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.
Thanks,
Dennis
> 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();
>
