From: Andrew Morton <[EMAIL PROTECTED]>
Add a simple /proc/pid/io to show the IO accounting fields.
Maybe this shouldn't be merged in mainline - the preferred reporting channel
is taskstats. But given the poor state of our userspace support for
taskstats, this is useful for developer-testing, at least. And it improves
the changes that the procps developers will wire it up into top(1). Opinions
are sought.
The patch also wires up the existing IO-accounting fields.
It's a bit racy on 32-bit machines: if process A reads process B's
/proc/pid/io while process B is updating one of those 64-bit counters, process
A could see an intermediate result.
Cc: Jay Lan <[EMAIL PROTECTED]>
Cc: Shailabh Nagar <[EMAIL PROTECTED]>
Cc: Balbir Singh <[EMAIL PROTECTED]>
Cc: Chris Sturtivant <[EMAIL PROTECTED]>
Cc: Tony Ernst <[EMAIL PROTECTED]>
Cc: Guillaume Thouvenin <[EMAIL PROTECTED]>
Cc: David Wright <[EMAIL PROTECTED]>
Signed-off-by: Andrew Morton <[EMAIL PROTECTED]>
---
fs/proc/base.c | 24 ++++++++++++++++++++++++
1 file changed, 24 insertions(+)
diff -puN fs/proc/base.c~io-accounting-report-in-procfs fs/proc/base.c
--- a/fs/proc/base.c~io-accounting-report-in-procfs
+++ a/fs/proc/base.c
@@ -1804,6 +1804,27 @@ static int proc_base_fill_cache(struct f
proc_base_instantiate, task, p);
}
+#ifdef CONFIG_TASK_IO_ACCOUNTING
+static int proc_pid_io_accounting(struct task_struct *task, char *buffer)
+{
+ return sprintf(buffer,
+ "rchar: %llu\n"
+ "wchar: %llu\n"
+ "syscr: %llu\n"
+ "syscw: %llu\n"
+ "read_bytes: %llu\n"
+ "write_bytes: %llu\n"
+ "cancelled_write_bytes: %llu\n",
+ (unsigned long long)task->rchar,
+ (unsigned long long)task->wchar,
+ (unsigned long long)task->syscr,
+ (unsigned long long)task->syscw,
+ (unsigned long long)task->ioac.read_bytes,
+ (unsigned long long)task->ioac.write_bytes,
+ (unsigned long long)task->ioac.cancelled_write_bytes);
+}
+#endif
+
/*
* Thread groups
*/
@@ -1855,6 +1876,9 @@ static struct pid_entry tgid_base_stuff[
#ifdef CONFIG_FAULT_INJECTION
REG("make-it-fail", S_IRUGO|S_IWUSR, fault_inject),
#endif
+#ifdef CONFIG_TASK_IO_ACCOUNTING
+ INF("io", S_IRUGO, pid_io_accounting),
+#endif
};
static int proc_tgid_base_readdir(struct file * filp,
_
-
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