From: Mike Galbraith <umgwanakikbuti@gmail.com>
To: Christoph Lameter <cl@linux.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: fast path cycle muncher (vmstat: make vmstat_updater deferrable again and shut down on idle)
Date: Sun, 24 Jan 2016 06:36:26 +0100 [thread overview]
Message-ID: <1453613786.4720.8.camel@gmail.com> (raw)
In-Reply-To: <alpine.DEB.2.20.1601232144410.3230@east.gentwo.org>
On Sat, 2016-01-23 at 21:46 -0600, Christoph Lameter wrote:
> On Sun, 24 Jan 2016, Mike Galbraith wrote:
>
> > By switching cross-core, I'm referring to scheduling of communicating
> > tasks.
>
> ??? Its cancelling a work request. That is a "communicating task"?
No no no, pipe-test is two tasks playing ping-pong via a pipe. They
are about as synchronous as it gets, so each task goes idle at high
frequency. Idle is fastpath.
> > Here's the sleeping lock for -rt:
> >
> > [ 2.279582] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.5.0-rt3 #7
> > [ 2.280444] Hardware name: MEDION MS-7848/MS-7848, BIOS M7848W08.20C 09/23/2013
> > [ 2.281316] ffff88040b00d640 ffff88040b01fe10 ffffffff812d20e2 0000000000000000
> > [ 2.282202] ffff88040b01fe30 ffffffff81081095 ffff88041ec4cee0 ffff88041ec501e0
> > [ 2.283073] ffff88040b01fe48 ffffffff815ff910 ffff88041ec4cee0 ffff88040b01fe88
> > [ 2.283941] Call Trace:
> > [ 2.284797] [] dump_stack+0x49/0x67
> > [ 2.285658] [] ___might_sleep+0xf5/0x180
> > [ 2.286521] [] rt_spin_lock+0x20/0x50
> > [ 2.287382] [] try_to_grab_pending+0x69/0x240
> > [ 2.288239] [] cancel_delayed_work+0x26/0xe0
>
> OMG cancelling a work request causes a sleeping lock to be taken?
Yup. In -rt, spinlocks that are not raw are transformed into rtmutex.
-Mike
next prev parent reply other threads:[~2016-01-24 5:37 UTC|newest]
Thread overview: 114+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-12-19 0:33 mm, vmstat: kernel BUG at mm/vmstat.c:1408! Sasha Levin
2015-12-19 0:33 ` Sasha Levin
2015-12-21 13:08 ` Christoph Lameter
2015-12-21 13:08 ` Christoph Lameter
2015-12-21 20:28 ` Sasha Levin
2015-12-21 20:28 ` Sasha Levin
2015-12-21 21:07 ` Sasha Levin
2015-12-21 21:07 ` Sasha Levin
2015-12-21 21:14 ` Christoph Lameter
2015-12-21 21:14 ` Christoph Lameter
2015-12-22 17:21 ` Christoph Lameter
2015-12-22 17:21 ` Christoph Lameter
2015-12-24 20:14 ` Sasha Levin
2015-12-29 17:01 ` Christoph Lameter
2015-12-29 17:01 ` Christoph Lameter
2015-12-29 17:18 ` Christoph Lameter
2015-12-29 17:18 ` Christoph Lameter
2016-01-04 18:05 ` Christoph Lameter
2016-01-04 18:05 ` Christoph Lameter
2016-01-04 18:46 ` Sasha Levin
2016-01-04 18:46 ` Sasha Levin
2016-01-12 11:31 ` Shiraz Hashim
2016-01-12 11:31 ` Shiraz Hashim
2016-01-12 12:23 ` Christoph Lameter
2016-01-12 12:23 ` Christoph Lameter
2016-01-12 12:27 ` Shiraz Hashim
2016-01-12 12:27 ` Shiraz Hashim
2016-01-13 11:36 ` Shiraz Hashim
2016-01-13 11:36 ` Shiraz Hashim
2016-01-13 12:32 ` Shiraz Hashim
2016-01-13 12:32 ` Shiraz Hashim
2016-01-14 21:06 ` Sasha Levin
2016-01-14 21:06 ` Sasha Levin
2016-01-20 14:37 ` Michal Hocko
2016-01-20 14:37 ` Michal Hocko
2016-01-20 14:56 ` Sasha Levin
2016-01-20 14:56 ` Sasha Levin
2016-01-20 15:10 ` Michal Hocko
2016-01-20 15:10 ` Michal Hocko
2016-01-20 15:20 ` Christoph Lameter
2016-01-20 15:20 ` Christoph Lameter
