[PATCH 027/208] x86/fpu: Remove the free_thread_xstate() complication

Ingo Molnar
2015-05-05T17:00:57Z

Use fpstate_free() directly to manage FPU state.

Only process.c was using this method, so this is a speedup as well,
as it removes the extra function call and related clobbers.

Reviewed-by: Borislav Petkov <bp@alien8.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/include/asm/processor.h | 1 -
arch/x86/kernel/process.c | 9 ++-------
2 files changed, 2 insertions(+), 8 deletions(-)

diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index 6b75c4b927ec..fef8db024ece 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -362,7 +362,6 @@ DECLARE_PER_CPU(struct irq_stack *, softirq_stack);
#endif /* X86_64 */

extern unsigned int xstate_size;
-extern void free_thread_xstate(struct task_struct *);
extern struct kmem_cache *task_xstate_cachep;

struct perf_event;
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index 5daa6547fdc7..a9bff373f7eb 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -99,14 +99,9 @@ int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
return 0;
}

-void free_thread_xstate(struct task_struct *tsk)
-{
- fpstate_free(&tsk->thread.fpu);
-}
-
void arch_release_task_struct(struct task_struct *tsk)
{
- free_thread_xstate(tsk);
+ fpstate_free(&tsk->thread.fpu);
}

void arch_task_cache_init(void)
@@ -154,7 +149,7 @@ void flush_thread(void)
if (!use_eager_fpu()) {
/* FPU state will be reallocated lazily at the first use. */
drop_fpu(tsk);
- free_thread_xstate(tsk);
+ fpstate_free(&tsk->thread.fpu);
} else if (!used_math()) {
/* kthread execs. TODO: cleanup this horror. */
if (WARN_ON(fpstate_alloc_init(tsk)))
--
2.1.0