1451568 - Over 100K of unreported string bundle memory loaded in content processes

Status: RESOLVED WORKSFORME

(Core :: Internationalization, defect, P3)

Description

[Eric Rahm [:erahm]]

DMD indicates there's over 100KB of unreported arena allocations related to string bundles in content processes [1]. We should at least update `nsStringBundleService` to report its `mBundleMap` [2]. It's also possible that there are other allocations outside of the cache that we should report as well.

It also seems like we should be able to share these bundles b/w processes rather than loading in each one.

[1] 

> Unreported {
>   50 blocks in heap block record 8 of 3,055
>   102,400 bytes (102,400 requested / 0 slop)
>   Individual block sizes: 2,048 x 50
>   0.39% of the heap (16.40% cumulative)
>   1.26% of unreported (52.63% cumulative)
>   Allocated at {
>     #01: mozilla::ArenaAllocator<2048ul, 4ul>::AllocateChunk(unsigned long) (/var/dev/erahm/mozilla-unified/obj-x86_64-pc-linux-gnu-clang-5-debug/dist/include/mozilla/ArenaAllocator.h:196)
>     #02: mozilla::ArenaAllocator<2048ul, 4ul>::InternalAllocate(unsigned long) (/var/dev/erahm/mozilla-unified/obj-x86_64-pc-linux-gnu-clang-5-debug/dist/include/mozilla/ArenaAllocator.h:230)
>     #03: nsPersistentProperties::SetStringProperty(nsTSubstring<char> const&, nsTSubstring<char16_t> const&, nsTSubstring<char16_t>&) (/var/dev/erahm/mozilla-unified/xpcom/ds/nsPersistentProperties.cpp:511)
>     #04: ~nsTSubstring (/var/dev/erahm/mozilla-unified/obj-x86_64-pc-linux-gnu-clang-5-debug/dist/include/nsTSubstring.h:77)
>     #05: nsPropertiesParser::ParseValueCharacter(char16_t, char16_t const*, char16_t const*&, nsTSubstring<char16_t>&) (/var/dev/erahm/mozilla-unified/xpcom/ds/nsPersistentProperties.cpp:211)
>     #06: nsPropertiesParser::ParseBuffer(char16_t const*, unsigned int) (/var/dev/erahm/mozilla-unified/xpcom/ds/nsPersistentProperties.cpp:404)
>     #07: nsPropertiesParser::SegmentWriter(nsIUnicharInputStream*, void*, char16_t const*, unsigned int, unsigned int, unsigned int*) (/var/dev/erahm/mozilla-unified/xpcom/ds/nsPersistentProperties.cpp:332)
>     #08: nsConverterInputStream::ReadSegments(nsresult (*)(nsIUnicharInputStream*, void*, char16_t const*, unsigned int, unsigned int, unsigned int*), void*, unsigned int, unsigned int*) (/var/dev/erahm/mozilla-unified/intl/uconv/nsConverterInputStream.cpp:139)
>     #09: nsPersistentProperties::Load(nsIInputStream*) (/var/dev/erahm/mozilla-unified/xpcom/ds/nsPersistentProperties.cpp:475)
>     #10: nsStringBundle::LoadProperties() (/var/dev/erahm/mozilla-unified/intl/strres/nsStringBundle.cpp:129)
>     #11: decltype (((*{parm#1}).*{parm#2})()) mozilla::detail::RunnableMethodArguments<>::applyImpl<nsStringBundle, nsresult (nsStringBundle::*)()>(nsStringBundle*, nsresult (nsStringBundle::*)(), mozilla::Tuple<>&, mozilla::IndexSequence<>) (/var/dev/erahm/mozilla-unified/obj-x86_64-pc-linux-gnu-clang-5-debug/dist/include/nsThreadUtils.h:1164)
>     #12: nsThread::ProcessNextEvent(bool, bool*) (/var/dev/erahm/mozilla-unified/xpcom/threads/nsThread.cpp:1100)
>     #13: NS_ProcessNextEvent(nsIThread*, bool) (/var/dev/erahm/mozilla-unified/xpcom/threads/nsThreadUtils.cpp:519)
>     #14: mozilla::ipc::MessagePump::Run(base::MessagePump::Delegate*) (/var/dev/erahm/mozilla-unified/ipc/glue/MessagePump.cpp:97)
>     #15: ~AutoRunState (/var/dev/erahm/mozilla-unified/ipc/chromium/src/base/message_loop.cc:599)
>     #16: nsBaseAppShell::Run() (/var/dev/erahm/mozilla-unified/widget/nsBaseAppShell.cpp:159)
>     #17: XRE_RunAppShell() (/var/dev/erahm/mozilla-unified/toolkit/xre/nsEmbedFunctions.cpp:893)
>     #18: mozilla::ipc::MessagePumpForChildProcess::Run(base::MessagePump::Delegate*) (/var/dev/erahm/mozilla-unified/ipc/glue/MessagePump.cpp:269)
>     #19: ~AutoRunState (/var/dev/erahm/mozilla-unified/ipc/chromium/src/base/message_loop.cc:599)
>     #20: nsAutoPtr<mozilla::ipc::ProcessChild>::operator->() const (/var/dev/erahm/mozilla-unified/obj-x86_64-pc-linux-gnu-clang-5-debug/dist/include/nsAutoPtr.h:199)
>   }
> }

[2] https://searchfox.org/mozilla-central/rev/a0665934fa05158a5a943d4c8b277465910c029c/intl/strres/nsStringBundleService.h#49

Comment 1

[Kris Maglione [:kmag]]

In bug 1463587, I'm adding a helper that makes it fairly easy to initialize a block of shared memory in the parent process, remap it as read-only, and then share it with all content processes.

We can probably re-use that to share parsed string bundles among content processes that need access to them. Would also probably have the nice side-effect of requiring them to be packed into a compact address space rather than split across a bunch of padded malloced blocks.

Comment 2

[Eric Rahm [:erahm]]

This memory is now reported and bug 1470365 took care of more effective sharing, I think we can close it.