Jemalloc 4 purges dirty pages regularly during free() when the ratio of dirty
pages compared to active pages is higher than 1 << lg_dirty_mult. We set
lg_dirty_mult in jemalloc_config to limit RSS usage, but it also has an impact
on performance.
So instead of enforcing a high ratio to force more pages being purged, we keep
jemalloc's default ratio of 8, and force a regular purge of all dirty pages,
after cycle collection.
Keeping jemalloc's default ratio avoids cycle-collection-triggered purge to
have to go through really all dirty pages when there are a lot, in which case
the normal jemalloc purge during free() will already have kicked in. It also
takes care of everything that doesn't run the cycle collector still having
a level of purge, like plugins in the plugin-container.
At the same time, since jemalloc_purge_freed_pages does nothing with jemalloc 4,
repurpose the MEMORY_FREE_PURGED_PAGES_MS telemetry probe to track the time
spent in this cycle-collector-triggered purge.
Per the product discussion, the Notification API should be disabled in
ServiceWorker in release builds for 42 since the UX isn't great [1].
The aim is to release in 44.
Apologies for the code duplication for pref checking in Notification and
ServiceWorkerRegistration. There isn't a easy way to get
ServiceWorkerRegistration's generated binding to include Notification.h without
having an attribute/method that uses Notification.
[1]: https://mana.mozilla.org/wiki/x/TgAJAw
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extra : commitid : 5dtc2E63kuM
extra : rebase_source : 4265dcd154462aa4f3b915e9e898fe7b82bf9afc
This is motivated by three separate but related problems:
1. Our concept of recursion depth is broken for things that run from AfterProcessNextEvent observers (e.g. Promises). We decrement the recursionDepth counter before firing observers, so a Promise callback running at the lowest event loop depth has a recursion depth of 0 (whereas a regular nsIRunnable would be 1). This is a problem because it's impossible to distinguish a Promise running after a sync XHR's onreadystatechange handler from a top-level event (since the former runs with depth 2 - 1 = 1, and the latter runs with just 1).
2. The nsIThreadObserver mechanism that is used by a lot of code to run "after" the current event is a poor fit for anything that runs script. First, the order the observers fire in is the order they were added, not anything fixed by spec. Additionally, running script can cause the event loop to spin, which is a big source of pain here (bholley has some nasty bug caused by this).
3. We run Promises from different points in the code for workers and main thread. The latter runs from XPConnect's nsIThreadObserver callbacks, while the former runs from a hardcoded call to run Promises in the worker event loop. What workers do is particularly problematic because it means we can't get the right recursion depth no matter what we do to nsThread.
The solve this, this patch does the following:
1. Consolidate some handling of microtasks and all handling of stable state from appshell and WorkerPrivate into CycleCollectedJSRuntime.
2. Make the recursionDepth counter only available to CycleCollectedJSRuntime (and its consumers) and remove it from the nsIThreadInternal and nsIThreadObserver APIs.
3. Adjust the recursionDepth counter so that microtasks run with the recursionDepth of the task they are associated with.
4. Introduce the concept of metastable state to replace appshell's RunBeforeNextEvent. Metastable state is reached after every microtask or task is completed. This provides the semantics that bent and I want for IndexedDB, where transactions autocommit at the end of a microtask and do not "spill" from one microtask into a subsequent microtask. This differs from appshell's RunBeforeNextEvent in two ways:
a) It fires between microtasks, which was the motivation for starting this.
b) It no longer ensures that we're at the same event loop depth in the native event queue. bent decided we don't care about this.
5. Reorder stable state to happen after microtasks such as Promises, per HTML. Right now we call the regular thread observers, including appshell, before the main thread observer (XPConnect), so stable state tasks happen before microtasks.
Currently we don't check the dom.push.enabled pref in some cases for
some of these interfaces. This patch unifies how all of these
interfaces are exposed to Window, Worker, and ServiceWorker.
Currently we don't check the dom.push.enabled pref in some cases for
some of these interfaces. This patch unifies how all of these
interfaces are exposed to Window, Worker, and ServiceWorker.
Does not implement the Service Worker API - https://notifications.spec.whatwg.org/#service-worker-api
***
Folded:
Bug 916893 - Better ownership model. r=khuey
Fix for bug found by ASan where we were touching the NotificationFeature after releasing it.
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extra : transplant_source : %3C%09F%99%CASF%1A%25%89X%D9%8C%0B%FAu%9D%27%E8w
Does not implement the Service Worker API - https://notifications.spec.whatwg.org/#service-worker-api
***
Folded:
Bug 916893 - Better ownership model. r=khuey
Fix for bug found by ASan where we were touching the NotificationFeature after releasing it.
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extra : rebase_source : 7522a4a51fda41726e7cf26b61fbf535c260fab3
Morris Tseng
Eddy Bruel
Wes Kocher
Catalin Badea
Benjamin Bouvier
Andrea Marchesini
Mike Hommey
Nikhil Marathe
Kyle Huey
Ehsan Akhgari
Francisco Jordano
Ryan VanderMeulen
Randell Jesup
Dragana Damjanovic
Ben Kelly
Birunthan Mohanathas
Paolo Amadini
Jose Antonio Olivera Ortega
Eddy Bruël
Ben Turner