[PULL 25/26] virtiofsd: Used glib "shared" thread pool

[Dr. David Alan Gilbert (git)]

From: Vivek Goyal <vgoyal@redhat.com>

glib offers thread pools and it seems to support "exclusive" and "shared"
thread pools.

https://developer.gnome.org/glib/stable/glib-Thread-Pools.html#g-thread-pool-new

Currently we use "exlusive" thread pools but its performance seems to be
poor. I tried using "shared" thread pools and performance seems much
better. I posted performance results here.

https://www.redhat.com/archives/virtio-fs/2020-September/msg00080.html

So lets switch to shared thread pools. We can think of making it optional
once somebody can show in what cases exclusive thread pools offer better
results. For now, my simple performance tests across the board see
better results with shared thread pools.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Message-Id: <20200921213216.GE13362@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
  With seccomp fix from Miklos
---
 tools/virtiofsd/fuse_virtio.c         | 2 +-
 tools/virtiofsd/passthrough_seccomp.c | 2 ++
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/tools/virtiofsd/fuse_virtio.c b/tools/virtiofsd/fuse_virtio.c
index 9e5537506c..d5c8e98253 100644
--- a/tools/virtiofsd/fuse_virtio.c
+++ b/tools/virtiofsd/fuse_virtio.c
@@ -588,7 +588,7 @@ static void *fv_queue_thread(void *opaque)
     struct fuse_session *se = qi->virtio_dev->se;
     GThreadPool *pool;
 
-    pool = g_thread_pool_new(fv_queue_worker, qi, se->thread_pool_size, TRUE,
+    pool = g_thread_pool_new(fv_queue_worker, qi, se->thread_pool_size, FALSE,
                              NULL);
     if (!pool) {
         fuse_log(FUSE_LOG_ERR, "%s: g_thread_pool_new failed\n", __func__);
diff --git a/tools/virtiofsd/passthrough_seccomp.c 
b/tools/virtiofsd/passthrough_seccomp.c
index 19fee60011..eb9af8265f 100644
--- a/tools/virtiofsd/passthrough_seccomp.c
+++ b/tools/virtiofsd/passthrough_seccomp.c
@@ -93,6 +93,8 @@ static const int syscall_whitelist[] = {
     SCMP_SYS(rt_sigaction),
     SCMP_SYS(rt_sigprocmask),
     SCMP_SYS(rt_sigreturn),
+    SCMP_SYS(sched_getattr),
+    SCMP_SYS(sched_setattr),
     SCMP_SYS(sendmsg),
     SCMP_SYS(setresgid),
     SCMP_SYS(setresuid),
-- 
2.26.2