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 <b...@alien8.de>
Cc: Andy Lutomirski <l...@amacapital.net>
Cc: Dave Hansen <dave.han...@linux.intel.com>
Cc: Fenghua Yu <fenghua...@intel.com>
Cc: H. Peter Anvin <h...@zytor.com>
Cc: Linus Torvalds <torva...@linux-foundation.org>
Cc: Oleg Nesterov <o...@redhat.com>
Cc: Thomas Gleixner <t...@linutronix.de>
Signed-off-by: Ingo Molnar <mi...@kernel.org>
---
arch/x86/include/asm/i387.h | 1 +
arch/x86/kernel/fpu/core.c | 15 +++++++++++++++
arch/x86/kernel/process.c | 12 +-----------
3 files changed, 17 insertions(+), 11 deletions(-)
diff --git a/arch/x86/include/asm/i387.h b/arch/x86/include/asm/i387.h
index 6552a16e0e38..d6fc84440b73 100644
--- a/arch/x86/include/asm/i387.h
+++ b/arch/x86/include/asm/i387.h
@@ -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);
diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c
index 9211582f5d3f..d31812d973a3 100644
--- a/arch/x86/kernel/fpu/core.c
+++ b/arch/x86/kernel/fpu/core.c
@@ -227,6 +227,21 @@ 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 (!used_math()) {
+ /* 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
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index a9bff373f7eb..0a4c35c3fb2f 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -146,17 +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 (!used_math()) {
- /* 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)
--
2.1.0
--
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