Re: [PATCH] random: avoid reading two cache lines on irq randomness

[Sebastian Andrzej Siewior]

On 2022-09-23 20:28:49 [+0200], Jason A. Donenfeld wrote:
> In order to avoid reading and dirtying two cache lines on every IRQ, move
> the work_struct to the bottom of the fast_pool struct. add_interrupt_
> randomness() always touches .pool and .count, which are currently split,
> because .mix pushes everything down. Instead, move .mix to the bottom,
> so that .pool and .count are always in the first cache line, since the
> .mix is only accessed when the pool is full.
> 
> Fixes: 58340f8e952b ("random: defer fast pool mixing to worker")
> Cc: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
> Cc: Sultan Alsawaf <sultan@xxxxxxxxxxxxxxx>
> Signed-off-by: Jason A. Donenfeld <Jason@xxxxxxxxx>

Reviewed-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>

Yup, makes sense.

Sebastian