[RFC PATCH 4/5] fs/proc: Introduce /proc/all/io

Eugene Lubarsky
2020-08-10T14:59:43Z

Returns io info for all visible processes.

The data is the same as /proc/[pid]/io but formatted as a series
of numbers on a single line. A PID column is also prepended.

Signed-off-by: Eugene Lubarsky <elubarsky.linux@gmail.com>
---
fs/proc/base.c | 66 ++++++++++++++++++++++++++++++++++++++++++++------
1 file changed, 59 insertions(+), 7 deletions(-)

diff --git a/fs/proc/base.c b/fs/proc/base.c
index 5982fd43dd21..03d48225b6d1 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -2910,9 +2910,8 @@ static const struct file_operations proc_coredump_filter_operations = {
#endif

#ifdef CONFIG_TASK_IO_ACCOUNTING
-static int do_io_accounting(struct task_struct *task, struct seq_file *m, int whole)
+static int calc_io_accounting(struct task_struct *task, struct task_io_accounting *acct, int whole)
{
- struct task_io_accounting acct = task->ioac;
unsigned long flags;
int result;

@@ -2928,12 +2927,27 @@ static int do_io_accounting(struct task_struct *task, struct seq_file *m, int wh
if (whole && lock_task_sighand(task, &flags)) {
struct task_struct *t = task;

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

unlock_task_sighand(task, &flags);
}
+ result = 0;
+
+out_unlock:
+ mutex_unlock(&task->signal->exec_update_mutex);
+ return result;
+}
+static int do_io_accounting(struct task_struct *task, struct seq_file *m, int whole)
+{
+ struct task_io_accounting acct = task->ioac;
+ int result;
+
+ result = calc_io_accounting(task, &acct, whole);
+ if (result)
+ return result;
+
seq_printf(m,
"rchar: %llu\n"
"wchar: %llu\n"
@@ -2949,10 +2963,7 @@ static int do_io_accounting(struct task_struct *task, struct seq_file *m, int wh
(unsigned long long)acct.read_bytes,
(unsigned long long)acct.write_bytes,
(unsigned long long)acct.cancelled_write_bytes);
- result = 0;

-out_unlock:
- mutex_unlock(&task->signal->exec_update_mutex);
return result;
}

@@ -3896,7 +3907,42 @@ static int proc_all_statm(struct seq_file *m, void *v)
return proc_pid_statm(m, ns, pid, task);
}

+#ifdef CONFIG_TASK_IO_ACCOUNTING
+static int proc_all_io_print_one(struct seq_file *m, struct task_struct *task)
+{
+ struct task_io_accounting acct = task->ioac;
+ int result;

+ result = calc_io_accounting(task, &acct, 1);
+ if (result)
+ return result;
+
+ seq_printf(m,
+ "%llu %llu %llu %llu %llu %llu %llu\n",
+ (unsigned long long)acct.rchar,
+ (unsigned long long)acct.wchar,
+ (unsigned long long)acct.syscr,
+ (unsigned long long)acct.syscw,
+ (unsigned long long)acct.read_bytes,
+ (unsigned long long)acct.write_bytes,
+ (unsigned long long)acct.cancelled_write_bytes);
+
+ return result;
+}
+
+static int proc_all_io(struct seq_file *m, void *v)
+{
+ struct all_iter *iter = (struct all_iter *) v;
+ struct pid_namespace *ns = iter->ns;
+ struct task_struct *task = iter->tgid_iter.task;
+ struct pid *pid = task->thread_pid;
+
+ seq_put_decimal_ull(m, "", pid_nr_ns(pid, ns));
+ seq_puts(m, " ");
+
+ return proc_all_io_print_one(m, task);
+}
+#endif

static int proc_all_status(struct seq_file *m, void *v)
{
@@ -3915,6 +3961,9 @@ static int proc_all_status(struct seq_file *m, void *v)
PROC_ALL_OPS(stat);
PROC_ALL_OPS(statm);
PROC_ALL_OPS(status);
+#ifdef CONFIG_TASK_IO_ACCOUNTING
+ PROC_ALL_OPS(io);
+#endif

#define PROC_ALL_CREATE(NAME) \
do { \
@@ -3932,4 +3981,7 @@ void __init proc_all_init(void)
PROC_ALL_CREATE(stat);
PROC_ALL_CREATE(statm);
PROC_ALL_CREATE(status);
+#ifdef CONFIG_TASK_IO_ACCOUNTING
+ PROC_ALL_CREATE(io);
+#endif
}
--
2.25.1