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
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