From: Christoph Lameter <cl@linux-foundation.org>
To: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Tejun Heo <tj@kernel.org>
Cc: linux-kernel@vger.kernel.org
Subject: [RFC local_t removal V1 4/4] Remove local_t support
Date: Tue, 05 Jan 2010 16:04:21 -0600 [thread overview]
Message-ID: <20100105220439.566620901@quilx.com> (raw)
In-Reply-To: 20100105220417.400092933@quilx.com
[-- Attachment #1: remove_local_t_actual_remove --]
[-- Type: text/plain, Size: 46853 bytes --]
No user of local_t remains.
Signed-off-by: Christoph Lameter <cl@linux-foundation.org>
---
Documentation/DocBook/kernel-locking.tmpl | 8
Documentation/atomic_ops.txt | 7
Documentation/local_ops.txt | 186 ----------------
arch/alpha/include/asm/local.h | 101 --------
arch/arm/include/asm/local.h | 1
arch/avr32/include/asm/local.h | 6
arch/blackfin/include/asm/local.h | 1
arch/cris/include/asm/local.h | 1
arch/frv/include/asm/local.h | 6
arch/frv/kernel/local.h | 59 -----
arch/h8300/include/asm/local.h | 6
arch/ia64/include/asm/local.h | 1
arch/m32r/include/asm/local.h | 341 ------------------------------
arch/m68k/include/asm/local.h | 6
arch/microblaze/include/asm/local.h | 1
arch/mips/include/asm/local.h | 196 -----------------
arch/mn10300/include/asm/local.h | 1
arch/parisc/include/asm/local.h | 1
arch/powerpc/include/asm/local.h | 175 ---------------
arch/s390/include/asm/local.h | 1
arch/score/include/asm/local.h | 6
arch/sh/include/asm/local.h | 7
arch/sparc/include/asm/local.h | 6
arch/x86/include/asm/local.h | 198 -----------------
arch/xtensa/include/asm/local.h | 16 -
include/asm-generic/local.h | 55 ----
26 files changed, 4 insertions(+), 1389 deletions(-)
Index: linux-2.6/arch/frv/kernel/local.h
===================================================================
--- linux-2.6.orig/arch/frv/kernel/local.h 2009-11-13 09:33:01.000000000 -0600
+++ /dev/null 1970-01-01 00:00:00.000000000 +0000
@@ -1,59 +0,0 @@
-/* local.h: local definitions
- *
- * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
- * Written by David Howells (dhowells@redhat.com)
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License
- * as published by the Free Software Foundation; either version
- * 2 of the License, or (at your option) any later version.
- */
-
-#ifndef _FRV_LOCAL_H
-#define _FRV_LOCAL_H
-
-#include <asm/sections.h>
-
-#ifndef __ASSEMBLY__
-
-/* dma.c */
-extern unsigned long frv_dma_inprogress;
-
-extern void frv_dma_pause_all(void);
-extern void frv_dma_resume_all(void);
-
-/* sleep.S */
-extern asmlinkage void frv_cpu_suspend(unsigned long);
-extern asmlinkage void frv_cpu_core_sleep(void);
-
-/* setup.c */
-extern unsigned long __nongprelbss pdm_suspend_mode;
-extern void determine_clocks(int verbose);
-extern int __nongprelbss clock_p0_current;
-extern int __nongprelbss clock_cm_current;
-extern int __nongprelbss clock_cmode_current;
-
-#ifdef CONFIG_PM
-extern int __nongprelbss clock_cmodes_permitted;
-extern unsigned long __nongprelbss clock_bits_settable;
-#define CLOCK_BIT_CM 0x0000000f
-#define CLOCK_BIT_CM_H 0x00000001 /* CLKC.CM can be set to 0 */
-#define CLOCK_BIT_CM_M 0x00000002 /* CLKC.CM can be set to 1 */
-#define CLOCK_BIT_CM_L 0x00000004 /* CLKC.CM can be set to 2 */
-#define CLOCK_BIT_P0 0x00000010 /* CLKC.P0 can be changed */
-#define CLOCK_BIT_CMODE 0x00000020 /* CLKC.CMODE can be changed */
-
-extern void (*__power_switch_wake_setup)(void);
-extern int (*__power_switch_wake_check)(void);
-extern void (*__power_switch_wake_cleanup)(void);
-#endif
-
-/* time.c */
-extern void time_divisor_init(void);
-
-/* cmode.S */
-extern asmlinkage void frv_change_cmode(int);
-
-
-#endif /* __ASSEMBLY__ */
-#endif /* _FRV_LOCAL_H */
Index: linux-2.6/arch/alpha/include/asm/local.h
===================================================================
--- linux-2.6.orig/arch/alpha/include/asm/local.h 2010-01-05 15:35:34.000000000 -0600
+++ /dev/null 1970-01-01 00:00:00.000000000 +0000
@@ -1,101 +0,0 @@
-#ifndef _ALPHA_LOCAL_H
-#define _ALPHA_LOCAL_H
-
-#include <linux/percpu.h>
-#include <asm/atomic.h>
-
-typedef struct
-{
- atomic_long_t a;
-} local_t;
-
-#define LOCAL_INIT(i) { ATOMIC_LONG_INIT(i) }
-#define local_read(l) atomic_long_read(&(l)->a)
-#define local_set(l,i) atomic_long_set(&(l)->a, (i))
-#define local_inc(l) atomic_long_inc(&(l)->a)
-#define local_dec(l) atomic_long_dec(&(l)->a)
-#define local_add(i,l) atomic_long_add((i),(&(l)->a))
-#define local_sub(i,l) atomic_long_sub((i),(&(l)->a))
-
-static __inline__ long local_add_return(long i, local_t * l)
-{
- long temp, result;
- __asm__ __volatile__(
- "1: ldq_l %0,%1\n"
- " addq %0,%3,%2\n"
- " addq %0,%3,%0\n"
- " stq_c %0,%1\n"
- " beq %0,2f\n"
- ".subsection 2\n"
- "2: br 1b\n"
- ".previous"
- :"=&r" (temp), "=m" (l->a.counter), "=&r" (result)
- :"Ir" (i), "m" (l->a.counter) : "memory");
- return result;
-}
-
-static __inline__ long local_sub_return(long i, local_t * l)
-{
- long temp, result;
- __asm__ __volatile__(
- "1: ldq_l %0,%1\n"
- " subq %0,%3,%2\n"
- " subq %0,%3,%0\n"
- " stq_c %0,%1\n"
- " beq %0,2f\n"
- ".subsection 2\n"
- "2: br 1b\n"
- ".previous"
- :"=&r" (temp), "=m" (l->a.counter), "=&r" (result)
- :"Ir" (i), "m" (l->a.counter) : "memory");
- return result;
-}
-
-#define local_cmpxchg(l, o, n) \
- (cmpxchg_local(&((l)->a.counter), (o), (n)))
-#define local_xchg(l, n) (xchg_local(&((l)->a.counter), (n)))
-
-/**
- * local_add_unless - add unless the number is a given value
- * @l: pointer of type local_t
- * @a: the amount to add to l...
- * @u: ...unless l is equal to u.
- *
- * Atomically adds @a to @l, so long as it was not @u.
- * Returns non-zero if @l was not @u, and zero otherwise.
