diff options
| author | Suresh Siddha <suresh.b.siddha@intel.com> | 2008-03-10 15:28:05 -0700 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2008-04-19 19:19:55 +0200 |
| commit | aa283f49276e7d840a40fb01eee6de97eaa7e012 (patch) | |
| tree | b17b134b174666e482b1a8ad486436a3d5cdb83e /arch/x86/kernel/traps_32.c | |
| parent | 61c4628b538608c1a85211ed8438136adfeb9a95 (diff) | |
x86, fpu: lazy allocation of FPU area - v5
Only allocate the FPU area when the application actually uses FPU, i.e., in the
first lazy FPU trap. This could save memory for non-fpu using apps.
for example: on my system after boot, there are around 300 processes, with
only 17 using FPU.
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'arch/x86/kernel/traps_32.c')
| -rw-r--r-- | arch/x86/kernel/traps_32.c | 17 |
1 files changed, 15 insertions, 2 deletions
diff --git a/arch/x86/kernel/traps_32.c b/arch/x86/kernel/traps_32.c index 8d136a73ce8..471e694d671 100644 --- a/arch/x86/kernel/traps_32.c +++ b/arch/x86/kernel/traps_32.c @@ -1148,9 +1148,22 @@ asmlinkage void math_state_restore(void) struct thread_info *thread = current_thread_info(); struct task_struct *tsk = thread->task; + if (!tsk_used_math(tsk)) { + local_irq_enable(); + /* + * does a slab alloc which can sleep + */ + if (init_fpu(tsk)) { + /* + * ran out of memory! + */ + do_group_exit(SIGKILL); + return; + } + local_irq_disable(); + } + clts(); /* Allow maths ops (or we recurse) */ - if (!tsk_used_math(tsk)) - init_fpu(tsk); restore_fpu(tsk); thread->status |= TS_USEDFPU; /* So we fnsave on switch_to() */ tsk->fpu_counter++; |