Re: Working on Discard for FFS

[christos%astron.com@localhost (Christos Zoulas)]

In article <102k6l5$u8i$1%ciao.gmane.io@localhost>,
Christos Zoulas <christos%astron.com@localhost> wrote:
>In article <CAO5QJJVT65VAy7rsqK8jGCj_h8ipwyMYD5dkukO8cgV+RsjUoQ%mail.gmail.com@localhost>,
>Joshua Gillett  <joshuagillett%college.harvard.edu@localhost> wrote:
>>-=-=-=-=-=-
>>
>>tech-kern,
>>
>>I wanted to follow up. Iâ??m interesting in doing some work on this and
>>wanted to know the feasibility of and if there was any more information
>>pertaining to the project.
>>
>>Best wishes,
>>Joshua Gillett
>>Harvard College â??27
>>A.B. Candidate in Computer Science
>
>Hi Joshua,
>
>There is some low level support in NetBSD for trim in the device drivers
>(wd for example), but there is no ioctl interface, filesystem support and
>of course no userland trim utility. I would check out how FreeBSD does it
>first and model it after that. I would start with ioctl support, then
>userland utility support to test and finally I would start adding support
>to ffs. I think that we would need to update our zfs code to support trim.

And of course Greg is right, there is fdiscard(2) I missed that. There is
also a long discussion about fdiscard and the ioctl approach in this group,
so I would start by reading that.

christos