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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-Archived-By: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261028134647.3176080-1-zhanxusheng1024@gmail.com> X-Rspamd-Queue-Id: 0A5D440003 X-Rspam-User: X-Stat-Signature: ntfkg714nmsa986so36pzpx8pawxd318 X-Spam-Status: No, score=-15.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_PASS, SPF_PASS autolearn=ham autolearn_force=no version=4.0.1 X-Rspamd-Server: rspam03 X-HE-Tag: 1793201034-340339 X-HE-Meta: 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 eQ1O0eHb 4ejKjV6FcN8bLxLD6uaBX87w/ldXl5KQMfFYuPfmzVdupFYMM/SFfQhyO1hKhHIGmIdGQ6FTt3Y3HyssumWulAvKv/8JJ6pSosXkK8jPF12CV9b0EtGuBIZ2JGkjS3I9MxbM5tHLstsfoaN/V3HdVaA5gErSQ7OohyzwcZDppdljMUzHPYIB5FnD9Z2Q0wiDXiwmG7MyfVaD0f6H5koqNKsKjriugnP9vJju3axsMOT1gfdEPqWBfIijXfwzkaMZ3Am1HvyCXKE+hNzy/mfZMGzXviubJlutyfNV0bTLiGp5BttIfjP/kfkFVijecuSEERdyaUgtHeWpk2tJTfbQlFr1H8A== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 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