From: "Javier González" <javier.gonz@samsung.com> To: Christoph Hellwig <hch@lst.de> Cc: Pankaj Raghav <p.raghav@samsung.com>, <axboe@kernel.dk>, <damien.lemoal@opensource.wdc.com>, <pankydev8@gmail.com>, <dsterba@suse.com>, <linux-nvme@lists.infradead.org>, <linux-fsdevel@vger.kernel.org>, <linux-btrfs@vger.kernel.org>, <jiangbo.365@bytedance.com>, <linux-block@vger.kernel.org>, <gost.dev@samsung.com>, <linux-kernel@vger.kernel.org>, <dm-devel@redhat.com> Subject: Re: [PATCH v4 00/13] support non power of 2 zoned devices Date: Tue, 17 May 2022 11:18:34 +0200 [thread overview] Message-ID: <20220517091834.dvkrab5l63v3b2zn@ArmHalley.local> (raw) In-Reply-To: <20220517081048.GA13947@lst.de> On 17.05.2022 10:10, Christoph Hellwig wrote: >I'm a little surprised about all this activity. > >I though the conclusion at LSF/MM was that for Linux itself there >is very little benefit in supporting this scheme. It will massively >fragment the supported based of devices and applications, while only >having the benefit of supporting some Samsung legacy devices. I believed we had agreed that non-power-of-2 zoned devices was something to explore. Let me summarize the 3 main points we covered at different times at LSF/MM: - This is not for legacy Samsung ZNS devices. At least 4 other vendors have reported building non-power-of-2 ZNS devices to meet customer demands on removing holes in the address space. It seems like there will be more ZNS devices with size=capacity out there than with PO2 sizes. Block device and FS support is very desirable for these. - We also talked about how the capacity not being a PO2 is the one introducing the fragmentation, as applications that already worked with SMR HDDs will have to change their data placement policy. The size is just a construction, but the real work is adopting the capacity. - Besides the previous poit, the fragmentation will happen from the moment we have available devices. This is not a kernel-only issue. We have SMR, ZNS, and soon another spec for zone devices. I understood that as long as we do not break any existing support, we would be able to expend the zoned ecosystem in Linux. >So my impression was that this work, while technically feasible, is >rather useless. So unless I missed something important I have no >interest in supporting this in NVMe. Does the above help you reconsidering your interest in supporting this in NVMe?
WARNING: multiple messages have this Message-ID (diff)
From: "Javier González" <javier.gonz@samsung.com> To: Christoph Hellwig <hch@lst.de> Cc: Pankaj Raghav <p.raghav@samsung.com>, axboe@kernel.dk, pankydev8@gmail.com, gost.dev@samsung.com, damien.lemoal@opensource.wdc.com, jiangbo.365@bytedance.com, linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org, linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org, dm-devel@redhat.com, dsterba@suse.com, linux-btrfs@vger.kernel.org Subject: Re: [dm-devel] [PATCH v4 00/13] support non power of 2 zoned devices Date: Tue, 17 May 2022 11:18:34 +0200 [thread overview] Message-ID: <20220517091834.dvkrab5l63v3b2zn@ArmHalley.local> (raw) In-Reply-To: <20220517081048.GA13947@lst.de> On 17.05.2022 10:10, Christoph Hellwig wrote: >I'm a little surprised about all this activity. > >I though the conclusion at LSF/MM was that for Linux itself there >is very little benefit in supporting this scheme. It will massively >fragment the supported based of devices and applications, while only >having the benefit of supporting some Samsung legacy devices. I believed we had agreed that non-power-of-2 zoned devices was something to explore. Let me summarize the 3 main points we covered at different times at LSF/MM: - This is not for legacy Samsung ZNS devices. At least 4 other vendors have reported building non-power-of-2 ZNS devices to meet customer demands on removing holes in the address space. It seems like there will be more ZNS devices with size=capacity out there than with PO2 sizes. Block device and FS support is very