From: "Leonidas ." <leonidas137@gmail.com>
To: Clemens Ladisch <clemens@ladisch.de>
Cc: Valdis.Kletnieks@vt.edu, linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: Can current macro be accessed from interrupt context?
Date: Fri, 23 Oct 2009 02:34:15 -0700 [thread overview]
Message-ID: <f22d86810910230234qed58b28g920a98bb3720b146@mail.gmail.com> (raw)
In-Reply-To: <4AE165A1.5080204@ladisch.de>
> There is no fixed association between your tasks and the CPUs they are
> running on. It is possible for two of your threads to be executed on
> the same CPU (one after the other), or for one thread to migrate between
> CPUs.
Yes, you are right. I had not thought about thread migration etc and was
painting a rather simple picture of things.
>
> The task that was interrupted is probably some entirely different task
> (the X server, the shell, your mail reader, some kernel thread, or
> any of the other tasks running on your system).
>
> It is possible for your interrupt handler to be called for some device
> request that belongs to one of your tasks that is currently running on
> another CPU, so you won't be able to manage that data without locking.
>
Yes, this is pretty much points towards using per-cpu data.
Seems like my thought experiment will lead to an early demise.
Thanks for the explanation.
-Leo.
prev parent reply other threads:[~2009-10-23 9:34 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-10-22 11:10 Leonidas .
2009-10-22 11:27 ` Frederic Weisbecker
2009-10-22 11:43 ` Leonidas .
2009-10-22 11:49 ` Leonidas .
2009-10-22 12:06 ` Frederic Weisbecker
2009-10-22 13:37 ` Leonidas .
2009-10-22 13:45 ` Arjan van de Ven
2009-10-22 15:17 ` Valdis.Kletnieks
2009-10-22 17:46 ` Leonidas .
2009-10-22 18:12 ` Leonidas .
2009-10-23 8:13 ` Clemens Ladisch
2009-10-23 9:34 ` Leonidas . [this message]
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=f22d86810910230234qed58b28g920a98bb3720b146@mail.gmail.com \
--to=leonidas137@gmail.com \
--cc=Valdis.Kletnieks@vt.edu \
--cc=clemens@ladisch.de \
--cc=linux-kernel@vger.kernel.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
all inboxes | Powered by JetHome®