From: David Hildenbrand <david@redhat.com>
To: Anshuman Khandual <anshuman.khandual@arm.com>,
linux-mm@kvack.org, akpm@linux-foundation.org, hca@linux.ibm.com,
catalin.marinas@arm.com
Cc: Oscar Salvador <osalvador@suse.de>,
Vasily Gorbik <gor@linux.ibm.com>, Will Deacon <will@kernel.org>,
Ard Biesheuvel <ardb@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
linux-arm-kernel@lists.infradead.org, linux-s390@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH V3 1/3] mm/memory_hotplug: Prevalidate the address range being added with platform
Date: Wed, 20 Jan 2021 11:41:53 +0100 [thread overview]
Message-ID: <30bbf862-06a4-bd1d-b902-61aa4183b819@redhat.com> (raw)
In-Reply-To: <3d4f3b14-0715-b2b3-b015-04b8a77abfb8@arm.com>
On 20.01.21 09:33, Anshuman Khandual wrote:
>
>
> On 1/19/21 5:51 PM, David Hildenbrand wrote:
>> On 18.01.21 14:12, Anshuman Khandual wrote:
>>> This introduces memhp_range_allowed() which can be called in various memory
>>> hotplug paths to prevalidate the address range which is being added, with
>>> the platform. Then memhp_range_allowed() calls memhp_get_pluggable_range()
>>> which provides applicable address range depending on whether linear mapping
>>> is required or not. For ranges that require linear mapping, it calls a new
>>> arch callback arch_get_mappable_range() which the platform can override. So
>>> the new callback, in turn provides the platform an opportunity to configure
>>> acceptable memory hotplug address ranges in case there are constraints.
>>>
>>> This mechanism will help prevent platform specific errors deep down during
>>> hotplug calls. This drops now redundant check_hotplug_memory_addressable()
>>> check in __add_pages() but instead adds a VM_BUG_ON() check which would
>>
>> In this patch, you keep the __add_pages() checks. But as discussed, we
>> could perform it in mm/memremap.c:pagemap_range() insted and convert it
>> to a VM_BUG_ON().
>
> Just to be sure, will the following change achieve what you are
> suggesting here. pagemap_range() after this change, will again
> be the same like the V1 series.
Yeah, as we used to have in v1. Maybe other reviewers (@Oscar?) have a
different opinion.
If you decide to leave as-is, please fixup the patch description. Thanks!
--
Thanks,
David / dhildenb
next prev parent reply other threads:[~2021-01-20 10:42 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-18 13:12 [PATCH V3 0/3] mm/memory_hotplug: Pre-validate the address range with platform Anshuman Khandual
2021-01-18 13:12 ` [PATCH V3 1/3] mm/memory_hotplug: Prevalidate the address range being added " Anshuman Khandual
2021-01-19 12:21 ` David Hildenbrand
2021-01-20 8:33 ` Anshuman Khandual
2021-01-20 10:41 ` David Hildenbrand [this message]
2021-01-20 11:58 ` Oscar Salvador
2021-01-21 9:23 ` Oscar Salvador
2021-01-22 9:18 ` David Hildenbrand
2021-01-22 10:41 ` Anshuman Khandual
2021-01-22 10:42 ` David Hildenbrand
2021-01-22 10:43 ` David Hildenbrand
2021-01-18 13:13 ` [PATCH V3 2/3] arm64/mm: Define arch_get_mappable_range() Anshuman Khandual
2021-01-19 12:24 ` David Hildenbrand
2021-01-18 13:13 ` [PATCH V3 3/3] s390/mm: " Anshuman Khandual
2021-01-19 12:26 ` David Hildenbrand
2021-01-20 8:28 ` Anshuman Khandual
2021-01-20 10:39 ` David Hildenbrand
2021-01-18 13:13 ` [PATCH RFC] virtio-mem: check against memhp_get_pluggable_range() which memory we can hotplug Anshuman Khandual
2021-01-18 13:21 ` Anshuman Khandual
2021-01-19 12:27 ` David Hildenbrand
2021-01-21 9:57 ` David Hildenbrand
2021-01-22 3:32 ` Anshuman Khandual
2021-01-19 13:33 ` [PATCH V3 0/3] mm/memory_hotplug: Pre-validate the address range with platform David Hildenbrand
2021-01-19 13:40 ` Oscar Salvador
2021-01-20 8:37 ` Anshuman Khandual
2021-01-22 6:04 ` Anshuman Khandual
2021-01-22 8:34 ` David Hildenbrand
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