From: Stefan Hajnoczi <stefanha@redhat.com>
Date: Mon, 27 Jan 2020 19:02:22 +0000
Subject: [PATCH] virtiofsd: add --thread-pool-size=NUM option
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Add an option to control the size of the thread pool.  Requests are now
processed in parallel by default.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
(cherry picked from commit 951b3120dbc971f08681e1d860360e4a1e638902)
---
 tools/virtiofsd/fuse_i.h        | 1 +
 tools/virtiofsd/fuse_lowlevel.c | 7 ++++++-
 tools/virtiofsd/fuse_virtio.c   | 5 +++--
 3 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/tools/virtiofsd/fuse_i.h b/tools/virtiofsd/fuse_i.h
index 1447d86866..4e47e5880d 100644
--- a/tools/virtiofsd/fuse_i.h
+++ b/tools/virtiofsd/fuse_i.h
@@ -72,6 +72,7 @@ struct fuse_session {
     int   vu_listen_fd;
     int   vu_socketfd;
     struct fv_VuDev *virtio_dev;
+    int thread_pool_size;
 };
 
 struct fuse_chan {
diff --git a/tools/virtiofsd/fuse_lowlevel.c b/tools/virtiofsd/fuse_lowlevel.c
index 79a4031266..de2e2e0c65 100644
--- a/tools/virtiofsd/fuse_lowlevel.c
+++ b/tools/virtiofsd/fuse_lowlevel.c
@@ -28,6 +28,7 @@
 #include <sys/file.h>
 #include <unistd.h>
 
+#define THREAD_POOL_SIZE 64
 
 #define OFFSET_MAX 0x7fffffffffffffffLL
 
@@ -2519,6 +2520,7 @@ static const struct fuse_opt fuse_ll_opts[] = {
     LL_OPTION("allow_root", deny_others, 1),
     LL_OPTION("--socket-path=%s", vu_socket_path, 0),
     LL_OPTION("--fd=%d", vu_listen_fd, 0),
+    LL_OPTION("--thread-pool-size=%d", thread_pool_size, 0),
     FUSE_OPT_END
 };
 
@@ -2537,7 +2539,9 @@ void fuse_lowlevel_help(void)
     printf(
         "    -o allow_root              allow access by root\n"
         "    --socket-path=PATH         path for the vhost-user socket\n"
-        "    --fd=FDNUM                 fd number of vhost-user socket\n");
+        "    --fd=FDNUM                 fd number of vhost-user socket\n"
+        "    --thread-pool-size=NUM     thread pool size limit (default %d)\n",
+        THREAD_POOL_SIZE);
 }
 
 void fuse_session_destroy(struct fuse_session *se)
@@ -2591,6 +2595,7 @@ struct fuse_session *fuse_session_new(struct fuse_args *args,
     }
     se->fd = -1;
     se->vu_listen_fd = -1;
+    se->thread_pool_size = THREAD_POOL_SIZE;
     se->conn.max_write = UINT_MAX;
     se->conn.max_readahead = UINT_MAX;
 
diff --git a/tools/virtiofsd/fuse_virtio.c b/tools/virtiofsd/fuse_virtio.c
index 0dcf2ef57a..9f6582343c 100644
--- a/tools/virtiofsd/fuse_virtio.c
+++ b/tools/virtiofsd/fuse_virtio.c
@@ -572,10 +572,11 @@ static void *fv_queue_thread(void *opaque)
     struct fv_QueueInfo *qi = opaque;
     struct VuDev *dev = &qi->virtio_dev->dev;
     struct VuVirtq *q = vu_get_queue(dev, qi->qidx);
+    struct fuse_session *se = qi->virtio_dev->se;
     GThreadPool *pool;
 
-    pool = g_thread_pool_new(fv_queue_worker, qi, 1 /* TODO max_threads */,
-                             TRUE, NULL);
+    pool = g_thread_pool_new(fv_queue_worker, qi, se->thread_pool_size, TRUE,
+                             NULL);
     if (!pool) {
         fuse_log(FUSE_LOG_ERR, "%s: g_thread_pool_new failed\n", __func__);
         return NULL;