f8cbd99bd3
This patch adds a new preemption model: 'Voluntary Kernel Preemption'. The
3 models can be selected from a new menu:
(X) No Forced Preemption (Server)
( ) Voluntary Kernel Preemption (Desktop)
( ) Preemptible Kernel (Low-Latency Desktop)
we still default to the stock (Server) preemption model.
Voluntary preemption works by adding a cond_resched()
(reschedule-if-needed) call to every might_sleep() check. It is lighter
than CONFIG_PREEMPT - at the cost of not having as tight latencies. It
represents a different latency/complexity/overhead tradeoff.
It has no runtime impact at all if disabled. Here are size stats that show
how the various preemption models impact the kernel's size:
text data bss dec hex filename
3618774 547184 179896 4345854 424ffe vmlinux.stock
3626406 547184 179896 4353486 426dce vmlinux.voluntary +0.2%
3748414 548640 179896 4476950 445016 vmlinux.preempt +3.5%
voluntary-preempt is +0.2% of .text, preempt is +3.5%.
This feature has been tested for many months by lots of people (and it's
also included in the RHEL4 distribution and earlier variants were in Fedora
as well), and it's intended for users and distributions who dont want to
use full-blown CONFIG_PREEMPT for one reason or another.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
325 lines
9.2 KiB
C
325 lines
9.2 KiB
C
#ifndef _LINUX_KERNEL_H
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#define _LINUX_KERNEL_H
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/*
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* 'kernel.h' contains some often-used function prototypes etc
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*/
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#ifdef __KERNEL__
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#include <stdarg.h>
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#include <linux/linkage.h>
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#include <linux/stddef.h>
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#include <linux/types.h>
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#include <linux/compiler.h>
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#include <linux/bitops.h>
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#include <asm/byteorder.h>
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#include <asm/bug.h>
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extern const char linux_banner[];
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#define INT_MAX ((int)(~0U>>1))
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#define INT_MIN (-INT_MAX - 1)
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#define UINT_MAX (~0U)
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#define LONG_MAX ((long)(~0UL>>1))
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#define LONG_MIN (-LONG_MAX - 1)
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#define ULONG_MAX (~0UL)
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#define STACK_MAGIC 0xdeadbeef
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#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
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#define ALIGN(x,a) (((x)+(a)-1)&~((a)-1))
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#define KERN_EMERG "<0>" /* system is unusable */
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#define KERN_ALERT "<1>" /* action must be taken immediately */
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#define KERN_CRIT "<2>" /* critical conditions */
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#define KERN_ERR "<3>" /* error conditions */
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#define KERN_WARNING "<4>" /* warning conditions */
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#define KERN_NOTICE "<5>" /* normal but significant condition */
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#define KERN_INFO "<6>" /* informational */
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#define KERN_DEBUG "<7>" /* debug-level messages */
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extern int console_printk[];
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#define console_loglevel (console_printk[0])
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#define default_message_loglevel (console_printk[1])
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#define minimum_console_loglevel (console_printk[2])
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#define default_console_loglevel (console_printk[3])
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struct completion;
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/**
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* might_sleep - annotation for functions that can sleep
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*
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* this macro will print a stack trace if it is executed in an atomic
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* context (spinlock, irq-handler, ...).
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*
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* This is a useful debugging help to be able to catch problems early and not
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* be biten later when the calling function happens to sleep when it is not
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* supposed to.
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*/
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#ifdef CONFIG_PREEMPT_VOLUNTARY
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extern int cond_resched(void);
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# define might_resched() cond_resched()
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#else
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# define might_resched() do { } while (0)
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#endif
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#ifdef CONFIG_DEBUG_SPINLOCK_SLEEP
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void __might_sleep(char *file, int line);
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# define might_sleep() \
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do { __might_sleep(__FILE__, __LINE__); might_resched(); } while (0)
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#else
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# define might_sleep() do { might_resched(); } while (0)
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#endif
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#define might_sleep_if(cond) do { if (unlikely(cond)) might_sleep(); } while (0)
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#define abs(x) ({ \
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int __x = (x); \
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(__x < 0) ? -__x : __x; \
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})
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#define labs(x) ({ \
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long __x = (x); \
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(__x < 0) ? -__x : __x; \
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})
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extern struct notifier_block *panic_notifier_list;
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extern long (*panic_blink)(long time);
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NORET_TYPE void panic(const char * fmt, ...)
