From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: Michael Ellerman <mpe@ellerman.id.au>
Cc: Peter Zijlstra <peterz@infradead.org>,
Heiko Carstens <heiko.carstens@de.ibm.com>,
Tiejun Chen <tiejun.chen@windriver.com>,
Paul Mackerras <paulus@samba.org>,
Daniel Walter <dwalter@google.com>,
Ingo Molnar <mingo@kernel.org>,
"open list:S390" <linux-s390@vger.kernel.org>,
Vincent Guittot <vincent.guittot@linaro.org>,
Christian Borntraeger <borntraeger@de.ibm.com>,
Jens Freimann <jfrei@linux.vnet.ibm.com>,
Pranith Kumar <bobby.prani@gmail.com>,
Josh Triplett <josh@joshtriplett.org>,
Steven Rostedt <rostedt@goodmis.org>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Anton Blanchard <anton@samba.org>,
Scott Wood <scottwood@freescale.com>,
Lai Jiangshan <laijs@cn.fujitsu.com>,
Li Zhong <zhong@linux.vnet.ibm.com>,
Nishanth Aravamudan <nacc@linux.vnet.ibm.com>,
open list <linux-kernel@vger.kernel.org>,
"Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>,
Martin Schwidefsky <schwidefsky@de.ibm.com>,
"supporter:S390" <linux390@de.ibm.com>,
"open list:LINUX FOR POWERPC..." <linuxppc-dev@lists.ozlabs.org>
Subject: Re: [PATCH v2] srcu: Isolate srcu sections using CONFIG_SRCU
Date: Sun, 4 Jan 2015 08:14:16 -0800 [thread overview]
Message-ID: <20150104161416.GA5280@linux.vnet.ibm.com> (raw)
In-Reply-To: <1420364152.26772.0.camel@ellerman.id.au>
On Sun, Jan 04, 2015 at 08:35:52PM +1100, Michael Ellerman wrote:
> On Tue, 2014-12-30 at 13:54 -0500, Pranith Kumar wrote:
> > On Tue, Dec 30, 2014 at 1:50 PM, Peter Zijlstra <peterz@infradead.org> wrote:
> > > On Tue, Dec 30, 2014 at 12:46:22AM -0500, Pranith Kumar wrote:
> > >> Isolate the SRCU functions and data structures within CONFIG_SRCU so that there
> > >> is a compile time failure if srcu is used when not enabled. This was decided to
> > >> be better than waiting until link time for a failure to occur.
> > >
> > > Why?
> >
> > This is part of the kernel tinification efforts. The first patch was
> > posted here: https://lkml.org/lkml/2014/12/4/848. This patch enables a
> > compile time failure instead of a link time failure.
>
> The punch line was:
>
> "so the savings are about ~2000 bytes."
>
> Which is utterly not worth the effort IMO. There have got to be more attractive
> targets for tinification than this.
There probably are. But if the tinification effort is to come anywhere
near reaching its goals, it is going to need 2000-byte savings, especially
on the small systems that are this effort's main target.
That said, Peter's suggestion of falling back to the link-time diagnostic
does simplify things a bit, and might be a good approach.
Thanx, Paul
WARNING: multiple messages have this Message-ID (diff)
From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: Michael Ellerman <mpe@ellerman.id.au>
Cc: Pranith Kumar <bobby.prani@gmail.com>,
Peter Zijlstra <peterz@infradead.org>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
Martin Schwidefsky <schwidefsky@de.ibm.com>,
Heiko Carstens <heiko.carstens@de.ibm.com>,
"supporter:S390" <linux390@de.ibm.com>,
Lai Jiangshan <laijs@cn.fujitsu.com>,
Josh Triplett <josh@joshtriplett.org>,
Steven Rostedt <rostedt@goodmis.org>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Scott Wood <scottwood@freescale.com>,
Anton Blanchard <anton@samba.org>,
Daniel Walter <dwalter@google.com>,
Tiejun Chen <tiejun.chen@windriver.com>,
Nishanth Aravamudan <nacc@linux.vnet.ibm.com>,
Ingo Molnar <mingo@kernel.org>,
"Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>,
Vincent Guittot <vincent.guittot@linaro.org>,
Li Zhong <zhong@linux.vnet.ibm.com>,
Christian Borntraeger <borntraeger@de.ibm.com>,
Jens Freimann <jfrei@linux.vnet.ibm.com>,
"open list:LINUX FOR POWERPC..." <linuxppc-dev@lists.ozlabs.org>,
open list <linux-kernel@vger.kernel.org>,
"open list:S390" <linux-s390@vger.kernel.org>
Subject: Re: [PATCH v2] srcu: Isolate srcu sections using CONFIG_SRCU
Date: Sun, 4 Jan 2015 08:14:16 -0800 [thread overview]
Message-ID: <20150104161416.GA5280@linux.vnet.ibm.com> (raw)
In-Reply-To: <1420364152.26772.0.camel@ellerman.id.au>
On Sun, Jan 04, 2015 at 08:35:52PM +1100, Michael Ellerman wrote:
> On Tue, 2014-12-30 at 13:54 -0500, Pranith Kumar wrote:
> > On Tue, Dec 30, 2014 at 1:50 PM, Peter Zijlstra <peterz@infradead.org> wrote:
> > > On Tue, Dec 30, 2014 at 12:46:22AM -0500, Pranith Kumar wrote:
> > >> Isolate the SRCU functions and data structures within CONFIG_SRCU so that there
> > >> is a compile time failure if srcu is used when not enabled. This was decided to
> > >> be better than waiting until link time for a failure to occur.
