From: Andi Kleen <andi@firstfloor.org>
To: linux-kernel@vger.kernel.org
Cc: x86@kernel.org, mingo@kernel.org, torvalds@linux-foundation.org,
Andi Kleen <ak@linux.intel.com>
Subject: [PATCH 08/13] x86: Move cond_resched into the out of line put_user code
Date: Fri, 9 Aug 2013 16:04:15 -0700 [thread overview]
Message-ID: <1376089460-5459-9-git-send-email-andi@firstfloor.org> (raw)
In-Reply-To: <1376089460-5459-1-git-send-email-andi@firstfloor.org>
From: Andi Kleen <ak@linux.intel.com>
CONFIG_PREEMPT_VOLUNTARY kernels always do a cond_resched in put_user().
Currently this is done in the caller and in a inefficient way (multiple
function calls to decide to do nothing). Move the reschedule check
into the low level functions instead, where it can be merged cheaply
with the address limit check.
For the DEBUG_SLEEP case we still do the call in the caller.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
---
arch/x86/include/asm/uaccess.h | 2 +-
arch/x86/lib/putuser.S | 12 +++++++++++-
arch/x86/lib/user-common.h | 12 ++++++++++++
3 files changed, 24 insertions(+), 2 deletions(-)
create mode 100644 arch/x86/lib/user-common.h
diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h
index 8fa3bd6..6cbe976 100644
--- a/arch/x86/include/asm/uaccess.h
+++ b/arch/x86/include/asm/uaccess.h
@@ -246,7 +246,7 @@ extern void __put_user_8(void);
int __ret_pu; \
__typeof__(*(ptr)) __pu_val; \
__chk_user_ptr(ptr); \
- might_fault(); \
+ might_fault_debug_only(); \
__pu_val = x; \
switch (sizeof(*(ptr))) { \
case 1: \
diff --git a/arch/x86/lib/putuser.S b/arch/x86/lib/putuser.S
index fc6ba17..9ba7f52 100644
--- a/arch/x86/lib/putuser.S
+++ b/arch/x86/lib/putuser.S
@@ -16,6 +16,8 @@
#include <asm/errno.h>
#include <asm/asm.h>
#include <asm/smap.h>
+#include <asm/calling.h>
+#include "user-common.h"
/*
@@ -31,7 +33,7 @@
*/
#define ENTER CFI_STARTPROC ; \
- GET_THREAD_INFO(%_ASM_BX)
+ GET_THREAD_AND_SCHEDULE %_ASM_BX
#define EXIT ASM_CLAC ; \
ret ; \
CFI_ENDPROC
@@ -99,3 +101,11 @@ END(bad_put_user)
#ifdef CONFIG_X86_32
_ASM_EXTABLE(5b,bad_put_user)
#endif
+
+ENTRY(user_schedule)
+ CFI_STARTPROC
+ SAVE_ALL
+ call _cond_resched
+ RESTORE_ALL
+ ret
+ CFI_ENDPROC
diff --git a/arch/x86/lib/user-common.h b/arch/x86/lib/user-common.h
new file mode 100644
index 0000000..d61cd1a
--- /dev/null
+++ b/arch/x86/lib/user-common.h
@@ -0,0 +1,12 @@
+ .macro GET_THREAD_AND_SCHEDULE reg
+ GET_THREAD_INFO(\reg)
+#ifdef CONFIG_PREEMPT_VOLUNTARY
+ testl $_TIF_NEED_RESCHED,TI_flags(\reg)
+ jnz 1f
+2:
+ .section .fixup,"ax"
+1: call user_schedule
+ jmp 2b
+ .previous
+#endif
+ .endm
--
1.8.3.1
next prev parent reply other threads:[~2013-08-09 23:06 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-08-09 23:04 Re-tune x86 uaccess code for PREEMPT_VOLUNTARY Andi Kleen
2013-08-09 23:04 ` [PATCH 01/13] x86: Add 1/2/4/8 byte optimization to 64bit __copy_{from,to}_user_inatomic Andi Kleen
2013-08-09 23:04 ` [PATCH 02/13] x86: Include linux/sched.h in asm/uaccess.h Andi Kleen
2013-08-09 23:04 ` [PATCH 03/13] tree-sweep: Include linux/sched.h for might_sleep users Andi Kleen
2013-08-09 23:04 ` [PATCH 04/13] Move might_sleep and friends from kernel.h to sched.h Andi Kleen
2013-08-09 23:04 ` [PATCH 05/13] sched: mark should_resched() __always_inline Andi Kleen
2013-08-09 23:04 ` [PATCH 06/13] x86: Add 32bit versions of SAVE_ALL/RESTORE_ALL to calling.h Andi Kleen
2013-08-09 23:04 ` [PATCH 07/13] Add might_fault_debug_only() Andi Kleen
2013-08-14 18:24 ` Michael S. Tsirkin
2013-08-09 23:04 ` Andi Kleen [this message]
2013-08-09 23:04 ` [PATCH 09/13] x86: Move cond_resched into the out of line get_user code Andi Kleen
2013-08-09 23:04 ` [PATCH 10/13] x86: Move cond resched for copy_{from,to}_user into low level code 64bit Andi Kleen
2013-08-10 15:42 ` Linus Torvalds
2013-08-10 16:10 ` Andi Kleen
2013-08-10 16:27 ` Linus Torvalds
2013-08-10 18:23 ` Borislav Petkov
2013-08-10 19:05 ` Jörn Engel
2013-08-20 21:03 ` KOSAKI Motohiro
2013-08-15 5:04 ` Michael S. Tsirkin
2013-08-09 23:04 ` [PATCH 11/13] sched: Inline the need_resched test into the caller for _cond_resched Andi Kleen
2013-08-09 23:04 ` [PATCH 12/13] x86: move __copy_*_nocache might fault check out of line Andi Kleen
2013-08-09 23:04 ` [PATCH 13/13] x86: drop cond rescheds from __copy_{from,to}_user Andi Kleen
2013-08-10 4:42 ` Re-tune x86 uaccess code for PREEMPT_VOLUNTARY H. Peter Anvin
2013-08-10 5:55 ` Mike Galbraith
2013-08-10 16:09 ` H. Peter Anvin
2013-08-10 16:43 ` Linus Torvalds
2013-08-10 17:18 ` H. Peter Anvin
2013-08-10 18:51 ` Linus Torvalds
2013-08-10 19:18 ` H. Peter Anvin
2013-08-10 20:26 ` H. Peter Anvin
2013-08-10 23:00 ` H. Peter Anvin
2013-08-11 4:17 ` Mike Galbraith
2013-08-11 4:27 ` H. Peter Anvin
2013-08-11 4:36 ` Mike Galbraith
2013-08-11 4:57 ` H. Peter Anvin
2013-08-11 5:58 ` Mike Galbraith
2013-08-13 18:09 ` H. Peter Anvin
2013-08-13 18:12 ` Andi Kleen
2013-08-14 18:27 ` Michael S. Tsirkin
2013-08-14 22:08 ` Andi Kleen
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