From: Nick Piggin <nickpiggin@yahoo.com.au>
To: Andrew Morton <akpm@osdl.org>
Cc: Ingo Molnar <mingo@elte.hu>,
paulmck@us.ibm.com, linux-kernel@vger.kernel.org,
oleg@tv-sign.ru, dipankar@in.ibm.com, suzannew@cs.pdx.edu
Subject: Re: [PATCH] Fixes for RCU handling of task_struct
Date: Mon, 07 Nov 2005 12:12:25 +1100 [thread overview]
Message-ID: <436EA9F9.4020809@yahoo.com.au> (raw)
In-Reply-To: <20051106134945.0e10cb60.akpm@osdl.org>
Andrew Morton wrote:
>>+static inline int get_task_struct_rcu(struct task_struct *t)
>>+{
>>+ int oldusage;
>>+
>>+ do {
>>+ oldusage = atomic_read(&t->usage);
>>+ if (oldusage == 0) {
>>+ return 0;
>>+ }
>>+ } while (cmpxchg(&t->usage.counter,
>>+ oldusage, oldusage + 1) != oldusage);
>>+ return 1;
>>+}
>
>
> arm (at least) does not implement cmpxchg.
>
Yes, and using atomic_t.counter in generic code is ugly, albeit
compatible with all current implementations.
> I think Nick is working on patches which implement cmpxchg on all
> architectures?
>
Yes, it is basically ready to go.
--
SUSE Labs, Novell Inc.
Send instant messages to your online friends http://au.messenger.yahoo.com
next prev parent reply other threads:[~2005-11-07 1:10 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-10-31 2:05 [PATCH] Fixes for RCU handling of task_struct Paul E. McKenney
2005-10-31 14:04 ` Ingo Molnar
2005-10-31 14:08 ` Ingo Molnar
2005-11-01 4:51 ` Andrew Morton
2005-11-03 19:09 ` Paul E. McKenney
2005-11-04 17:41 ` Oleg Nesterov
2005-11-04 20:08 ` Paul E. McKenney
2005-11-05 16:32 ` Oleg Nesterov
2005-11-05 23:20 ` Paul E. McKenney
2005-11-06 12:01 ` Oleg Nesterov
2005-11-06 22:59 ` Paul E. McKenney
2005-11-07 13:17 ` Oleg Nesterov
2005-11-07 18:28 ` Oleg Nesterov
2005-11-06 21:49 ` Andrew Morton
2005-11-06 22:43 ` Paul E. McKenney
2005-11-07 1:12 ` Nick Piggin [this message]
2005-11-07 4:58 ` Paul E. McKenney
2005-11-07 5:51 ` Nick Piggin
2005-11-07 18:10 ` Paul E. McKenney
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