TASKSTATS_CMD_ATTR_TGID used to return only the delay accounting stats, not
the basic and extended accounting. With this patch,
TASKSTATS_CMD_ATTR_TGID also aggregates the accounting info for all threads
of a thread group. This makes TASKSTATS_CMD_ATTR_TGID usable in a similar
fashion to TASKSTATS_CMD_ATTR_PID, for commands like iotop -P
(http://guichaz.free.fr/misc/iotop.py).
Changelog since V3 (http://lkml.org/lkml/2007/8/31/121):
- Removed userspace example, either it gets accepted in util-linux-ng or I'll
maintain it elsewhere.
- Added kerneldoc for fill_threadgroup() and add_tsk().
- Removed useless {get,put}_task_struct(leader) as spotted by Andrew Morton
and Oleg Nesterov.
- Use lock_task_sighand() instead of spin_lock_irqsave(&tsk->sighand->siglock)
for consistency with the locking of task->signal->stats in fill_tgid().
- Removed useless check for a NULL taskstats in fill_tgid_exit(). Thanks Oleg.
- Documented double accounting race seen by Oleg.
- Rephrased the fill_tgid_exit() comment as per Oleg's recommendation.
- Documented the special case for the AFORK ac_flag.
- Use the exit status (code >> 8) instead of the exit code as documented in
Documentation/accounting/taskstats-struct.txt.
- Use signal->group_exit_code if set for stats->ac_exitcode on a TGID as
suggested by Oleg.
Changelog since V2 (http://lkml.org/lkml/2007/8/19/96):
- Added a testcase
- Added an indirection between the stats producer and consumer:
add_task() & fill_threadgroup()
- TGID stats are either summed from all the threads or taken from the leader
Changelog since V1 (http://lkml.org/lkml/2007/8/2/185):
- Update combined stats of exited threads in fill_tgid_exit() as
suggested by Balbir Singh.
- Very light cleanup of fill_tgid_exit() by the way.
- bacct fields are also combined for all threads.
- Instead of assuming memory stats are identical for all threads, we
take the max of all threads.
Signed-off-by: Guillaume Chazarain <[email protected]>
Cc: Balbir Singh <[email protected]>
Cc: Jay Lan <[email protected]>
Cc: Jonathan Lim <[email protected]>
Cc: Oleg Nesterov <[email protected]>
---
include/linux/tsacct_kern.h | 12 ++
kernel/taskstats.c | 139 +++++++++++++++++++++-------------
kernel/tsacct.c | 113 +++++++++++++++------------
3 files changed, 162 insertions(+), 102 deletions(-)
diff -r ec584ed21efa include/linux/tsacct_kern.h
--- a/include/linux/tsacct_kern.h Fri Sep 14 14:04:13 2007 -0700
+++ b/include/linux/tsacct_kern.h Tue Aug 28 20:35:27 2007 +0200
@@ -10,17 +10,23 @@
#include <linux/taskstats.h>
#ifdef CONFIG_TASKSTATS
-extern void bacct_add_tsk(struct taskstats *stats, struct task_struct *tsk);
+void bacct_fill_threadgroup(struct taskstats *stats, struct task_struct *task);
+void bacct_add_tsk(struct taskstats *stats, struct task_struct *task);
#else
-static inline void bacct_add_tsk(struct taskstats *stats, struct task_struct *tsk)
+static inline void bacct_fill_threadgroup(struct taskstats *stats, struct task_struct *task)
+{}
+static inline void bacct_add_tsk(struct taskstats *stats, struct task_struct *task)
{}
#endif /* CONFIG_TASKSTATS */
#ifdef CONFIG_TASK_XACCT
-extern void xacct_add_tsk(struct taskstats *stats, struct task_struct *p);
+void xacct_fill_threadgroup(struct taskstats *stats, struct task_struct *task);
+void xacct_add_tsk(struct taskstats *stats, struct task_struct *p);
extern void acct_update_integrals(struct task_struct *tsk);
extern void acct_clear_integrals(struct task_struct *tsk);
#else
+static inline void xacct_fill_threadgroup(struct taskstats *stats, struct task_struct *task)
+{}
static inline void xacct_add_tsk(struct taskstats *stats, struct task_struct *p)
{}
static inline void acct_update_integrals(struct task_struct *tsk)
diff -r ec584ed21efa kernel/taskstats.c
--- a/kernel/taskstats.c Fri Sep 14 14:04:13 2007 -0700
+++ b/kernel/taskstats.c Sat Sep 15 20:22:47 2007 +0200
@@ -168,6 +168,68 @@ static void send_cpu_listeners(struct sk
up_write(&listeners->sem);
}
+/**
+ * fill_threadgroup - initialize some common stats for the thread group
+ * @stats: the taskstats to write into
+ * @task: the thread representing the whole group
+ *
+ * There are two types of taskstats fields when considering a thread group:
+ * - those that can be aggregated from each thread in the group (like CPU
+ * times),
+ * - those that cannot be aggregated (like UID) or are identical (like
+ * memory usage), so are taken from the group leader.
