lkml.org 
[lkml]   [2003]   [Mar]   [4]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: Inconsistency in changing the state of task ??
From
Date
On Tue, 2003-03-04 at 03:36, prash_t@softhome.net wrote:

> while browsing through fs/select.c file of 2.4.19, I came across two
> DIFFERENT ways of changing the state of the current task in do_select():
>
> set_current_state = TASK_INTERRUPTIBLE;
> AND current->state = TASK_RUNNING;
>
> I am curious to know if the second line of code doesn't cause any problem in
> SMP systems. I also see the same situation in do_poll().

You normally want to use set_current_state(), which is a nice
abstraction and safe for SMP.

Sometimes it is safe to use __set_current_state(), which does not
provide a memory barrier.

The above open-coded line can be changed to
__set_current_state(TASK_RUNNING).

Robert Love

-
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: 2005-03-22 13:33    [W:0.032 / U:0.988 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site