src: add percentage support to --max-old-space-size #59082

Asaf-Federman · 2025-07-16T07:45:02Z

This commit adds support for specifying --max-old-space-size as a percentage of system memory, in addition to the existing MB format. A new HandleMaxOldSpaceSizePercentage method parses percentage values, validates that they are within the 0-100% range, and provides clear error messages for invalid input. The heap size is now calculated based on available system memory when a percentage is used.

Test coverage has been added for both valid and invalid cases. Documentation and the JSON schema for CLI options have been updated with examples for both formats.

Refs: #57447

nodejs-github-bot · 2025-07-16T07:45:07Z

Review requested:

@nodejs/config
@nodejs/startup

legendecas

I'm -1 on re-interpreting a V8 flag with different semantic in Node.js as it could lead to confusions. I'd be open to a new flag though.

doc/api/cli.md

Asaf-Federman · 2025-07-16T09:30:29Z

I'm -1 on re-interpreting a V8 flag with different semantic in Node.js as it could lead to confusions. I'd be open to a new flag though.

Isn't it dangerous having two different flags for the same underlying v8 option?
If user will specify both flags, which one will take precedence? Or should we throw exception in this case?

legendecas · 2025-07-16T10:55:46Z

We can define that a flag will alway take precedence over another, e.g. --max-old-space-size-percentage always override --max-old-space-size. I'd only consider it is harmful if a flag conditionally take precedence.

See node --v8-options:

  --max-heap-size (max size of the heap (in Mbytes) both max_semi_space_size and max_old_space_size take precedence. All three flags cannot be specified at the same time.)

It could also be a good practice to abort if both flags are set. When all three heap size options --max-heap-size=20 --max-old-space-size=20 --max-semi-space-size=20 are set at the same time, V8 aborts.

And, like mentioned, there are three heap size options. I'm -0 on introduce 3 new flags on each of them, TBH.

Asaf-Federman · 2025-07-16T11:01:43Z

We can define that a flag will alway take precedence over another, e.g. --max-old-space-size-percentage always override --max-old-space-size. I'd only consider it is harmful if a flag conditionally take precedence.

See node --v8-options:
  --max-heap-size (max size of the heap (in Mbytes) both max_semi_space_size and max_old_space_size take precedence. All three flags cannot be specified at the same time.)
It could also be a good practice to abort if both flags are set. When all three heap size options --max-heap-size=20 --max-old-space-size=20 --max-semi-space-size=20 are set at the same time, V8 aborts.

And, like mentioned, there are three heap size options. I'm -0 on introduce 3 new flags on each of them, TBH.

As long as there's an agreed way of action, I don't mind changing the implementation

jasnell · 2025-07-18T15:50:18Z

Another approach would be to see if v8 would accept a patch adding this as an additional v8 flag... I can see it potentially being generically useful for all v8 users

jasnell · 2025-07-18T16:05:13Z

src/node_options.cc

+
+  // Parse the percentage value
+  char* end_ptr;
+  double percentage =


Why double? It's likely best to just allow integer values here between 0 and 100. Not critical, of course, I'd just find it a bit cleaner

Why double? It's likely best to just allow integer values here between 0 and 100. Not critical, of course, I'd just find it a bit cleaner

Should this be an integer, or would a float provide better flexibility for nodes with a large amount of memory?

Really depends on how granular we want it to be. Personally I'd be fine with integer and just not worry about fractional percentages but I'd be interested in what others think

if it was a breaking change I would agree, but this is a new feature, why not support more usecases even if they are rare?

Asaf-Federman · 2025-07-18T16:30:26Z

Another approach would be to see if v8 would accept a patch adding this as an additional v8 flag... I can see it potentially being generically useful for all v8 users

#57447

I have already approached the V8 team, and they have indicated that a contribution to the Node.js project would be more appropriate.
Please see here

staskorz · 2025-07-20T14:14:55Z

This will be a huge help, appreciate you working on this!

codecov · 2025-07-21T14:55:56Z

Codecov Report

❌ Patch coverage is 89.28571% with 3 lines in your changes missing coverage. Please review.
✅ Project coverage is 90.06%. Comparing base (6bb08f7) to head (8e5f5ea).
⚠️ Report is 395 commits behind head on main.

