From 47c578945cb8a112d3b5599514f0d5a52993a2ba Mon Sep 17 00:00:00 2001
From: Kenny Levinsen <kl@kl.wtf>
Date: Thu, 20 Jun 2024 01:56:09 +0200
Subject: [PATCH] render/vulkan: Recycle memory maps for stage spans

Remapping buffers on every use causes a lot of unwanted pagefaults.
Reuse the mapping to significantly speed up the memcpy.
---
 include/render/vulkan.h  |  1 +
 render/vulkan/renderer.c |  4 ++++
 render/vulkan/texture.c  | 21 +++++++++------------
 3 files changed, 14 insertions(+), 12 deletions(-)

diff --git a/include/render/vulkan.h b/include/render/vulkan.h
index 6d3da153..5b74b613 100644
--- a/include/render/vulkan.h
+++ b/include/render/vulkan.h
@@ -483,6 +483,7 @@ struct wlr_vk_shared_buffer {
 	VkBuffer buffer;
 	VkDeviceMemory memory;
 	VkDeviceSize buf_size;
+	void *cpu_mapping;
 	struct wl_array allocs; // struct wlr_vk_allocation
 };
 
diff --git a/render/vulkan/renderer.c b/render/vulkan/renderer.c
index b0203490..3aa66e5c 100644
--- a/render/vulkan/renderer.c
+++ b/render/vulkan/renderer.c
@@ -187,6 +187,10 @@ static void shared_buffer_destroy(struct wlr_vk_renderer *r,
 	if (buffer->memory) {
 		vkFreeMemory(r->dev->dev, buffer->memory, NULL);
 	}
+	if (buffer->cpu_mapping) {
+		vkUnmapMemory(r->dev->dev, buffer->memory);
+		buffer->cpu_mapping = NULL;
+	}
 
 	wl_list_remove(&buffer->link);
 	free(buffer);
diff --git a/render/vulkan/texture.c b/render/vulkan/texture.c
index 0e7a572b..086f59f8 100644
--- a/render/vulkan/texture.c
+++ b/render/vulkan/texture.c
@@ -80,19 +80,19 @@ static bool write_pixels(struct wlr_vk_texture *texture,
 		return false;
 	}
 
-	void *vmap;
-	res = vkMapMemory(dev, span.buffer->memory, span.alloc.start,
-		bsize, 0, &vmap);
-	if (res != VK_SUCCESS) {
-		wlr_vk_error("vkMapMemory", res);
-		free(copies);
-		return false;
+	if (!span.buffer->cpu_mapping) {
+		res = vkMapMemory(dev, span.buffer->memory, 0, VK_WHOLE_SIZE, 0, &span.buffer->cpu_mapping);
+		if (res != VK_SUCCESS) {
+			wlr_vk_error("vkMapMemory", res);
+			free(copies);
+			return false;
+		}
 	}
-	char *map = (char *)vmap;
+	char *map = (char*)span.buffer->cpu_mapping + span.alloc.start;
 
 	// upload data
 
-	uint32_t buf_off = span.alloc.start + (map - (char *)vmap);
+	uint32_t buf_off = span.alloc.start;
 	for (int i = 0; i < rects_len; i++) {
 		pixman_box32_t rect = rects[i];
 		uint32_t width = rect.x2 - rect.x1;
@@ -137,9 +137,6 @@ static bool write_pixels(struct wlr_vk_texture *texture,
 		buf_off += height * packed_stride;
 	}
 
-	assert((uint32_t)(map - (char *)vmap) == bsize);
-	vkUnmapMemory(dev, span.buffer->memory);
-
 	// record staging cb
 	// will be executed before next frame
 	VkCommandBuffer cb = vulkan_record_stage_cb(renderer);