+ * XXX_threadgroup() methods deal with the first type while XXX_add_tsk() with
+ * the second.
+ */
+static void fill_threadgroup(struct taskstats *stats, struct task_struct *task)
+{
+ /*
+ * Each accounting subsystem adds calls to its functions to initialize
+ * relevant parts of struct taskstsats for a single tgid as follows:
+ *
+ * per-task-foo-fill_threadgroup(stats, task);
+ */
+
+ stats->version = TASKSTATS_VERSION;
+
+ /* fill in basic acct fields */
+ bacct_fill_threadgroup(stats, task);
+
+ /* fill in extended acct fields */
+ xacct_fill_threadgroup(stats, task);
+}
+
+/**
+ * add_tsk - combine some thread specific stats in a taskstats
+ * @stats: the taskstats to write into
+ * @task: the thread to combine
+ *
+ * Stats specific to each thread in the thread group. Stats of @task should be
+ * combined with those already present in @stats. add_tsk() works in
+ * conjunction with fill_threadgroup(), taskstats fields should not be touched
+ * by both functions.
+ */
+static void add_tsk(struct taskstats *stats, struct task_struct *task)
+{
+ /*
+ * Each accounting subsystem adds calls to its functions to combine
+ * relevant parts of struct taskstsats for a single pid as follows:
+ *
+ * per-task-foo-add_tsk(stats, task);
+ */
+ stats->nvcsw += task->nvcsw;
+ stats->nivcsw += task->nivcsw;
+
+ /* fill in delay acct fields */
+ delayacct_add_tsk(stats, task);
+
+ /* fill in basic acct fields */
+ bacct_add_tsk(stats, task);
+
+ /* fill in extended acct fields */
+ xacct_add_tsk(stats, task);
+}
+
static int fill_pid(pid_t pid, struct task_struct *tsk,
struct taskstats *stats)
{
@@ -185,23 +247,8 @@ static int fill_pid(pid_t pid, struct ta
get_task_struct(tsk);
memset(stats, 0, sizeof(*stats));
- /*
- * Each accounting subsystem adds calls to its functions to
- * fill in relevant parts of struct taskstsats as follows
- *
- * per-task-foo(stats, tsk);
- */
-
- delayacct_add_tsk(stats, tsk);
-
- /* fill in basic acct fields */
- stats->version = TASKSTATS_VERSION;
- stats->nvcsw = tsk->nvcsw;
- stats->nivcsw = tsk->nivcsw;
- bacct_add_tsk(stats, tsk);
-
- /* fill in extended acct fields */
- xacct_add_tsk(stats, tsk);
+ fill_threadgroup(stats, tsk);
+ add_tsk(stats, tsk);
/* Define err: label here if needed */
put_task_struct(tsk);
@@ -232,32 +279,25 @@ static int fill_tgid(pid_t tgid, struct
else
memset(stats, 0, sizeof(*stats));
+ fill_threadgroup(stats, first->group_leader);
+
tsk = first;
- do {
- if (tsk->exit_state)
- continue;
- /*
- * Accounting subsystem can call its functions here to
- * fill in relevant parts of struct taskstsats as follows
- *
- * per-task-foo(stats, tsk);
- */
- delayacct_add_tsk(stats, tsk);
-
- stats->nvcsw += tsk->nvcsw;
- stats->nivcsw += tsk->nivcsw;
- } while_each_thread(first, tsk);
+ do
+ if (!tsk->exit_state)
+ /*
+ * This check is racy as a thread could exit just right
+ * now and have its statistics accounted twice.