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__attribute__ ((NORET_AND format (printf, 1, 2)));
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fastcall NORET_TYPE void do_exit(long error_code)
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ATTRIB_NORET;
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NORET_TYPE void complete_and_exit(struct completion *, long)
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ATTRIB_NORET;
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extern unsigned long simple_strtoul(const char *,char **,unsigned int);
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extern long simple_strtol(const char *,char **,unsigned int);
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extern unsigned long long simple_strtoull(const char *,char **,unsigned int);
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extern long long simple_strtoll(const char *,char **,unsigned int);
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extern int sprintf(char * buf, const char * fmt, ...)
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__attribute__ ((format (printf, 2, 3)));
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extern int vsprintf(char *buf, const char *, va_list)
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__attribute__ ((format (printf, 2, 0)));
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extern int snprintf(char * buf, size_t size, const char * fmt, ...)
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__attribute__ ((format (printf, 3, 4)));
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extern int vsnprintf(char *buf, size_t size, const char *fmt, va_list args)
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__attribute__ ((format (printf, 3, 0)));
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extern int scnprintf(char * buf, size_t size, const char * fmt, ...)
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__attribute__ ((format (printf, 3, 4)));
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extern int vscnprintf(char *buf, size_t size, const char *fmt, va_list args)
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__attribute__ ((format (printf, 3, 0)));
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extern int sscanf(const char *, const char *, ...)
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__attribute__ ((format (scanf, 2, 3)));
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extern int vsscanf(const char *, const char *, va_list)
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__attribute__ ((format (scanf, 2, 0)));
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extern int get_option(char **str, int *pint);
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extern char *get_options(const char *str, int nints, int *ints);
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extern unsigned long long memparse(char *ptr, char **retptr);
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extern int __kernel_text_address(unsigned long addr);
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extern int kernel_text_address(unsigned long addr);
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extern int session_of_pgrp(int pgrp);
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#ifdef CONFIG_PRINTK
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asmlinkage int vprintk(const char *fmt, va_list args)
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__attribute__ ((format (printf, 1, 0)));
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asmlinkage int printk(const char * fmt, ...)
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__attribute__ ((format (printf, 1, 2)));
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#else
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static inline int vprintk(const char *s, va_list args)
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__attribute__ ((format (printf, 1, 0)));
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static inline int vprintk(const char *s, va_list args) { return 0; }
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static inline int printk(const char *s, ...)
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__attribute__ ((format (printf, 1, 2)));
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static inline int printk(const char *s, ...) { return 0; }
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#endif
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unsigned long int_sqrt(unsigned long);
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static inline int __attribute_pure__ long_log2(unsigned long x)
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{
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int r = 0;
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for (x >>= 1; x > 0; x >>= 1)
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r++;
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return r;
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}
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static inline unsigned long __attribute_const__ roundup_pow_of_two(unsigned long x)
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{
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return (1UL << fls(x - 1));
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}
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extern int printk_ratelimit(void);
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extern int __printk_ratelimit(int ratelimit_jiffies, int ratelimit_burst);
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static inline void console_silent(void)
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{
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console_loglevel = 0;
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}
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static inline void console_verbose(void)
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{
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if (console_loglevel)
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console_loglevel = 15;
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}
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extern void bust_spinlocks(int yes);
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extern int oops_in_progress; /* If set, an oops, panic(), BUG() or die() is in progress */
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extern int panic_timeout;
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extern int panic_on_oops;
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extern int tainted;
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extern const char *print_tainted(void);
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extern void add_taint(unsigned);
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/* Values used for system_state */
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extern enum system_states {
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SYSTEM_BOOTING,
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SYSTEM_RUNNING,
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SYSTEM_HALT,
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SYSTEM_POWER_OFF,
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SYSTEM_RESTART,
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} system_state;
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#define TAINT_PROPRIETARY_MODULE (1<<0)
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#define TAINT_FORCED_MODULE (1<<1)
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#define TAINT_UNSAFE_SMP (1<<2)
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#define TAINT_FORCED_RMMOD (1<<3)
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#define TAINT_MACHINE_CHECK (1<<4)
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#define TAINT_BAD_PAGE (1<<5)
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extern void dump_stack(void);
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#ifdef DEBUG
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#define pr_debug(fmt,arg...) \
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printk(KERN_DEBUG fmt,##arg)
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#else
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#define pr_debug(fmt,arg...) \
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do { } while (0)
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#endif
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#define pr_info(fmt,arg...) \
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printk(KERN_INFO fmt,##arg)
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/*
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* Display an IP address in readable format.
