Messages in this thread |  | | Subject | Re: [PATCH RFC] mm/madvise: introduce MADV_POPULATE to prefault/prealloc memory | From | David Hildenbrand <> | Date | Mon, 22 Feb 2021 13:52:16 +0100 |
| |
On 22.02.21 13:46, Michal Hocko wrote: > I am slowly catching up with this thread. > > On Fri 19-02-21 09:20:16, David Hildenbrand wrote: > [...] >> So if we have zero, we write zero. We'll COW pages, triggering a write fault >> - and that's the only good thing about it. For example, similar to >> MADV_POPULATE, nothing stops KSM from merging anonymous pages again. So for >> anonymous memory the actual write is not helpful at all. Similarly for >> hugetlbfs, the actual write is not necessary - but there is no other way to >> really achieve the goal. > > I really do not see why you care about KSM so much. Isn't KSM an > explicit opt-in with a fine grained interface to control which memory to > KSM or not?
Yeah, I think it's opt-in via MADV_MERGEABLE. E.g., QEMU defaults to enable KSM unless explicitly disabled by the user.
But I agree, I got distracted by KSM details.
-- Thanks,
David / dhildenb
|  |