LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Pavel Machek <pavel@ucw.cz>
To: Rusty Russell <rusty@rustcorp.com.au>
Cc: Zachary Amsden <zach@vmware.com>, Andi Kleen <ak@muc.de>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Andrew Morton <akpm@osdl.org>,
	Jeremy Fitzhardinge <jeremy@goop.org>,
	Chris Wright <chrisw@sous-sol.org>
Subject: Re: [PATCH 9/11] Panic delay fix
Date: Wed, 14 Feb 2007 13:26:45 +0100	[thread overview]
Message-ID: <20070214122645.GE22008@elf.ucw.cz> (raw)
In-Reply-To: <1170880572.11736.4.camel@localhost.localdomain>

On Thu 2007-02-08 07:36:12, Rusty Russell wrote:
> On Wed, 2007-02-07 at 12:35 +0000, Pavel Machek wrote:
> > Ugh, it sounds like paravirt is more b0rken then I thought. It should
> > always to the proper delay, then replace those udelays that are not
> > needed on virtualized hardware with something else.
> > 
> > Just magically defining udelay into nop is broken.
> 
> We'd have to audit and figure out what udelays are for hardware and
> which are not, but the evidence is that the vast majority of them are
> for hardware and not needed for virtualization.

You did not time to do the full audit, so you just did #define.

> Changing udelay to "hardware_udelay" or something all over the kernel
> would have delayed the paravirt_ops merge by an infinite amount 8)

And here you claim you could not do the right thing, because people
would notice you are doing huge search/replace without audit, and
would stop you. So you simply hidden it from them :-(.

Plus... udelay() should just work under virtualization, right? You get
slightly slower kernel, but still working, so the "full audit" is not
as hard as you are telling me.

Just replace udelay() with hardware_udelay() on places that matter in
your workload...
								Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

  parent reply	other threads:[~2007-02-14 12:29 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-02-06  3:53 Zachary Amsden
2007-02-06 12:27 ` Andi Kleen
2007-02-06 21:59   ` Zachary Amsden
2007-02-07 12:35     ` Pavel Machek
2007-02-07 20:36       ` Rusty Russell
2007-02-07 22:23         ` Zachary Amsden
2007-02-08 14:43         ` Dmitry Torokhov
2007-02-08 21:26           ` Zachary Amsden
2007-02-08 21:37             ` Dmitry Torokhov
2007-02-14 12:26         ` Pavel Machek [this message]
2007-02-14 19:47           ` Zachary Amsden
2007-02-14 12:52         ` Alan
2007-02-14 20:04           ` Zachary Amsden
2007-02-14 21:34             ` Alan
2007-02-14 21:53               ` Zachary Amsden
2007-02-15  0:33                 ` Alan
2007-02-15 10:17             ` Pavel Machek
2007-02-15 23:42               ` Zachary Amsden
2007-02-15 23:49                 ` Pavel Machek
2007-02-15 23:50                 ` Jeremy Fitzhardinge
2007-02-16  3:22                 ` Rusty Russell
2007-02-07 14:58     ` Dmitry Torokhov
2007-02-07 22:31       ` Zachary Amsden
2007-02-08  8:24         ` Andi Kleen
2007-02-08  9:08           ` Zachary Amsden
2007-02-08 13:33             ` Andi Kleen
2007-02-08 14:41               ` Dmitry Torokhov
2007-02-14 12:49             ` Alan
2007-02-14 22:51 ` Rusty Russell
2007-02-15  0:28   ` Alan
2007-02-15 13:35   ` Dmitry Torokhov

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=20070214122645.GE22008@elf.ucw.cz \
    --to=pavel@ucw.cz \
    --cc=ak@muc.de \
    --cc=akpm@osdl.org \
    --cc=chrisw@sous-sol.org \
    --cc=jeremy@goop.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=rusty@rustcorp.com.au \
    --cc=zach@vmware.com \
    --subject='Re: [PATCH 9/11] Panic delay fix' \
    /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

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).