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*/
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#define NIPQUAD(addr) \
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((unsigned char *)&addr)[0], \
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((unsigned char *)&addr)[1], \
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((unsigned char *)&addr)[2], \
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((unsigned char *)&addr)[3]
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#define NIP6(addr) \
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ntohs((addr).s6_addr16[0]), \
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ntohs((addr).s6_addr16[1]), \
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ntohs((addr).s6_addr16[2]), \
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ntohs((addr).s6_addr16[3]), \
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ntohs((addr).s6_addr16[4]), \
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ntohs((addr).s6_addr16[5]), \
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ntohs((addr).s6_addr16[6]), \
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ntohs((addr).s6_addr16[7])
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#if defined(__LITTLE_ENDIAN)
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#define HIPQUAD(addr) \
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((unsigned char *)&addr)[3], \
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((unsigned char *)&addr)[2], \
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((unsigned char *)&addr)[1], \
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((unsigned char *)&addr)[0]
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#elif defined(__BIG_ENDIAN)
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#define HIPQUAD NIPQUAD
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#else
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#error "Please fix asm/byteorder.h"
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#endif /* __LITTLE_ENDIAN */
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/*
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* min()/max() macros that also do
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* strict type-checking.. See the
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* "unnecessary" pointer comparison.
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*/
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#define min(x,y) ({ \
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typeof(x) _x = (x); \
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typeof(y) _y = (y); \
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(void) (&_x == &_y); \
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_x < _y ? _x : _y; })
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#define max(x,y) ({ \
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typeof(x) _x = (x); \
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typeof(y) _y = (y); \
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(void) (&_x == &_y); \
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_x > _y ? _x : _y; })
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/*
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* ..and if you can't take the strict
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* types, you can specify one yourself.
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*
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* Or not use min/max at all, of course.
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*/
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#define min_t(type,x,y) \
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({ type __x = (x); type __y = (y); __x < __y ? __x: __y; })
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#define max_t(type,x,y) \
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({ type __x = (x); type __y = (y); __x > __y ? __x: __y; })
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/**
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* container_of - cast a member of a structure out to the containing structure
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*
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* @ptr: the pointer to the member.
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* @type: the type of the container struct this is embedded in.
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* @member: the name of the member within the struct.
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*
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*/
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#define container_of(ptr, type, member) ({ \
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const typeof( ((type *)0)->member ) *__mptr = (ptr); \
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(type *)( (char *)__mptr - offsetof(type,member) );})
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/*
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* Check at compile time that something is of a particular type.
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* Always evaluates to 1 so you may use it easily in comparisons.
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*/
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#define typecheck(type,x) \
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({ type __dummy; \
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typeof(x) __dummy2; \
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(void)(&__dummy == &__dummy2); \
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1; \
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})
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#endif /* __KERNEL__ */
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#define SI_LOAD_SHIFT 16
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struct sysinfo {
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long uptime; /* Seconds since boot */
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unsigned long loads[3]; /* 1, 5, and 15 minute load averages */
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unsigned long totalram; /* Total usable main memory size */
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unsigned long freeram; /* Available memory size */
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unsigned long sharedram; /* Amount of shared memory */
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unsigned long bufferram; /* Memory used by buffers */
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unsigned long totalswap; /* Total swap space size */
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unsigned long freeswap; /* swap space still available */
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unsigned short procs; /* Number of current processes */
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unsigned short pad; /* explicit padding for m68k */
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unsigned long totalhigh; /* Total high memory size */
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unsigned long freehigh; /* Available high memory size */
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unsigned int mem_unit; /* Memory unit size in bytes */
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char _f[20-2*sizeof(long)-sizeof(int)]; /* Padding: libc5 uses this.. */
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};
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extern void BUILD_BUG(void);
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#define BUILD_BUG_ON(condition) do { if (condition) BUILD_BUG(); } while(0)
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#ifdef CONFIG_SYSCTL
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extern int randomize_va_space;
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#else
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#define randomize_va_space 1
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#endif
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/* Trap pasters of __FUNCTION__ at compile-time */
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#if __GNUC__ > 2 || __GNUC_MINOR__ >= 95
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#define __FUNCTION__ (__func__)
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#endif
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#endif
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