Messages in this thread | | | Subject | Re: [PATCH RFC] nohz,blk-mq: do not create blk-mq workqueues on nohz dedicated CPUs | From | Mike Galbraith <> | Date | Sun, 05 Apr 2015 07:31:59 +0200 |
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On Tue, 2015-03-31 at 10:27 -0400, Rik van Riel wrote: > CPUs with nohz_full do not want disruption from timer interrupts, > or other random system things. This includes block mq work. > > There is another issue with block mq vs. realtime tasks that run > 100% of the time, which is not uncommon on systems that have CPUs > dedicated to real time use with isolcpus= and nohz_full= > > Specifically, on systems like that, a block work item may never > get to run, which could lead to filesystems getting stuck forever.
What reason is there to run a compute hog as RT if it's the only task on an isolated core? In an RT kernel, PI may be a reason, but if a task is so critical that it needs bare metal, it had better not be.
-Mike
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