From: David Hildenbrand <david@redhat.com>
To: linux-kernel@vger.kernel.org
Cc: virtualization@lists.linux-foundation.org, linux-mm@kvack.org,
"Michael S . Tsirkin" <mst@redhat.com>,
David Hildenbrand <david@redhat.com>,
Jason Wang <jasowang@redhat.com>,
Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Subject: [PATCH v2 10/29] virtio-mem: retry fake-offlining via alloc_contig_range() on ZONE_MOVABLE
Date: Thu, 12 Nov 2020 14:37:56 +0100 [thread overview]
Message-ID: <20201112133815.13332-11-david@redhat.com> (raw)
In-Reply-To: <20201112133815.13332-1-david@redhat.com>
ZONE_MOVABLE is supposed to give some guarantees, yet,
alloc_contig_range() isn't prepared to properly deal with some racy
cases properly (e.g., temporary page pinning when exiting processed, PCP).
Retry 5 times for now. There is certainly room for improvement in the
future.
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
---
drivers/virtio/virtio_mem.c | 37 ++++++++++++++++++++++++++-----------
1 file changed, 26 insertions(+), 11 deletions(-)
diff --git a/drivers/virtio/virtio_mem.c b/drivers/virtio/virtio_mem.c
index c24055248f9d..2f1ce4d4781b 100644
--- a/drivers/virtio/virtio_mem.c
+++ b/drivers/virtio/virtio_mem.c
@@ -784,19 +784,34 @@ static void virtio_mem_fake_online(unsigned long pfn, unsigned long nr_pages)
*/
static int virtio_mem_fake_offline(unsigned long pfn, unsigned long nr_pages)
{
- int rc;
+ const bool is_movable = zone_idx(page_zone(pfn_to_page(pfn))) ==
+ ZONE_MOVABLE;
+ int rc, retry_count;
- rc = alloc_contig_range(pfn, pfn + nr_pages, MIGRATE_MOVABLE,
- GFP_KERNEL);
- if (rc == -ENOMEM)
- /* whoops, out of memory */
- return rc;
- if (rc)
- return -EBUSY;
+ /*
+ * TODO: We want an alloc_contig_range() mode that tries to allocate
+ * harder (e.g., dealing with temporarily pinned pages, PCP), especially
+ * with ZONE_MOVABLE. So for now, retry a couple of times with
+ * ZONE_MOVABLE before giving up - because that zone is supposed to give
+ * some guarantees.
+ */
+ for (retry_count = 0; retry_count < 5; retry_count++) {
+ rc = alloc_contig_range(pfn, pfn + nr_pages, MIGRATE_MOVABLE,
+ GFP_KERNEL);
+ if (rc == -ENOMEM)
+ /* whoops, out of memory */
+ return rc;
+ else if (rc && !is_movable)
+ break;
+ else if (rc)
+ continue;
- virtio_mem_set_fake_offline(pfn, nr_pages, true);
- adjust_managed_page_count(pfn_to_page(pfn), -nr_pages);
- return 0;
+ virtio_mem_set_fake_offline(pfn, nr_pages, true);
+ adjust_managed_page_count(pfn_to_page(pfn), -nr_pages);
+ return 0;
+ }
+
+ return -EBUSY;
}
/*
--
2.26.2
next prev parent reply other threads:[~2020-11-12 13:40 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-12 13:37 [PATCH v2 00/29] virtio-mem: Big Block Mode (BBM) David Hildenbrand
2020-11-12 13:37 ` [PATCH v2 01/29] virtio-mem: determine nid only once using memory_add_physaddr_to_nid() David Hildenbrand
2020-11-12 13:37 ` [PATCH v2 02/29] virtio-mem: more precise calculation in virtio_mem_mb_state_prepare_next_mb() David Hildenbrand
