diff mbox series

[v2,03/24] selftests/resctrl: Move resctrl FS mount/umount to higher level

Message ID 20230418114506.46788-4-ilpo.jarvinen@linux.intel.com
State New
Headers
Series selftests/resctrl: Fixes, cleanups, and rewritten CAT test |

Commit Message

Ilpo Järvinen April 18, 2023, 11:44 a.m. UTC 
  A few places currently lack umounting resctrl FS on error paths.

Each and every test does require resctrl FS to be present already for
feature check. Thus, it makes sense to just mount it on higher level in
resctrl_tests.c.

Move resctrl FS mount/unmount into each test function in
resctrl_tests.c. Make feature validation to simply check that resctrl
FS is mounted.

Fixes: 790bf585b0ee ("selftests/resctrl: Add Cache Allocation Technology (CAT) selftest")
Fixes: 78941183d1b1 ("selftests/resctrl: Add Cache QoS Monitoring (CQM) selftest")
Fixes: f1dd71982d19 ("selftests/resctrl: Skip the test if requested resctrl feature is not supported")
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
---
 tools/testing/selftests/resctrl/cat_test.c    |  6 ---
 tools/testing/selftests/resctrl/cmt_test.c    |  4 --
 .../testing/selftests/resctrl/resctrl_tests.c | 48 ++++++++++++++++---
 tools/testing/selftests/resctrl/resctrl_val.c |  5 --
 tools/testing/selftests/resctrl/resctrlfs.c   |  7 ++-
 5 files changed, 47 insertions(+), 23 deletions(-)

Comments

Reinette Chatre April 22, 2023, 12:09 a.m. UTC | #1 
Hi Ilpo,

On 4/18/2023 4:44 AM, Ilpo Järvinen wrote:
> A few places currently lack umounting resctrl FS on error paths.

You mention "A few places" (plural). In the patch I do see that
cmt_resctrl_val() is missing an unmount. Where are the other places?

> Each and every test does require resctrl FS to be present already for
> feature check. Thus, it makes sense to just mount it on higher level in
> resctrl_tests.c.
> 
> Move resctrl FS mount/unmount into each test function in
> resctrl_tests.c. Make feature validation to simply check that resctrl
> FS is mounted.
> 

...

> diff --git a/tools/testing/selftests/resctrl/cmt_test.c b/tools/testing/selftests/resctrl/cmt_test.c
> index af71b2141271..426d11189a99 100644
> --- a/tools/testing/selftests/resctrl/cmt_test.c
> +++ b/tools/testing/selftests/resctrl/cmt_test.c
> @@ -86,10 +86,6 @@ int cmt_resctrl_val(int cpu_no, int n, char **benchmark_cmd)
>  
>  	cache_size = 0;
>  
> -	ret = remount_resctrlfs(true);
> -	if (ret)
> -		return ret;
> -
>  	if (!validate_resctrl_feature_request(CMT_STR))
>  		return -1;
>  
> diff --git a/tools/testing/selftests/resctrl/resctrl_tests.c b/tools/testing/selftests/resctrl/resctrl_tests.c
> index 9b9751206e1c..5c9ed52b69f2 100644
> --- a/tools/testing/selftests/resctrl/resctrl_tests.c
> +++ b/tools/testing/selftests/resctrl/resctrl_tests.c
> @@ -77,9 +77,15 @@ static void run_mbm_test(bool has_ben, char **benchmark_cmd, int span,
>  
>  	ksft_print_msg("Starting MBM BW change ...\n");
>  
> +	res = remount_resctrlfs(false);

I think that should be remount_resctrlfs(true). Please note that any of the tests could be
run separately from the command line and thus each test need to ensure a clean
environment, it cannot assume that (a) user space provided it with a clean and/or
unmounted resctrl or (b) that any test was run before it.

