[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <b5af0cd4-033b-42d6-a147-ec8bc8956b2f@oracle.com>
Date: Wed, 14 Feb 2024 09:21:18 +0000
From: John Garry <john.g.garry@...cle.com>
To: Christoph Hellwig <hch@....de>
Cc: axboe@...nel.dk, kbusch@...nel.org, sagi@...mberg.me, jejb@...ux.ibm.com,
martin.petersen@...cle.com, djwong@...nel.org, viro@...iv.linux.org.uk,
brauner@...nel.org, dchinner@...hat.com, jack@...e.cz,
linux-block@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-nvme@...ts.infradead.org, linux-xfs@...r.kernel.org,
linux-fsdevel@...r.kernel.org, tytso@....edu, jbongio@...gle.com,
linux-scsi@...r.kernel.org, ming.lei@...hat.com, ojaswin@...ux.ibm.com,
bvanassche@....org, Alan Adamson <alan.adamson@...cle.com>
Subject: Re: [PATCH v3 14/15] nvme: Support atomic writes
On 14/02/2024 08:00, Christoph Hellwig wrote:
> On Tue, Feb 13, 2024 at 02:21:25PM +0000, John Garry wrote:
>>> Please also read through TP4098(a) and look at the MAM field.
>>
>> It's not public, AFAIK.
>
> Oracle is a member, so you can take a look at it easily. If we need
> it for Linux I can also work with the NVMe Board to release it.
What I really meant was that I prefer not to quote private TPs in public
domain. I have the doc.
>
>> And I don't think a feature which allows us to straddle boundaries is too
>> interesting really.
>
> Without MAM=1 NVMe can't support atomic writes larger than
> AWUPF/NAWUPF, which is typically set to the indirection table
> size. You're leaving a lot of potential unused with that.
>
atomic_write_unit_max would always be dictated by min of boundary and
AWUPF/NAWUPF. With MAM=1, we could increase atomic_write_max_bytes - but
does it really help us? I mean, atomic_write_max_bytes only comes into
play for merging - do we get much merging for NVMe transports? I am not
sure.
Thanks,
John
Powered by blists - more mailing lists