Re: [libvirt] [PATCH v2 09/10] admin: Introduce virAdmServerSetThreadPoolParameters

Since threadpool increments the current number of threads according to current load, i.e. how many jobs are waiting in the queue. The count however, is constrained by max and min limits of workers. The logic of this new API works like this: 1) setting the minimum a) When the limit is increased, depending on the current number of threads, new threads are possibly spawned if the current number of threads is less than the new minimum limit b) Decreasing the minimum limit has no possible effect on the current number of threads 2) setting the maximum a) Icreasing the maximum limit has no immediate effect on the current number of threads, it only allows the threadpool to spawn more threads when new jobs, that would otherwise end up queued, arrive. b) Decreasing the maximum limit may affect the current number of threads, if the current number of threads is less than the new maximum limit. Since there may be some ongoing time-consuming jobs that would effectively block this API from killing any threads. Therefore, this API is asynchronous with best-effort execution, i.e. the necessary number of workers will be terminated once they finish their previous job, unless other workers had already terminated, decreasing the limit to the requested value. 3) setting priority workers - both increase and decrease in count of these workers have an immediate impact on the current number of workers, new ones will be spawned or some of them get terminated respectively. --- daemon/admin.c | 43 +++++++++++++++++++++++ daemon/admin_server.c | 43 +++++++++++++++++++++++ daemon/admin_server.h | 5 +++ include/libvirt/libvirt-admin.h | 5 +++ src/admin/admin_protocol.x | 13 ++++++- src/admin/admin_remote.c | 34 ++++++++++++++++++ src/admin_protocol-structs | 9 +++++ src/libvirt-admin.c | 37 ++++++++++++++++++++ src/libvirt_admin_private.syms | 1 + src/libvirt_admin_public.syms | 1 + src/libvirt_private.syms | 1 + src/rpc/virnetserver.c | 15 ++++++++ src/util/virthreadpool.c | 77 +++++++++++++++++++++++++++++++++++++++-- src/util/virthreadpool.h | 5 +++ 14 files changed, 285 insertions(+), 4 deletions(-)

diff --git a/src/libvirt-admin.c b/src/libvirt-admin.c index c528f79..9b31ad2 100644 --- a/src/libvirt-admin.c +++ b/src/libvirt-admin.c @@ -720,3 +720,40 @@ virAdmServerGetThreadPoolParameters(virAdmServerPtr srv, virDispatchError(NULL); return -1; } + +/** + * virAdmServerSetThreadPoolParameters: + * @srv: a valid server object reference + * @params: pointer to threadpool parameter objects + * @nparams: number of parameters in @params + * @flags: bitwise-OR of extra flags virAdmServerSetThreadPoolParametersFlags + * + * Change server threadpool parameters according to @params. Note that some + * tunables are read-only, thus any attempt to set them will result in a + * failure. + * + * Returns 0 on success, -1 in case of an error. + */ +int +virAdmServerSetThreadPoolParameters(virAdmServerPtr srv, + virTypedParameterPtr params, + int nparams, + unsigned int flags) +{ + VIR_DEBUG("srv=%p, params=%p, nparams=%x, flags=%x", + srv, params, nparams, flags); + + virResetLastError(); + + virCheckAdmServerReturn(srv, NULL);

+ virCheckNonNullArgGoto(params, error); + + if (remoteAdminServerSetThreadPoolParameters(srv, params, + nparams, flags) < 0) + goto error; + + return 0; + error: + virDispatchError(NULL); + return -1; +}