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From: Emanuele Giuseppe Esposito <eesposit@redhat.com>
To: Stefan Hajnoczi <stefanha@redhat.com>
Cc: Kevin Wolf <kwolf@redhat.com>,
	Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>,
	qemu-block@nongnu.org, qemu-devel@nongnu.org,
	Wen Congyang <wencongyang2@huawei.com>,
	Xie Changlong <xiechanglong.d@gmail.com>,
	Markus Armbruster <armbru@redhat.com>,
	Max Reitz <mreitz@redhat.com>,
	Paolo Bonzini <pbonzini@redhat.com>, John Snow <jsnow@redhat.com>
Subject: Re: [RFC PATCH 4/6] job.h: categorize job fields
Date: Mon, 12 Jul 2021 10:43:36 +0200	[thread overview]
Message-ID: <2faaf85c-3979-2f5a-723d-98cf214baf4a@redhat.com> (raw)
In-Reply-To: <YObbS4aY/9bFBaFX@stefanha-x1.localdomain>



On 08/07/2021 13:02, Stefan Hajnoczi wrote:
> On Wed, Jul 07, 2021 at 06:58:11PM +0200, Emanuele Giuseppe Esposito wrote:
>> -    /** AioContext to run the job coroutine in */
>> +    /**
>> +     * AioContext to run the job coroutine in.
>> +     * Atomic.
>> +     */
>>       AioContext *aio_context;
> 
> This isn't accessed using atomic operations, so I'm not sure why it's
> documented as atomic?
> 
Maybe this is unnecessary, but from what I understand right now when we 
want to change the AioContext of a child node, we need to acquire its 
AioContext lock, and then we try to set it. Without AioContext locks, my 
understanding is that this has to be protected somehow. Therefore I 
thought of setting this pointer atomically (actual code that does this 
is in patch 5).

Again same reasoning style applies here: this patch just adds a bounce 
of comments, but merging it with next one would just make it more 
unreadable.

Emanuele



  reply	other threads:[~2021-07-12  8:45 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-07 16:58 [RFC PATCH 0/6] job: replace AioContext lock with job_mutex Emanuele Giuseppe Esposito
2021-07-07 16:58 ` [RFC PATCH 1/6] job: use getter/setters instead of accessing the Job fields directly Emanuele Giuseppe Esposito
2021-07-07 16:58 ` [RFC PATCH 2/6] job: _locked functions and public job_lock/unlock for next patch Emanuele Giuseppe Esposito
2021-07-08 10:50   ` Stefan Hajnoczi
2021-07-12  8:43     ` Emanuele Giuseppe Esposito
2021-07-13 13:32       ` Stefan Hajnoczi
2021-07-07 16:58 ` [RFC PATCH 3/6] job: minor changes to simplify locking Emanuele Giuseppe Esposito
2021-07-08 10:55   ` Stefan Hajnoczi
2021-07-12  8:43     ` Emanuele Giuseppe Esposito
2021-07-13 17:56   ` Eric Blake
2021-07-07 16:58 ` [RFC PATCH 4/6] job.h: categorize job fields Emanuele Giuseppe Esposito
2021-07-08 11:02   ` Stefan Hajnoczi
2021-07-12  8:43     ` Emanuele Giuseppe Esposito [this message]
2021-07-07 16:58 ` [RFC PATCH 5/6] job: use global job_mutex to protect struct Job Emanuele Giuseppe Esposito
2021-07-08 12:56   ` Stefan Hajnoczi
2021-07-12  8:43     ` Emanuele Giuseppe Esposito
2021-07-07 16:58 ` [RFC PATCH 6/6] jobs: remove unnecessary AioContext aquire/release pairs Emanuele Giuseppe Esposito
2021-07-08 10:36 ` [RFC PATCH 0/6] job: replace AioContext lock with job_mutex Stefan Hajnoczi
2021-07-08 11:32   ` Paolo Bonzini
2021-07-08 12:14     ` Kevin Wolf
2021-07-08 13:04     ` Stefan Hajnoczi
2021-07-12  8:41       ` Emanuele Giuseppe Esposito
2021-07-13 13:10         ` Stefan Hajnoczi
2021-07-13 15:18           ` Vladimir Sementsov-Ogievskiy
2021-07-13 16:38             ` Stefan Hajnoczi
2021-07-15 12:35               ` Vladimir Sementsov-Ogievskiy
2021-07-15 13:29                 ` Stefan Hajnoczi
2021-07-16 15:23           ` Kevin Wolf
2021-07-19  9:29             ` Stefan Hajnoczi
2021-07-19 14:54               ` Kevin Wolf
2021-07-08 13:09 ` Stefan Hajnoczi
2021-07-12  8:42   ` Emanuele Giuseppe Esposito
2021-07-13 13:27     ` Stefan Hajnoczi

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