Re: [PATCH] Revert "MIPS: csrc-r4k: Select HAVE_UNSTABLE_SCHED_CLOCK if SMP && 64BIT"

[Jiaxun Yang]

在2024年12月23日十二月 上午9:20，Xi Ruoyao写道：
> This reverts commit 426fa8e4fe7bb914b5977cbce453a9926bf5b2e6.
>
> The commit has caused two issues on Loongson 3A4000:
>
> 1. The timestamp in dmesg become erratic, like:
>
>     [3.736957] amdgpu 0000:04:00.0: ... ...
>     [3.748895] [drm] Initialized amdgpu ... ...
>     [18446744073.381141] amdgpu 0000:04:00:0: ... ...
>     [1.613326] igb 0000:03:00.0 enp3s0: ... ...
>
> 2. More seriously, some workloads (for example, the test
>    stdlib/test-cxa_atexit2 in the Glibc test suite) triggers an RCU
>    stall and hang the system with a high probably (4 hangs out of 5
>    tests).
>
> Revert this commit to use jiffie on Loongson MIPS systems and fix these
> issues for now.  The root cause may need more investigation.
>
> Cc: stable@xxxxxxxxxxxxxxx # 6.11+
> Cc: Jiaxun Yang <jiaxun.yang@xxxxxxxxxxx>
> Cc: Icenowy Zheng <icenowy@xxxxxxx>

Reviewed-by: Jiaxun Yang <jiaxun.yang@xxxxxxxxxxx>

It's indeed problematic in some scenarios.

Let's revert for now.

Thanks
- Jiaxun

> Signed-off-by: Xi Ruoyao <xry111@xxxxxxxxxxx>
> ---
>  arch/mips/Kconfig | 1 -
>  1 file changed, 1 deletion(-)
>
> diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
> index 467b10f4361a..5078ebf071ec 100644
> --- a/arch/mips/Kconfig
> +++ b/arch/mips/Kconfig
> @@ -1084,7 +1084,6 @@ config CSRC_IOASIC
> 
>  config CSRC_R4K
>  	select CLOCKSOURCE_WATCHDOG if CPU_FREQ
> -	select HAVE_UNSTABLE_SCHED_CLOCK if SMP && 64BIT
>  	bool
> 
>  config CSRC_SB1250
> -- 
> 2.47.1

-- 
- Jiaxun