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[PATCH] ifdef ->rchar, ->wchar, ->syscr, ->syscw from task_struct

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They are fat: 4x8 bytes in task_struct.
They are uncoditionally updated in every fork, read, write and sendfile.
They are used only if you have some "extended acct fields feature".

And please, please, please, read(2) knows about bytes, not characters,
why it is called "rchar"?

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Jay Lan <jlan@engr.sgi.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Alexey Dobriyan
2007-02-10 01:46:45 -08:00
committed by Linus Torvalds
parent 18f705f49a
commit 4b98d11b40
4 changed files with 58 additions and 12 deletions
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40
include/linux/sched.h
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@@ -1013,8 +1013,10 @@ struct task_struct {
* to a stack based synchronous wait) if its doing sync IO.
*/
wait_queue_t *io_wait;
#ifdef CONFIG_TASK_XACCT
/* i/o counters(bytes read/written, #syscalls */
u64 rchar, wchar, syscr, syscw;
#endif
struct task_io_accounting ioac;
#if defined(CONFIG_TASK_XACCT)
u64 acct_rss_mem1; /* accumulated rss usage */
@@ -1649,6 +1651,44 @@ extern int sched_create_sysfs_power_savings_entries(struct sysdev_class *cls);
extern void normalize_rt_tasks(void);
#ifdef CONFIG_TASK_XACCT
static inline void add_rchar(struct task_struct *tsk, ssize_t amt)
{
tsk->rchar += amt;
}
static inline void add_wchar(struct task_struct *tsk, ssize_t amt)
{
tsk->wchar += amt;
}
static inline void inc_syscr(struct task_struct *tsk)
{
tsk->syscr++;
}
static inline void inc_syscw(struct task_struct *tsk)
{
tsk->syscw++;
}
#else
static inline void add_rchar(struct task_struct *tsk, ssize_t amt)
{
}
static inline void add_wchar(struct task_struct *tsk, ssize_t amt)
{
}
static inline void inc_syscr(struct task_struct *tsk)
{
}
static inline void inc_syscw(struct task_struct *tsk)
{
}
#endif
#endif /* __KERNEL__ */
#endif