Re: [RFC 6/7] mm: extend process_madvise syscall to support vector arrary

On Thu 30-05-19 17:02:14, Minchan Kim wrote:

On Thu, May 30, 2019 at 08:57:55AM +0200, Michal Hocko wrote:

quoted

On Thu 30-05-19 11:17:48, Minchan Kim wrote:

[...]

quoted

quoted

First time, I didn't think about atomicity about address range race
because MADV_COLD/PAGEOUT is not critical for the race.
However you raised the atomicity issue because people would extend
hints to destructive ones easily. I agree with that and that's why
we discussed how to guarantee the race and Daniel comes up with good idea.

Just for the clarification, I didn't really mean atomicity but rather a
_consistency_ (essentially time to check to time to use consistency).

What do you mean by *consistency*? Could you elaborate it more?

That you operate on the object you have got by some means. In other
words that the range you want to call madvise on hasn't been
remapped/replaced by a different mmap operation.

-- 
Michal Hocko
SUSE Labs