CRED: Use RCU to access another task's creds and to release a task's own creds
[GitHub/mt8127/android_kernel_alcatel_ttab.git] / kernel / tsacct.c
1 /*
2 * tsacct.c - System accounting over taskstats interface
3 *
4 * Copyright (C) Jay Lan, <jlan@sgi.com>
5 *
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
16 *
17 */
18
19 #include <linux/kernel.h>
20 #include <linux/sched.h>
21 #include <linux/tsacct_kern.h>
22 #include <linux/acct.h>
23 #include <linux/jiffies.h>
24
25 /*
26 * fill in basic accounting fields
27 */
28 void bacct_add_tsk(struct taskstats *stats, struct task_struct *tsk)
29 {
30 const struct cred *tcred;
31 struct timespec uptime, ts;
32 u64 ac_etime;
33
34 BUILD_BUG_ON(TS_COMM_LEN < TASK_COMM_LEN);
35
36 /* calculate task elapsed time in timespec */
37 do_posix_clock_monotonic_gettime(&uptime);
38 ts = timespec_sub(uptime, tsk->start_time);
39 /* rebase elapsed time to usec (should never be negative) */
40 ac_etime = timespec_to_ns(&ts);
41 do_div(ac_etime, NSEC_PER_USEC);
42 stats->ac_etime = ac_etime;
43 stats->ac_btime = get_seconds() - ts.tv_sec;
44 if (thread_group_leader(tsk)) {
45 stats->ac_exitcode = tsk->exit_code;
46 if (tsk->flags & PF_FORKNOEXEC)
47 stats->ac_flag |= AFORK;
48 }
49 if (tsk->flags & PF_SUPERPRIV)
50 stats->ac_flag |= ASU;
51 if (tsk->flags & PF_DUMPCORE)
52 stats->ac_flag |= ACORE;
53 if (tsk->flags & PF_SIGNALED)
54 stats->ac_flag |= AXSIG;
55 stats->ac_nice = task_nice(tsk);
56 stats->ac_sched = tsk->policy;
57 stats->ac_pid = tsk->pid;
58 rcu_read_lock();
59 tcred = __task_cred(tsk);
60 stats->ac_uid = tcred->uid;
61 stats->ac_gid = tcred->gid;
62 stats->ac_ppid = pid_alive(tsk) ?
63 rcu_dereference(tsk->real_parent)->tgid : 0;
64 rcu_read_unlock();
65 stats->ac_utime = cputime_to_msecs(tsk->utime) * USEC_PER_MSEC;
66 stats->ac_stime = cputime_to_msecs(tsk->stime) * USEC_PER_MSEC;
67 stats->ac_utimescaled =
68 cputime_to_msecs(tsk->utimescaled) * USEC_PER_MSEC;
69 stats->ac_stimescaled =
70 cputime_to_msecs(tsk->stimescaled) * USEC_PER_MSEC;
71 stats->ac_minflt = tsk->min_flt;
72 stats->ac_majflt = tsk->maj_flt;
73
74 strncpy(stats->ac_comm, tsk->comm, sizeof(stats->ac_comm));
75 }
76
77
78 #ifdef CONFIG_TASK_XACCT
79
80 #define KB 1024
81 #define MB (1024*KB)
82 /*
83 * fill in extended accounting fields
84 */
85 void xacct_add_tsk(struct taskstats *stats, struct task_struct *p)
86 {
87 struct mm_struct *mm;
88
89 /* convert pages-usec to Mbyte-usec */
90 stats->coremem = p->acct_rss_mem1 * PAGE_SIZE / MB;
91 stats->virtmem = p->acct_vm_mem1 * PAGE_SIZE / MB;
92 mm = get_task_mm(p);
93 if (mm) {
94 /* adjust to KB unit */
95 stats->hiwater_rss = mm->hiwater_rss * PAGE_SIZE / KB;
96 stats->hiwater_vm = mm->hiwater_vm * PAGE_SIZE / KB;
97 mmput(mm);
98 }
99 stats->read_char = p->ioac.rchar;
100 stats->write_char = p->ioac.wchar;
101 stats->read_syscalls = p->ioac.syscr;
102 stats->write_syscalls = p->ioac.syscw;
103 #ifdef CONFIG_TASK_IO_ACCOUNTING
104 stats->read_bytes = p->ioac.read_bytes;
105 stats->write_bytes = p->ioac.write_bytes;
106 stats->cancelled_write_bytes = p->ioac.cancelled_write_bytes;
107 #else
108 stats->read_bytes = 0;
109 stats->write_bytes = 0;
110 stats->cancelled_write_bytes = 0;
111 #endif
112 }
113 #undef KB
114 #undef MB
115
116 /**
117 * acct_update_integrals - update mm integral fields in task_struct
118 * @tsk: task_struct for accounting
119 */
120 void acct_update_integrals(struct task_struct *tsk)
121 {
122 if (likely(tsk->mm)) {
123 cputime_t time, dtime;
124 struct timeval value;
125 u64 delta;
126
127 time = tsk->stime + tsk->utime;
128 dtime = cputime_sub(time, tsk->acct_timexpd);
129 jiffies_to_timeval(cputime_to_jiffies(dtime), &value);
130 delta = value.tv_sec;
131 delta = delta * USEC_PER_SEC + value.tv_usec;
132
133 if (delta == 0)
134 return;
135 tsk->acct_timexpd = time;
136 tsk->acct_rss_mem1 += delta * get_mm_rss(tsk->mm);
137 tsk->acct_vm_mem1 += delta * tsk->mm->total_vm;
138 }
139 }
140
141 /**
142 * acct_clear_integrals - clear the mm integral fields in task_struct
143 * @tsk: task_struct whose accounting fields are cleared
144 */
145 void acct_clear_integrals(struct task_struct *tsk)
146 {
147 tsk->acct_timexpd = 0;
148 tsk->acct_rss_mem1 = 0;
149 tsk->acct_vm_mem1 = 0;
150 }
151 #endif