Re: [PATCH 1 of 4] mm: add a ptep_modify_prot transaction abstraction

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To: Linus Torvalds <torvalds@...>
Cc: Jeremy Fitzhardinge <jeremy@...>, <benh@...>, xen-devel <xen-devel@...>, Peter Zijlstra <a.p.zijlstra@...>, kvm-devel <kvm-devel@...>, <x86@...>, LKML <linux-kernel@...>, Virtualization Mailing List <virtualization@...>, Hugh Dickins <hugh@...>, Thomas Gleixner <tglx@...>
Date: Friday, June 20, 2008 - 6:10 am

* Ingo Molnar <mingo@elte.hu> wrote:


yep, the patch below got it all going and it passed 5 hours of testing 
already. Thanks,

	Ingo

------------------->
commit 7dbceaf9bb68919651901b101f44edd5391ee489
Author: Ingo Molnar <mingo@elte.hu>
Date:   Fri Jun 20 07:28:24 2008 +0200

    x86, bitops: make constant-bit set/clear_bit ops faster, adapt, clean up
    
    fix integration bug introduced by "x86: bitops take an unsigned long *"
    which turned "(void *) + x" into "(long *) + x".
    
    small cleanups to make it more apparent which value get propagated where.
    
    Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/include/asm-x86/bitops.h b/include/asm-x86/bitops.h
index ab7635a..6c50548 100644
--- a/include/asm-x86/bitops.h
+++ b/include/asm-x86/bitops.h
@@ -28,16 +28,15 @@
 #define BITOP_ADDR(x) "+m" (*(volatile long *) (x))
 #endif
 
-#define ADDR BITOP_ADDR(addr)
+#define ADDR				BITOP_ADDR(addr)
 
 /*
  * We do the locked ops that don't return the old value as
  * a mask operation on a byte.
  */
-#define IS_IMMEDIATE(nr) \
-	(__builtin_constant_p(nr))
-#define CONST_MASK_ADDR BITOP_ADDR(addr + (nr>>3))
-#define CONST_MASK (1 << (nr & 7))
+#define IS_IMMEDIATE(nr)		(__builtin_constant_p(nr))
+#define CONST_MASK_ADDR(nr, addr)	BITOP_ADDR((void *)(addr) + ((nr)>>3))
+#define CONST_MASK(nr)			(1 << ((nr) & 7))
 
 /**
  * set_bit - Atomically set a bit in memory
@@ -56,13 +55,17 @@
  */
 static inline void set_bit(unsigned int nr, volatile unsigned long *addr)
 {
-	if (IS_IMMEDIATE(nr))
-		asm volatile(LOCK_PREFIX "orb %1,%0" : CONST_MASK_ADDR : "i" (CONST_MASK) : "memory");
-	else
-		asm volatile(LOCK_PREFIX "bts %1,%0" : ADDR : "Ir" (nr) : "memory");
+	if (IS_IMMEDIATE(nr)) {
+		asm volatile(LOCK_PREFIX "orb %1,%0"
+			: CONST_MASK_ADDR(nr, addr)
+			: "i" (CONST_MASK(nr))
+			: "memory");
+	} else {
+		asm volatile(LOCK_PREFIX "bts %1,%0"
+			: BITOP_ADDR(addr) : "Ir" (nr) : "memory");
+	}
 }
 
-
 /**
  * __set_bit - Set a bit in memory
  * @nr: the bit to set
@@ -89,10 +92,15 @@ static inline void __set_bit(int nr, volatile unsigned long *addr)
  */
 static inline void clear_bit(int nr, volatile unsigned long *addr)
 {
-	if (IS_IMMEDIATE(nr))
-		asm volatile(LOCK_PREFIX "andb %1,%0" : CONST_MASK_ADDR : "i" (~CONST_MASK));
-	else
-		asm volatile(LOCK_PREFIX "btr %1,%0" : ADDR : "Ir" (nr));
+	if (IS_IMMEDIATE(nr)) {
+		asm volatile(LOCK_PREFIX "andb %1,%0"
+			: CONST_MASK_ADDR(nr, addr)
+			: "i" (~CONST_MASK(nr)));
+	} else {
+		asm volatile(LOCK_PREFIX "btr %1,%0"
+			: BITOP_ADDR(addr)
+			: "Ir" (nr));
+	}
 }
 
 /*
--
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Messages in current thread:
[PATCH 0 of 4] mm+paravirt+xen: add pte read-modify-write ab..., Jeremy Fitzhardinge, (Mon Jun 16, 7:29 am)
[PATCH 2 of 4] paravirt: add hooks for ptep_modify_prot_star..., Jeremy Fitzhardinge, (Mon Jun 16, 7:30 am)
[PATCH 4 of 4] xen: add mechanism to extend existing multica..., Jeremy Fitzhardinge, (Mon Jun 16, 7:30 am)
[PATCH 3 of 4] xen: implement ptep_modify_prot_start/commit, Jeremy Fitzhardinge, (Mon Jun 16, 7:30 am)
[PATCH 1 of 4] mm: add a ptep_modify_prot transaction abstra..., Jeremy Fitzhardinge, (Mon Jun 16, 7:30 am)
Re: [PATCH 1 of 4] mm: add a ptep_modify_prot transaction ab..., Benjamin Herrenschmidt, (Wed Jun 18, 7:23 pm)
Re: [PATCH 1 of 4] mm: add a ptep_modify_prot transaction ab..., Jeremy Fitzhardinge, (Wed Jun 18, 7:59 pm)
Re: [PATCH 1 of 4] mm: add a ptep_modify_prot transaction ab..., Jeremy Fitzhardinge, (Wed Jun 18, 8:15 pm)
Re: [PATCH 1 of 4] mm: add a ptep_modify_prot transaction ab..., Benjamin Herrenschmidt, (Wed Jun 18, 8:39 pm)
Re: [PATCH 1 of 4] mm: add a ptep_modify_prot transaction ab..., Jeremy Fitzhardinge, (Thu Jun 19, 1:03 am)
Re: [PATCH 1 of 4] mm: add a ptep_modify_prot transaction ab..., Benjamin Herrenschmidt, (Thu Jun 19, 3:20 am)
Re: [PATCH 1 of 4] mm: add a ptep_modify_prot transaction ab..., Jeremy Fitzhardinge, (Thu Jun 19, 1:57 pm)
Re: [PATCH 1 of 4] mm: add a ptep_modify_prot transaction ab..., Jeremy Fitzhardinge, (Wed Jun 18, 8:37 pm)
Re: [PATCH 1 of 4] mm: add a ptep_modify_prot transaction ab..., Ingo Molnar, (Fri Jun 20, 6:10 am)
Re: [PATCH 1 of 4] mm: add a ptep_modify_prot transaction ab..., Jeremy Fitzhardinge, (Fri Jun 20, 3:06 pm)
Re: [PATCH 1 of 4] mm: add a ptep_modify_prot transaction ab..., Jeremy Fitzhardinge, (Fri Jun 20, 4:05 pm)
Re: [PATCH 1 of 4] mm: add a ptep_modify_prot transaction ab..., Jeremy Fitzhardinge, (Fri Jun 20, 4:16 pm)
Re: [PATCH 1 of 4] mm: add a ptep_modify_prot transaction ab..., Jeremy Fitzhardinge, (Fri Jun 20, 4:22 pm)