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From: Eric Sandeen <>
To: Christoph Hellwig <>
Cc: Chaitanya Kulkarni <>,
	Pavel Reichl <>,
	"" <>
Subject: Re: [PATCH v3] mkfs: Break block discard into chunks of 2 GB
Date: Wed, 4 Dec 2019 11:32:02 -0600
Message-ID: <> (raw)
In-Reply-To: <>

On 12/4/19 11:26 AM, Christoph Hellwig wrote:
> On Wed, Dec 04, 2019 at 10:24:32AM -0600, Eric Sandeen wrote:
>> It'd be great to fix this universally in the kernel but it seems like
>> that patch is in discussion for now, and TBH I don't see any real
>> drawbacks to looping in mkfs - it would also solve the problem on any
>> old kernel w/o the block layer change.
> The problem is that we throw out efficiency for no good reason.

The reason, as I stated earlier, is that up to this day, no kernel properly
handles this, and people are hitting this problem today.

And nobody has shown a significant efficiency loss.  (To be fair, nobody
has shown that there isn't a loss either, but in my admittedly small
test set I didn't see any meaningful overhead from the loop.)

>> I'd propose that we go ahead w/ the mkfs change, and if/when the kernel
>> handles this better, and it's reasonable to expect that we're running
>> on a kernel where it can be interrupted, we could remove the mkfs loop
>> at a later date if we wanted to.
> I'd rather not touch mkfs if a trivial kernel patch handles the issue.

I don't think a trivial kernel patch to handle the issue even exists yet...


  reply index

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-28  6:21 Pavel Reichl
2019-11-30 22:01 ` Chaitanya Kulkarni
2019-12-02 16:40   ` Darrick J. Wong
2019-12-04 16:24   ` Eric Sandeen
2019-12-04 17:26     ` Christoph Hellwig
2019-12-04 17:32       ` Eric Sandeen [this message]
2019-12-04 17:42       ` Darrick J. Wong
2019-12-10  7:33         ` Chaitanya Kulkarni
2019-12-10 14:20           ` Eric Sandeen
2019-12-09 22:00 ` Eric Sandeen
2019-12-09 23:34   ` Darrick J. Wong
2019-12-10  0:49     ` Eric Sandeen

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