+ */
+ add_tsk(stats, tsk);
+ while_each_thread(first, tsk);
+
+ if (first->signal->group_exit_code >> 8)
+ stats->ac_exitcode = first->signal->group_exit_code >> 8;
unlock_task_sighand(first, &flags);
rc = 0;
out:
rcu_read_unlock();
-
- stats->version = TASKSTATS_VERSION;
- /*
- * Accounting subsytems can also add calls here to modify
- * fields of taskstats.
- */
return rc;
}
@@ -266,20 +306,17 @@ static void fill_tgid_exit(struct task_s
{
unsigned long flags;
- spin_lock_irqsave(&tsk->sighand->siglock, flags);
- if (!tsk->signal->stats)
- goto ret;
-
- /*
- * Each accounting subsystem calls its functions here to
- * accumalate its per-task stats for tsk, into the per-tgid structure
- *
- * per-task-foo(tsk->signal->stats, tsk);
- */
- delayacct_add_tsk(tsk->signal->stats, tsk);
-ret:
- spin_unlock_irqrestore(&tsk->sighand->siglock, flags);
- return;
+ rcu_read_lock();
+ lock_task_sighand(tsk, &flags);
+
+ /*
+ * The fill_threadgroup() part of the statistics will be added by the
+ * stats requester, i.e. fill_tgid()
+ */
+ add_tsk(tsk->signal->stats, tsk);
+
+ unlock_task_sighand(tsk, &flags);
+ rcu_read_unlock();
}
static int add_del_listener(pid_t pid, cpumask_t *maskp, int isadd)
diff -r ec584ed21efa kernel/tsacct.c
--- a/kernel/tsacct.c Fri Sep 14 14:04:13 2007 -0700
+++ b/kernel/tsacct.c Sat Sep 15 20:22:55 2007 +0200
@@ -22,50 +22,65 @@
#include <linux/acct.h>
#include <linux/jiffies.h>
-/*
- * fill in basic accounting fields
- */
-void bacct_add_tsk(struct taskstats *stats, struct task_struct *tsk)
+static void fill_wall_times(struct taskstats *stats, struct task_struct *task)
{
struct timespec uptime, ts;
s64 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);
+ ts = timespec_sub(uptime, task->start_time);
/* rebase elapsed time to usec */
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_etime = ac_etime;
+ stats->ac_btime = get_seconds() - ts.tv_sec;
+}
+
+/*
+ * fill in basic accounting fields
+ */
+
+void bacct_fill_threadgroup(struct taskstats *stats, struct task_struct *task)
+{
+ BUILD_BUG_ON(TS_COMM_LEN < TASK_COMM_LEN);
+
+ rcu_read_lock();
+ stats->ac_ppid = pid_alive(task) ?
+ rcu_dereference(task->real_parent)->tgid : 0;
+ rcu_read_unlock();
+
+ fill_wall_times(stats, task);
+
+ stats->ac_exitcode = task->exit_code >> 8;
+ stats->ac_nice = task_nice(task);
+ stats->ac_sched = task->policy;
+ stats->ac_uid = task->uid;
+ stats->ac_gid = task->gid;
+ stats->ac_pid = task->pid;
+
+ strncpy(stats->ac_comm, task->comm, sizeof(stats->ac_comm));
+}
+
+void bacct_add_tsk(struct taskstats *stats, struct task_struct *task)
+{
+ if (task->flags & PF_SUPERPRIV)
stats->ac_flag |= ASU;
- if (tsk->flags & PF_DUMPCORE)
+ if (task->flags & PF_DUMPCORE)
stats->ac_flag |= ACORE;
- if (tsk->flags & PF_SIGNALED)
+ if (task->flags & PF_SIGNALED)
stats->ac_flag |= AXSIG;
- stats->ac_nice = task_nice(tsk);
- stats->ac_sched = tsk->policy;
- stats->ac_uid = tsk->uid;
- stats->ac_gid = tsk->gid;
- stats->ac_pid = tsk->pid;
- rcu_read_lock();
- stats->ac_ppid = pid_alive(tsk) ?
