Commit 5995477a authored by Andrea Righi's avatar Andrea Righi Committed by Linus Torvalds
Browse files

task IO accounting: improve code readability 



Put all i/o statistics in struct proc_io_accounting and use inline functions to
initialize and increment statistics, removing a lot of single variable
assignments.

This also reduces the kernel size as following (with CONFIG_TASK_XACCT=y and
CONFIG_TASK_IO_ACCOUNTING=y).

    text    data     bss     dec     hex filename
   11651       0       0   11651    2d83 kernel/exit.o.before
   11619       0       0   11619    2d63 kernel/exit.o.after
   10886     132     136   11154    2b92 kernel/fork.o.before
   10758     132     136   11026    2b12 kernel/fork.o.after

 3082029  807968 4818600 8708597  84e1f5 vmlinux.o.before
 3081869  807968 4818600 8708437  84e155 vmlinux.o.after

Signed-off-by: default avatarAndrea Righi <righi.andrea@gmail.com>
Acked-by: default avatarOleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 605ccb73

fs/proc/base.c

+16 −41
Original line number Diff line number Diff line
@@ -53,6 +53,7 @@ 
#include <linux/time.h>

#include <linux/proc_fs.h>

#include <linux/stat.h>

#include <linux/task_io_accounting_ops.h>

#include <linux/init.h>

#include <linux/capability.h>

#include <linux/file.h>
@@ -2402,45 +2403,18 @@ static int proc_base_fill_cache(struct file *filp, void *dirent, 
#ifdef CONFIG_TASK_IO_ACCOUNTING

static int do_io_accounting(struct task_struct *task, char *buffer, int whole)

{

	u64 rchar, wchar, syscr, syscw;

	struct task_io_accounting ioac;



	rchar = task->rchar;

	wchar = task->wchar;

	syscr = task->syscr;

	syscw = task->syscw;

	memcpy(&ioac, &task->ioac, sizeof(ioac));



	if (whole) {

	struct proc_io_accounting acct = task->ioac;

	unsigned long flags;



		if (lock_task_sighand(task, &flags)) {

			struct signal_struct *sig = task->signal;

	if (whole && lock_task_sighand(task, &flags)) {

		struct task_struct *t = task;



			rchar += sig->rchar;

			wchar += sig->wchar;

			syscr += sig->syscr;

			syscw += sig->syscw;



			ioac.read_bytes += sig->ioac.read_bytes;

			ioac.write_bytes += sig->ioac.write_bytes;

			ioac.cancelled_write_bytes +=

					sig->ioac.cancelled_write_bytes;

			while_each_thread(task, t) {

				rchar += t->rchar;

				wchar += t->wchar;

				syscr += t->syscr;

				syscw += t->syscw;



				ioac.read_bytes += t->ioac.read_bytes;

				ioac.write_bytes += t->ioac.write_bytes;

				ioac.cancelled_write_bytes +=

					t->ioac.cancelled_write_bytes;

			}

		task_io_accounting_add(&acct, &task->signal->ioac);

		while_each_thread(task, t)

			task_io_accounting_add(&acct, &t->ioac);



		unlock_task_sighand(task, &flags);

	}

	}

	return sprintf(buffer,

			"rchar: %llu\n"

			"wchar: %llu\n"
@@ -2449,9 +2423,10 @@ static int do_io_accounting(struct task_struct *task, char *buffer, int whole) 
			"read_bytes: %llu\n"

			"write_bytes: %llu\n"

			"cancelled_write_bytes: %llu\n",

			rchar, wchar, syscr, syscw,

			ioac.read_bytes, ioac.write_bytes,

			ioac.cancelled_write_bytes);

			acct.chr.rchar, acct.chr.wchar,

			acct.chr.syscr, acct.chr.syscw,

			acct.blk.read_bytes, acct.blk.write_bytes,

			acct.blk.cancelled_write_bytes);

}



static int proc_tid_io_accounting(struct task_struct *task, char *buffer)

include/linux/sched.h

+6 −13
Original line number Diff line number Diff line
@@ -505,10 +505,7 @@ struct signal_struct { 
	unsigned long nvcsw, nivcsw, cnvcsw, cnivcsw;

	unsigned long min_flt, maj_flt, cmin_flt, cmaj_flt;

	unsigned long inblock, oublock, cinblock, coublock;

#ifdef CONFIG_TASK_XACCT

	u64 rchar, wchar, syscr, syscw;

