From: John Kacur <jkacur@redhat.com>
To: Peter Xu <peterx@redhat.com>
Cc: Nicolas Saenz Julienne <nsaenzju@redhat.com>,
linux-rt-users@vger.kernel.org, williams@redhat.com,
Punit Agrawal <punitagrawal@gmail.com>
Subject: Re: [PATCH] oslat: Avoid out-of-order memory accesses to precede counter read
Date: Tue, 14 Sep 2021 14:35:56 -0400 (EDT) [thread overview]
Message-ID: <16a169d-ca5-1bd-934d-fe68ea750b9@redhat.com> (raw)
In-Reply-To: <YUDjYX7V8L+B8rxH@t490s>
On Tue, 14 Sep 2021, Peter Xu wrote:
> On Tue, Sep 14, 2021 at 07:55:42PM +0200, Nicolas Saenz Julienne wrote:
> > In arm64 it's possible for the processor to access memory appearing in
> > program order after the read of the counter before the counter has been
> > read. This would skew the counter value to a later point than intended.
> >
> > Fix this my adding an isb() following the counter read instruction.
> >
> > Suggested-by: Punit Agrawal <punitagrawal@gmail.com>
> > Signed-off-by: Nicolas Saenz Julienne <nsaenzju@redhat.com>
>
> Acked-by: Peter Xu <peterx@redhat.com>
>
> --
> Peter Xu
>
>
Signed-off-by: John Kacur <jkacur@redhat.com>
prev parent reply other threads:[~2021-09-14 18:36 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-14 17:55 [PATCH] oslat: Avoid out-of-order memory accesses to precede counter read Nicolas Saenz Julienne
2021-09-14 18:01 ` Peter Xu
2021-09-14 18:35 ` John Kacur [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=16a169d-ca5-1bd-934d-fe68ea750b9@redhat.com \
--to=jkacur@redhat.com \
--cc=linux-rt-users@vger.kernel.org \
--cc=nsaenzju@redhat.com \
--cc=peterx@redhat.com \
--cc=punitagrawal@gmail.com \
--cc=williams@redhat.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