- */
-#define local_add_unless(l, a, u) \
-({ \
- long c, old; \
- c = local_read(l); \
- for (;;) { \
- if (unlikely(c == (u))) \
- break; \
- old = local_cmpxchg((l), c, c + (a)); \
- if (likely(old == c)) \
- break; \
- c = old; \
- } \
- c != (u); \
-})
-#define local_inc_not_zero(l) local_add_unless((l), 1, 0)
-
-#define local_add_negative(a, l) (local_add_return((a), (l)) < 0)
-
-#define local_dec_return(l) local_sub_return(1,(l))
-
-#define local_inc_return(l) local_add_return(1,(l))
-
-#define local_sub_and_test(i,l) (local_sub_return((i), (l)) == 0)
-
-#define local_inc_and_test(l) (local_add_return(1, (l)) == 0)
-
-#define local_dec_and_test(l) (local_sub_return(1, (l)) == 0)
-
-/* Verify if faster than atomic ops */
-#define __local_inc(l) ((l)->a.counter++)
-#define __local_dec(l) ((l)->a.counter++)
-#define __local_add(i,l) ((l)->a.counter+=(i))
-#define __local_sub(i,l) ((l)->a.counter-=(i))
-
-#endif /* _ALPHA_LOCAL_H */
Index: linux-2.6/arch/arm/include/asm/local.h
===================================================================
--- linux-2.6.orig/arch/arm/include/asm/local.h 2009-11-13 09:32:55.000000000 -0600
+++ /dev/null 1970-01-01 00:00:00.000000000 +0000
@@ -1 +0,0 @@
-#include <asm-generic/local.h>
Index: linux-2.6/arch/avr32/include/asm/local.h
===================================================================
--- linux-2.6.orig/arch/avr32/include/asm/local.h 2009-11-13 09:32:59.000000000 -0600
+++ /dev/null 1970-01-01 00:00:00.000000000 +0000
@@ -1,6 +0,0 @@
-#ifndef __ASM_AVR32_LOCAL_H
-#define __ASM_AVR32_LOCAL_H
-
-#include <asm-generic/local.h>
-
-#endif /* __ASM_AVR32_LOCAL_H */
Index: linux-2.6/arch/blackfin/include/asm/local.h
===================================================================
--- linux-2.6.orig/arch/blackfin/include/asm/local.h 2009-11-13 09:32:59.000000000 -0600
+++ /dev/null 1970-01-01 00:00:00.000000000 +0000
@@ -1 +0,0 @@
-#include <asm-generic/local.h>
Index: linux-2.6/arch/cris/include/asm/local.h
===================================================================
--- linux-2.6.orig/arch/cris/include/asm/local.h 2009-11-13 09:33:01.000000000 -0600
+++ /dev/null 1970-01-01 00:00:00.000000000 +0000
@@ -1 +0,0 @@
-#include <asm-generic/local.h>
Index: linux-2.6/arch/frv/include/asm/local.h
===================================================================
--- linux-2.6.orig/arch/frv/include/asm/local.h 2009-11-13 09:33:01.000000000 -0600
+++ /dev/null 1970-01-01 00:00:00.000000000 +0000
@@ -1,6 +0,0 @@
-#ifndef _ASM_LOCAL_H
-#define _ASM_LOCAL_H
-
-#include <asm-generic/local.h>
-
-#endif /* _ASM_LOCAL_H */
Index: linux-2.6/arch/h8300/include/asm/local.h
===================================================================
--- linux-2.6.orig/arch/h8300/include/asm/local.h 2009-11-13 09:33:01.000000000 -0600
+++ /dev/null 1970-01-01 00:00:00.000000000 +0000
@@ -1,6 +0,0 @@
-#ifndef _H8300_LOCAL_H_
-#define _H8300_LOCAL_H_
-
-#include <asm-generic/local.h>
-
-#endif
Index: linux-2.6/arch/ia64/include/asm/local.h
===================================================================
--- linux-2.6.orig/arch/ia64/include/asm/local.h 2009-11-13 09:33:01.000000000 -0600
+++ /dev/null 1970-01-01 00:00:00.000000000 +0000
@@ -1 +0,0 @@
-#include <asm-generic/local.h>
Index: linux-2.6/arch/m32r/include/asm/local.h
===================================================================
--- linux-2.6.orig/arch/m32r/include/asm/local.h 2010-01-05 15:35:34.000000000 -0600
+++ /dev/null 1970-01-01 00:00:00.000000000 +0000
@@ -1,341 +0,0 @@
-#ifndef __M32R_LOCAL_H
-#define __M32R_LOCAL_H
-
-/*
- * linux/include/asm-m32r/local.h
- *
- * M32R version:
- * Copyright (C) 2001, 2002 Hitoshi Yamamoto
- * Copyright (C) 2004 Hirokazu Takata <takata at linux-m32r.org>
- * Copyright (C) 2007 Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
- */
-
-#include <linux/percpu.h>
-#include <asm/assembler.h>
-#include <asm/system.h>
-#include <asm/local.h>
-
-/*
- * Atomic operations that C can't guarantee us. Useful for
- * resource counting etc..
- */
-
-/*
- * Make sure gcc doesn't try to be clever and move things around
- * on us. We need to use _exactly_ the address the user gave us,
- * not some alias that contains the same information.
- */
-typedef struct { volatile int counter; } local_t;
-
-#define LOCAL_INIT(i) { (i) }
-
-/**
- * local_read - read local variable
- * @l: pointer of type local_t
- *
- * Atomically reads the value of @l.
- */
-#define local_read(l) ((l)->counter)
-
-/**
- * local_set - set local variable
- * @l: pointer of type local_t
- * @i: required value
- *
- * Atomically sets the value of @l to @i.
- */
-#define local_set(l, i) (((l)->counter) = (i))
-
-/**
- * local_add_return - add long to local variable and return it
- * @i: long value to add
- * @l: pointer of type local_t
- *
- * Atomically adds @i to @l and return (@i + @l).
- */
-static inline long local_add_return(long i, local_t *l)
-{
- unsigned long flags;
- long result;
-
- local_irq_save(flags);
- __asm__ __volatile__ (
- "# local_add_return \n\t"
- DCACHE_CLEAR("%0", "r4", "%1")
- "ld %0, @%1; \n\t"
- "add %0, %2; \n\t"
- "st %0, @%1; \n\t"
- : "=&r" (result)
- : "r" (&l->counter), "r" (i)
- : "memory"
-#ifdef CONFIG_CHIP_M32700_TS1
- , "r4"
-#endif /* CONFIG_CHIP_M32700_TS1 */
- );
- local_irq_restore(flags);
-
- return result;
-}
-
-/**
- * local_sub_return - subtract long from local variable and return it
- * @i: long value to subtract
- * @l: pointer of type local_t
- *
- * Atomically subtracts @i from @l and return (@l - @i).
- */
-static inline long local_sub_return(long i, local_t *l)
-{
- unsigned long flags;
- long result;
-
- local_irq_save(flags);
- __asm__ __volatile__ (
- "# local_sub_return \n\t"
- DCACHE_CLEAR("%0", "r4", "%1")
- "ld %0, @%1; \n\t"
- "sub %0, %2; \n\t"
- "st %0, @%1; \n\t"
- : "=&r" (result)
- : "r" (&l->counter), "r" (i)
- : "memory"
-#ifdef CONFIG_CHIP_M32700_TS1
- , "r4"
-#endif /* CONFIG_CHIP_M32700_TS1 */
- );
- local_irq_restore(flags);
-
- return result;
-}
-
-/**
- * local_add - add long to local variable
- * @i: long value to add
- * @l: pointer of type local_t
- *
- * Atomically adds @i to @l.
