Re: [RFC][PATCH 0/4] memcg: add support for hwpoison testing

[Balbir Singh <balbir@linux.vnet.ibm.com>]

* Wu Fengguang <fengguang.wu@intel.com> [2009-08-31 18:26:40]:

> Hi all,
> 
> In hardware poison testing, we want to inject hwpoison errors to pages
> of a collection of selected tasks, so that random tasks (eg. init) won't
> be killed in stress tests and lead to test failure.
> 
> Memory cgroup provides an ideal tool for tracking and testing these target
> process pages. All we have to do is to
> - export the memory cgroup id via cgroupfs
> - export two functions/structs for hwpoison_inject.c
> 
> This might be an unexpected usage of memory cgroup. The last patch and this
> script demonstrates how the exported interfaces are to be used to limit the
> scope of hwpoison injection.
> 
> 	test -d /cgroup/hwpoison && rmdir /cgroup/hwpoison
> 	mkdir /cgroup/hwpoison
> 
> 	usemem -m 100 -s 100 &   # eat 100MB and sleep 100s
> 	echo `pidof usemem` > /cgroup/hwpoison/tasks
> 
> ==>     memcg_id=$(</cgroup/hwpoison/memory.id)
> ==>     echo $memcg_id > /debug/hwpoison/corrupt-filter-memcg
> 
> 	# hwpoison all pfn
> 	pfn=0
> 	while true
> 	do      
> 		let pfn=pfn+1
> 		echo $pfn > /debug/hwpoison/corrupt-pfn
> 		if [ $? -ne 0 ]; then
> 			break
> 		fi
> 	done
> 
> Comments are welcome, thanks!
>

I took a quick look and the patches seem OKAY to me, but I have
question, can't we do all of this from user space? The bits about
id export and import the ids look like they can be replaced by names
in user space.
 
> Cheers,
> Fengguang
> -- 
> 

-- 
	Balbir

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