On 12/04/22 at 04:30pm, Dennis Zhou wrote:
> Hi Baoquan and Wupeng,
>
> On Sun, Dec 04, 2022 at 08:11:23PM +0800, Baoquan He wrote:
> > On 12/04/22 at 11:14am, Wupeng Ma wrote:
> > > From: Ma Wupeng <mawupeng1@xxxxxxxxxx>
> > >
> > > Assignment to err if is_atomic is true will never be used since warn
> > > message can only be shown if is_atomic is false after label fail. So drop
> > > it.
> > >
> > > Signed-off-by: Ma Wupeng <mawupeng1@xxxxxxxxxx>
> > > ---
> > > mm/percpu.c | 4 +---
> > > 1 file changed, 1 insertion(+), 3 deletions(-)
> > >
> > > diff --git a/mm/percpu.c b/mm/percpu.c
> > > index acd78da0493b..df86d79325b2 100644
> > > --- a/mm/percpu.c
> > > +++ b/mm/percpu.c
> > > @@ -1817,10 +1817,8 @@ static void __percpu *pcpu_alloc(size_t size, size_t align, bool reserved,
> > >
> > > spin_unlock_irqrestore(&pcpu_lock, flags);
> > >
> > > - if (is_atomic) {
> > > - err = "atomic alloc failed, no space left";
> > > + if (is_atomic)
> > > goto fail;
> > > - }
> >
> > This is good catch. But I think Dennis may not like this way because he
> > added the message intentionally in commit 11df02bf9bc1 ("percpu: resolve
> > err may not be initialized in pcpu_alloc").
> >
>
> You're right Baoquan haha. I agree with Christoph as well we should
> surface atomic.
>
> Though I don't think below is quite right either. We should likely have
> a separate warn_limit for atomic and I need to think about dump_stack()
> if there are any requirements there.
Yeah, sounds reasonable. I didn't think it over.
>
>
> > Can we change the conditional checking in fail part as below?
> >
> > diff --git a/mm/percpu.c b/mm/percpu.c
> > index 27697b2429c2..0ac55500fad9 100644
> > --- a/mm/percpu.c
> > +++ b/mm/percpu.c
> > @@ -1897,7 +1897,7 @@ static void __percpu *pcpu_alloc(size_t size, size_t align, bool reserved,
> > fail:
> > trace_percpu_alloc_percpu_fail(reserved, is_atomic, size, align);
> >
> > - if (!is_atomic && do_warn && warn_limit) {
> > + if (do_warn && warn_limit) {
> > pr_warn("allocation failed, size=%zu align=%zu atomic=%d, %s\n",
> > size, align, is_atomic, err);
> > dump_stack();
> >
>
