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Commit 4b98d11b authored by Alexey Dobriyan's avatar Alexey Dobriyan Committed by Linus Torvalds
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[PATCH] ifdef ->rchar, ->wchar, ->syscr, ->syscw from task_struct 



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: default avatarAlexey Dobriyan <adobriyan@gmail.com>
Cc: Jay Lan <jlan@engr.sgi.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 18f705f4

fs/proc/base.c

+4 −0
Original line number Diff line number Diff line
@@ -1810,17 +1810,21 @@ static int proc_base_fill_cache(struct file *filp, void *dirent, filldir_t filld 
static int proc_pid_io_accounting(struct task_struct *task, char *buffer)

{

	return sprintf(buffer,

#ifdef CONFIG_TASK_XACCT

			"rchar: %llu\n"

			"wchar: %llu\n"

			"syscr: %llu\n"

			"syscw: %llu\n"

#endif

			"read_bytes: %llu\n"

			"write_bytes: %llu\n"

			"cancelled_write_bytes: %llu\n",

#ifdef CONFIG_TASK_XACCT

			(unsigned long long)task->rchar,

			(unsigned long long)task->wchar,

			(unsigned long long)task->syscr,

			(unsigned long long)task->syscw,

#endif

			(unsigned long long)task->ioac.read_bytes,

			(unsigned long long)task->ioac.write_bytes,

			(unsigned long long)task->ioac.cancelled_write_bytes);

fs/read_write.c

+12 −12
Original line number Diff line number Diff line
@@ -274,9 +274,9 @@ ssize_t vfs_read(struct file *file, char __user *buf, size_t count, loff_t *pos) 
				ret = do_sync_read(file, buf, count, pos);

			if (ret > 0) {

				fsnotify_access(file->f_path.dentry);

				current->rchar += ret;

				add_rchar(current, ret);

			}

			current->syscr++;

			inc_syscr(current);

		}

	}
@@ -332,9 +332,9 @@ ssize_t vfs_write(struct file *file, const char __user *buf, size_t count, loff_ 
				ret = do_sync_write(file, buf, count, pos);

			if (ret > 0) {

				fsnotify_modify(file->f_path.dentry);

				current->wchar += ret;

				add_wchar(current, ret);

			}

			current->syscw++;

			inc_syscw(current);

		}

	}
@@ -675,8 +675,8 @@ sys_readv(unsigned long fd, const struct iovec __user *vec, unsigned long vlen) 
	}



	if (ret > 0)

		current->rchar += ret;

	current->syscr++;

		add_rchar(current, ret);

	inc_syscr(current);

	return ret;

}
@@ -696,8 +696,8 @@ sys_writev(unsigned long fd, const struct iovec __user *vec, unsigned long vlen) 
	}



	if (ret > 0)

		current->wchar += ret;

	current->syscw++;

		add_wchar(current, ret);

	inc_syscw(current);

	return ret;

}
@@ -779,12 +779,12 @@ static ssize_t do_sendfile(int out_fd, int in_fd, loff_t *ppos, 
	retval = in_file->f_op->sendfile(in_file, ppos, count, file_send_actor, out_file);



	if (retval > 0) {

		current->rchar += retval;

		current->wchar += retval;

		add_rchar(current, retval);

		add_wchar(current, retval);

	}

	current->syscr++;

	current->syscw++;



	inc_syscr(current);

	inc_syscw(current);

	if (*ppos > max)

		retval = -EOVERFLOW;

include/linux/sched.h

+40 −0
Original line number Diff line number Diff line
@@ -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

kernel/fork.c

+2 −0
Original line number Diff line number Diff line
@@ -1038,10 +1038,12 @@ static struct task_struct *copy_process(unsigned long clone_flags, 
	p->utime = cputime_zero;

	p->stime = cputime_zero;

 	p->sched_time = 0;

#ifdef CONFIG_TASK_XACCT

	p->rchar = 0;		/* I/O counter: bytes read */

	p->wchar = 0;		/* I/O counter: bytes written */

	p->syscr = 0;		/* I/O counter: read syscalls */

	p->syscw = 0;		/* I/O counter: write syscalls */

#endif

	task_io_accounting_init(p);

	acct_clear_integrals(p);