lkml.org 
[lkml]   [2005]   [Nov]   [22]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
Subject[Question] I doublt on spin_lock again.
Hi, All.

I come here again.

I have two questions on spin_lock. these are:

1. I found these use spin_lock(&rq->lock) in set_user_nice(), but
not disable interrput ( e.g. when sys_nice() call it ), if the one
timer interrput come before we unlock the spin_lock, Shall
we dead lock here? Since the scheduler_tick() may try to hold the same
lock.

2. I also found some function name in its definition have some
postfix, I show here two classical examples:

static void double_rq_lock(runqueue_t *rq1, runqueue_t *rq2)
__acquires(rq1->lock)
__acquires(rq2->lock)
{ ... }

static void double_rq_unlock(runqueue_t *rq1, runqueue_t *rq2)
__releases(rq1->lock)
__releases(rq2->lock)
{ ... }

In the related header files, they are defined as two preprocess
macroes, are follow:

# define __acquires(x) __attribute__((context(0,1)))
# define __releases(x) __attribute__((context(1,0)))
# define __acquire(x) __context__(1)
# define __release(x) __context__(-1)


I guess they are some extensions of gcc for C language, but I did
not found any information in GCC manual.

Would you like reply these questions? Thank advanced.

-liyu









-
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: 2005-11-23 03:06    [W:0.039 / U:39.348 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site