> +	if (res) {
> +		ksft_exit_fail_msg("Failed to mount resctrl FS\n");
> +		return;
> +	}
> +
>  	if (!validate_resctrl_feature_request(MBM_STR) || (get_vendor() != ARCH_INTEL)) {
>  		ksft_test_result_skip("Hardware does not support MBM or MBM is disabled\n");
> -		return;
> +		goto umount;
>  	}
>  

Reinette
Ilpo Järvinen April 24, 2023, 2:58 p.m. UTC | #2 
On Fri, 21 Apr 2023, Reinette Chatre wrote:
> On 4/18/2023 4:44 AM, Ilpo Järvinen wrote:
> > A few places currently lack umounting resctrl FS on error paths.
> 
> You mention "A few places" (plural). In the patch I do see that
> cmt_resctrl_val() is missing an unmount. Where are the other places?

- cmt_resctrl_val() has multiple error paths with direct return.
- cat_perf_miss_val() has multiple error paths with direct return.

In addition, validate_resctrl_feature_request() is called by 
run_mbm_test() and run_mba_test(). Neither MBA nor MBM test tries to 
umount resctrl FS.

I improved the changelog accordingly.

While doing this, I took a more careful look into how it can result in 
problems and I think the only way is through PARENT_EXIT() because main 
has the umount in the end (and the remounting trickery kinda seems to 
work even if it was hard to track).

Fixing the PARENT_EXIT() problem required yet another change which I add
in v3.

As the only failure I could think of is because of PARENT_EXIT(), I 
removed Fixes tags from this change and put one into the PARENT_EXIT() 
umount fix. So this change will just be part of the move towards more 
tractable resctrl FS handling, not a fix anymore.

In the end, after some reshuffling, I ended up having 5 changes related to
this:

selftests/resctrl: Remove mum_resctrlfs from struct resctrl_val_param
selftests/resctrl: Refactor remount_resctrl(bool mum_resctrlfs) to mount_resctrl()
selftests/resctrl: Move resctrl FS mount/umount to higher level
selftests/resctrl: Unmount resctrl FS before starting the first test
selftests/resctrl: Unmount resctrl FS if child fails to run benchmark

> > diff --git a/tools/testing/selftests/resctrl/cmt_test.c b/tools/testing/selftests/resctrl/cmt_test.c
> > index af71b2141271..426d11189a99 100644
> > --- a/tools/testing/selftests/resctrl/cmt_test.c
> > +++ b/tools/testing/selftests/resctrl/cmt_test.c
> > @@ -86,10 +86,6 @@ int cmt_resctrl_val(int cpu_no, int n, char **benchmark_cmd)
> >  
> >  	cache_size = 0;
> >  
> > -	ret = remount_resctrlfs(true);
> > -	if (ret)
> > -		return ret;
> > -
> >  	if (!validate_resctrl_feature_request(CMT_STR))
> >  		return -1;
> >  
> > diff --git a/tools/testing/selftests/resctrl/resctrl_tests.c b/tools/testing/selftests/resctrl/resctrl_tests.c
> > index 9b9751206e1c..5c9ed52b69f2 100644
> > --- a/tools/testing/selftests/resctrl/resctrl_tests.c
> > +++ b/tools/testing/selftests/resctrl/resctrl_tests.c
> > @@ -77,9 +77,15 @@ static void run_mbm_test(bool has_ben, char **benchmark_cmd, int span,
> >  
> >  	ksft_print_msg("Starting MBM BW change ...\n");
> >  
> > +	res = remount_resctrlfs(false);
> 
> I think that should be remount_resctrlfs(true).

> Please note that any of  the tests could be 
> run separately from the command line and thus each test need to ensure a clean
> environment, it cannot assume that (a) user space provided it with a 
> clean and/or  unmounted resctrl or (b) that any test was run before it.

I think I got tripped by the level of complexity here and trying to split 
patch to minimal parts. I was somehow thinking that 
remount_resctrlfs(false) would return error if resctrl fs is already 
mounted.

