1611437 - [meta] Simplify the GC after stencil lands

Status: RESOLVED FIXED

(Core :: JavaScript: GC, task, P3)

Description

[Jon Coppeard (:jonco)]

The stencil project (bug 1544117) will let us parse JS without allocating GC things. This will allow us to make a number of simplifications to the GC.

Comment 1

[Jon Coppeard (:jonco)]

Off the top of my head, we can do the following:

• use a single atoms table and remove the partitioning
• remove merging of realms/zones used by off-thread parsing
• remove suppression of atoms GC while off-thread parsing
• remove blocking off-thread parsing while atoms GC is active
• make HeapThreshold::bytes_ MainThreadData<>
• remove anywhere we wait for parse tasks to finish to avoid them creating GC things (e.g. runtime stats collection)

Comment 2

[Ted Campbell [:tcampbell]]

Bug 1662102 will add a pref to change the runtime behaviour. Once we are happy with that we can strip out all the machinery.

Comment 3

[Jon Coppeard (:jonco)]

Attachment: Bug 1611437 - Part 1: Remove support for allocating GC things from helper threads r?arai

This removes allocation paths that are no longer used.

Comment 4

[Jon Coppeard (:jonco)]

Attachment: Bug 1611437 - Part 2: Remove partitioning of the atoms table now this is no longer needed r?arai

This was added to improve performance when helper threads could alloate atoms
concurrently with the main thread.

Depends on D131779

Comment 5

[Jon Coppeard (:jonco)]

Attachment: Bug 1611437 - Part 3: Remove atom zone free lists from the context r?arai

This was used to allow concurrent allocation of atoms from more than one
thread.

Depends on D131780

Comment 6

[Jon Coppeard (:jonco)]

Attachment: Bug 1611437 - Part 4: Ensure various heap threshold data is only accessed from the main thread r?arai

Depends on D131781

Comment 7

[Jon Coppeard (:jonco)]

Attachment: Bug 1611437 - Part 5: Stop waiting for off-thread parsing when collecting memory information r?arai

Depends on D131782

Comment 8

[Jon Coppeard (:jonco)]

Attachment: Bug 1611437 - Part 6: Remove stale comment about off-thread parsing r?arai

Depends on D131783

Comment 9

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/3c8c8b37b18d
Part 1: Remove support for allocating GC things from helper threads r=arai
https://hg.mozilla.org/integration/autoland/rev/62fbe8c0f683
Part 2: Remove partitioning of the atoms table now this is no longer needed r=arai
https://hg.mozilla.org/integration/autoland/rev/e7b0599c0b81
Part 3: Remove atom zone free lists from the context r=arai
https://hg.mozilla.org/integration/autoland/rev/c0f1f59e9690
Part 4: Ensure various heap threshold data is only accessed from the main thread r=arai
https://hg.mozilla.org/integration/autoland/rev/0c714249d686
Part 5: Stop waiting for off-thread parsing when collecting memory information r=arai
https://hg.mozilla.org/integration/autoland/rev/6a70ca3a2229
Part 6: Remove stale comment about off-thread parsing r=arai

Comment 10

[Cosmin Sabou [:CosminS]]

https://hg.mozilla.org/mozilla-central/rev/3c8c8b37b18d
https://hg.mozilla.org/mozilla-central/rev/62fbe8c0f683
https://hg.mozilla.org/mozilla-central/rev/e7b0599c0b81
https://hg.mozilla.org/mozilla-central/rev/c0f1f59e9690
https://hg.mozilla.org/mozilla-central/rev/0c714249d686
https://hg.mozilla.org/mozilla-central/rev/6a70ca3a2229