From: Andy Lutomirski <luto@kernel.org>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>,
Andrew Cooper <andrew.cooper3@citrix.com>,
Jan Beulich <jbeulich@suse.com>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
Juergen Gross <jgross@suse.com>,
Stefano Stabellini <sstabellini@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Steven Rostedt <rostedt@goodmis.org>,
LKML <linux-kernel@vger.kernel.org>,
"H. Peter Anvin" <hpa@zytor.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@kernel.org>, Borislav Petkov <bp@alien8.de>,
Joel Fernandes <joel@joelfernandes.org>,
He Zhe <zhe.he@windriver.com>
Subject: Re: [RFC][PATCH] tracing/x86: Save CR2 before tracing irqsoff on error_entry
Date: Thu, 21 Mar 2019 11:38:25 -0700 [thread overview]
Message-ID: <CALCETrVUUbSv_pQyVXUSmKV5Jw9DN1y2ib4zGix5Y-9DXw2nGg@mail.gmail.com> (raw)
In-Reply-To: <CAHk-=wjEHqY1+DxJ-_oNWTuTNQwMPtJKJh_HE=e1F60V+TwUfQ@mail.gmail.com>
On Thu, Mar 21, 2019 at 11:33 AM Linus Torvalds
<torvalds@linux-foundation.org> wrote:
>
> On Thu, Mar 21, 2019 at 11:21 AM Andy Lutomirski <luto@kernel.org> wrote:
> >
> > I dunno. Lots of people at least use to have serious commercial interest in it.
>
> Yes, it used to be a big deal. But full virtualization has gotten a
> lot more common and better.
>
> > Hey Xen folks, how close are we to being able to say "if you want to
> > run a new kernel, you need to switch to PVH or similar"?
>
> I'd also like to know if we could perhaps at least limit PV to just
> the thing that people care most deeply about.
>
> For example, maybe people notice that they really deeply care about
> the PV spinlocks because they help a lot for some loads, but don't
> care so much about the low-level CPU PV stuff any more because modern
> CPUs do _those_ things so well these days.
>
> So it might not be an all-or-nothing thing, but a gradual "let's stop
> supporting xyz under PV, because it causes pain and isn't worth it".
>
I suspect we'll want PV spinlocks and other goodies like PV TLB
shootdown for a long time. The stuff I'd like to kill eventually is
the PV "I'm not actually at CPL 0 so I'm faking it" part.
next prev parent reply other threads:[~2019-03-21 18:38 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-21 2:15 [RFC][PATCH] tracing/x86: Save CR2 before tracing irqsoff on error_entry Steven Rostedt
2019-03-21 8:33 ` Peter Zijlstra
2019-03-21 9:02 ` Peter Zijlstra
2019-03-21 10:45 ` Peter Zijlstra
2019-03-21 13:32 ` Steven Rostedt
2019-03-21 13:55 ` Steven Rostedt
2019-03-21 17:23 ` Linus Torvalds
2019-03-21 17:22 ` Peter Zijlstra
2019-03-21 18:05 ` Andy Lutomirski
2019-03-21 18:10 ` Steven Rostedt
2019-03-21 18:27 ` Andy Lutomirski
2019-03-21 20:50 ` Peter Zijlstra
2019-03-22 2:52 ` Andy Lutomirski
2019-03-21 18:28 ` Peter Zijlstra
2019-03-21 18:55 ` Steven Rostedt
2019-03-21 19:31 ` Peter Zijlstra
2019-03-21 19:50 ` Steven Rostedt
2019-03-21 20:03 ` Peter Zijlstra
2019-03-21 20:11 ` Steven Rostedt
2019-03-21 18:18 ` Linus Torvalds
2019-03-21 18:20 ` Andy Lutomirski
2019-03-21 18:25 ` Linus Torvalds
2019-03-21 18:37 ` Peter Zijlstra
2019-03-21 18:39 ` Andy Lutomirski
2019-03-21 20:00 ` Andrew Cooper
2019-03-21 20:35 ` Steven Rostedt
2019-03-21 18:38 ` Andy Lutomirski [this message]
2019-03-21 18:42 ` Peter Zijlstra
2019-03-21 18:22 ` hpa
2019-03-22 5:54 ` Juergen Gross
2019-03-21 18:27 ` Peter Zijlstra
2019-03-21 18:28 ` Andy Lutomirski
2019-03-21 18:33 ` Peter Zijlstra
2019-03-21 13:04 ` Steven Rostedt
2019-04-17 1:52 ` He Zhe
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