From: Ashok Raj <ashok.raj@intel.com>
To: Andrew Morton <akpm@osdl.org>
Cc: Ashok Raj <ashok.raj@intel.com>,
olel@ans.pl, venkatesh.pallipadi@intel.com,
linux-kernel@vger.kernel.org, suresh.b.siddha@intel.com,
rajesh.shah@intel.com, ak@muc.de
Subject: Re: More than 8 CPUs detected and CONFIG_X86_PC cannot handle it on 2.6.16-rc6
Date: Mon, 13 Mar 2006 12:05:52 -0800 [thread overview]
Message-ID: <20060313120552.A25020@unix-os.sc.intel.com> (raw)
In-Reply-To: <20060313115155.24dfb6f3.akpm@osdl.org>; from akpm@osdl.org on Mon, Mar 13, 2006 at 11:51:55AM -0800
On Mon, Mar 13, 2006 at 11:51:55AM -0800, Andrew Morton wrote:
>
> One of the main reasons for turning on CONFIG_HOTPLUG_CPU on x86 is
> actually for suspend-to-disk on SMP. I don't think it's desirable to force
> all those little machines to use X86_GENERICARCH || X86_BIGSMP. And it'd
> be good to make that warning go away for 2.6.16.
But we cant use X86_PC since it uses logical flat mode for IPI's that could
cause hangup's if we deliver IPI's using IPI broadcast shortcut.
In i386 we do have an alternate that would use mask value to deliver IPI's
but Andi's recommendataion was to use flat physical mode just like what we
do for X86_64.
Other than the IPI mode, are there any other things that hurt small systems
by choosing bigsmp mode?
Venki suggested we could make it !X86_PC instead of listing
GENERICARCH or BIGSMP separately.
--
Cheers,
Ashok Raj
- Open Source Technology Center
When CONFIG_HOTPLUG_CPU is turned on we always use physflat mode (bigsmp) even
when #of CPUs are less than 8 to avoid sending IPI to offline processors.
Without having BIGSMP on it spits out a warning during boot on systems that
seems misleading, since it complains even on systems that have less
than 8 cpus.
Signed-off-by: Ashok Raj <ashok.raj@intel.com>
---------------------------------------------------------
arch/i386/Kconfig | 2 +-
1 files changed, 1 insertion(+), 1 deletion(-)
Index: linux-2.6.16-rc6-mm1/arch/i386/Kconfig
===================================================================
--- linux-2.6.16-rc6-mm1.orig/arch/i386/Kconfig
+++ linux-2.6.16-rc6-mm1/arch/i386/Kconfig
@@ -760,7 +760,7 @@ config PHYSICAL_START
config HOTPLUG_CPU
bool "Support for hot-pluggable CPUs (EXPERIMENTAL)"
- depends on SMP && HOTPLUG && EXPERIMENTAL && !X86_VOYAGER
+ depends on SMP && HOTPLUG && EXPERIMENTAL && !X86_VOYAGER && !X86_PC
---help---
Say Y here to experiment with turning CPUs off and on. CPUs
can be controlled through /sys/devices/system/cpu.
next prev parent reply other threads:[~2006-03-13 20:06 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-03-12 2:04 More than 8 CPUs detected and CONFIG_X86_PC cannot handle it on 2.6.16-rc6 Krzysztof Oledzki
2006-03-12 5:03 ` Andrew Morton
2006-03-12 11:04 ` Krzysztof Oledzki
2006-03-12 11:25 ` Andrew Morton
2006-03-12 13:05 ` Krzysztof Oledzki
2006-03-12 15:35 ` Venkatesh Pallipadi
2006-03-12 21:13 ` Krzysztof Oledzki
2006-03-12 22:30 ` Andrew Morton
2006-03-13 19:36 ` Ashok Raj
2006-03-13 19:51 ` Andrew Morton
2006-03-13 20:05 ` Ashok Raj [this message]
2006-03-13 22:22 ` Andrew Morton
2006-03-13 23:04 ` Ashok Raj
2006-03-15 5:44 ` Nathan Lynch
2006-03-15 6:18 ` Shaohua Li
2006-03-15 7:31 ` Andrew Morton
2006-03-15 9:37 ` [PATCH] No need to protect current->group_info in sys_getgroups(), in_group_p() and in_egroup_p() Eric Dumazet
2006-03-20 19:09 ` [PATCH] Use unsigned int types for a faster bsearch Eric Dumazet
2006-03-22 5:06 ` [PATCH] Use __read_mostly on some hot fs variables Eric Dumazet
2006-03-22 5:15 ` Nick Piggin
2006-03-22 6:23 ` [RFC, PATCH] avoid some atomics in open()/close() for monothreaded processes Eric Dumazet
2006-03-22 6:41 ` Andrew Morton
2006-03-22 6:59 ` Eric Dumazet
2006-03-22 7:03 ` Andrew Morton
2006-03-15 18:09 ` More than 8 CPUs detected and CONFIG_X86_PC cannot handle it on 2.6.16-rc6 Ashok Raj
-- strict thread matches above, loose matches on Subject: below --
2006-03-15 10:50 Chuck Ebbert
2006-03-15 15:44 ` Krzysztof Oledzki
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=20060313120552.A25020@unix-os.sc.intel.com \
--to=ashok.raj@intel.com \
--cc=ak@muc.de \
--cc=akpm@osdl.org \
--cc=linux-kernel@vger.kernel.org \
--cc=olel@ans.pl \
--cc=rajesh.shah@intel.com \
--cc=suresh.b.siddha@intel.com \
--cc=venkatesh.pallipadi@intel.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