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| author | Peter Zijlstra <peterz@infradead.org> | 2023-01-12 20:44:04 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2023-01-13 11:48:18 +0100 |
| commit | 0e985e9d22864e29d5d2b3d909ad15134d7f6d46 (patch) | |
| tree | 710fbac5e48688b81dec48394c2007de459252ce /drivers/cpuidle | |
| parent | 26388a7c353f7b1d3fd8a6df6452fa9773193155 (diff) | |
| download | lwn-0e985e9d22864e29d5d2b3d909ad15134d7f6d46.tar.gz lwn-0e985e9d22864e29d5d2b3d909ad15134d7f6d46.zip | |
cpuidle: Add comments about noinstr/__cpuidle usage
Add a few words on noinstr / __cpuidle usage.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20230112195542.397238052@infradead.org
Diffstat (limited to 'drivers/cpuidle')
| -rw-r--r-- | drivers/cpuidle/cpuidle.c | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c index 73f7d8b763c6..500d1720421e 100644 --- a/drivers/cpuidle/cpuidle.c +++ b/drivers/cpuidle/cpuidle.c @@ -252,6 +252,18 @@ noinstr int cpuidle_enter_state(struct cpuidle_device *dev, instrumentation_begin(); } + /* + * NOTE!! + * + * For cpuidle_state::enter() methods that do *NOT* set + * CPUIDLE_FLAG_RCU_IDLE RCU will be disabled here and these functions + * must be marked either noinstr or __cpuidle. + * + * For cpuidle_state::enter() methods that *DO* set + * CPUIDLE_FLAG_RCU_IDLE this isn't required, but they must mark the + * function calling ct_cpuidle_enter() as noinstr/__cpuidle and all + * functions called within the RCU-idle region. + */ entered_state = target_state->enter(dev, drv, index); if (WARN_ONCE(!irqs_disabled(), "%ps leaked IRQ state", target_state->enter)) |