On Sun, Mar 7, 2010 at 12:38 PM, Martin K. Petersen <martin.petersen@xxxxxxxxxx> wrote: >>>>>> "Eric" == Eric Sandeen <sandeen@xxxxxxxxxx> writes: > > Eric> Andreas Sundstrom wrote: >>> Hi.. >>> >>> I have an OCZ agility SSD drive with FW 1.5 that supports the TRIM >>> command. >>> >>> I can see that it works on a plain partition. But it does not seem >>> to work together with LVM. >>> >>> So I'm wondering if this is expected and whether it is something that >>> will be worked on to get fixed? > > Eric> It is expected, as lvm is not yet passing discard requests. > > I'm working on this. Missed the 2.6.34 merge window so I'm aiming at > 2.6.35. Hey Martin, We've been scoping the work associated with adding discard support to DM (afaik MD would need comparable infrastructure, e.g.: spliting discard requests). There is a fair amount of complexity associated with this work. Especially when you look to support discards for some of the more advanced DM targets. Discard support for the 'linear' target is the relatively low hanging fruit. The 'striped' target gets more interesting (having to split the discard into multiple discards to submit to the appropriate underlying devices in the striped volume). One thought was we might have a block layer hook along the lines of the q->merge_bvec_fn (similar but hopefully less problematic/controversial). Christoph removed a hook that was vaguely like this, but posed allocation problems, with linux-2.6 commit: c15227de132f Please feel free to share your patches/design with dm-devel. (I'll also check with Alasdair to see about making the dm-devel filtering less prone to eat mail) Thanks! Mike -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
