Re: [RFC PATCH v1 1/5] locking/atomic: Implement atomic_fetch_and_or

From: Hev <r@hev.cc>
To: Boqun Feng <boqun.feng@gmail.com>
Cc: Rui Wang <wangrui@loongson.cn>,
	Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@redhat.com>, Will Deacon <will@kernel.org>,
	Arnd Bergmann <arnd@arndb.de>, Waiman Long <longman@redhat.com>,
	Guo Ren <guoren@kernel.org>,
	linux-arch@vger.kernel.org, Xuefeng Li <lixuefeng@loongson.cn>,
	Huacai Chen <chenhuacai@gmail.com>,
	Jiaxun Yang <jiaxun.yang@flygoat.com>,
	Huacai Chen <chenhuacai@loongson.cn>
Subject: Re: [RFC PATCH v1 1/5] locking/atomic: Implement atomic_fetch_and_or
Date: Wed, 28 Jul 2021 22:12:41 +0800	[thread overview]
Message-ID: <CAHirt9irQ8bio3HE-xTtQcDa5wJB1yXhZ4BJsgU7vW-FEYhLcA@mail.gmail.com> (raw)
In-Reply-To: <YQFKNcyHHWph8SjO@boqun-archlinux>

Hi, Boqun,

On Wed, Jul 28, 2021 at 8:15 PM Boqun Feng <boqun.feng@gmail.com> wrote:
>
> Hi,
>
> Thanks for the patchset. Seems that your git send-email command doesn't
> add the "In-Reply-to" tag for patch #2 to #5, so they are not threaded
> to patch #1. Not a big deal, but archives or email clients use that
> information to organize emails. You may want to check the command. Also,
> note that you can always use "--dry-run" option to preview the headers
> of your patchset ("--dry-run" won't do the actual send).
Thanks for your advice.

>
> On Wed, Jul 28, 2021 at 07:48:22PM +0800, Rui Wang wrote:
> > From: wangrui <wangrui@loongson.cn>
> >
> > This patch introduce a new atomic primitive 'and_or', It may be have three
> > types of implemeations:
> >
> >  * The generic implementation is based on arch_cmpxchg.
> >  * The hardware supports atomic 'and_or' of single instruction.
> >  * The hardware supports LL/SC style atomic operations:
> >
> >    1:  ll  v1, mem
> >        and t1, v1, arg1
> >        or  t1, t1, arg2
> >        sc  t1, mem
> >        beq t1, 0, 1b
> >
> > Now that all the architectures have implemented it.
> >
> > Signed-by-off: Rui Wang <wangrui@loongson.cn>
> > Signed-by-off: hev <r@hev.cc>
>
> First, this should be "Signed-off-by" ;-) Second, is the second
> "Signed-off-by" a mistake?
Beginner's luck :-)

>
> I will look into this for a review, in the meanwhile, but please add
> some tests in lib/atomic64_test.c, not only it will do the test at
> runtime, also it will generate asm code which helps people to review.
>
> Regards,
> Boqun
>

Regards,
Rui