Draft svm_allocator for mempool

src/wrap_mempool.cpp

@@ -299,6 +299,60 @@ namespace
   // }}}
 
 
+  // {{{ svm allocator
+
+  // FIXME: Does this need deferred and immediate just like the buffer-level
+  // allocators? (I.e. can I tell whether I am out of memory just from allocations?)
+  class svm_allocator
+  {
+    protected:
+      std::shared_ptr<pyopencl::context> m_context;
+      cl_uint m_alignment;
+      cl_mem_flags m_flags;
+
+    public:
+      svm_allocator(std::shared_ptr<pyopencl::context> const &ctx,
+          cl_uint alignment, cl_mem_flags flags=CL_MEM_READ_WRITE)
+        : m_context(ctx), m_alignment(alignment), m_flags(flags)
+      {
+        if (flags & (CL_MEM_USE_HOST_PTR | CL_MEM_COPY_HOST_PTR))
+          throw pyopencl::error("Allocator", CL_INVALID_VALUE,
+              "cannot specify USE_HOST_PTR or COPY_HOST_PTR flags");
+      }
+
+      svm_allocator(svm_allocator const &src)
+      : m_context(src.m_context), m_alignment(src.m_alignment),
+      m_flags(src.m_flags)
+      { }
+
+      virtual ~svm_allocator()
+      { }
+
+      typedef void *pointer_type;
+      typedef size_t size_type;
+
+      pointer_type allocate(size_type size)
+      {
+        if (size == 0)
+          return nullptr;
+
+        PYOPENCL_PRINT_CALL_TRACE("clSVMalloc");
+        return clSVMAlloc(m_context->data(), m_flags, size, m_alignment);
+      }
+
+      void free(pointer_type p)
+      {
+        clSVMFree(m_context->data(), p);
+      }
+
+      void try_release_blocks()
+      {
+        pyopencl::run_python_gc();
+      }
+  };
+
+  // }}}
+