From: Mike Rapoport <rppt@kernel.org>
To: Matthew Wilcox <willy@infradead.org>
Cc: Jessica Clarke <jrtc27@jrtc27.com>,
John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>,
Tony Luck <tony.luck@intel.com>,
linux-ia64@vger.kernel.org, Anatoly Pugachev <matorola@gmail.com>,
Sergei Trofimovich <slyfox@gentoo.org>,
linux-mm@kvack.org, Frank Scheiner <frank.scheiner@web.de>,
Mike Rapoport <rppt@linux.ibm.com>
Subject: Re: [PATCH v5] arch/ia64: Restore arch-specific pgd_offset_k implementation
Date: Thu, 13 Aug 2020 22:21:10 +0000 [thread overview]
Message-ID: <20200813222110.GE752365@kernel.org> (raw)
In-Reply-To: <20200813213631.GQ17456@casper.infradead.org>
On Thu, Aug 13, 2020 at 10:36:31PM +0100, Matthew Wilcox wrote:
> On Thu, Aug 13, 2020 at 11:55:21PM +0300, Mike Rapoport wrote:
> > +/*
> > + * In the kernel's mapped region we know everything is in region number 5, so
> > + * as an optimisation its PGD already points to the area for that region.
>
> Is it actually an optimisation? Are there any benchmarks where this
> makes any difference whatsoever? Or should the comment be closer to
>
> /* ia64 is gratuitously different. Cope with it. */
It better suits arch/ia64/Kconfig ;-)
diff --git a/arch/ia64/Kconfig b/arch/ia64/Kconfig
index 5b4ec80bf586..205cdb91a6d5 100644
--- a/arch/ia64/Kconfig
+++ b/arch/ia64/Kconfig
@@ -62,6 +62,7 @@ config IA64
the 32-bit X86 line. The IA-64 Linux project has a home
page at <http://www.linuxia64.org/> and a mailing list at
<linux-ia64@vger.kernel.org>.
+ IA-64 is gratuitously different. Cope with it.
> I might suggest that pgd be changed to be the same as every other pgd
> in the system, and every other architecture.
I did some grepping and got lost in IA-64 assembly, so I agree with
Jessica that it would open a can of worms.
--
Sincerely yours,
Mike.
WARNING: multiple messages have this Message-ID (diff)
From: Mike Rapoport <rppt@kernel.org>
To: Matthew Wilcox <willy@infradead.org>
Cc: Jessica Clarke <jrtc27@jrtc27.com>,
John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>,
Tony Luck <tony.luck@intel.com>,
linux-ia64@vger.kernel.org, Anatoly Pugachev <matorola@gmail.com>,
Sergei Trofimovich <slyfox@gentoo.org>,
linux-mm@kvack.org, Frank Scheiner <frank.scheiner@web.de>,
Mike Rapoport <rppt@linux.ibm.com>
Subject: Re: [PATCH v5] arch/ia64: Restore arch-specific pgd_offset_k implementation
Date: Fri, 14 Aug 2020 01:21:10 +0300 [thread overview]
Message-ID: <20200813222110.GE752365@kernel.org> (raw)
In-Reply-To: <20200813213631.GQ17456@casper.infradead.org>
On Thu, Aug 13, 2020 at 10:36:31PM +0100, Matthew Wilcox wrote:
> On Thu, Aug 13, 2020 at 11:55:21PM +0300, Mike Rapoport wrote:
> > +/*
> > + * In the kernel's mapped region we know everything is in region number 5, so
> > + * as an optimisation its PGD already points to the area for that region.
>
> Is it actually an optimisation? Are there any benchmarks where this
> makes any difference whatsoever? Or should the comment be closer to
>
> /* ia64 is gratuitously different. Cope with it. */
It better suits arch/ia64/Kconfig ;-)
diff --git a/arch/ia64/Kconfig b/arch/ia64/Kconfig
index 5b4ec80bf586..205cdb91a6d5 100644
--- a/arch/ia64/Kconfig
+++ b/arch/ia64/Kconfig
@@ -62,6 +62,7 @@ config IA64
the 32-bit X86 line. The IA-64 Linux project has a home
page at <http://www.linuxia64.org/> and a mailing list at
<linux-ia64@vger.kernel.org>.
+ IA-64 is gratuitously different. Cope with it.
> I might suggest that pgd be changed to be the same as every other pgd
> in the system, and every other architecture.
I did some grepping and got lost in IA-64 assembly, so I agree with
Jessica that it would open a can of worms.
--
Sincerely yours,
Mike.
next prev parent reply other threads:[~2020-08-13 22:21 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-13 20:55 [PATCH v5] arch/ia64: Restore arch-specific pgd_offset_k implementation Mike Rapoport
2020-08-13 20:55 ` Mike Rapoport
2020-08-13 21:36 ` Matthew Wilcox
2020-08-13 21:36 ` Matthew Wilcox
2020-08-13 21:44 ` Jessica Clarke
2020-08-13 21:44 ` Jessica Clarke
2020-08-13 22:21 ` Mike Rapoport [this message]
2020-08-13 22:21 ` Mike Rapoport
2020-08-17 7:33 ` Mike Rapoport
2020-08-17 7:33 ` Mike Rapoport
2020-08-17 16:05 ` Luck, Tony
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=20200813222110.GE752365@kernel.org \
--to=rppt@kernel.org \
--cc=frank.scheiner@web.de \
--cc=glaubitz@physik.fu-berlin.de \
--cc=jrtc27@jrtc27.com \
--cc=linux-ia64@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=matorola@gmail.com \
--cc=rppt@linux.ibm.com \
--cc=slyfox@gentoo.org \
--cc=tony.luck@intel.com \
--cc=willy@infradead.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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.