Re: [net-next PATCH v4 3/7] net: sock: Change tx_queue_mapping in sock_common to unsigned short
On 6/26/2018 3:58 AM, Willem de Bruijn wrote: > On Mon, Jun 25, 2018 at 7:06 PM Amritha Nambiar > wrote: >> >> Change 'skc_tx_queue_mapping' field in sock_common structure from >> 'int' to 'unsigned short' type with 0 indicating unset and >> a positive queue value being set. This way it is consistent with >> the queue_mapping field in the sk_buff. This will also accommodate >> adding a new 'unsigned short' field in sock_common in the next >> patch for rx_queue_mapping. >> >> Signed-off-by: Amritha Nambiar >> --- > >> static inline void sk_tx_queue_set(struct sock *sk, int tx_queue) >> { >> - sk->sk_tx_queue_mapping = tx_queue; >> + /* sk_tx_queue_mapping accept only upto a 16-bit value */ >> + WARN_ON((unsigned short)tx_queue > USHRT_MAX); >> + sk->sk_tx_queue_mapping = tx_queue + 1; >> } > > WARN_ON_ONCE to avoid flooding the kernel buffer. > Will fix.
Re: [net-next PATCH v4 3/7] net: sock: Change tx_queue_mapping in sock_common to unsigned short
On 6/25/2018 8:25 PM, Alexander Duyck wrote: > On Mon, Jun 25, 2018 at 6:34 PM, Tom Herbert wrote: >> >> >> On Mon, Jun 25, 2018 at 11:04 AM, Amritha Nambiar >> wrote: >>> >>> Change 'skc_tx_queue_mapping' field in sock_common structure from >>> 'int' to 'unsigned short' type with 0 indicating unset and >>> a positive queue value being set. This way it is consistent with >>> the queue_mapping field in the sk_buff. This will also accommodate >>> adding a new 'unsigned short' field in sock_common in the next >>> patch for rx_queue_mapping. >>> >>> Signed-off-by: Amritha Nambiar >>> --- >>> include/net/sock.h | 10 ++ >>> 1 file changed, 6 insertions(+), 4 deletions(-) >>> >>> diff --git a/include/net/sock.h b/include/net/sock.h >>> index b3b7541..009fd30 100644 >>> --- a/include/net/sock.h >>> +++ b/include/net/sock.h >>> @@ -214,7 +214,7 @@ struct sock_common { >>> struct hlist_node skc_node; >>> struct hlist_nulls_node skc_nulls_node; >>> }; >>> - int skc_tx_queue_mapping; >>> + unsigned short skc_tx_queue_mapping; >>> union { >>> int skc_incoming_cpu; >>> u32 skc_rcv_wnd; >>> @@ -1681,17 +1681,19 @@ static inline int sk_receive_skb(struct sock *sk, >>> struct sk_buff *skb, >>> >>> static inline void sk_tx_queue_set(struct sock *sk, int tx_queue) >>> { >>> - sk->sk_tx_queue_mapping = tx_queue; >>> + /* sk_tx_queue_mapping accept only upto a 16-bit value */ >>> + WARN_ON((unsigned short)tx_queue > USHRT_MAX); >> >> >> Shouldn't this be USHRT_MAX - 1 ? > > Actually just a ">=" would probably do as well. Ugh! Will definitely fix this. > >> >>> + sk->sk_tx_queue_mapping = tx_queue + 1; >>> } >>> >>> static inline void sk_tx_queue_clear(struct sock *sk) >>> { >>> - sk->sk_tx_queue_mapping = -1; >>> >>> + sk->sk_tx_queue_mapping = 0; >> >> >> I think it's slightly better to define a new constant like NO_QUEUE_MAPPING >> to be USHRT_MAX. That avoids needing to do the arithmetic every time the >> value is accessed. The idea was to have avoid having to make any changes to the callers of these functions and make this similar to queue_mapping in skbuff with 0 indicating unset and +ve value for set. sk_tx_queue_get returns -1 on invalid and the callers were validating -ve values. With sk_tx_queue_mapping initialized to USHRT_MAX, and having an additional check in sk_tx_queue_get to return -1 if sk_tx_queue_mapping has USHRT_MAX, I think I can keep changes minimal and avoid the arithmetic if that's a more acceptable solution. >>> >>> } >>> >>> static inline int sk_tx_queue_get(const struct sock *sk) >>> { >>> - return sk ? sk->sk_tx_queue_mapping : -1; >>> + return sk ? sk->sk_tx_queue_mapping - 1 : -1; >> >> >> Doesn't the comparison in __netdev_pick_tx need to be simultaneously changed >> for this? > > This doesn't change the result. It was still -1 if the queue mapping > is not set. It was just initialized to 0 instead of to -1 so we have > to perform the operation to get there. > > Also in regards to the comment above about needing an extra operation > I am not sure it makes much difference. > > In the case of us starting with 0 as a reserved value I think the > instruction count should be about the same. We move the unsigned short > into an unsigned in, then decrement, and if the value is non-negative > we can assume it is valid. Although maybe I should double check the > code to make certain it is doing what I thought it was supposed to be > doing. > >> >>> >>> >>> >>> } >>> >>> static inline void sk_set_socket(struct sock *sk, struct socket *sock) >>> >>
Re: [net-next PATCH v4 3/7] net: sock: Change tx_queue_mapping in sock_common to unsigned short
On Mon, Jun 25, 2018 at 7:06 PM Amritha Nambiar wrote: > > Change 'skc_tx_queue_mapping' field in sock_common structure from > 'int' to 'unsigned short' type with 0 indicating unset and > a positive queue value being set. This way it is consistent with > the queue_mapping field in the sk_buff. This will also accommodate > adding a new 'unsigned short' field in sock_common in the next > patch for rx_queue_mapping. > > Signed-off-by: Amritha Nambiar > --- > static inline void sk_tx_queue_set(struct sock *sk, int tx_queue) > { > - sk->sk_tx_queue_mapping = tx_queue; > + /* sk_tx_queue_mapping accept only upto a 16-bit value */ > + WARN_ON((unsigned short)tx_queue > USHRT_MAX); > + sk->sk_tx_queue_mapping = tx_queue + 1; > } WARN_ON_ONCE to avoid flooding the kernel buffer.
