diff options
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86_64/kernel/process.c | 10 | ||||
| -rw-r--r-- | arch/x86_64/kernel/traps.c | 1 |
2 files changed, 11 insertions, 0 deletions
diff --git a/arch/x86_64/kernel/process.c b/arch/x86_64/kernel/process.c index 6fbd19564e4ecc..9e9a70e50c72ae 100644 --- a/arch/x86_64/kernel/process.c +++ b/arch/x86_64/kernel/process.c @@ -552,6 +552,10 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p) int cpu = smp_processor_id(); struct tss_struct *tss = &per_cpu(init_tss, cpu); + /* we're going to use this soon, after a few expensive things */ + if (next_p->fpu_counter>5) + prefetch(&next->i387.fxsave); + /* * Reload esp0, LDT and the page table pointer: */ @@ -629,6 +633,12 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p) || test_tsk_thread_flag(prev_p, TIF_IO_BITMAP)) __switch_to_xtra(prev_p, next_p, tss); + /* 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/x86_64/kernel/traps.c b/arch/x86_64/kernel/traps.c index 28e53342f294f2..ffc40cff1e07f5 100644 --- a/arch/x86_64/kernel/traps.c +++ b/arch/x86_64/kernel/traps.c @@ -1136,6 +1136,7 @@ asmlinkage void math_state_restore(void) init_fpu(me); restore_fpu_checking(&me->thread.i387.fxsave); task_thread_info(me)->status |= TS_USEDFPU; + me->fpu_counter++; } void __init trap_init(void) |