--- Begin Message ---
|
Subject: |
[PATCH 1/2] autorevert: don't reuse existing watch descriptors |
|
Date: |
Sat, 14 Nov 2020 11:54:58 -0500 |
Previously, when enabling autorevert for a new buffer, we would search
the buffers already registered with autorevert to see if any of them
had the same filename.
This is very slow with a large number of buffers - with 1000, it takes
2 seconds on my system. This 2-second overhead is paid for every new
file opened.
But this is an unnecesary optimization; registering the same file
twice with file-notify has minimal or no overhead, depending on the
implementation.
In fact, file-notify has some baked-in overhead to support registering
the same file twice without problems. For example, inotify on Linux
returns the same inotify watch descriptor when the same file is
registered twice; file-notify adds an additional uniquifying id so
that all watch descriptors are unique in Emacs, even with inotify.
We can rely on file-notify's existing support for handling the same
file being registered twice. We don't need this slow and complex
logic.
With this code deleted, enabling autorevert for a new buffer is
essentially instant even with 1000 buffers.
---
lisp/autorevert.el | 29 +++++++----------------------
1 file changed, 7 insertions(+), 22 deletions(-)
diff --git a/lisp/autorevert.el b/lisp/autorevert.el
index 046ea2b5d6..d5bb75c2f1 100644
--- a/lisp/autorevert.el
+++ b/lisp/autorevert.el
@@ -650,30 +650,15 @@ will use an up-to-date value of `auto-revert-interval'."
(string-match auto-revert-notify-exclude-dir-regexp
(expand-file-name default-directory))
(file-symlink-p (or buffer-file-name default-directory)))
- ;; Check, whether this has been activated already.
(let ((file (if buffer-file-name
(expand-file-name buffer-file-name default-directory)
(expand-file-name default-directory))))
- (maphash
- (lambda (key _value)
- (when (and
- (file-notify-valid-p key)
- (equal (file-notify--watch-absolute-filename
- (gethash key file-notify-descriptors))
- (directory-file-name file))
- (equal (file-notify--watch-callback
- (gethash key file-notify-descriptors))
- 'auto-revert-notify-handler))
- (setq auto-revert-notify-watch-descriptor key)))
- auto-revert--buffers-by-watch-descriptor)
- ;; Create a new watch if needed.
- (unless auto-revert-notify-watch-descriptor
- (setq auto-revert-notify-watch-descriptor
- (ignore-errors
- (file-notify-add-watch
- file
- (if buffer-file-name '(change attribute-change) '(change))
- 'auto-revert-notify-handler))))
+ (setq auto-revert-notify-watch-descriptor
+ (ignore-errors
+ (file-notify-add-watch
+ file
+ (if buffer-file-name '(change attribute-change) '(change))
+ 'auto-revert-notify-handler))))
(when auto-revert-notify-watch-descriptor
(setq auto-revert-notify-modified-p t)
(puthash
@@ -682,7 +667,7 @@ will use an up-to-date value of `auto-revert-interval'."
(gethash auto-revert-notify-watch-descriptor
auto-revert--buffers-by-watch-descriptor))
auto-revert--buffers-by-watch-descriptor)
- (add-hook 'kill-buffer-hook #'auto-revert-notify-rm-watch nil t)))))
+ (add-hook 'kill-buffer-hook #'auto-revert-notify-rm-watch nil t))))
;; If we have file notifications, we want to update the auto-revert buffers
;; immediately when a notification occurs. Since file updates can happen very
--
2.28.0
--- End Message ---
--- Begin Message ---
|
Subject: |
Re: bug#44638: [PATCH 1/2] autorevert: don't reuse existing watch descriptors |
|
Date: |
Thu, 03 Dec 2020 16:01:29 +0100 |
|
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/28.0.50 (gnu/linux) |
Michael Albinus <michael.albinus@gmx.de> writes:
> Eli Zaretskii <eliz@gnu.org> writes:
>
>>> > auto-revert-test07-auto-revert-several-buffers succeeds. Running the
>>> > entire test finds 2 failures:
>>> >
>>> > 2 unexpected results:
>>> > FAILED auto-revert-test04-auto-revert-mode-dired
>>> > FAILED auto-revert-test05-global-notify
>>> >
>>> > Let me know if I can help you more.
>>>
>>> Well, if the same errors happen also w/o that patch, I believe we are
>>> safe to install the patch in master.
>>
>> Yes, I think those tests always failed for me.
>
> Good, so I will install patch 1/2 in master. Likely tomorrow.
Done, closing the bug.
Best regards, Michael.
--- End Message ---