From: David Hildenbrand <david@redhat.com>
To: Oscar Salvador <osalvador@suse.de>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
Andrew Morton <akpm@linux-foundation.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Dan Williams <dan.j.williams@intel.com>,
Daniel Vetter <daniel.vetter@ffwll.ch>,
Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
Mauro Carvalho Chehab <mchehab+huawei@kernel.org>,
Dave Young <dyoung@redhat.com>, Baoquan He <bhe@redhat.com>,
Vivek Goyal <vgoyal@redhat.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
Keith Busch <keith.busch@intel.com>,
Michal Hocko <mhocko@suse.com>, Qian Cai <cai@lca.pw>,
Eric Biederman <ebiederm@xmission.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
"H. Peter Anvin" <hpa@zytor.com>,
Tom Lendacky <thomas.lendacky@amd.com>,
Brijesh Singh <brijesh.singh@amd.com>,
x86@kernel.org, kexec@lists.infradead.org
Subject: Re: [PATCH v1 1/3] kernel/resource: make walk_system_ram_res() find all busy IORESOURCE_SYSTEM_RAM resources
Date: Wed, 24 Mar 2021 12:28:21 +0100 [thread overview]
Message-ID: <8aa6af09-6f8b-1f50-820f-90eab0993f1c@redhat.com> (raw)
In-Reply-To: <20210324111835.GA18855@linux>
On 24.03.21 12:18, Oscar Salvador wrote:
> On Mon, Mar 22, 2021 at 05:01:58PM +0100, David Hildenbrand wrote:
>> It used to be true that we can have busy system RAM only on the first level
>> in the resourc tree. However, this is no longer holds for driver-managed
>> system RAM (i.e., added via dax/kmem and virtio-mem), which gets added on
>> lower levels.
>
> Let me ask some rookie questions:
>
> What does "busy" term stand for here?
IORESOURCE_BUSY - here: actually added, not just some reserved range / container.
> Why resources coming from virtio-mem are added at a lower levels?
Some information can be had from ebf71552bb0e690cad523ad175e8c4c89a33c333
commit ebf71552bb0e690cad523ad175e8c4c89a33c333
Author: David Hildenbrand <david@redhat.com>
Date: Thu May 7 16:01:35 2020 +0200
virtio-mem: Add parent resource for all added "System RAM"
Let's add a parent resource, named after the virtio device (inspired by
drivers/dax/kmem.c). This allows user space to identify which memory
belongs to which virtio-mem device.
With this change and two virtio-mem devices:
:/# cat /proc/iomem
00000000-00000fff : Reserved
00001000-0009fbff : System RAM
[...]
140000000-333ffffff : virtio0
140000000-147ffffff : System RAM
148000000-14fffffff : System RAM
150000000-157ffffff : System RAM
[...]
334000000-3033ffffff : virtio1
338000000-33fffffff : System RAM
340000000-347ffffff : System RAM
348000000-34fffffff : System RAM
[...]
For dax/kmem it comes naturally due to the "Persistent Memory" and
device parent resources like:
140000000-33fffffff : Persistent Memory
140000000-1481fffff : namespace0.0
150000000-33fffffff : dax0.0
150000000-33fffffff : System RAM (kmem)
3280000000-32ffffffff : PCI Bus 0000:00
Thanks
--
Thanks,
David / dhildenb
next prev parent reply other threads:[~2021-03-24 11:28 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-22 16:01 [PATCH v1 0/3] kernel/resource: make walk_system_ram_res() and walk_mem_res() search the whole tree David Hildenbrand
2021-03-22 16:01 ` [PATCH v1 1/3] kernel/resource: make walk_system_ram_res() find all busy IORESOURCE_SYSTEM_RAM resources David Hildenbrand
2021-03-22 16:10 ` Dan Williams
2021-03-23 9:40 ` David Hildenbrand
2021-03-23 11:07 ` Andy Shevchenko
2021-03-23 11:06 ` Andy Shevchenko
2021-03-23 11:25 ` David Hildenbrand
2021-03-23 14:33 ` Baoquan He
2021-03-24 11:18 ` Oscar Salvador
2021-03-24 11:28 ` David Hildenbrand [this message]
2021-03-22 16:01 ` [PATCH v1 2/3] kernel/resource: make walk_mem_res() find all busy IORESOURCE_MEM resources David Hildenbrand
2021-03-22 16:11 ` Dan Williams
2021-03-23 11:08 ` Andy Shevchenko
2021-03-23 11:26 ` David Hildenbrand
2021-03-22 16:02 ` [PATCH v1 3/3] kernel/resource: remove first_lvl / siblings_only logic David Hildenbrand
2021-03-22 16:12 ` Dan Williams
2021-03-23 11:11 ` Andy Shevchenko
2021-03-23 11:19 ` David Hildenbrand
2021-03-23 11:05 ` [PATCH v1 0/3] kernel/resource: make walk_system_ram_res() and walk_mem_res() search the whole tree Andy Shevchenko
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