From: Vlastimil Babka <vbabka@suse.cz>
To: Matthew Wilcox <willy@infradead.org>,
David Hildenbrand <david@redhat.com>
Cc: linux-mm@kvack.org, Steven Rostedt <rostedt@goodmis.org>,
Ingo Molnar <mingo@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>,
Michal Hocko <mhocko@suse.com>, Huang Ying <ying.huang@intel.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Pavel Tatashin <pasha.tatashin@oracle.com>,
Miles Chen <miles.chen@mediatek.com>,
Mel Gorman <mgorman@techsingularity.net>,
Rik van Riel <riel@redhat.com>, James Hogan <jhogan@kernel.org>,
"Levin, Alexander (Sasha Levin)" <alexander.levin@verizon.com>,
open list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH RFC 2/8] mm: introduce PG_offline
Date: Sat, 21 Apr 2018 18:52:18 +0200 [thread overview]
Message-ID: <89329958-2ff8-9447-408e-fd478b914ec4@suse.cz> (raw)
In-Reply-To: <20180413171120.GA1245@bombadil.infradead.org>
On 04/13/2018 07:11 PM, Matthew Wilcox wrote:
> On Fri, Apr 13, 2018 at 03:16:26PM +0200, David Hildenbrand wrote:
>> online_pages()/offline_pages() theoretically allows us to work on
>> sub-section sizes. This is especially relevant in the context of
>> virtualization. It e.g. allows us to add/remove memory to Linux in a VM in
>> 4MB chunks.
>>
>> While the whole section is marked as online/offline, we have to know
>> the state of each page. E.g. to not read memory that is not online
>> during kexec() or to properly mark a section as offline as soon as all
>> contained pages are offline.
>
> Can you not use PG_reserved for this purpose?
Sounds like your newly introduced "page types" could be useful here? I
don't suppose those offline pages would be using mapcount which is
aliased there?
>> + * PG_offline indicates that a page is offline and the backing storage
>> + * might already have been removed (virtualization). Don't touch!
>
> * PG_reserved is set for special pages, which can never be swapped out. Some
> * of them might not even exist...
>
> They seem pretty congruent to me.
>
next prev parent reply other threads:[~2018-04-21 16:52 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-04-13 13:16 [PATCH RFC 0/8] mm: online/offline 4MB chunks controlled by device driver David Hildenbrand
2018-04-13 13:16 ` [PATCH RFC 1/8] mm/memory_hotplug: Revert "mm/memory_hotplug: optimize memory hotplug" David Hildenbrand
2018-04-13 13:16 ` David Hildenbrand
2018-04-13 13:16 ` [PATCH RFC 2/8] mm: introduce PG_offline David Hildenbrand
2018-04-13 13:16 ` David Hildenbrand
2018-04-13 13:40 ` Michal Hocko
2018-04-13 13:46 ` David Hildenbrand
2018-04-17 11:50 ` David Hildenbrand
2018-04-13 17:11 ` Matthew Wilcox
2018-04-16 8:31 ` David Hildenbrand
2018-04-21 16:52 ` Vlastimil Babka [this message]
2018-04-22 3:01 ` Matthew Wilcox
2018-04-22 8:17 ` David Hildenbrand
2018-04-22 14:02 ` Matthew Wilcox
2018-04-22 15:13 ` David Hildenbrand
2018-04-29 21:08 ` Michal Hocko
2018-04-30 6:31 ` David Hildenbrand
2018-04-20 7:30 ` David Hildenbrand
2018-04-13 13:16 ` [PATCH RFC 3/8] mm: use PG_offline in online/offlining code David Hildenbrand
2018-04-13 13:16 ` David Hildenbrand
2018-04-13 13:31 ` [PATCH RFC 4/8] kdump: expose PG_offline David Hildenbrand
2018-04-13 13:33 ` [PATCH RFC 5/8] mm: only mark section offline when all pages are offline David Hildenbrand
2018-04-13 13:33 ` David Hildenbrand
2018-04-13 13:33 ` [PATCH RFC 6/8] mm: offline_pages() is also limited by MAX_ORDER David Hildenbrand
2018-04-13 13:33 ` David Hildenbrand
2018-04-13 13:33 ` [PATCH RFC 7/8] mm: allow to control onlining/offlining of memory by a driver David Hildenbrand
2018-04-13 13:33 ` David Hildenbrand
2018-04-13 13:33 ` David Hildenbrand
2018-04-13 15:59 ` Michal Hocko
2018-04-13 15:59 ` Michal Hocko
2018-04-13 16:32 ` David Hildenbrand
2018-04-13 16:32 ` David Hildenbrand
2018-04-13 13:33 ` [PATCH RFC 8/8] mm: export more functions used to online/offline memory David Hildenbrand
2018-04-13 13:33 ` David Hildenbrand
2018-04-13 13:44 ` [PATCH RFC 0/8] mm: online/offline 4MB chunks controlled by device driver Michal Hocko
2018-04-13 14:01 ` David Hildenbrand
2018-04-13 14:20 ` Michal Hocko
2018-04-13 14:59 ` David Hildenbrand
2018-04-13 15:02 ` David Hildenbrand
2018-04-13 16:03 ` Michal Hocko
2018-04-13 16:36 ` David Hildenbrand
2018-04-13 15:59 ` Michal Hocko
2018-04-13 16:31 ` David Hildenbrand
2018-04-16 14:08 ` Michal Hocko
2018-04-16 14:48 ` David Hildenbrand
2018-04-18 15:46 ` David Hildenbrand
2018-04-19 7:33 ` Michal Hocko
2018-04-26 15:30 ` David Hildenbrand
2018-04-29 21:05 ` Michal Hocko
2018-04-30 6:24 ` David Hildenbrand
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