ggml-cuda: flush legacy pool on OOM and retry (#22155)

* ggml-cuda: flush legacy pool on OOM and retry

Signed-off-by: 梁厚宏 <2695316095@qq.com>

* Address review comments: add explicit sync, update destructor, clean up MUSA macros

Signed-off-by: 梁厚宏 <2695316095@qq.com>

---------

Signed-off-by: 梁厚宏 <2695316095@qq.com>

ggml/src/ggml-cuda/ggml-cuda.cu

@@ -368,15 +368,21 @@ struct ggml_cuda_pool_leg : public ggml_cuda_pool {
     }
 
     ~ggml_cuda_pool_leg() {
+        clear_pool();
+        GGML_ASSERT(pool_size == 0);
+    }
+
+    void clear_pool() {
         ggml_cuda_set_device(device);
         for (int i = 0; i < MAX_BUFFERS; ++i) {
             ggml_cuda_buffer & b = buffer_pool[i];
             if (b.ptr != nullptr) {
                 CUDA_CHECK(cudaFree(b.ptr));
                 pool_size -= b.size;
+                b.ptr  = nullptr;
+                b.size = 0;
             }
         }
-        GGML_ASSERT(pool_size == 0);
     }
 
     void * alloc(size_t size, size_t * actual_size) override {
@@ -421,7 +427,20 @@ struct ggml_cuda_pool_leg : public ggml_cuda_pool {
         size_t look_ahead_size = (size_t) (1.05 * size);
         look_ahead_size = 256 * ((look_ahead_size + 255)/256);
         ggml_cuda_set_device(device);
-        CUDA_CHECK(ggml_cuda_device_malloc(&ptr, look_ahead_size, device));
+        cudaError_t err = ggml_cuda_device_malloc(&ptr, look_ahead_size, device);
+        if (err == cudaErrorMemoryAllocation) {
+            (void)cudaGetLastError();
+            const size_t cached_bytes = pool_size;
+            GGML_LOG_DEBUG(GGML_CUDA_NAME " pool[%d]: alloc of %.2f MiB failed, flushing %.2f MiB of cached buffers and retrying\n",
+                           device, look_ahead_size/1024.0/1024.0, cached_bytes/1024.0/1024.0);
+            CUDA_CHECK(cudaDeviceSynchronize());
+            clear_pool();
+            err = ggml_cuda_device_malloc(&ptr, look_ahead_size, device);
+            if (err == cudaSuccess) {
+                GGML_LOG_DEBUG(GGML_CUDA_NAME " pool[%d]: retry succeeded\n", device);
+            }
+        }
+        CUDA_CHECK(err);
         *actual_size = look_ahead_size;
         pool_size += look_ahead_size;
 #ifdef DEBUG_CUDA_MALLOC

ggml/src/ggml-cuda/vendors/hip.h

@@ -58,6 +58,7 @@
 #define cudaDeviceProp hipDeviceProp_t
 #define cudaDeviceSynchronize hipDeviceSynchronize
 #define cudaError_t hipError_t
+#define cudaErrorMemoryAllocation hipErrorOutOfMemory
 #define cudaErrorPeerAccessAlreadyEnabled hipErrorPeerAccessAlreadyEnabled
 #define cudaErrorPeerAccessNotEnabled hipErrorPeerAccessNotEnabled
 #define cudaEventCreateWithFlags hipEventCreateWithFlags

ggml/src/ggml-cuda/vendors/musa.h

@@ -42,6 +42,7 @@
 #define cudaDeviceProp musaDeviceProp
 #define cudaDeviceSynchronize musaDeviceSynchronize
 #define cudaError_t musaError_t
+#define cudaErrorMemoryAllocation musaErrorMemoryAllocation
 #define cudaErrorPeerAccessAlreadyEnabled musaErrorPeerAccessAlreadyEnabled
 #define cudaErrorPeerAccessNotEnabled musaErrorPeerAccessNotEnabled
 #define cudaEventCreateWithFlags musaEventCreateWithFlags