On 2/11/20 2:03 PM, Yang Shi wrote:
On Mon, Feb 10, 2020 at 6:18 PM Gavin Shan <gshan@xxxxxxxxxx> wrote:
On 2/11/20 12:31 PM, Roman Gushchin wrote:
On Tue, Feb 11, 2020 at 10:55:53AM +1100, Gavin Shan wrote:
On 2/11/20 3:17 AM, Roman Gushchin wrote:
On Mon, Feb 10, 2020 at 11:14:45PM +1100, Gavin Shan wrote:
.../...
There is something which might be unrelated to discuss here: the pagecache could be backed
by a low-speed (HDD) or high-speed (SSD) media. So the cost to fetch them from disk to memory
isn't equal, meaning we need some kind of bias during reclaiming. It seems something missed
from current implementation.
Yes, the refault cost was not taken into account. I recalled Johannes
posted a patch series to do swap with refault cost weighted in a
couple of years ago, please see: https://lwn.net/Articles/690079/.
Thanks for the link. Yes, Johannes's patchset is comprehensive, even I
didn't look into the details. The concern I had is fixed bias to pagecaches
backed by different storage device, which have different IO speed. It seems
the patchset was disconnected since v1 because I didn't find a v2 from
google.
Thanks,
Gavin