#endif

	struct task_io_accounting ioac;

	struct proc_io_accounting ioac;



	/*

	 * Cumulative ns of scheduled CPU time for dead threads in the
@@ -1256,11 +1253,7 @@ struct task_struct { 


	unsigned long ptrace_message;

	siginfo_t *last_siginfo; /* For ptrace use.  */

#ifdef CONFIG_TASK_XACCT

/* i/o counters(bytes read/written, #syscalls */

	u64 rchar, wchar, syscr, syscw;

#endif

	struct task_io_accounting ioac;

	struct proc_io_accounting ioac;

#if defined(CONFIG_TASK_XACCT)

	u64 acct_rss_mem1;	/* accumulated rss usage */

	u64 acct_vm_mem1;	/* accumulated virtual memory usage */
@@ -2190,22 +2183,22 @@ extern long sched_group_rt_period(struct task_group *tg); 
#ifdef CONFIG_TASK_XACCT

static inline void add_rchar(struct task_struct *tsk, ssize_t amt)

{

	tsk->rchar += amt;

	tsk->ioac.chr.rchar += amt;

}



static inline void add_wchar(struct task_struct *tsk, ssize_t amt)

{

	tsk->wchar += amt;

	tsk->ioac.chr.wchar += amt;

}



static inline void inc_syscr(struct task_struct *tsk)

{

	tsk->syscr++;

	tsk->ioac.chr.syscr++;

}



static inline void inc_syscw(struct task_struct *tsk)

{

	tsk->syscw++;

	tsk->ioac.chr.syscw++;

}

#else

static inline void add_rchar(struct task_struct *tsk, ssize_t amt)

include/linux/task_io_accounting.h

+24 −3
Original line number Diff line number Diff line 
/*

 * task_io_accounting: a structure which is used for recording a single task's

 * proc_io_accounting: a structure which is used for recording a single task's

 * IO statistics.

 *

 * Don't include this header file directly - it is designed to be dragged in via
@@ -8,6 +8,22 @@ 
 * Blame akpm@osdl.org for all this.

 */



#ifdef CONFIG_TASK_XACCT

struct task_chr_io_accounting {

	/* bytes read */

	u64 rchar;

	/*  bytes written */

	u64 wchar;

	/* # of read syscalls */

	u64 syscr;

	/* # of write syscalls */

	u64 syscw;

};

#else /* CONFIG_TASK_XACCT */

struct task_chr_io_accounting {

};

#endif /* CONFIG_TASK_XACCT */



#ifdef CONFIG_TASK_IO_ACCOUNTING

struct task_io_accounting {

	/*
@@ -31,7 +47,12 @@ struct task_io_accounting { 
	 */

	u64 cancelled_write_bytes;

};

#else

#else /* CONFIG_TASK_IO_ACCOUNTING */

struct task_io_accounting {

};

#endif
 
#endif /* CONFIG_TASK_IO_ACCOUNTING */



struct proc_io_accounting {

	struct task_chr_io_accounting chr;

	struct task_io_accounting blk;

};

include/linux/task_io_accounting_ops.h

+46 −10
Original line number Diff line number Diff line
@@ -9,7 +9,7 @@ 
#ifdef CONFIG_TASK_IO_ACCOUNTING

static inline void task_io_account_read(size_t bytes)

{

	current->ioac.read_bytes += bytes;

	current->ioac.blk.read_bytes += bytes;

}



/*
@@ -18,12 +18,12 @@ static inline void task_io_account_read(size_t bytes) 
 */

static inline unsigned long task_io_get_inblock(const struct task_struct *p)

{

	return p->ioac.read_bytes >> 9;

	return p->ioac.blk.read_bytes >> 9;

}



static inline void task_io_account_write(size_t bytes)

{

	current->ioac.write_bytes += bytes;

	current->ioac.blk.write_bytes += bytes;

}



/*
@@ -32,17 +32,25 @@ static inline void task_io_account_write(size_t bytes) 
 */

static inline unsigned long task_io_get_oublock(const struct task_struct *p)

{

	return p->ioac.write_bytes >> 9;

	return p->ioac.blk.write_bytes >> 9;

}



static inline void task_io_account_cancelled_write(size_t bytes)

{

	current->ioac.cancelled_write_bytes += bytes;

	current->ioac.blk.cancelled_write_bytes += bytes;