- */
-#define local_add(i, l) ((void) local_add_return((i), (l)))
-
-/**
- * local_sub - subtract the local variable
- * @i: long value to subtract
- * @l: pointer of type local_t
- *
- * Atomically subtracts @i from @l.
- */
-#define local_sub(i, l) ((void) local_sub_return((i), (l)))
-
-/**
- * local_sub_and_test - subtract value from variable and test result
- * @i: integer value to subtract
- * @l: pointer of type local_t
- *
- * Atomically subtracts @i from @l and returns
- * true if the result is zero, or false for all
- * other cases.
- */
-#define local_sub_and_test(i, l) (local_sub_return((i), (l)) == 0)
-
-/**
- * local_inc_return - increment local variable and return it
- * @l: pointer of type local_t
- *
- * Atomically increments @l by 1 and returns the result.
- */
-static inline long local_inc_return(local_t *l)
-{
- unsigned long flags;
- long result;
-
- local_irq_save(flags);
- __asm__ __volatile__ (
- "# local_inc_return \n\t"
- DCACHE_CLEAR("%0", "r4", "%1")
- "ld %0, @%1; \n\t"
- "addi %0, #1; \n\t"
- "st %0, @%1; \n\t"
- : "=&r" (result)
- : "r" (&l->counter)
- : "memory"
-#ifdef CONFIG_CHIP_M32700_TS1
- , "r4"
-#endif /* CONFIG_CHIP_M32700_TS1 */
- );
- local_irq_restore(flags);
-
- return result;
-}
-
-/**
- * local_dec_return - decrement local variable and return it
- * @l: pointer of type local_t
- *
- * Atomically decrements @l by 1 and returns the result.
- */
-static inline long local_dec_return(local_t *l)
-{
- unsigned long flags;
- long result;
-
- local_irq_save(flags);
- __asm__ __volatile__ (
- "# local_dec_return \n\t"
- DCACHE_CLEAR("%0", "r4", "%1")
- "ld %0, @%1; \n\t"
- "addi %0, #-1; \n\t"
- "st %0, @%1; \n\t"
- : "=&r" (result)
- : "r" (&l->counter)
- : "memory"
-#ifdef CONFIG_CHIP_M32700_TS1
- , "r4"
-#endif /* CONFIG_CHIP_M32700_TS1 */
- );
- local_irq_restore(flags);
-
- return result;
-}
-
-/**
- * local_inc - increment local variable
- * @l: pointer of type local_t
- *
- * Atomically increments @l by 1.
- */
-#define local_inc(l) ((void)local_inc_return(l))
-
-/**
- * local_dec - decrement local variable
- * @l: pointer of type local_t
- *
- * Atomically decrements @l by 1.
- */
-#define local_dec(l) ((void)local_dec_return(l))
-
-/**
- * local_inc_and_test - increment and test
- * @l: pointer of type local_t
- *
- * Atomically increments @l by 1
- * and returns true if the result is zero, or false for all
- * other cases.
- */
-#define local_inc_and_test(l) (local_inc_return(l) == 0)
-
-/**
- * local_dec_and_test - decrement and test
- * @l: pointer of type local_t
- *
- * Atomically decrements @l by 1 and
- * returns true if the result is 0, or false for all
- * other cases.
- */
-#define local_dec_and_test(l) (local_dec_return(l) == 0)
-
-/**
- * local_add_negative - add and test if negative
- * @l: pointer of type local_t
- * @i: integer value to add
- *
- * Atomically adds @i to @l and returns true
- * if the result is negative, or false when
- * result is greater than or equal to zero.
- */
-#define local_add_negative(i, l) (local_add_return((i), (l)) < 0)
-
-#define local_cmpxchg(l, o, n) (cmpxchg_local(&((l)->counter), (o), (n)))
-#define local_xchg(v, new) (xchg_local(&((l)->counter), new))
-
-/**
- * local_add_unless - add unless the number is a given value
- * @l: pointer of type local_t
- * @a: the amount to add to l...
- * @u: ...unless l is equal to u.
- *
- * Atomically adds @a to @l, so long as it was not @u.
- * Returns non-zero if @l was not @u, and zero otherwise.
- */
-static inline int local_add_unless(local_t *l, long a, long u)
-{
- long c, old;
- c = local_read(l);
- for (;;) {
- if (unlikely(c == (u)))
- break;
- old = local_cmpxchg((l), c, c + (a));
- if (likely(old == c))
- break;
- c = old;
- }
- return c != (u);
-}
-
-#define local_inc_not_zero(l) local_add_unless((l), 1, 0)
-
-static inline void local_clear_mask(unsigned long mask, local_t *addr)
-{
- unsigned long flags;
- unsigned long tmp;
-
- local_irq_save(flags);
- __asm__ __volatile__ (
- "# local_clear_mask \n\t"
- DCACHE_CLEAR("%0", "r5", "%1")
- "ld %0, @%1; \n\t"
- "and %0, %2; \n\t"
- "st %0, @%1; \n\t"
- : "=&r" (tmp)
- : "r" (addr), "r" (~mask)
- : "memory"
-#ifdef CONFIG_CHIP_M32700_TS1
- , "r5"
-#endif /* CONFIG_CHIP_M32700_TS1 */
- );
- local_irq_restore(flags);
-}
-
-static inline void local_set_mask(unsigned long mask, local_t *addr)
-{
- unsigned long flags;
- unsigned long tmp;
-
- local_irq_save(flags);
- __asm__ __volatile__ (
- "# local_set_mask \n\t"
- DCACHE_CLEAR("%0", "r5", "%1")
- "ld %0, @%1; \n\t"
- "or %0, %2; \n\t"
- "st %0, @%1; \n\t"
- : "=&r" (tmp)
- : "r" (addr), "r" (mask)
- : "memory"
-#ifdef CONFIG_CHIP_M32700_TS1
- , "r5"
-#endif /* CONFIG_CHIP_M32700_TS1 */
- );
- local_irq_restore(flags);
-}
-
-/* Atomic operations are already serializing on m32r */
-#define smp_mb__before_local_dec() barrier()
-#define smp_mb__after_local_dec() barrier()
-#define smp_mb__before_local_inc() barrier()
-#define smp_mb__after_local_inc() barrier()
-
-/* Use these for per-cpu local_t variables: on some archs they are
- * much more efficient than these naive implementations. Note they take
- * a variable, not an address.
- */
-
-#define __local_inc(l) ((l)->a.counter++)
-#define __local_dec(l) ((l)->a.counter++)
-#define __local_add(i, l) ((l)->a.counter += (i))
-#define __local_sub(i, l) ((l)->a.counter -= (i))
-
-/* Use these for per-cpu local_t variables: on some archs they are
- * much more efficient than these naive implementations. Note they take
- * a variable, not an address.
