On 5/17/22 14:38, dzej...@gmail.com wrote:
From: Jaroslav Jindrak <dzej...@gmail.com>Prior to the introduction of the prealloc-threads property, the amount of threads used to preallocate memory was derived from the value of smp-cpus passed to qemu, the amount of physical cpus of the host and a hardcoded maximum value. When the prealloc-threads property was introduced, it included a default of 1 in backends/hostmem.c and a default of smp-cpus using the sugar API for the property itself. The latter default is not used when the property is not specified on qemu's command line, so guests that were not adjusted for this change suddenly started to use the default of 1 thread to preallocate memory, which resulted in observable slowdowns in guest boots for guests with large memory (e.g. when using libvirt <8.2.0 or managing guests manually). This commit restores the original behavior for these cases while not impacting guests started with the prealloc-threads property in any way. Fixes: 220c1fd864e9d ("hostmem: introduce "prealloc-threads" property") Signed-off-by: Jaroslav Jindrak <dzej...@gmail.com> --- backends/hostmem.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/backends/hostmem.c b/backends/hostmem.c index a7bae3d713..624bb7ecd3 100644 --- a/backends/hostmem.c +++ b/backends/hostmem.c @@ -274,7 +274,7 @@ static void host_memory_backend_init(Object *obj) backend->merge = machine_mem_merge(machine); backend->dump = machine_dump_guest_core(machine); backend->reserve = true; - backend->prealloc_threads = 1; + backend->prealloc_threads = machine->smp.cpus; }static void host_memory_backend_post_init(Object *obj)
Queued, thanks. Paolo
