Re: [dpdk-dev] [PATCH v6 3/7] vhost: fix missing cache logging NUMA realloc

Hi Maxime,

-----Original Message-----
From: Maxime Coquelin <redacted>
Sent: Tuesday, June 29, 2021 10:39 PM
To: Xia, Chenbo <redacted>; dev@dpdk.org;
david.marchand@redhat.com
Subject: Re: [PATCH v6 3/7] vhost: fix missing cache logging NUMA realloc



On 6/25/21 4:50 AM, Xia, Chenbo wrote:

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Hi Maxime,

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-----Original Message-----
From: Maxime Coquelin <redacted>
Sent: Friday, June 18, 2021 10:04 PM
To: dev@dpdk.org; david.marchand@redhat.com; Xia, Chenbo

[off-list ref]

quoted

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Cc: Maxime Coquelin <redacted>
Subject: [PATCH v6 3/7] vhost: fix missing cache logging NUMA realloc

When the guest allocates virtqueues on a different NUMA node
than the one the Vhost metadata are allocated, both the Vhost
device struct and the virtqueues struct are reallocated.

However, reallocating the log cache on the new NUMA node was
not done. This patch fixes this by reallocating it if it has
been allocated already, which means a live-migration is
on-going.

Fixes: 1818a63147fb ("vhost: move dirty logging cache out of virtqueue")

This commit is of 21.05, although LTS maintainers don't maintain non-LTS

stable

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releases now, I guess it's still better to add 'cc stable tag' in case

anyone

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volunteers to do that?

I don't think that's what we do usually.
If someone wants to maintain v21.05 in the future, he can just look for
the Fixes tag in the git history.

Thanks,
Maxime

I asked Thomas and Ferruh this question to make sure we are all aligned. Seems
they think we'd better add it in this case. Thomas's two reasons:

- we don't know in advance whether a branch will be maintained
- it helps those maintaining a private stable branch

And my understanding is adding both fix tag and stable tag makes it clearer for
stable release maintainers (They can just ignore 'only fix tag' case). And anyway
they need to check the fix commit ID.

Anyway, I could add it with some small changes David asked for if you don’t plan
a new version. Do you?

Thanks,
Chenbo

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Thanks,
Chenbo

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Signed-off-by: Maxime Coquelin <redacted>
---
 lib/vhost/vhost_user.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/lib/vhost/vhost_user.c b/lib/vhost/vhost_user.c
index 5fb055ea2e..82adf80fe5 100644
--- a/lib/vhost/vhost_user.c
+++ b/lib/vhost/vhost_user.c

@@ -545,6 +545,16 @@ numa_realloc(struct virtio_net *dev, int index)
 			vq->batch_copy_elems = new_batch_copy_elems;
 		}

+		if (vq->log_cache) {
+			struct log_cache_entry *log_cache;
+
+			log_cache = rte_realloc_socket(vq->log_cache,
+					sizeof(struct log_cache_entry) *

VHOST_LOG_CACHE_NR,
+					0, newnode);
+			if (log_cache)
+				vq->log_cache = log_cache;
+		}
+
 		rte_free(old_vq);
 	}

--
2.31.1