Re: [net-next PATCH v4 3/7] net: sock: Change tx_queue_mapping in sock_common to unsigned short
On Mon, Jun 25, 2018 at 6:34 PM, Tom Herbert wrote: > > > On Mon, Jun 25, 2018 at 11:04 AM, Amritha Nambiar > wrote: >> >> Change 'skc_tx_queue_mapping' field in sock_common structure from >> 'int' to 'unsigned short' type with 0 indicating unset and >> a positive queue value being set. This way it is consistent with >> the queue_mapping field in the sk_buff. This will also accommodate >> adding a new 'unsigned short' field in sock_common in the next >> patch for rx_queue_mapping. >> >> Signed-off-by: Amritha Nambiar >> --- >> include/net/sock.h | 10 ++ >> 1 file changed, 6 insertions(+), 4 deletions(-) >> >> diff --git a/include/net/sock.h b/include/net/sock.h >> index b3b7541..009fd30 100644 >> --- a/include/net/sock.h >> +++ b/include/net/sock.h >> @@ -214,7 +214,7 @@ struct sock_common { >> struct hlist_node skc_node; >> struct hlist_nulls_node skc_nulls_node; >> }; >> - int skc_tx_queue_mapping; >> + unsigned short skc_tx_queue_mapping; >> union { >> int skc_incoming_cpu; >> u32 skc_rcv_wnd; >> @@ -1681,17 +1681,19 @@ static inline int sk_receive_skb(struct sock *sk, >> struct sk_buff *skb, >> >> static inline void sk_tx_queue_set(struct sock *sk, int tx_queue) >> { >> - sk->sk_tx_queue_mapping = tx_queue; >> + /* sk_tx_queue_mapping accept only upto a 16-bit value */ >> + WARN_ON((unsigned short)tx_queue > USHRT_MAX); > > > Shouldn't this be USHRT_MAX - 1 ? Actually just a ">=" would probably do as well. > >> + sk->sk_tx_queue_mapping = tx_queue + 1; >> } >> >> static inline void sk_tx_queue_clear(struct sock *sk) >> { >> - sk->sk_tx_queue_mapping = -1; >> >> + sk->sk_tx_queue_mapping = 0; > > > I think it's slightly better to define a new constant like NO_QUEUE_MAPPING > to be USHRT_MAX. That avoids needing to do the arithmetic every time the > value is accessed. >> >> } >> >> static inline int sk_tx_queue_get(const struct sock *sk) >> { >> - return sk ? sk->sk_tx_queue_mapping : -1; >> + return sk ? sk->sk_tx_queue_mapping - 1 : -1; > > > Doesn't the comparison in __netdev_pick_tx need to be simultaneously changed > for this? This doesn't change the result. It was still -1 if the queue mapping is not set. It was just initialized to 0 instead of to -1 so we have to perform the operation to get there. Also in regards to the comment above about needing an extra operation I am not sure it makes much difference. In the case of us starting with 0 as a reserved value I think the instruction count should be about the same. We move the unsigned short into an unsigned in, then decrement, and if the value is non-negative we can assume it is valid. Although maybe I should double check the code to make certain it is doing what I thought it was supposed to be doing. > >> >> >> >> } >> >> static inline void sk_set_socket(struct sock *sk, struct socket *sock) >> >
[net-next PATCH v4 3/7] net: sock: Change tx_queue_mapping in sock_common to unsigned short
Change 'skc_tx_queue_mapping' field in sock_common structure from 'int' to 'unsigned short' type with 0 indicating unset and a positive queue value being set. This way it is consistent with the queue_mapping field in the sk_buff. This will also accommodate adding a new 'unsigned short' field in sock_common in the next patch for rx_queue_mapping. Signed-off-by: Amritha Nambiar --- include/net/sock.h | 10 ++ 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/include/net/sock.h b/include/net/sock.h index b3b7541..009fd30 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -214,7 +214,7 @@ struct sock_common { struct hlist_node skc_node; struct hlist_nulls_node skc_nulls_node; }; - int skc_tx_queue_mapping; + unsigned short skc_tx_queue_mapping; union { int skc_incoming_cpu; u32 skc_rcv_wnd; @@ -1681,17 +1681,19 @@ static inline int sk_receive_skb(struct sock *sk, struct sk_buff *skb, static inline void sk_tx_queue_set(struct sock *sk, int tx_queue) { - sk->sk_tx_queue_mapping = tx_queue; + /* sk_tx_queue_mapping accept only upto a 16-bit value */ + WARN_ON((unsigned short)tx_queue > USHRT_MAX); + sk->sk_tx_queue_mapping = tx_queue + 1; } static inline void sk_tx_queue_clear(struct sock *sk) { - sk->sk_tx_queue_mapping = -1; + sk->sk_tx_queue_mapping = 0; } static inline int sk_tx_queue_get(const struct sock *sk) { - return sk ? sk->sk_tx_queue_mapping : -1; + return sk ? sk->sk_tx_queue_mapping - 1 : -1; } static inline void sk_set_socket(struct sock *sk, struct socket *sock)