[dm-devel] [PATCH v2 0/4] brd: implement discard

[Mikulas Patocka]

On Wed, 21 Sep 2022, Gao Xiang wrote:

> On Tue, Sep 20, 2022 at 01:52:38PM -0400, Mikulas Patocka wrote:
> > Hi
> > 
> > Here I'm sending second version of the brd discard patches.
> 
> That is quite interesting.
> 
> btw, something out of topic, I once had some preliminary attempt
> to add DAX support to brd since brd works as ramdisk and brd-dax
> could have the following benefits:
> 
>  - DAX can be tested without PMEM devices;
>  - ramdisk fses can be accessed without double page cache;
>  - initrd use cases then can work well without extra page cache
>    and maybe it can perform better than initramfs (without unpack
>    process).
> 
> I wrote some hack stuff but don't have more time working on it...
> https://git.kernel.org/pub/scm/linux/kernel/git/xiang/linux.git/log/?h=erofs/initrd-fsdax
> 
> I'm not sure if others are interested in topic though.
> 
> It would be helpful to get rid of all brd page->index use cases
> first.
> 
> Thanks,
> Gao Xiang

Hi

Ramdisk DAX was there in the past, but it was removed in the kernel 4.15.

Mikulas