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authorAndrea Righi <righi.andrea@gmail.com>2008-07-26 15:22:27 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-07-26 20:16:47 -0700
commitb2d002dba5a8a4c0c3ec96fd1ff3c9def6bd71a1 (patch)
treea87afab3739039531bdec50aa4f588cdd672bd02 /fs
parent6a9436d0c3cbe8941b1acd5b0736d355295cad98 (diff)
downloadlinux-2.6.34-ux500-b2d002dba5a8a4c0c3ec96fd1ff3c9def6bd71a1.tar.gz
task IO accounting: correctly account threads IO statistics
Oleg Nesterov points out that we should check that the task is still alive before we iterate over the threads. This patch includes a fixup for this. Also simplify do_io_accounting() implementation. Signed-off-by: Andrea Righi <righi.andrea@gmail.com> Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs')
-rw-r--r--fs/proc/base.c56
1 files changed, 22 insertions, 34 deletions
diff --git a/fs/proc/base.c b/fs/proc/base.c
index 81bce6791bf..d744aa3c9f7 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -2406,35 +2406,18 @@ static int do_io_accounting(struct task_struct *task, char *buffer, int whole)
u64 rchar, wchar, syscr, syscw;
struct task_io_accounting ioac;
- if (!whole) {
- rchar = task->rchar;
- wchar = task->wchar;
- syscr = task->syscr;
- syscw = task->syscw;
- memcpy(&ioac, &task->ioac, sizeof(ioac));
- } else {
- unsigned long flags;
- struct task_struct *t = task;
- rchar = wchar = syscr = syscw = 0;
- memset(&ioac, 0, sizeof(ioac));
+ rchar = task->rchar;
+ wchar = task->wchar;
+ syscr = task->syscr;
+ syscw = task->syscw;
+ memcpy(&ioac, &task->ioac, sizeof(ioac));
- rcu_read_lock();
- do {
- rchar += t->rchar;
- wchar += t->wchar;
- syscr += t->syscr;
- syscw += t->syscw;
-
- ioac.read_bytes += t->ioac.read_bytes;
- ioac.write_bytes += t->ioac.write_bytes;
- ioac.cancelled_write_bytes +=
- t->ioac.cancelled_write_bytes;
- t = next_thread(t);
- } while (t != task);
- rcu_read_unlock();
+ if (whole) {
+ unsigned long flags;
if (lock_task_sighand(task, &flags)) {
struct signal_struct *sig = task->signal;
+ struct task_struct *t = task;
rchar += sig->rchar;
wchar += sig->wchar;
@@ -2445,11 +2428,20 @@ static int do_io_accounting(struct task_struct *task, char *buffer, int whole)
ioac.write_bytes += sig->ioac.write_bytes;
ioac.cancelled_write_bytes +=
sig->ioac.cancelled_write_bytes;
-
+ while_each_thread(task, t) {
+ rchar += t->rchar;
+ wchar += t->wchar;
+ syscr += t->syscr;
+ syscw += t->syscw;
+
+ ioac.read_bytes += t->ioac.read_bytes;
+ ioac.write_bytes += t->ioac.write_bytes;
+ ioac.cancelled_write_bytes +=
+ t->ioac.cancelled_write_bytes;
+ }
unlock_task_sighand(task, &flags);
}
}
-
return sprintf(buffer,
"rchar: %llu\n"
"wchar: %llu\n"
@@ -2458,13 +2450,9 @@ static int do_io_accounting(struct task_struct *task, char *buffer, int whole)
"read_bytes: %llu\n"
"write_bytes: %llu\n"
"cancelled_write_bytes: %llu\n",
- (unsigned long long)rchar,
- (unsigned long long)wchar,
- (unsigned long long)syscr,
- (unsigned long long)syscw,
- (unsigned long long)ioac.read_bytes,
- (unsigned long long)ioac.write_bytes,
- (unsigned long long)ioac.cancelled_write_bytes);
+ rchar, wchar, syscr, syscw,
+ ioac.read_bytes, ioac.write_bytes,
+ ioac.cancelled_write_bytes);
}
static int proc_tid_io_accounting(struct task_struct *task, char *buffer)