}



static inline void task_io_accounting_init(struct task_struct *tsk)

static inline void task_io_accounting_init(struct proc_io_accounting *ioac)

{

	memset(&tsk->ioac, 0, sizeof(tsk->ioac));

	memset(ioac, 0, sizeof(*ioac));

}



static inline void task_blk_io_accounting_add(struct proc_io_accounting *dst,

						struct proc_io_accounting *src)

{

	dst->blk.read_bytes += src->blk.read_bytes;

	dst->blk.write_bytes += src->blk.write_bytes;

	dst->blk.cancelled_write_bytes += src->blk.cancelled_write_bytes;

}



#else
@@ -69,9 +77,37 @@ static inline void task_io_account_cancelled_write(size_t bytes) 
{

}



static inline void task_io_accounting_init(struct task_struct *tsk)

static inline void task_io_accounting_init(struct proc_io_accounting *ioac)

{

}



static inline void task_blk_io_accounting_add(struct proc_io_accounting *dst,

						struct proc_io_accounting *src)

{

}



#endif /* CONFIG_TASK_IO_ACCOUNTING */



#ifdef CONFIG_TASK_XACCT

static inline void task_chr_io_accounting_add(struct proc_io_accounting *dst,

						struct proc_io_accounting *src)

{

	dst->chr.rchar += src->chr.rchar;

	dst->chr.wchar += src->chr.wchar;

	dst->chr.syscr += src->chr.syscr;

	dst->chr.syscw += src->chr.syscw;

}

#else

static inline void task_chr_io_accounting_add(struct proc_io_accounting *dst,

						struct proc_io_accounting *src)

{

}

#endif /* CONFIG_TASK_XACCT */



static inline void task_io_accounting_add(struct proc_io_accounting *dst,

						struct proc_io_accounting *src)

{

	task_chr_io_accounting_add(dst, src);

	task_blk_io_accounting_add(dst, src);

}

#endif /* __TASK_IO_ACCOUNTING_OPS_INCLUDED */

kernel/exit.c

+3 −27
Original line number Diff line number Diff line
@@ -121,18 +121,7 @@ static void __exit_signal(struct task_struct *tsk) 
		sig->nivcsw += tsk->nivcsw;

		sig->inblock += task_io_get_inblock(tsk);

		sig->oublock += task_io_get_oublock(tsk);

#ifdef CONFIG_TASK_XACCT

		sig->rchar += tsk->rchar;

		sig->wchar += tsk->wchar;

		sig->syscr += tsk->syscr;

		sig->syscw += tsk->syscw;

#endif /* CONFIG_TASK_XACCT */

#ifdef CONFIG_TASK_IO_ACCOUNTING

		sig->ioac.read_bytes += tsk->ioac.read_bytes;

		sig->ioac.write_bytes += tsk->ioac.write_bytes;

		sig->ioac.cancelled_write_bytes +=

					tsk->ioac.cancelled_write_bytes;

#endif /* CONFIG_TASK_IO_ACCOUNTING */

		task_io_accounting_add(&sig->ioac, &tsk->ioac);

		sig->sum_sched_runtime += tsk->se.sum_exec_runtime;

		sig = NULL; /* Marker for below. */

	}
@@ -1363,21 +1352,8 @@ static int wait_task_zombie(struct task_struct *p, int options, 
		psig->coublock +=

			task_io_get_oublock(p) +

			sig->oublock + sig->coublock;

#ifdef CONFIG_TASK_XACCT

		psig->rchar += p->rchar + sig->rchar;

		psig->wchar += p->wchar + sig->wchar;

		psig->syscr += p->syscr + sig->syscr;

		psig->syscw += p->syscw + sig->syscw;

#endif /* CONFIG_TASK_XACCT */

#ifdef CONFIG_TASK_IO_ACCOUNTING

		psig->ioac.read_bytes +=

			p->ioac.read_bytes + sig->ioac.read_bytes;

		psig->ioac.write_bytes +=

			p->ioac.write_bytes + sig->ioac.write_bytes;

		psig->ioac.cancelled_write_bytes +=

				p->ioac.cancelled_write_bytes +

				sig->ioac.cancelled_write_bytes;

#endif /* CONFIG_TASK_IO_ACCOUNTING */

		task_io_accounting_add(&psig->ioac, &p->ioac);

		task_io_accounting_add(&psig->ioac, &sig->ioac);

		spin_unlock_irq(&p->parent->sighand->siglock);

	}

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