Re: [PATCH net-next 2/2] tcp: adjust rcv zerocopy hints based on frag sizes

2018-10-01 Thread David Miller
From: Soheil Hassas Yeganeh 
Date: Wed, 26 Sep 2018 16:57:04 -0400

> From: Soheil Hassas Yeganeh 
> 
> When SKBs are coalesced, we can have SKBs with different
> frag sizes. Some with PAGE_SIZE and some not with PAGE_SIZE.
> Since recv_skip_hint is always set to the full SKB size,
> it can overestimate the amount that should be read using
> normal read for coalesced packets.
> 
> Change the recv_skip_hint so that it only includes the first
> frags that are not of PAGE_SIZE.
> 
> Signed-off-by: Soheil Hassas Yeganeh 
> Signed-off-by: Eric Dumazet 

Applied.


[PATCH net-next 2/2] tcp: adjust rcv zerocopy hints based on frag sizes

2018-09-26 Thread Soheil Hassas Yeganeh
From: Soheil Hassas Yeganeh 

When SKBs are coalesced, we can have SKBs with different
frag sizes. Some with PAGE_SIZE and some not with PAGE_SIZE.
Since recv_skip_hint is always set to the full SKB size,
it can overestimate the amount that should be read using
normal read for coalesced packets.

Change the recv_skip_hint so that it only includes the first
frags that are not of PAGE_SIZE.

Signed-off-by: Soheil Hassas Yeganeh 
Signed-off-by: Eric Dumazet 
---
 net/ipv4/tcp.c | 11 ++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 3e17501fc1a1..cdbd423bdeb4 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -1805,8 +1805,17 @@ static int tcp_zerocopy_receive(struct sock *sk,
frags++;
}
}
-   if (frags->size != PAGE_SIZE || frags->page_offset)
+   if (frags->size != PAGE_SIZE || frags->page_offset) {
+   int remaining = zc->recv_skip_hint;
+
+   while (remaining && (frags->size != PAGE_SIZE ||
+frags->page_offset)) {
+   remaining -= frags->size;
+   frags++;
+   }
+   zc->recv_skip_hint -= remaining;
break;
+   }
ret = vm_insert_page(vma, address + length,
 skb_frag_page(frags));
if (ret)
-- 
2.19.0.605.g01d371f741-goog