Re: about TRIM/DISCARD support and barriers

Tejun Heo
2008-11-23T07:12:18Z

Hello,

cc'ing Matthew whom I forgot to cc in the first message. Matthew, the
original message is...

http://lkml.org/lkml/2008/11/22/260

Tejun Heo wrote:
> Dongjun Shin who works for Samsung SSD dep asked me about libata TRIM
> support and pointed me to the new DISCARD support David Woodhouse got
> merged for 2.6.28. I took a look at the code and blk-layer
> interface-wise we seemed to be ready both for filesystems and userland
> (so that fsck or something which runs background can mark unused
> blocks) but there doesn't seem to be any low level driver which
> actually implements ->prepare_discard_fn or fs which sets the DISCARD
> flag.

Dongjun, the only doc I can find about ATA TRIM is the following one.

http://t13.org/Documents/UploadedDocuments/docs2007/e07154r3-Data_Set_Management_Proposal_for_ATA-ACS2.pdf

And AFAICS this hasn't made into ACS yet. Is this what you guys are
gonna implement and Windows7 is gonna use?

Thanks.

--
tejun