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From: David Hildenbrand <david@redhat.com>
To: qemu-devel@nongnu.org
Cc: "Michael S . Tsirkin" <mst@redhat.com>,
	Michal Privoznik <mprivozn@redhat.com>,
	David Hildenbrand <david@redhat.com>,
	Markus Armbruster <armbru@redhat.com>,
	"Dr. David Alan Gilbert" <dgilbert@redhat.com>,
	Igor Mammedov <imammedo@redhat.com>,
	Eric Blake <eblake@redhat.com>
Subject: [PATCH v3 3/3] monitor: Rate-limit MEMORY_DEVICE_SIZE_CHANGE qapi events per device
Date: Wed, 29 Sep 2021 18:24:45 +0200	[thread overview]
Message-ID: <20210929162445.64060-4-david@redhat.com> (raw)
In-Reply-To: <20210929162445.64060-1-david@redhat.com>

We want to rate-limit MEMORY_DEVICE_SIZE_CHANGE events per device,
otherwise we can lose some events for devices. We can now use the
qom-path to reliably map an event to a device and make rate-limiting
device-aware.

This was noticed by starting a VM with two virtio-mem devices that each
have a requested size > 0. The Linux guest will initialize both devices
in parallel, resulting in losing MEMORY_DEVICE_SIZE_CHANGE events for
one of the devices.

Fixes: 722a3c783ef4 ("virtio-pci: Send qapi events when the virtio-mem size changes")
Suggested-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
---
 monitor/monitor.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/monitor/monitor.c b/monitor/monitor.c
index 46a171bca6..21c7a68758 100644
--- a/monitor/monitor.c
+++ b/monitor/monitor.c
@@ -474,6 +474,10 @@ static unsigned int qapi_event_throttle_hash(const void *key)
         hash += g_str_hash(qdict_get_str(evstate->data, "node-name"));
     }
 
+    if (evstate->event == QAPI_EVENT_MEMORY_DEVICE_SIZE_CHANGE) {
+        hash += g_str_hash(qdict_get_str(evstate->data, "qom-path"));
+    }
+
     return hash;
 }
 
@@ -496,6 +500,11 @@ static gboolean qapi_event_throttle_equal(const void *a, const void *b)
                        qdict_get_str(evb->data, "node-name"));
     }
 
+    if (eva->event == QAPI_EVENT_MEMORY_DEVICE_SIZE_CHANGE) {
+        return !strcmp(qdict_get_str(eva->data, "qom-path"),
+                       qdict_get_str(evb->data, "qom-path"));
+    }
+
     return TRUE;
 }
 
-- 
2.31.1



  parent reply	other threads:[~2021-09-29 16:29 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-29 16:24 [PATCH v3 0/3] " David Hildenbrand
2021-09-29 16:24 ` [PATCH v3 1/3] virtio-mem-pci: Fix memory leak when creating MEMORY_DEVICE_SIZE_CHANGE event David Hildenbrand
2021-09-29 16:24 ` [PATCH v3 2/3] qapi: Include qom-path in MEMORY_DEVICE_SIZE_CHANGE qapi events David Hildenbrand
2021-09-29 16:24 ` David Hildenbrand [this message]
2021-09-30  6:06 ` [PATCH v3 0/3] monitor: Rate-limit MEMORY_DEVICE_SIZE_CHANGE qapi events per device Markus Armbruster

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