6ffc787a44
The kernel has a divide by zero crash when trying to run the system timer less than 100Hz. The problem is x/(HZ/USER_HZ) and related. Now x*(USER_HZ/HZ) will be used if HZ<USER_HZ. I'm running the Linux kernel under qemu and went to run a slower system timer to take less CPU (and battery) on the host. I found that the kernel paniced under emulation because of a divide by zero in three places. Here is the patch. The base git was updated today 01-05-2008. I went for a 20Hz system time by adding config HZ_20 etc to kernel/Kconfig.hz. With this patch I verified the system timer by looking at /proc/interrupts. [akpm@linux-foundation.org: partially clean up the macro maze] Signed-off-by: David Fries <david@fries.net> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
210 lines
5.7 KiB
C
210 lines
5.7 KiB
C
/*
|
|
* BSD Process Accounting for Linux - Definitions
|
|
*
|
|
* Author: Marco van Wieringen (mvw@planets.elm.net)
|
|
*
|
|
* This header file contains the definitions needed to implement
|
|
* BSD-style process accounting. The kernel accounting code and all
|
|
* user-level programs that try to do something useful with the
|
|
* process accounting log must include this file.
|
|
*
|
|
* Copyright (C) 1995 - 1997 Marco van Wieringen - ELM Consultancy B.V.
|
|
*
|
|
*/
|
|
|
|
#ifndef _LINUX_ACCT_H
|
|
#define _LINUX_ACCT_H
|
|
|
|
#include <linux/types.h>
|
|
|
|
#include <asm/param.h>
|
|
#include <asm/byteorder.h>
|
|
|
|
/*
|
|
* comp_t is a 16-bit "floating" point number with a 3-bit base 8
|
|
* exponent and a 13-bit fraction.
|
|
* comp2_t is 24-bit with 5-bit base 2 exponent and 20 bit fraction
|
|
* (leading 1 not stored).
|
|
* See linux/kernel/acct.c for the specific encoding systems used.
|
|
*/
|
|
|
|
typedef __u16 comp_t;
|
|
typedef __u32 comp2_t;
|
|
|
|
/*
|
|
* accounting file record
|
|
*
|
|
* This structure contains all of the information written out to the
|
|
* process accounting file whenever a process exits.
|
|
*/
|
|
|
|
#define ACCT_COMM 16
|
|
|
|
struct acct
|
|
{
|
|
char ac_flag; /* Flags */
|
|
char ac_version; /* Always set to ACCT_VERSION */
|
|
/* for binary compatibility back until 2.0 */
|
|
__u16 ac_uid16; /* LSB of Real User ID */
|
|
__u16 ac_gid16; /* LSB of Real Group ID */
|
|
__u16 ac_tty; /* Control Terminal */
|
|
__u32 ac_btime; /* Process Creation Time */
|
|
comp_t ac_utime; /* User Time */
|
|
comp_t ac_stime; /* System Time */
|
|
comp_t ac_etime; /* Elapsed Time */
|
|
comp_t ac_mem; /* Average Memory Usage */
|
|
comp_t ac_io; /* Chars Transferred */
|
|
comp_t ac_rw; /* Blocks Read or Written */
|
|
comp_t ac_minflt; /* Minor Pagefaults */
|
|
comp_t ac_majflt; /* Major Pagefaults */
|
|
comp_t ac_swaps; /* Number of Swaps */
|
|
/* m68k had no padding here. */
|
|
#if !defined(CONFIG_M68K) || !defined(__KERNEL__)
|
|
__u16 ac_ahz; /* AHZ */
|
|
#endif
|
|
__u32 ac_exitcode; /* Exitcode */
|
|
char ac_comm[ACCT_COMM + 1]; /* Command Name */
|
|
__u8 ac_etime_hi; /* Elapsed Time MSB */
|
|
__u16 ac_etime_lo; /* Elapsed Time LSB */
|
|
__u32 ac_uid; /* Real User ID */
|
|
__u32 ac_gid; /* Real Group ID */
|
|
};
|
|
|
|
struct acct_v3
|
|
{
|
|
char ac_flag; /* Flags */
|
|
char ac_version; /* Always set to ACCT_VERSION */
|
|
__u16 ac_tty; /* Control Terminal */
|
|
__u32 ac_exitcode; /* Exitcode */
|
|
__u32 ac_uid; /* Real User ID */
|
|
__u32 ac_gid; /* Real Group ID */
|
|
__u32 ac_pid; /* Process ID */
|
|
__u32 ac_ppid; /* Parent Process ID */
|
|
__u32 ac_btime; /* Process Creation Time */
|
|
#ifdef __KERNEL__
|
|
__u32 ac_etime; /* Elapsed Time */
|
