Blocking preference write causes us to re-enter event loop

RESOLVED FIXED in Firefox 57

Status

()

Product:
Core
Component:
Preferences: Backend
Status:
RESOLVED FIXED
Reported:
a year ago
Modified:
a year ago

People

(Reporter: milan, Assigned: milan)

Tracking

(Blocks: 1 bug)

Version:
unspecified
Target:
mozilla57
Platform:
All
Unspecified
Points:
---
Dependency tree / graph
Duplicates:
1387242

Firefox Tracking Flags

(firefox56 unaffected, firefox57 fixed)

Details

Attachments

(1 attachment)

Bug 1388464: Use SyncRunnable instead of DISPATCH_SYNC to actually block the main thread during the blocking preference file write.
59 bytes, text/x-review-board-request
smaug
: review+
Details
(Assignee)

Description

•
a year ago 
See 1386263.  The goal of the sync pref file save off the main thread was to block the main thread until the work is done, not to allow an event loop to spin which is allowed to process other events.
Assignee: nobody → milan
See Also: → bug 1386263, bug 789945
 (Assignee)

Comment 1

•
a year ago 
We are using nsIEventTarget::Dispatch with DISPATCH_SYNC flag.  We should have been using SyncRunnable::DispatchToThread instead.
Comment hidden (mozreview-request)

Comment 4

•
a year ago
mozreview-review 
Comment on attachment 8895073 [details]
Bug 1388464: Use SyncRunnable instead of DISPATCH_SYNC to actually block the main thread during the blocking preference file write.

https://reviewboard.mozilla.org/r/166198/#review171466
Attachment #8895073 - Flags: review?(bugs) → review+
 (Assignee)

Comment 6

•
a year ago 
NI Benjamin just to make sure he's seen this.
Flags: needinfo?(benjamin)

Comment 7

•
a year ago 
Pushed by msreckovic@mozilla.com:
https://hg.mozilla.org/integration/autoland/rev/6ffe8a4a92c7
Use SyncRunnable instead of DISPATCH_SYNC to actually block the main thread during the blocking preference file write.  r=smaug

Comment 8

•
a year ago
bugherder 
https://hg.mozilla.org/mozilla-central/rev/6ffe8a4a92c7
Status: NEW → RESOLVED
Last Resolved: a year ago
status-firefox57: --- → fixed
Resolution: --- → FIXED
Target Milestone: --- → mozilla57

Updated

•
a year ago
Flags: needinfo?(benjamin)

Comment 9

•
a year ago 
Didn't this code land for 56? I think this needs an uplift.
status-firefox56: --- → ?
tracking-firefox56: --- → ?
Flags: needinfo?(milan)
 (Assignee)

Comment 10

•
a year ago 
Indeed, but 56 has it disabled through a preference, so we shouldn't hit this codepath.  But, yes, if we want to enable the off main thread preference write and on pref change auto save, we'd need this patch as well.
Flags: needinfo?(milan)

Comment 11

•
a year ago 
Track 56+ in case we will enable the pref.
tracking-firefox56: ? → +
 (Assignee)

Comment 12

•
a year ago 
This is still disabled by pref in 56, so 56 is unaffected.
status-firefox56: ? → unaffected
tracking-firefox56: + → ---
Duplicate of this bug: 1387242
You need to log in before you can comment on or make changes to this bug.