Re: [RFC PATCH] hwpoison, memory_hotplug: allow hwpoisoned pages to be offlined

[osalvador]

> > This commit adds shake_page() for mlocked pages to make sure that the 
> > target
> > page is flushed out from LRU cache. Without this shake_page(), 
> > subsequent
> > delete_from_lru_cache() (from me_pagecache_clean()) fails to isolate 
> > it and
> > the page will finally return back to LRU list.  So this scenario leads 
> > to
> > "hwpoisoned by still linked to LRU list" page.
>
> OK, I see. So does that mean that the LRU handling is no longer needed
> and there is a guanratee that all kernels with the above commit cannot
> ever get an LRU page?

For the sake of completeness:

I made a quick test reverting 286c469a988 on upstream kernel.
As expected, the poisoned page is in LRU when it hits do_migrate_range,
and so, the migration path is taken and I see the exact failure I saw 
on. 4.4


Oscar Salvador
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Suse L3