On Tue, May 9, 2023 at 7:56 PM Yafang Shao <laoar.shao@xxxxxxxxx> wrote:
>
> On Wed, May 10, 2023 at 1:43 AM Song Liu <song@xxxxxxxxxx> wrote:
> >
> > On Tue, May 9, 2023 at 8:15 AM Yafang Shao <laoar.shao@xxxxxxxxx> wrote:
> > >
> > > After commit e21aa341785c ("bpf: Fix fexit trampoline."), the selector
> > > is only used to indicate how many times the bpf trampoline image are
> > > updated and been displayed in the trampoline ksym name. After the
> > > trampoline is freed, the count will start from 0 again.
> > > So the count is a useless value to the user, we'd better
> > > show a more meaningful value like how many progs are linked to this
> > > trampoline. After that change, the selector can be removed eventally.
> > > If the user want to check whether the bpf trampoline image has been updated
> > > or not, the user can also compare the address. Each time the trampoline
> > > image is updated, the address will change consequently.
> >
> > I wonder whether this will cause confusion to some users. Maybe the saving
> > doesn't worth the churn.
>
> The trampoline ksym name as such:
> ffffffffc06c3000 t bpf_trampoline_6442453466_1 [bpf]
>
> I don't know what the user may use the selector for. It seems that the
> selector is meaningless. While the cnt of linked progs can really help
> users, with which the user can easily figure out how many progs are
> linked to a kernel function.
Hmm, agreed that the chance to break user space is low. Maybe we can just
remove it? IOW, only keep bpf_trampoline_6442453466
Thanks,
Song
