[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>

diff --git a/fs/proc/base.c b/fs/proc/base.c
index 1a979ea3b379931973f79c4b70703df3f237c714..7fb37d6f2864859b82cb12062706f462af00ec28 100644 (file)
--- 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 707ac21700d31d26ee85d85734e4c3138853dd70..bcb0ef2aae3d5f54588616102b0d220d1aa63d94 100644 (file)
--- 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 4463735351904f039b1c3239f6161f52ce88ad77..76c8e2dc48dd3833969d2da24b9c7dbdd6bcc306 100644 (file)
--- 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 d57118da73ff04cfecc4b09b689c7bf74191dcc6..80284eb488ced61808dedf0b999af2f55c494d28 100644 (file)
--- 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);