From: "H. Peter Anvin" <hpa@zytor.com>
To: Andy Lutomirski <luto@amacapital.net>, Toshi Kani <toshi.kani@hp.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>,
Arnd Bergmann <arnd@arndb.de>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Juergen Gross <jgross@suse.com>,
Stefan Bader <stefan.bader@canonical.com>,
Henrique de Moraes Holschuh <hmh@hmh.eng.br>,
Yigal Korman <yigal@plexistor.com>,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Subject: Re: [PATCH v2 2/6] x86, mm, pat: Change reserve_memtype() to handle WT
Date: Wed, 10 Sep 2014 14:39:03 -0700 [thread overview]
Message-ID: <5410C4F7.4080704@zytor.com> (raw)
In-Reply-To: <CALCETrV4DEr7tQUPCSzJMjBwgJ3-Xgcw8PFt_CCDbMoWRQ4Uug@mail.gmail.com>
On 09/10/2014 02:27 PM, Andy Lutomirski wrote:
>>
>> That's possible, but the only benefit is that we can enable WT on
>> pre-PAT systems, which I do not think anyone cares now... WB & UC work
>> on pre-PAT systems. WC & WT need PAT. I think this requirement is
>> reasonable.
>
> It might end up being a cleanup, though. A whole bunch of
> rarely-exercised if (!pat_enabled) things would go away.
>
Yes. Don't think of it as PAT vs non-PAT. Think of it as a specific
set of cache types available on different processors. The fact that you
may have to frob an MSR to initialize it is almost trivial in comparison.
-hpa
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
WARNING: multiple messages have this Message-ID (diff)
From: "H. Peter Anvin" <hpa@zytor.com>
To: Andy Lutomirski <luto@amacapital.net>, Toshi Kani <toshi.kani@hp.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>,
Arnd Bergmann <arnd@arndb.de>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Juergen Gross <jgross@suse.com>,
Stefan Bader <stefan.bader@canonical.com>,
Henrique de Moraes Holschuh <hmh@hmh.eng.br>,
Yigal Korman <yigal@plexistor.com>,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Subject: Re: [PATCH v2 2/6] x86, mm, pat: Change reserve_memtype() to handle WT
Date: Wed, 10 Sep 2014 14:39:03 -0700 [thread overview]
Message-ID: <5410C4F7.4080704@zytor.com> (raw)
In-Reply-To: <CALCETrV4DEr7tQUPCSzJMjBwgJ3-Xgcw8PFt_CCDbMoWRQ4Uug@mail.gmail.com>
On 09/10/2014 02:27 PM, Andy Lutomirski wrote:
>>
>> That's possible, but the only benefit is that we can enable WT on
>> pre-PAT systems, which I do not think anyone cares now... WB & UC work
>> on pre-PAT systems. WC & WT need PAT. I think this requirement is
>> reasonable.
>
> It might end up being a cleanup, though. A whole bunch of
> rarely-exercised if (!pat_enabled) things would go away.
>
Yes. Don't think of it as PAT vs non-PAT. Think of it as a specific
set of cache types available on different processors. The fact that you
may have to frob an MSR to initialize it is almost trivial in comparison.
