Merge branch 'async-master' into 'master'

Draft: render,types/wlr_shm: Offload slow cleanup ops

See merge request wlroots/wlroots!4755

include/util/cleanup.h

@@ -0,0 +1,10 @@
+typedef void (*wlr_task_cb)(void *data);
+
+struct wlr_task {
+	wlr_task_cb task;
+	void *data;
+};
+
+void wlr_cleanup_queue_init(void);
+void wlr_cleanup_queue_finish(void);
+void wlr_cleanup_defer(struct wlr_task t);

meson.build

@@ -122,6 +122,7 @@ pixman = dependency('pixman-1',
 )
 math = cc.find_library('m')
 rt = cc.find_library('rt')
+threads = dependency('threads')
 
 wlr_files = []
 wlr_deps = [
@@ -131,6 +132,7 @@ wlr_deps = [
 	pixman,
 	math,
 	rt,
+	threads,
 ]
 
 subdir('protocol')

render/dmabuf.c

@@ -1,15 +1,31 @@
 #include <fcntl.h>
+#include <stdlib.h>
 #include <unistd.h>
 #include <wlr/render/dmabuf.h>
 #include <wlr/util/log.h>
 #include "render/dmabuf.h"
+#include "util/cleanup.h"
+
+static void defer_close_dmabuf(void *data) {
+	struct wlr_dmabuf_attributes *attribs = data;
 
-void wlr_dmabuf_attributes_finish(struct wlr_dmabuf_attributes *attribs) {
 	for (int i = 0; i < attribs->n_planes; ++i) {
 		close(attribs->fd[i]);
+	}
+	free(attribs);
+}
+
+void wlr_dmabuf_attributes_finish(struct wlr_dmabuf_attributes *attribs) {
+	struct wlr_dmabuf_attributes *attribs_defer = calloc(1, sizeof(struct wlr_dmabuf_attributes));
+
+	attribs_defer->n_planes = attribs->n_planes;
+	for (int i = 0; i < attribs->n_planes; ++i) {
+		attribs_defer->fd[i] = attribs->fd[i];
 		attribs->fd[i] = -1;
 	}
 	attribs->n_planes = 0;
+
+	wlr_cleanup_defer((struct wlr_task){&defer_close_dmabuf, attribs_defer});
 }
 
 bool wlr_dmabuf_attributes_copy(struct wlr_dmabuf_attributes *dst,

types/wlr_shm.c

@@ -14,6 +14,7 @@
 #include <wlr/types/wlr_shm.h>
 #include <wlr/util/log.h>
 #include "render/pixel_format.h"
+#include "util/cleanup.h"
 
 #ifdef __STDC_NO_ATOMICS__
 #error "C11 atomics are required"
@@ -116,6 +117,12 @@ static struct wlr_shm_mapping *mapping_create(int fd, size_t size) {
 	return mapping;
 }
 
+static void defer_munmap(void *data) {
+	struct wlr_shm_mapping *mapping = data;
+	munmap(mapping->data, mapping->size);
+	free(mapping);
+}
+
 static void mapping_consider_destroy(struct wlr_shm_mapping *mapping) {
 	if (!mapping->dropped) {
 		return;
@@ -127,8 +134,7 @@ static void mapping_consider_destroy(struct wlr_shm_mapping *mapping) {
 		}
 	}
 
-	munmap(mapping->data, mapping->size);
-	free(mapping);
+	wlr_cleanup_defer((struct wlr_task){&defer_munmap, mapping});
 }
 
 /**
@@ -400,13 +406,18 @@ static const struct wl_shm_pool_interface pool_impl = {
 	.resize = pool_handle_resize,
 };
 
+static void defer_close_fd(void *data) {
+	int fd = (int)(uintptr_t)data;
+	close(fd);
+}
+
 static void pool_consider_destroy(struct wlr_shm_pool *pool) {
 	if (pool->resource != NULL || !wl_list_empty(&pool->buffers)) {
 		return;
 	}
 
 	mapping_drop(pool->mapping);
-	close(pool->fd);
+	wlr_cleanup_defer((struct wlr_task){&defer_close_fd, (void *)(uintptr_t)pool->fd});
 	free(pool);
 }
 

util/cleanup.c

@@ -0,0 +1,86 @@
+#include "util/cleanup.h"
+
+#include <pthread.h>
+#include <stdbool.h>
+#include <string.h>
+#include <sys/eventfd.h>
+#include <unistd.h>
+
+#define MAX_TASKS 16
+struct work_queue {
+	struct wlr_task list[MAX_TASKS];
+	int size;
+	bool running;
+
+	pthread_mutex_t lock;
+	pthread_t thread;
+	int efd;
+};
+
+static struct work_queue queue;
+
+static void *cleanup_thread(void *unused)
+{
+	struct wlr_task work[MAX_TASKS];
+	eventfd_t v;
+	do {
+		eventfd_read(queue.efd, &v);
+
+		pthread_mutex_lock(&queue.lock);
+		for (int i = 0; i < (int)v; i++) {
+			work[i] = queue.list[i];
+		}
+		for (int i = (int)v; i < queue.size; i++) {
+			queue.list[i - v] = queue.list[i];
+		}
+		queue.size -= (int)v;
+		pthread_mutex_unlock(&queue.lock);
+
+		for (int i = 0; i < (int)v; i++) {
+			work[i].task(work[i].data);
+		}
+	} while (queue.running);
+
+	return NULL;
+}
+
+extern void wlr_cleanup_defer(struct wlr_task t)
+{
+	wlr_cleanup_queue_init();
+
+	pthread_mutex_lock(&queue.lock);
+	if (queue.size < MAX_TASKS) {
+		queue.list[queue.size] = t;
+		queue.size++;
+	} else {
+		// In case too much work is queue, apply backpressure.
+		pthread_mutex_unlock(&queue.lock);
+		return t.task(t.data);
+	}
+	pthread_mutex_unlock(&queue.lock);
+	eventfd_write(queue.efd, 1);
+}
+
+extern void wlr_cleanup_queue_init(void)
+{
+	if (!queue.running) {
+		queue = (struct work_queue){0};
+		queue.running = true;
+		queue.efd = eventfd(0, 0);
+		pthread_mutex_init(&queue.lock, NULL);
+		pthread_create(&queue.thread, NULL, cleanup_thread, NULL);
+	}
+}
+
+static void done(void *unused) { queue.running = false; }
+
+extern void wlr_cleanup_queue_finish(void)
+{
+	if (queue.running) {
+		// Notify the cleanup thread that it's done.
+		wlr_cleanup_defer((struct wlr_task){&done, NULL});
+		pthread_join(queue.thread, NULL);
+		close(queue.efd);
+		queue = (struct work_queue){0};
+	}
+}

util/meson.build

@@ -15,4 +15,5 @@ wlr_files += files(
 	'token.c',
 	'transform.c',
 	'utf8.c',
+	'cleanup.c',
 )