1419668 - MemoryBlockCache::mMaxBlocks doesn't change as buffer size grows

Status: RESOLVED FIXED

(Core :: Audio/Video: Playback, enhancement, P3)

Description

[JW Wang [:jwwang] [:jw_wang]]

https://searchfox.org/mozilla-central/rev/797c93d81fe446f78babf20894f0729f15f71ee6/dom/media/MemoryBlockCache.cpp#156

Found this bug while debugging bug 1418430 by playing http://23.253.41.15/ff/. The initial content length is 1000000 and buffer size is grew as more data comes in. However, mMaxBlocks is not changed and some blocks will be evicted for exceeding the max number of blocks.

This is not ideal. Since MemoryBlockCache is used only when the content length is smaller than MediaPrefs::MediaMemoryCacheMaxSize() * 1024, we should set mMaxBlocks according to the pref value.

Comment 1

[JW Wang [:jwwang] [:jw_wang]]

Attachment: Bug 1419668 - set mMaxBlocks according to MediaPrefs::MediaMemoryCacheMaxSize().

Since MemoryBlockCache is used only when the content length is smaller than
MediaPrefs::MediaMemoryCacheMaxSize() * 1024, we should set mMaxBlocks according
to the pref value to prevent blocks from being evicted unexpectedly.

Review commit: https://reviewboard.mozilla.org/r/202292/diff/#index_header
See other reviews: https://reviewboard.mozilla.org/r/202292/

Comment 2

[Benjamin Chen [:bechen]]

Comment on attachment 8931197 [details]
Bug 1419668 - set mMaxBlocks according to MediaPrefs::MediaMemoryCacheMaxSize().

https://reviewboard.mozilla.org/r/202292/#review207656

Comment 3

[Gerald Squelart (he/him) (not at Mozilla since 2022-09-15)]

Comment on attachment 8931197 [details]
Bug 1419668 - set mMaxBlocks according to MediaPrefs::MediaMemoryCacheMaxSize().

https://reviewboard.mozilla.org/r/202292/#review207996

Makes sense, thank you.

Comment 4

[JW Wang [:jwwang] [:jw_wang]]

Thanks for the reviews!

Comment 5

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/6724ad1ea301
set mMaxBlocks according to MediaPrefs::MediaMemoryCacheMaxSize(). r=bechen,gerald

Comment 6

[Arthur Iakab [arthur_iakab]]

https://hg.mozilla.org/mozilla-central/rev/6724ad1ea301