linux-kernel - Re: [PATCH v6 0/5] selftests/resctrl: Add non-contiguous CBMs in Intel CAT selftest

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Date: Fri, 23 Feb 2024 15:11:11 -0800
From: Reinette Chatre <reinette.chatre@...el.com>
To: Shuah Khan <skhan@...uxfoundation.org>, Maciej Wieczor-Retman
	<maciej.wieczor-retman@...el.com>, <shuah@...nel.org>, <fenghua.yu@...el.com>
CC: <linux-kselftest@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
	<ilpo.jarvinen@...ux.intel.com>
Subject: Re: [PATCH v6 0/5] selftests/resctrl: Add non-contiguous CBMs in
 Intel CAT selftest

Hi Shuah,

On 2/23/2024 2:37 PM, Shuah Khan wrote:
> Okay ran a quick test. Why does this test leave "/sys/fs/resctrl"
> mounted when it exits. Can we fix this to unmount before the test
> exits?

This is unexpected. The test should unmount resctrl when done and I am
not able to reproduce what you are seeing. I tried with resctrl mounted
as well as unmounted before the test run. Could you please send the output
of your test run to hopefully get some hints about what is going on?

Please do note that resctrl does create the mountpoint upon initialization
so you should always, for example, see /sys/fs/resctrl, but it should
be unmounted and empty after a test run.

Below is what I am seeing when I try latest from kselftest next and mount
resctrl before the test. I see same state after test if I do not mount
resctrl before the test run.

./dev/linux$ mount | grep resctrl #not mounted
./dev/linux$ ls /sys/fs/resctrl/  #empty
./dev/linux$ sudo mount -t resctrl resctrl /sys/fs/resctrl/
./dev/linux$ ls /sys/fs/resctrl/  #has contents after mount
cpus  cpus_list  info  mode  mon_data  mon_groups  schemata  size  tasks
./dev/linux$ mount | grep resctrl #shows as mounted 
resctrl on /sys/fs/resctrl type resctrl (rw,relatime)
./dev/linux$ git show -s --pretty='format:%h (\"%s\")'
ae638551ab64 (\"selftests/resctrl: Add non-contiguous CBMs CAT test\")
./dev/linux$ make -C tools/testing/selftests/resctrl/
make: Entering directory '/home/reinette/dev/linux/tools/testing/selftests/resctrl'
gcc -g -Wall -O2 -D_FORTIFY_SOURCE=2 -D_GNU_SOURCE -isystem /home/reinette/dev/linux/tools/testing/selftests/../../../usr/include     resctrl_tests.c cache.c cat_test.c cmt_test.c fill_buf.c mba_test.c mbm_test.c resctrlfs.c resctrl.h resctrl_val.c  -o /home/reinette/dev/linux/tools/testing/selftests/resctrl/resctrl_tests
make: Leaving directory '/home/reinette/dev/linux/tools/testing/selftests/resctrl'
./dev/linux$ sudo ./tools/testing/selftests/resctrl/resctrl_tests
[SNIP]
./dev/linux$ mount | grep resctrl #umounted after test run
./dev/linux$ ls /sys/fs/resctrl/  #empty
./dev/linux$ 

> 
> Please send a patch on top of linux-kselftest next.

Will do, as soon as I can figure out what is going on.

Reinette