kernel_oct targets a WROOM-2 N32R8V: octal flash, and 8 MB of PSRAM for the page pool. The defaults size the pool for that part, with 8 pages of 64 KiB for each of the text, data and heap regions, so 1.5 MB per process. fork() duplicates the address environment, so a parent and a child need 3 MB at once and a module with 2 MB of PSRAM cannot do it. kernel_n8r2 sizes the same build for such a module. Each region is 2 pages, so a process takes 384 KiB and a fork() peaks at 768 KiB, inside a 1.5 MB pool placed at 0x80000 to leave the start of the PSRAM alone. The flash is quad and runs in DIO mode, so this configuration also exercises the CONFIG_ESP32S3_FLASH_MODE_OCT guard in kernel-space.ld from the quad side, which kernel_oct cannot. This is tight by construction. ostest has 115 KiB of text against a 128 KiB text region. A larger program needs a module with more PSRAM, not a larger pool. Verified on an ESP32-S3-DevKitC with an N8R2 module, 8 MB flash in DIO mode and 2 MB of embedded quad PSRAM. ostest reports "Parent and child had independent memory" and exits with status 0. Assisted-by: Claude Opus 5 (1M context) <noreply@anthropic.com> Signed-off-by: Marco Casaroli <marco.casaroli@gmail.com> |
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| arch | ||
| audio | ||
| binfmt | ||
| boards | ||
| cmake | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| dummy | ||
| fs | ||
| graphics | ||
| include | ||
| libs | ||
| mm | ||
| net | ||
| openamp | ||
| pass1 | ||
| sched | ||
| syscall | ||
| tools | ||
| video | ||
| wireless | ||
| .asf.yaml | ||
| .codespell-ignore-lines | ||
| .codespellrc | ||
| .editorconfig | ||
| .gitignore | ||
| .gitmessage | ||
| .pre-commit-config.yaml | ||
| .yamllint | ||
| AUTHORS | ||
| CMakeLists.txt | ||
| CONTRIBUTING.md | ||
| INVIOLABLES.md | ||
| Kconfig | ||
| LICENSE | ||
| Makefile | ||
| NOTICE | ||
| README.md | ||
| ReleaseNotes | ||
Apache NuttX is a real-time operating system (RTOS) with an emphasis on standards compliance and small footprint. Scalable from 8-bit to 64-bit microcontroller environments, the primary governing standards in NuttX are POSIX and ANSI standards. Additional standard APIs from Unix and other common RTOSs (such as VxWorks) are adopted for functionality not available under these standards, or for functionality that is not appropriate for deeply-embedded environments (such as fork()).
For brevity, many parts of the documentation will refer to Apache NuttX as simply NuttX.
Getting Started
First time on NuttX? Read the Getting Started guide! If you don't have a board available, NuttX has its own simulator that you can run on terminal.
Documentation
You can find the current NuttX documentation on the Documentation Page.
Alternatively, you can build the documentation yourself by following the Documentation Build Instructions.
The old NuttX documentation is still available in the Apache wiki.
Supported Boards
NuttX supports a wide variety of platforms. See the full list on the Supported Platforms page.
Contributing
If you wish to contribute to the NuttX project, read the Contributing guidelines for information on Git usage, coding standard, workflow and the NuttX principles.
License
The code in this repository is under either the Apache 2 license, or a license compatible with the Apache 2 license. See the License Page for more information.