diff options
| author | Vineet Gupta | 2013-11-12 15:08:46 -0800 |
|---|---|---|
| committer | Linus Torvalds | 2013-11-13 12:09:13 +0900 |
| commit | c375f15a434db1867cb004bafba92aba739e4e39 (patch) | |
| tree | 419ff5ddf823f9b43d95d1fc6345611989364cde /arch/x86/include | |
| parent | 616c05d110bb4ef8203f49c9d2476874077c2f6a (diff) | |
x86: move fpu_counter into ARCH specific thread_struct
Only a couple of arches (sh/x86) use fpu_counter in task_struct so it can
be moved out into ARCH specific thread_struct, reducing the size of
task_struct for other arches.
Compile tested i386_defconfig + gcc 4.7.3
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Cc: Paul Mundt <paul.mundt@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/x86/include')
| -rw-r--r-- | arch/x86/include/asm/fpu-internal.h | 10 | ||||
| -rw-r--r-- | arch/x86/include/asm/processor.h | 9 |
2 files changed, 14 insertions, 5 deletions
diff --git a/arch/x86/include/asm/fpu-internal.h b/arch/x86/include/asm/fpu-internal.h index 4d0bda7b11e3..c49a613c6452 100644 --- a/arch/x86/include/asm/fpu-internal.h +++ b/arch/x86/include/asm/fpu-internal.h @@ -365,7 +365,7 @@ static inline void drop_fpu(struct task_struct *tsk) * Forget coprocessor state.. */ preempt_disable(); - tsk->fpu_counter = 0; + tsk->thread.fpu_counter = 0; __drop_fpu(tsk); clear_used_math(); preempt_enable(); @@ -424,7 +424,7 @@ static inline fpu_switch_t switch_fpu_prepare(struct task_struct *old, struct ta * or if the past 5 consecutive context-switches used math. */ fpu.preload = tsk_used_math(new) && (use_eager_fpu() || - new->fpu_counter > 5); + new->thread.fpu_counter > 5); if (__thread_has_fpu(old)) { if (!__save_init_fpu(old)) cpu = ~0; @@ -433,16 +433,16 @@ static inline fpu_switch_t switch_fpu_prepare(struct task_struct *old, struct ta /* Don't change CR0.TS if we just switch! */ if (fpu.preload) { - new->fpu_counter++; + new->thread.fpu_counter++; __thread_set_has_fpu(new); prefetch(new->thread.fpu.state); } else if (!use_eager_fpu()) stts(); } else { - old->fpu_counter = 0; + old->thread.fpu_counter = 0; old->thread.fpu.last_cpu = ~0; if (fpu.preload) { - new->fpu_counter++; + new->thread.fpu_counter++; if (!use_eager_fpu() && fpu_lazy_restore(new, cpu)) fpu.preload = 0; else diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h index 987c75ecc334..7b034a4057f9 100644 --- a/arch/x86/include/asm/processor.h +++ b/arch/x86/include/asm/processor.h @@ -488,6 +488,15 @@ struct thread_struct { unsigned long iopl; /* Max allowed port in the bitmap, in bytes: */ unsigned io_bitmap_max; + /* + * fpu_counter contains the number of consecutive context switches + * that the FPU is used. If this is over a threshold, the lazy fpu + * saving becomes unlazy to save the trap. This is an unsigned char + * so that after 256 times the counter wraps and the behavior turns + * lazy again; this to deal with bursty apps that only use FPU for + * a short time + */ + unsigned char fpu_counter; }; /* |