Read this as a first step. It's the easiest first step I could think of to
both reduce the quantity of stuff we serialize and ship to the worker as
well as to spread it out over multiple messages.
Anyway, the motivation is pretty simple. Taking a look at a session store
file on disk, a giant chunk of it is base64 encoded tab icons. I suspect
that in many cases these are not distinct. For my session store it's about
90% the same repeated searchfox icon over and over.
So what I did was I changed the "image" property of the tab to be a reference
into a deduplicated cache of objects (in this case strings). Whenever the tab
icon changes, we drop a reference to its cache entry and add a reference to a
new or existing entry. Each time a cache entry is added or deleted, we send
a message to the worker to update its own copy of the cache. This does
represent a memory hit, since the cache is maintained on the worker as well as
the main thread, but I think it's going to be minor, and it's only in one
process. Given the deduplication there is the possibility of an overall
reduction in memory use? This needs more testing.
Once it comes time to write the session data to disk, we send the payload with
"image" entries referencing IDs in the cache. When the worker gets the message
to write, it adds its internal cache to the object, which it then serializes
to JSON and writes to disk as usual.
When reading the data off disk, we take the cache items that had been written
and we slowly populate the worker's internal cache with them (to not overload
during startup with a giant message). And when populating tab icons of tabs in
the tab strip, we look up the image in the main thread copy of the cache. Also,
if we cannot find the entry, we assume that the image is just the raw
representation of the image. This ensures that we interpret a sessionstore file
from prior to this patch correctly.
Additionally, since we have the cache duplicated on both threads, if the worker
gets terminated for some reason, we rehydrate it with the snapshot of the cache
from when we noticed it was a problem.
I suspect some tests will need to be updated, or maybe many tests. However I
wanted to throw this patch past someone with more knowledge of the session
store's inner workings before throwing a bunch of time at that.
Differential Revision: https://phabricator.services.mozilla.com/D114196
***
Bug 1514594: Part 3a - Change ChromeUtils.import to return an exports object; not pollute global. r=mccr8
This changes the behavior of ChromeUtils.import() to return an exports object,
rather than a module global, in all cases except when `null` is passed as a
second argument, and changes the default behavior not to pollute the global
scope with the module's exports. Thus, the following code written for the old
model:
ChromeUtils.import("resource://gre/modules/Services.jsm");
is approximately the same as the following, in the new model:
var {Services} = ChromeUtils.import("resource://gre/modules/Services.jsm");
Since the two behaviors are mutually incompatible, this patch will land with a
scripted rewrite to update all existing callers to use the new model rather
than the old.
***
Bug 1514594: Part 3b - Mass rewrite all JS code to use the new ChromeUtils.import API. rs=Gijs
This was done using the followng script:
https://bitbucket.org/kmaglione/m-c-rewrites/src/tip/processors/cu-import-exports.jsm
***
Bug 1514594: Part 3c - Update ESLint plugin for ChromeUtils.import API changes. r=Standard8
Differential Revision: https://phabricator.services.mozilla.com/D16747
***
Bug 1514594: Part 3d - Remove/fix hundreds of duplicate imports from sync tests. r=Gijs
Differential Revision: https://phabricator.services.mozilla.com/D16748
***
Bug 1514594: Part 3e - Remove no-op ChromeUtils.import() calls. r=Gijs
Differential Revision: https://phabricator.services.mozilla.com/D16749
***
Bug 1514594: Part 3f.1 - Cleanup various test corner cases after mass rewrite. r=Gijs
***
Bug 1514594: Part 3f.2 - Cleanup various non-test corner cases after mass rewrite. r=Gijs
Differential Revision: https://phabricator.services.mozilla.com/D16750
We've been able to validate that the sessionstore worker restarts, as implemented
in bug 1402267, are working as expected and that worker threads are indeed _not_
infallible during the main process' lifetime.
MozReview-Commit-ID: Le8AJhlWMn8
These issues were previously ignored due to the nature of our global import
rules. They need to be fixed before that rule can be updated.
MozReview-Commit-ID: DCChktTc5TW
Importing this object is unnecessary after the updates to the WebIDL console from Bug 1425574
and the follow-ups blocking Bug 1430810. There are still callers that access Console.jsm
to create custom ConsoleAPI objects, but those will be handled separately.
MozReview-Commit-ID: 9ojFxtkpPId
This patch was autogenerated by my decomponents.py
It covers almost every file with the extension js, jsm, html, py,
xhtml, or xul.
It removes blank lines after removed lines, when the removed lines are
preceded by either blank lines or the start of a new block. The "start
of a new block" is defined fairly hackily: either the line starts with
//, ends with */, ends with {, <
