From: Zoltan Kiss <zoltan.kiss@citrix.com>
To: Wei Liu <wei.liu2@citrix.com>
Cc: <ian.campbell@citrix.com>, <xen-devel@lists.xenproject.org>,
<netdev@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
<jonathan.davies@citrix.com>
Subject: Re: [PATCH net-next v4 6/9] xen-netback: Handle guests with too many frags
Date: Mon, 20 Jan 2014 17:26:40 +0000 [thread overview]
Message-ID: <52DD5C50.7010101@citrix.com> (raw)
In-Reply-To: <20140116000314.GD5331@zion.uk.xensource.com>
On 16/01/14 00:03, Wei Liu wrote:
> On Tue, Jan 14, 2014 at 08:39:52PM +0000, Zoltan Kiss wrote:
> [...]
>> /* Skip first skb fragment if it is on same page as header fragment. */
>> @@ -832,6 +851,29 @@ static struct gnttab_map_grant_ref *xenvif_get_requests(struct xenvif *vif,
>>
>> BUG_ON(shinfo->nr_frags > MAX_SKB_FRAGS);
>>
>> + if (frag_overflow) {
>> + struct sk_buff *nskb = xenvif_alloc_skb(0);
>> + if (unlikely(nskb == NULL)) {
>> + netdev_err(vif->dev,
>> + "Can't allocate the frag_list skb.\n");
>
> This, and other occurences of netdev_* logs need to be rate limit.
> Otherwise you risk flooding kernel log when system is under memory
> pressure.
Done.
>> @@ -1537,6 +1613,32 @@ static int xenvif_tx_submit(struct xenvif *vif)
>> pending_idx :
>> INVALID_PENDING_IDX);
>>
>> + if (skb_shinfo(skb)->frag_list) {
>> + nskb = skb_shinfo(skb)->frag_list;
>> + xenvif_fill_frags(vif, nskb, INVALID_PENDING_IDX);
>> + skb->len += nskb->len;
>> + skb->data_len += nskb->len;
>> + skb->truesize += nskb->truesize;
>> + skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
>> + skb_shinfo(nskb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
>> + vif->tx_zerocopy_sent += 2;
>> + nskb = skb;
>> +
>> + skb = skb_copy_expand(skb,
>> + 0,
>> + 0,
>> + GFP_ATOMIC | __GFP_NOWARN);
>> + if (!skb) {
>> + netdev_dbg(vif->dev,
>> + "Can't consolidate skb with too many fragments\n");
>
> Rate limit.
>
>> + if (skb_shinfo(nskb)->destructor_arg)
>> + skb_shinfo(nskb)->tx_flags |=
>> + SKBTX_DEV_ZEROCOPY;
>
> Why is this needed? nskb is the saved pointer to original skb, which has
> already had SKBTX_DEV_ZEROCOPY in tx_flags. Did I miss something?
Indeed. This actually belongs to the header grant copy patches I've sent
in as well. I move it there.
next prev parent reply other threads:[~2014-01-20 17:26 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-01-14 20:39 [PATCH net-next v4 0/9] xen-netback: TX grant mapping with SKBTX_DEV_ZEROCOPY instead of copy Zoltan Kiss
2014-01-14 20:39 ` [PATCH net-next v4 1/9] xen-netback: Introduce TX grant map definitions Zoltan Kiss
2014-01-15 15:16 ` Zoltan Kiss
2014-01-16 0:00 ` Wei Liu
2014-01-20 16:53 ` Zoltan Kiss
2014-01-14 20:39 ` [PATCH net-next v4 2/9] xen-netback: Change TX path from grant copy to mapping Zoltan Kiss
2014-01-16 0:01 ` Wei Liu
2014-01-20 17:04 ` Zoltan Kiss
2014-01-14 20:39 ` [PATCH net-next v4 3/9] xen-netback: Remove old TX grant copy definitons and fix indentations Zoltan Kiss
2014-01-16 0:02 ` Wei Liu
2014-01-14 20:39 ` [PATCH net-next v4 4/9] xen-netback: Change RX path for mapped SKB fragments Zoltan Kiss
2014-01-14 20:39 ` [PATCH net-next v4 5/9] xen-netback: Add stat counters for zerocopy Zoltan Kiss
2014-01-14 20:39 ` [PATCH net-next v4 6/9] xen-netback: Handle guests with too many frags Zoltan Kiss
2014-01-16 0:03 ` Wei Liu
2014-01-20 17:26 ` Zoltan Kiss [this message]
2014-01-14 20:39 ` [PATCH net-next v4 7/9] xen-netback: Add stat counters for frag_list skbs Zoltan Kiss
2014-01-14 20:39 ` [PATCH net-next v4 8/9] xen-netback: Timeout packets in RX path Zoltan Kiss
2014-01-16 0:03 ` Wei Liu
2014-01-17 19:27 ` Zoltan Kiss
2014-01-20 16:53 ` Wei Liu
2014-01-20 17:47 ` Zoltan Kiss
2014-01-14 20:39 ` [PATCH net-next v4 9/9] xen-netback: Aggregate TX unmap operations Zoltan Kiss
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