Re: [RFC PATCH 00/20] Introduce the famfs shared-memory file system

From: Miklos Szeredi
Date: Fri May 24 2024 - 03:56:17 EST


On Fri, 24 May 2024 at 02:47, John Groves <John@xxxxxxxxxx> wrote:

> Apologies, but I'm short on time at the moment - going into a long holiday
> weekend in the US with family plans. I should be focused again by middle of
> next week.

NP.

Obviously I'll need to test it before anything is merged, other than
that this is not urgent at all...

> But can you check /proc/cmdline to see of the memmap arg got through without
> getting mangled? The '$' tends to get fubar'd. You might need \$, or I've seen
> the need for \\\$. If it's un-mangled, there should be a dax device.

/proc/cmdline shows the option correctly:

root@kvm:~# cat /proc/cmdline
root=/dev/vda console=hvc0 memmap=4G$4G

> If that doesn't work, it's worth trying '!' instead, which I think would give
> you a pmem device - if the arg gets through (but ! is less likely to get
> horked). That pmem device can be converted to devdax...

That doesn't work either. No device created in /dev (dax or pmem).

free(1) does show that the reserved memory is gone in both cases, so
something does happen.

Attaching my .config as well.

Thanks,
Miklos

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