Discussion of the implementations of VIRTIO specification
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From: Wei Wang <wei.w.wang@intel.com>
To: virtio-dev@lists.oasis-open.org, linux-kernel@vger.kernel.org,
	virtualization@lists.linux-foundation.org, kvm@vger.kernel.org,
	mst@redhat.com, cohuck@redhat.com
Cc: borntraeger@de.ibm.com, pbonzini@redhat.com, dgilbert@redhat.com,
	wei.w.wang@intel.com, pasic@linux.ibm.com
Subject: [virtio-dev] [PATCH v1 2/2] virtio-balloon: improve update_balloon_size_func
Date: Thu,  3 Jan 2019 13:31:02 +0800	[thread overview]
Message-ID: <1546493462-32244-3-git-send-email-wei.w.wang@intel.com> (raw)
In-Reply-To: <1546493462-32244-1-git-send-email-wei.w.wang@intel.com>

There is no need to update the balloon actual register when there is no
ballooning request. This patch avoids update_balloon_size when diff is 0.

Signed-off-by: Wei Wang <wei.w.wang@intel.com>
---
 drivers/virtio/virtio_balloon.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
index 9a82a11..4884b85 100644
--- a/drivers/virtio/virtio_balloon.c
+++ b/drivers/virtio/virtio_balloon.c
@@ -435,9 +435,12 @@ static void update_balloon_size_func(struct work_struct *work)
 			  update_balloon_size_work);
 	diff = towards_target(vb);
 
+	if (!diff)
+		return;
+
 	if (diff > 0)
 		diff -= fill_balloon(vb, diff);
-	else if (diff < 0)
+	else
 		diff += leak_balloon(vb, -diff);
 	update_balloon_size(vb);
 
-- 
2.7.4


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  parent reply	other threads:[~2019-01-03  6:06 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-01-03  5:31 [virtio-dev] [PATCH v1 0/2] virtio-balloon: tweak config_changed Wei Wang
2019-01-03  5:31 ` [virtio-dev] [PATCH v1 1/2] virtio-balloon: tweak config_changed implementation Wei Wang
2019-01-03  9:40   ` [virtio-dev] " Cornelia Huck
2019-01-03 10:31     ` Wei Wang
2019-01-03 12:16   ` Halil Pasic
2019-01-03 16:42   ` Michael S. Tsirkin
2019-01-04  5:14     ` Wei Wang
2019-01-03  5:31 ` Wei Wang [this message]
2019-01-03  9:42   ` [virtio-dev] Re: [PATCH v1 2/2] virtio-balloon: improve update_balloon_size_func Cornelia Huck
2019-01-03 12:18   ` Halil Pasic
2019-01-03  9:26 ` [virtio-dev] Re: [PATCH v1 0/2] virtio-balloon: tweak config_changed Cornelia Huck

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