1513678 - Twice-reported memory allocations in StyleSheet code

Status: NEW

(Core :: CSS Parsing and Computation, defect, P3)

Description

[Kartikaya Gupta (email:[e-mail])]

+++ This bug was initially created as a clone of Bug #1513672 +++

I ran DMD today on a WR-enabled mac build to chase down bug 1491512 a bit more, and the DMD report told me about some twice-reported blocks. There is the entry below in StyleSheet code. Full log is attached to bug 1513672.

Twice-reported {
  1 block in heap block record 6 of 11
  256 bytes (248 requested / 8 slop)
  0.00% of the heap (0.00% cumulative)
  3.35% of twice-reported (89.10% cumulative)
  Allocated at {
    #01: replace_malloc(unsigned long) (DMD.cpp:1123, in libmozglue.dylib)
    #02: moz_xmalloc (mozalloc.cpp:69, in libmozglue.dylib)
    #03: mozilla::StyleSheet::StyleSheet(mozilla::css::SheetParsingMode, mozilla::CORSMode, mozilla::net::ReferrerPolicy, mozilla::dom::SRIMetadata const&) (mozalloc.h:131, in XUL)
    #04: mozilla::css::Loader::CreateSheet(nsIURI*, nsIContent*, nsIPrincipal*, mozilla::css::SheetParsingMode, mozilla::CORSMode, mozilla::net::ReferrerPolicy, nsTSubstring<char16_t> const&, bool, mozilla::css::StyleSheetState&, RefPtr<mozilla::StyleSheet>*) (RefPtr.h:54, in XUL)
    #05: mozilla::css::Loader::InternalLoadNonDocumentSheet(nsIURI*, bool, mozilla::css::SheetParsingMode, bool, nsIPrincipal*, mozilla::Encoding const*, RefPtr<mozilla::StyleSheet>*, nsICSSLoaderObserver*, mozilla::CORSMode, mozilla::net::ReferrerPolicy, nsTSubstring<char16_t> const&) (Loader.cpp:2193, in XUL)
    #06: mozilla::css::Loader::LoadSheet(nsIURI*, bool, nsIPrincipal*, mozilla::Encoding const*, nsICSSLoaderObserver*, mozilla::CORSMode, mozilla::net::ReferrerPolicy, nsTSubstring<char16_t> const&) (Loader.cpp:2155, in XUL)
    #07: nsXBLResourceLoader::LoadResources(nsIContent*) (nsXBLResourceLoader.cpp:132, in XUL)
    #08: nsXBLService::GetBinding(nsIContent*, nsIURI*, bool, nsIPrincipal*, bool*, nsXBLBinding**, nsTArray<nsCOMPtr<nsIURI> >&) (nsXBLPrototypeResources.cpp:48, in XUL)
  }
  Reported at {
    #01: mozilla::dmd::ReportHelper(void const*, bool) (DMD.cpp:425, in libmozglue.dylib)
    #02: CacheMallocSizeOf(void const*) (nsXULPrototypeCache.cpp:523, in XUL)
    #03: mozilla::StyleSheet::SizeOfIncludingThis(unsigned long (*)(void const*)) const (StyleSheet.cpp:322, in XUL)
    #04: mozilla::css::Loader::SizeOfIncludingThis(unsigned long (*)(void const*)) const (Loader.cpp:0, in XUL)
    #05: nsDocument::DocAddSizeOfExcludingThis(nsWindowSizes&) const (nsDocument.cpp:11104, in XUL)
    #06: nsXBLDocumentInfo::SizeOfIncludingThis(unsigned long (*)(void const*)) const (nsXBLDocumentInfo.cpp:310, in XUL)
    #07: nsXULPrototypeCache::CollectMemoryReports(nsIHandleReportCallback*, nsISupports*) (nsXULPrototypeCache.cpp:573, in XUL)
    #08: nsWindowMemoryReporter::CollectReports(nsIHandleReportCallback*, nsISupports*, bool) (nsWindowMemoryReporter.cpp:573, in XUL)
  }
  Reported again at {
    #01: mozilla::dmd::ReportHelper(void const*, bool) (DMD.cpp:425, in libmozglue.dylib)
    #02: CacheMallocSizeOf(void const*) (nsXULPrototypeCache.cpp:523, in XUL)
    #03: mozilla::StyleSheet::SizeOfIncludingThis(unsigned long (*)(void const*)) const (StyleSheet.cpp:322, in XUL)
    #04: nsXBLPrototypeResources::SizeOfIncludingThis(unsigned long (*)(void const*)) const (nsXBLPrototypeResources.cpp:175, in XUL)
    #05: nsXBLPrototypeBinding::SizeOfIncludingThis(unsigned long (*)(void const*)) const (nsXBLPrototypeBinding.cpp:1563, in XUL)
    #06: nsXBLDocumentInfo::SizeOfIncludingThis(unsigned long (*)(void const*)) const (nsXBLDocumentInfo.cpp:316, in XUL)
    #07: nsXULPrototypeCache::CollectMemoryReports(nsIHandleReportCallback*, nsISupports*) (nsXULPrototypeCache.cpp:573, in XUL)
    #08: nsWindowMemoryReporter::CollectReports(nsIHandleReportCallback*, nsISupports*, bool) (nsWindowMemoryReporter.cpp:573, in XUL)
  }
}

Comment 1

[Kartikaya Gupta (email:[e-mail])]

The full log has a couple more at the end of the "twice reported blocks" section

Comment 2

[Emilio Cobos Álvarez [:emilio]]

If this is the parent process, which I guess it is, I guess we're hitting multiple XBL stylesheets which are shared because of this cache:

https://searchfox.org/mozilla-central/rev/3160ddc1f0ab55d230c595366662c62950e5c785/layout/style/Loader.cpp#903