2016-01-20 15:49 ` Sasha Levin
2016-01-20 15:49 ` Sasha Levin
2016-01-20 15:55 ` Christoph Lameter
2016-01-20 15:55 ` Christoph Lameter
2016-01-20 21:28 ` Michal Hocko
2016-01-20 21:28 ` Michal Hocko
2016-01-20 21:57 ` Christoph Lameter
2016-01-20 21:57 ` Christoph Lameter
2016-01-21 8:24 ` Michal Hocko
2016-01-21 8:24 ` Michal Hocko
2016-01-21 15:45 ` Christoph Lameter
2016-01-21 15:45 ` Christoph Lameter
2016-01-21 16:51 ` Michal Hocko
2016-01-21 16:51 ` Michal Hocko
2016-01-21 17:38 ` Christoph Lameter
2016-01-21 17:38 ` Christoph Lameter
2016-01-22 11:00 ` Shiraz Hashim
2016-01-22 11:00 ` Shiraz Hashim
2016-01-22 14:04 ` Michal Hocko
2016-01-22 14:04 ` Michal Hocko
2016-01-22 16:07 ` Christoph Lameter
2016-01-22 16:07 ` Christoph Lameter
2016-01-22 16:12 ` Michal Hocko
2016-01-22 16:12 ` Michal Hocko
2016-01-22 16:46 ` Christoph Lameter
2016-01-22 16:46 ` Christoph Lameter
2016-01-22 17:12 ` Michal Hocko
2016-01-22 17:12 ` Michal Hocko
2016-01-23 16:21 ` fast path cycle muncher (vmstat: make vmstat_updater deferrable again and shut down on idle) Mike Galbraith
2016-01-24 0:33 ` Christoph Lameter
2016-01-24 2:46 ` Mike Galbraith
2016-01-24 3:46 ` Christoph Lameter
2016-01-24 5:36 ` Mike Galbraith [this message]
2016-01-25 17:42 ` Michal Hocko
2016-01-25 18:02 ` Christoph Lameter
2016-01-25 20:13 ` Michal Hocko
2016-01-26 16:25 ` Christoph Lameter
2016-01-26 18:31 ` Mike Galbraith
2016-01-26 18:34 ` Christoph Lameter
2016-01-26 18:45 ` Mike Galbraith
2016-01-26 19:20 ` Christoph Lameter
2016-01-27 3:12 ` Mike Galbraith
2016-01-27 4:15 ` Mike Galbraith
2016-01-27 16:28 ` Christoph Lameter
2016-01-28 15:36 ` Frederic Weisbecker
2016-01-28 16:42 ` Christoph Lameter
2016-01-26 2:14 ` Mike Galbraith
2016-01-26 2:25 ` Mike Galbraith
2016-01-26 16:26 ` Christoph Lameter
2016-01-26 17:39 ` Mike Galbraith
2016-01-26 18:19 ` Christoph Lameter
2016-01-26 16:26 ` Christoph Lameter
2016-01-26 17:08 ` Mike Galbraith
2016-01-26 18:22 ` Christoph Lameter
2016-01-26 19:09 ` Mike Galbraith
2016-01-26 19:22 ` Christoph Lameter
2016-01-27 16:48 ` [PATCH] mm, vmstat: make quiet_vmstat lighter (was: Re: fast path cycle muncher (vmstat: make vmstat_updater deferrable) " Michal Hocko
2016-01-27 17:03 ` Mike Galbraith
2016-01-27 18:26 ` Christoph Lameter
2016-01-28 15:21 ` Michal Hocko
2016-01-28 16:40 ` Christoph Lameter
2016-01-28 16:53 ` Michal Hocko
2016-01-28 17:05 ` Christoph Lameter
2016-01-28 15:31 ` Michal Hocko
2016-01-28 15:37 ` [PATCH] vmstat: make vmstat_update deferrable (was: Re: [PATCH] mm, vmstat: make quiet_vmstat lighter) " Michal Hocko
2016-01-28 16:48 ` Christoph Lameter
2016-01-28 16:42 ` [PATCH] mm, vmstat: make quiet_vmstat lighter (was: Re: fast " Christoph Lameter
2016-01-24 16:57 ` mm, vmstat: kernel BUG at mm/vmstat.c:1408! Linus Torvalds
2016-01-24 16:57 ` Linus Torvalds
2016-01-20 15:14 ` Christoph Lameter
2016-01-20 15:14 ` Christoph Lameter
2016-01-20 15:20 ` Michal Hocko
2016-01-20 15:20 ` Michal Hocko
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=1453613786.4720.8.camel@gmail.com \
--to=umgwanakikbuti@gmail.com \
--cc=cl@linux.com \
--cc=linux-kernel@vger.kernel.org \
--cc=peterz@infradead.org \
/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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.