From: "Jan Beulich" <JBeulich@suse.com>
To: George Dunlap <dunlapg@umich.edu>
Cc: Wei Liu <wei.liu2@citrix.com>,
Ian Campbell <ian.campbell@citrix.com>,
Stefano Stabellini <stefano.stabellini@eu.citrix.com>,
Andrew Cooper <andrew.cooper3@citrix.com>,
Ian Jackson <ian.jackson@eu.citrix.com>,
"xen-devel@lists.xen.org" <xen-devel@lists.xen.org>,
Tiejun Chen <tiejun.chen@intel.com>, Keir Fraser <keir@xen.org>
Subject: Re: [v7][PATCH 06/16] hvmloader/pci: skip reserved ranges
Date: Wed, 15 Jul 2015 15:00:37 +0100 [thread overview]
Message-ID: <55A683A5020000780009162B@mail.emea.novell.com> (raw)
In-Reply-To: <CAFLBxZa-A+pJUcMGbi467DLju-Wd3pwvUJTtQA2fm7VfpJz_3g@mail.gmail.com>
>>> On 15.07.15 at 15:40, <dunlapg@umich.edu> wrote:
> On Mon, Jul 13, 2015 at 2:12 PM, Jan Beulich <JBeulich@suse.com> wrote:
>> Therefore I'll not make any further comments on the rest of the
>> patch, but instead outline an allocation model that I think would
>> fit our needs: Subject to the constraints mentioned above, set up
>> a bitmap (maximum size 64k [2Gb = 2^^19 pages needing 2^^19
>> bits], i.e. reasonably small a memory block). Each bit represents a
>> page usable for MMIO: First of all you remove the range from
>> PCI_MEM_END upwards. Then remove all RDM pages. Now do a
>> first pass over all devices, allocating (in the bitmap) space for only
>> the 32-bit MMIO BARs, starting with the biggest one(s), by finding
>> a best fit (i.e. preferably a range not usable by any bigger BAR)
>> from top down. For example, if you have available
>>
>> [f0000000,f8000000)
>> [f9000000,f9001000)
>> [fa000000,fa003000)
>> [fa010000,fa012000)
>>
>> and you're looking for a single page slot, you should end up
>> picking fa002000.
>>
>> After this pass you should be able to do RAM relocation in a
>> single attempt just like we do today (you may still grow the MMIO
>> window if you know you need to and can fit some of the 64-bit
>> BARs in there, subject to said constraints; this is in an attempt
>> to help OSes not comfortable with 64-bit resources).
>>
>> In a 2nd pass you'd then assign 64-bit resources: If you can fit
>> them below 4G (you still have the bitmap left of what you've got
>> available), put them there. Allocation strategy could be the same
>> as above (biggest first), perhaps allowing for some factoring out
>> of logic, but here smallest first probably could work equally well.
>> The main thought to decide between the two is whether it is
>> better to fit as many (small) or as big (in total) as possible a set
>> under 4G. I'd generally expect the former (as many as possible,
>> leaving only a few huge ones to go above 4G) to be the better
>> approach, but that's more a gut feeling than based on hard data.
>
> I agree that it would be more sensible for hvmloader to make a "plan"
> first, and then do the memory reallocation (if it's possible) at one
> time, then go through and actually update the device BARs according to
> the "plan".
>
> However, I don't really see how having a bitmap really helps in this
> case. I would think having a list of free ranges (perhaps aligned by
> powers of two?), sorted small->large, makes the most sense.
I view bitmap vs list as just two different representations, and I
picked the bitmap approach as being more compact storage wise
in case there are many regions to deal with. I'd be fine with a list
approach too, provided lookup times don't become prohibitive.
