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_64.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_64.c')
| -rw-r--r-- | arch/x86/kernel/traps_64.c | 19 |
1 files changed, 16 insertions, 3 deletions
diff --git a/arch/x86/kernel/traps_64.c b/arch/x86/kernel/traps_64.c index dc0cb497eec3..adff76ea97c4 100644 --- a/arch/x86/kernel/traps_64.c +++ b/arch/x86/kernel/traps_64.c @@ -1124,10 +1124,23 @@ asmlinkage void __attribute__((weak)) mce_threshold_interrupt(void) asmlinkage void math_state_restore(void) { struct task_struct *me = current; - clts(); /* Allow maths ops (or we recurse) */ - if (!used_math()) - init_fpu(me); + if (!used_math()) { + local_irq_enable(); + /* + * does a slab alloc which can sleep + */ + if (init_fpu(me)) { + /* + * ran out of memory! + */ + do_group_exit(SIGKILL); + return; + } + local_irq_disable(); + } + + clts(); /* Allow maths ops (or we recurse) */ restore_fpu_checking(&me->thread.xstate->fxsave); task_thread_info(me)->status |= TS_USEDFPU; me->fpu_counter++; |