From: Peter Zijlstra <peterz@infradead.org>
To: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>,
tglx@linutronix.de, mingo@kernel.org, bigeasy@linutronix.de,
umgwanakikbuti@gmail.com, paulmck@linux.vnet.ibm.com,
linux-kernel@vger.kernel.org, kmo@daterainc.com
Subject: Re: [PATCH 4/3] rtmutex: Avoid barrier in rt_mutex_handle_deadlock
Date: Tue, 22 Mar 2016 13:20:50 +0100 [thread overview]
Message-ID: <20160322122050.GM6344@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <20160322113221.GA3921@osiris>
On Tue, Mar 22, 2016 at 12:32:21PM +0100, Heiko Carstens wrote:
> On Tue, Mar 22, 2016 at 11:21:53AM +0100, Peter Zijlstra wrote:
> > And s390 does something entirely vile, no idea what.
>
> For the two s390 usages tsk equals current. So it could be easily replaced
> with set_current_state().
Hmm indeed, I only saw tsk = find_task_by_pid_ns() and didn't look
further, but you do indeed have an assertion later that ensures task ==
current.
I still don't get that code though; why would you set the current task
state to UNINTERRUPTIBLE, also set need_resched, but then not call
schedule() at all.
Clearly something magical is going on and its not clear.
next prev parent reply other threads:[~2016-03-22 12:21 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-08 18:20 [PATCH -tip 0/3] locking/rtmutex: Another crack at spin on owner Davidlohr Bueso
2016-03-08 18:20 ` [PATCH 1/3] rtmutex: Delete save_state member of struct rt_mutex Davidlohr Bueso
2016-03-08 18:20 ` [PATCH 2/3] rtmutex: Add rt_mutex_init_waiter helper Davidlohr Bueso
2016-03-14 13:16 ` Peter Zijlstra
2016-03-08 18:20 ` [PATCH 3/3] rtmutex: Reduce top-waiter blocking on a lock Davidlohr Bueso
2016-03-14 13:23 ` Peter Zijlstra
2016-03-08 22:05 ` [PATCH 4/3] rtmutex: Avoid barrier in rt_mutex_handle_deadlock Davidlohr Bueso
2016-03-14 13:40 ` Peter Zijlstra
2016-03-21 18:16 ` Davidlohr Bueso
2016-03-22 10:21 ` Peter Zijlstra
2016-03-22 11:32 ` Heiko Carstens
2016-03-22 12:20 ` Peter Zijlstra [this message]
2016-03-22 13:26 ` Heiko Carstens
2016-03-22 13:55 ` Peter Zijlstra
2016-03-22 14:45 ` Heiko Carstens
2016-03-22 16:41 ` Peter Zijlstra
2016-03-22 21:46 ` Heiko Carstens
2016-03-25 2:30 ` Davidlohr Bueso
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20160322122050.GM6344@twins.programming.kicks-ass.net \
--to=peterz@infradead.org \
--cc=bigeasy@linutronix.de \
--cc=dave@stgolabs.net \
--cc=heiko.carstens@de.ibm.com \
--cc=kmo@daterainc.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@kernel.org \
--cc=paulmck@linux.vnet.ibm.com \
--cc=tglx@linutronix.de \
--cc=umgwanakikbuti@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).