- */
-
-#endif /* __M32R_LOCAL_H */
Index: linux-2.6/arch/m68k/include/asm/local.h
===================================================================
--- linux-2.6.orig/arch/m68k/include/asm/local.h 2009-11-13 09:33:02.000000000 -0600
+++ /dev/null 1970-01-01 00:00:00.000000000 +0000
@@ -1,6 +0,0 @@
-#ifndef _ASM_M68K_LOCAL_H
-#define _ASM_M68K_LOCAL_H
-
-#include <asm-generic/local.h>
-
-#endif /* _ASM_M68K_LOCAL_H */
Index: linux-2.6/arch/microblaze/include/asm/local.h
===================================================================
--- linux-2.6.orig/arch/microblaze/include/asm/local.h 2009-11-13 09:33:03.000000000 -0600
+++ /dev/null 1970-01-01 00:00:00.000000000 +0000
@@ -1 +0,0 @@
-#include <asm-generic/local.h>
Index: linux-2.6/arch/mips/include/asm/local.h
===================================================================
--- linux-2.6.orig/arch/mips/include/asm/local.h 2010-01-05 15:35:34.000000000 -0600
+++ /dev/null 1970-01-01 00:00:00.000000000 +0000
@@ -1,196 +0,0 @@
-#ifndef _ARCH_MIPS_LOCAL_H
-#define _ARCH_MIPS_LOCAL_H
-
-#include <linux/percpu.h>
-#include <linux/bitops.h>
-#include <asm/atomic.h>
-#include <asm/cmpxchg.h>
-#include <asm/war.h>
-
-typedef struct
-{
- atomic_long_t a;
-} local_t;
-
-#define LOCAL_INIT(i) { ATOMIC_LONG_INIT(i) }
-
-#define local_read(l) atomic_long_read(&(l)->a)
-#define local_set(l, i) atomic_long_set(&(l)->a, (i))
-
-#define local_add(i, l) atomic_long_add((i), (&(l)->a))
-#define local_sub(i, l) atomic_long_sub((i), (&(l)->a))
-#define local_inc(l) atomic_long_inc(&(l)->a)
-#define local_dec(l) atomic_long_dec(&(l)->a)
-
-/*
- * Same as above, but return the result value
- */
-static __inline__ long local_add_return(long i, local_t * l)
-{
- unsigned long result;
-
- if (kernel_uses_llsc && R10000_LLSC_WAR) {
- unsigned long temp;
-
- __asm__ __volatile__(
- " .set mips3 \n"
- "1:" __LL "%1, %2 # local_add_return \n"
- " addu %0, %1, %3 \n"
- __SC "%0, %2 \n"
- " beqzl %0, 1b \n"
- " addu %0, %1, %3 \n"
- " .set mips0 \n"
- : "=&r" (result), "=&r" (temp), "=m" (l->a.counter)
- : "Ir" (i), "m" (l->a.counter)
- : "memory");
- } else if (kernel_uses_llsc) {
- unsigned long temp;
-
- __asm__ __volatile__(
- " .set mips3 \n"
- "1:" __LL "%1, %2 # local_add_return \n"
- " addu %0, %1, %3 \n"
- __SC "%0, %2 \n"
- " beqz %0, 1b \n"
- " addu %0, %1, %3 \n"
- " .set mips0 \n"
- : "=&r" (result), "=&r" (temp), "=m" (l->a.counter)
- : "Ir" (i), "m" (l->a.counter)
- : "memory");
- } else {
- unsigned long flags;
-
- local_irq_save(flags);
- result = l->a.counter;
- result += i;
- l->a.counter = result;
- local_irq_restore(flags);
- }
-
- return result;
-}
-
-static __inline__ long local_sub_return(long i, local_t * l)
-{
- unsigned long result;
-
- if (kernel_uses_llsc && R10000_LLSC_WAR) {
- unsigned long temp;
-
- __asm__ __volatile__(
- " .set mips3 \n"
- "1:" __LL "%1, %2 # local_sub_return \n"
- " subu %0, %1, %3 \n"
- __SC "%0, %2 \n"
- " beqzl %0, 1b \n"
- " subu %0, %1, %3 \n"
- " .set mips0 \n"
- : "=&r" (result), "=&r" (temp), "=m" (l->a.counter)
- : "Ir" (i), "m" (l->a.counter)
- : "memory");
- } else if (kernel_uses_llsc) {
- unsigned long temp;
-
- __asm__ __volatile__(
- " .set mips3 \n"
- "1:" __LL "%1, %2 # local_sub_return \n"
- " subu %0, %1, %3 \n"
- __SC "%0, %2 \n"
- " beqz %0, 1b \n"
- " subu %0, %1, %3 \n"
- " .set mips0 \n"
- : "=&r" (result), "=&r" (temp), "=m" (l->a.counter)
- : "Ir" (i), "m" (l->a.counter)
- : "memory");
- } else {
- unsigned long flags;
-
- local_irq_save(flags);
- result = l->a.counter;
- result -= i;
- l->a.counter = result;
- local_irq_restore(flags);
- }
-
- return result;
-}
-
-#define local_cmpxchg(l, o, n) \
- ((long)cmpxchg_local(&((l)->a.counter), (o), (n)))
-#define local_xchg(l, n) (xchg_local(&((l)->a.counter), (n)))
-
-/**
- * local_add_unless - add unless the number is a given value
- * @l: pointer of type local_t
- * @a: the amount to add to l...
- * @u: ...unless l is equal to u.
- *
- * Atomically adds @a to @l, so long as it was not @u.
- * Returns non-zero if @l was not @u, and zero otherwise.
- */
-#define local_add_unless(l, a, u) \
-({ \
- long c, old; \
- c = local_read(l); \
- while (c != (u) && (old = local_cmpxchg((l), c, c + (a))) != c) \
- c = old; \
- c != (u); \
-})
-#define local_inc_not_zero(l) local_add_unless((l), 1, 0)
-
-#define local_dec_return(l) local_sub_return(1, (l))
-#define local_inc_return(l) local_add_return(1, (l))
-
-/*
- * local_sub_and_test - subtract value from variable and test result
- * @i: integer value to subtract
- * @l: pointer of type local_t
- *
- * Atomically subtracts @i from @l and returns
- * true if the result is zero, or false for all
- * other cases.
- */
-#define local_sub_and_test(i, l) (local_sub_return((i), (l)) == 0)
-
-/*
- * local_inc_and_test - increment and test
- * @l: pointer of type local_t
- *
- * Atomically increments @l by 1
- * and returns true if the result is zero, or false for all
- * other cases.
- */
-#define local_inc_and_test(l) (local_inc_return(l) == 0)
-
-/*
- * local_dec_and_test - decrement by 1 and test
- * @l: pointer of type local_t
- *
- * Atomically decrements @l by 1 and
- * returns true if the result is 0, or false for all other
- * cases.
- */
-#define local_dec_and_test(l) (local_sub_return(1, (l)) == 0)
-
-/*
- * local_add_negative - add and test if negative
- * @l: pointer of type local_t
- * @i: integer value to add
- *
- * Atomically adds @i to @l and returns true
- * if the result is negative, or false when
- * result is greater than or equal to zero.
- */
-#define local_add_negative(i, l) (local_add_return(i, (l)) < 0)
-
-/* Use these for per-cpu local_t variables: on some archs they are
- * much more efficient than these naive implementations. Note they take
- * a variable, not an address.
