From: Akira Kyle <ak@akirakyle.com>
To: Eli Zaretskii <eliz@gnu.org>
Cc: Philipp Stephani <p.stephani2@gmail.com>,
emacs-devel@gnu.org, yyoncho <yyoncho@gmail.com>,
Stefan Monnier <monnier@iro.umontreal.ca>,
all_but_last@163.com
Subject: Re: "Asynchronous Requests from Emacs Dynamic Modules"
Date: Sat, 31 Oct 2020 13:25:58 -0600 [thread overview]
Message-ID: <86ft5ufb95.fsf@akirakyle.com> (raw)
In-Reply-To: <83h7qahe03.fsf@gnu.org>
On Sat, Oct 31, 2020 at 04:43 AM, Eli Zaretskii <eliz@gnu.org>
wrote:
>> That is unfortunate. I was assuming that at least thread
>> primitives can be made thread-safe.
>
> They are thread-safe, but they rely on strict discipline of
> having
> one, and only one, Lisp thread active at any given time. IOW,
> the
> mechanism that switches threads is not "thread-safe".
To summarize so far, I see three different ways of tackling this:
1) Chris Wellon's solution in the article I linked using the
SIGUSR1 signal which Emacs handles in the event queue notify the
running Lisp Thread that it should call back into module
functions. This idea could be expanded to allow modules to define
their own events and lisp handlers that will respond to them.
2) Stefan's and Philipp's proposal of using the process interface
with file descriptors to pipes and perhaps `process-filter` to
notify the Lisp Thread that it should call back into the module
functions.
3) yyoncho's proposal to use the lisp threading interface,
specifically condition variables to allow dynamic modules to
`condition-notify`.
I see advantages and disadvantages to each. I think the most
natural solution would be a dynamic module interface that allows
grabbing and releasing Lisp's global thread lock. I think this
would simplify writing dynamic module functions which could
potentially cause Emacs to hang as it wouldn't require module
authors to think about the lisp machinery to figure out what
module function with what state to call back into when it needs to
get its result back into lisp land. The way such an interface is
implemented could be with any of the above mechanisms or something
else.
next prev parent reply other threads:[~2020-10-31 19:25 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-30 21:35 "Asynchronous Requests from Emacs Dynamic Modules" Akira Kyle
2020-10-30 22:39 ` Stefan Monnier
2020-10-31 3:18 ` Zhu Zihao
2020-10-31 7:45 ` Eli Zaretskii
2020-10-31 8:02 ` yyoncho
2020-10-31 9:13 ` Eli Zaretskii
2020-10-31 9:45 ` yyoncho
2020-10-31 10:43 ` Eli Zaretskii
2020-10-31 19:25 ` Akira Kyle [this message]
2020-10-31 20:18 ` Eli Zaretskii
2020-11-01 0:14 ` Akira Kyle
2020-11-01 18:28 ` Eli Zaretskii
2020-11-01 20:15 ` Akira Kyle
2020-11-01 20:51 ` async-await (was: Re: "Asynchronous Requests from Emacs Dynamic Modules") Philipp Stephani
2020-11-02 15:22 ` "Asynchronous Requests from Emacs Dynamic Modules" Eli Zaretskii
2020-10-31 7:36 ` Philipp Stephani
2020-10-31 12:49 ` Stefan Monnier
2020-11-01 20:18 ` Akira Kyle
2020-11-01 20:32 ` Philipp Stephani
2020-11-20 15:54 ` Zhu Zihao
2020-11-20 16:04 ` Robert Pluim
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