Jan
next prev parent reply other threads:[~2015-07-15 14:00 UTC|newest]
Thread overview: 119+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-09 5:33 [v7][PATCH 00/16] Fix RMRR Tiejun Chen
2015-07-09 5:33 ` [v7][PATCH 01/16] xen: introduce XENMEM_reserved_device_memory_map Tiejun Chen
2015-07-09 5:33 ` [v7][PATCH 02/16] xen/vtd: create RMRR mapping Tiejun Chen
2015-07-09 5:33 ` [v7][PATCH 03/16] xen/passthrough: extend hypercall to support rdm reservation policy Tiejun Chen
2015-07-10 13:26 ` George Dunlap
2015-07-10 15:01 ` Jan Beulich
2015-07-10 15:07 ` George Dunlap
2015-07-13 6:37 ` Chen, Tiejun
2015-07-13 5:57 ` Chen, Tiejun
2015-07-13 6:47 ` Chen, Tiejun
2015-07-13 8:57 ` Jan Beulich
2015-07-14 10:46 ` George Dunlap
2015-07-14 10:53 ` Chen, Tiejun
2015-07-14 11:30 ` George Dunlap
2015-07-14 11:45 ` Jan Beulich
2015-07-14 13:25 ` George Dunlap
2015-07-09 5:33 ` [v7][PATCH 04/16] xen: enable XENMEM_memory_map in hvm Tiejun Chen
2015-07-09 5:33 ` [v7][PATCH 05/16] hvmloader: get guest memory map into memory_map[] Tiejun Chen
2015-07-10 13:49 ` George Dunlap
2015-07-13 7:03 ` Chen, Tiejun
2015-07-09 5:33 ` [v7][PATCH 06/16] hvmloader/pci: skip reserved ranges Tiejun Chen
2015-07-13 13:12 ` Jan Beulich
2015-07-14 6:39 ` Chen, Tiejun
2015-07-14 9:27 ` Jan Beulich
2015-07-14 10:54 ` Chen, Tiejun
2015-07-14 11:50 ` Jan Beulich
2015-07-15 0:55 ` Chen, Tiejun
2015-07-15 4:27 ` Chen, Tiejun
2015-07-15 8:34 ` Jan Beulich
2015-07-15 8:59 ` Chen, Tiejun
2015-07-15 9:10 ` Chen, Tiejun
2015-07-15 9:27 ` Jan Beulich
2015-07-15 10:34 ` Chen, Tiejun
2015-07-15 11:25 ` Jan Beulich
2015-07-15 11:34 ` Chen, Tiejun
2015-07-15 13:56 ` George Dunlap
2015-07-15 16:14 ` George Dunlap
2015-07-16 2:05 ` Chen, Tiejun
2015-07-16 9:40 ` George Dunlap
2015-07-16 10:01 ` Chen, Tiejun
2015-07-15 11:05 ` George Dunlap
2015-07-15 11:20 ` Chen, Tiejun
2015-07-15 12:43 ` George Dunlap
2015-07-15 13:23 ` Chen, Tiejun
2015-07-15 11:24 ` Jan Beulich
2015-07-15 11:38 ` George Dunlap
2015-07-15 11:27 ` Jan Beulich
2015-07-15 11:40 ` Chen, Tiejun
2015-07-15 8:32 ` Jan Beulich
2015-07-15 9:04 ` Chen, Tiejun
2015-07-15 12:57 ` Wei Liu
2015-07-15 13:40 ` George Dunlap
2015-07-15 14:00 ` Jan Beulich [this message]
2015-07-15 15:19 ` George Dunlap
2015-07-09 5:33 ` [v7][PATCH 07/16] hvmloader/e820: construct guest e820 table Tiejun Chen
2015-07-13 13:35 ` Jan Beulich
2015-07-14 5:22 ` Chen, Tiejun
2015-07-14 9:32 ` Jan Beulich
2015-07-14 10:22 ` Chen, Tiejun
2015-07-14 10:48 ` Jan Beulich
2015-07-15 16:00 ` George Dunlap
