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." thanks, greg k-h