desirable for these. - We also talked about how the capacity not being a PO2 is the one introducing the fragmentation, as applications that already worked with SMR HDDs will have to change their data placement policy. The size is just a construction, but the real work is adopting the capacity. - Besides the previous poit, the fragmentation will happen from the moment we have available devices. This is not a kernel-only issue. We have SMR, ZNS, and soon another spec for zone devices. I understood that as long as we do not break any existing support, we would be able to expend the zoned ecosystem in Linux. >So my impression was that this work, while technically feasible, is >rather useless. So unless I missed something important I have no >interest in supporting this in NVMe. Does the above help you reconsidering your interest in supporting this in NVMe? -- dm-devel mailing list dm-devel@redhat.com https://listman.redhat.com/mailman/listinfo/dm-devel
next prev parent reply other threads:[~2022-05-17 9:19 UTC|newest] Thread overview: 109+ messages / expand[flat|nested] mbox.gz Atom feed top [not found] <CGME20220516165418eucas1p2be592d9cd4b35f6b71d39ccbe87f3fef@eucas1p2.samsung.com> 2022-05-16 16:54 ` [PATCH v4 00/13] support non power of 2 zoned devices Pankaj Raghav 2022-05-16 16:54 ` [dm-devel] " Pankaj Raghav [not found] ` <CGME20220516165419eucas1p104aadda60df323e6154bfc3b92103b7b@eucas1p1.samsung.com> 2022-05-16 16:54 ` [PATCH v4 01/13] block: make blkdev_nr_zones and blk_queue_zone_no generic for npo2 zsze Pankaj Raghav 2022-05-16 16:54 ` [dm-devel] " Pankaj Raghav [not found] ` <CGME20220516165421eucas1p2515446ac290987bdb9af24ffb835b287@eucas1p2.samsung.com> 2022-05-16 16:54 ` [PATCH v4 02/13] block: allow blk-zoned devices to have non-power-of-2 zone size Pankaj Raghav 2022-05-16 16:54 ` [dm-devel] " Pankaj Raghav 2022-05-16 19:05 ` Pankaj Raghav 2022-05-16 19:05 ` [dm-devel] " Pankaj Raghav [not found] ` <CGME20220516165422eucas1p174acec28848a9c2178376f092af3fa1c@eucas1p1.samsung.com> 2022-05-16 16:54 ` [PATCH v4 03/13] nvme: zns: Allow ZNS drives that have non-power_of_2 " Pankaj Raghav 2022-05-16 16:54 ` [dm-devel] " Pankaj Raghav [not found] ` <CGME20220516165424eucas1p2ee38cd64260539e5cac8d1fa4d0cba38@eucas1p2.samsung.com> 2022-05-16 16:54 ` [PATCH v4 04/13] nvmet: Allow ZNS target to support non-power_of_2 zone sizes Pankaj Raghav 2022-05-16 16:54 ` [dm-devel] " Pankaj Raghav 2022-05-17 14:19 ` Johannes Thumshirn 2022-05-17 14:19 ` [dm-devel] " Johannes Thumshirn [not found] ` <CGME20220516165425eucas1p29fcd11d7051d9d3a9a9efc17cd3b6999@eucas1p2.samsung.com> 2022-05-16 16:54 ` [PATCH v4 05/13] btrfs: zoned: Cache superblock location in btrfs_zoned_device_info Pankaj Raghav 2022-05-16 16:54 ` [dm-devel] " Pankaj Raghav 2022-05-16 21:58 ` David Sterba 2022-05-16 21:58 ` [dm-devel] " David Sterba 2022-05-17 7:55 ` Pankaj Raghav 2022-05-17 7:55 ` [dm-devel] " Pankaj Raghav [not found] ` <CGME20220516165427eucas1p1cfd87ca44ec314ea1d2ddc8ece7259f9@eucas1p1.samsung.com> 2022-05-16 16:54 ` [PATCH v4 06/13] btrfs: zoned: Make sb_zone_number function non power of 2 compatible Pankaj Raghav 2022-05-16 16:54 ` [dm-devel] " Pankaj Raghav 2022-05-17 6:53 ` Johannes Thumshirn 2022-05-17 6:53 ` [dm-devel] " Johannes Thumshirn 2022-05-17 11:51 ` David Sterba 2022-05-17 11:51 ` [dm-devel] " David Sterba [not found] ` <CGME20220516165428eucas1p1374b5f9592db3ca6a6551aff975537ce@eucas1p1.samsung.com> 2022-05-16 16:54 ` [PATCH v4 07/13] btrfs: zoned: use generic btrfs zone helpers to support npo2 zoned devices Pankaj Raghav 2022-05-16 16:54 ` [dm-devel] " Pankaj Raghav 2022-05-17 12:30 ` David Sterba 2022-05-17 12:30 ` [dm-devel] " David Sterba 2022-05-18 9:40 ` Pankaj Raghav 2022-05-18 9:40 ` Pankaj Raghav 2022-05-18 11:21 ` David Sterba 2022-05-18 11:21 ` [dm-devel] " David Sterba 2022-05-19 4:13 ` Naohiro Aota 2022-05-19 4:13 ` [dm-devel] " Naohiro Aota [not found] ` <CGME20220516165429eucas1p272c8b4325a488675f08f2d7016aa6230@eucas1p2.samsung.com> 