nfsd_stats_d...em_usage_add(9)

💅 nfsd_stats_drc_mem_usage_add(9) — like, the Kernel API Manual but make it make sense ✨

okay bestie, so this one lives in the Kernel API Manual and it's genuinely such a tiny little function but it's lowkey doing something cute with memory accounting, so let's get into it 🫶

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🌸 NAME 🌸

nfsd_stats_drc_mem_usage_add — adds up the memory that a cache item is eating. that's it, that's the vibe 💖

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✨ SYNOPSIS ✨

void nfsd_stats_drc_mem_usage_add (struct nfsd_net *nn , s64 amount );

no cap, that's the whole signature. void return, so nothing comes back out — she just does her thing and dips 💅

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🎀 ARGUMENTS 🎀

• nn — the target network namespace, like the little world this is all happening inside 🌈
• amount — byte count. literally just how many bytes we're adding to the tally 🍓

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🦋 DESCRIPTION 🦋

so here's the tea: percpu_counter_add_local keeps all the updates chillin' on the per-CPU fast path. very main character, very low-effort, high-reward ✨

and the sole reader — that's percpu_counter_sum_positive — sums up all the per-CPU deltas. so batching locally? it does not lose accuracy. not even a little. fr fr, the numbers stay correct 😌👑

like, the way that local batching stays accurate because the only reader adds the per-CPU deltas back together — it's giving designed-with-intention 💜

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🔥 SEE ALSO 🔥

y'all should also peek at the kernel file ./fs/nfsd/stats.h and these iconics:

• nfsd_stats_rc_hits_inc(9)
• nfsd_stats_rc_misses_inc(9)
• nfsd_stats_rc_nocache_inc(9)
• nfsd_stats_io_read_add(9)
• nfsd_stats_io_write_add(9)
• nfsd_stats_drc_mem_usage_sub(9)

go read them, iykyk 🌸

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and that's the whole page, bestie — this one's stamped from ./fs/nfsd, dated October 2026, and it's been a pleasure doing stats with you 🧚💖 periodt.