Re: [PATCH] x86/intel_rdt: use __this_cpu_read in pseudo_lock_fn()

[Reinette Chatre]

Hi,

On 7/22/2021 7:33 PM, Hui Su wrote:
> The code is executed with interrupts disabled,
> so it's safe to use __this_cpu_read().

True ... but could you please elaborate what the issue is with using 
this_cpu_read()? It too is safe to use when interrupts are disabled.

> Signed-off-by: Hui Su <suhui@xxxxxxxx>
> ---
>   arch/x86/kernel/cpu/resctrl/pseudo_lock.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/kernel/cpu/resctrl/pseudo_lock.c b/arch/x86/kernel/cpu/resctrl/pseudo_lock.c
> index 2207916cae65..f0cc0a89333b 100644
> --- a/arch/x86/kernel/cpu/resctrl/pseudo_lock.c
> +++ b/arch/x86/kernel/cpu/resctrl/pseudo_lock.c
> @@ -464,8 +464,8 @@ static int pseudo_lock_fn(void *_rdtgrp)
>   	 * cache.
>   	 */
>   	__wrmsr(MSR_MISC_FEATURE_CONTROL, prefetch_disable_bits, 0x0);
> -	closid_p = this_cpu_read(pqr_state.cur_closid);
> -	rmid_p = this_cpu_read(pqr_state.cur_rmid);
> +	closid_p = __this_cpu_read(pqr_state.cur_closid);
> +	rmid_p = __this_cpu_read(pqr_state.cur_rmid);
>   	mem_r = plr->kmem;
>   	size = plr->size;
>   	line_size = plr->line_size;

Reinette