llama : disable Direct IO by default (#19109)

* llama : disable Direct IO by default

* cont : override mmap if supported

src/llama-model-loader.cpp

@@ -541,15 +541,15 @@ llama_model_loader::llama_model_loader(
 
     if (use_mmap && use_direct_io) {
         if (files.back()->has_direct_io()) {
-            // Disable mmap, as DirectIO is available
-            use_mmap = false;
             LLAMA_LOG_WARN("%s: direct I/O is enabled, disabling mmap\n", __func__);
+            use_mmap = false;
         } else {
-            // Disable DirectIO and reopen file using std::fopen for mmap
+            LLAMA_LOG_WARN("%s: direct I/O is not available, using mmap\n", __func__);
             use_direct_io = false;
+
+            // reopen file using std::fopen for mmap
             files.pop_back();
             files.emplace_back(new llama_file(fname.c_str(), "rb", false));
-            LLAMA_LOG_WARN("%s: direct I/O is not available, using mmap\n", __func__);
         }
     }
 

src/llama-model.cpp

@@ -8125,7 +8125,7 @@ llama_model_params llama_model_default_params() {
         /*.kv_overrides                =*/ nullptr,
         /*.vocab_only                  =*/ false,
         /*.use_mmap                    =*/ true,
-        /*.use_direct_io               =*/ true,
+        /*.use_direct_io               =*/ false,
         /*.use_mlock                   =*/ false,
         /*.check_tensors               =*/ false,
         /*.use_extra_bufts             =*/ true,

src/llama-quant.cpp

@@ -545,7 +545,7 @@ static void llama_model_quantize_impl(const std::string & fname_inp, const std::
     }
 
     std::vector<std::string> splits = {};
-    llama_model_loader ml(fname_inp, splits, use_mmap, /*use_direct_io*/ true, /*check_tensors*/ true, /*no_alloc*/ false, kv_overrides, nullptr);
+    llama_model_loader ml(fname_inp, splits, use_mmap, /*use_direct_io*/ false, /*check_tensors*/ true, /*no_alloc*/ false, kv_overrides, nullptr);
     ml.init_mappings(false); // no prefetching
 
     llama_model model(llama_model_default_params());