Re: [PATCH bpf-next v2 27/35] bpf: eliminate rlimit-based memory accounting infra for bpf maps
From: Song Liu
Date: Tue Jul 28 2020 - 02:07:04 EST
On Mon, Jul 27, 2020 at 10:58 PM Andrii Nakryiko
> On Mon, Jul 27, 2020 at 10:47 PM Song Liu <song@xxxxxxxxxx> wrote:
> > On Mon, Jul 27, 2020 at 12:26 PM Roman Gushchin <guro@xxxxxx> wrote:
> > >
> > > Remove rlimit-based accounting infrastructure code, which is not used
> > > anymore.
> > >
> > > Signed-off-by: Roman Gushchin <guro@xxxxxx>
> > [...]
> > >
> > > static void bpf_map_put_uref(struct bpf_map *map)
> > > @@ -541,7 +484,7 @@ static void bpf_map_show_fdinfo(struct seq_file *m, struct file *filp)
> > > "value_size:\t%u\n"
> > > "max_entries:\t%u\n"
> > > "map_flags:\t%#x\n"
> > > - "memlock:\t%llu\n"
> > > + "memlock:\t%llu\n" /* deprecated */
> > I am not sure whether we can deprecate this one.. How difficult is it
> > to keep this statistics?
> It's factually correct now, that BPF map doesn't use any memlock memory, no?
I am not sure whether memlock really means memlock for all users... I bet there
are users who use memlock to check total memory used by the map.
> This is actually one way to detect whether RLIMIT_MEMLOCK is necessary
> or not: create a small map, check if it's fdinfo has memlock: 0 or not
If we do show memlock=0, this is a good check...