diff options
| -rw-r--r-- | arch/i386/kernel/process.c | 12 | ||||
| -rw-r--r-- | arch/i386/kernel/traps.c | 3 | ||||
| -rw-r--r-- | include/asm-i386/i387.h | 5 |
3 files changed, 18 insertions, 2 deletions
diff --git a/arch/i386/kernel/process.c b/arch/i386/kernel/process.c index dd53c58f64f..ae924c416b6 100644 --- a/arch/i386/kernel/process.c +++ b/arch/i386/kernel/process.c @@ -648,6 +648,11 @@ struct task_struct fastcall * __switch_to(struct task_struct *prev_p, struct tas __unlazy_fpu(prev_p); + + /* we're going to use this soon, after a few expensive things */ + if (next_p->fpu_counter > 5) + prefetch(&next->i387.fxsave); + /* * Reload esp0. */ @@ -697,6 +702,13 @@ struct task_struct fastcall * __switch_to(struct task_struct *prev_p, struct tas disable_tsc(prev_p, next_p); + /* If the task has used fpu the last 5 timeslices, just do a full + * restore of the math state immediately to avoid the trap; the + * chances of needing FPU soon are obviously high now + */ + if (next_p->fpu_counter > 5) + math_state_restore(); + return prev_p; } diff --git a/arch/i386/kernel/traps.c b/arch/i386/kernel/traps.c index f9bb1f89d68..4a6fa2837df 100644 --- a/arch/i386/kernel/traps.c +++ b/arch/i386/kernel/traps.c @@ -1118,7 +1118,7 @@ fastcall unsigned long patch_espfix_desc(unsigned long uesp, * Must be called with kernel preemption disabled (in this case, * local interrupts are disabled at the call-site in entry.S). */ -asmlinkage void math_state_restore(struct pt_regs regs) +asmlinkage void math_state_restore(void) { struct thread_info *thread = current_thread_info(); struct task_struct *tsk = thread->task; @@ -1128,6 +1128,7 @@ asmlinkage void math_state_restore(struct pt_regs regs) init_fpu(tsk); restore_fpu(tsk); thread->status |= TS_USEDFPU; /* So we fnsave on switch_to() */ + tsk->fpu_counter++; } #ifndef CONFIG_MATH_EMULATION diff --git a/include/asm-i386/i387.h b/include/asm-i386/i387.h index bc1d6edae1e..434936c732d 100644 --- a/include/asm-i386/i387.h +++ b/include/asm-i386/i387.h @@ -76,7 +76,9 @@ static inline void __save_init_fpu( struct task_struct *tsk ) #define __unlazy_fpu( tsk ) do { \ if (task_thread_info(tsk)->status & TS_USEDFPU) \ - save_init_fpu( tsk ); \ + save_init_fpu( tsk ); \ + else \ + tsk->fpu_counter = 0; \ } while (0) #define __clear_fpu( tsk ) \ @@ -118,6 +120,7 @@ static inline void save_init_fpu( struct task_struct *tsk ) extern unsigned short get_fpu_cwd( struct task_struct *tsk ); extern unsigned short get_fpu_swd( struct task_struct *tsk ); extern unsigned short get_fpu_mxcsr( struct task_struct *tsk ); +extern asmlinkage void math_state_restore(void); /* * Signal frame handlers... |