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

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

[Xi Ruoyao]

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@vger.kernel.org # 6.11+
Cc: Jiaxun Yang <jiaxun.yang@flygoat.com>
Cc: Icenowy Zheng <icenowy@aosc.io>
Signed-off-by: Xi Ruoyao <xry111@xry111.site>
---
 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

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@vger.kernel.org # 6.11+
> Cc: Jiaxun Yang <jiaxun.yang@flygoat.com>
> Cc: Icenowy Zheng <icenowy@aosc.io>

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

It's indeed problematic in some scenarios.

Let's revert for now.

Thanks
- Jiaxun

> Signed-off-by: Xi Ruoyao <xry111@xry111.site>
> ---
>  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

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

[Thomas Bogendoerfer]

On Mon, Dec 23, 2024 at 05:20:41PM +0800, Xi Ruoyao wrote:
> 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@vger.kernel.org # 6.11+
> Cc: Jiaxun Yang <jiaxun.yang@flygoat.com>
> Cc: Icenowy Zheng <icenowy@aosc.io>
> Signed-off-by: Xi Ruoyao <xry111@xry111.site>
> ---
>  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

applied to mips-next.

Thomas.

-- 
Crap can work. Given enough thrust pigs will fly, but it's not necessarily a
good idea.                                                [ RFC1925, 2.3 ]