Files with missing lines	Patch %	Lines
src/node_options.cc	86.36%	1 Missing and 2 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #59082      +/-   ##
==========================================
+ Coverage   90.04%   90.06%   +0.02%     
==========================================
  Files         648      648              
  Lines      190978   191006      +28     
  Branches    37434    37438       +4     
==========================================
+ Hits       171964   172028      +64     
+ Misses      11641    11606      -35     
+ Partials     7373     7372       -1

Files with missing lines	Coverage Δ
src/node.cc	`74.93% <100.00%> (+0.20%)`	⬆️
src/node_options.h	`97.87% <ø> (ø)`
src/node_options.cc	`84.65% <86.36%> (+0.04%)`	⬆️

... and 33 files with indirect coverage changes

🚀 New features to boost your workflow:

❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
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doc/api/cli.md

This commit adds support for specifying --max-old-space-size as a percentage of system memory, in addition to the existing MB format. A new HandleMaxOldSpaceSizePercentage method parses percentage values, validates that they are within the 0-100% range, and provides clear error messages for invalid input. The heap size is now calculated based on available system memory when a percentage is used. Test coverage has been added for both valid and invalid cases. Documentation and the JSON schema for CLI options have been updated with examples for both formats. Refs: nodejs#57447

…validation

Asaf-Federman · 2025-07-23T18:22:31Z

I've just force-pushed an update to this branch. I had to amend the commit history to unify the author identity across all commits.

The underlying code logic has not changed.

Apologies for any inconvenience this may cause.

test/parallel/test-max-old-space-size-percentage.js

Asaf-Federman · 2025-07-25T18:01:44Z

The CI failures look unrelated to my changes

nodejs-github-bot · 2025-07-25T20:13:03Z

CI: https://ci.nodejs.org/job/node-test-pull-request/68201/

Asaf-Federman · 2025-07-27T20:15:01Z

It looks like the CI failures are due to unrelated issues, and I'm not sure how to get past them.

Could someone with knowledge of our CI pipeline lend a hand or point me in the right direction? Any help would be greatly appreciated!

Thanks!

nodejs-github-bot · 2025-07-28T00:43:59Z

CI: https://ci.nodejs.org/job/node-test-pull-request/68255/

nodejs-github-bot · 2025-07-28T05:06:18Z

Landed in 0bbe7c3

This commit adds support for specifying --max-old-space-size as a percentage of system memory, in addition to the existing MB format. A new HandleMaxOldSpaceSizePercentage method parses percentage values, validates that they are within the 0-100% range, and provides clear error messages for invalid input. The heap size is now calculated based on available system memory when a percentage is used. Test coverage has been added for both valid and invalid cases. Documentation and the JSON schema for CLI options have been updated with examples for both formats. Refs: nodejs#57447 PR-URL: nodejs#59082 Reviewed-By: Chengzhong Wu <legendecas@gmail.com> Reviewed-By: James M Snell <jasnell@gmail.com> Reviewed-By: Moshe Atlow <moshe@atlow.co.il> Reviewed-By: theanarkh <theratliter@gmail.com> Reviewed-By: Daeyeon Jeong <daeyeon.dev@gmail.com>

This commit adds support for specifying --max-old-space-size as a percentage of system memory, in addition to the existing MB format. A new HandleMaxOldSpaceSizePercentage method parses percentage values, validates that they are within the 0-100% range, and provides clear error messages for invalid input. The heap size is now calculated based on available system memory when a percentage is used. Test coverage has been added for both valid and invalid cases. Documentation and the JSON schema for CLI options have been updated with examples for both formats. Refs: #57447 PR-URL: #59082 Reviewed-By: Chengzhong Wu <legendecas@gmail.com> Reviewed-By: James M Snell <jasnell@gmail.com> Reviewed-By: Moshe Atlow <moshe@atlow.co.il> Reviewed-By: theanarkh <theratliter@gmail.com> Reviewed-By: Daeyeon Jeong <daeyeon.dev@gmail.com>

