set_compression_callback(9)

💅 set_compression_callback — the Kernel API Manual, bestie edition ✨

okay so real talk, you're reading the set_compression_callback(9) page from the kernel API manual and honestly? it's a whole vibe. it's giving "tiny function, huge friend group" because this thing lives in ./drivers/md/dm-vdo and it's surrounded by like sixty other functions at all times. main character energy fr fr 💖

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🌸 NAME 🌸

set_compression_callback — literally the callback that turns compression on or off. that's it. that's the whole job. no cap 🎀

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✨ SYNOPSIS ✨

void set_compression_callback (struct vdo_completion *completion );

like yes bestie, that's the entire signature, and yes the space before the closing paren is just how it's written, we don't fix it, we respect it 🫶

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🦋 ARGUMENTS 🦋

• completion — the completion. (i know, i know, deeply unhelpful one-liner, but that's what the page says, so that's what we're saying. it's a struct vdo_completion * and it's the completion. periodt.) 💅

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🔥 SEE ALSO 🔥

bestie. sit down. hydrate. this is the friend group and it is long. every single one of these is a (9) page, and they all hang out together in the vdo corner of the kernel:

• Introduction(9)
• vdo_initialize_device_registry_once(9)
• filter_vdos_locked(9)
• vdo_find_matching(9)
• initialize_thread_config(9)
• get_thread_name(9)
• vdo_make_thread(9)
• register_vdo(9)
• vdo_format(9)
• initialize_vdo(9)
• vdo_make(9)
• free_listeners(9)
• unregister_vdo(9)
• vdo_destroy(9)
• finish_reading_super_block(9)
• handle_super_block_read_error(9)
• vdo_load_super_block(9)
• vdo_get_backing_device(9)
• vdo_get_device_name(9)
• vdo_synchronous_flush(9)
• vdo_get_state(9)
• vdo_set_state(9)
• vdo_get_admin_state(9)
• record_vdo(9)
• continue_parent(9)
• handle_geometry_block_save_error(9)
• vdo_save_geometry_block(9)
• handle_super_block_save_error(9)
• vdo_save_super_block(9)
• vdo_save_components(9)
• vdo_register_read_only_listener(9)
• notify_vdo_of_read_only_mode(9)
• vdo_enable_read_only_entry(9)
• vdo_wait_until_not_entering_read_only_mode(9)
• as_notifier(9)
• finish_entering_read_only_mode(9)
• make_thread_read_only(9)
• vdo_allow_read_only_mode_entry(9)
• vdo_enter_read_only_mode(9)
• vdo_is_read_only(9)
• vdo_in_read_only_mode(9)
• vdo_in_recovery_mode(9)
• vdo_enter_recovery_mode(9)
• complete_synchronous_action(9)
• perform_synchronous_action(9)
• vdo_set_compressing(9)
• vdo_get_compressing(9)
• vdo_get_physical_blocks_allocated(9)
• vdo_get_physical_blocks_overhead(9)
• get_vdo_statistics(9)
• vdo_fetch_statistics_callback(9)
• vdo_fetch_statistics(9)
• vdo_get_callback_thread_id(9)
• vdo_dump_status(9)
• vdo_assert_on_admin_thread(9)
• vdo_assert_on_logical_zone_thread(9)
• vdo_assert_on_physical_zone_thread(9)
• vdo_get_physical_zone(9)

ngl, if you actually read all of those in one sitting you deserve a little treat. 🍓 like genuinely, go get one.

the file these all live near is ./drivers/md/dm-vdo/vdo.c, so if you're doing a deep dive, start at Introduction(9) and vibe your way down. iykyk 🌈

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🧚 sign-off 🧚

that's the whole page, bestie — short, sweet, and absolutely carried by its friend list. it ships from ./drivers/md/dm-vdo and it's dated October 2026, so mark your calendar and stan responsibly. ⭐

set_compression_callback(9) — you ate, honestly. 👑💜