2020-11-12 13:37 ` [PATCH v2 03/29] virtio-mem: simplify MAX_ORDER - 1 / pageblock_order handling David Hildenbrand
2020-11-12 13:37 ` [PATCH v2 04/29] virtio-mem: drop rc2 in virtio_mem_mb_plug_and_add() David Hildenbrand
2020-11-12 13:37 ` [PATCH v2 05/29] virtio-mem: use "unsigned long" for nr_pages when fake onlining/offlining David Hildenbrand
2020-11-12 13:37 ` [PATCH v2 06/29] virtio-mem: factor out calculation of the bit number within the subblock bitmap David Hildenbrand
2020-11-12 13:37 ` [PATCH v2 07/29] virtio-mem: print debug messages from virtio_mem_send_*_request() David Hildenbrand
2020-11-12 13:37 ` [PATCH v2 08/29] virtio-mem: factor out fake-offlining into virtio_mem_fake_offline() David Hildenbrand
2020-11-12 13:37 ` [PATCH v2 09/29] virtio-mem: factor out handling of fake-offline pages in memory notifier David Hildenbrand
2020-11-12 13:37 ` David Hildenbrand [this message]
2020-11-12 13:37 ` [PATCH v2 11/29] virtio-mem: generalize check for added memory David Hildenbrand
2020-11-12 13:37 ` [PATCH v2 12/29] virtio-mem: generalize virtio_mem_owned_mb() David Hildenbrand
2020-11-12 13:37 ` [PATCH v2 13/29] virtio-mem: generalize virtio_mem_overlaps_range() David Hildenbrand
2020-11-12 13:38 ` [PATCH v2 14/29] virtio-mem: drop last_mb_id David Hildenbrand
2020-11-12 13:38 ` [PATCH v2 15/29] virtio-mem: don't always trigger the workqueue when offlining memory David Hildenbrand
2020-11-12 13:38 ` [PATCH v2 16/29] virtio-mem: generalize handling when memory is getting onlined deferred David Hildenbrand
2020-11-12 13:38 ` [PATCH v2 17/29] virito-mem: document Sub Block Mode (SBM) David Hildenbrand
2020-11-12 13:38 ` [PATCH v2 18/29] virtio-mem: memory block states are specific to " David Hildenbrand
2020-11-12 13:38 ` [PATCH v2 19/29] virito-mem: subblock " David Hildenbrand
2020-11-12 13:38 ` [PATCH v2 20/29] virtio-mem: nb_sb_per_mb and subblock_size " David Hildenbrand
2020-11-12 13:38 ` [PATCH v2 21/29] virtio-mem: memory block ids " David Hildenbrand
2020-11-12 13:38 ` [PATCH v2 22/29] virito-mem: existing (un)plug functions " David Hildenbrand
2020-11-12 13:38 ` [PATCH v2 23/29] virtio-mem: memory notifier callbacks " David Hildenbrand
2020-11-12 13:38 ` [PATCH v2 24/29] virtio-mem: factor out adding/removing memory from Linux David Hildenbrand
2020-11-12 13:38 ` [PATCH v2 25/29] virtio-mem: Big Block Mode (BBM) memory hotplug David Hildenbrand
2020-11-12 13:38 ` [PATCH v2 26/29] virtio-mem: allow to force Big Block Mode (BBM) and set the big block size David Hildenbrand
2020-11-12 13:38 ` [PATCH v2 27/29] mm/memory_hotplug: extend offline_and_remove_memory() to handle more than one memory block David Hildenbrand
2020-11-18 4:53 ` Andrew Morton
2020-11-18 8:59 ` David Hildenbrand
2020-11-12 13:38 ` [PATCH v2 28/29] virtio-mem: Big Block Mode (BBM) - basic memory hotunplug David Hildenbrand
2020-11-12 13:38 ` [PATCH v2 29/29] virtio-mem: Big Block Mode (BBM) - safe " David Hildenbrand
2020-11-18 9:00 ` [PATCH v2 00/29] virtio-mem: Big Block Mode (BBM) Michael S. Tsirkin
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