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Date: Mon, 19 Feb 2024 10:06:10 -0500
From: Phil Auld <pauld@redhat.com>
To: Byungchul Park <byungchul@sk.com>
Cc: mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com,
	vincent.guittot@linaro.org, dietmar.eggemann@arm.com,
	rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de,
	bristot@redhat.com, vschneid@redhat.com,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	kernel_team@skhynix.com, akpm@linux-foundation.org
Subject: Re: [PATCH v4] sched/numa, mm: do not try to migrate memory to
 memoryless nodes
Message-ID: <20240219150610.GB184804@lorien.usersys.redhat.com>
References: <20240219041920.1183-1-byungchul@sk.com>
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In-Reply-To: <20240219041920.1183-1-byungchul@sk.com>

On Mon, Feb 19, 2024 at 01:19:20PM +0900 Byungchul Park wrote:
> Changes from v3:
> 	1. Rewrite the comment in code and the commit message to make it
> 	   more clear. (feedbacked by Oscar Salvador)
> 	2. Add "Reviewed-by: Oscar Salvador <osalvador@suse.de>"
> 
> Changes from v2:
> 	1. Rewrite the comment in code and the commit message becasue it
> 	   turns out that this patch is not the real fix for the oops
> 	   descriped. The real fix goes in another patch below:
> 
> 	   https://lore.kernel.org/lkml/20240216111502.79759-1-byungchul@sk.com/
> 
> Changes from v1:
> 	1. Trim the verbose oops in the commit message. (feedbacked by
> 	   Phil Auld)
> 	2. Rewrite a comment in code. (feedbacked by Phil Auld)
> 
> --->8---
> From 98f5d472c08e3ed5b9b6543290d392a2e50fcf3c Mon Sep 17 00:00:00 2001
> From: Byungchul Park <byungchul@sk.com>
> Date: Mon, 19 Feb 2024 13:10:47 +0900
> Subject: [PATCH v4] sched/numa, mm: do not try to migrate memory to memoryless nodes
> 
> Memoryless nodes do not have any memory to migrate to, so stop trying
> it.
> 
> Signed-off-by: Byungchul Park <byungchul@sk.com>
> Reviewed-by: Oscar Salvador <osalvador@suse.de>
> ---
>  kernel/sched/fair.c | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> index d7a3c63a2171..3e3b44ae72d1 100644
> --- a/kernel/sched/fair.c
> +++ b/kernel/sched/fair.c
> @@ -1828,6 +1828,12 @@ bool should_numa_migrate_memory(struct task_struct *p, struct folio *folio,
>  	int dst_nid = cpu_to_node(dst_cpu);
>  	int last_cpupid, this_cpupid;
>  
> +	/*
> +	 * Cannot migrate to memoryless nodes.
> +	 */
> +	if (!node_state(dst_nid, N_MEMORY))
> +		return false;
> +
>  	/*
>  	 * The pages in slow memory node should be migrated according
>  	 * to hot/cold instead of private/shared.
> -- 
> 2.17.1
> 
> 

Sorry, hadn't gotten far enough to see this version when I replied to v3...

Reviewed-by: Phil Auld <pauld@redhat.com>


Cheers,
Phil

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