- */
-
-#define __local_inc(l) ((l)->a.counter++)
-#define __local_dec(l) ((l)->a.counter++)
-#define __local_add(i, l) ((l)->a.counter+=(i))
-#define __local_sub(i, l) ((l)->a.counter-=(i))
-
-#endif /* _ARCH_MIPS_LOCAL_H */
Index: linux-2.6/arch/mn10300/include/asm/local.h
===================================================================
--- linux-2.6.orig/arch/mn10300/include/asm/local.h 2009-11-13 09:33:04.000000000 -0600
+++ /dev/null 1970-01-01 00:00:00.000000000 +0000
@@ -1 +0,0 @@
-#include <asm-generic/local.h>
Index: linux-2.6/arch/parisc/include/asm/local.h
===================================================================
--- linux-2.6.orig/arch/parisc/include/asm/local.h 2009-11-13 09:33:04.000000000 -0600
+++ /dev/null 1970-01-01 00:00:00.000000000 +0000
@@ -1 +0,0 @@
-#include <asm-generic/local.h>
Index: linux-2.6/arch/powerpc/include/asm/local.h
===================================================================
--- linux-2.6.orig/arch/powerpc/include/asm/local.h 2010-01-05 15:35:34.000000000 -0600
+++ /dev/null 1970-01-01 00:00:00.000000000 +0000
@@ -1,175 +0,0 @@
-#ifndef _ARCH_POWERPC_LOCAL_H
-#define _ARCH_POWERPC_LOCAL_H
-
-#include <linux/percpu.h>
-#include <asm/atomic.h>
-
-typedef struct
-{
- atomic_long_t a;
-} local_t;
-
-#define LOCAL_INIT(i) { ATOMIC_LONG_INIT(i) }
-
-#define local_read(l) atomic_long_read(&(l)->a)
-#define local_set(l,i) atomic_long_set(&(l)->a, (i))
-
-#define local_add(i,l) atomic_long_add((i),(&(l)->a))
-#define local_sub(i,l) atomic_long_sub((i),(&(l)->a))
-#define local_inc(l) atomic_long_inc(&(l)->a)
-#define local_dec(l) atomic_long_dec(&(l)->a)
-
-static __inline__ long local_add_return(long a, local_t *l)
-{
- long t;
-
- __asm__ __volatile__(
-"1:" PPC_LLARX "%0,0,%2 # local_add_return\n\
- add %0,%1,%0\n"
- PPC405_ERR77(0,%2)
- PPC_STLCX "%0,0,%2 \n\
- bne- 1b"
- : "=&r" (t)
- : "r" (a), "r" (&(l->a.counter))
- : "cc", "memory");
-
- return t;
-}
-
-#define local_add_negative(a, l) (local_add_return((a), (l)) < 0)
-
-static __inline__ long local_sub_return(long a, local_t *l)
-{
- long t;
-
- __asm__ __volatile__(
-"1:" PPC_LLARX "%0,0,%2 # local_sub_return\n\
- subf %0,%1,%0\n"
- PPC405_ERR77(0,%2)
- PPC_STLCX "%0,0,%2 \n\
- bne- 1b"
- : "=&r" (t)
- : "r" (a), "r" (&(l->a.counter))
- : "cc", "memory");
-
- return t;
-}
-
-static __inline__ long local_inc_return(local_t *l)
-{
- long t;
-
- __asm__ __volatile__(
-"1:" PPC_LLARX "%0,0,%1 # local_inc_return\n\
- addic %0,%0,1\n"
- PPC405_ERR77(0,%1)
- PPC_STLCX "%0,0,%1 \n\
- bne- 1b"
- : "=&r" (t)
- : "r" (&(l->a.counter))
- : "cc", "xer", "memory");
-
- return t;
-}
-
-/*
- * local_inc_and_test - increment and test
- * @l: pointer of type local_t
- *
- * Atomically increments @l by 1
- * and returns true if the result is zero, or false for all
- * other cases.
- */
-#define local_inc_and_test(l) (local_inc_return(l) == 0)
-
-static __inline__ long local_dec_return(local_t *l)
-{
- long t;
-
- __asm__ __volatile__(
-"1:" PPC_LLARX "%0,0,%1 # local_dec_return\n\
- addic %0,%0,-1\n"
- PPC405_ERR77(0,%1)
- PPC_STLCX "%0,0,%1\n\
- bne- 1b"
- : "=&r" (t)
- : "r" (&(l->a.counter))
- : "cc", "xer", "memory");
-
- return t;
-}
-
-#define local_cmpxchg(l, o, n) \
- (cmpxchg_local(&((l)->a.counter), (o), (n)))
-#define local_xchg(l, n) (xchg_local(&((l)->a.counter), (n)))
-
-/**
- * local_add_unless - add unless the number is a given value
- * @l: pointer of type local_t
- * @a: the amount to add to v...
- * @u: ...unless v is equal to u.
- *
- * Atomically adds @a to @l, so long as it was not @u.
- * Returns non-zero if @l was not @u, and zero otherwise.
- */
-static __inline__ int local_add_unless(local_t *l, long a, long u)
-{
- long t;
-
- __asm__ __volatile__ (
-"1:" PPC_LLARX "%0,0,%1 # local_add_unless\n\
- cmpw 0,%0,%3 \n\
- beq- 2f \n\
- add %0,%2,%0 \n"
- PPC405_ERR77(0,%2)
- PPC_STLCX "%0,0,%1 \n\
- bne- 1b \n"
-" subf %0,%2,%0 \n\
-2:"
- : "=&r" (t)
- : "r" (&(l->a.counter)), "r" (a), "r" (u)
- : "cc", "memory");
-
- return t != u;
-}
-
-#define local_inc_not_zero(l) local_add_unless((l), 1, 0)
-
-#define local_sub_and_test(a, l) (local_sub_return((a), (l)) == 0)
-#define local_dec_and_test(l) (local_dec_return((l)) == 0)
-
-/*
- * Atomically test *l and decrement if it is greater than 0.
- * The function returns the old value of *l minus 1.
- */
-static __inline__ long local_dec_if_positive(local_t *l)
-{
- long t;
-
- __asm__ __volatile__(
-"1:" PPC_LLARX "%0,0,%1 # local_dec_if_positive\n\
- cmpwi %0,1\n\
- addi %0,%0,-1\n\
- blt- 2f\n"
- PPC405_ERR77(0,%1)
- PPC_STLCX "%0,0,%1\n\
- bne- 1b"
- "\n\
-2:" : "=&b" (t)
- : "r" (&(l->a.counter))
- : "cc", "memory");
-
- return t;
-}
-
-/* Use these for per-cpu local_t variables: on some archs they are
- * much more efficient than these naive implementations. Note they take
- * a variable, not an address.
