#memory management

At the 2026 Linux Storage, Filesystem, Memory Management, and BPF Summit, a session led by Miklos Szeredi discussed problems caused by excessive negative dentries in directories, including soft lockups, reference count overflow, and long hash chains. Negative dentries are a key optimization for filesystem lookups, but when a directory accumulates millions of them, they can cause severe performance issues and even security side-channel problems. The proposals discussed could lead to kernel patches that improve filesystem reliability and memory management. Proposed solutions include moving negative dentries to the end of the dchildren list so iterators can stop early, adding condresched() calls to avoid soft lockups, or switching to a more suitable data structure. Concerns were raised about ordering issues with getdents() and potential complications when a negative dentry becomes positive.

Two large memory-management patch sets, developed with LLM assistance by established kernel developers, are being reviewed by the Linux kernel community. This marks a shift in how AI-generated contributions are received, as patches from respected developers are taken seriously, potentially setting a precedent for future LLM-assisted work. One patch set by Rik van Riel introduces 'super page blocks' to reliably allocate 1GB huge pages without the inflexible hugetlbfs reservation system, addressing memory fragmentation challenges.