Messages in this thread Patch in this message | | | From | Heiko Carstens <> | Subject | [PATCH 1/3] sched/core,x86: make struct thread_info arch specific again | Date | Thu, 13 Oct 2016 13:57:10 +0200 |
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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.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> --- arch/x86/include/asm/thread_info.h | 9 +++++++++ include/linux/thread_info.h | 11 ----------- 2 files changed, 9 insertions(+), 11 deletions(-)
diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h index 2aaca53c0974..ad6f5eb07a95 100644 --- a/arch/x86/include/asm/thread_info.h +++ b/arch/x86/include/asm/thread_info.h @@ -52,6 +52,15 @@ struct task_struct; #include <asm/cpufeature.h> #include <linux/atomic.h> +struct thread_info { + unsigned long flags; /* low level flags */ +}; + +#define INIT_THREAD_INFO(tsk) \ +{ \ + .flags = 0, \ +} + #define init_stack (init_thread_union.stack) #else /* !__ASSEMBLY__ */ diff --git a/include/linux/thread_info.h b/include/linux/thread_info.h index 45f004e9cc59..2873baf5372a 100644 --- a/include/linux/thread_info.h +++ b/include/linux/thread_info.h @@ -14,17 +14,6 @@ struct timespec; struct compat_timespec; #ifdef CONFIG_THREAD_INFO_IN_TASK -struct thread_info { - unsigned long flags; /* low level flags */ -}; - -#define INIT_THREAD_INFO(tsk) \ -{ \ - .flags = 0, \ -} -#endif - -#ifdef CONFIG_THREAD_INFO_IN_TASK #define current_thread_info() ((struct thread_info *)current) #endif -- 2.8.4
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