d1d3da9~yEmRfmIxb0123901239epsmtrp25; Wed, 4 Sep 2024 14:57:09 +0000 (GMT) X-AuditID: b6c32a4a-14fff7000000260f-69-66d875463bee Received: from epsmtip2.samsung.com ( [182.195.34.31]) by epsmgms1p1new.samsung.com (Symantec Messaging Gateway) with SMTP id 8A.1B.08964.54578D66; Wed, 4 Sep 2024 23:57:09 +0900 (KST) Received: from [107.122.11.51] (unknown [107.122.11.51]) by epsmtip2.samsung.com (KnoxPortal) with ESMTPA id 20240904145705epsmtip23467e1ecdd38069c57e5f46971b556e1~yEmN4AJW22167321673epsmtip2W; Wed, 4 Sep 2024 14:57:05 +0000 (GMT) Message-ID: Date: Wed, 4 Sep 2024 20:27:04 +0530 Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.8.1 Subject: Re: [PATCH v4 0/5] Write-placement hints and FDP Content-Language: en-US To: Christian Brauner Cc: amir73il@gmail.com, kbusch@kernel.org, hch@lst.de, sagi@grimberg.me, martin.petersen@oracle.com, James.Bottomley@hansenpartnership.com, jack@suse.cz, jaegeuk@kernel.org, jlayton@kernel.org, chuck.lever@oracle.com, bvanassche@acm.org, "axboe@kernel.dk" , linux-nvme@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-block@vger.kernel.org, linux-scsi@vger.kernel.org, gost.dev@samsung.com, vishak.g@samsung.com, javier.gonz@samsung.com From: Kanchan Joshi In-Reply-To: <20240903-erfassen-bandmitglieder-32dfaeee66b2@brauner> Content-Transfer-Encoding: 7bit X-Brightmail-Tracker: H4sIAAAAAAAAA01TbUxbZRTOe3t7e8HUXAvIa1VgjSyOCaN8eVkATSRwwyASly3zI0IHF1pb 2q63ZRshSmCbfGyjsIXOgqFWBAfKhCLjYxhSRLYJgiKDEj5dEUcFxrqgSHW2tFP+Pe85z3Oe 95yTg7N4xRw+LpGraZVcJBNg3mjnwL4XQ5M0UznhzZtPkGOtLYBsma3ESNvAA0DW3N9ikY9m lxHS0t+NkFdbBhGyVleCkNZrehbZVomTd2fsHHKrsZlDVpvvALJvej/5kzGZvNF3CyXrG5c4 ZMVkF0Y2Df2DkK22dZQc1ddxXvWjxn8+RHXrZznU6FwbStVU38ao8REN1d5chlGmhg+oXoMd oXotRRi1sTSNUhc7mgE1bPiWQ9nbA9K5b0njxLQom1YF0fIsRbZEnhsvOHQ447WM6JhwYagw lnxZECQX5dHxgsTU9NAkiczZriAoXyTTOEPpIoYRHEiIUyk0ajpIrGDU8QJamS1TRinDGFEe o5Hnhslp9UFheHhEtJOYKRU3XOhnK+9wT63rv+cUgS3vcuCFQyIKNn1twMqBN84jegFcrqpl ux8PABzsn/VkNgEc0J5FH0t05j/ZLswj+gC0lu5xk1YBvFSxDlwJLpEAtyoaEBdGiRfgRslV zB1/Ct76yLpTyI84Dv+aqNvh+xCx0DyyulOURfjDaWv9jtaXCIHFxg3EZcAizqBwcGnQKcZx jNgHxy5pXBwvIhFum2qBWxsIr6/WsdwfbfGCcyMenAgbOwc82AeuDHVw3JgP7Wt9mBtL4cIv C54mC2GX6SLbjV+BRY4ptsuW5bS91nPAbfUkvLBtRVxhSHBh6Tmem70HzlUveZT+cPFKgwdT cLr3oWeeDgA7iu2YFgTpd01Fv6t7/a5u9P87GwDaDJ6hlUxeLs1EKyPk9Mn/9p2lyGsHO8cQ ktIFFhfuh5kBggMzgDhL4Mu1+U7l8LjZotMFtEqRodLIaMYMop3rqWLx/bIUzmuSqzOEUbHh UTExMVGxkTFCgT/XdvbjbB6RK1LTUppW0qrHOgT34hchpWud22cqr0Re/+Z3m3g+2Jb54f76 ma5yn758B2bybtWl/j3En3y/pyAt2cGSls3mrCSuWy3lPZZPPv2uKha3J6T98NXEwFYE9D4f vfcLo3Av89x4sOmuJjOsxP6bXOvz9POfl1UP30OffVsrLnovdLgqYDMwLuKNxgWLNrf04GGk Lcl4cuadJot48VFAaq3jS/m9eYZjHGXePZ0amaK1JktsOq3pMuEjeZN/vubEPHX7ZuCNieCM 14/4F56SGT+bV9q7jdMpSYWyo8cHj92sEOjW08YWj76UuiwzGDIfsn/0uzxH/SopXJtcmbKd qP7jXE1nfzKhc9gix6X5aIH0yDEByohFwhCWihH9CwmGeIWVBAAA X-Brightmail-Tracker: H4sIAAAAAAAAA02SfUhTYRTGe++9u/c6Wt2my9eKglVURqtByJvZB1R6Q4miKChKV7up6Nba dX2IpLagmpRl6GpqmpjiBopOs1qWrSxsibOFTmuWH2FlpmZRyz7nCvzvx3me5zznj0Pj4tfE LDpRncJp1YpkKSkkbjyQzlu2Sec+uML4LAQ5Ky0AWTzZJBp88AmgvBEvjn57BjDU2XgLQxWW