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References: <20181122072028.22819-1-xiaoguangrong@tencent.com>
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	<20181124001231.GE17229@flamenco>
From: Xiao Guangrong <guangrong.xiao@gmail.com>
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Date: Mon, 26 Nov 2018 16:06:37 +0800
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Subject: Re: [Qemu-devel] [PATCH v3 2/5] util: introduce threaded workqueue
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To: "Emilio G. Cota" <cota@braap.org>
Cc: pbonzini@redhat.com, mst@redhat.com, mtosatti@redhat.com, qemu-devel@nongnu.org, kvm@vger.kernel.org, dgilbert@redhat.com, peterx@redhat.com, wei.w.wang@intel.com, jiang.biao2@zte.com.cn, eblake@redhat.com, quintela@redhat.com, Xiao Guangrong <xiaoguangrong@tencent.com>



On 11/24/18 8:12 AM, Emilio G. Cota wrote:
> On Thu, Nov 22, 2018 at 15:20:25 +0800, guangrong.xiao@gmail.com wrote:
>> +   /*
>> +     * the bit in these two bitmaps indicates the index of the ＠requests
> 
> This @ is not ASCII, is it?
> 

Good eyes. :)

Will fix it.

>> +     * respectively. If it's the same, the corresponding request is free
>> +     * and owned by the user, i.e, where the user fills a request. Otherwise,
>> +     * it is valid and owned by the thread, i.e, where the thread fetches
>> +     * the request and write the result.
>> +     */
>> +
>> +    /* after the user fills the request, the bit is flipped. */
>> +    uint64_t request_fill_bitmap QEMU_ALIGNED(SMP_CACHE_BYTES);
>> +    /* after handles the request, the thread flips the bit. */
>> +    uint64_t request_done_bitmap QEMU_ALIGNED(SMP_CACHE_BYTES);
> 
> Use DECLARE_BITMAP, otherwise you'll get type errors as David
> pointed out.

If we do it, the field becomes a pointer... that complicates the
thing.

Hmm, i am using the same trick applied by kvm module when it handles
vcpu->requests:
static inline bool kvm_test_request(int req, struct kvm_vcpu *vcpu)
{
	return test_bit(req & KVM_REQUEST_MASK, (void *)&vcpu->requests);
}

Is it good?