create_system_filter(9)

🎀 NAME 🎀

Hiii bestie 💖 this is create_system_filter(9) from the Kernel API Manual, and it does exactly one iconic thing: create a filter for an event subsystem. Slay.

✨ SYNOPSIS ✨

       int create_system_filter (struct trace_subsystem_dir *dir , char
       *filter_str , struct event_filter **filterp );

🫶 ARGUMENTS 🫶

• dir — the descriptor for the subsystem directory. It's giving "where the subsystem lives" energy 🗂️
• filter_str — the filter string. The actual filter text, no cap ✨
• filterp — out param for the created filter, and it is always updated on return. Periodt. 💅

💅 DESCRIPTION 💅

Okay so listen 👀 — create_system_filter is identical to create_filter except that it creates a subsystem filter and always remembers filter_str. That's the whole vibe. Lowkey simple, highkey important. 🦋

Bestie heads up: filterp is an out param, and it's always updated on return — not sometimes, not maybe, always. 💖

🌈 SEE ALSO 🌈

• Kernel file ./kernel/trace/trace_events_filter.c — that's the kernel file, iykyk 🧚
• struct prog_entry(9) — related page, go look 👑
• update_preds(9) — related page, bestie 🔥
• filter_parse_regex(9) — related page, literally 🌸
• create_filter(9) — the sibling function this one is identical to (except for the subsystem-filter + always-remembers-filter_str part) 😭

Made with 💖 from the ./kernel/trace source/version corner, dated October 2026, on the create_system_filter(9) page — byeee bestie, go filter something cute 🎀🫶