From: Xiao Guangrong <guangrong.xiao@gmail.com>
To: Paolo Bonzini <pbonzini@redhat.com>, "Emilio G. Cota" <cota@braap.org>
Cc: mst@redhat.com, mtosatti@redhat.com, kvm@vger.kernel.org,
quintela@redhat.com, Xiao Guangrong <xiaoguangrong@tencent.com>,
qemu-devel@nongnu.org, peterx@redhat.com, dgilbert@redhat.com,
wei.w.wang@intel.com, jiang.biao2@zte.com.cn
Subject: Re: [Qemu-devel] [PATCH 1/4] ptr_ring: port ptr_ring from linux kernel to QEMU
Date: Thu, 18 Oct 2018 14:52:17 +0800 [thread overview]
Message-ID: <a37a8ddb-e6f3-083c-1251-cba835a214f8@gmail.com> (raw)
In-Reply-To: <40c0df2a-5a3e-5296-0894-efadf47f3d56@redhat.com>
On 10/17/2018 04:14 PM, Paolo Bonzini wrote:
> On 16/10/2018 18:40, Emilio G. Cota wrote:
>>> +#define SMP_CACHE_BYTES 64
>>> +#define ____cacheline_aligned_in_smp \
>>> + __attribute__((__aligned__(SMP_CACHE_BYTES)))
>> You could use QEMU_ALIGNED() here.
Yes, you are right.
>>
>>> +
>>> +#define WRITE_ONCE(ptr, val) \
>>> + (*((volatile typeof(ptr) *)(&(ptr))) = (val))
>>> +#define READ_ONCE(ptr) (*((volatile typeof(ptr) *)(&(ptr))))
>> Why not atomic_read/set, like in the rest of the QEMU code base?
>
> Or even atomic_rcu_read/atomic_rcu_set, which includes the necessary
> barriers.
>
Okay, will fix it, thank you and Emilio for pointing the
issue out.
> Also, please do not use __ identifiers in QEMU code.
> ____cacheline_aligned_in_smp can become just QEMU_ALIGNED(SMP_CACHE_BYTES).
>
Sure, will keep that in my mind. :)
next prev parent reply other threads:[~2018-10-18 6:52 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-16 11:10 [Qemu-devel] [PATCH 0/4] migration: improve multithreads guangrong.xiao
2018-10-16 11:10 ` [Qemu-devel] [PATCH 1/4] ptr_ring: port ptr_ring from linux kernel to QEMU guangrong.xiao
2018-10-16 16:40 ` Emilio G. Cota
2018-10-17 8:14 ` Paolo Bonzini
2018-10-18 6:52 ` Xiao Guangrong [this message]
2018-10-16 11:10 ` [Qemu-devel] [PATCH 2/4] migration: introduce lockless multithreads model guangrong.xiao
2018-10-17 10:10 ` Paolo Bonzini
2018-10-18 9:30 ` Xiao Guangrong
2018-10-18 10:39 ` Paolo Bonzini
2018-10-26 23:33 ` Emilio G. Cota
2018-10-28 7:50 ` Paolo Bonzini
2018-10-29 2:52 ` Xiao Guangrong
2018-10-16 11:10 ` [Qemu-devel] [PATCH 3/4] migration: use lockless Multithread model for compression guangrong.xiao
2018-10-16 11:10 ` [Qemu-devel] [PATCH 4/4] migration: use lockless Multithread model for decompression guangrong.xiao
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