On Tue 22-09-20 16:06:31, Yafang Shao wrote:

On Tue, Sep 22, 2020 at 3:27 PM Michal Hocko [off-list ref] wrote:

[...]

quoted

What is the latency triggered by the memory reclaim? It should be mostly
a clean page cache right as drop_caches only drops clean pages. Or is
this more about [id]cache? Do you have any profiles where is the time
spent?

Yes, we have analyzed the issues in the direct reclaim, but that is
not the point.

Are those fixed?

The point is that each case may take us several days to analyze, while
the user can't wait, so they will use drop_caches to workaround it
until we find the solution.

As I've said there are several options to achieve an immediate action.
Careful resource domains configuration will certainly help with that.
-- 
Michal Hocko
SUSE Labs