Commit-ID: 0ad6e3c5199be12c9745da8f8b9e3c9f8066c235 Gitweb: http://git.kernel.org/tip/0ad6e3c5199be12c9745da8f8b9e3c9f8066c235 Author: Oleg Nesterov <o...@redhat.com> AuthorDate: Sun, 21 Sep 2014 20:41:53 +0200 Committer: Ingo Molnar <mi...@kernel.org> CommitDate: Wed, 24 Sep 2014 15:15:38 +0200
x86: Speed up ___preempt_schedule*() by using THUNK helpers ___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. Signed-off-by: Oleg Nesterov <o...@redhat.com> Reviewed-by: Andy Lutomirski <l...@amacapital.net> Cc: Denys Vlasenko <dvlas...@redhat.com> Cc: Peter Zijlstra <pet...@infradead.org> Cc: Linus Torvalds <torva...@linux-foundation.org> Link: http://lkml.kernel.org/r/20140921184153.ga23...@redhat.com Signed-off-by: Ingo Molnar <mi...@kernel.org> --- 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(-) diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile index ada2e2d..8f1e774 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 28f85c91..e9acf5f 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 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 trace_hardirqs_on_thunk,trace_hardirqs_on_caller,1 + THUNK 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 -- 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/
