[libvirt] [PATCH 0/9] Resolve libvirtd hang on termination with connected long running client

[Nikolay Shirokovskiy]

Hi, John.

Thank you for driving this issue! Unfortunately I have little time now
to take participation in reviweing etc.

Nikolay

On 19.01.2018 20:23, John Ferlan wrote:
> RFC:
> https://www.redhat.com/archives/libvir-list/2018-January/msg00318.html
> 
> Adjustments since RFC...
> 
> Patches 1&2: No change, were already R-B'd
> Patch 3: Removed code as noted in code review, update commit message
> Patch 4: From old series removed, see below for more details
> Patch 9: no change
> NB: Patches 5-8 and 10 from Nikolay Shirokovskiy <nshirokovskiy at virtuozzo.com>
>     are removed as they seemed to not be necessary
> 
> Replaced the former patch 4 with series of patches to (slowly) provide
> support to disable new connections, handle removing waiting jobs, causing
> the waiting workers to quit, and allow any running jobs to complete.
> 
> As it turns out, waiting for running jobs to complete cannot be done
> from the virNetServerClose callbacks because that means the event loop
> processing done during virNetServerRun will not allow any currently
> long running worker job thread a means to complete.
> 
> So when virNetDaemonQuit is called as a result of the libvirtd signal
> handlers for SIG{QUIT|INT|TERM}, instead of just causing virNetServerRun
> to quit immediately, alter to using a quitRequested flag and then use
> that quitRequested flag to check for long running worker threads before
> causing the event loop to quit resulting in libvirtd being able to run
> through the virNetDaemonClose processing.
> 
> John Ferlan (9):
>   libvirtd: Alter refcnt processing for domain server objects
>   libvirtd: Alter refcnt processing for server program objects
>   netserver: Remove ServiceToggle during ServerDispose
>   util: Introduce virThreadPoolDrain
>   rpc: Introduce virNetServerQuitRequested
>   rpc: Introduce virNetServerWorkerCount
>   rpc: Alter virNetDaemonQuit processing
>   docs: Add news article for libvirtd issue
>   APPLY ONLY FOR TESTING PURPOSES
> 
>  daemon/libvirtd.c        | 43 +++++++++++++++++++++++---------
>  docs/news.xml            | 12 +++++++++
>  src/libvirt_private.syms |  1 +
>  src/libvirt_remote.syms  |  2 ++
>  src/qemu/qemu_driver.c   |  5 ++++
>  src/rpc/virnetdaemon.c   | 45 +++++++++++++++++++++++++++++++++-
>  src/rpc/virnetserver.c   | 52 ++++++++++++++++++++++++++++++++++++---
>  src/rpc/virnetserver.h   |  4 +++
>  src/util/virthreadpool.c | 64 ++++++++++++++++++++++++++++++++++++++++--------
>  src/util/virthreadpool.h |  2 ++
>  10 files changed, 204 insertions(+), 26 deletions(-)
>