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Subject: Re: [PATCH] xen/balloon: use a kernel thread instead a workqueue
To:     Juergen Gross <jgross@suse.com>, xen-devel@lists.xenproject.org,
        linux-kernel@vger.kernel.org
Cc:     Stefano Stabellini <sstabellini@kernel.org>,
        Jan Beulich <jbeulich@suse.com>
References: <20210827123206.15429-1-jgross@suse.com>
 <8b13525b-0075-f4c1-8900-1be151e85e3e@oracle.com>
 <9d1edc4e-b2b5-c620-17c6-31d238c2c417@suse.com>
From:   Boris Ostrovsky <boris.ostrovsky@oracle.com>
Message-ID: <97f394d4-6538-a931-6531-063998c6c5e2@oracle.com>
Date:   Wed, 8 Sep 2021 12:05:24 -0400
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On 9/8/21 11:11 AM, Juergen Gross wrote:
> On 08.09.21 16:47, Boris Ostrovsky wrote:
>>
>>
>> Given that wait_event_interruptible_timeout() is a bunch of nested macros do we need to worry here about overly aggressive compiler optimizing out 'credit = current_credit()'?
>
> I don't think so. current_credit() is reading from balloon_stats, which
> is a global variable. So the compiler shouldn't assume the contents
> won't change.


Ah, ok --- good point. Then I guess we should be fine.


Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>


>
> But I can add a barrier() after 'credit = current_credit()' in case
> you'd feel uneasy without it.
>
>
> Juergen