From: David Hildenbrand <david@redhat.com>
To: Oscar Salvador <osalvador@suse.de>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Michal Hocko <mhocko@kernel.org>,
Anshuman Khandual <anshuman.khandual@arm.com>,
Pavel Tatashin <pasha.tatashin@soleen.com>,
Vlastimil Babka <vbabka@suse.cz>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v8 4/8] mm,memory_hotplug: Allocate memmap from the added memory range
Date: Fri, 16 Apr 2021 12:51:31 +0200 [thread overview]
Message-ID: <6e659d5b-c3f1-bd72-a3af-235d6bc55b0b@redhat.com> (raw)
In-Reply-To: <YHlpAvTPuRZtKo0i@localhost.localdomain>
On 16.04.21 12:37, Oscar Salvador wrote:
> On Fri, Apr 16, 2021 at 12:33:34PM +0200, David Hildenbrand wrote:
>> IIRC, we have to add the zero shadow first, before touching the memory. This
>> is also what mm/memremap.c does.
>>
>> In mhp_deinit_memmap_on_memory(), you already remove in the proper
>> (reversed) order :)
>
> But looking at online_pages(), we do it after the
> move_pfn_range_to_zone(), right? AFAIK (I might be well wrong here),
> memory_notify() will eventually call kasan_add_zero_shadow? So that
> comes after the move_pfn_range_to_zone? Or is my understanding
> incorrect?
The thing is: move_pfn_range_to_zone() in case of ordinary
online_pages() won't touch the pages but only the memmap. The memmap has
a proper kasan shadow already. Pages won't be touched before exposing
them to the page allocator via generic_online_pages().
This is different in this case :)
--
Thanks,
David / dhildenb
next prev parent reply other threads:[~2021-04-16 10:51 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-16 10:21 [PATCH v8 0/8] Allocate memmap from hotadded memory (per device) Oscar Salvador
2021-04-16 10:21 ` [PATCH v8 1/8] drivers/base/memory: Introduce memory_block_{online,offline} Oscar Salvador
2021-04-16 10:21 ` [PATCH v8 2/8] mm,memory_hotplug: Relax fully spanned sections check Oscar Salvador
2021-04-16 10:21 ` [PATCH v8 3/8] mm,memory_hotplug: Factor out adjusting present pages into adjust_present_page_count() Oscar Salvador
2021-04-16 10:21 ` [PATCH v8 4/8] mm,memory_hotplug: Allocate memmap from the added memory range Oscar Salvador
2021-04-16 10:33 ` David Hildenbrand
2021-04-16 10:37 ` Oscar Salvador
2021-04-16 10:51 ` David Hildenbrand [this message]
2021-04-16 11:01 ` Oscar Salvador
2021-04-16 11:07 ` David Hildenbrand
2021-04-16 10:21 ` [PATCH v8 5/8] acpi,memhotplug: Enable MHP_MEMMAP_ON_MEMORY when supported Oscar Salvador
2021-04-16 10:21 ` [PATCH v8 6/8] mm,memory_hotplug: Add kernel boot option to enable memmap_on_memory Oscar Salvador
2021-04-16 10:21 ` [PATCH v8 7/8] x86/Kconfig: Introduce ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE Oscar Salvador
2021-04-16 10:21 ` [PATCH v8 8/8] arm64/Kconfig: " Oscar Salvador
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