Messages in this thread |  | | Date | Thu, 20 Oct 2016 10:33:53 +0100 | From | Mark Rutland <> | Subject | Re: [PATCH 1/3] sched/core,x86: make struct thread_info arch specific again |
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On Thu, Oct 20, 2016 at 08:40:45AM +0200, Ingo Molnar wrote: > > * Andy Lutomirski <luto@amacapital.net> wrote: > > > On Wed, Oct 19, 2016 at 11:28 AM, Mark Rutland <mark.rutland@arm.com> wrote: > > > From: Heiko Carstens <heiko.carstens@de.ibm.com> > > > > > > commit c65eacbe290b ("sched/core: Allow putting thread_info into > > > task_struct") made struct thread_info a generic struct with only a > > > single flags member if THREAD_INFO_IN_TASK_STRUCT is selected. > > > > > > This change however seems to be quite x86 centric, since at least the > > > generic preemption code (asm-generic/preempt.h) assumes that struct > > > thread_info also has a preempt_count member, which apparently was not > > > true for x86. > > > > > > We could add a bit more ifdefs to solve this problem too, but it seems > > > to be much simpler to make struct thread_info arch specific > > > again. This also makes the conversion to THREAD_INFO_IN_TASK_STRUCT a > > > bit easier for architectures that have a couple of arch specific stuff > > > in their thread_info definition. > > > > > > The arch specific stuff _could_ be moved to thread_struct. However > > > keeping them in thread_info makes it easier: accessing thread_info > > > members is simple, since it is at the beginning of the task_struct, > > > while the thread_struct is at the end. At least on s390 the offsets > > > needed to access members of the thread_struct (with task_struct as > > > base) are too large for various asm instructions. This is not a > > > problem when keeping these members within thread_info. > > > > Acked-by: Andy Lutomirski <luto@kernel.org> > > > > Ingo, there's a (somewhat weak) argument for sending this via > > tip/urgent: it doesn't change generated code at all, and I think it > > will avoid a silly depedency or possible conflict for the next merge > > window, since both arm64 and s390 are going to need it. > > Can certainly do it if this is the final version of the patch. Mark?
Yes; this is the final version of this patch.
I can rebase the other two core patches atop, assuming this goes in for a v4.9-rc* tag soon.
Thanks, Mark.
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