On Fri, 3 May 2024 14:52:44 +0100, Simon Horman <horms@xxxxxxxxxx> wrote:
> On Wed, May 01, 2024 at 01:31:34AM +0800, Heng Qi wrote:
>
> ...
>
> > diff --git a/include/linux/dim.h b/include/linux/dim.h
>
> ...
>
> > @@ -198,6 +234,32 @@ enum dim_step_result {
> > DIM_ON_EDGE,
> > };
> >
> > +/**
> > + * net_dim_init_irq_moder - collect information to initialize irq moderation
> > + * @dev: target network device
> > + * @profile_flags: Rx or Tx profile modification capability
> > + * @coal_flags: irq moderation params flags
> > + * @rx_mode: CQ period mode for Rx
> > + * @tx_mode: CQ period mode for Tx
> > + * @rx_dim_work: Rx worker called after dim decision
> > + * void (*rx_dim_work)(struct work_struct *work);
> > + *
> > + * @tx_dim_work: Tx worker called after dim decision
> > + * void (*tx_dim_work)(struct work_struct *work);
> > + *
>
> Hi Heng Qi,
Hi Simon,
>
> The above seems to result in make htmldocs issuing the following warnings:
>
> .../net_dim:175: ./include/linux/dim.h:244: WARNING: Inline emphasis start-string without end-string.
> .../net_dim:175: ./include/linux/dim.h:244: WARNING: Inline emphasis start-string without end-string.
> .../net_dim:175: ./include/linux/dim.h:247: WARNING: Inline emphasis start-string without end-string.
> .../net_dim:175: ./include/linux/dim.h:247: WARNING: Inline emphasis start-string without end-string.
>
> I suggest the following alternative:
>
> * @rx_dim_work: Rx worker called after dim decision
> * @tx_dim_work: Tx worker called after dim decision
Will update this.
>
> Exercised using Sphinx 7.2.6
>
> ...
>
> > diff --git a/net/ethtool/coalesce.c b/net/ethtool/coalesce.c
>
> ...
>
> > @@ -134,6 +212,12 @@ static int coalesce_fill_reply(struct sk_buff *skb,
> > const struct coalesce_reply_data *data = COALESCE_REPDATA(reply_base);
> > const struct kernel_ethtool_coalesce *kcoal = &data->kernel_coalesce;
> > const struct ethtool_coalesce *coal = &data->coalesce;
> > +#if IS_ENABLED(CONFIG_DIMLIB)
> > + struct net_device *dev = req_base->dev;
> > + struct dim_irq_moder *moder = dev->irq_moder;
> > + u8 coal_flags;
> > + int ret;
> > +#endif
> > u32 supported = data->supported_params;
>
> It's a minor nit, but here goes: please consider using reverse xmas tree
> order - longest line to shortest - for local variable declarations in
> Networking code.
>
> In this case, I appreciate that it's not strictly possible without
> introducing more than one IS_ENABLED condition, which seems worse.
> So, as that condition breaks the visual flow, what I suggest in this
> case is having a second block of local variable declarations, like this:
>
> const struct coalesce_reply_data *data = COALESCE_REPDATA(reply_base);
> const struct kernel_ethtool_coalesce *kcoal = &data->kernel_coalesce;
> const struct ethtool_coalesce *coal = &data->coalesce;
> u32 supported = data->supported_params;
>
> #if IS_ENABLED(CONFIG_DIMLIB)
> struct dim_irq_moder *moder = dev->irq_moder;
> struct net_device *dev = req_base->dev;
Note: The line above depends on the line below. :)
However, even so, I will try to make a change to keep "xmas tree order".
> u8 coal_flags;
> int ret;
> #endif
>
> Or better still, if it can be done cleanly, moving all the IS_ENABLED()
> code in this function into a separate function, with an no-op
> implementation in the case that CONFIG_DIMLIB is not enabled. In general
> I'd recommend that approach over sprinkling IS_ENABLED or #ifdef inside
> functions. Because in my experience it tends to lead to more readable code.
>
As discussed in the previous replies, IS_ENABLED(CONFIG_DIMLIB) will be removed
in the next version, so we'll do not have this problem, but your suggestion is
good.
Thanks.
> In any case, the following tool is helpful for isolating
> reverse xmas tree issues.
>
> https://github.com/ecree-solarflare/xmastree
>
>
> > if (coalesce_put_u32(skb, ETHTOOL_A_COALESCE_RX_USECS,
> > @@ -192,11 +276,49 @@ static int coalesce_fill_reply(struct sk_buff *skb,
> > kcoal->tx_aggr_time_usecs, supported))
> > return -EMSGSIZE;
> >
> > +#if IS_ENABLED(CONFIG_DIMLIB)
> > + if (!moder)
> > + return 0;
> > +
> > + coal_flags = moder->coal_flags;
> > + rcu_read_lock();
> > + if (moder->profile_flags & DIM_PROFILE_RX) {
> > + ret = coalesce_put_profile(skb, ETHTOOL_A_COALESCE_RX_PROFILE,
> > + rcu_dereference(moder->rx_profile),
> > + coal_flags);
> > + if (ret) {
> > + rcu_read_unlock();
> > + return ret;
> > + }
> > + }
> > +
> > + if (moder->profile_flags & DIM_PROFILE_TX) {
> > + ret = coalesce_put_profile(skb, ETHTOOL_A_COALESCE_TX_PROFILE,
> > + rcu_dereference(moder->tx_profile),
> > + coal_flags);
> > + if (ret) {
> > + rcu_read_unlock();
> > + return ret;
> > + }
> > + }
> > + rcu_read_unlock();
> > +#endif
> > return 0;
> > }
>
> ...
