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authorPaolo Abeni <pabeni@redhat.com>2018-11-21 18:21:35 +0100
committerDavid S. Miller <davem@davemloft.net>2018-11-23 11:18:53 -0800
commit605108acfe6233b72e2f803aa1cb59a2af3001ca (patch)
tree7176a1fdfdd38c73fcf4d40ed76db3dcfc337b9e /net
parent896585d48e8e9ba44cd1754fbce8537feffcc1a5 (diff)
downloadlinux-605108acfe6233b72e2f803aa1cb59a2af3001ca.tar.bz2
net: don't keep lonely packets forever in the gro hash
Eric noted that with UDP GRO and NAPI timeout, we could keep a single UDP packet inside the GRO hash forever, if the related NAPI instance calls napi_gro_complete() at an higher frequency than the NAPI timeout. Willem noted that even TCP packets could be trapped there, till the next retransmission. This patch tries to address the issue, flushing the old packets - those with a NAPI_GRO_CB age before the current jiffy - before scheduling the NAPI timeout. The rationale is that such a timeout should be well below a jiffy and we are not flushing packets eligible for sane GRO. v1 -> v2: - clarified the commit message and comment RFC -> v1: - added 'Fixes tags', cleaned-up the wording. Reported-by: Eric Dumazet <eric.dumazet@gmail.com> Fixes: 3b47d30396ba ("net: gro: add a per device gro flush timer") Signed-off-by: Paolo Abeni <pabeni@redhat.com> Acked-by: Willem de Bruijn <willemb@google.com> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/core/dev.c7
1 files changed, 5 insertions, 2 deletions
diff --git a/net/core/dev.c b/net/core/dev.c
index 066aa902d85c..ddc551f24ba2 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -5970,11 +5970,14 @@ bool napi_complete_done(struct napi_struct *n, int work_done)
if (work_done)
timeout = n->dev->gro_flush_timeout;
+ /* When the NAPI instance uses a timeout and keeps postponing
+ * it, we need to bound somehow the time packets are kept in
+ * the GRO layer
+ */
+ napi_gro_flush(n, !!timeout);
if (timeout)
hrtimer_start(&n->timer, ns_to_ktime(timeout),
HRTIMER_MODE_REL_PINNED);
- else
- napi_gro_flush(n, false);
}
if (unlikely(!list_empty(&n->poll_list))) {
/* If n->poll_list is not empty, we need to mask irqs */