Hello. On Mon, Jun 24, 2024 at 09:09:40PM GMT, Li Lingfeng <lilingfeng@xxxxxxxxxxxxxxx> wrote: > From: Li Lingfeng <lilingfeng3@xxxxxxxxxx> > > When a process migrates to another cgroup and the original cgroup is deleted, > the restrictions of throttled bios cannot be removed. If the restrictions > are set too low, it will take a long time to complete these bios. When pd_offline_fn is called because of disk going away, it makes sense to cancel the bios. However, when pd_offline_fn is called due to cgroup removal (with possibly surviving originating process), wouldn't bio cancelling lead to loss of data? Aha, it wouldn't -- the purpose of the function is to "flush" throttled bios (in the original patch they'd immediately fail, here they the IO operation may succeed). Is that correct? (Wouldn't there be a more descriptive name than tg_cancel_bios then?) And if a user is allowed to remove cgroup and use this to bypass the throttling, they also must have permissions to migrate away from the cgroup (and consistent config would thus allow them to change the limit too), therefore this doesn't allow bypassing the throttling limit. If you agree, could you please add the explanation to commit message too? Thanks, Michal
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