Messages in this thread | | | Date | Thu, 21 Feb 2019 21:40:30 +0000 | From | Wei Yang <> | Subject | Re: [LKP] [driver core] 570d020012: will-it-scale.per_thread_ops -12.2% regression |
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On Thu, Feb 21, 2019 at 10:12:17AM +0100, Greg Kroah-Hartman wrote: >On Thu, Feb 21, 2019 at 04:39:27PM +0800, Wei Yang wrote: >> >>> I don't think this is an issues of struct device. As you said, struct >> >>> device isn't access much during test. Struct device may share slab page >> >>> with some other data structures (signal related, or fd related (as in >> >>> some other test cases)), so that the alignment of these data structures >> >>> are affected, so caused the performance regression. >> >> >> >> But allocation of a structure should always be "properly" aligned, no >> >> matter what something else did in the system as that is what kmalloc >> >> ensures. If not, then we have problems in our memory allocator :) >> >> >> >> So something is odd here, but I don't think that is it... >> > >> >If all these data structure are allocated with kmalloc() instead of >> >kmem_cache_alloc(), then my guessing above seems incorrect ... >> > >> >> Seems we don't have special kmem_cache for device and device_private. > >Nor do we need one :) > >Remember, 'struct device' is included inside lots of other structures >already, it is not very often created "on its own." >
You are right, I get your point.
>thanks, > >greg k-h
-- Wei Yang Help you, Help me
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