I think James will need to comment on this, but I think that yes, itif "resctrl" is nonfunctional in this state, then this comment[1] here does
is probably appropriate to require a reboot. I think an MPAM error
interrupt should only happen if the software did something wrong, so
it's a bit like hitting a BUG(): we don't promise that everything works
100% properly until the system is restarted. Misbehaviour should be
contained to MPAM though.
*not* make sense.
"restore any modified controls to their reset values."
Can you clarify what you mean here?
I think it makes sense to clean up the MPAM hardware as well as we can
in these situations, even if we can't be certain what went wrong.
[final comments below]
Thanks
-Amit
[1]: https://urldefense.proofpoint.com/v2/url?u=https-3A__git.kernel.org_pub_scm_linux_kernel_git_morse_linux.git_tree_drivers_platform_mpam_mpam-5Fdevices.c-3Fh-3Dmpam_snapshot_v6.7-2Drc2-23n2228&d=DwIBAg&c=nKjWec2b6R0mOyPaz7xtfQ&r=V_GK7jRuCHDErm6txmgDK1-MbUihtnSQ3gPgB-A-JKU&m=DzR4EYX-356bYvqcrD5mYQBzLmDppMaRaHx6yjN7nRE5GH7nogtw6VtDZchmqb_q&s=SKpVy4sPg3dbFJGfMfUGoo252IHOrHrLfcv5f0sCmm0&e=
root@localhost:~# mount
tmpfs on /run/user/0 type tmpfs
(rw,nosuid,nodev,relatime,size=32923772k,nr_inodes=8230943,mode=700)
resctrl on /sys/fs/resctrl type resctrl (rw,relatime)
root@localhost:~# devmem msc_addr 32 0x9999
[ 687.096276] mpam: error irq from msc:1 'PARTID_SEL_Range', partid:39321,
pmg: 0, ris: 0
root@localhost:~# mount
tmpfs on /run/user/0 type tmpfs
(rw,nosuid,nodev,relatime,size=32923772k,nr_inodes=8230943,mode=700)
resctrl on /sys/fs/resctrl type resctrl (rw,relatime)
root@localhost:~# umount resctrl
umount: /sys/fs/resctrl: no mount point specified.
root@localhost:~# mount
tmpfs on /run/user/0 type tmpfs
(rw,nosuid,nodev,relatime,size=32923772k,nr_inodes=8230943,mode=700)
root@localhost:~# mount -t resctrl resctrl /test
mount: /test: unknown filesystem type 'resctrl'.
Thanks for trying this out.
I guess the behaviour here might want a bit more thought.
I'm not too keen on us leaving a defective mount in the namespace,
with a nonexistent mount pount. I'm wondering whether things like
systemd may get confused by this...
Cheers
---Dave