From: David Hildenbrand <david@redhat.com>
To: linux-kernel@vger.kernel.org
Cc: linux-mm@kvack.org, virtualization@lists.linux-foundation.org,
Andrea Arcangeli <aarcange@redhat.com>,
David Hildenbrand <david@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>,
Oscar Salvador <osalvador@suse.com>,
Michal Hocko <mhocko@suse.com>,
Pavel Tatashin <pasha.tatashin@soleen.com>,
Wei Yang <richard.weiyang@gmail.com>,
Dan Williams <dan.j.williams@intel.com>, Qian Cai <cai@lca.pw>
Subject: [PATCH RFC v3 8/9] mm/memory_hotplug: Introduce offline_and_remove_memory()
Date: Thu, 19 Sep 2019 16:22:27 +0200 [thread overview]
Message-ID: <20190919142228.5483-9-david@redhat.com> (raw)
In-Reply-To: <20190919142228.5483-1-david@redhat.com>
virtio-mem wants to offline and remove a memory block once it unplugged
all subblocks (e.g., using alloc_contig_range()). Let's provide
an interface to do that from a driver. virtio-mem already supports to
offline partially unplugged memory blocks. Offlining a fully unplugged
memory block will not require to migrate any pages. All unplugged
subblocks are PageOffline() and have a reference count of 0 - so
offlining code will simply skip them.
All we need an interface to trigger the "offlining" and the removing in a
single operation - to make sure the memory block cannot get onlined by
user space again before it gets removed.
To keep things simple, allow to only work on a single memory block.
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Oscar Salvador <osalvador@suse.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Qian Cai <cai@lca.pw>
Signed-off-by: David Hildenbrand <david@redhat.com>
---
include/linux/memory_hotplug.h | 1 +
mm/memory_hotplug.c | 35 ++++++++++++++++++++++++++++++++++
2 files changed, 36 insertions(+)
diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h
index 384ffb3d69ab..a1bf868aaeba 100644
--- a/include/linux/memory_hotplug.h
+++ b/include/linux/memory_hotplug.h
@@ -313,6 +313,7 @@ extern void try_offline_node(int nid);
extern int offline_pages(unsigned long start_pfn, unsigned long nr_pages);
extern int remove_memory(int nid, u64 start, u64 size);
extern void __remove_memory(int nid, u64 start, u64 size);
+extern int offline_and_remove_memory(int nid, u64 start, u64 size);
#else
static inline bool is_mem_section_removable(unsigned long pfn,
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index d23ff7c5c96b..caf3c93f5f7c 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1742,4 +1742,39 @@ int remove_memory(int nid, u64 start, u64 size)
return rc;
}
EXPORT_SYMBOL_GPL(remove_memory);
+
+/*
+ * Try to offline and remove a memory block. Might take a long time to
+ * finish in case memory is still in use. Primarily useful for memory devices
+ * that logically unplugged all memory (so it's no longer in use) and want to
+ * offline + remove the memory block.
+ */
+int offline_and_remove_memory(int nid, u64 start, u64 size)
+{
+ struct memory_block *mem;
+ int rc = -EINVAL;
+
+ if (!IS_ALIGNED(start, memory_block_size_bytes()) ||
+ size != memory_block_size_bytes())
+ return rc;
+
+ lock_device_hotplug();
+ mem = find_memory_block(__pfn_to_section(PFN_DOWN(start)));
+ if (mem)
+ rc = device_offline(&mem->dev);
+ /* Ignore if the device is already offline. */
+ if (rc > 0)
+ rc = 0;
+
+ /*
+ * In case we succeeded to offline the memory block, remove it.
+ * This cannot fail as it cannot get onlined in the meantime.
+ */
+ if (!rc && try_remove_memory(nid, start, size))
+ BUG();
+ unlock_device_hotplug();
+
+ return rc;
+}
+EXPORT_SYMBOL_GPL(offline_and_remove_memory);
#endif /* CONFIG_MEMORY_HOTREMOVE */
--
2.21.0
next prev parent reply other threads:[~2019-09-19 14:23 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-19 14:22 [PATCH RFC v3 0/9] virtio-mem: paravirtualized memory David Hildenbrand
2019-09-19 14:22 ` [PATCH RFC v3 1/9] ACPI: NUMA: export pxm_to_node David Hildenbrand
2019-09-23 10:13 ` David Hildenbrand
2019-09-23 10:36 ` Michal Hocko
2019-09-23 10:39 ` David Hildenbrand
2019-09-19 14:22 ` [PATCH RFC v3 2/9] virtio-mem: Paravirtualized memory hotplug David Hildenbrand
2019-09-19 14:22 ` [PATCH RFC v3 3/9] virtio-mem: Paravirtualized memory hotunplug part 1 David Hildenbrand
2019-09-19 14:22 ` [PATCH RFC v3 4/9] mm: Export alloc_contig_range() / free_contig_range() David Hildenbrand
2019-10-16 11:20 ` Michal Hocko
2019-10-16 12:31 ` David Hildenbrand
2019-09-19 14:22 ` [PATCH RFC v3 5/9] virtio-mem: Paravirtualized memory hotunplug part 2 David Hildenbrand
2019-09-19 14:22 ` [PATCH RFC v3 6/9] mm: Allow to offline PageOffline() pages with a reference count of 0 David Hildenbrand
2019-10-16 11:43 ` Michal Hocko
2019-10-16 12:50 ` David Hildenbrand
2019-10-16 13:45 ` Michal Hocko
2019-10-16 13:55 ` David Hildenbrand
2019-10-16 14:09 ` Michal Hocko
2019-10-16 14:16 ` David Hildenbrand
2019-10-16 13:59 ` David Hildenbrand
2019-10-16 13:45 ` David Hildenbrand
2019-10-16 14:03 ` Michal Hocko
2019-10-16 14:14 ` David Hildenbrand
2019-10-18 8:15 ` Michal Hocko
2019-10-18 8:50 ` David Hildenbrand
2019-10-18 11:20 ` Michal Hocko
2019-10-18 12:35 ` David Hildenbrand
2019-10-22 12:23 ` Michal Hocko
2019-10-22 14:02 ` David Hildenbrand
2019-10-23 9:43 ` Michal Hocko
2019-10-23 10:03 ` David Hildenbrand
2019-10-24 8:42 ` Michal Hocko
2019-10-24 8:51 ` David Hildenbrand
2019-10-25 11:28 ` [PATCH RFC] mm: Allow to offline unmovable PageOffline() pages if the driver agrees David Hildenbrand
2019-09-19 14:22 ` [PATCH RFC v3 7/9] virtio-mem: Allow to offline partially unplugged memory blocks David Hildenbrand
2019-09-19 14:22 ` David Hildenbrand [this message]
2019-10-16 11:47 ` [PATCH RFC v3 8/9] mm/memory_hotplug: Introduce offline_and_remove_memory() Michal Hocko
2019-10-16 12:57 ` David Hildenbrand
2019-09-19 14:22 ` [PATCH RFC v3 9/9] virtio-mem: Offline and remove completely unplugged memory blocks David Hildenbrand
2019-10-16 8:12 ` [PATCH RFC v3 0/9] virtio-mem: paravirtualized memory David Hildenbrand
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