[PATCH] x86: Change thread_info's flag field back to 32 bits

[PATCH] x86: Change thread_info's flag field back to 32 bits

[Joe Korty]

Change x86_64's thread_info 'flags' field back to __u32.

This was changed to 'unsigned long' when the thread_info*.h
for i386 and x86_64 were merged.  Change it back.  We can
do this as only 27 bits of 'flags' are actually used.

This change actually packs down thread_info by 64 bits:
32 bits are saved by the smaller flags, and 32 bits are
saved by the following 'mm_segment_t field' becoming
naturally 64-bit aligned.

Signed-off-by: Joe Korty <joe.korty@ccur.com>

Index: 2.6.28-rc7/arch/x86/include/asm/thread_info.h
===================================================================
--- 2.6.28-rc7.orig/arch/x86/include/asm/thread_info.h	2008-12-03 17:53:10.000000000 -0500
+++ 2.6.28-rc7/arch/x86/include/asm/thread_info.h	2008-12-03 18:31:40.000000000 -0500
@@ -24,7 +24,7 @@
 struct thread_info {
 	struct task_struct	*task;		/* main task structure */
 	struct exec_domain	*exec_domain;	/* execution domain */
-	unsigned long		flags;		/* low level flags */
+	__u32			flags;		/* low level flags */
 	__u32			status;		/* thread synchronous flags */
 	__u32			cpu;		/* current CPU */
 	int			preempt_count;	/* 0 => preemptable,

Re: [PATCH] x86: Change thread_info's flag field back to 32 bits

[Ingo Molnar]

* Joe Korty <joe.korty@ccur.com> wrote:

> Change x86_64's thread_info 'flags' field back to __u32.
> 
> This was changed to 'unsigned long' when the thread_info*.h
> for i386 and x86_64 were merged.  Change it back.  We can
> do this as only 27 bits of 'flags' are actually used.
> 
> This change actually packs down thread_info by 64 bits:
> 32 bits are saved by the smaller flags, and 32 bits are
> saved by the following 'mm_segment_t field' becoming
> naturally 64-bit aligned.
> 
> Signed-off-by: Joe Korty <joe.korty@ccur.com>

applied, thanks Joe!

	Ingo