- */
-
-#define __local_inc(l) ((l)->a.counter++)
-#define __local_dec(l) ((l)->a.counter++)
-#define __local_add(i,l) ((l)->a.counter+=(i))
-#define __local_sub(i,l) ((l)->a.counter-=(i))
-
-#endif /* _ARCH_POWERPC_LOCAL_H */
Index: linux-2.6/arch/s390/include/asm/local.h
===================================================================
--- linux-2.6.orig/arch/s390/include/asm/local.h 2009-11-13 09:33:06.000000000 -0600
+++ /dev/null 1970-01-01 00:00:00.000000000 +0000
@@ -1 +0,0 @@
-#include <asm-generic/local.h>
Index: linux-2.6/arch/score/include/asm/local.h
===================================================================
--- linux-2.6.orig/arch/score/include/asm/local.h 2009-11-13 09:33:06.000000000 -0600
+++ /dev/null 1970-01-01 00:00:00.000000000 +0000
@@ -1,6 +0,0 @@
-#ifndef _ASM_SCORE_LOCAL_H
-#define _ASM_SCORE_LOCAL_H
-
-#include <asm-generic/local.h>
-
-#endif /* _ASM_SCORE_LOCAL_H */
Index: linux-2.6/arch/sh/include/asm/local.h
===================================================================
--- linux-2.6.orig/arch/sh/include/asm/local.h 2009-11-13 09:33:07.000000000 -0600
+++ /dev/null 1970-01-01 00:00:00.000000000 +0000
@@ -1,7 +0,0 @@
-#ifndef __ASM_SH_LOCAL_H
-#define __ASM_SH_LOCAL_H
-
-#include <asm-generic/local.h>
-
-#endif /* __ASM_SH_LOCAL_H */
-
Index: linux-2.6/arch/sparc/include/asm/local.h
===================================================================
--- linux-2.6.orig/arch/sparc/include/asm/local.h 2009-11-13 09:33:07.000000000 -0600
+++ /dev/null 1970-01-01 00:00:00.000000000 +0000
@@ -1,6 +0,0 @@
-#ifndef _SPARC_LOCAL_H
-#define _SPARC_LOCAL_H
-
-#include <asm-generic/local.h>
-
-#endif
Index: linux-2.6/arch/x86/include/asm/local.h
===================================================================
--- linux-2.6.orig/arch/x86/include/asm/local.h 2010-01-05 15:35:34.000000000 -0600
+++ /dev/null 1970-01-01 00:00:00.000000000 +0000
@@ -1,198 +0,0 @@
-#ifndef _ASM_X86_LOCAL_H
-#define _ASM_X86_LOCAL_H
-
-#include <linux/percpu.h>
-
-#include <asm/system.h>
-#include <asm/atomic.h>
-#include <asm/asm.h>
-
-typedef struct {
- atomic_long_t a;
-} local_t;
-
-#define LOCAL_INIT(i) { ATOMIC_LONG_INIT(i) }
-
-#define local_read(l) atomic_long_read(&(l)->a)
-#define local_set(l, i) atomic_long_set(&(l)->a, (i))
-
-static inline void local_inc(local_t *l)
-{
- asm volatile(_ASM_INC "%0"
- : "+m" (l->a.counter));
-}
-
-static inline void local_dec(local_t *l)
-{
- asm volatile(_ASM_DEC "%0"
- : "+m" (l->a.counter));
-}
-
-static inline void local_add(long i, local_t *l)
-{
- asm volatile(_ASM_ADD "%1,%0"
- : "+m" (l->a.counter)
- : "ir" (i));
-}
-
-static inline void local_sub(long i, local_t *l)
-{
- asm volatile(_ASM_SUB "%1,%0"
- : "+m" (l->a.counter)
- : "ir" (i));
-}
-
-/**
- * local_sub_and_test - subtract value from variable and test result
- * @i: integer value to subtract
- * @l: pointer to type local_t
- *
- * Atomically subtracts @i from @l and returns
- * true if the result is zero, or false for all
- * other cases.
- */
-static inline int local_sub_and_test(long i, local_t *l)
-{
- unsigned char c;
-
- asm volatile(_ASM_SUB "%2,%0; sete %1"
- : "+m" (l->a.counter), "=qm" (c)
- : "ir" (i) : "memory");
- return c;
-}
-
-/**
- * local_dec_and_test - decrement and test
- * @l: pointer to type local_t
- *
- * Atomically decrements @l by 1 and
- * returns true if the result is 0, or false for all other
- * cases.
- */
-static inline int local_dec_and_test(local_t *l)
-{
- unsigned char c;
-
- asm volatile(_ASM_DEC "%0; sete %1"
- : "+m" (l->a.counter), "=qm" (c)
- : : "memory");
- return c != 0;
-}
-
-/**
- * local_inc_and_test - increment and test
- * @l: pointer to type local_t
- *
- * Atomically increments @l by 1
- * and returns true if the result is zero, or false for all
- * other cases.
- */
-static inline int local_inc_and_test(local_t *l)
-{
- unsigned char c;
-
- asm volatile(_ASM_INC "%0; sete %1"
- : "+m" (l->a.counter), "=qm" (c)
- : : "memory");
- return c != 0;
-}
-
-/**
- * local_add_negative - add and test if negative
- * @i: integer value to add
- * @l: pointer to type local_t
- *
- * Atomically adds @i to @l and returns true
- * if the result is negative, or false when
- * result is greater than or equal to zero.
- */
-static inline int local_add_negative(long i, local_t *l)
-{
- unsigned char c;
-
- asm volatile(_ASM_ADD "%2,%0; sets %1"
- : "+m" (l->a.counter), "=qm" (c)
- : "ir" (i) : "memory");
- return c;
-}
-
-/**
- * local_add_return - add and return
- * @i: integer value to add
- * @l: pointer to type local_t
- *
- * Atomically adds @i to @l and returns @i + @l
- */
-static inline long local_add_return(long i, local_t *l)
-{
- long __i;
-#ifdef CONFIG_M386
- unsigned long flags;
- if (unlikely(boot_cpu_data.x86 <= 3))
- goto no_xadd;
-#endif
- /* Modern 486+ processor */
- __i = i;
- asm volatile(_ASM_XADD "%0, %1;"
- : "+r" (i), "+m" (l->a.counter)
- : : "memory");
- return i + __i;
-
-#ifdef CONFIG_M386
-no_xadd: /* Legacy 386 processor */
- local_irq_save(flags);
- __i = local_read(l);
- local_set(l, i + __i);
- local_irq_restore(flags);
- return i + __i;
-#endif
-}
-
-static inline long local_sub_return(long i, local_t *l)
-{
- return local_add_return(-i, l);
-}
-
-#define local_inc_return(l) (local_add_return(1, l))
-#define local_dec_return(l) (local_sub_return(1, l))
-
-#define local_cmpxchg(l, o, n) \
- (cmpxchg_local(&((l)->a.counter), (o), (n)))
-/* Always has a lock prefix */
-#define local_xchg(l, n) (xchg(&((l)->a.counter), (n)))
-
-/**
- * local_add_unless - add unless the number is a given value
- * @l: pointer of type local_t
- * @a: the amount to add to l...
- * @u: ...unless l is equal to u.
- *
- * Atomically adds @a to @l, so long as it was not @u.
- * Returns non-zero if @l was not @u, and zero otherwise.
- */
-#define local_add_unless(l, a, u) \
-({ \
- long c, old; \
- c = local_read((l)); \
- for (;;) { \
- if (unlikely(c == (u))) \
- break; \
- old = local_cmpxchg((l), c, c + (a)); \
- if (likely(old == c)) \
- break; \
- c = old; \
- } \
- c != (u); \
-})
-#define local_inc_not_zero(l) local_add_unless((l), 1, 0)
-
-/* On x86_32, these are no better than the atomic variants.
