Messages in this thread Patch in this message | | | Date | Mon, 4 Aug 2014 19:05:19 +0200 | From | Oleg Nesterov <> | Subject | [PATCH?] x86: reimplement ___preempt_schedule*() using THUNK helpers |
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On 08/04, Denys Vlasenko wrote: > > --- a/arch/x86/kernel/preempt.S > +++ b/arch/x86/kernel/preempt.S > @@ -6,9 +6,13 @@ > > ENTRY(___preempt_schedule) > CFI_STARTPROC > - SAVE_ALL > + ALLOC_PTREGS_ON_STACK > + SAVE_C_REGS > + SAVE_EXTRA_REGS > call preempt_schedule > - RESTORE_ALL > + RESTORE_EXTRA_REGS > + RESTORE_C_REGS > + REMOVE_PTREGS_FROM_STACK > ret > CFI_ENDPROC > > @@ -16,9 +20,13 @@ ENTRY(___preempt_schedule) > > ENTRY(___preempt_schedule_context) > CFI_STARTPROC > - SAVE_ALL > + ALLOC_PTREGS_ON_STACK > + SAVE_C_REGS > + SAVE_EXTRA_REGS > call preempt_schedule_context > - RESTORE_ALL > + RESTORE_EXTRA_REGS > + RESTORE_C_REGS > + REMOVE_PTREGS_FROM_STACK > ret > CFI_ENDPROC
Hmm. This part looks fine, but with or without this patch this all is suboptimal, we do not need SAVE_ALL unless I missed something. Can't we simply kill preempt.S ?
Peter, what do you think?
Oleg.
---------------------------------------------------------------------------- Subject: [PATCH] x86: reimplement ___preempt_schedule*() using THUNK helpers
diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile index 047f9ff..3f5d657 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..dc2b8fd 100644 --- a/arch/x86/lib/thunk_32.S +++ b/arch/x86/lib/thunk_32.S @@ -7,7 +7,6 @@ #include <linux/linkage.h> #include <asm/asm.h> -#ifdef CONFIG_TRACE_IRQFLAGS /* put return address in eax (arg1) */ .macro thunk_ra name,func .globl \name @@ -25,6 +24,15 @@ _ASM_NOKPROBE(\name) .endm +#ifdef CONFIG_TRACE_IRQFLAGS thunk_ra trace_hardirqs_on_thunk,trace_hardirqs_on_caller thunk_ra trace_hardirqs_off_thunk,trace_hardirqs_off_caller #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
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