4 files changed, 58 insertions, 12 deletions

diff --git a/fs/proc/base.c b/fs/proc/base.c
index 1a979ea3b379..7fb37d6f2864 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -1810,17 +1810,21 @@ static int proc_base_fill_cache(struct file *filp, void *dirent, filldir_t filld
 static int proc_pid_io_accounting(struct task_struct *task, char *buffer)
 {
         return sprintf(buffer,
+#ifdef CONFIG_TASK_XACCT
                         "rchar: %llu\n"
                         "wchar: %llu\n"
                         "syscr: %llu\n"
                         "syscw: %llu\n"
+#endif
                         "read_bytes: %llu\n"
                         "write_bytes: %llu\n"
                         "cancelled_write_bytes: %llu\n",
+#ifdef CONFIG_TASK_XACCT
                         (unsigned long long)task->rchar,
                         (unsigned long long)task->wchar,
                         (unsigned long long)task->syscr,
                         (unsigned long long)task->syscw,
+#endif
                         (unsigned long long)task->ioac.read_bytes,
                         (unsigned long long)task->ioac.write_bytes,
                         (unsigned long long)task->ioac.cancelled_write_bytes);
diff --git a/fs/read_write.c b/fs/read_write.c
index 707ac21700d3..bcb0ef2aae3d 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -274,9 +274,9 @@ ssize_t vfs_read(struct file *file, char __user *buf, size_t count, loff_t *pos)
                                 ret = do_sync_read(file, buf, count, pos);
                         if (ret > 0) {
                                 fsnotify_access(file->f_path.dentry);
-                                current->rchar += ret;
+                                add_rchar(current, ret);
                         }
-                        current->syscr++;
+                        inc_syscr(current);
                 }
         }
 
@@ -332,9 +332,9 @@ ssize_t vfs_write(struct file *file, const char __user *buf, size_t count, loff_
                                 ret = do_sync_write(file, buf, count, pos);
                         if (ret > 0) {
                                 fsnotify_modify(file->f_path.dentry);
-                                current->wchar += ret;
+                                add_wchar(current, ret);
                         }
-                        current->syscw++;
+                        inc_syscw(current);
                 }
         }
 
@@ -675,8 +675,8 @@ sys_readv(unsigned long fd, const struct iovec __user *vec, unsigned long vlen)
         }
 
         if (ret > 0)
-                current->rchar += ret;
-        current->syscr++;
+                add_rchar(current, ret);
+        inc_syscr(current);
         return ret;
 }
 
@@ -696,8 +696,8 @@ sys_writev(unsigned long fd, const struct iovec __user *vec, unsigned long vlen)
         }
 
         if (ret > 0)
-                current->wchar += ret;
-        current->syscw++;
+                add_wchar(current, ret);
+        inc_syscw(current);
         return ret;
 }
 
@@ -779,12 +779,12 @@ static ssize_t do_sendfile(int out_fd, int in_fd, loff_t *ppos,
         retval = in_file->f_op->sendfile(in_file, ppos, count, file_send_actor, out_file);
 
         if (retval > 0) {
-                current->rchar += retval;
-                current->wchar += retval;
+                add_rchar(current, retval);
+                add_wchar(current, retval);
         }
-        current->syscr++;
-        current->syscw++;
 
+        inc_syscr(current);
+        inc_syscw(current);
         if (*ppos > max)
                 retval = -EOVERFLOW;
 
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 446373535190..76c8e2dc48dd 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1013,8 +1013,10 @@ struct task_struct {
  * to a stack based synchronous wait) if its doing sync IO.
  */
         wait_queue_t *io_wait;
+#ifdef CONFIG_TASK_XACCT
 /* i/o counters(bytes read/written, #syscalls */
         u64 rchar, wchar, syscr, syscw;
+#endif
         struct task_io_accounting ioac;
 #if defined(CONFIG_TASK_XACCT)
         u64 acct_rss_mem1;      /* accumulated rss usage */
@@ -1649,6 +1651,44 @@ extern int sched_create_sysfs_power_savings_entries(struct sysdev_class *cls);
 
 extern void normalize_rt_tasks(void);
 
+#ifdef CONFIG_TASK_XACCT
+static inline void add_rchar(struct task_struct *tsk, ssize_t amt)
+{
+        tsk->rchar += amt;
+}
+
+static inline void add_wchar(struct task_struct *tsk, ssize_t amt)
+{
+        tsk->wchar += amt;
+}
+
+static inline void inc_syscr(struct task_struct *tsk)
+{
+        tsk->syscr++;
+}
+
+static inline void inc_syscw(struct task_struct *tsk)
+{
+        tsk->syscw++;
+}
+#else
+static inline void add_rchar(struct task_struct *tsk, ssize_t amt)
+{
+}
+
+static inline void add_wchar(struct task_struct *tsk, ssize_t amt)
+{
+}
+
+static inline void inc_syscr(struct task_struct *tsk)
+{
+}
+
+static inline void inc_syscw(struct task_struct *tsk)
+{
+}
+#endif
+
 #endif /* __KERNEL__ */
 
 #endif
diff --git a/kernel/fork.c b/kernel/fork.c
index d57118da73ff..80284eb488ce 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1038,10 +1038,12 @@ static struct task_struct *copy_process(unsigned long clone_flags,
         p->utime = cputime_zero;
         p->stime = cputime_zero;
         p->sched_time = 0;
+#ifdef CONFIG_TASK_XACCT
         p->rchar = 0;           /* I/O counter: bytes read */
         p->wchar = 0;           /* I/O counter: bytes written */
         p->syscr = 0;           /* I/O counter: read syscalls */
         p->syscw = 0;           /* I/O counter: write syscalls */
+#endif
         task_io_accounting_init(p);
         acct_clear_integrals(p);