2061763 - Make the buffer allocator use a single set of available lists for nursery/tenured chunks

Status: RESOLVED FIXED

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

Description

[Jon Coppeard (:jonco)]

Currently there are separate sets of lists for available nursery and tenured chunks (available means they have free space but we aren't currently using them for allocation). These lists are populated with chunks that have been swept after minor and major GC. Since semispace nursery is not yet in use the available list for mixed chunks (those containing nursery allocations) will always be empty.

Since there is one list per size class and there are ~16 size classes this is a bit wasteful. This will also be more of a problem later if we want to add more size classes.

We can improve this by using a single list per size class and partitioning it so all mixed chunks come before any tenured chunks.

Comment 1

[Jon Coppeard (:jonco)]

Attachment: Bug 2061763 - Part 1: Rename main chunks lists to 'current' (vs existing 'available' lists) r?sfink

Not a functional change but renames the current lists (previously just
mixedChunks and tenuredChunks) to distinguish them from the available lists.

Comment 2

[Jon Coppeard (:jonco)]

Attachment: Bug 2061763 - Part 2: Add SlimLinkedList::removeRange r?sfink

Comment 3

[Jon Coppeard (:jonco)]

Attachment: Bug 2061763 - Part 3: Use a single set of lists for available chunks and partition them by mixed/tenured kind r?sfink

If semispace nursery is not in use then everything live is tenured by minor
collection and the available mixed chunks lists will always be empty.

This changes this implementation of the avilable lists to use a single list for
both mixed and tenured chunks, arranged so that all mixed chunks come before
any tenured chunks.

Comment 4

[Pulsebot]

Pushed by [e-mail]:
https://github.com/mozilla-firefox/firefox/commit/4cd85d8cff3d
https://hg.mozilla.org/integration/autoland/rev/663240998dcf
Part 1: Rename main chunks lists to 'current' (vs existing 'available' lists) r=sfink
https://github.com/mozilla-firefox/firefox/commit/1844d0041418
https://hg.mozilla.org/integration/autoland/rev/1d5efc6ea410
Part 2: Add SlimLinkedList::removeRange r=sfink
https://github.com/mozilla-firefox/firefox/commit/f22c487927fd
https://hg.mozilla.org/integration/autoland/rev/1782606c72d2
Part 3: Use a single set of lists for available chunks and partition them by mixed/tenured kind r=sfink

Comment 5

[Sandor Molnar[:smolnar]]

https://hg.mozilla.org/mozilla-central/rev/663240998dcf
https://hg.mozilla.org/mozilla-central/rev/1d5efc6ea410
https://hg.mozilla.org/mozilla-central/rev/1782606c72d2