- * On x86-64 these are better than the atomic variants on SMP kernels
- * because they dont use a lock prefix.
- */
-#define __local_inc(l) local_inc(l)
-#define __local_dec(l) local_dec(l)
-#define __local_add(i, l) local_add((i), (l))
-#define __local_sub(i, l) local_sub((i), (l))
-
-#endif /* _ASM_X86_LOCAL_H */
Index: linux-2.6/arch/xtensa/include/asm/local.h
===================================================================
--- linux-2.6.orig/arch/xtensa/include/asm/local.h 2009-11-13 09:33:18.000000000 -0600
+++ /dev/null 1970-01-01 00:00:00.000000000 +0000
@@ -1,16 +0,0 @@
-/*
- * include/asm-xtensa/local.h
- *
- * This file is subject to the terms and conditions of the GNU General Public
- * License. See the file "COPYING" in the main directory of this archive
- * for more details.
- *
- * Copyright (C) 2001 - 2005 Tensilica Inc.
- */
-
-#ifndef _XTENSA_LOCAL_H
-#define _XTENSA_LOCAL_H
-
-#include <asm-generic/local.h>
-
-#endif /* _XTENSA_LOCAL_H */
Index: linux-2.6/Documentation/atomic_ops.txt
===================================================================
--- linux-2.6.orig/Documentation/atomic_ops.txt 2009-11-13 09:32:52.000000000 -0600
+++ linux-2.6/Documentation/atomic_ops.txt 2010-01-05 15:41:03.000000000 -0600
@@ -17,9 +17,10 @@ suffice:
Historically, counter has been declared volatile. This is now discouraged.
See Documentation/volatile-considered-harmful.txt for the complete rationale.
-local_t is very similar to atomic_t. If the counter is per CPU and only
-updated by one CPU, local_t is probably more appropriate. Please see
-Documentation/local_ops.txt for the semantics of local_t.
+this_cpu operations are very similar to atomic_t. If the counter is per CPU
+and only updated by one CPU, then the use of the per cpu allocator and
+this cpu operations is more appropriate. Please see include/linux/percpu.h
+for details.
The first operations to implement for atomic_t's are the initializers and
plain reads.
Index: linux-2.6/Documentation/local_ops.txt
===================================================================
--- linux-2.6.orig/Documentation/local_ops.txt 2009-11-13 09:32:52.000000000 -0600
+++ /dev/null 1970-01-01 00:00:00.000000000 +0000
@@ -1,186 +0,0 @@
- Semantics and Behavior of Local Atomic Operations
-
- Mathieu Desnoyers
-
-
- This document explains the purpose of the local atomic operations, how
-to implement them for any given architecture and shows how they can be used
-properly. It also stresses on the precautions that must be taken when reading
-those local variables across CPUs when the order of memory writes matters.
-
-
-
-* Purpose of local atomic operations
-
-Local atomic operations are meant to provide fast and highly reentrant per CPU
-counters. They minimize the performance cost of standard atomic operations by
-removing the LOCK prefix and memory barriers normally required to synchronize
-across CPUs.
-
-Having fast per CPU atomic counters is interesting in many cases : it does not
-require disabling interrupts to protect from interrupt handlers and it permits
-coherent counters in NMI handlers. It is especially useful for tracing purposes
-and for various performance monitoring counters.
-
-Local atomic operations only guarantee variable modification atomicity wrt the
-CPU which owns the data. Therefore, care must taken to make sure that only one
-CPU writes to the local_t data. This is done by using per cpu data and making
-sure that we modify it from within a preemption safe context. It is however
-permitted to read local_t data from any CPU : it will then appear to be written
-out of order wrt other memory writes by the owner CPU.
-
-
-* Implementation for a given architecture
-
-It can be done by slightly modifying the standard atomic operations : only
-their UP variant must be kept. It typically means removing LOCK prefix (on
-i386 and x86_64) and any SMP synchronization barrier. If the architecture does
-not have a different behavior between SMP and UP, including asm-generic/local.h
-in your architecture's local.h is sufficient.
-
-The local_t type is defined as an opaque signed long by embedding an
-atomic_long_t inside a structure. This is made so a cast from this type to a
-long fails. The definition looks like :
-
-typedef struct { atomic_long_t a; } local_t;
-
-
-* Rules to follow when using local atomic operations
-
-- Variables touched by local ops must be per cpu variables.
-- _Only_ the CPU owner of these variables must write to them.
-- This CPU can use local ops from any context (process, irq, softirq, nmi, ...)
- to update its local_t variables.
-- Preemption (or interrupts) must be disabled when using local ops in
- process context to make sure the process won't be migrated to a
- different CPU between getting the per-cpu variable and doing the
- actual local op.
-- When using local ops in interrupt context, no special care must be
- taken on a mainline kernel, since they will run on the local CPU with
- preemption already disabled. I suggest, however, to explicitly
- disable preemption anyway to make sure it will still work correctly on
- -rt kernels.
-- Reading the local cpu variable will provide the current copy of the
- variable.
-- Reads of these variables can be done from any CPU, because updates to
- "long", aligned, variables are always atomic. Since no memory
- synchronization is done by the writer CPU, an outdated copy of the
- variable can be read when reading some _other_ cpu's variables.
-
-
-* How to use local atomic operations
-
-#include <linux/percpu.h>
-#include <asm/local.h>
-
-static DEFINE_PER_CPU(local_t, counters) = LOCAL_INIT(0);
-
-
-* Counting
-
-Counting is done on all the bits of a signed long.
-
-In preemptible context, use get_cpu_var() and put_cpu_var() around local atomic
-operations : it makes sure that preemption is disabled around write access to
-the per cpu variable. For instance :
-
- local_inc(&get_cpu_var(counters));
- put_cpu_var(counters);
-
-If you are already in a preemption-safe context, you can directly use
-__get_cpu_var() instead.
-
- local_inc(&__get_cpu_var(counters));
-
-
-
-* Reading the counters
-
-Those local counters can be read from foreign CPUs to sum the count. Note that
-the data seen by local_read across CPUs must be considered to be out of order
-relatively to other memory writes happening on the CPU that owns the data.
-
- long sum = 0;
- for_each_online_cpu(cpu)
- sum += local_read(&per_cpu(counters, cpu));
-
-If you want to use a remote local_read to synchronize access to a resource
-between CPUs, explicit smp_wmb() and smp_rmb() memory barriers must be used
-respectively on the writer and the reader CPUs. It would be the case if you use
-the local_t variable as a counter of bytes written in a buffer : there should
-be a smp_wmb() between the buffer write and the counter increment and also a
-smp_rmb() between the counter read and the buffer read.
-
-
-Here is a sample module which implements a basic per cpu counter using local.h.
-
---- BEGIN ---
-/* test-local.c
- *
- * Sample module for local.h usage.
