From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793201035; b=OuMLf2QdMu9wiwUOn9qmm+nImIzRYeRBVGSBumdHSqJrVrBYwr6GGm7fvca0fEf2luHD CBhpNbFvdvckDxwofzLVBlHvSYdmduwf0W1LK9mPkVoou13de+xnNOnPCYXhBvTvsvz3b jl1qG8KkLMi5+jCsuW3uHB0jngWYz8mHjUY8tMSXbg73Jnr85plAR8A3CksBUNZDwtvje XrrWijPuz+KJT/i2AbPop3ZP1FZA170dqVGlEprdOv8xqSSNJIYP0N+nVHfyI0oJmJfSD qUDSbRdESepkDEJl8gGDXlC70GrbAQkzMIanBls5j+94xOHbZM001nj1GTnsvZkUJTw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793201035; h=Received:DKIM-Signature:Date:From:To:Cc:Subject:Message-ID: References:MIME-Version:Content-Type:Content-Disposition:In-Reply-To; bh=QoAi1anA30nDGqKRjbCzfsCZ7EvAt6aSj8TnMwEh3bM=; b=fuxHUXWV5s8MorMPcHfxg9N4gIMacLFmpXTpPvP0ZiVzauSHOg9yjuZEPyo1eQ9g5NvS Da3y+rUNBZ5q1uAMbl7sj3o5id4bb0cZgqc3yhjpkEdhpenYWM6l5G8yHVZIFijEL8cyE xiOpK1AUp98nMc9uBdONwL3sa588PG+8cs1WsgRedWUskriaYgW/7QssPkzIPWIQ7fA7R +6LVG8Z/KIe+xvCUl2ztvzgkRiPpPWovwJSUblOCeeZVFB1zC21nGHrB2UUoWLX2Ip/mQ EFeHZqTm9uFX6NueTkQOLKyYC7G/zFi26SmIeFq/Cty92G4J+vQvqS1bn/XT8ovu2GQ== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b="QogTgp/f"; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A8D4E606AB31; Wed, 28 Oct 2026 15:23:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=QogTgp/f Received: by smtp.kernel.org (Postfix) with ESMTPSA id BC1811F031E2; Wed, 28 Oct 2026 15:23:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793201034; bh=QoAi1anA30nDGqKRjbCzfsCZ7EvAt6aSj8TnMwEh3bM=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=QogTgp/fyqrvv5e9CqlhTtGIq+W8x6/uxNE2xmzsUGwM/UVDak56B0zQhzPTw/XIx 2vW39ozxc2ZgxP3Xo/kYwlWCg95EeMGtonvOtzWrQ2DQMsRq1Wbd8osUOqjAjodSSk bBv5sIEW+uMTV7S2TnA49X+RBu+dCjJAd8MuIdsk39QNfZU6PKF9zcUMqky3UxfM9a tJtnlXxiNNLZI5LO0QR8saDVGrIcbvm2EPXkdTqPU525Z6mKKUPnZzmeZz1NwAmejb 51VSD7zVbK4RDOWqC+ermR6/GuWVtwEHvLSfYDS4oDkpMwvM4M0F8or7hIZE6ORgCY UpIpC2upTbHwg== Date: Wed, 28 Oct 2026 15:23:52 +0000 From: Harry Yoo To: Zhan Xusheng Cc: vbabka@kernel.org, urezki@gmail.com, paulmck@kernel.org, qiang.zhang@linux.dev, akpm@linux-foundation.org, hao.li@linux.dev, cl@gentwo.org, rientjes@google.com, roman.gushchin@linux.dev, linux-mm@kvack.org, rcu@vger.kernel.org, linux-kernel@vger.kernel.org, zhanxusheng@xiaomi.com Subject: Re: [PATCH 1/2] mm/slab: restore the rcutree. prefix of the kvfree_rcu parameters Message-ID: References: <20261028134647.3176080-1-zhanxusheng1024@gmail.com> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261028134647.3176080-1-zhanxusheng1024@gmail.com> On Wed, Oct 28, 2026 at 09:46:46PM +0800, Zhan Xusheng wrote: > From: Zhan Xusheng > > The move of kvfree_rcu() to mm/slab_common.c dropped the "rcutree." > MODULE_PARAM_PREFIX, so rcu_min_cached_objs and > rcu_delay_page_cache_fill_msec became slab_common.* and the documented > rcutree.* names are silently ignored. Restore the prefix; the > slab_common.* names, never documented, stop working. > > Fixes: bbe658d65802 ("mm/slab: Move kvfree_rcu() into SLAB") We should add: Cc: stable@vger.kernel.org This is a functional regression and in MM we don't automatically backport fixes to -stable unless without this tag. > Signed-off-by: Zhan Xusheng > --- > mm/slab_common.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/mm/slab_common.c b/mm/slab_common.c > index 01c64ef661e7..3729aa7a6156 100644 > --- a/mm/slab_common.c > +++ b/mm/slab_common.c > @@ -1373,6 +1373,10 @@ void __init kvfree_rcu_init(void) > * per-CPU. Object size is equal to one page. This value > * can be changed at boot time. > */ > +/* These used to be rcutree parameters; keep their documented names. */ > +#undef MODULE_PARAM_PREFIX > +#define MODULE_PARAM_PREFIX "rcutree." This should be moved to before "This rcu parameter is runtime-read-only ..." part? And perhaps let's rephrase the comment, something like: /* Keep the prefix inherited from RCU */ With that adjusted, otherwise looks good to me, so: Reviewed-by: Harry Yoo (Meta) -- Cheers, Harry / Hyeonggon