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>,
Jason Wang <jasowang@redhat.com>,
Oscar Salvador <osalvador@suse.de>,
Igor Mammedov <imammedo@redhat.com>,
Dave Young <dyoung@redhat.com>,
Dan Williams <dan.j.williams@intel.com>,
Pavel Tatashin <pasha.tatashin@soleen.com>,
Stefan Hajnoczi <stefanha@redhat.com>,
Vlastimil Babka <vbabka@suse.cz>
Subject: [PATCH v1 07/11] virtio-mem: Allow to offline partially unplugged memory blocks
Date: Mon, 2 Mar 2020 14:49:37 +0100 [thread overview]
Message-ID: <20200302134941.315212-8-david@redhat.com> (raw)
In-Reply-To: <20200302134941.315212-1-david@redhat.com>
Dropping the reference count of PageOffline() pages allows offlining
code to skip them. However, we also have to convert PG_reserved to
another flag - let's use PG_dirty - so has_unmovable_pages() will
properly handle them. PG_reserved pages get detected as unmovable right
away.
We need the flag to see if we are onlining pages the first time, or if
we allocated them via alloc_contig_range().
Properly take care of offlining code also modifying the stats and
special handling in case the driver gets unloaded.
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Stefan Hajnoczi <stefanha@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: David Hildenbrand <david@redhat.com>
---
drivers/virtio/virtio_mem.c | 64 ++++++++++++++++++++++++++++++++++++-
1 file changed, 63 insertions(+), 1 deletion(-)
diff --git a/drivers/virtio/virtio_mem.c b/drivers/virtio/virtio_mem.c
index 5b26d57be551..2916f8b970fa 100644
--- a/drivers/virtio/virtio_mem.c
+++ b/drivers/virtio/virtio_mem.c
@@ -570,6 +570,53 @@ static void virtio_mem_notify_online(struct virtio_mem *vm, unsigned long mb_id,
virtio_mem_retry(vm);
}
+static void virtio_mem_notify_going_offline(struct virtio_mem *vm,
+ unsigned long mb_id)
+{
+ const unsigned long nr_pages = PFN_DOWN(vm->subblock_size);
+ unsigned long pfn;
+ int sb_id, i;
+
+ for (sb_id = 0; sb_id < vm->nb_sb_per_mb; sb_id++) {
+ if (virtio_mem_mb_test_sb_plugged(vm, mb_id, sb_id, 1))
+ continue;
+ /*
+ * Drop our reference to the pages so the memory can get
+ * offlined and add the unplugged pages to the managed
+ * page counters (so offlining code can correctly subtract
+ * them again).
+ */
+ pfn = PFN_DOWN(virtio_mem_mb_id_to_phys(mb_id) +
+ sb_id * vm->subblock_size);
+ adjust_managed_page_count(pfn_to_page(pfn), nr_pages);
+ for (i = 0; i < nr_pages; i++)
+ page_ref_dec(pfn_to_page(pfn + i));
+ }
+}
+
+static void virtio_mem_notify_cancel_offline(struct virtio_mem *vm,
+ unsigned long mb_id)
+{
+ const unsigned long nr_pages = PFN_DOWN(vm->subblock_size);
+ unsigned long pfn;
+ int sb_id, i;
+
+ for (sb_id = 0; sb_id < vm->nb_sb_per_mb; sb_id++) {
+ if (virtio_mem_mb_test_sb_plugged(vm, mb_id, sb_id, 1))
+ continue;
+ /*
+ * Get the reference we dropped when going offline and
+ * subtract the unplugged pages from the managed page
+ * counters.
