Merge pull request #25285 from johnteslade:cgroupsv2-support

asmorkalov · web-flow · commit 9f123f8d748a · 2024-03-30T11:26:23.000+03:00
core: Add cgroupsv2 support to parallel.cpp
diff --git a/modules/core/src/parallel.cpp b/modules/core/src/parallel.cpp
@@ -870,7 +870,22 @@ int getNumberOfCPUsImpl(const char *filename)
 
 #if defined CV_HAVE_CGROUPS
 static inline
-unsigned getNumberOfCPUsCFS()
+unsigned getNumberOfCPUsCFSv2()
+{
+    int cfs_quota = 0;
+    int cfs_period = 0;
+
+    std::ifstream ss_cpu_max("/sys/fs/cgroup/cpu.max", std::ios::in | std::ios::binary);
+    ss_cpu_max >> cfs_quota >> cfs_period;
+
+    if (ss_cpu_max.fail() || cfs_quota < 1 || cfs_period < 1) /* values must not be 0 or negative */
+        return 0;
+
+    return (unsigned)max(1, cfs_quota/cfs_period);
+}
+
+static inline
+unsigned getNumberOfCPUsCFSv1()
 {
     int cfs_quota = 0;
     {
@@ -966,8 +981,11 @@ int getNumberOfCPUs_()
     static unsigned ncpus_impl_cpuset = (unsigned)getNumberOfCPUsImpl("/sys/fs/cgroup/cpuset/cpuset.cpus");
     ncpus = minNonZero(ncpus, ncpus_impl_cpuset);
 
-    static unsigned ncpus_impl_cfs = getNumberOfCPUsCFS();
-    ncpus = minNonZero(ncpus, ncpus_impl_cfs);
+    static unsigned ncpus_impl_cfs_v1 = getNumberOfCPUsCFSv1();
+    ncpus = minNonZero(ncpus, ncpus_impl_cfs_v1);
+
+    static unsigned ncpus_impl_cfs_v2 = getNumberOfCPUsCFSv2();
+    ncpus = minNonZero(ncpus, ncpus_impl_cfs_v2);
 #endif
 
     static unsigned ncpus_impl_devices = (unsigned)getNumberOfCPUsImpl("/sys/devices/system/cpu/online");