This MR contains the following updates: | Package | Update | Change | |---|---|---| | [node](https://nodejs.org) ([source](https://github.com/nodejs/node)) | minor | `24.5.0` -> `24.6.0` | MR created with the help of [el-capitano/tools/renovate-bot](https://gitlab.com/el-capitano/tools/renovate-bot). **Proposed changes to behavior should be submitted there as MRs.** --- ### Release Notes <details> <summary>nodejs/node (node)</summary> ### [`v24.6.0`](https://github.com/nodejs/node/releases/tag/v24.6.0): 2025-08-14, Version 24.6.0 (Current), @RafaelGSS [Compare Source](nodejs/node@v24.5.0...v24.6.0) ##### Notable Changes - \[[`471fe712b3`](nodejs/node@471fe712b3)] - **(SEMVER-MINOR)** **cli**: add NODE\_USE\_SYSTEM\_CA=1 (Joyee Cheung) [#59276](nodejs/node#59276) - \[[`38aedfbf73`](nodejs/node@38aedfbf73)] - **(SEMVER-MINOR)** **crypto**: support ML-DSA KeyObject, sign, and verify (Filip Skokan) [#59259](nodejs/node#59259) - \[[`201304537e`](nodejs/node@201304537e)] - **(SEMVER-MINOR)** **zlib**: add dictionary support to zstdCompress and zstdDecompress (lluisemper) [#59240](nodejs/node#59240) - \[[`e79c93a5d0`](nodejs/node@e79c93a5d0)] - **(SEMVER-MINOR)** **http**: add server.keepAliveTimeoutBuffer option (Haram Jeong) [#59243](nodejs/node#59243) - \[[`c144d69efc`](nodejs/node@c144d69efc)] - **lib**: docs deprecate \_http\_\* (Sebastian Beltran) [#59293](nodejs/node#59293) - \[[`aeb4de55a7`](nodejs/node@aeb4de55a7)] - **(SEMVER-MINOR)** **fs**: port SonicBoom module to fs module as Utf8Stream (James M Snell) [#58897](nodejs/node#58897) ##### Commits - \[[`f7484575ff`](nodejs/node@f7484575ff)] - **assert**: change utils to use index instead of for...of (방진혁) [#59278](nodejs/node#59278) - \[[`269cd16185`](nodejs/node@269cd16185)] - **benchmark**: remove deprecated \_extend from benchmark (Rafael Gonzaga) [#59228](nodejs/node#59228) - \[[`848e49c20b`](nodejs/node@848e49c20b)] - **benchmark**: add fs warmup to writefile-promises (Bruno Rodrigues) [#59215](nodejs/node#59215) - \[[`8c609be1b1`](nodejs/node@8c609be1b1)] - **benchmark**: add calibrate-n script (Rafael Gonzaga) [#59186](nodejs/node#59186) - \[[`6a3bf772d8`](nodejs/node@6a3bf772d8)] - **build**: fix node\_use\_sqlite for GN builds (Shelley Vohr) [#59017](nodejs/node#59017) - \[[`471fe712b3`](nodejs/node@471fe712b3)] - **(SEMVER-MINOR)** **cli**: add NODE\_USE\_SYSTEM\_CA=1 (Joyee Cheung) [#59276](nodejs/node#59276) - \[[`38aedfbf73`](nodejs/node@38aedfbf73)] - **(SEMVER-MINOR)** **crypto**: support ML-DSA KeyObject, sign, and verify (Filip Skokan) [#59259](nodejs/node#59259) - \[[`a312e706cf`](nodejs/node@a312e706cf)] - **crypto**: prepare webcrypto key import/export for modern algorithms (Filip Skokan) [#59284](nodejs/node#59284) - \[[`3a7c2c3a47`](nodejs/node@3a7c2c3a47)] - **deps**: update ada to 3.2.7 (Node.js GitHub Bot) [#59336](nodejs/node#59336) - \[[`8d9ceeaf6a`](nodejs/node@8d9ceeaf6a)] - **deps**: update archs files for openssl-3.5.2 (Node.js GitHub Bot) [#59371](nodejs/node#59371) - \[[`33b06df354`](nodejs/node@33b06df354)] - **deps**: upgrade openssl sources to openssl-3.5.2 (Node.js GitHub Bot) [#59371](nodejs/node#59371) - \[[`fa70f1af77`](nodejs/node@fa70f1af77)] - **deps**: support madvise(3C) across ALL illumos revisions (Dan McDonald) [#58237](nodejs/node#58237) - \[[`f834a6be59`](nodejs/node@f834a6be59)] - **deps**: update undici to 7.13.0 (Node.js GitHub Bot) [#59338](nodejs/node#59338) - \[[`db2417487e`](nodejs/node@db2417487e)] - **deps**: update sqlite to 3.50.4 (Node.js GitHub Bot) [#59337](nodejs/node#59337) - \[[`41978adb08`](nodejs/node@41978adb08)] - **deps**: V8: backport [`493cb53`](nodejs/node@493cb53691be) (Chengzhong Wu) [#59238](nodejs/node#59238) - \[[`05667991ca`](nodejs/node@05667991ca)] - **deps**: V8: backport [`1c3e018`](nodejs/node@1c3e018e7d48) (Renegade334) [#58818](nodejs/node#58818) - \[[`fd61588bb4`](nodejs/node@fd61588bb4)] - **doc**: rename x509.extKeyUsage to x509.keyUsage (Filip Skokan) [#59332](nodejs/node#59332) - \[[`a271ae4360`](nodejs/node@a271ae4360)] - **doc**: fix Pbkdf2Params hash attribute heading (Filip Skokan) [#59395](nodejs/node#59395) - \[[`72cfff165b`](nodejs/node@72cfff165b)] - **doc**: fix missing reference links for server.keepAliveTimeoutBuffer (Lee Jiho) [#59356](nodejs/node#59356) - \[[`8341916772`](nodejs/node@8341916772)] - **doc**: fix grammar in global dispatcher usage (Eng Zer Jun) [#59344](nodejs/node#59344) - \[[`e3e489706b`](nodejs/node@e3e489706b)] - **doc**: run license-builder (github-actions\[bot]) [#59343](nodejs/node#59343) - \[[`46527e8cea`](nodejs/node@46527e8cea)] - **doc**: correct orthography `eg.` → `e.g.` (Jacob Smith) [#59329](nodejs/node#59329) - \[[`d140c3713e`](nodejs/node@d140c3713e)] - **doc**: clarify the need of compiler compatible with c++20 (Rafael Gonzaga) [#59297](nodejs/node#59297) - \[[`95e9cabf9d`](nodejs/node@95e9cabf9d)] - **doc**: clarify release candidate stability index (Filip Skokan) [#59295](nodejs/node#59295) - \[[`a056dd36d2`](nodejs/node@a056dd36d2)] - **doc**: add WDYT to glossary (btea) [#59280](nodejs/node#59280) - \[[`1e2c52f5c4`](nodejs/node@1e2c52f5c4)] - **doc**: add manpage entry for --use-system-ca (Joyee Cheung) [#59273](nodejs/node#59273) - \[[`31a46fdeb4`](nodejs/node@31a46fdeb4)] - **doc**: add path.join and path.normalize clarification (Rafael Gonzaga) [#59262](nodejs/node#59262) - \[[`cff3725ff9`](nodejs/node@cff3725ff9)] - **doc**: fix typo in `test/common/README.md` (Yoo) [#59180](nodejs/node#59180) - \[[`31a9283591`](nodejs/node@31a9283591)] - **doc**: add note on process memoryUsage (fengmk2) [#59026](nodejs/node#59026) - \[[`5a98bff6b8`](nodejs/node@5a98bff6b8)] - **doc**: format safely for `doc-kit` (Aviv Keller) [#59229](nodejs/node#59229) - \[[`95b8b7ea5c`](nodejs/node@95b8b7ea5c)] - **domain**: remove deprecated API call (Alex Yang) [#59339](nodejs/node#59339) - \[[`2990f178bd`](nodejs/node@2990f178bd)] - **fs**: fix glob TypeError on restricted dirs (Sylphy-0xd3ac) [#58674](nodejs/node#58674) - \[[`e2fb4caf9c`](nodejs/node@e2fb4caf9c)] - **fs**: correct error message when FileHandle is transferred (Alex Yang) [#59156](nodejs/node#59156) - \[[`aeb4de55a7`](nodejs/node@aeb4de55a7)] - **(SEMVER-MINOR)** **fs**: port SonicBoom module to fs module as Utf8Stream (James M Snell) [#58897](nodejs/node#58897) - \[[`e79c93a5d0`](nodejs/node@e79c93a5d0)] - **(SEMVER-MINOR)** **http**: add server.keepAliveTimeoutBuffer option (Haram Jeong) [#59243](nodejs/node#59243) - \[[`0fb005a53f`](nodejs/node@0fb005a53f)] - **http2**: set Http2Stream#sentHeaders for raw headers (Darshan Sen) [#59244](nodejs/node#59244) - \[[`e055539604`](nodejs/node@e055539604)] - **lib**: add trace-sigint APIs (theanarkh) [#59040](nodejs/node#59040) - \[[`d2183d860a`](nodejs/node@d2183d860a)] - **lib**: