Build Chromium with thinlto fails: mmap failed: Cannot allocate memory

[blackteahamburger]

I used a patch similar to #336 (comment) to try to build Chromium with thinlto with mold. All is fine except the final link:

[48401/48401] "python3.13" "../../build/toolchain/gcc_link_wrapper.py" --output="./chrome" -- x86_64-pc-linux-gnu-clang++-19 -Wl,--version-script=../../build/linux/chrome.map -fuse-ld=mold -Wl,--build-id=sha1 -fPIC -Wl,-z,noexecstack -Wl,-z,relro -Wl,-z,now -Wl,--icf=all -Wl,--color-diagnostics -Wl,--thinlto-cache-dir=thinlto-cache -Wl,--thinlto-cache-policy=cache_size=10\%:cache_size_bytes=40g:cache_size_files=100000 -flto=thin -Wl,--thinlto-jobs=all -fwhole-program-vtables -Wl,--undefined-version -no-canonical-prefixes -Wl,-z,defs -Wl,--as-needed -rdynamic -pie -Wl,--disable-new-dtags -Wl,--lto-O2 -Wl,-O1 -Wl,--as-needed -Wl,-z,pack-relative-relocs -fuse-ld=mold -Wl,--lto-O3 -march=native -O3 -fno-semantic-interposition -pipe -Wl,--thread-count=4 -Wl,--thinlto-jobs=4 -o "./chrome" -Wl,--start-group @"./chrome.rsp" -Wl,--end-group   -latomic -ldl -lpthread -lrt -lgmodule-2.0 -lgobject-2.0 -lgthread-2.0 -lglib-2.0 -licui18n -licuuc -lsmime3 -lnss3 -lnssutil3 -lplds4 -lplc4 -lnspr4 -latk-bridge-2.0 -latk-1.0 -lgio-2.0 -lfontconfig -ldbus-1 -ljsoncpp -lz -ldouble-conversion -lresolv -lzstd -lexpat -lpng16 -lwebpdemux -lwebpmux -lwebp -lfreetype -ljpeg -lharfbuzz-subset -lharfbuzz -lopus -lX11 -lXcomposite -lXdamage -lXext -lXfixes -lXrender -lXrandr -lXtst -lcrc32c -lsnappy -lxcb -lxkbcommon -lgbm -lXi -lpci -ludev -lpangocairo-1.0 -lpango-1.0 -lcairo -lasound -lFLAC -lavformat -lavcodec -lavutil -lxml2 -latspi -lminizip -lstdc++ -lxslt -lwoff2dec -lbrotlidec -lxshmfence -llcms2 -llcms2_fast_float -llcms2_threaded -lopenjp2 -lpng -Wl,--start-group  -Wl,--end-group 
FAILED: chrome 
"python3.13" "../../build/toolchain/gcc_link_wrapper.py" --output="./chrome" -- x86_64-pc-linux-gnu-clang++-19 -Wl,--version-script=../../build/linux/chrome.map -fuse-ld=mold -Wl,--build-id=sha1 -fPIC -Wl,-z,noexecstack -Wl,-z,relro -Wl,-z,now -Wl,--icf=all -Wl,--color-diagnostics -Wl,--thinlto-cache-dir=thinlto-cache -Wl,--thinlto-cache-policy=cache_size=10\%:cache_size_bytes=40g:cache_size_files=100000 -flto=thin -Wl,--thinlto-jobs=all -fwhole-program-vtables -Wl,--undefined-version -no-canonical-prefixes -Wl,-z,defs -Wl,--as-needed -rdynamic -pie -Wl,--disable-new-dtags -Wl,--lto-O2 -Wl,-O1 -Wl,--as-needed -Wl,-z,pack-relative-relocs -fuse-ld=mold -Wl,--lto-O3 -march=native -O3 -fno-semantic-interposition -pipe -Wl,--thread-count=4 -Wl,--thinlto-jobs=4 -o "./chrome" -Wl,--start-group @"./chrome.rsp" -Wl,--end-group   -latomic -ldl -lpthread -lrt -lgmodule-2.0 -lgobject-2.0 -lgthread-2.0 -lglib-2.0 -licui18n -licuuc -lsmime3 -lnss3 -lnssutil3 -lplds4 -lplc4 -lnspr4 -latk-bridge-2.0 -latk-1.0 -lgio-2.0 -lfontconfig -ldbus-1 -ljsoncpp -lz -ldouble-conversion -lresolv -lzstd -lexpat -lpng16 -lwebpdemux -lwebpmux -lwebp -lfreetype -ljpeg -lharfbuzz-subset -lharfbuzz -lopus -lX11 -lXcomposite -lXdamage -lXext -lXfixes -lXrender -lXrandr -lXtst -lcrc32c -lsnappy -lxcb -lxkbcommon -lgbm -lXi -lpci -ludev -lpangocairo-1.0 -lpango-1.0 -lcairo -lasound -lFLAC -lavformat -lavcodec -lavutil -lxml2 -latspi -lminizip -lstdc++ -lxslt -lwoff2dec -lbrotlidec -lxshmfence -llcms2 -llcms2_fast_float -llcms2_threaded -lopenjp2 -lpng -Wl,--start-group  -Wl,--end-group 
mold: fatal: /var/tmp/portage/www-client/ungoogled-chromium-132.0.6834.159_p1-r1/temp/lto-llvm-014f27.o: mmap failed: Cannot allocate memory
x86_64-pc-linux-gnu-clang++-19: error: linker command failed with exit code 1 (use -v to see invocation)
ninja: build stopped: subcommand failed.

I set MOLD_JOBS=1, -Wl,--thread-count=4 and -Wl,--thinlto-jobs=4 but still failed. When it fails I notice that my memory usage is less than half.

After some search, I found "Having plenty of memory is not enough. Hardware requires each page be contiguous range of physical memory aligned by page size." I already have kernel config CONFIG_TRANSPARENT_HUGEPAGE_ALWAYS=y. Any suggestions to eliminate the error? Or is this an issue with the mold itself?

[rui314]

Can you build it with lld?

It looks like an mmap(2) failure caused the issue. Did you set a limitation of the virtual address space or something with ulimit?