* Re: [PATCH 1/2] x86: reimplement ___preempt_schedule*() using THUNK helpers
2014-09-04 13:42 ` [PATCH 1/2] " Oleg Nesterov
@ 2014-09-04 16:51 ` Denys Vlasenko
2014-09-04 17:11 ` Oleg Nesterov
2014-09-04 17:12 ` [PATCH v2 " Oleg Nesterov
2014-09-05 0:37 ` [PATCH " Andy Lutomirski
2 siblings, 1 reply; 8+ messages in thread
From: Denys Vlasenko @ 2014-09-04 16:51 UTC (permalink / raw)
To: Oleg Nesterov
Cc: H. Peter Anvin, Andy Lutomirski, Denys Vlasenko, Ingo Molnar,
Peter Zijlstra, X86 ML, Linux Kernel Mailing List
On Thu, Sep 4, 2014 at 3:42 PM, Oleg Nesterov <oleg@redhat.com> wrote:
> -#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
I think THUNK should be thunk_ra here;
or thunk_ra should be renamed to THUNK (like it is in thunk_64.S)
^ permalink raw reply [flat|nested] 8+ messages in thread
* [PATCH v2 1/2] x86: reimplement ___preempt_schedule*() using THUNK helpers
2014-09-04 13:42 ` [PATCH 1/2] " Oleg Nesterov
2014-09-04 16:51 ` Denys Vlasenko
@ 2014-09-04 17:12 ` Oleg Nesterov
2014-09-05 0:37 ` [PATCH " Andy Lutomirski
2 siblings, 0 replies; 8+ messages in thread
From: Oleg Nesterov @ 2014-09-04 17:12 UTC (permalink / raw)
To: H. Peter Anvin
Cc: Andy Lutomirski, Denys Vlasenko, Ingo Molnar, Peter Zijlstra, x86,
linux-kernel
___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>
---
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..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
--
1.5.5.1
^ permalink raw reply related [flat|nested] 8+ messages in thread
* Re: [PATCH 1/2] x86: reimplement ___preempt_schedule*() using THUNK helpers
2014-09-04 13:42 ` [PATCH 1/2] " Oleg Nesterov
2014-09-04 16:51 ` Denys Vlasenko
2014-09-04 17:12 ` [PATCH v2 " Oleg Nesterov
@ 2014-09-05 0:37 ` Andy Lutomirski
2 siblings, 0 replies; 8+ messages in thread
From: Andy Lutomirski @ 2014-09-05 0:37 UTC (permalink / raw)
To: Oleg Nesterov
Cc: H. Peter Anvin, Denys Vlasenko, Ingo Molnar, Peter Zijlstra,
X86 ML, linux-kernel@vger.kernel.org
On Thu, Sep 4, 2014 at 6:42 AM, Oleg Nesterov <oleg@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 <luto@amacapital.net>
>
> Signed-off-by: Oleg Nesterov <oleg@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
^ permalink raw reply [flat|nested] 8+ messages in thread