- rcu_dereference(tsk->real_parent)->tgid : 0;
- rcu_read_unlock();
- stats->ac_utime = cputime_to_msecs(tsk->utime) * USEC_PER_MSEC;
- stats->ac_stime = cputime_to_msecs(tsk->stime) * USEC_PER_MSEC;
- stats->ac_minflt = tsk->min_flt;
- stats->ac_majflt = tsk->maj_flt;
+ if (thread_group_leader(task) && (task->flags & PF_FORKNOEXEC))
+ /*
+ * Threads are created by do_fork() and don't exec but not in
+ * the AFORK sense, as the latter involves fork(2).
+ */
+ stats->ac_flag |= AFORK;
- strncpy(stats->ac_comm, tsk->comm, sizeof(stats->ac_comm));
+ stats->ac_utime += cputime_to_msecs(task->utime) * USEC_PER_MSEC;
+ stats->ac_stime += cputime_to_msecs(task->stime) * USEC_PER_MSEC;
+ stats->ac_minflt += task->min_flt;
+ stats->ac_majflt += task->maj_flt;
}
@@ -76,32 +91,34 @@ void bacct_add_tsk(struct taskstats *sta
/*
* fill in extended accounting fields
*/
-void xacct_add_tsk(struct taskstats *stats, struct task_struct *p)
+void xacct_fill_threadgroup(struct taskstats *stats, struct task_struct *task)
{
struct mm_struct *mm;
- /* convert pages-jiffies to Mbyte-usec */
- stats->coremem = jiffies_to_usecs(p->acct_rss_mem1) * PAGE_SIZE / MB;
- stats->virtmem = jiffies_to_usecs(p->acct_vm_mem1) * PAGE_SIZE / MB;
- mm = get_task_mm(p);
+ mm = get_task_mm(task);
if (mm) {
/* adjust to KB unit */
stats->hiwater_rss = mm->hiwater_rss * PAGE_SIZE / KB;
- stats->hiwater_vm = mm->hiwater_vm * PAGE_SIZE / KB;
+ stats->hiwater_vm = mm->hiwater_vm * PAGE_SIZE / KB;
mmput(mm);
}
- stats->read_char = p->rchar;
- stats->write_char = p->wchar;
- stats->read_syscalls = p->syscr;
- stats->write_syscalls = p->syscw;
+}
+
+void xacct_add_tsk(struct taskstats *stats, struct task_struct *p)
+{
+ /* convert pages-jiffies to Mbyte-usec */
+ stats->coremem += jiffies_to_usecs(p->acct_rss_mem1) * PAGE_SIZE / MB;
+ stats->virtmem += jiffies_to_usecs(p->acct_vm_mem1) * PAGE_SIZE / MB;
+
+ stats->read_char += p->rchar;
+ stats->write_char += p->wchar;
+ stats->read_syscalls += p->syscr;
+ stats->write_syscalls += p->syscw;
+
#ifdef CONFIG_TASK_IO_ACCOUNTING
- stats->read_bytes = p->ioac.read_bytes;
- stats->write_bytes = p->ioac.write_bytes;
- stats->cancelled_write_bytes = p->ioac.cancelled_write_bytes;
-#else
- stats->read_bytes = 0;
- stats->write_bytes = 0;
- stats->cancelled_write_bytes = 0;
+ stats->read_bytes += p->ioac.read_bytes;
+ stats->write_bytes += p->ioac.write_bytes;
+ stats->cancelled_write_bytes += p->ioac.cancelled_write_bytes;
#endif
}
#undef KB
-
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