From mboxrd@z Thu Jan 1 00:00:00 1970 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 Message-ID: <20161013115712.29517-2-heiko.carstens@de.ibm.com> References: <20161013115712.29517-1-heiko.carstens@de.ibm.com> Return-path: In-Reply-To: <20161013115712.29517-1-heiko.carstens@de.ibm.com> Sender: linux-kernel-owner@vger.kernel.org To: Andy Lutomirski , Peter Zijlstra , Linus Torvalds , Ingo Molnar , "H . Peter Anvin" Cc: Mark Rutland , linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, Martin Schwidefsky List-Id: linux-arch.vger.kernel.org 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 --- 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 #include +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 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:58421 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755522AbcJMTMb (ORCPT ); Thu, 13 Oct 2016 15:12:31 -0400 Received: from pps.filterd (m0098394.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.17/8.16.0.17) with SMTP id u9DBrlIo086564 for ; Thu, 13 Oct 2016 07:57:19 -0400 Received: from e06smtp10.uk.ibm.com (e06smtp10.uk.ibm.com [195.75.94.106]) by mx0a-001b2d01.pphosted.com with ESMTP id 26240wg4n3-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Thu, 13 Oct 2016 07:57:18 -0400 Received: from localhost by e06smtp10.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Thu, 13 Oct 2016 12:57:16 +0100 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 In-Reply-To: <20161013115712.29517-1-heiko.carstens@de.ibm.com> References: <20161013115712.29517-1-heiko.carstens@de.ibm.com> Message-ID: <20161013115712.29517-2-heiko.carstens@de.ibm.com> Sender: linux-arch-owner@vger.kernel.org List-ID: To: Andy Lutomirski , Peter Zijlstra , Linus Torvalds , Ingo Molnar , "H . Peter Anvin" Cc: Mark Rutland , linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, Martin Schwidefsky Message-ID: <20161013115710.TQOnwcCfiTewPjTmb2Opk_ujSLkLqW-re6AmGqkESI0@z> 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 --- 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 #include +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