optimize writable stream buffer clearing (Yoo) [#59406](nodejs/node#59406) - \[[`47543a7e17`](nodejs/node@47543a7e17)] - **lib**: handle windows reserved device names on UNC (Rafael Gonzaga) [#59286](nodejs/node#59286) - \[[`c6911f0717`](nodejs/node@c6911f0717)] - **lib**: do not modify prototype deprecated asyncResource (RafaelGSS) [#59195](nodejs/node#59195) - \[[`3c88b769bb`](nodejs/node@3c88b769bb)] - **lib**: restructure assert to become a class (Miguel Marcondes Filho) [#58253](nodejs/node#58253) - \[[`e91b54df59`](nodejs/node@e91b54df59)] - **lib**: handle superscript variants on windows device (Rafael Gonzaga) [#59261](nodejs/node#59261) - \[[`4ee467905d`](nodejs/node@4ee467905d)] - **lib**: use validateString (hotpineapple) [#59296](nodejs/node#59296) - \[[`c144d69efc`](nodejs/node@c144d69efc)] - **lib**: docs deprecate \_http\_\* (Sebastian Beltran) [#59293](nodejs/node#59293) - \[[`c89b67e681`](nodejs/node@c89b67e681)] - **lib**: add type names in source mapped stack traces (Chengzhong Wu) [#58976](nodejs/node#58976) - \[[`5b2363be8d`](nodejs/node@5b2363be8d)] - **lib**: prefer AsyncIteratorPrototype primordial (René) [#59097](nodejs/node#59097) - \[[`41b4f4d694`](nodejs/node@41b4f4d694)] - **meta**: clarify pr objection process further (James M Snell) [#59096](nodejs/node#59096) - \[[`0eb5962f1e`](nodejs/node@0eb5962f1e)] - **meta**: add mailmap entry for aditi-1400 (Aditi) [#59316](nodejs/node#59316) - \[[`a2b72c2304`](nodejs/node@a2b72c2304)] - **meta**: add tsc and build team as codeowners building.md (Rafael Gonzaga) [#59298](nodejs/node#59298) - \[[`d69f3ee1e0`](nodejs/node@d69f3ee1e0)] - **meta**: add nodejs/path to path files (Rafael Gonzaga) [#59289](nodejs/node#59289) - \[[`1e37eab865`](nodejs/node@1e37eab865)] - **node-api**: reword "implementation in an alternative VM" as implementable (Chengzhong Wu) [#59036](nodejs/node#59036) - \[[`64add6302a`](nodejs/node@64add6302a)] - **src**: use simdjson to parse SEA configuration (Joyee Cheung) [#59323](nodejs/node#59323) - \[[`e9c6636585`](nodejs/node@e9c6636585)] - **src**: mark realm leaf classes final (Anna Henningsen) [#59355](nodejs/node#59355) - \[[`42ef8147d1`](nodejs/node@42ef8147d1)] - **src**: warn about FastOneByteString invalidation (James M Snell) [#59275](nodejs/node#59275) - \[[`8686b8037a`](nodejs/node@8686b8037a)] - **src**: remove unused DSAKeyExportJob (Filip Skokan) [#59291](nodejs/node#59291) - \[[`1e5f632666`](nodejs/node@1e5f632666)] - **src**: use C++20 `contains()` method (iknoom) [#59304](nodejs/node#59304) - \[[`22d4683cfe`](nodejs/node@22d4683cfe)] - **src**: added CHECK\_NOT\_NULL check for multiple eq\_wrap\_async (F3lixTheCat) [#59267](nodejs/node#59267) - \[[`6a47ff4943`](nodejs/node@6a47ff4943)] - **src**: clear all linked module caches once instantiated (Chengzhong Wu) [#59117](nodejs/node#59117) - \[[`33728cb4ca`](nodejs/node@33728cb4ca)] - **src**: add nullptr checks in `StreamPipe::New` (Burkov Egor) [#57613](nodejs/node#57613) - \[[`4a907bdad1`](nodejs/node@4a907bdad1)] - **src**: add percentage support to --max-old-space-size (Asaf Federman) [#59082](nodejs/node#59082) - \[[`7c189d4f55`](nodejs/node@7c189d4f55)] - **test**: deflake sequential/test-tls-session-timeout (Joyee Cheung) [#59423](nodejs/node#59423) - \[[`fb0a6fb57f`](nodejs/node@fb0a6fb57f)] - **test**: exclude mock from