[PATCH] ifdef ->rchar, ->wchar, ->syscr, ->syscw from task_struct

They are fat: 4x8 bytes in task_struct.
They are uncoditionally updated in every fork, read, write and sendfile.
They are used only if you have some "extended acct fields feature".

And please, please, please, read(2) knows about bytes, not characters,
why it is called "rchar"?

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Jay Lan <jlan@engr.sgi.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 4 insertions, 0 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);