lkml.org 
[lkml]   [2006]   [Aug]   [17]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[PATCH -mm] simplify pid iterators
On top of Eric's recent include/linux/pid.h changes.

I think it is hardly possible to read the current do_each_task_pid().
The new version is much simpler and makes the code smaller.

Only the do_each_task_pid change is tested, the do_each_pid_task isn't.
Eric, could you take a hard look at this patch?

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>

--- 2.6.18-rc3/include/linux/pid.h~ 2006-08-16 20:40:05.000000000 +0400
+++ 2.6.18-rc3/include/linux/pid.h 2006-08-18 00:45:06.000000000 +0400
@@ -99,42 +99,29 @@ static inline pid_t pid_nr(struct pid *p
return nr;
}

-#define pid_next(task, type) \
- ((task)->pids[(type)].node.next)

-#define pid_next_task(task, type) \
- hlist_entry(pid_next(task, type), struct task_struct, \
- pids[(type)].node)
-
-
-/* We could use hlist_for_each_entry_rcu here but it takes more arguments
- * than the do_each_task_pid/while_each_task_pid. So we roll our own
- * to preserve the existing interface.
- */
-#define do_each_task_pid(who, type, task) \
- if ((task = find_task_by_pid_type(type, who))) { \
- prefetch(pid_next(task, type)); \
- do {
-
-#define while_each_task_pid(who, type, task) \
- } while (pid_next(task, type) && ({ \
- task = pid_next_task(task, type); \
- rcu_dereference(task); \
- prefetch(pid_next(task, type)); \
- 1; }) ); \
- }
-
-#define do_each_pid_task(pid, type, task) \
- if ((task = pid_task(pid, type))) { \
- prefetch(pid_next(task, type)); \
- do {
-
-#define while_each_pid_task(pid, type, task) \
- } while (pid_next(task, type) && ({ \
- task = pid_next_task(task, type); \
- rcu_dereference(task); \
- prefetch(pid_next(task, type)); \
- 1; }) ); \
- }
+#define do_each_task_pid(who, type, task) \
+ do { \
+ struct hlist_node *pos___; \
+ struct pid *pid___ = find_pid(who); \
+ if (pid___ != NULL) \
+ hlist_for_each_entry_rcu((task), pos___, \
+ &pid___->tasks[type], pids[type].node) {
+
+#define while_each_task_pid(who, type, task) \
+ } \
+ } while (0)
+
+
+#define do_each_pid_task(pid, type, task) \
+ do { \
+ struct hlist_node *pos___; \
+ if (pid != NULL) \
+ hlist_for_each_entry_rcu((task), pos___, \
+ &pid->tasks[type], pids[type].node) {
+
+#define while_each_pid_task(pid, type, task) \
+ } \
+ } while (0)

#endif /* _LINUX_PID_H */
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2006-08-17 18:55    [from the cache]
©2003-2011 Jasper Spaans. Advertise on this site