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5f7fa17ad8
- Expose the ioprio enabled flag as an atomic for relaxed inline checks - Inline SetFrom construction so disabled read/write paths avoid a function call - Move priority application into a slow helper used only when ioprio is enabled
61 lines
1.5 KiB
C++
61 lines
1.5 KiB
C++
/*
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ISC License
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Copyright (c) 2026, Antonio SJ Musumeci <trapexit@spawn.link>
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Permission to use, copy, modify, and/or distribute this software for any
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purpose with or without fee is hereby granted, provided that the above
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copyright notice and this permission notice appear in all copies.
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THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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#pragma once
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#include <atomic>
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#include <sys/types.h>
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namespace ioprio
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{
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// Exposed so the disabled-path check in SetFrom can inline into
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// every fuse_read/fuse_write as an atomic load + branch, with no
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// function overhead.
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extern std::atomic<bool> _enabled;
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[[gnu::always_inline]]
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inline
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bool
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enabled()
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{
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return _enabled.load(std::memory_order_relaxed);
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}
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void enable(const bool);
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int get(const int who);
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int set(const int who, const int ioprio);
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struct SetFrom
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{
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static thread_local int thread_prio;
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[[gnu::always_inline]]
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inline
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SetFrom(const pid_t pid_)
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{
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if(ioprio::enabled())
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_slow_apply(pid_);
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}
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private:
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void _slow_apply(const pid_t);
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};
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};
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