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| author | Stephane Eranian <eranian@hpl.hp.com> | 2006-09-26 10:52:28 +0200 |
|---|---|---|
| committer | Andi Kleen <andi@basil.nowhere.org> | 2006-09-26 10:52:28 +0200 |
| commit | d3a4f48d4866b8623ca9adde8ce4e5fde979c132 (patch) | |
| tree | 04413a1f18c6f49688d6008b583b20a287920a0f /include/asm-x86_64/thread_info.h | |
| parent | [PATCH] Clean up asm/smp.h includes (diff) | |
| download | linux-d3a4f48d4866b8623ca9adde8ce4e5fde979c132.tar.xz linux-d3a4f48d4866b8623ca9adde8ce4e5fde979c132.zip | |
[PATCH] x86-64 TIF flags for debug regs and io bitmap in ctxsw
Hello,
Following my discussion with Andi. Here is a patch that introduces
two new TIF flags to simplify the context switch code in __switch_to().
The idea is to minimize the number of cache lines accessed in the common
case, i.e., when neither the debug registers nor the I/O bitmap are used.
This patch covers the x86-64 modifications. A patch for i386 follows.
Changelog:
- add TIF_DEBUG to track when debug registers are active
- add TIF_IO_BITMAP to track when I/O bitmap is used
- modify __switch_to() to use the new TIF flags
<signed-off-by>: eranian@hpl.hp.com
Signed-off-by: Andi Kleen <ak@suse.de>
Diffstat (limited to 'include/asm-x86_64/thread_info.h')
| -rw-r--r-- | include/asm-x86_64/thread_info.h | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/include/asm-x86_64/thread_info.h b/include/asm-x86_64/thread_info.h index 790c512a4369..787a08114b48 100644 --- a/include/asm-x86_64/thread_info.h +++ b/include/asm-x86_64/thread_info.h @@ -120,6 +120,8 @@ static inline struct thread_info *stack_thread_info(void) #define TIF_FORK 18 /* ret_from_fork */ #define TIF_ABI_PENDING 19 #define TIF_MEMDIE 20 +#define TIF_DEBUG 21 /* uses debug registers */ +#define TIF_IO_BITMAP 22 /* uses I/O bitmap */ #define _TIF_SYSCALL_TRACE (1<<TIF_SYSCALL_TRACE) #define _TIF_NOTIFY_RESUME (1<<TIF_NOTIFY_RESUME) @@ -133,6 +135,8 @@ static inline struct thread_info *stack_thread_info(void) #define _TIF_IA32 (1<<TIF_IA32) #define _TIF_FORK (1<<TIF_FORK) #define _TIF_ABI_PENDING (1<<TIF_ABI_PENDING) +#define _TIF_DEBUG (1<<TIF_DEBUG) +#define _TIF_IO_BITMAP (1<<TIF_IO_BITMAP) /* work to do on interrupt/exception return */ #define _TIF_WORK_MASK \ @@ -140,6 +144,9 @@ static inline struct thread_info *stack_thread_info(void) /* work to do on any return to user space */ #define _TIF_ALLWORK_MASK (0x0000FFFF & ~_TIF_SECCOMP) +/* flags to check in __switch_to() */ +#define _TIF_WORK_CTXSW (_TIF_DEBUG|_TIF_IO_BITMAP) + #define PREEMPT_ACTIVE 0x10000000 /* |