From: Andy Whitcroft <apw@shadowen.org>
To: schwidefsky@de.ibm.com
Cc: akpm@osdl.org, virtualization@lists.osdl.org,
frankeh@watson.ibm.com, rhim@cc.gateh.edu,
nickpiggin@yahoo.com.au, Dave Hansen <haveblue@us.ibm.com>,
linux-kernel@vger.kernel.org
Subject: Re: [patch 3/9] Guest page hinting: volatile page cache.
Date: Fri, 01 Sep 2006 16:48:11 +0100 [thread overview]
Message-ID: <44F8563B.3050505@shadowen.org> (raw)
In-Reply-To: <1157124674.21733.13.camel@localhost>
Martin Schwidefsky wrote:
> On Fri, 2006-09-01 at 07:57 -0700, Dave Hansen wrote:
>>> +#define PG_state_change 21 /* HV page state is changing. */
>>> +#define PG_discarded 22 /* HV page has been discarded. */
>> We're already desperately short on page flags on 32-bit architectures.
>> It seems a wee bit silly to add two arch-generic flags for what is a
>> very specialized arch-specific feature at this point.
>
> There are even three additional page flags if you apply the full set of
> patches.
>
>> I know that there are 32-bit s390 kernels, but would this be a
>> reasonable feature to restrict to only 64-bit kernels? That might be a
>> decent compromise.
>
> Yes, it is definitly an option to make this a 64-bit only features. In
> particular because the ESSA instruction that is used on s390 is only
> available in zarch mode (=64 bit).
Wow. Well there are only 7 extra bits available in 64 bit mode (the
FIELDS area is larger on 64bit machines). Do we really, really need
three new bits. What are they being used for here.
-apw
WARNING: multiple messages have this Message-ID (diff)
From: Andy Whitcroft <apw@shadowen.org>
To: schwidefsky@de.ibm.com
Cc: Dave Hansen <haveblue@us.ibm.com>,
linux-kernel@vger.kernel.org, virtualization@lists.osdl.org,
akpm@osdl.org, nickpiggin@yahoo.com.au, frankeh@watson.ibm.com,
rhim@cc.gateh.edu
Subject: Re: [patch 3/9] Guest page hinting: volatile page cache.
Date: Fri, 01 Sep 2006 16:48:11 +0100 [thread overview]
Message-ID: <44F8563B.3050505@shadowen.org> (raw)
In-Reply-To: <1157124674.21733.13.camel@localhost>
Martin Schwidefsky wrote:
> On Fri, 2006-09-01 at 07:57 -0700, Dave Hansen wrote:
>>> +#define PG_state_change 21 /* HV page state is changing. */
>>> +#define PG_discarded 22 /* HV page has been discarded. */
>> We're already desperately short on page flags on 32-bit architectures.
>> It seems a wee bit silly to add two arch-generic flags for what is a
>> very specialized arch-specific feature at this point.
>
> There are even three additional page flags if you apply the full set of
> patches.
>
>> I know that there are 32-bit s390 kernels, but would this be a
>> reasonable feature to restrict to only 64-bit kernels? That might be a
>> decent compromise.
>
> Yes, it is definitly an option to make this a 64-bit only features. In
> particular because the ESSA instruction that is used on s390 is only
> available in zarch mode (=64 bit).
Wow. Well there are only 7 extra bits available in 64 bit mode (the
FIELDS area is larger on 64bit machines). Do we really, really need
three new bits. What are they being used for here.
-apw
next prev parent reply other threads:[~2006-09-01 15:48 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-09-01 11:09 [patch 3/9] Guest page hinting: volatile page cache Martin Schwidefsky
2006-09-01 14:54 ` Dave Hansen
2006-09-01 14:54 ` Dave Hansen
2006-09-01 15:29 ` Martin Schwidefsky
2006-09-01 15:37 ` Dave Hansen
2006-09-01 14:57 ` Dave Hansen
2006-09-01 15:31 ` Martin Schwidefsky
2006-09-01 15:48 ` Andy Whitcroft [this message]
2006-09-01 15:48 ` Andy Whitcroft
2006-09-01 16:04 ` Martin Schwidefsky
2006-09-01 16:04 ` Martin Schwidefsky
2006-09-01 16:18 ` Dave Hansen
2006-09-01 16:18 ` Dave Hansen
2006-09-01 16:25 ` Martin Schwidefsky
2006-09-01 16:37 ` Dave Hansen
2006-09-01 16:37 ` Dave Hansen
2006-09-01 16:56 ` Martin Schwidefsky
2006-09-01 17:16 ` Dave Hansen
2006-09-01 17:16 ` Dave Hansen
2006-09-01 17:42 ` Martin Schwidefsky
2006-09-01 18:03 ` Dave Hansen
2006-09-01 18:04 ` Martin Schwidefsky
2006-09-01 18:23 ` Dave Hansen
2006-09-01 18:23 ` Dave Hansen
2006-09-01 18:31 ` Martin Schwidefsky
2006-09-01 18:41 ` Dave Hansen
2006-09-04 11:21 ` Martin Schwidefsky
2006-09-05 18:27 ` Dave Hansen
2006-09-06 10:49 ` Martin Schwidefsky
2006-09-01 16:29 ` Dave Hansen
2006-09-01 17:02 ` Martin Schwidefsky
2006-09-01 17:05 ` Dave Hansen
2006-09-13 18:21 ` Zachary Amsden
2006-09-14 8:56 ` Martin Schwidefsky
2006-09-14 9:23 ` Zachary Amsden
2006-09-15 8:36 ` Martin Schwidefsky
-- strict thread matches above, loose matches on Subject: below --
2006-09-15 17:50 Chuck Ebbert
2006-09-18 8:08 ` Martin Schwidefsky
2006-08-24 14:30 Martin Schwidefsky, Martin Schwidefsky, Hubertus Franke, Himanshu Raj
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