I've now changed this to pass true instead even if the argument is removed 
by the other change.
diff mbox series

Patch

diff --git a/tools/testing/selftests/resctrl/cat_test.c b/tools/testing/selftests/resctrl/cat_test.c
index 722c9cd4120d..dec3151cf888 100644
--- a/tools/testing/selftests/resctrl/cat_test.c
+++ b/tools/testing/selftests/resctrl/cat_test.c
@@ -106,10 +106,6 @@  int cat_perf_miss_val(int cpu_no, int n, char *cache_type)
 
 	cache_size = 0;
 
-	ret = remount_resctrlfs(true);
-	if (ret)
-		return ret;
-
 	/* Get default cbm mask for L3/L2 cache */
 	ret = get_cbm_mask(cache_type, cbm_mask);
 	if (ret)
@@ -227,8 +223,6 @@  int cat_perf_miss_val(int cpu_no, int n, char *cache_type)
 
 out:
 	cat_test_cleanup();
-	if (bm_pid)
-		umount_resctrlfs();
 
 	return ret;
 }
diff --git a/tools/testing/selftests/resctrl/cmt_test.c b/tools/testing/selftests/resctrl/cmt_test.c
index af71b2141271..426d11189a99 100644
--- a/tools/testing/selftests/resctrl/cmt_test.c
+++ b/tools/testing/selftests/resctrl/cmt_test.c
@@ -86,10 +86,6 @@  int cmt_resctrl_val(int cpu_no, int n, char **benchmark_cmd)
 
 	cache_size = 0;
 
-	ret = remount_resctrlfs(true);
-	if (ret)
-		return ret;
-
 	if (!validate_resctrl_feature_request(CMT_STR))
 		return -1;
 
diff --git a/tools/testing/selftests/resctrl/resctrl_tests.c b/tools/testing/selftests/resctrl/resctrl_tests.c
index 9b9751206e1c..5c9ed52b69f2 100644
--- a/tools/testing/selftests/resctrl/resctrl_tests.c
+++ b/tools/testing/selftests/resctrl/resctrl_tests.c
@@ -77,9 +77,15 @@  static void run_mbm_test(bool has_ben, char **benchmark_cmd, int span,
 
 	ksft_print_msg("Starting MBM BW change ...\n");
 
+	res = remount_resctrlfs(false);
+	if (res) {
+		ksft_exit_fail_msg("Failed to mount resctrl FS\n");
+		return;
+	}
+
 	if (!validate_resctrl_feature_request(MBM_STR) || (get_vendor() != ARCH_INTEL)) {
 		ksft_test_result_skip("Hardware does not support MBM or MBM is disabled\n");
-		return;
+		goto umount;
 	}
 
 	if (!has_ben)
@@ -88,6 +94,9 @@  static void run_mbm_test(bool has_ben, char **benchmark_cmd, int span,
 	ksft_test_result(!res, "MBM: bw change\n");
 	if ((get_vendor() == ARCH_INTEL) && res)
 		ksft_print_msg("Intel MBM may be inaccurate when Sub-NUMA Clustering is enabled. Check BIOS configuration.\n");
+
+umount:
+	umount_resctrlfs();
 }
 
 static void run_mba_test(bool has_ben, char **benchmark_cmd, int span,
@@ -97,15 +106,24 @@  static void run_mba_test(bool has_ben, char **benchmark_cmd, int span,
 
 	ksft_print_msg("Starting MBA Schemata change ...\n");
 
+	res = remount_resctrlfs(false);
+	if (res) {
+		ksft_exit_fail_msg("Failed to mount resctrl FS\n");
+		return;
+	}
+
 	if (!validate_resctrl_feature_request(MBA_STR) || (get_vendor() != ARCH_INTEL)) {
 		ksft_test_result_skip("Hardware does not support MBA or MBA is disabled\n");
-		return;
+		goto umount;
 	}
 
 	if (!has_ben)
 		sprintf(benchmark_cmd[1], "%d", span);
 	res = mba_schemata_change(cpu_no, bw_report, benchmark_cmd);
 	ksft_test_result(!res, "MBA: schemata change\n");
+
+umount:
+	umount_resctrlfs();
 }
 
 static void run_cmt_test(bool has_ben, char **benchmark_cmd, int cpu_no)
@@ -113,9 +131,16 @@  static void run_cmt_test(bool has_ben, char **benchmark_cmd, int cpu_no)
 	int res;
 
