update_cond_flag(9)

✨ NAME ✨

okay so picture this: we're deep in the Kernel API Manual, section 9, and today's main character is update_cond_flag 💅 her whole job? Set or reset the TRIGGER_COND bit. that's it, that's the tweet 🐦

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🌸 SYNOPSIS 🌸

void update_cond_flag (struct trace_event_file *file );

literally one parameter, no drama, we love a low-maintenance function 🫶

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🎀 ARGUMENTS 🎀

• file — the trace_event_file that's associated with the event. that's your girl, that's the one you're passing in 💖

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🦋 DESCRIPTION 🦋

okay bestie, listen, this is the whole vibe check right here 👑

So if an event has triggers, and any of those triggers has a filter or a post_trigger, then trigger invocation needs to be deferred until after the current event has logged its data. and when that's the case, the event should have its TRIGGER_COND bit set 🔥

Otherwise? the TRIGGER_COND bit should be cleared. no bit, no deferred invocation, no problem 🧹

fr fr the entire logic is just "does this event have a filtered or post trigger → set the bit, else clear it." iconic, honestly. not me being obsessed with a conditional 💀

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🌈 SEE ALSO 🌈

if you wanna go down the rabbit hole (and you do, iykyk), start with the kernel file:

• ./kernel/trace/trace_events_trigger.c

and then the whole friend group 🫶:

• event_triggers_call(9)
• event_triggers_post_call(9)
• event_trigger_count(9)
• event_trigger_print(9)
• event_trigger_init(9)
• event_trigger_free(9)
• clear_event_triggers(9)
• register_trigger(9)
• unregister_trigger(9)
• event_trigger_check_remove(9)
• event_trigger_empty_param(9)
• event_trigger_separate_filter(9)
• trigger_data_alloc(9)
• event_trigger_parse_num(9)
• event_trigger_set_filter(9)
• event_trigger_reset_filter(9)
• event_trigger_register(9)
• event_trigger_unregister(9)
• event_trigger_parse(9)
• set_trigger_filter(9)
• find_named_trigger(9)
• is_named_trigger(9)
• save_named_trigger(9)
• del_named_trigger(9)
• pause_named_trigger(9)
• unpause_named_trigger(9)
• set_named_trigger_data(9)

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🌸 okay that's the page!! this lil cutie lives in ./kernel/trace, she's dated October 2026, and she goes by update_cond_flag(9) — go forth and set some bits bestie, ily, bye 🎀💜✨