From: Christoph Lameter <cl-vYTEC60ixJUAvxtiuMwx3w@public.gmane.org>
To: Sam Ravnborg <sam-uyr5N9Q2VtJg9hUCZPvPmw@public.gmane.org>
Cc: Tim Abbott <tabbott-DPNOqEs/LNQ@public.gmane.org>,
Anders Kaseorg <andersk-DPNOqEs/LNQ@public.gmane.org>,
Waseem Daher <wdaher-DPNOqEs/LNQ@public.gmane.org>,
Denys Vlasenko
<vda.linux-gM/Ye1E23mwN+BqQ9rBEUg@public.gmane.org>,
Jeff Arnold <jbarnold-DPNOqEs/LNQ@public.gmane.org>,
Benjamin Herrenschmidt
<benh-XVmvHMARGAS8U2dJNN8I7kB+6BGkLq7r@public.gmane.org>,
Bryan Wu <cooloney-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
Chris Zankel <chris-YvXeqwSYzG2sTnJN9+BGXg@public.gmane.org>,
Cyrill Gorcunov
<gorcunov-GEFAQzZX7r8dnm+yROfE0A@public.gmane.org>,
David Howells <dhowells-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
"David S. Miller" <davem-fT/PcQaiUtIeIZ0/mPfg9Q@public.gmane.org>,
dev-etrax-VrBV9hrLPhE@public.gmane.org,
Geert Uytterhoeven
<geert-Td1EMuHUCqxL1ZNQvxDV9g@public.gmane.org>,
Greg Ungerer <gerg-JBU5SbJe1FlAfugRpC6u6w@public.gmane.org>,
Haavard Skinnemoen
<hskinnemoen-AIFe0yeh4nAAvxtiuMwx3w@public.gmane.org>,
Heiko Carstens
<heiko.carstens-tA70FqPdS9bQT0dZR+AlfA@public.gmane.org>,
Helge Deller <deller-Mmb7MZpHnFY@public.gmane.org>,
Hirokazu Takata <takata-TMSiXQfHlQjsTix1lMzHGQ@public.gmane.org>,
"H. Peter Anvin" <hpa-YMNOUZJC4hwAvxtiuMwx3w@public.gmane.org>,
Ingo Molnar <mingo-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
Jeff Dike <jdike-OPE4K8JWMJJBDgjK7y7TUQ@public.gmane.org>,
Jesper
Subject: Re: [PATCH 6/6] Add support for __read_mostly to linux/cache.h
Date: Fri, 1 May 2009 09:52:18 -0400 (EDT) [thread overview]
Message-ID: <alpine.DEB.1.10.0905010948140.18324@qirst.com> (raw)
In-Reply-To: <20090501094407.GD18326-QabhHTsIXMSnlFQ6Q1D1Y0B+6BGkLq7r@public.gmane.org>
On Fri, 1 May 2009, Sam Ravnborg wrote:
> Are there any specific reason why we do not support read_mostly on all
> architectures?
Not that I know of.
> read_mostly is about grouping rarely written data together
> so what is needed is to introduce this section in the remaining
> archtectures.
>
> Christoph - git log says you did the inital implmentation.
> Do you agree?
Yes.
There is some concern that __read_mostly is needlessly applied to
numerous variables that are not used in hot code paths. This may make
__read_mostly ineffective and actually increase the cache footprint of a
function since global variables are no longer in the same cacheline. If
such a function is called and the caches are cold then two cacheline
fetches have to be done instead of one.
next prev parent reply other threads:[~2009-05-01 13:52 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-04-30 19:32 [PATCH 0/6] macros for section name cleanup Tim Abbott
2009-04-30 19:32 ` [PATCH 1/6] Add new macros for page-aligned data and bss sections Tim Abbott
2009-04-30 19:32 ` [PATCH 2/6] Add new NOSAVE_DATA linker script macro Tim Abbott
2009-04-30 19:32 ` [PATCH 3/6] Add new CACHELINE_ALIGNED_DATA " Tim Abbott
2009-04-30 19:32 ` [PATCH 4/6] Add new INIT_TASK_DATA() " Tim Abbott
2009-04-30 19:32 ` [PATCH 5/6] Add new READ_MOSTLY_DATA(align) " Tim Abbott
2009-04-30 19:32 ` [PATCH 6/6] Add support for __read_mostly to linux/cache.h Tim Abbott
2009-05-01 9:44 ` Sam Ravnborg
[not found] ` <20090501094407.GD18326-QabhHTsIXMSnlFQ6Q1D1Y0B+6BGkLq7r@public.gmane.org>
2009-05-01 13:52 ` Christoph Lameter [this message]
2009-05-01 21:47 ` [microblaze-uclinux] " Edgar E. Iglesias
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=alpine.DEB.1.10.0905010948140.18324@qirst.com \
--to=cl-vytec60ixjuavxtiumwx3w@public.gmane.org \
--cc=andersk-DPNOqEs/LNQ@public.gmane.org \
--cc=benh-XVmvHMARGAS8U2dJNN8I7kB+6BGkLq7r@public.gmane.org \
--cc=chris-YvXeqwSYzG2sTnJN9+BGXg@public.gmane.org \
--cc=cooloney-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org \
--cc=davem-fT/PcQaiUtIeIZ0/mPfg9Q@public.gmane.org \
--cc=deller-Mmb7MZpHnFY@public.gmane.org \
--cc=dev-etrax-VrBV9hrLPhE@public.gmane.org \
--cc=dhowells-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org \
--cc=geert-Td1EMuHUCqxL1ZNQvxDV9g@public.gmane.org \
--cc=gerg-JBU5SbJe1FlAfugRpC6u6w@public.gmane.org \
--cc=gorcunov-GEFAQzZX7r8dnm+yROfE0A@public.gmane.org \
--cc=heiko.carstens-tA70FqPdS9bQT0dZR+AlfA@public.gmane.org \
--cc=hpa-YMNOUZJC4hwAvxtiuMwx3w@public.gmane.org \
--cc=hskinnemoen-AIFe0yeh4nAAvxtiuMwx3w@public.gmane.org \
--cc=jbarnold-DPNOqEs/LNQ@public.gmane.org \
--cc=jdike-OPE4K8JWMJJBDgjK7y7TUQ@public.gmane.org \
--cc=microblaze-uclinux-rVRm/Wmeqae7NGdpmJTKYQ@public.gmane.org \
--cc=mingo-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org \
--cc=sam-uyr5N9Q2VtJg9hUCZPvPmw@public.gmane.org \
--cc=tabbott-DPNOqEs/LNQ@public.gmane.org \
--cc=takata-TMSiXQfHlQjsTix1lMzHGQ@public.gmane.org \
--cc=vda.linux-gM/Ye1E23mwN+BqQ9rBEUg@public.gmane.org \
--cc=wdaher-DPNOqEs/LNQ@public.gmane.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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox