[dm-devel] [RFC 1/2] block: implement an unprep function corresponding directly to prep

[Jeff Garzik]

On 07/05/2010 05:54 PM, Mark Lord wrote:
>> On 05/07/10 03:24 PM, Christoph Hellwig wrote:
>>>
>>> What codebase were you testing on? Sorry, but curently I'm a bit lost
>>> in the maze of patches. I've got both and intel and an OCZ SSD
> ..
>
> Do you, or anyone else with one, know what the upper limit is on
> TRIM operations with the Intel SSDs ?
>
> I need to know the maximum amount of TRIM ranges they will process
> in a single command.
>
> Eg. Indilinx-based SSDs don't appear to have a limit -- they'll accept
> a TRIM command with thousands of LBA ranges included.
>
> Sandforce-based SSDs appear to restrict things to max 4KB of range data.
>
> So.. what about Intel?

Lovely :(  I wonder if we could test for that limit at mke2fs time, or 
similar.

Seeing a 4k limit on other SSDs would not surprise me.  Or even a 512-b 
limit.

	Jeff