|
#else
|
|
float ac_etime; /* Elapsed Time */
|
|
#endif
|
|
comp_t ac_utime; /* User Time */
|
|
comp_t ac_stime; /* System Time */
|
|
comp_t ac_mem; /* Average Memory Usage */
|
|
comp_t ac_io; /* Chars Transferred */
|
|
comp_t ac_rw; /* Blocks Read or Written */
|
|
comp_t ac_minflt; /* Minor Pagefaults */
|
|
comp_t ac_majflt; /* Major Pagefaults */
|
|
comp_t ac_swaps; /* Number of Swaps */
|
|
char ac_comm[ACCT_COMM]; /* Command Name */
|
|
};
|
|
|
|
/*
|
|
* accounting flags
|
|
*/
|
|
/* bit set when the process ... */
|
|
#define AFORK 0x01 /* ... executed fork, but did not exec */
|
|
#define ASU 0x02 /* ... used super-user privileges */
|
|
#define ACOMPAT 0x04 /* ... used compatibility mode (VAX only not used) */
|
|
#define ACORE 0x08 /* ... dumped core */
|
|
#define AXSIG 0x10 /* ... was killed by a signal */
|
|
|
|
#ifdef __BIG_ENDIAN
|
|
#define ACCT_BYTEORDER 0x80 /* accounting file is big endian */
|
|
#else
|
|
#define ACCT_BYTEORDER 0x00 /* accounting file is little endian */
|
|
#endif
|
|
|
|
#ifdef __KERNEL__
|
|
|
|
|
|
#ifdef CONFIG_BSD_PROCESS_ACCT
|
|
struct vfsmount;
|
|
struct super_block;
|
|
struct pacct_struct;
|
|
extern void acct_auto_close_mnt(struct vfsmount *m);
|
|
extern void acct_auto_close(struct super_block *sb);
|
|
extern void acct_init_pacct(struct pacct_struct *pacct);
|
|
extern void acct_collect(long exitcode, int group_dead);
|
|
extern void acct_process(void);
|
|
#else
|
|
#define acct_auto_close_mnt(x) do { } while (0)
|
|
#define acct_auto_close(x) do { } while (0)
|
|
#define acct_init_pacct(x) do { } while (0)
|
|
#define acct_collect(x,y) do { } while (0)
|
|
#define acct_process() do { } while (0)
|
|
#endif
|
|
|
|
/*
|
|
* ACCT_VERSION numbers as yet defined:
|
|
* 0: old format (until 2.6.7) with 16 bit uid/gid
|
|
* 1: extended variant (binary compatible on M68K)
|
|
* 2: extended variant (binary compatible on everything except M68K)
|
|
* 3: new binary incompatible format (64 bytes)
|
|
* 4: new binary incompatible format (128 bytes)
|
|
* 5: new binary incompatible format (128 bytes, second half)
|
|
*
|
|
*/
|
|
|
|
#ifdef CONFIG_BSD_PROCESS_ACCT_V3
|
|
#define ACCT_VERSION 3
|
|
#define AHZ 100
|
|
typedef struct acct_v3 acct_t;
|
|
#else
|
|
#ifdef CONFIG_M68K
|
|
#define ACCT_VERSION 1
|
|
#else
|
|
#define ACCT_VERSION 2
|
|
#endif
|
|
#define AHZ (USER_HZ)
|
|
typedef struct acct acct_t;
|
|
#endif
|
|
|
|
#else
|
|
#define ACCT_VERSION 2
|
|
#define AHZ (HZ)
|
|
#endif /* __KERNEL */
|
|
|
|
#ifdef __KERNEL__
|
|
#include <linux/jiffies.h>
|
|
/*
|
|
* Yet another set of HZ to *HZ helper functions.
|
|
* See <linux/jiffies.h> for the original.
|
|
*/
|
|
|
|
static inline u32 jiffies_to_AHZ(unsigned long x)
|
|
{
|
|
#if (TICK_NSEC % (NSEC_PER_SEC / AHZ)) == 0
|
|
# if HZ < AHZ
|
|
return x * (AHZ / HZ);
|
|
# else
|
|
return x / (HZ / AHZ);
|
|
# endif
|
|
#else
|
|
u64 tmp = (u64)x * TICK_NSEC;
|
|
do_div(tmp, (NSEC_PER_SEC / AHZ));
|
|
return (long)tmp;
|
|
#endif
|
|
}
|
|
|
|
static inline u64 nsec_to_AHZ(u64 x)
|
|
{
|
|
#if (NSEC_PER_SEC % AHZ) == 0
|
|
do_div(x, (NSEC_PER_SEC / AHZ));
|
|
#elif (AHZ % 512) == 0
|
|
x *= AHZ/512;
|
|
do_div(x, (NSEC_PER_SEC / 512));
|
|
#else
|
|
/*
|
|
* max relative error 5.7e-8 (1.8s per year) for AHZ <= 1024,
|
|
* overflow after 64.99 years.
|
|
* exact for AHZ=60, 72, 90, 120, 144, 180, 300, 600, 900, ...
|
|
*/
|
|
x *= 9;
|
|
do_div(x, (unsigned long)((9ull * NSEC_PER_SEC + (AHZ/2))
|
|
/ AHZ));
|
|
#endif
|
|
return x;
|
|
}
|
|
|
|
#endif /* __KERNEL */
|
|
|
|
#endif /* _LINUX_ACCT_H */
|