1710958 - [Wayland] [DMABUF] 7MB memory per content process wasted by loading Mesa early in startup

Status: RESOLVED FIXED

(Core :: Widget: Gtk, defect, P2)

Description

[Jed Davis [:jld] ⟨⏰|UTC-7⟩ ⟦he/him⟧]

When MOZ_ENABLE_WAYLAND=1 is set, we appear to use a lot more memory (measured as resident-unique in about:memory / Private_Dirty in procfs smaps) in each content process.

The total amount is about 9 MB; of that, about 2 MB is reported in heap-unclassified and goes away if the process is started in headless mode (i.e., if we don't call gtk_init; see also bug 1635451).

The remaining 7 MB appears to be entirely because we're loading Mesa early in startup; and it goes away (and Mesa isn't loaded) if LIBGL_ALWAYS_SOFTWARE is set in the environment, possibly as a side effect of using software WebRender instead of hardware. In particular, about 4.2 MB of that is because of libLLVM's relocations.

Here's where the problem is:

#0  __dlopen (file=0x7ffde8cc4400 "/usr/lib/x86_64-linux-gnu/dri/radeonsi_dri.so", mode=258) at dlopen.c:75
#1  0x00007f9564f1403e in  () at /lib/x86_64-linux-gnu/libgbm.so.1
#2  0x00007f9564f12b65 in  () at /lib/x86_64-linux-gnu/libgbm.so.1
#3  0x00007f9564f13418 in  () at /lib/x86_64-linux-gnu/libgbm.so.1
#4  0x00007f9564f115d7 in gbm_create_device () at /lib/x86_64-linux-gnu/libgbm.so.1
#5  0x00007f956e84ed6a in mozilla::widget::nsGbmLib::CreateDevice(int) (fd=-389266432) at /home/jld/src/gecko-dev/widget/gtk/DMABufLibWrapper.h:62
#6  0x00007f956e833cfc in mozilla::widget::nsDMABufDevice::Configure(nsTSubstring<char>&) (this=this@entry=0x7f9573211728 <mozilla::widget::GetDMABufDevice()::dmaBufDevice>, aFailureId=...)
    at /home/jld/src/gecko-dev/widget/gtk/DMABufLibWrapper.cpp:239
#7  0x00007f956e833a49 in mozilla::widget::nsDMABufDevice::IsDMABufEnabled() (this=this@entry=0x7f9573211728 <mozilla::widget::GetDMABufDevice()::dmaBufDevice>)
    at /home/jld/src/gecko-dev/widget/gtk/DMABufLibWrapper.cpp:257
#8  0x00007f956e8340f7 in mozilla::widget::nsDMABufDevice::IsDMABufWebGLEnabled() (this=0x7f9573211728 <mozilla::widget::GetDMABufDevice()::dmaBufDevice>)
    at /home/jld/src/gecko-dev/widget/gtk/DMABufLibWrapper.cpp:288
#9  0x00007f956c63f023 in gfxPlatformGtk::gfxPlatformGtk() (this=0x7f9564b15430) at /home/jld/src/gecko-dev/gfx/thebes/gfxPlatformGtk.cpp:123
#10 0x00007f956c63479f in gfxPlatform::Init() () at /home/jld/src/gecko-dev/gfx/thebes/gfxPlatform.cpp:913
#11 0x00007f956c634f41 in gfxPlatform::InitChild(mozilla::gfx::ContentDeviceData const&) (aData=...) at /home/jld/src/gecko-dev/gfx/thebes/gfxPlatform.cpp:496
#12 0x00007f956e407851 in mozilla::dom::ContentChild::InitGraphicsDeviceData(mozilla::gfx::ContentDeviceData const&) (this=<optimized out>, aData=...) at /home/jld/src/gecko-dev/dom/ipc/ContentChild.cpp:1201

Comment 1

[Martin Stránský [:stransky] (ni? me)]

We can use lazy initialization of
https://searchfox.org/mozilla-central/rev/2bc4e5cdf669cc9de3ed98e38be3e50a27b25332/gfx/thebes/gfxPlatformGtk.cpp#121
https://searchfox.org/mozilla-central/rev/2bc4e5cdf669cc9de3ed98e38be3e50a27b25332/gfx/thebes/gfxPlatformGtk.h#78

Comment 2

[Martin Stránský [:stransky] (ni? me)]

Attachment: Bug 1710958 [Linux] Delay DMABuf initialization when it's really needed, r?jhorak

Comment 3

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/98f55de0f9f5
[Linux] Delay DMABuf initialization when it's really needed, r=jhorak

Comment 4

[Atila Butkovits]

https://hg.mozilla.org/mozilla-central/rev/98f55de0f9f5