On 10/24/2012 02:16 PM, Ni zhan Chen wrote:
On 10/24/2012 08:02 PM, Izik Eidus wrote:
On 10/24/2012 01:59 PM, Ni zhan Chen wrote:
On 10/24/2012 07:46 PM, Izik Eidus wrote:
On 10/24/2012 01:19 PM, Ni zhan Chen wrote:
Hi all,
I have some questions about ksm.
1) khugepaged default nice value is 19, but ksmd default nice
value is 5, why this big different?
2) why ksm doesn't support pagecache and tmpfs now? What's the
bottleneck?
3) ksm kernel doc said that "KSM only merges anonymous(private)
pages, never pagecache(file) pages". But where judege it should be
private?
4) ksm kernel doc said that "To avoid the instability and the
resulting false negatives to be permanent, KSM re-initializes the
unstable tree root node to an empty tree, at every KSM pass." But
I can't find where re-initializes the unstable tree, could you
explain me?
in scan_get_next_rmap_item(), if (slot == &ksm_mm_head) then we do
root_unstable_tree = RB_ROOT; this will result in
root_unstable_tree being empty.
thanks Izik, what about the other three questions?
Question number 2 is beacuse it is forced to work with anonymous
pages, about question 3 - I will have to remember why from the very
begining I wrote it to support only anonymous pages (few years have
been passed), maybe Andrea/Huge have it more hot in their heads?
The initialize goal of design ksm is for virtualization, but now it
also can be used for other apps. So can it also support tmpfs or
pagecache in the future?
Talking from far memory, I remember it was easier/cleaner to only
support anonymous pages, until Andrea/Huge won`t remind us why I can`t
answer this
(Maybe later I will have some time to read a little bit the code again
and to remember what is going on in linux VM...)
Thanks in advance. :-)
Regards,
Chen
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