Major number for nvidia-caps devices

Author: jblache

src/slave/containerizer/mesos/isolators/gpu/allocator.cpp

@@ -95,6 +95,11 @@ static Try<set<Gpu>> enumerateGpus(
     }
   }
 
+  Try<unsigned int> caps_major = nvml::systemGetCapsMajor();
+  if (caps_major.isError()) {
+    return Error("Failed to get nvidia caps major: " + caps_major.error());
+  }
+
   set<Gpu> gpus;
 
   foreach (unsigned int index, indices) {
@@ -148,6 +153,7 @@ static Try<set<Gpu>> enumerateGpus(
       gpu.major = NVIDIA_MAJOR_DEVICE;
       gpu.minor = minor.get();
       gpu.ismig = true;
+      gpu.caps_major = caps_major.get();
       gpu.gi_minor = gi_minor.get();
       gpu.ci_minor = ci_minor.get();
 

src/slave/containerizer/mesos/isolators/gpu/allocator.hpp

@@ -47,6 +47,7 @@ struct Gpu
 
   // MIG support
   bool ismig;
+  unsigned int caps_major;
   unsigned int gi_minor;
   unsigned int ci_minor;
 };

src/slave/containerizer/mesos/isolators/gpu/nvml.cpp

@@ -237,6 +237,30 @@ bool isAvailable()
 }
 
 
+Try<unsigned int> systemGetCapsMajor()
+{
+  std::ifstream procfile("/proc/devices");
+
+  while (procfile) {
+    string procline;
+    std::getline(procfile, procline);
+
+    if (procline.find(" nvidia-caps") != std::string::npos) {
+      unsigned int major;
+
+      try {
+	major = std::stoi(procline);
+      } catch (...) {
+	return Error("Could not parse nvidia-caps major from /proc/devices");
+      }
+
+      return major;
+    }
+  }
+  return Error("nvidia-caps not found in /proc/devices");
+}
+
+
 Try<string> systemGetDriverVersion()
 {
   if (nvml == nullptr) {

src/slave/containerizer/mesos/isolators/gpu/nvml.hpp

@@ -53,6 +53,7 @@ Try<Nothing> initialize();
 // NVML wrapper functions. May be called after initializing
 // the library.
 Try<std::string> systemGetDriverVersion();
+Try<unsigned int> systemGetCapsMajor();
 Try<unsigned int> deviceGetCount();
 Try<nvmlDevice_t> deviceGetHandleByIndex(unsigned int index);
 Try<unsigned int> deviceGetMinorNumber(nvmlDevice_t handle);