-hpa
next prev parent reply other threads:[~2014-09-10 21:39 UTC|newest]
Thread overview: 80+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-10 16:51 [PATCH v2 0/6] Support Write-Through mapping on x86 Toshi Kani
2014-09-10 16:51 ` Toshi Kani
2014-09-10 16:51 ` [PATCH v2 1/6] x86, mm, pat: Set WT to PA4 slot of PAT MSR Toshi Kani
2014-09-10 16:51 ` Toshi Kani
2014-09-12 19:33 ` Konrad Rzeszutek Wilk
2014-09-12 19:33 ` Konrad Rzeszutek Wilk
2014-09-12 20:45 ` Toshi Kani
2014-09-12 20:45 ` Toshi Kani
2014-09-10 16:51 ` [PATCH v2 2/6] x86, mm, pat: Change reserve_memtype() to handle WT Toshi Kani
2014-09-10 16:51 ` Toshi Kani
2014-09-10 18:26 ` Andy Lutomirski
2014-09-10 18:26 ` Andy Lutomirski
2014-09-10 19:14 ` H. Peter Anvin
2014-09-10 19:14 ` H. Peter Anvin
2014-09-10 19:30 ` Toshi Kani
2014-09-10 19:30 ` Toshi Kani
2014-09-10 20:14 ` H. Peter Anvin
2014-09-10 20:14 ` H. Peter Anvin
2014-09-10 20:30 ` Toshi Kani
2014-09-10 20:30 ` Toshi Kani
2014-09-10 21:06 ` Andy Lutomirski
2014-09-10 21:06 ` Andy Lutomirski
2014-09-10 21:11 ` Toshi Kani
2014-09-10 21:11 ` Toshi Kani
2014-09-10 21:27 ` Andy Lutomirski
2014-09-10 21:27 ` Andy Lutomirski
2014-09-10 21:25 ` Toshi Kani
2014-09-10 21:25 ` Toshi Kani
2014-09-10 21:39 ` H. Peter Anvin
2014-09-10 21:39 ` H. Peter Anvin
2014-09-10 21:39 ` H. Peter Anvin [this message]
2014-09-10 21:39 ` H. Peter Anvin
2014-09-10 21:47 ` Toshi Kani
2014-09-10 21:47 ` Toshi Kani
2014-09-10 22:00 ` H. Peter Anvin
2014-09-10 22:00 ` H. Peter Anvin
2014-09-10 23:24 ` Toshi Kani
2014-09-10 23:24 ` Toshi Kani
2014-09-10 20:31 ` Andy Lutomirski
2014-09-10 20:31 ` Andy Lutomirski
2014-09-12 19:41 ` Konrad Rzeszutek Wilk
2014-09-12 19:41 ` Konrad Rzeszutek Wilk
2014-09-10 16:51 ` [PATCH v2 3/6] x86, mm, asm-gen: Add ioremap_wt() for WT Toshi Kani
2014-09-10 16:51 ` Toshi Kani
2014-09-10 18:29 ` Andy Lutomirski
2014-09-10 18:29 ` Andy Lutomirski
2014-09-10 19:40 ` Toshi Kani
2014-09-10 19:40 ` Toshi Kani
2014-09-10 20:08 ` Andy Lutomirski
2014-09-10 20:08 ` Andy Lutomirski
2014-09-12 19:42 ` Konrad Rzeszutek Wilk
2014-09-12 19:42 ` Konrad Rzeszutek Wilk
2014-09-10 16:51 ` [PATCH v2 4/6] x86, mm: Add set_memory_wt() " Toshi Kani
2014-09-10 16:51 ` Toshi Kani
2014-09-12 19:47 ` Konrad Rzeszutek Wilk
2014-09-12 19:47 ` Konrad Rzeszutek Wilk
2014-09-10 16:51 ` [PATCH v2 5/6] x86, mm, pat: Add pgprot_writethrough() " Toshi Kani
2014-09-10 16:51 ` Toshi Kani
2014-09-12 19:47 ` Konrad Rzeszutek Wilk
2014-09-12 19:47 ` Konrad Rzeszutek Wilk
2014-09-10 16:51 ` [PATCH v2 6/6] x86, pat: Update documentation for WT changes Toshi Kani
2014-09-10 16:51 ` Toshi Kani
2014-09-10 18:30 ` Andy Lutomirski
2014-09-10 18:30 ` Andy Lutomirski
2014-09-10 20:12 ` Toshi Kani
2014-09-10 20:12 ` Toshi Kani
2014-09-10 20:29 ` Andy Lutomirski
2014-09-10 20:29 ` Andy Lutomirski
2014-09-10 21:34 ` Toshi Kani
2014-09-10 21:34 ` Toshi Kani
2014-09-15 21:19 ` Toshi Kani
2014-09-15 21:19 ` Toshi Kani
2014-09-16 1:22 ` Andy Lutomirski
2014-09-16 1:22 ` Andy Lutomirski
2014-09-16 16:52 ` Toshi Kani
2014-09-16 16:52 ` Toshi Kani
2014-09-16 21:45 ` Yigal Korman
2014-09-16 21:45 ` Yigal Korman
2014-09-16 22:13 ` Toshi Kani
2014-09-16 22:13 ` Toshi Kani
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=5410C4F7.4080704@zytor.com \
--to=hpa@zytor.com \
--cc=akpm@linux-foundation.org \
--cc=arnd@arndb.de \
--cc=hmh@hmh.eng.br \
--cc=jgross@suse.com \
--cc=konrad.wilk@oracle.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=luto@amacapital.net \
--cc=mingo@redhat.com \
--cc=stefan.bader@canonical.com \
--cc=tglx@linutronix.de \
--cc=toshi.kani@hp.com \
--cc=yigal@plexistor.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 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.