netif_txq_maybe_stop(9)

💅 netif_txq_maybe_stop(9) ✨

okay so bestie, welcome to the netif_txq_maybe_stop(9) page — that's the kernel API manual, and this function is literally the "should I stop this Tx queue or not" bouncer. locklessly, no cap.

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🌸 NAME 🌸

netif_txq_maybe_stop — locklessly stop a Tx queue, if needed 🎀

like, only if needed. it does a vibe check first.

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🦋 SYNOPSIS 🦋

netif_txq_maybe_stop (txq , get_desc , stop_thrs , start_thrs );

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✨ ARGUMENTS ✨

• txq — the struct netdev_queue you're stopping/starting. main character energy, honestly.
• get_desc — grabs the current number of free descriptors. ⚠️ but read the requirements below, fr fr, don't skip them!
• stop_thrs — the minimal number of available descriptors for the queue to be left enabled. cross below this and it's giving "stopped".
• start_thrs — the minimal number of descriptors needed to re-enable the queue. it can be equal to stop_thrs, or higher if you wanna avoid that annoying frequent waking situation 🙈

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💖 DESCRIPTION 💖

heads up, and this is the important bit: all arguments may be evaluated multiple times, so beware of side effects!! 😭 not me warning you twice.

get_desc must be a formula or a function call, and it must always return up-to-date information when evaluated! like, always. no stale data, no vibes-based guesswork.

it's expected to be used from ndo_start_xmit — see the comment on top of the file, iykyk. 📌

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🔥 RETURN 🔥

• 0 — the queue was stopped 🛑
• 1 — the queue was left enabled ✅
• -1 — the queue was re-enabled (it raced with waking 👀)

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👑 SEE ALSO 👑

• Kernel file ./include/net/netdev_queues.h
• struct netdev_config(9)
• struct netdev_stat_ops(9)
• struct netdev_queue_mgmt_ops(9)
• Lockless queue stopping / waking helpers.(9)
• __netif_txq_completed_wake(9)

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🌈 go read the actual header file too, bestie, it's lowkey iconic.

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that's the whole page, periodt 💅 — shoutout to ./include/net for hosting this masterpiece, Kernel API Manual on the tin, dated October 2026. mwah 🫶🎀