- */
-
-
-#include <asm/local.h>
-#include <linux/module.h>
-#include <linux/timer.h>
-
-static DEFINE_PER_CPU(local_t, counters) = LOCAL_INIT(0);
-
-static struct timer_list test_timer;
-
-/* IPI called on each CPU. */
-static void test_each(void *info)
-{
- /* Increment the counter from a non preemptible context */
- printk("Increment on cpu %d\n", smp_processor_id());
- local_inc(&__get_cpu_var(counters));
-
- /* This is what incrementing the variable would look like within a
- * preemptible context (it disables preemption) :
- *
- * local_inc(&get_cpu_var(counters));
- * put_cpu_var(counters);
- */
-}
-
-static void do_test_timer(unsigned long data)
-{
- int cpu;
-
- /* Increment the counters */
- on_each_cpu(test_each, NULL, 1);
- /* Read all the counters */
- printk("Counters read from CPU %d\n", smp_processor_id());
- for_each_online_cpu(cpu) {
- printk("Read : CPU %d, count %ld\n", cpu,
- local_read(&per_cpu(counters, cpu)));
- }
- del_timer(&test_timer);
- test_timer.expires = jiffies + 1000;
- add_timer(&test_timer);
-}
-
-static int __init test_init(void)
-{
- /* initialize the timer that will increment the counter */
- init_timer(&test_timer);
- test_timer.function = do_test_timer;
- test_timer.expires = jiffies + 1;
- add_timer(&test_timer);
-
- return 0;
-}
-
-static void __exit test_exit(void)
-{
- del_timer_sync(&test_timer);
-}
-
-module_init(test_init);
-module_exit(test_exit);
-
-MODULE_LICENSE("GPL");
-MODULE_AUTHOR("Mathieu Desnoyers");
-MODULE_DESCRIPTION("Local Atomic Ops");
---- END ---
Index: linux-2.6/Documentation/DocBook/kernel-locking.tmpl
===================================================================
--- linux-2.6.orig/Documentation/DocBook/kernel-locking.tmpl 2009-11-13 09:32:52.000000000 -0600
+++ linux-2.6/Documentation/DocBook/kernel-locking.tmpl 2010-01-05 15:41:03.000000000 -0600
@@ -1810,14 +1810,6 @@ machines due to caching.
</para>
<para>
- Of particular use for simple per-cpu counters is the
- <type>local_t</type> type, and the
- <function>cpu_local_inc()</function> and related functions,
- which are more efficient than simple code on some architectures
- (<filename class="headerfile">include/asm/local.h</filename>).
- </para>
-
- <para>
Note that there is no simple, reliable way of getting an exact
value of such a counter, without introducing more locks. This
is not a problem for some uses.
Index: linux-2.6/include/asm-generic/local.h
===================================================================
--- linux-2.6.orig/include/asm-generic/local.h 2010-01-05 15:35:34.000000000 -0600
+++ /dev/null 1970-01-01 00:00:00.000000000 +0000
@@ -1,55 +0,0 @@
-#ifndef _ASM_GENERIC_LOCAL_H
-#define _ASM_GENERIC_LOCAL_H
-
-#include <linux/percpu.h>
-#include <asm/atomic.h>
-#include <asm/types.h>
-
-/*
- * A signed long type for operations which are atomic for a single CPU.
- * Usually used in combination with per-cpu variables.
- *
- * This is the default implementation, which uses atomic_long_t. Which is
- * rather pointless. The whole point behind local_t is that some processors
- * can perform atomic adds and subtracts in a manner which is atomic wrt IRQs
- * running on this CPU. local_t allows exploitation of such capabilities.
- */
-
-/* Implement in terms of atomics. */
-
-/* Don't use typedef: don't want them to be mixed with atomic_t's. */
-typedef struct
-{
- atomic_long_t a;
-} local_t;
-
-#define LOCAL_INIT(i) { ATOMIC_LONG_INIT(i) }
-
-#define local_read(l) atomic_long_read(&(l)->a)
-#define local_set(l,i) atomic_long_set((&(l)->a),(i))
-#define local_inc(l) atomic_long_inc(&(l)->a)
-#define local_dec(l) atomic_long_dec(&(l)->a)
-#define local_add(i,l) atomic_long_add((i),(&(l)->a))
-#define local_sub(i,l) atomic_long_sub((i),(&(l)->a))
-
-#define local_sub_and_test(i, l) atomic_long_sub_and_test((i), (&(l)->a))
-#define local_dec_and_test(l) atomic_long_dec_and_test(&(l)->a)
-#define local_inc_and_test(l) atomic_long_inc_and_test(&(l)->a)
-#define local_add_negative(i, l) atomic_long_add_negative((i), (&(l)->a))
-#define local_add_return(i, l) atomic_long_add_return((i), (&(l)->a))
-#define local_sub_return(i, l) atomic_long_sub_return((i), (&(l)->a))
-#define local_inc_return(l) atomic_long_inc_return(&(l)->a)
-
-#define local_cmpxchg(l, o, n) atomic_long_cmpxchg((&(l)->a), (o), (n))
-#define local_xchg(l, n) atomic_long_xchg((&(l)->a), (n))
-#define local_add_unless(l, _a, u) atomic_long_add_unless((&(l)->a), (_a), (u))
-#define local_inc_not_zero(l) atomic_long_inc_not_zero(&(l)->a)
-
-/* Non-atomic variants, ie. preemption disabled and won't be touched
- * in interrupt, etc. Some archs can optimize this case well. */
-#define __local_inc(l) local_set((l), local_read(l) + 1)
-#define __local_dec(l) local_set((l), local_read(l) - 1)
-#define __local_add(i,l) local_set((l), local_read(l) + (i))
-#define __local_sub(i,l) local_set((l), local_read(l) - (i))
-
-#endif /* _ASM_GENERIC_LOCAL_H */
--
next prev parent reply other threads:[~2010-01-05 22:06 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-01-05 22:04 [RFC local_t removal V1 0/4] Remove local_t Christoph Lameter
2010-01-05 22:04 ` [RFC local_t removal V1 1/4] Add add_local() and add_local_return() Christoph Lameter
2010-01-05 22:17 ` Mike Frysinger
2010-01-05 22:29 ` Christoph Lameter
2010-01-06 19:23 ` Mike Frysinger
2010-01-07 17:03 ` Christoph Lameter
2010-01-05 22:49 ` Mathieu Desnoyers
2010-01-07 13:45 ` Arnd Bergmann
2010-01-07 13:57 ` Mathieu Desnoyers
2010-01-07 14:22 ` Arnd Bergmann
2010-01-07 17:07 ` Christoph Lameter
2010-01-05 22:04 ` [RFC local_t removal V1 2/4] Replace local_t use in trace subsystem Christoph Lameter
2010-01-05 22:57 ` Mathieu Desnoyers
2010-01-07 17:15 ` Christoph Lameter
2010-01-14 2:56 ` Steven Rostedt
2010-01-14 14:49 ` Christoph Lameter
2010-01-05 22:04 ` [RFC local_t removal V1 3/4] Optimized add_local() Christoph Lameter
2010-01-05 22:59 ` Mathieu Desnoyers
2010-01-07 17:16 ` Christoph Lameter
2010-01-05 22:04 ` Christoph Lameter [this message]
2010-01-05 22:23 ` [RFC local_t removal V1 0/4] Remove local_t Mathieu Desnoyers
2010-01-05 22:34 ` Christoph Lameter
2010-01-05 22:45 ` Mathieu Desnoyers
2010-01-07 17:05 ` Christoph Lameter
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20100105220439.566620901@quilx.com \
--to=cl@linux-foundation.org \
--cc=mathieu.desnoyers@polymtl.ca \
--cc=tj@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.