2022-05-16 16:54 ` [PATCH v4 08/13] btrfs:zoned: make sb for npo2 zone devices align with sb log offsets Pankaj Raghav 2022-05-16 16:54 ` [dm-devel] " Pankaj Raghav 2022-05-17 6:50 ` Johannes Thumshirn 2022-05-17 6:50 ` Johannes Thumshirn 2022-05-17 8:00 ` Pankaj Raghav 2022-05-17 8:00 ` [dm-devel] " Pankaj Raghav 2022-05-17 12:42 ` David Sterba 2022-05-17 12:42 ` [dm-devel] " David Sterba 2022-05-18 9:15 ` Pankaj Raghav 2022-05-18 9:15 ` [dm-devel] " Pankaj Raghav 2022-05-19 7:57 ` Johannes Thumshirn 2022-05-19 7:57 ` [dm-devel] " Johannes Thumshirn 2022-05-20 9:06 ` Pankaj Raghav 2022-05-20 9:06 ` [dm-devel] " Pankaj Raghav 2022-05-20 9:15 ` Johannes Thumshirn 2022-05-20 9:15 ` [dm-devel] " Johannes Thumshirn 2022-05-19 7:59 ` Naohiro Aota 2022-05-19 7:59 ` [dm-devel] " Naohiro Aota 2022-05-20 9:09 ` Pankaj Raghav 2022-05-20 9:09 ` [dm-devel] " Pankaj Raghav [not found] ` <CGME20220516165430eucas1p214cca8eaba1db2c98d947444cad4f18f@eucas1p2.samsung.com> 2022-05-16 16:54 ` [PATCH v4 09/13] btrfs: zoned: relax the alignment constraint for zoned devices Pankaj Raghav 2022-05-16 16:54 ` [dm-devel] " Pankaj Raghav [not found] ` <CGME20220516165432eucas1p2e1ea74d44738e44745f49e37b6b9e503@eucas1p2.samsung.com> 2022-05-16 16:54 ` [PATCH v4 10/13] zonefs: allow non power of 2 " Pankaj Raghav 2022-05-16 16:54 ` [dm-devel] " Pankaj Raghav [not found] ` <CGME20220516165434eucas1p12b178fb83cc93470933e3d72c40e9004@eucas1p1.samsung.com> 2022-05-16 16:54 ` [PATCH v4 11/13] null_blk: " Pankaj Raghav 2022-05-16 16:54 ` [dm-devel] " Pankaj Raghav 2022-05-17 4:12 ` kernel test robot 2022-05-17 4:12 ` [dm-devel] " kernel test robot [not found] ` <CGME20220516165435eucas1p1dff8d9d039a76278ef1c09dba4b4e1fe@eucas1p1.samsung.com> 2022-05-16 16:54 ` [PATCH v4 12/13] null_blk: use zone_size_sects_shift for " Pankaj Raghav 2022-05-16 16:54 ` [dm-devel] " Pankaj Raghav [not found] ` <CGME20220516165436eucas1p178d079302dae3a9fca696b13b0390deb@eucas1p1.samsung.com> 2022-05-16 16:54 ` [dm-devel] [PATCH v4 13/13] dm-zoned: ensure only power of 2 zone sizes are allowed Pankaj Raghav 2022-05-16 16:54 ` Pankaj Raghav 2022-05-17 8:10 ` [PATCH v4 00/13] support non power of 2 zoned devices Christoph Hellwig 2022-05-17 8:10 ` [dm-devel] " Christoph Hellwig 2022-05-17 9:18 ` Javier González [this message] 2022-05-17 9:18 ` Javier González 2022-05-18 8:00 ` Christoph Hellwig 2022-05-18 8:00 ` [dm-devel] " Christoph Hellwig 2022-05-19 15:25 ` Javier González 2022-05-19 15:25 ` [dm-devel] " Javier González 2022-05-17 15:34 ` Theodore Ts'o 2022-05-17 15:34 ` Theodore Ts'o 2022-05-18 23:06 ` Luis Chamberlain 2022-05-18 23:06 ` Luis Chamberlain 2022-05-19 3:08 ` Damien Le Moal 2022-05-19 3:08 ` Damien Le Moal 2022-05-19 3:12 ` Luis Chamberlain 2022-05-19 3:12 ` Luis Chamberlain 2022-05-19 3:19 ` Damien Le Moal 2022-05-19 3:19 ` Damien Le Moal 2022-05-19 7:34 ` Johannes Thumshirn 2022-05-19 7:34 ` Johannes Thumshirn 2022-05-20 3:47 ` Damien Le Moal 2022-05-20 3:47 ` Damien Le Moal 2022-05-20 6:07 ` Hannes Reinecke 2022-05-20 6:07 ` Hannes Reinecke 2022-05-20 6:27 ` Javier González 2022-05-20 6:27 ` Javier González 2022-05-20 6:41 ` Damien Le Moal 2022-05-20 6:41 ` Damien Le Moal [not found] ` <CGME20220520065941eucas1p105cf273ede995dc4bf92f3245fad09b1@eucas1p1.samsung.com> 2022-05-20 6:59 ` Javier González 2022-05-20 6:59 ` Javier González 2022-05-20 9:30 ` Pankaj Raghav 2022-05-20 9:30 ` Pankaj Raghav 2022-05-20 17:18 ` David Sterba 2022-05-20 17:18 ` David Sterba 2022-05-23 8:25 ` Pankaj Raghav 2022-05-23 8:25 ` Pankaj Raghav 2022-05-20 9:30 ` Johannes Thumshirn 2022-05-20 9:30 ` Johannes Thumshirn [not found] ` <CGME20220520101610eucas1p1822ca6014e2a1d55ae74476f83c4de1d@eucas1p1.samsung.com> 2022-05-20 10:16 ` Javier González 2022-05-20 10:16 ` Javier González [not found] <CGME20220516133922eucas1p1c891cd1d82539b4e792acb5d1aa74444@eucas1p1.samsung.com> 2022-05-16 13:39 ` Pankaj Raghav
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