The CPU vendor IDs are required to be unique bits because they're used for vendor_specific bitmask in the struct resctrl_test. Consider for example their usage in test_vendor_specific_check(): return get_vendor() & test->vendor_specific
However, the definitions of CPU vendor IDs in file resctrl.h is quite subtle as a bitmask value: #define ARCH_INTEL 1 #define ARCH_AMD 2
A clearer and more maintainable approach is to define these CPU vendor IDs using BIT(). This ensures each vendor corresponds to a distinct bit and makes it obvious when adding new vendor IDs.
Accordingly, update the return types of detect_vendor() and get_vendor() from 'int' to 'unsigned int' to align with their usage as bitmask values and to prevent potentially risky type conversions.
Furthermore, introduce a bool flag 'initialized' to simplify the get_vendor() -> detect_vendor() logic. This ensures the vendor ID is detected only once and resolves the ambiguity of using the same variable 'vendor' both as a value and as a state.
Suggested-by: Reinette Chatre reinette.chatre@intel.com Suggested-by: Fenghua Yu fenghuay@nvidia.com Signed-off-by: Xiaochen Shen shenxiaochen@open-hieco.net --- tools/testing/selftests/resctrl/resctrl.h | 7 ++--- .../testing/selftests/resctrl/resctrl_tests.c | 26 +++++++++++++------ 2 files changed, 22 insertions(+), 11 deletions(-)
diff --git a/tools/testing/selftests/resctrl/resctrl.h b/tools/testing/selftests/resctrl/resctrl.h index 3c51bdac2dfa..4f9c7d04c98d 100644 --- a/tools/testing/selftests/resctrl/resctrl.h +++ b/tools/testing/selftests/resctrl/resctrl.h @@ -23,6 +23,7 @@ #include <asm/unistd.h> #include <linux/perf_event.h> #include <linux/compiler.h> +#include <linux/bits.h> #include "kselftest.h"
#define MB (1024 * 1024) @@ -36,8 +37,8 @@ * Define as bits because they're used for vendor_specific bitmask in * the struct resctrl_test. */ -#define ARCH_INTEL 1 -#define ARCH_AMD 2 +#define ARCH_INTEL BIT(0) +#define ARCH_AMD BIT(1)
#define END_OF_TESTS 1
@@ -163,7 +164,7 @@ extern int snc_unreliable; extern char llc_occup_path[1024];
int snc_nodes_per_l3_cache(void); -int get_vendor(void); +unsigned int get_vendor(void); bool check_resctrlfs_support(void); int filter_dmesg(void); int get_domain_id(const char *resource, int cpu_no, int *domain_id); diff --git a/tools/testing/selftests/resctrl/resctrl_tests.c b/tools/testing/selftests/resctrl/resctrl_tests.c index 5154ffd821c4..980ecf2bcf10 100644 --- a/tools/testing/selftests/resctrl/resctrl_tests.c +++ b/tools/testing/selftests/resctrl/resctrl_tests.c @@ -23,16 +23,24 @@ static struct resctrl_test *resctrl_tests[] = { &l2_noncont_cat_test, };
-static int detect_vendor(void) +static unsigned int detect_vendor(void) { - FILE *inf = fopen("/proc/cpuinfo", "r"); - int vendor_id = 0; + FILE *inf; + static unsigned int vendor_id; char *s = NULL; char *res; + static bool initialized;
- if (!inf) + if (initialized) return vendor_id;
+ inf = fopen("/proc/cpuinfo", "r"); + if (!inf) { + vendor_id = 0; + initialized = true; + return vendor_id; + } + res = fgrep(inf, "vendor_id");
if (res) @@ -45,15 +53,17 @@ static int detect_vendor(void)
fclose(inf); free(res); + + initialized = true; return vendor_id; }
-int get_vendor(void) +unsigned int get_vendor(void) { - static int vendor = -1; + unsigned int vendor; + + vendor = detect_vendor();
- if (vendor == -1) - vendor = detect_vendor(); if (vendor == 0) ksft_print_msg("Can not get vendor info...\n");