From: Markus Armbruster <armbru@redhat.com>
To: "Marc-André Lureau" <marcandre.lureau@gmail.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>, QEMU <qemu-devel@nongnu.org>,
Peter Xu <peterx@redhat.com>,
"Dr. David Alan Gilbert" <dgilbert@redhat.com>
Subject: Re: [Qemu-devel] [PATCH v2 2/6] monitor: accept chardev input from iothread
Date: Mon, 03 Dec 2018 10:29:39 +0100 [thread overview]
Message-ID: <8736rf6jr0.fsf@dusky.pond.sub.org> (raw)
In-Reply-To: <CAJ+F1CJQ0SGWnQvL7A8oYHCiuyv-2wS_78Aoeco2ZMLVpH9gLw@mail.gmail.com> ("Marc-André Lureau"'s message of "Mon, 3 Dec 2018 12:04:00 +0400")
Marc-André Lureau <marcandre.lureau@gmail.com> writes:
> Hi
>
> On Mon, Dec 3, 2018 at 11:26 AM Markus Armbruster <armbru@redhat.com> wrote:
>>
>> Marc-André Lureau <marcandre.lureau@redhat.com> writes:
>>
>> > Chardev backends may not handle safely IO events from concurrent
>> > threads.
>>
>> What exactly could go wrong? Or is this a well-known fact that doesn't
>> need further elaboration?
>
> chardev are not thread-safe. Only the write path is, since commit
> 9005b2a7589540a3733b3abdcfbccfe7746cd1a1.
Add this to your commit message? Your call.
>> "safely handle I/O events"
>>
>> > Better to wake up the chardev from the monitor IO thread if
>> > it's being used as the chardev context.
>> >
>> > Unify code paths by using a BH in all cases.
>> >
>> > Drop the now redundant aio_notify() call.
>> >
>> > Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
[...]
next prev parent reply other threads:[~2018-12-03 9:41 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-29 12:57 [Qemu-devel] [PATCH v2 0/6] monitor: misc fixes Marc-André Lureau
2018-10-29 12:57 ` [Qemu-devel] [PATCH v2 1/6] monitor: inline ambiguous helper functions Marc-André Lureau
2018-10-30 3:33 ` Peter Xu
2018-12-03 6:58 ` Markus Armbruster
2018-10-29 12:57 ` [Qemu-devel] [PATCH v2 2/6] monitor: accept chardev input from iothread Marc-André Lureau
2018-10-30 3:43 ` Peter Xu
2018-12-03 7:10 ` Markus Armbruster
2018-12-03 8:04 ` Marc-André Lureau
2018-12-03 9:29 ` Markus Armbruster [this message]
2018-10-29 12:57 ` [Qemu-devel] [PATCH v2 3/6] char: add a QEMU_CHAR_FEATURE_GCONTEXT flag Marc-André Lureau
2018-12-03 7:20 ` Markus Armbruster
2018-12-03 8:11 ` Marc-André Lureau
2018-10-29 12:57 ` [Qemu-devel] [PATCH v2 4/6] monitor: check if chardev can switch gcontext for OOB Marc-André Lureau
2018-12-03 8:23 ` Markus Armbruster
2018-12-03 8:44 ` Marc-André Lureau
2018-10-29 12:57 ` [Qemu-devel] [PATCH v2 5/6] monitor: prevent inserting new monitors after cleanup Marc-André Lureau
2018-10-30 5:42 ` Peter Xu
2018-12-03 8:59 ` Markus Armbruster
2018-12-03 9:55 ` Marc-André Lureau
2018-12-03 12:16 ` Markus Armbruster
2018-10-29 12:57 ` [Qemu-devel] [PATCH v2 6/6] monitor: avoid potential dead-lock when cleaning up Marc-André Lureau
2018-12-03 9:26 ` Markus Armbruster
2018-12-03 10:02 ` Marc-André Lureau
2018-12-03 12:17 ` Markus Armbruster
2018-10-30 5:48 ` [Qemu-devel] [PATCH v2 0/6] monitor: misc fixes Peter Xu
2018-10-30 8:06 ` Marc-André Lureau
2018-10-30 17:56 ` Markus Armbruster
2018-12-03 9:36 ` Markus Armbruster
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