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x86/fpu: Factor out fpu__flush_thread() from flush_thread() 

flush_thread() open codes a lot of FPU internals - create a separate
function for it in fpu/core.c.

Turns out that this does not hurt performance:

   text    data     bss     dec     hex filename
   11843039        1884440 1130496 14857975         e2b6f7 vmlinux.before
   11843039        1884440 1130496 14857975         e2b6f7 vmlinux.after

and since this is a slowpath clarity comes first anyway.

We can reconsider inlining decisions after the FPU code has been cleaned up.

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: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Ingo Molnar 2015-04-22 11:52:13 +02:00
parent 11ad19277e
commit 81683cc827
3 changed files with 19 additions and 13 deletions
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1
arch/x86/include/asm/i387.h
View File

@ -20,6 +20,7 @@ struct user_i387_struct;
extern int fpstate_alloc_init(struct task_struct *curr);
extern void fpstate_init(struct fpu *fpu);
extern void fpu__flush_thread(struct task_struct *tsk);
extern int dump_fpu(struct pt_regs *, struct user_i387_struct *);
extern void math_state_restore(void);

17
arch/x86/kernel/fpu/core.c
View File

@ -227,6 +227,23 @@ static int fpu__unlazy_stopped(struct task_struct *child)
return 0;
}
void fpu__flush_thread(struct task_struct *tsk)
{
if (!use_eager_fpu()) {
/* FPU state will be reallocated lazily at the first use. */
drop_fpu(tsk);
fpstate_free(&tsk->thread.fpu);
} else {
if (!tsk_used_math(tsk)) {
/* kthread execs. TODO: cleanup this horror. */
if (WARN_ON(fpstate_alloc_init(tsk)))
force_sig(SIGKILL, tsk);
user_fpu_begin();
}
restore_init_xstate();
}
}
/*
* The xstateregs_active() routine is the same as the fpregs_active() routine,
* as the "regset->n" for the xstate regset will be updated based on the feature

14
arch/x86/kernel/process.c
View File

@ -146,19 +146,7 @@ void flush_thread(void)
flush_ptrace_hw_breakpoint(tsk);
memset(tsk->thread.tls_array, 0, sizeof(tsk->thread.tls_array));
if (!use_eager_fpu()) {
/* FPU state will be reallocated lazily at the first use. */
drop_fpu(tsk);
fpstate_free(&tsk->thread.fpu);
} else {
if (!tsk_used_math(tsk)) {
/* kthread execs. TODO: cleanup this horror. */
if (WARN_ON(fpstate_alloc_init(tsk)))
force_sig(SIGKILL, tsk);
user_fpu_begin();
}
restore_init_xstate();
}
fpu__flush_thread(tsk);
}
static void hard_disable_TSC(void)