coverage (Shima Ryuhei) [#59348](nodejs/node#59348) - \[[`7e10f95f13`](nodejs/node@7e10f95f13)] - **test**: split test-fs-cp.js (Joyee Cheung) [#59408](nodejs/node#59408) - \[[`41bcf5f659`](nodejs/node@41bcf5f659)] - **test**: update WPT resources,WebCryptoAPI,webstorage (Filip Skokan) [#59311](nodejs/node#59311) - \[[`f9f3dc94cb`](nodejs/node@f9f3dc94cb)] - **test**: add known issue test for fs.cpSync dereference bug (James M Snell) [#58941](nodejs/node#58941) - \[[`244d0c38a8`](nodejs/node@244d0c38a8)] - **test**: deflake stream-readable-to-web test (Ethan Arrowood) [#58948](nodejs/node#58948) - \[[`564e604a1a`](nodejs/node@564e604a1a)] - **test**: make test-inspector-network-resource sequential (Shima Ryuhei) [#59104](nodejs/node#59104) - \[[`7ab13b7477`](nodejs/node@7ab13b7477)] - **test**: don't use expose internals in test-http-outgoing-buffer.js (Meghan Denny) [#59219](nodejs/node#59219) - \[[`319df3859a`](nodejs/node@319df3859a)] - **test,crypto**: skip unsupported ciphers (Shelley Vohr) [#59388](nodejs/node#59388) - \[[`713c70c32a`](nodejs/node@713c70c32a)] - **test\_runner**: remove unused callee convertion (Alex Yang) [#59221](nodejs/node#59221) - \[[`e4ca30e115`](nodejs/node@e4ca30e115)] - **tools**: disable nullability-completeness warnings (Michaël Zasso) [#59392](nodejs/node#59392) - \[[`dab7f6b542`](nodejs/node@dab7f6b542)] - **tools**: check for std::vector\<v8::Local> in lint (Aditi) [#58497](nodejs/node#58497) - \[[`7b94982eb0`](nodejs/node@7b94982eb0)] - **tools**: allow selecting test subsystems with numbers in their names (Darshan Sen) [#59242](nodejs/node#59242) - \[[`16bbcd8881`](nodejs/node@16bbcd8881)] - **typings**: improve internal binding types (Nam Yooseong) [#59351](nodejs/node#59351) - \[[`76bc4d659b`](nodejs/node@76bc4d659b)] - **typings**: improve internal binding types (Michaël Zasso) [#59176](nodejs/node#59176) - \[[`eecd3272a6`](nodejs/node@eecd3272a6)] - **worker**: add name for worker (theanarkh) [#59213](nodejs/node#59213) - \[[`84c3513ce2`](nodejs/node@84c3513ce2)] - **worker**: implements nits in Web Locks code (Antoine du Hamel) [#59270](nodejs/node#59270) - \[[`bd68fbd753`](nodejs/node@bd68fbd753)] - **worker**: add cpuUsage for worker (theanarkh) [#59177](nodejs/node#59177) - \[[`201304537e`](nodejs/node@201304537e)] - **(SEMVER-MINOR)** **zlib**: add dictionary support to zstdCompress and zstdDecompress (lluisemper) [#59240](nodejs/node#59240) </details> --- ### Configuration 📅 **Schedule**: Branch creation - 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This commit adds support for specifying --max-old-space-size as a percentage of system memory, in addition to the existing MB format. A new HandleMaxOldSpaceSizePercentage method parses percentage values, validates that they are within the 0-100% range, and provides clear error messages for invalid input. The heap size is now calculated based on available system memory when a percentage is used. Test coverage has been added for both valid and invalid cases. Documentation and the JSON schema for CLI options have been updated with examples for both formats. Refs: #57447 PR-URL: #59082 Reviewed-By: Chengzhong Wu <legendecas@gmail.com> Reviewed-By: James M Snell <jasnell@gmail.com> Reviewed-By: Moshe Atlow <moshe@atlow.co.il> Reviewed-By: theanarkh <theratliter@gmail.com> Reviewed-By: Daeyeon Jeong <daeyeon.dev@gmail.com>