2015-07-16 1:58 ` Chen, Tiejun
2015-07-16 9:41 ` George Dunlap
2015-07-09 5:33 ` [v7][PATCH 08/16] tools/libxc: Expose new hypercall xc_reserved_device_memory_map Tiejun Chen
2015-07-09 5:34 ` [v7][PATCH 09/16] tools: extend xc_assign_device() to support rdm reservation policy Tiejun Chen
2015-07-09 5:34 ` [v7][PATCH 10/16] tools: introduce some new parameters to set rdm policy Tiejun Chen
2015-07-09 9:20 ` Wei Liu
2015-07-09 9:44 ` Chen, Tiejun
2015-07-09 10:37 ` Ian Jackson
2015-07-09 10:53 ` Chen, Tiejun
2015-07-09 18:02 ` Ian Jackson
2015-07-10 0:46 ` Chen, Tiejun
2015-07-09 5:34 ` [v7][PATCH 11/16] tools/libxl: detect and avoid conflicts with RDM Tiejun Chen
2015-07-09 9:11 ` Wei Liu
2015-07-09 9:41 ` Chen, Tiejun
2015-07-09 18:14 ` Ian Jackson
2015-07-10 3:19 ` Chen, Tiejun
2015-07-10 10:14 ` Ian Jackson
2015-07-13 9:19 ` Chen, Tiejun
2015-07-09 5:34 ` [v7][PATCH 12/16] tools: introduce a new parameter to set a predefined rdm boundary Tiejun Chen
2015-07-09 18:14 ` Ian Jackson
2015-07-09 5:34 ` [v7][PATCH 13/16] libxl: construct e820 map with RDM information for HVM guest Tiejun Chen
2015-07-09 18:17 ` Ian Jackson
2015-07-10 5:40 ` Chen, Tiejun
2015-07-10 9:18 ` Ian Campbell
2015-07-13 9:47 ` Chen, Tiejun
2015-07-13 10:15 ` Ian Campbell
2015-07-14 5:44 ` Chen, Tiejun
2015-07-14 7:42 ` Ian Campbell
2015-07-14 8:03 ` Chen, Tiejun
2015-07-10 10:15 ` Ian Jackson
2015-07-09 5:34 ` [v7][PATCH 14/16] xen/vtd: enable USB device assignment Tiejun Chen
2015-07-09 5:34 ` [v7][PATCH 15/16] xen/vtd: prevent from assign the device with shared rmrr Tiejun Chen
2015-07-13 13:41 ` Jan Beulich
2015-07-14 1:42 ` Chen, Tiejun
2015-07-14 9:19 ` Jan Beulich
2015-07-09 5:34 ` [v7][PATCH 16/16] tools: parse to enable new rdm policy parameters Tiejun Chen
2015-07-09 18:23 ` Ian Jackson
2015-07-10 6:05 ` Chen, Tiejun
2015-07-10 10:23 ` Ian Jackson
2015-07-13 9:31 ` Chen, Tiejun
2015-07-13 9:40 ` Ian Campbell
2015-07-13 9:55 ` Chen, Tiejun
2015-07-13 10:17 ` Ian Campbell
2015-07-13 17:08 ` Ian Jackson
2015-07-14 1:29 ` Chen, Tiejun
2015-07-10 14:50 ` [v7][PATCH 00/16] Fix RMRR George Dunlap
2015-07-10 14:56 ` Jan Beulich
2015-07-16 7:55 ` Jan Beulich
2015-07-16 8:03 ` Chen, Tiejun
2015-07-16 8:08 ` Jan Beulich
2015-07-16 8:13 ` Chen, Tiejun
2015-07-16 8:26 ` Jan Beulich
2015-07-16 9:27 ` George Dunlap
2015-07-16 9:44 ` Jan Beulich
2015-07-16 9:59 ` George Dunlap
2015-07-16 8:30 ` Ian Campbell
2015-07-16 8:46 ` Wei Liu
2015-07-16 9:45 ` Lars Kurth
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