 	ksft_print_msg("Starting CMT test ...\n");
+
+	res = remount_resctrlfs(false);
+	if (res) {
+		ksft_exit_fail_msg("Failed to mount resctrl FS\n");
+		return;
+	}
+
 	if (!validate_resctrl_feature_request(CMT_STR)) {
 		ksft_test_result_skip("Hardware does not support CMT or CMT is disabled\n");
-		return;
+		goto umount;
 	}
 
 	if (!has_ben)
@@ -124,6 +149,9 @@  static void run_cmt_test(bool has_ben, char **benchmark_cmd, int cpu_no)
 	ksft_test_result(!res, "CMT: test\n");
 	if ((get_vendor() == ARCH_INTEL) && res)
 		ksft_print_msg("Intel CMT may be inaccurate when Sub-NUMA Clustering is enabled. Check BIOS configuration.\n");
+
+umount:
+	umount_resctrlfs();
 }
 
 static void run_cat_test(int cpu_no, int no_of_bits)
@@ -132,13 +160,23 @@  static void run_cat_test(int cpu_no, int no_of_bits)
 
 	ksft_print_msg("Starting CAT test ...\n");
 
+	res = remount_resctrlfs(false);
+	if (res) {
+		ksft_exit_fail_msg("Failed to mount resctrl FS\n");
+		return;
+	}
+
 	if (!validate_resctrl_feature_request(CAT_STR)) {
 		ksft_test_result_skip("Hardware does not support CAT or CAT is disabled\n");
-		return;
+		goto umount;
 	}
 
 	res = cat_perf_miss_val(cpu_no, no_of_bits, "L3");
 	ksft_test_result(!res, "CAT: test\n");
+
+
+umount:
+	umount_resctrlfs();
 }
 
 int main(int argc, char **argv)
@@ -266,7 +304,5 @@  int main(int argc, char **argv)
 	if (cat_test)
 		run_cat_test(cpu_no, no_of_bits);
 
-	umount_resctrlfs();
-
 	ksft_finished();
 }
diff --git a/tools/testing/selftests/resctrl/resctrl_val.c b/tools/testing/selftests/resctrl/resctrl_val.c
index ab1eab1e7ff6..e8f1e6a59f4a 100644
--- a/tools/testing/selftests/resctrl/resctrl_val.c
+++ b/tools/testing/selftests/resctrl/resctrl_val.c
@@ -648,10 +648,6 @@  int resctrl_val(char **benchmark_cmd, struct resctrl_val_param *param)
 			return ret;
 	}
 
-	ret = remount_resctrlfs(param->mum_resctrlfs);
-	if (ret)
-		return ret;
-
 	/*
 	 * If benchmark wasn't successfully started by child, then child should
 	 * kill parent, so save parent's pid
@@ -788,7 +784,6 @@  int resctrl_val(char **benchmark_cmd, struct resctrl_val_param *param)
 	signal_handler_unregister();
 out:
 	kill(bm_pid, SIGKILL);
-	umount_resctrlfs();
 
 	return ret;
 }
diff --git a/tools/testing/selftests/resctrl/resctrlfs.c b/tools/testing/selftests/resctrl/resctrlfs.c
index fb00245dee92..42f547a81e25 100644
--- a/tools/testing/selftests/resctrl/resctrlfs.c
+++ b/tools/testing/selftests/resctrl/resctrlfs.c
@@ -611,7 +611,8 @@  char *fgrep(FILE *inf, const char *str)
  * validate_resctrl_feature_request - Check if requested feature is valid.
  * @resctrl_val:	Requested feature
  *
- * Return: True if the feature is supported, else false
+ * Return: True if the feature is supported, else false. False is also
+ *	   returned if resctrl FS is not mounted.
  */
 bool validate_resctrl_feature_request(const char *resctrl_val)
 {
@@ -619,11 +620,13 @@  bool validate_resctrl_feature_request(const char *resctrl_val)
 	bool found = false;
 	char *res;
 	FILE *inf;
+	int ret;
 
 	if (!resctrl_val)
 		return false;
 
-	if (remount_resctrlfs(false))
+	ret = find_resctrl_mount(NULL);
+	if (ret)
 		return false;
 
 	if (!strncmp(resctrl_val, CAT_STR, sizeof(CAT_STR))) {