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From: "Vlastimil Babka (SUSE)" <vbabka@kernel.org>
To: Hao Li <hao.li@linux.dev>, harry@kernel.org
Cc: akpm@linux-foundation.org, cl@gentwo.org, rientjes@google.com,
	roman.gushchin@linux.dev, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3] mm/slub: deduplicate NUMA policy calculation in allocation paths
Date: Fri, 26 Jun 2026 13:08:25 +0200	[thread overview]
Message-ID: <bc85aefa-ad3b-412c-a931-a0b94e77a8fa@kernel.org> (raw)
In-Reply-To: <20260624100320.430115-1-hao.li@linux.dev>

On 6/24/26 12:00, Hao Li wrote:
> Currently, alloc_from_pcs() and __slab_alloc_node() both calculate the
> NUMA policy independently. Since they are called consecutively in paths
> like __kmalloc_nolock_noprof() and slab_alloc_node(), this leads to
> redundant code snippets.
> 
> Introduce a helper function to resolve the NUMA policy once, eliminating
> the duplicated code and reducing execution overhead.
> 
> Also remove __slab_alloc_node() function because it is almost empty.
> The callers of __slab_alloc_node now call ___slab_alloc() directly.
> 
> Additional notes:
> 
>   Previously, when slab_strict_numa was enabled, alloc_from_pcs() and
>   __slab_alloc_node() could each resolve the task mempolicy, so
>   MPOL_INTERLEAVE or MPOL_WEIGHTED_INTERLEAVE could advance the
>   interleave state twice for a single object allocation attempt.
>   And each retry will also advance the interleave state.
> 
>   With this change, the strict NUMA node is resolved once and reused by
>   both alloc_from_pcs() and ___slab_alloc() in each retry.
> 
>   This is a behavior change, but it better matches the intent of
>   selecting one policy node for one allocation attempt.
> 
> Signed-off-by: Hao Li <hao.li@linux.dev>

Cool!
Added to slab/for-7.3/misc, will exponse to -next after 7.2-rc1.



      parent reply	other threads:[~2026-06-26 11:08 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-06-24 10:00 [PATCH v3] mm/slub: deduplicate NUMA policy calculation in allocation paths Hao Li
2026-06-25  4:35 ` Harry Yoo
2026-06-26 11:08 ` Vlastimil Babka (SUSE) [this message]

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