Messages in this thread | | | Date | Tue, 07 Apr 2015 13:00:48 -0400 | From | Sasha Levin <> | Subject | Re: Hang on large copy_from_user with PREEMPT_NONE |
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On 04/07/2015 10:37 AM, Ingo Molnar wrote: > > * Michal Hocko <mhocko@suse.cz> wrote: > >> On Tue 07-04-15 13:05:31, Ingo Molnar wrote: >>> >>> * Borislav Petkov <bp@alien8.de> wrote: >>> >>>> On Tue, Apr 07, 2015 at 11:31:45AM +0200, Ingo Molnar wrote: >>>>> Would be nice to see the actual kernel .config, as there's a few >>>>> debug features that can slow things down significantly, such as >>>>> CONFIG_KMEMCHECK=y or in some cases CONFIG_DEBUG_PAGEALLOC=y. >>>> >>>> He sent it here: https://lkml.kernel.org/r/55229D7E.6080309@oracle.com >>>> >>>> I'm attaching it again. >>> >>> Thanks. Nothing particularly expensive stands out to me at a quick >>> glance:-/ >> >> Sasha uses KASAN very often and it is enabled here as well. I guess >> this might slow things really down. > > Indeed, that kind of instrumentation might explain the overhead ...
It locks up quickly without KASan as well.
Thanks, Sasha
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