From: Nick Piggin <nickpiggin@yahoo.com.au>
To: Shaohua Li <shaohua.li@intel.com>
Cc: Ashok Raj <ashok.raj@intel.com>,
lkml <linux-kernel@vger.kernel.org>, akpm <akpm@osdl.org>,
Ingo Molnar <mingo@elte.hu>
Subject: Re: [PATCH]CPU hotplug breaks wake_up_new_task
Date: Tue, 31 May 2005 19:08:46 +1000 [thread overview]
Message-ID: <429C299E.3030805@yahoo.com.au> (raw)
In-Reply-To: <1117530667.4025.4.camel@linux-hp.sh.intel.com>
Shaohua Li wrote:
> On Tue, 2005-05-31 at 18:50 +1000, Nick Piggin wrote:
>
>>Shaohua Li wrote:
>>
>>
>>>I must be over considering. Ok, how does this updated one look?
>>>
>>>
>>
>>Looks like you've found a race, alright. Nice work!
>>
>>I think it would be preferable to do the check in kernel/fork.c,
>>after the tasklist lock is taken (and you'll need to rediff the
>>patch for the -mm tree).
>
> It seems there is still a race between copy_process and wake_up_new_task
> to me (cpu offline after copy_process). Am I missing anything?
>
Offlining the CPU takes the tasklist lock to migrate off tasks.
So either the CPU will be offline first, in which case the a
check in kernel/fork.c will pick that up; or the task will be
added to the tasklist first, in which case CPU hotplug should
correctly migrate it away.
I think?
--
SUSE Labs, Novell Inc.
Send instant messages to your online friends http://au.messenger.yahoo.com
next prev parent reply other threads:[~2005-05-31 9:09 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-05-31 7:35 [PATCH]CPU hotplug breaks wake_up_new_task Shaohua Li
2005-05-31 8:00 ` Ashok Raj
2005-05-31 8:35 ` Shaohua Li
2005-05-31 8:50 ` Nick Piggin
2005-05-31 9:11 ` Shaohua Li
2005-05-31 9:08 ` Nick Piggin [this message]
2005-05-31 9:40 ` Srivatsa Vaddagiri
2005-05-31 9:46 ` Nick Piggin
2005-05-31 10:40 ` Srivatsa Vaddagiri
2005-05-31 10:49 ` Nick Piggin
-- strict thread matches above, loose matches on Subject: below --
2005-05-31 11:41 Li, Shaohua
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=429C299E.3030805@yahoo.com.au \
--to=nickpiggin@yahoo.com.au \
--cc=akpm@osdl.org \
--cc=ashok.raj@intel.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@elte.hu \
--cc=shaohua.li@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