> -----邮件原件-----
> 发件人: dev <dev-boun...@dpdk.org> 代表 Jerin Jacob
> 发送时间: Thursday, October 28, 2021 3:02 PM
> 收件人: Feifei Wang <feifei.wa...@arm.com>
> 抄送: Honnappa Nagarahalli <honnappa.nagaraha...@arm.com>; dpdk-dev
> <dev@dpdk.org>; nd <n...@arm.com>; Ananyev, Konstantin
> <konstantin.anan...@intel.com>; Stephen Hemminger
> <step...@networkplumber.org>; David Marchand
> <david.march...@redhat.com>; tho...@monjalon.net; Mattias Rönnblom
> <mattias.ronnb...@ericsson.com>; Ruifeng Wang <ruifeng.w...@arm.com>
> 主题: Re: [dpdk-dev] [PATCH v7 3/5] eal: use wait event scheme for mcslock
>
> On Thu, Oct 28, 2021 at 12:27 PM Feifei Wang <feifei.wa...@arm.com>
> wrote:
> >
> > Instead of polling for mcslock to be updated, use wait event scheme
> > for this case.
> >
> > Furthermore, use 'uintptr_t *' is for different size of pointer in
> > 32/64 bits architecture.
> >
> > And define a new pointer 'next' for the compilation error:
> > -------------------------------------------------------------------
> > 'dereferencing type-punned pointer will break strict-aliasing rules'
> > -------------------------------------------------------------------
> >
> > Signed-off-by: Feifei Wang <feifei.wa...@arm.com>
> > Reviewed-by: Ruifeng Wang <ruifeng.w...@arm.com>
> > ---
> > lib/eal/include/generic/rte_mcslock.h | 5 +++--
> > 1 file changed, 3 insertions(+), 2 deletions(-)
> >
> > diff --git a/lib/eal/include/generic/rte_mcslock.h
> > b/lib/eal/include/generic/rte_mcslock.h
> > index 34f33c64a5..d5b9b293cd 100644
> > --- a/lib/eal/include/generic/rte_mcslock.h
> > +++ b/lib/eal/include/generic/rte_mcslock.h
> > @@ -116,8 +116,9 @@ rte_mcslock_unlock(rte_mcslock_t **msl,
> rte_mcslock_t *me)
> > /* More nodes added to the queue by other CPUs.
> > * Wait until the next pointer is set.
> > */
> > - while (__atomic_load_n(&me->next, __ATOMIC_RELAXED) ==
> NULL)
> > - rte_pause();
> > + uintptr_t *next = NULL;
>
> It is going to update in the next line. Why explicit NULL assignment?
You are right, it is unnecessary to initialize it as NULL. I will update this.
>
> > + next = (uintptr_t *)&me->next;
> > + rte_wait_event(next, UINTPTR_MAX, ==, 0,
> > + __ATOMIC_RELAXED);
> > }
> >
> > /* Pass lock to next waiter. */
> > --
> > 2.25.1
> >
