[dm-devel] Revert "dm space maps: don't reset space map allocation cursor when committing"

[Edward Thornber]

I'm having trouble understanding your issue.  Does your ramdisk only
allocate backing memory on demand?  (ie. is the ramdisk itself a thinly
provisioned device?).  If so, not supporting discard seems to be the
problem.

Thinp makes no promises about where it will allocate your data.  If you
write a file, delete it, discard and then rewrite the file there is no
guarantee that the file will be written to the same location.

On Tue, Mar 1, 2022 at 2:08 PM luomeng <luomeng12 at huawei.com> wrote:

> Because thin-pool is storage over-commitment, one of the following
> scenarios exists: constantly create and delete file, then the search
> doesn't hit the end of the metadata device, but ramdisk hits the end
> (not support discard). So the cursor doesn't reset.
>
> 在 2022/2/28 23:37, Mike Snitzer 写道:
> > What you're saying doesn't make any sense.  Especially when you
> > consider this last part of the commit message:
> > "Fix these issues by leaving the cursor alone, only resetting when the
> >   search hits the end of the metadata device."
>
>
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