JgzlG/UY6q8y4ag6m0Z9L8co5C0zUyjH3g5QQ9dS9KwkCt1paCZQUdkbCmV13CRR+eNfGKoc HCZQq6mAWi9hXc+j2VsmD8W2dlcTbF7OE5J1tejYGvNZkrWWprO24jGMtXVmkOzomy6CPV9r BuzT4ocUO1Yzd6totzBCySUnHuG0y9fGCRNKzzUKNO2iY8MmB5UBvEIDCKAhsxIa7d8EBiCk xYwNwAbLEPALwVDf/o3ycyCs+DVA+U2DAL7/XkL4BBGzFnqzSjEfE8wCOKqvIP3zGbD5Sv+E R8Lsh3deZU54AplV0N4yJPAx/regq79oYh7EhMKTJaOYrwBnThEwx/0B+Nt+AHjdmocbAE2T zBLovKTzBQKYjXDcmg/8i8Kgoc7wj+fB+qEC/AIQmybdYZrUZ5oUMU2KFAPCDEI4Da+KV/Fy jVzNHZXxChWvU8fLDhxS1YCJJwhdchPUm0dkdoDRwA4gjUuDRINB7oNikVJxPJXTHorV6pI5 3g5m04Q0WBT89pxSzMQrUrgkjtNw2v8qRgfMysCqe2tdsUXpIRG32zq2P9m7hVg4jM/cU5f/ YqSAbw3sHs09XaHMSx2XGLqd5Wme9A5bHAqumytI3loVkdiWVt4bHv6ZkU8p5GXrbs+Rvj9l bUtyhCo2riiINTocmS/LUmZ2ZjkCjx/uK3Qr+/L3/6RrW5oGUmOqOu/NftrWWuy0hGfre6bm bvsJG5qiKunp042wzpzpuh81vu/utU3yMG/KvmnubEnMaiqs0XC954dG4tx2JGDDu2jiBHkt 4Wjkh8j1MfMvZ3icqp5HH/HwpLfrdgltO3ecWdT7pVym33zP+jVy+buuV2sWH96hXnqsPlJg i84dm9bc7Sq9mhYH0i5SUoJPUMhDcS2v+AN9Se0qcwMAAA== X-CMS-MailID: 20240904145709epcas5p1500f0810833c70c779c5b5d911fa7842 X-Msg-Generator: CA Content-Type: text/plain; charset="utf-8" CMS-TYPE: 105P DLP-Filter: Pass X-CFilter-Loop: Reflected X-CMS-RootMailID: 20240826171409epcas5p306ba210a9815e202556778a4c105b440 References: <20240826170606.255718-1-joshi.k@samsung.com> <20a9df07-f49e-ee58-3d0b-b0209e29c6af@samsung.com> <20240903-erfassen-bandmitglieder-32dfaeee66b2@brauner> On 9/3/2024 8:05 PM, Christian Brauner wrote: > On Tue, Sep 03, 2024 at 07:58:46PM GMT, Kanchan Joshi wrote: >> Hi Amir, >> >> >> On 8/26/2024 10:36 PM, Kanchan Joshi wrote: >>> Current write-hint infrastructure supports 6 temperature-based data life >>> hints. >>> The series extends the infrastructure with a new temperature-agnostic >>> placement-type hint. New fcntl codes F_{SET/GET}_RW_HINT_EX allow to >>> send the hint type/value on file. See patch #3 commit description for >>> the details. >>> >>> Overall this creates 128 placement hint values [*] that users can pass. >>> Patch #5 adds the ability to map these new hint values to nvme-specific >>> placement-identifiers. >>> Patch #4 restricts SCSI to use only life hint values. >>> Patch #1 and #2 are simple prep patches. >>> >>> [*] While the user-interface can support more, this limit is due to the >>> in-kernel plumbing consideration of the inode size. Pahole showed 32-bit >>> hole in the inode, but the code had this comment too: >>> >>> /* 32-bit hole reserved for expanding i_fsnotify_mask */ >>> >>> Not must, but it will be good to know if a byte (or two) can be used >>> here. >> >> Since having one extra byte will simplify things, I can't help but ask - >> do you still have the plans to use this space (in entirety) within inode? > > I just freed up 8 bytes in struct inode with what's currently in -next. > There will be no using up those 8 bytes unless it's for a good reason > and something that is very widely useful. I see, so now there are two holes. Seems the plan is to co-locate these and reduce the size by 8 bytes. Thanks for the pointer. Primary reason is a bit cleaner plumbing, but I'll manage without extra space.