Re: [LTP] [PATCH] Set tunable value of min_free_kbytes lower

[Zhouping Liu <zliu@redhat.com>]

----- Original Message -----
> From: "shuang qiu" <shuang.qiu@oracle.com>
> To: ltp-list@lists.sourceforge.net
> Sent: Thursday, August 23, 2012 2:43:01 PM
> Subject: [LTP] [PATCH] Set tunable value of min_free_kbytes lower
> 
> From: Shuang Qiu <shuang.qiu@oracle.com>
> 
> The value of min_free_kbytes is set too high(half of mem_free) during
> testing min_free_kbytes tunable.It often cause the system to become
> out-of-memory.Using 20% of mem_free to avoid oom and system hang.

Hi, shuang

I met the issue that min_free_kbytes caused system hang before, and what you said made sense.

but after tested the patch, I found it still make the system hang with the patch, so I don't think
this patch can fix the issue completely, maybe there are other factors, or need lower tune value.
always suppose it was because of the high tune value, it's more better to add an optional to control it.
also I will investigate it deeper to look after the real reason. please comment if you have other ideas.

Thanks,
Zhouping

> ---
>  testcases/kernel/mem/tunable/min_free_kbytes.c |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
> 
> diff --git a/testcases/kernel/mem/tunable/min_free_kbytes.c
> b/testcases/kernel/mem/tunable/min_free_kbytes.c
> index 00ead04..8a03f85 100644
> --- a/testcases/kernel/mem/tunable/min_free_kbytes.c
> +++ b/testcases/kernel/mem/tunable/min_free_kbytes.c
> @@ -128,7 +128,7 @@ static void test_tune(unsigned long
> overcommit_policy)
>  		/* case2 */
>  		else {
>  			memfree = read_meminfo("MemFree:");
> -			tune = memfree / 2;
> +			tune = memfree / 5;
>  			set_sys_tune("min_free_kbytes", tune, 1);
>  		}
>  
> --
> 1.7.7
> 
> 
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