aduh95 · 2025-08-25T14:03:35Z

This breaks the CI on v22.x-staging, therefor would require a manual backport to be included in v22.x

This commit adds support for specifying --max-old-space-size as a percentage of system memory, in addition to the existing MB format. A new HandleMaxOldSpaceSizePercentage method parses percentage values, validates that they are within the 0-100% range, and provides clear error messages for invalid input. The heap size is now calculated based on available system memory when a percentage is used. Test coverage has been added for both valid and invalid cases. Documentation and the JSON schema for CLI options have been updated with examples for both formats. Refs: nodejs#57447 PR-URL: nodejs#59082 Reviewed-By: Chengzhong Wu <legendecas@gmail.com> Reviewed-By: James M Snell <jasnell@gmail.com> Reviewed-By: Moshe Atlow <moshe@atlow.co.il> Reviewed-By: theanarkh <theratliter@gmail.com> Reviewed-By: Daeyeon Jeong <daeyeon.dev@gmail.com>

Asaf-Federman · 2025-08-26T10:19:17Z

This breaks the CI on v22.x-staging, therefor would require a manual backport to be included in v22.x

Hi @aduh95, can you please point me to the CI failure?
I opened PR to backport this implemention to v22.x

joyeecheung · 2025-08-26T20:01:45Z

The test added in this PR has failed 14 PRs out of the recent 100 CI runs: #59639

This commit adds support for specifying --max-old-space-size as a percentage of system memory, in addition to the existing MB format. A new HandleMaxOldSpaceSizePercentage method parses percentage values, validates that they are within the 0-100% range, and provides clear error messages for invalid input. The heap size is now calculated based on available system memory when a percentage is used. Test coverage has been added for both valid and invalid cases. Documentation and the JSON schema for CLI options have been updated with examples for both formats. Refs: nodejs#57447 PR-URL: nodejs#59082 Reviewed-By: Chengzhong Wu <legendecas@gmail.com> Reviewed-By: James M Snell <jasnell@gmail.com> Reviewed-By: Moshe Atlow <moshe@atlow.co.il> Reviewed-By: theanarkh <theratliter@gmail.com> Reviewed-By: Daeyeon Jeong <daeyeon.dev@gmail.com>

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Asaf-Federman added 8 commits July 23, 2025 21:19

doc: remove unrelated changes

90f8288

src: introduce max-old-space-size-percentage as a new cli flag

84d3433

doc: remove doc related to modified implementation

ebaa850

doc: change max-old-space-size-percentage type to be number

c377756

doc: revert max-old-space-size-percentage type to be a string

a23ece3

doc: fix linting and doc issues

b919043

src: handle UINT64_MAX (according to libuv doc) and remove redundant …

8e5f5ea

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Asaf-Federman force-pushed the feat/max-old-space-size-percentage branch from a121c70 to 8e5f5ea Compare July 23, 2025 18:19

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nodejs-github-bot merged commit 0bbe7c3 into nodejs:main Jul 28, 2025
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github-actions bot mentioned this pull request Aug 11, 2025

2025-08-12, Version 24.6.0 (Current) #59449

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Asaf-Federman deleted the feat/max-old-space-size-percentage branch August 14, 2025 22:55

aduh95 added the backport-requested-v22.x PRs awaiting manual backport to the v22.x-staging branch. label Aug 25, 2025

Asaf-Federman mentioned this pull request Aug 26, 2025

[v22.x backport] src: add percentage support to --max-old-space-size #59631

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joyeecheung mentioned this pull request Aug 26, 2025

parallel/test-max-old-space-size-percentage is flaky on Windows and armv7l #59639

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aduh95 added backport-open-v22.x Indicate that the PR has an open backport and removed backport-requested-v22.x PRs awaiting manual backport to the v22.x-staging branch. labels Aug 26, 2025

richardlau added the semver-minor PRs that contain new features and should be released in the next minor version. label Sep 17, 2025

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src: add percentage support to --max-old-space-size #59082

src: add percentage support to --max-old-space-size #59082

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