+ */
+ pfn = PFN_DOWN(virtio_mem_mb_id_to_phys(mb_id) +
+ sb_id * vm->subblock_size);
+ adjust_managed_page_count(pfn_to_page(pfn), -nr_pages);
+ for (i = 0; i < nr_pages; i++)
+ page_ref_inc(pfn_to_page(pfn + i));
+ }
+}
+
/*
* This callback will either be called synchronously from add_memory() or
* asynchronously (e.g., triggered via user space). We have to be careful
@@ -616,6 +663,7 @@ static int virtio_mem_memory_notifier_cb(struct notifier_block *nb,
break;
}
vm->hotplug_active = true;
+ virtio_mem_notify_going_offline(vm, mb_id);
break;
case MEM_GOING_ONLINE:
mutex_lock(&vm->hotplug_mutex);
@@ -640,6 +688,12 @@ static int virtio_mem_memory_notifier_cb(struct notifier_block *nb,
mutex_unlock(&vm->hotplug_mutex);
break;
case MEM_CANCEL_OFFLINE:
+ if (!vm->hotplug_active)
+ break;
+ virtio_mem_notify_cancel_offline(vm, mb_id);
+ vm->hotplug_active = false;
+ mutex_unlock(&vm->hotplug_mutex);
+ break;
case MEM_CANCEL_ONLINE:
if (!vm->hotplug_active)
break;
@@ -666,8 +720,11 @@ static void virtio_mem_set_fake_offline(unsigned long pfn,
struct page *page = pfn_to_page(pfn);
__SetPageOffline(page);
- if (!onlined)
+ if (!onlined) {
SetPageDirty(page);
+ /* FIXME: remove after cleanups */
+ ClearPageReserved(page);
+ }
}
}
@@ -1717,6 +1774,11 @@ static void virtio_mem_remove(struct virtio_device *vdev)
rc = virtio_mem_mb_remove(vm, mb_id);
BUG_ON(rc);
}
+ /*
+ * After we unregistered our callbacks, user space can no longer
+ * offline partially plugged online memory blocks. No need to worry
+ * about them.
+ */
/* unregister callbacks */
unregister_virtio_mem_device(vm);
--
2.24.1
next prev parent reply other threads:[~2020-03-02 13:52 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-02 13:49 [PATCH v1 00/11] virtio-mem: paravirtualized memory David Hildenbrand
2020-03-02 13:49 ` [PATCH v1 01/11] ACPI: NUMA: export pxm_to_node David Hildenbrand
2020-03-02 14:03 ` Michal Hocko
2020-03-02 14:09 ` David Hildenbrand
2020-03-02 13:49 ` [PATCH v1 02/11] virtio-mem: Paravirtualized memory hotplug David Hildenbrand
2020-03-03 2:24 ` kbuild test robot
2020-03-03 8:06 ` David Hildenbrand
2020-03-02 13:49 ` [PATCH v1 03/11] virtio-mem: Paravirtualized memory hotunplug part 1 David Hildenbrand
2020-03-02 13:49 ` [PATCH v1 04/11] mm: Export alloc_contig_range() / free_contig_range() David Hildenbrand
2020-03-02 14:05 ` Michal Hocko
2020-03-02 14:17 ` David Hildenbrand
2020-03-02 13:49 ` [PATCH v1 05/11] virtio-mem: Paravirtualized memory hotunplug part 2 David Hildenbrand
2020-03-02 13:49 ` [PATCH v1 06/11] mm: Allow to offline unmovable PageOffline() pages via MEM_GOING_OFFLINE David Hildenbrand
2020-03-02 17:40 ` Alexander Duyck
2020-03-02 18:41 ` David Hildenbrand
2020-03-10 11:47 ` Michal Hocko
2020-03-10 11:48 ` David Hildenbrand
2020-03-02 13:49 ` David Hildenbrand [this message]
2020-03-10 11:43 ` [PATCH v1 07/11] virtio-mem: Allow to offline partially unplugged memory blocks Michal Hocko
2020-03-10 11:46 ` David Hildenbrand
2020-03-10 11:59 ` Michal Hocko
2020-03-10 12:09 ` David Hildenbrand
2020-03-02 13:49 ` [PATCH v1 08/11] mm/memory_hotplug: Introduce offline_and_remove_memory() David Hildenbrand
2020-03-02 14:27 ` Michal Hocko
2020-03-02 13:49 ` [PATCH v1 09/11] virtio-mem: Offline and remove completely unplugged memory blocks David Hildenbrand
2020-03-02 13:49 ` [PATCH v1 10/11] virtio-mem: Better retry handling David Hildenbrand
2020-03-02 13:49 ` [PATCH v1 11/11] MAINTAINERS: Add myself as virtio-mem maintainer David Hildenbrand
2020-03-02 18:15 ` [PATCH v1 00/11] virtio-mem: paravirtualized memory David Hildenbrand
2020-03-02 18:29 ` Michal Hocko
2020-03-02 18:41 ` David Hildenbrand
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