From: Mel Gorman <mgorman@suse.de>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Huang Ying <ying.huang@intel.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Andrew Morton <akpm@linux-foundation.org>,
Ingo Molnar <mingo@redhat.com>, Rik van Riel <riel@surriel.com>,
Johannes Weiner <hannes@cmpxchg.org>,
"Matthew Wilcox (Oracle)" <willy@infradead.org>,
Dave Hansen <dave.hansen@intel.com>,
Andi Kleen <ak@linux.intel.com>, Michal Hocko <mhocko@suse.com>,
David Rientjes <rientjes@google.com>,
linux-api@vger.kernel.org
Subject: Re: [PATCH -V6 RESEND 1/3] numa balancing: Migrate on fault among multiple bound nodes
Date: Thu, 3 Dec 2020 10:53:13 +0000 [thread overview]
Message-ID: <20201203105313.GF3306@suse.de> (raw)
In-Reply-To: <20201203102550.GK2414@hirez.programming.kicks-ass.net>
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:
> > On Wed, Dec 02, 2020 at 04:42:32PM +0800, Huang Ying wrote:
> > > 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
next prev parent reply other threads:[~2020-12-03 10:53 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-02 8:42 [PATCH -V6 RESEND 0/3] numa balancing: Migrate on fault among multiple bound nodes Huang Ying
2020-12-02 8:42 ` [PATCH -V6 RESEND 1/3] " Huang Ying
2020-12-02 11:40 ` Mel Gorman
2020-12-03 10:25 ` Peter Zijlstra
2020-12-03 10:53 ` Mel Gorman [this message]
2020-12-04 9:19 ` Huang, Ying
2020-12-10 8:21 ` Huang, Ying
2020-12-02 8:42 ` [PATCH -V6 RESEND 2/3] NOT kernel/man-pages: man2/set_mempolicy.2: Add mode flag MPOL_F_NUMA_BALANCING Huang Ying
2020-12-02 11:43 ` Mel Gorman
2020-12-03 1:49 ` Huang, Ying
2020-12-03 9:37 ` Mel Gorman
2020-12-02 12:33 ` Alejandro Colomar (mailing lists; readonly)
2020-12-08 8:13 ` Huang, Ying
2020-12-18 10:21 ` Alejandro Colomar (mailing lists; readonly)
2020-12-21 1:31 ` Huang, Ying
2020-12-02 8:42 ` [PATCH -V6 RESEND 3/3] NOT kernel/numactl: Support to enable Linux kernel NUMA balancing Huang Ying
2020-12-02 11:45 ` Mel Gorman
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