From: Dave Hansen <dave@linux.vnet.ibm.com>
To: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: David Rientjes <rientjes@google.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Johannes Weiner <hannes@cmpxchg.org>,
Michal Nazarewicz <mina86@mina86.com>,
Andrew Morton <akpm@linux-foundation.org>,
John Stultz <johnstul@us.ibm.com>
Subject: Re: [PATCH 1/2] break out page allocation warning code
Date: Tue, 19 Apr 2011 19:46:02 -0700 [thread overview]
Message-ID: <1303267562.5076.1004.camel@nimitz> (raw)
In-Reply-To: <20110420112006.461A.A69D9226@jp.fujitsu.com>
On Wed, 2011-04-20 at 11:19 +0900, KOSAKI Motohiro wrote:
> > + memcpy(tmp_comm, tsk->comm_buf, TASK_COMM_LEN);
> > + tsk->comm = tmp;
> > /*
> > - * Threads may access current->comm without holding
> > - * the task lock, so write the string carefully.
> > - * Readers without a lock may see incomplete new
> > - * names but are safe from non-terminating string reads.
> > + * Make sure no one is still looking at tsk->comm_buf
> > */
> > - memset(tsk->comm, 0, TASK_COMM_LEN);
> > - wmb();
> > - strlcpy(tsk->comm, buf, sizeof(tsk->comm));
> > + synchronize_rcu();
>
> The doc says,
>
> /**
> * synchronize_rcu - wait until a grace period has elapsed.
Yeah, yeah... see "completely untested". :)
I'll see if dropping the locks or something else equally hackish can
help.
-- Dave
WARNING: multiple messages have this Message-ID (diff)
From: Dave Hansen <dave@linux.vnet.ibm.com>
To: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: David Rientjes <rientjes@google.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Johannes Weiner <hannes@cmpxchg.org>,
Michal Nazarewicz <mina86@mina86.com>,
Andrew Morton <akpm@linux-foundation.org>,
John Stultz <johnstul@us.ibm.com>
Subject: Re: [PATCH 1/2] break out page allocation warning code
Date: Tue, 19 Apr 2011 19:46:02 -0700 [thread overview]
Message-ID: <1303267562.5076.1004.camel@nimitz> (raw)
In-Reply-To: <20110420112006.461A.A69D9226@jp.fujitsu.com>
On Wed, 2011-04-20 at 11:19 +0900, KOSAKI Motohiro wrote:
> > + memcpy(tmp_comm, tsk->comm_buf, TASK_COMM_LEN);
> > + tsk->comm = tmp;
> > /*
> > - * Threads may access current->comm without holding
> > - * the task lock, so write the string carefully.
> > - * Readers without a lock may see incomplete new
> > - * names but are safe from non-terminating string reads.
> > + * Make sure no one is still looking at tsk->comm_buf
> > */
> > - memset(tsk->comm, 0, TASK_COMM_LEN);
> > - wmb();
> > - strlcpy(tsk->comm, buf, sizeof(tsk->comm));
> > + synchronize_rcu();
>
> The doc says,
>
> /**
> * synchronize_rcu - wait until a grace period has elapsed.
Yeah, yeah... see "completely untested". :)
I'll see if dropping the locks or something else equally hackish can
help.