> > >
> > > Why?
> >
> > This is part of the kernel tinification efforts. The first patch was
> > posted here: https://lkml.org/lkml/2014/12/4/848. This patch enables a
> > compile time failure instead of a link time failure.
>
> The punch line was:
>
> "so the savings are about ~2000 bytes."
>
> Which is utterly not worth the effort IMO. There have got to be more attractive
> targets for tinification than this.
There probably are. But if the tinification effort is to come anywhere
near reaching its goals, it is going to need 2000-byte savings, especially
on the small systems that are this effort's main target.
That said, Peter's suggestion of falling back to the link-time diagnostic
does simplify things a bit, and might be a good approach.
Thanx, Paul
next prev parent reply other threads:[~2015-01-04 16:14 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-12-30 5:46 [PATCH] assoc_array: Include rcupdate.h for call_rcu() definition Pranith Kumar
2014-12-30 5:46 ` [PATCH v2] srcu: Isolate srcu sections using CONFIG_SRCU Pranith Kumar
2014-12-30 5:46 ` Pranith Kumar
2014-12-30 18:50 ` Peter Zijlstra
2014-12-30 18:50 ` Peter Zijlstra
2014-12-30 18:54 ` Pranith Kumar
2014-12-30 18:54 ` Pranith Kumar
2014-12-30 19:07 ` Peter Zijlstra
2014-12-30 19:07 ` Peter Zijlstra
2014-12-31 13:19 ` Paul E. McKenney
2014-12-31 13:19 ` Paul E. McKenney
2015-01-04 9:35 ` Michael Ellerman
2015-01-04 9:35 ` Michael Ellerman
2015-01-04 16:14 ` Paul E. McKenney [this message]
2015-01-04 16:14 ` Paul E. McKenney
2015-01-05 4:57 ` Josh Triplett
2015-01-05 4:57 ` Josh Triplett
2015-01-05 16:01 ` [PATCH] assoc_array: Include rcupdate.h for call_rcu() definition David Howells
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=20150104161416.GA5280@linux.vnet.ibm.com \
--to=paulmck@linux.vnet.ibm.com \
--cc=anton@samba.org \
--cc=bobby.prani@gmail.com \
--cc=borntraeger@de.ibm.com \
--cc=dwalter@google.com \
--cc=heiko.carstens@de.ibm.com \
--cc=jfrei@linux.vnet.ibm.com \
--cc=josh@joshtriplett.org \
--cc=laijs@cn.fujitsu.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-s390@vger.kernel.org \
--cc=linux390@de.ibm.com \
--cc=linuxppc-dev@lists.ozlabs.org \
--cc=mathieu.desnoyers@efficios.com \
--cc=mingo@kernel.org \
--cc=mpe@ellerman.id.au \
--cc=nacc@linux.vnet.ibm.com \
--cc=paulus@samba.org \
--cc=peterz@infradead.org \
--cc=rostedt@goodmis.org \
--cc=schwidefsky@de.ibm.com \
--cc=scottwood@freescale.com \
--cc=srivatsa.bhat@linux.vnet.ibm.com \
--cc=tiejun.chen@windriver.com \
--cc=vincent.guittot@linaro.org \
--cc=zhong@linux.vnet.ibm.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 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.