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| author | Dmitrii Gavrilov <ds-gavr@yandex-team.ru> | 2023-11-03 13:56:02 +0300 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2024-03-08 15:51:21 +0100 |
| commit | 012b170173bcaa14b9bc26209e0813311ac78489 (patch) | |
| tree | 5254158ec2b6b342d6ed72b1f8ae44ac2cf26e94 /system | |
| parent | 9876359990dd4c8a48de65cf5e1c3d13e96a7f4e (diff) | |
| download | qemu-012b170173bcaa14b9bc26209e0813311ac78489.zip qemu-012b170173bcaa14b9bc26209e0813311ac78489.tar.gz qemu-012b170173bcaa14b9bc26209e0813311ac78489.tar.bz2 | |
system/qdev-monitor: move drain_call_rcu call under if (!dev) in qmp_device_add()
Original goal of addition of drain_call_rcu to qmp_device_add was to cover
the failure case of qdev_device_add. It seems call of drain_call_rcu was
misplaced in 7bed89958bfbf40df what led to waiting for pending RCU callbacks
under happy path too. What led to overall performance degradation of
qmp_device_add.
In this patch call of drain_call_rcu moved under handling of failure of
qdev_device_add.
Signed-off-by: Dmitrii Gavrilov <ds-gavr@yandex-team.ru>
Message-ID: <20231103105602.90475-1-ds-gavr@yandex-team.ru>
Fixes: 7bed89958bf ("device_core: use drain_call_rcu in in qmp_device_add", 2020-10-12)
Cc: qemu-stable@nongnu.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'system')
| -rw-r--r-- | system/qdev-monitor.c | 23 |
1 files changed, 11 insertions, 12 deletions
diff --git a/system/qdev-monitor.c b/system/qdev-monitor.c index a13db76..874d651 100644 --- a/system/qdev-monitor.c +++ b/system/qdev-monitor.c @@ -858,19 +858,18 @@ void qmp_device_add(QDict *qdict, QObject **ret_data, Error **errp) return; } dev = qdev_device_add(opts, errp); - - /* - * Drain all pending RCU callbacks. This is done because - * some bus related operations can delay a device removal - * (in this case this can happen if device is added and then - * removed due to a configuration error) - * to a RCU callback, but user might expect that this interface - * will finish its job completely once qmp command returns result - * to the user - */ - drain_call_rcu(); - if (!dev) { + /* + * Drain all pending RCU callbacks. This is done because + * some bus related operations can delay a device removal + * (in this case this can happen if device is added and then + * removed due to a configuration error) + * to a RCU callback, but user might expect that this interface + * will finish its job completely once qmp command returns result + * to the user + */ + drain_call_rcu(); + qemu_opts_del(opts); return; } |