diff options
| author | Oleg Nesterov <oleg@redhat.com> | 2014-09-21 20:41:53 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2014-09-24 15:15:38 +0200 |
| commit | 0ad6e3c5199be12c9745da8f8b9e3c9f8066c235 (patch) | |
| tree | 581d938c3bf976c54a95b2fd6030c232b7885031 /arch | |
| parent | f3670394c29ff3730638762c1760fd2f624e6d7b (diff) | |
| download | linux-0ad6e3c5199be12c9745da8f8b9e3c9f8066c235.tar.bz2 | |
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 <oleg@redhat.com>
Reviewed-by: Andy Lutomirski <luto@amacapital.net>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20140921184153.GA23727@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/kernel/Makefile | 2 | ||||
| -rw-r--r-- | arch/x86/kernel/preempt.S | 25 | ||||
| -rw-r--r-- | arch/x86/lib/thunk_32.S | 20 | ||||
| -rw-r--r-- | 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 ada2e2d6be3e..8f1e77440b2b 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 ca7f0d58a87d..000000000000 --- 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 28f85c916712..e9acf5f4fc92 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 92d9feaff42b..b30b5ebd614a 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 |