/*
   * tsacct.c - System accounting over taskstats interface
   *
   * Copyright (C) Jay Lan,	<jlan@sgi.com>
   *
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License as published by
   * the Free Software Foundation; either version 2 of the License, or
   * (at your option) any later version.
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   *
   */
  
  #include <linux/kernel.h>
  #include <linux/sched.h>
  #include <linux/tsacct_kern.h>
  #include <linux/acct.h>

  #include <linux/jiffies.h>

  #include <linux/mm.h>

  /*
   * fill in basic accounting fields
   */

  void bacct_add_tsk(struct user_namespace *user_ns,
  		   struct pid_namespace *pid_ns,
  		   struct taskstats *stats, struct task_struct *tsk)

  {

  	const struct cred *tcred;

  	struct timespec uptime, ts;

  	cputime_t utime, stime, utimescaled, stimescaled;

  	u64 ac_etime;

  
  	BUILD_BUG_ON(TS_COMM_LEN < TASK_COMM_LEN);
  
  	/* calculate task elapsed time in timespec */
  	do_posix_clock_monotonic_gettime(&uptime);

  	ts = timespec_sub(uptime, tsk->start_time);

  	/* rebase elapsed time to usec (should never be negative) */

  	ac_etime = timespec_to_ns(&ts);
  	do_div(ac_etime, NSEC_PER_USEC);
  	stats->ac_etime = ac_etime;

  	stats->ac_btime = get_seconds() - ts.tv_sec;

  	if (thread_group_leader(tsk)) {
  		stats->ac_exitcode = tsk->exit_code;
  		if (tsk->flags & PF_FORKNOEXEC)
  			stats->ac_flag |= AFORK;
  	}
  	if (tsk->flags & PF_SUPERPRIV)
  		stats->ac_flag |= ASU;
  	if (tsk->flags & PF_DUMPCORE)
  		stats->ac_flag |= ACORE;
  	if (tsk->flags & PF_SIGNALED)
  		stats->ac_flag |= AXSIG;
  	stats->ac_nice	 = task_nice(tsk);
  	stats->ac_sched	 = tsk->policy;

  	stats->ac_pid	 = task_pid_nr_ns(tsk, pid_ns);

  	rcu_read_lock();

  	tcred = __task_cred(tsk);

  	stats->ac_uid	 = from_kuid_munged(user_ns, tcred->uid);
  	stats->ac_gid	 = from_kgid_munged(user_ns, tcred->gid);

  	stats->ac_ppid	 = pid_alive(tsk) ?

  		task_tgid_nr_ns(rcu_dereference(tsk->real_parent), pid_ns) : 0;

  	rcu_read_unlock();

  
  	task_cputime(tsk, &utime, &stime);
  	stats->ac_utime = cputime_to_usecs(utime);
  	stats->ac_stime = cputime_to_usecs(stime);
  
  	task_cputime_scaled(tsk, &utimescaled, &stimescaled);
  	stats->ac_utimescaled = cputime_to_usecs(utimescaled);
  	stats->ac_stimescaled = cputime_to_usecs(stimescaled);

  	stats->ac_minflt = tsk->min_flt;
  	stats->ac_majflt = tsk->maj_flt;

  
  	strncpy(stats->ac_comm, tsk->comm, sizeof(stats->ac_comm));
  }

  
  #ifdef CONFIG_TASK_XACCT

  
  #define KB 1024
  #define MB (1024*KB)

  #define KB_MASK (~(KB-1))

  /*
   * fill in extended accounting fields
   */
  void xacct_add_tsk(struct taskstats *stats, struct task_struct *p)
  {

  	struct mm_struct *mm;

  	/* convert pages-usec to Mbyte-usec */
  	stats->coremem = p->acct_rss_mem1 * PAGE_SIZE / MB;
  	stats->virtmem = p->acct_vm_mem1 * PAGE_SIZE / MB;

  	mm = get_task_mm(p);
  	if (mm) {

  		/* adjust to KB unit */

  		stats->hiwater_rss   = get_mm_hiwater_rss(mm) * PAGE_SIZE / KB;
  		stats->hiwater_vm    = get_mm_hiwater_vm(mm)  * PAGE_SIZE / KB;

  		mmput(mm);

  	}

  	stats->read_char	= p->ioac.rchar & KB_MASK;
  	stats->write_char	= p->ioac.wchar & KB_MASK;
  	stats->read_syscalls	= p->ioac.syscr & KB_MASK;
  	stats->write_syscalls	= p->ioac.syscw & KB_MASK;

  #ifdef CONFIG_TASK_IO_ACCOUNTING

  	stats->read_bytes	= p->ioac.read_bytes & KB_MASK;
  	stats->write_bytes	= p->ioac.write_bytes & KB_MASK;
  	stats->cancelled_write_bytes = p->ioac.cancelled_write_bytes & KB_MASK;

  #else
  	stats->read_bytes	= 0;
  	stats->write_bytes	= 0;
  	stats->cancelled_write_bytes = 0;
  #endif

  }

  #undef KB
  #undef MB

  static void __acct_update_integrals(struct task_struct *tsk,
  				    cputime_t utime, cputime_t stime)

  {
  	if (likely(tsk->mm)) {

  		cputime_t time, dtime;
  		struct timeval value;

  		unsigned long flags;

  		u64 delta;

  		local_irq_save(flags);

  		time = stime + utime;

  		dtime = time - tsk->acct_timexpd;

  		jiffies_to_timeval(cputime_to_jiffies(dtime), &value);
  		delta = value.tv_sec;
  		delta = delta * USEC_PER_SEC + value.tv_usec;

  
  		if (delta == 0)

  			goto out;

  		tsk->acct_timexpd = time;

  		tsk->acct_rss_mem1 += delta * get_mm_rss(tsk->mm);
  		tsk->acct_vm_mem1 += delta * tsk->mm->total_vm;

  	out:
  		local_irq_restore(flags);

  	}
  }
  
  /**

   * acct_update_integrals - update mm integral fields in task_struct
   * @tsk: task_struct for accounting
   */
  void acct_update_integrals(struct task_struct *tsk)
  {
  	cputime_t utime, stime;
  
  	task_cputime(tsk, &utime, &stime);
  	__acct_update_integrals(tsk, utime, stime);
  }
  
  /**
   * acct_account_cputime - update mm integral after cputime update
   * @tsk: task_struct for accounting
   */
  void acct_account_cputime(struct task_struct *tsk)
  {
  	__acct_update_integrals(tsk, tsk->utime, tsk->stime);
  }
  
  /**

   * acct_clear_integrals - clear the mm integral fields in task_struct
   * @tsk: task_struct whose accounting fields are cleared
   */
  void acct_clear_integrals(struct task_struct *tsk)
  {

  	tsk->acct_timexpd = 0;

  	tsk->acct_rss_mem1 = 0;
  	tsk->acct_vm_mem1 = 0;
  }

  #endif