On Thu, Sep 4, 2014 at 6:42 AM, Oleg Nesterov <o...@redhat.com> wrote: > > ___preempt_schedule() does SAVE_ALL/RESTORE_ALL but this is suboptimal, > we do not need to save/restore the callee-saved register. And we already > have arch/x86/lib/thunk_*.S which implements the similar asm wrappers, > so it makes sense to redefine ___preempt_schedule() as "THUNK ..." and > remove preempt.S altogether.
Reviewed-by: Andy Lutomirski <l...@amacapital.net> > > Signed-off-by: Oleg Nesterov <o...@redhat.com> > --- > arch/x86/kernel/Makefile | 2 -- > arch/x86/kernel/preempt.S | 25 ------------------------- > arch/x86/lib/thunk_32.S | 20 ++++++++++++++++---- > arch/x86/lib/thunk_64.S | 7 +++++++ > 4 files changed, 23 insertions(+), 31 deletions(-) > delete mode 100644 arch/x86/kernel/preempt.S > > diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile > index b5ea75c..58cf60b 100644 > --- a/arch/x86/kernel/Makefile > +++ b/arch/x86/kernel/Makefile > @@ -39,8 +39,6 @@ obj-y += tsc.o tsc_msr.o io_delay.o rtc.o > obj-y += pci-iommu_table.o > obj-y += resource.o > > -obj-$(CONFIG_PREEMPT) += preempt.o > - > obj-y += process.o > obj-y += i387.o xsave.o > obj-y += ptrace.o > diff --git a/arch/x86/kernel/preempt.S b/arch/x86/kernel/preempt.S > deleted file mode 100644 > index ca7f0d5..0000000 > --- a/arch/x86/kernel/preempt.S > +++ /dev/null > @@ -1,25 +0,0 @@ > - > -#include <linux/linkage.h> > -#include <asm/dwarf2.h> > -#include <asm/asm.h> > -#include <asm/calling.h> > - > -ENTRY(___preempt_schedule) > - CFI_STARTPROC > - SAVE_ALL > - call preempt_schedule > - RESTORE_ALL > - ret > - CFI_ENDPROC > - > -#ifdef CONFIG_CONTEXT_TRACKING > - > -ENTRY(___preempt_schedule_context) > - CFI_STARTPROC > - SAVE_ALL > - call preempt_schedule_context > - RESTORE_ALL > - ret > - CFI_ENDPROC > - > -#endif > diff --git a/arch/x86/lib/thunk_32.S b/arch/x86/lib/thunk_32.S > index 28f85c9..7f1641a 100644 > --- a/arch/x86/lib/thunk_32.S > +++ b/arch/x86/lib/thunk_32.S > @@ -7,16 +7,19 @@ > #include <linux/linkage.h> > #include <asm/asm.h> > > -#ifdef CONFIG_TRACE_IRQFLAGS > /* put return address in eax (arg1) */ > - .macro thunk_ra name,func > + .macro thunk_ra name, func, put_ret_addr_in_eax=0 > .globl \name > \name: > pushl %eax > pushl %ecx > pushl %edx > + > + .if \put_ret_addr_in_eax > /* Place EIP in the arg1 */ > movl 3*4(%esp), %eax > + .endif > + > call \func > popl %edx > popl %ecx > @@ -25,6 +28,15 @@ > _ASM_NOKPROBE(\name) > .endm > > - thunk_ra trace_hardirqs_on_thunk,trace_hardirqs_on_caller > - thunk_ra trace_hardirqs_off_thunk,trace_hardirqs_off_caller > +#ifdef CONFIG_TRACE_IRQFLAGS > + thunk_ra trace_hardirqs_on_thunk,trace_hardirqs_on_caller,1 > + thunk_ra trace_hardirqs_off_thunk,trace_hardirqs_off_caller,1 > +#endif > + > +#ifdef CONFIG_PREEMPT > + THUNK ___preempt_schedule, preempt_schedule > +#ifdef CONFIG_CONTEXT_TRACKING > + THUNK ___preempt_schedule_context, preempt_schedule_context > #endif > +#endif > + > diff --git a/arch/x86/lib/thunk_64.S b/arch/x86/lib/thunk_64.S > index 92d9fea..b30b5eb 100644 > --- a/arch/x86/lib/thunk_64.S > +++ b/arch/x86/lib/thunk_64.S > @@ -38,6 +38,13 @@ > THUNK lockdep_sys_exit_thunk,lockdep_sys_exit > #endif > > +#ifdef CONFIG_PREEMPT > + THUNK ___preempt_schedule, preempt_schedule > +#ifdef CONFIG_CONTEXT_TRACKING > + THUNK ___preempt_schedule_context, preempt_schedule_context > +#endif > +#endif > + > /* SAVE_ARGS below is used only for the .cfi directives it contains. > */ > CFI_STARTPROC > SAVE_ARGS > -- > 1.5.5.1 > > -- Andy Lutomirski AMA Capital Management, LLC -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
