Re: tmem frontswap without swap file

[Bob Liu <bob.liu@oracle.com>]

On 02/24/2014 07:01 PM, Vasiliy Tolstov wrote:
> 2014-02-24 7:32 GMT+04:00 Bob Liu <bob.liu@oracle.com>:
>> Two types of page can be stored in tmem: persistent_page and ephemeral_page.
>>
>> Persistent pages are swapped-out pages, whose date can't be dropped by
>> tmem. The rule for persistent pages is:
>> 'current_domain_pages +  persistent_pages have to smaller than
>> domain->max_pages'.
>>
>> Ephemeral pages are clean pagecache pages, those pages have a copy in
>> disk already.
>> The amount number of ephemeral pages are not limited, but XEN host will
>> reclaim those pages if under memory pressure.
>> There is a tmem parameter 'weight' which can be used to control how many
>> ephemeral_pages should be reclaimed between domains.
> 
> 
> Very good, thanks for answers! What minimal kernel versions recommends
> for frontswap/cleancache in domU (dom0 xen 4.3.2)
> 

Any version started from v3.5 should be okay, I'd recommend versions
after v3.10 since there were hardly no commits since that version.

And I suggest you apply this patch also(which haven't been merged to
linus' git tree yet)
https://git.kernel.org/cgit/linux/kernel/git/konrad/xen.git/commit/?h=stable/for-linus-3.14&id=bc1b0df59e3fc4573f92bc1aab9652047a0aeaa7

-- 
Regards,
-Bob