Messages in this thread | | | Date | Wed, 17 Jan 2018 12:23:04 -0600 (CST) | From | Christopher Lameter <> | Subject | Re: [PATCH] mm: numa: Do not trap faults on shared data section pages. |
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On Tue, 16 Jan 2018, Mel Gorman wrote:
> My main source of discomfort is the fact that this is permanent as two > processes perfectly isolated but with a suitably shared COW mapping > will never migrate the data. A potential improvement to get the reported > bandwidth up in the test program would be to skip the rest of the VMA if > page_mapcount != 1 in a COW mapping as it would be reasonable to assume > the remaining pages in the VMA are also affected and the scan is wasteful. > There are counter-examples to this but I suspect that the full VMA being > shared is the common case. Whether you do that or not;
Same concern here. Typically CAP_SYS_NICE will bypass the check that the page is only mapped to a single process and the check looks exactly like the ones for manual migration. Using CAP_SYS_NICE would be surprising here since autonuma is not triggered by the currently running process.
Can we configure this somehow via sysfs?
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