From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ingo Molnar Subject: Re: [PATCH 1 of 4] mm: add a ptep_modify_prot transaction abstraction Date: Fri, 20 Jun 2008 12:10:28 +0200 Message-ID: <20080620101028.GA23664@elte.hu> References: <1213831403.8011.24.camel@pasglop> <4859A149.9090004@goop.org> <4859A528.1010107@goop.org> <4859AA47.2020903@goop.org> <20080619115832.GM15228@elte.hu> <20080619164708.GA32190@elte.hu> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20080619164708.GA32190@elte.hu> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Linus Torvalds Cc: Jeremy Fitzhardinge , xen-devel , Peter Zijlstra , kvm-devel , benh@kernel.crashing.org, x86@kernel.org, LKML , Virtualization Mailing List , Hugh Dickins , Thomas Gleixner List-Id: virtualization@lists.linuxfoundation.org * Ingo Molnar wrote: > > * Linus Torvalds wrote: > > > On Thu, 19 Jun 2008, Ingo Molnar wrote: > > > > > > Below is the commit, it needed a small amount of massaging to apply the > > > void * -> unsigned long * change in the x86/bitops topic. > > > > Well, that's your bug right there. > > > > The macros very much depended on the pointers being "void *", due to > > the pointer arithmetic (which is a gcc extension that we use > > extensively - "void *" arithmetic works as if it was a byte > > pointer). > > duh, yeah - of course. Will retry with that fixed :) yep, the patch below got it all going and it passed 5 hours of testing already. Thanks, Ingo -------------------> commit 7dbceaf9bb68919651901b101f44edd5391ee489 Author: Ingo Molnar 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 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)); + } } /*