Messages in this thread | | | Date | Fri, 5 Jun 2020 10:10:28 +0200 | From | Peter Zijlstra <> | Subject | Re: [RFC][PATCH 7/7] sched: Replace rq::wake_list |
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On Thu, Jun 04, 2020 at 07:18:37AM -0700, Guenter Roeck wrote: > On Tue, May 26, 2020 at 06:11:04PM +0200, Peter Zijlstra wrote:
> > + BUILD_BUG_ON(offsetof(struct task_struct, wake_entry_type) - offsetof(struct task_struct, wake_entry) != > > + offsetof(struct __call_single_data, flags) - offsetof(struct __call_single_data, llist)); > > + > > There is no guarantee in C that > > type1 a; > type2 b; > > in two different data structures means that offsetof(b) - offsetof(a) > is the same in both data structures unless attributes such as > __attribute__((__packed__)) are used.
Do tell more; the alignment requirements and size of the types remains the same, this resulting in different layout is unlikely.
I found this excellent quote on Hacker News this morning:
"I think the attitude of compiler writers is a good reason to fix the spec so they can't keep ratfucking developers trying to get work done."
> As result, this does and will cause a variety of build errors depending > on the compiler version and compile flags.
The only thing I can think of that's actually a problem is that retarded struct randomization stuff.
Anyway, I'll move cleaning it up a little higher on the todo list.
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