linux-kernel - Re: [RFC PATCH 01/15] static kmem

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Message-ID: <20260114073840.GT3634291@ZenIV>
Date: Wed, 14 Jan 2026 07:38:40 +0000
From: Al Viro <viro@...iv.linux.org.uk>
To: Harry Yoo <harry.yoo@...cle.com>
Cc: linux-mm@...ck.org, Vlastimil Babka <vbabka@...e.cz>,
	linux-fsdevel@...r.kernel.org,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Christian Brauner <brauner@...nel.org>, Jan Kara <jack@...e.cz>,
	Mateusz Guzik <mguzik@...il.com>, linux-kernel@...r.kernel.org
Subject: Re: [RFC PATCH 01/15] static kmem_cache instances for core caches

On Wed, Jan 14, 2026 at 04:30:24PM +0900, Harry Yoo wrote:

> SLAB_NO_MERGE prevents both side of merging - when 1) creating the cache,
> and when 2) another cache tries to create an alias from it.
> 
> Avoiding 1) makes sense, but is there a reason to prevent 2)?
> 
> If it's fine for other caches to merge into a cache with static
> duration, then it's sufficient to update find_mergeable() to not attempt
> creating an alias during cache creation if args->preallocated is
> specified (instead of using SLAB_NO_MERGE).

Umm...  For static-in-module - definitely (what if it goes away before
the dynamic alias?), for globally static... might be fine, I guess...