On Wed, 2022-07-13 at 17:25 +0100, Daniel P. Berrangé wrote: > It would need to use SCOPE_THREAD_GROUP, except even that is not > sufficient > as the helper may have fork+exec'd another helper by this point, and > our > call will only affect the first process. > > IOW, to set core scheduling cookies on the helpers, we need to set > them > upfront at the time we spawn the helper. > > IOW, during startup, IIUC, we need to fork a dummy process solely to > call PR_SCHED_CORE_CREATE. Then when forking anything else, whether a > helper, or QEMU itself, we need to pull the cookie from that dummy > process, and then finally kill that dummy process. > Yes. Not pretty, but if forks are involved, that's the solution, I think. An alternative would be to create/pull the cookie in the main process (the one that forks all the helpers), then do fork all helpers, and then "clear" the cookie for it. But I guess that would be even worse... Regards -- Dario Faggioli, Ph.D http://about.me/dario.faggioli Virtualization Software Engineer SUSE Labs, SUSE https://www.suse.com/ ------------------------------------------------------------------- <<This happens because _I_ choose it to happen!>> (Raistlin Majere)
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