Re: [libvirt] [PATCH 5/5] rpc: switch virtlockd and virtlogd to use single-threaded dispatch

[Jim Fehlig]

On 03/06/2018 10:58 AM, Daniel P. Berrangé wrote:

Currently both virtlogd and virtlockd use a single worker thread for
dispatching RPC messages. Even this is overkill and their RPC message
handling callbacks all run in short, finite time and so blocking the
main loop is not an issue like you'd see in libvirtd with long running
QEMU commands.

By setting max_workers==0, we can turn off the worker thread and run
these daemons single threaded. This in turn fixes a serious problem in
the virtlockd daemon whereby it looses all fcntl() locks at re-exec due
to multiple threads existing. fcntl() locks only get preserved if the
process is single threaded at time of exec().

Signed-off-by: Daniel P. Berrangé <berra...@redhat.com>
---
  src/locking/lock_daemon.c | 4 ++--
  src/logging/log_daemon.c  | 4 ++--
  2 files changed, 4 insertions(+), 4 deletions(-)

Given the outcome of discussions

Reviewed-by: Jim Fehlig <jfeh...@suse.com>

Regards,
Jim

diff --git a/src/locking/lock_daemon.c b/src/locking/lock_daemon.c
index 79ab90fc91..7afff42246 100644
--- a/src/locking/lock_daemon.c
+++ b/src/locking/lock_daemon.c
@@ -165,7 +165,7 @@ virLockDaemonNew(virLockDaemonConfigPtr config, bool 
privileged)
          goto error;

if (!(srv = virNetServerNew("virtlockd", 1,

-                                1, 1, 0, config->max_clients,
+                                0, 0, 0, config->max_clients,
                                  config->max_clients, -1, 0,
                                  NULL,
                                  virLockDaemonClientNew,
@@ -180,7 +180,7 @@ virLockDaemonNew(virLockDaemonConfigPtr config, bool 
privileged)
      srv = NULL;

if (!(srv = virNetServerNew("admin", 1,

-                                1, 1, 0, config->admin_max_clients,
+                                0, 0, 0, config->admin_max_clients,
                                  config->admin_max_clients, -1, 0,
                                  NULL,
                                  remoteAdmClientNew,
diff --git a/src/logging/log_daemon.c b/src/logging/log_daemon.c
index d54d26ab9d..35d7ebb6d2 100644
--- a/src/logging/log_daemon.c
+++ b/src/logging/log_daemon.c
@@ -154,7 +154,7 @@ virLogDaemonNew(virLogDaemonConfigPtr config, bool 
privileged)
          goto error;

if (!(srv = virNetServerNew("virtlogd", 1,

-                                1, 1, 0, config->max_clients,
+                                0, 0, 0, config->max_clients,
                                  config->max_clients, -1, 0,
                                  NULL,
                                  virLogDaemonClientNew,
@@ -169,7 +169,7 @@ virLogDaemonNew(virLogDaemonConfigPtr config, bool 
privileged)
      srv = NULL;

if (!(srv = virNetServerNew("admin", 1,

-                                1, 1, 0, config->admin_max_clients,
+                                0, 0, 0, config->admin_max_clients,
                                  config->admin_max_clients, -1, 0,
                                  NULL,
                                  remoteAdmClientNew,

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