heap: try VMH when system heap is exhausted

This is a temporary measure before removing VMH and increasing the
system heap for Linux configurations. Currently the system heap
allocations can fail in cases when multiple (tyipcally more than 5)
streams are started. These are rather extreme testing scenarios,
unlikely to occur in real use-cases, but to give them a chance to
succeed try to fall back to VMH in such cases.

Signed-off-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
(cherry picked from commit 9eeae8c)

Author: lyakh

zephyr/lib/alloc.c

@@ -625,6 +625,13 @@ void *rmalloc_align(uint32_t flags, size_t bytes, uint32_t alignment)
 		ptr = heap_alloc_aligned(heap, alignment, bytes);
 	}
 
+#if CONFIG_VIRTUAL_HEAP
+	if (!ptr && heap == &sof_heap && virtual_buffers_heap) {
+		tr_warn(&zephyr_tr, "system heap allocation of %zu failed, trying VMH", bytes);
+		ptr = virtual_heap_alloc(virtual_buffers_heap, flags, bytes, alignment);
+	}
+#endif
+
 	return ptr;
 }
 EXPORT_SYMBOL(rmalloc_align);
@@ -781,10 +788,21 @@ void *z_impl_sof_heap_alloc(struct k_heap *heap, uint32_t flags, size_t bytes,
 		heap = &sof_heap;
 	}
 
+	void *ptr;
+
 	if (flags & SOF_MEM_FLAG_COHERENT)
-		return heap_alloc_aligned(heap, alignment, bytes);
+		ptr = heap_alloc_aligned(heap, alignment, bytes);
+	else
+		ptr = (__sparse_force void *)heap_alloc_aligned_cached(heap, alignment, bytes);
 
-	return (__sparse_force void *)heap_alloc_aligned_cached(heap, alignment, bytes);
+#if CONFIG_VIRTUAL_HEAP
+	if (!ptr && heap == &sof_heap && virtual_buffers_heap) {
+		tr_warn(&zephyr_tr, "system heap allocation of %zu failed, trying VMH", bytes);
+		ptr = virtual_heap_alloc(virtual_buffers_heap, flags, bytes, alignment);
+	}
+#endif
+
+	return ptr;
 }
 
 void z_impl_sof_heap_free(struct k_heap *heap, void *addr)