Re: [PATCH -V6 RESEND 1/3] numa balancing: Migrate on fault among multiple bound nodes
From: Mel Gorman <mgorman@suse.de>
Date: 2020-12-03 10:54:13
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linux-mm, lkml
On Thu, Dec 03, 2020 at 11:25:50AM +0100, Peter Zijlstra wrote:
On Wed, Dec 02, 2020 at 11:40:54AM +0000, Mel Gorman wrote:quoted
On Wed, Dec 02, 2020 at 04:42:32PM +0800, Huang Ying wrote:quoted
Now, NUMA balancing can only optimize the page placement among the NUMA nodes if the default memory policy is used. Because the memory policy specified explicitly should take precedence. But this seems too strict in some situations. For example, on a system with 4 NUMA nodes, if the memory of an application is bound to the node 0 and 1, NUMA balancing can potentially migrate the pages between the node 0 and 1 to reduce cross-node accessing without breaking the explicit memory binding policy.Ok, I think this part is ok and while the test case is somewhat superficial, it at least demonstrated that the NUMA balancing overhead did not offset any potential benefit Acked-by: Mel Gorman <mgorman@suse.de>Who do we expect to merge this, me through tip/sched/core or akpm ?
I would expect akpm, it's much more on the mm side because it affects the semantics of memory policies. It should also have more mm-orientated review than just mine because it affects user-visible semantics and the ability to detect whether the feature is available or not needs to be treated with care. -- Mel Gorman SUSE Labs