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Message-ID: <d94ba990b99c01853cdb190895185ef3b7834fb1.camel@redhat.com>
Subject: Re: [PATCH V3 net 1/2] net: hns: fix wrong head when modify the tx
 feature when sending packets
From:   Paolo Abeni <pabeni@redhat.com>
To:     Jijie Shao <shaojijie@huawei.com>, yisen.zhuang@huawei.com,
        salil.mehta@huawei.com, davem@davemloft.net, edumazet@google.com,
        kuba@kernel.org, wojciech.drewek@intel.com
Cc:     shenjian15@huawei.com, wangjie125@huawei.com,
        liuyonglong@huawei.com, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org
Date:   Wed, 06 Dec 2023 15:27:58 +0100
In-Reply-To: <f7588e40-0fea-4350-89fe-c432eacb68f7@huawei.com>
References: <20231204143232.3221542-1-shaojijie@huawei.com>
         <20231204143232.3221542-2-shaojijie@huawei.com>
         <ffd7a4cbefa8c4f435db5bab0f5f7f2d4e2dad73.camel@redhat.com>
         <f7588e40-0fea-4350-89fe-c432eacb68f7@huawei.com>
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On Wed, 2023-12-06 at 20:31 +0800, Jijie Shao wrote:
> on 2023/12/6 19:18, Paolo Abeni wrote:
> > +		priv->ops.fill_desc =3D fill_desc_v2;
> > +		priv->ops.maybe_stop_tx =3D hns_nic_maybe_stop_tx_v2;
> > Side note: since both 'fill_desc' and 'maybe_stop_tx' have constant
> > values, for net-next you should really consider replacing the function
> > pointers with direct-calls.
> >=20
> > You currently have at least 2 indirect calls per wire packet, which
> > hurt performances a lot in case security issues mitigations are in
> > place.
> >=20
> > Cheers,
> >=20
> > Paolo
>=20
> Thank you for your advice. Currently, because the hardware behavior is=
=20
> different, the two versions of ops are retained to unify the subsequent=
=20
> process. We will try to unify the two version ops, and if that does not=
=20
> work, we will consider maintaining the status quo. Thanks again! Jijie

Note that even if you will have to resort to call different functions
for different H/W revisions, from performance PoV you will be far
better off doing a test at runtime to call the corresponding helper.

Or you can use the indirect call wrappers - have a look into:

include/linux/indirect_call_wrapper.h

Cheers,

Paolo