-- Dave
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next prev parent reply other threads:[~2011-04-20 2:46 UTC|newest]
Thread overview: 79+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-04-15 17:04 [PATCH 1/2] break out page allocation warning code Dave Hansen
2011-04-15 17:04 ` Dave Hansen
2011-04-15 17:04 ` [PATCH 2/2] print vmalloc() state after allocation failures Dave Hansen
2011-04-15 17:04 ` Dave Hansen
2011-04-15 17:20 ` Michal Nazarewicz
2011-04-15 17:20 ` Michal Nazarewicz
2011-04-15 17:44 ` Dave Hansen
2011-04-15 17:44 ` Dave Hansen
2011-04-17 0:03 ` David Rientjes
2011-04-17 0:03 ` David Rientjes
2011-04-18 15:21 ` Dave Hansen
2011-04-18 15:21 ` Dave Hansen
2011-04-17 0:02 ` [PATCH 1/2] break out page allocation warning code David Rientjes
2011-04-17 0:02 ` David Rientjes
2011-04-18 15:10 ` Dave Hansen
2011-04-18 15:10 ` Dave Hansen
2011-04-18 20:25 ` David Rientjes
2011-04-18 20:25 ` David Rientjes
2011-04-18 20:57 ` Dave Hansen
2011-04-18 20:57 ` Dave Hansen
2011-04-19 21:23 ` David Rientjes
2011-04-19 21:23 ` David Rientjes
2011-04-18 21:03 ` Dave Hansen
2011-04-18 21:03 ` Dave Hansen
2011-04-18 21:22 ` Dave Hansen
2011-04-18 21:22 ` Dave Hansen
2011-04-19 0:44 ` KOSAKI Motohiro
2011-04-19 0:44 ` KOSAKI Motohiro
2011-04-19 21:21 ` David Rientjes
2011-04-19 21:21 ` David Rientjes
2011-04-20 0:39 ` KOSAKI Motohiro
2011-04-20 0:39 ` KOSAKI Motohiro
2011-04-20 20:24 ` David Rientjes
2011-04-20 20:24 ` David Rientjes
2011-04-20 20:34 ` john stultz
2011-04-20 20:34 ` john stultz
2011-04-21 1:29 ` KOSAKI Motohiro
2011-04-21 1:29 ` KOSAKI Motohiro
2011-04-25 4:21 ` KOSAKI Motohiro
2011-04-25 4:21 ` KOSAKI Motohiro
2011-04-26 19:27 ` john stultz
2011-04-26 19:27 ` john stultz
2011-04-27 23:51 ` David Rientjes
2011-04-27 23:51 ` David Rientjes
2011-04-28 0:32 ` john stultz
2011-04-28 0:32 ` john stultz
2011-04-28 1:29 ` john stultz
2011-04-28 1:29 ` john stultz
2011-04-28 22:48 ` David Rientjes
2011-04-28 22:48 ` David Rientjes
2011-04-28 23:48 ` john stultz
2011-04-28 23:48 ` john stultz
2011-04-29 0:04 ` john stultz
2011-04-29 0:04 ` john stultz
2011-04-26 21:25 ` john stultz
2011-04-26 21:25 ` john stultz
2011-04-28 3:05 ` KOSAKI Motohiro
2011-04-28 3:05 ` KOSAKI Motohiro
2011-04-20 1:41 ` Dave Hansen
2011-04-20 1:41 ` Dave Hansen
2011-04-20 1:50 ` KOSAKI Motohiro
2011-04-20 1:50 ` KOSAKI Motohiro
2011-04-20 2:19 ` KOSAKI Motohiro
2011-04-20 2:19 ` KOSAKI Motohiro
2011-04-20 2:46 ` Dave Hansen [this message]
2011-04-20 2:46 ` Dave Hansen
-- strict thread matches above, loose matches on Subject: below --
2011-04-19 16:21 Dave Hansen
2011-04-19 16:21 ` Dave Hansen
2011-04-08 20:22 Dave Hansen
2011-04-08 20:22 ` Dave Hansen
2011-04-08 20:37 ` David Rientjes
2011-04-08 20:37 ` David Rientjes
2011-04-08 20:43 ` Dave Hansen
2011-04-08 20:43 ` Dave Hansen
2011-04-08 20:54 ` Michał Nazarewicz
2011-04-08 21:02 ` Dave Hansen
2011-04-08 21:02 ` Dave Hansen
2011-04-11 10:20 ` Michal Nazarewicz
2011-04-11 10:20 ` Michal Nazarewicz
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