From: Aleksandr Nogikh <firstname.lastname@example.org> To: Willem de Bruijn <email@example.com>, Jakub Kicinski <firstname.lastname@example.org> Cc: Aleksandr Nogikh <email@example.com>, Dmitry Vyukov <firstname.lastname@example.org>, David Miller <email@example.com>, Johannes Berg <firstname.lastname@example.org>, Eric Dumazet <email@example.com>, Andrey Konovalov <firstname.lastname@example.org>, Marco Elver <email@example.com>, LKML <firstname.lastname@example.org>, netdev <email@example.com>, linux-wireless <firstname.lastname@example.org>, Florian Westphal <email@example.com> Subject: Re: [PATCH 1/2] net: store KCOV remote handle in sk_buff Date: Fri, 16 Oct 2020 17:20:42 +0300 [thread overview] Message-ID: <CANp29Y69mvAuwdcNk8DyjYSjDMBkQupMh0JHHLkybg+rA2zCLw@mail.gmail.com> (raw) In-Reply-To: <CA+FuTSf2kfvdYydXYJNCCfE62q9DXXOBMh_ZSO5W=L9GK478HA@mail.gmail.com> On Thu, Oct 15, 2020 at 10:04 PM Willem de Bruijn <firstname.lastname@example.org> wrote: > > On Tue, Oct 13, 2020 at 12:50 PM Jakub Kicinski <email@example.com> wrote: > > > > On Tue, 13 Oct 2020 18:59:28 +0300 Aleksandr Nogikh wrote: > > > On Mon, 12 Oct 2020 at 09:04, Dmitry Vyukov <firstname.lastname@example.org> wrote: > > > > > > > > On Sat, Oct 10, 2020 at 5:14 PM Jakub Kicinski <email@example.com> wrote: > > > > > > > > > > On Sat, 10 Oct 2020 09:54:57 +0200 Dmitry Vyukov wrote: > > > > > > On Sat, Oct 10, 2020 at 1:16 AM Jakub Kicinski <firstname.lastname@example.org> wrote: > > > [...] > > > > > > > Could you use skb_extensions for this? > > > > > > > > > > > > Why? If for space, this is already under a non-production ifdef. > > > > > > > > > > I understand, but the skb_ext infra is there for uncommon use cases > > > > > like this one. Any particular reason you don't want to use it? > > > > > The slight LoC increase? > > > > > > > > > > Is there any precedent for adding the kcov field to other performance > > > > > critical structures? > > > > > > It would be great to come to some conclusion on where exactly to store > > > kcov_handle. Technically, it is possible to use skb extensions for the > > > purpose, though it will indeed slightly increase the complexity. > > > > > > Jakub, you think that kcov_handle should be added as an skb extension, > > > right? > > > > That'd be preferable. I understand with current use cases it doesn't > > really matter, but history shows people come up with all sort of > > wonderful use cases down the line. And when they do they rarely go back > > and fix such fundamental minutiae. > > > > > Though I do not really object to moving the field, it still seems to > > > me that sk_buff itself is a better place. Right now skb extensions > > > store values that are local to specific protocols and that are only > > > meaningful in the context of these protocols (correct me if I'm > > > wrong). Although this patch only adds remote kcov coverage to the wifi > > > code, kcov_handle can be meaningful for other protocols as well - just > > > like the already existing sk_buff fields. So adding kcov_handle to skb > > > extensions will break this logical separation. > > > > It's not as much protocols as subsystems. The values are meaningful to > > a subsystem which inserts them, that doesn't mean single layer of the > > stack. If it was about storing layer's context we would just use > > skb->cb. > > > > So I think the kcov use matches pretty well. > > skb_extensions was the first thing that came to mind when I read this > patchset too. It is not specific to protocols. > > We have long stopped growing sk_buff size. Thank you all for your comments. I'll use skb extensions in v3 of the series.
next prev parent reply other threads:[~2020-10-16 14:20 UTC|newest] Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-10-07 10:17 [PATCH 0/2] net, mac80211: enable KCOV remote coverage collection for 802.11 frame handling Aleksandr Nogikh 2020-10-07 10:17 ` [PATCH 1/2] net: store KCOV remote handle in sk_buff Aleksandr Nogikh 2020-10-09 23:15 ` Jakub Kicinski 2020-10-10 7:54 ` Dmitry Vyukov 2020-10-10 15:14 ` Jakub Kicinski 2020-10-12 6:04 ` Dmitry Vyukov 2020-10-13 15:59 ` Aleksandr Nogikh 2020-10-13 16:50 ` Jakub Kicinski 2020-10-15 19:04 ` Willem de Bruijn 2020-10-16 14:20 ` Aleksandr Nogikh [this message] 2020-10-12 7:12 ` Johannes Berg 2020-10-12 10:10 ` Aleksandr Nogikh 2020-10-07 10:17 ` [PATCH 2/2] mac80211: add KCOV remote annotations to incoming frame processing Aleksandr Nogikh 2020-10-07 11:48 ` [PATCH 0/2] net, mac80211: enable KCOV remote coverage collection for 802.11 frame handling Johannes Berg 2020-10-07 14:40 ` Aleksandr Nogikh
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