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From: David Hildenbrand <david@redhat.com>
To: linux-kernel@vger.kernel.org
Cc: linux-mm@kvack.org, virtio-dev@lists.oasis-open.org,
	virtualization@lists.linux-foundation.org, kvm@vger.kernel.org,
	Michal Hocko <mhocko@kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	"Michael S . Tsirkin" <mst@redhat.com>,
	David Hildenbrand <david@redhat.com>,
	Michal Hocko <mhocko@suse.com>, Vlastimil Babka <vbabka@suse.cz>,
	Oscar Salvador <osalvador@suse.de>,
	Mel Gorman <mgorman@techsingularity.net>,
	Mike Rapoport <rppt@linux.ibm.com>,
	Dan Williams <dan.j.williams@intel.com>,
	Alexander Duyck <alexander.h.duyck@linux.intel.com>,
	Pavel Tatashin <pavel.tatashin@microsoft.com>,
	Alexander Potapenko <glider@google.com>
Subject: [PATCH RFC v4 04/13] mm: Export alloc_contig_range() / free_contig_range()
Date: Thu, 12 Dec 2019 18:11:28 +0100	[thread overview]
Message-ID: <20191212171137.13872-5-david@redhat.com> (raw)
In-Reply-To: <20191212171137.13872-1-david@redhat.com>

A virtio-mem device wants to allocate memory from the memory region it
manages in order to unplug it in the hypervisor - similar to
a balloon driver. Also, it might want to plug previously unplugged
(allocated) memory and give it back to Linux. alloc_contig_range() /
free_contig_range() seem to be the perfect interface for this task.

In contrast to existing balloon devices, a virtio-mem device operates
on bigger chunks (e.g., 4MB) and only on physical memory it manages. It
tracks which chunks (subblocks) are still plugged, so it can go ahead
and try to alloc_contig_range()+unplug them on unplug request, or
plug+free_contig_range() unplugged chunks on plug requests.

A virtio-mem device will use alloc_contig_range() / free_contig_range()
only on ranges that belong to the same node/zone in at least
MAX(MAX_ORDER - 1, pageblock_order) order granularity - e.g., 4MB on
x86-64. The virtio-mem device added that memory, so the memory
exists and does not contain any holes. virtio-mem will only try to allocate
on ZONE_NORMAL, never on ZONE_MOVABLE, just like when allocating
gigantic pages (we don't put unmovable data into the movable zone).

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Cc: Pavel Tatashin <pavel.tatashin@microsoft.com>
Cc: Alexander Potapenko <glider@google.com>
Acked-by: Michal Hocko <mhocko@suse.com> # to export contig range allocator API
Signed-off-by: David Hildenbrand <david@redhat.com>
---
 mm/page_alloc.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 62dcd6b76c80..5334decc9e06 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -8494,6 +8494,7 @@ int alloc_contig_range(unsigned long start, unsigned long end,
 				pfn_max_align_up(end), migratetype);
 	return ret;
 }
+EXPORT_SYMBOL(alloc_contig_range);
 
 static int __alloc_contig_pages(unsigned long start_pfn,
 				unsigned long nr_pages, gfp_t gfp_mask)
@@ -8609,6 +8610,7 @@ void free_contig_range(unsigned long pfn, unsigned int nr_pages)
 	}
 	WARN(count != 0, "%d pages are still in use!\n", count);
 }
+EXPORT_SYMBOL(free_contig_range);
 
 /*
  * The zone indicated has a new number of managed_pages; batch sizes and percpu
-- 
2.23.0


  parent reply	other threads:[~2019-12-12 17:12 UTC|newest]

Thread overview: 47+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-12 17:11 [PATCH RFC v4 00/13] virtio-mem: paravirtualized memory David Hildenbrand
2019-12-12 17:11 ` [PATCH RFC v4 01/13] ACPI: NUMA: export pxm_to_node David Hildenbrand
2019-12-12 21:43   ` Rafael J. Wysocki
2019-12-13  9:41     ` David Hildenbrand
2019-12-13  9:47       ` Rafael J. Wysocki
2019-12-12 17:11 ` [PATCH RFC v4 02/13] virtio-mem: Paravirtualized memory hotplug David Hildenbrand
2019-12-12 17:11 ` [PATCH RFC v4 03/13] virtio-mem: Paravirtualized memory hotunplug part 1 David Hildenbrand
2019-12-12 17:11 ` David Hildenbrand [this message]
2019-12-12 17:11 ` [PATCH RFC v4 05/13] virtio-mem: Paravirtualized memory hotunplug part 2 David Hildenbrand
2019-12-12 17:11 ` [PATCH RFC v4 06/13] mm: Allow to offline unmovable PageOffline() pages via MEM_GOING_OFFLINE David Hildenbrand
2020-02-25 18:26   ` Alexander Duyck
2020-02-25 18:49     ` David Hildenbrand
2020-02-25 21:46       ` Alexander Duyck
2020-02-25 22:19         ` David Hildenbrand
2020-02-26 16:27           ` Alexander Duyck
2019-12-12 17:11 ` [PATCH RFC v4 07/13] virtio-mem: Allow to offline partially unplugged memory blocks David Hildenbrand
2019-12-12 17:11 ` [PATCH RFC v4 08/13] mm/memory_hotplug: Introduce offline_and_remove_memory() David Hildenbrand
2020-02-25 14:11   ` Michal Hocko
2020-02-25 14:27     ` David Hildenbrand
2020-03-02 12:48       ` Michal Hocko
2020-03-02 12:53         ` David Hildenbrand
2019-12-12 17:11 ` [PATCH RFC v4 09/13] virtio-mem: Offline and remove completely unplugged memory blocks David Hildenbrand
2019-12-12 17:11 ` [PATCH RFC v4 10/13] virtio-mem: Better retry handling David Hildenbrand
2019-12-12 17:11 ` [PATCH RFC v4 11/13] mm/vmscan: Move count_vm_event(DROP_SLAB) into drop_slab() David Hildenbrand
2020-02-25 14:13   ` Michal Hocko
2019-12-12 17:11 ` [PATCH RFC v4 12/13] mm/vmscan: Export drop_slab() and drop_slab_node() David Hildenbrand
2020-02-25 14:58   ` Michal Hocko
2020-02-25 15:09     ` David Hildenbrand
2020-02-25 17:06       ` Michal Hocko
2020-02-25 17:23         ` David Hildenbrand
2019-12-12 17:11 ` [PATCH RFC v4 13/13] virtio-mem: Drop slab objects when unplug continues to fail David Hildenbrand
2019-12-13 20:15 ` [PATCH RFC v4 00/13] virtio-mem: paravirtualized memory Konrad Rzeszutek Wilk
2019-12-16 11:03   ` David Hildenbrand
2019-12-24  6:58 ` teawater
2019-12-24  9:28   ` David Hildenbrand
2020-01-09 13:48 ` David Hildenbrand
2020-01-29  9:41   ` David Hildenbrand
2020-02-25  9:58     ` David Hildenbrand
2020-06-05  8:55   ` Alex Shi
2020-06-05  9:08     ` David Hildenbrand
2020-06-05  9:36       ` David Hildenbrand
2020-06-05 10:05         ` David Hildenbrand
2020-06-05 10:46           ` Alex Shi
2020-06-05 12:18             ` David Hildenbrand
2020-06-09  3:05               ` Alex Shi
2020-06-05 10:08         ` Alex Shi
2020-06-05 10:06       ` Alex Shi

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