bring back sysfs based VRAM information for AMD (#12871)

* build: optimize dockerfile context for iterating

This moves the copy of the source into the layer AFTER
doing software installs so we don't have to go through
the RPM install for cuda, etc. every time you touch a
source file.

* amd: implement linux sysfs based VRAM lookup

This adds a C++ implementation of sysfs DRM VRAM discovery
for more accurate free VRAM data on linux for AMD GPUs.

ml/backend/ggml/ggml/src/ggml-cuda/ggml-cuda.cu

@@ -3513,7 +3513,7 @@ static void ggml_backend_cuda_device_get_memory(ggml_backend_dev_t dev, size_t *
     if (ggml_hip_mgmt_init() == 0) {
         int status = ggml_hip_get_device_memory(ctx->pci_bus_id.c_str(), free, total);
         if (status == 0) {
-            GGML_LOG_DEBUG("%s device %s utilizing ADLX memory reporting free: %zu total: %zu\n", __func__, ctx->pci_bus_id.c_str(), *free, *total);
+            GGML_LOG_DEBUG("%s device %s utilizing AMD specific memory reporting free: %zu total: %zu\n", __func__, ctx->pci_bus_id.c_str(), *free, *total);
             ggml_hip_mgmt_release();
             return;
         }

ml/backend/ggml/ggml/src/ggml-vulkan/ggml-vulkan.cpp

@@ -13212,7 +13212,7 @@ void ggml_backend_vk_get_device_memory(ggml_backend_vk_device_context *ctx, size
             if (ggml_hip_mgmt_init() == 0) {
                 int status = ggml_hip_get_device_memory(ctx->pci_id != "" ? ctx->pci_id.c_str() : ctx->uuid.c_str(), free, total);
                 if (status == 0) {
-                    GGML_LOG_DEBUG("%s device %s utilizing ADLX memory reporting free: %zu total: %zu\n", __func__, ctx->pci_id != "" ? ctx->pci_id.c_str() : ctx->uuid.c_str(), *free, *total);
+                    GGML_LOG_DEBUG("%s device %s utilizing AMD specific memory reporting free: %zu total: %zu\n", __func__, ctx->pci_id != "" ? ctx->pci_id.c_str() : ctx->uuid.c_str(), *free, *total);
                     ggml_hip_mgmt_release();
                     return;
                 }

ml/backend/ggml/ggml/src/mem_hip.cpp

@@ -1,4 +1,5 @@
 #include "ggml.h"
+#include "ggml-impl.h"
 
 #ifdef _WIN32
 // AMD Device Library eXtra (ADLX)
@@ -16,7 +17,6 @@
 // Unused function parameters are commented out to avoid unnecessary type
 // definitions.
 
-#include "ggml-impl.h"
 #include <filesystem>
 #include <mutex>
 
@@ -436,15 +436,92 @@ int ggml_hip_get_device_memory(const char *id, size_t *free, size_t *total) {
 
 #else // #ifdef _WIN32
 
+#include <fstream>
+#include <iostream>
+#include <sstream>
+#include <string>
+#include <vector>
+#include <filesystem>
+
+#include <sys/stat.h>
+#include <dirent.h>
+#include <unistd.h>
+#include <glob.h>
+namespace fs = std::filesystem;
+
 extern "C" {
 
-// TODO Linux implementation of accurate VRAM reporting
 int ggml_hip_mgmt_init() {
-    return -1;
+    return 0;
 }
 void ggml_hip_mgmt_release() {}
 int ggml_hip_get_device_memory(const char *id, size_t *free, size_t *total) {
-    return -1;
+    GGML_LOG_INFO("%s searching for device %s\n", __func__, id);
+    const std::string drmDeviceGlob = "/sys/class/drm/card*/device/uevent";
+    const std::string drmTotalMemoryFile = "mem_info_vram_total";
+    const std::string drmUsedMemoryFile = "mem_info_vram_used";
+    const std::string drmUeventPCISlotLabel = "PCI_SLOT_NAME=";
+
+    glob_t glob_result;
+    glob(drmDeviceGlob.c_str(), GLOB_NOSORT, NULL, &glob_result);
+
+    for (size_t i = 0; i < glob_result.gl_pathc; ++i) {
+        const char* device_file = glob_result.gl_pathv[i];
+        std::ifstream file(device_file);
+        if (!file.is_open()) {
+            std::cerr << "Failed to open sysfs node" << std::endl;
+            globfree(&glob_result);
+            return 1;
+        }
+
+        std::string line;
+        while (std::getline(file, line)) {
+            // Check for PCI_SLOT_NAME label
+            if (line.find(drmUeventPCISlotLabel) == 0) {
+                std::istringstream iss(line.substr(drmUeventPCISlotLabel.size()));
+                std::string pciSlot;
+                iss >> pciSlot;
+                if (pciSlot == std::string(id)) {
+                    std::string dir = fs::path(device_file).parent_path().string();
+
+                    std::string totalFile = dir + "/" + drmTotalMemoryFile;
+                    std::ifstream totalFileStream(totalFile.c_str());
+                    if (!totalFileStream.is_open()) {
+                        GGML_LOG_DEBUG("%s Failed to read sysfs node %s\n", __func__, totalFile.c_str());
+                        file.close();
+                        globfree(&glob_result);
+                        return 1;
+                    }
+
+                    uint64_t memory;
+                    totalFileStream >> memory;
+                    *total = memory;
+
+                    std::string usedFile = dir + "/" + drmUsedMemoryFile;
+                    std::ifstream usedFileStream(usedFile.c_str());
+                    if (!usedFileStream.is_open()) {
+                        GGML_LOG_DEBUG("%s Failed to read sysfs node %s\n", __func__, usedFile.c_str());
+                        file.close();
+                        globfree(&glob_result);
+                        return 1;
+                    }
+
+                    uint64_t memoryUsed;
+                    usedFileStream >> memoryUsed;
+                    *free = memory - memoryUsed;
+
+                    file.close();
+                    globfree(&glob_result);
+                    return 0;
+                }
+            }
+        }
+
+        file.close();
+    }
+    GGML_LOG_DEBUG("%s unable to find matching device\n", __func__);
+    globfree(&glob_result);
+    return 1;
 }
 
 } // extern "C"