From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4CCE119E7F7; Thu, 5 Mar 2026 14:55:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772722558; cv=none; b=sUvPizFcIq80xvDC+EjCJC4jYuWRH7Ygfu+IQrFt+dNL7/BHYh+8AAyP2aL7fS5tzKpxatLvv9AWT5jWdvKdyxHiT9HwNvG+YN13gkHoeF1hZjjwAc6viwtkLOjcdLQNf6E4NBYSbwFd4sgsl2V/KUB5CQNhEE5Z5gon4i0iEpM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772722558; c=relaxed/simple; bh=amy+SaJwg+WdNFtVzm4GtX3Td8Gs26jX8LxmkTno6mc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=U3Mk4iSn2LUjVZKAAMxooUYrbdTcEfUElNMHX6cOyDidJ49CalfNIZTsuDMCPzHsM5mm/yGU409GyANWuM7HETxbi0ZpHq1ddSlbeA5rCedHZI+U+zdhXf/vaCdoI1j7KKaja6amq/JjrCyRg81TeTlNb658nEI8ZceXecQuE4I= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Kn5ytd+7; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Kn5ytd+7" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 29C8BC116C6; Thu, 5 Mar 2026 14:55:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1772722557; bh=amy+SaJwg+WdNFtVzm4GtX3Td8Gs26jX8LxmkTno6mc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Kn5ytd+7nTBuHR5VYD0Y5pcHIekfqTi0HrmCH4uShdxcHMRM7QLt0UwhiTR0IAXYz 8hyJKh3UnfDvpbf53kXXwIhziqGlXZfM6ZO4elMz/qwqRp8PvKa34BhMm3nGfQfsjy 6mJb2bH+1wsynJJnIzCil2M1AxaznsFfQhSK4gzHpjTaB3mlb6qPmBxW/MqVTIvTw8 xZp6Dq7zDPTxggBKUBqxELmoACZFjNpGe8DSbeET7G2D7F02Tvj+o7EWMf6DB8q4yX VIe5zQXI5oniyBBqu7mjnlt+h7uCI2+LLBUN8vpMlXFRZP3RRkekTtfllNd9L3uaBA Xm2NkkFxJkvsA== From: SeongJae Park To: "Vlastimil Babka (SUSE)" Cc: SeongJae Park , Dmitry Ilvokhin , Andrew Morton , David Hildenbrand , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Axel Rasmussen , Yuanchu Xie , Wei Xu , Steven Rostedt , Masami Hiramatsu , Mathieu Desnoyers , "Rafael J. Wysocki" , Pavel Machek , Len Brown , Brendan Jackman , Johannes Weiner , Zi Yan , Oscar Salvador , Qi Zheng , Shakeel Butt , linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-trace-kernel@vger.kernel.org, linux-pm@vger.kernel.org Subject: Re: [PATCH v4 4/5] mm: rename zone->lock to zone->_lock Date: Thu, 5 Mar 2026 06:55:54 -0800 Message-ID: <20260305145555.86081-1-sj@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-pm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit On Thu, 5 Mar 2026 10:27:07 +0100 "Vlastimil Babka (SUSE)" wrote: > On 3/4/26 16:13, SeongJae Park wrote: > > On Wed, 4 Mar 2026 13:01:45 +0000 Dmitry Ilvokhin wrote: > > > >> On Tue, Mar 03, 2026 at 05:50:34PM -0800, SeongJae Park wrote: > >> > On Tue, 3 Mar 2026 14:25:55 +0000 Dmitry Ilvokhin wrote: > >> > > >> > > On Mon, Mar 02, 2026 at 02:37:43PM -0800, Andrew Morton wrote: > >> > > > On Mon, 2 Mar 2026 15:10:03 +0100 "Vlastimil Babka (SUSE)" wrote: > >> > > > > >> > > > > On 2/27/26 17:00, Dmitry Ilvokhin wrote: > >> > > > > > This intentionally breaks direct users of zone->lock at compile time so > >> > > > > > all call sites are converted to the zone lock wrappers. Without the > >> > > > > > rename, present and future out-of-tree code could continue using > >> > > > > > spin_lock(&zone->lock) and bypass the wrappers and tracing > >> > > > > > infrastructure. > >> > > > > > > >> > > > > > No functional change intended. > >> > > > > > > >> > > > > > Suggested-by: Andrew Morton > >> > > > > > Signed-off-by: Dmitry Ilvokhin > >> > > > > > Acked-by: Shakeel Butt > >> > > > > > Acked-by: SeongJae Park > >> > > > > > >> > > > > I see some more instances of 'zone->lock' in comments in > >> > > > > include/linux/mmzone.h and under Documentation/ but otherwise LGTM. > >> > > > > > >> > > > > >> > > > I fixed (most of) that in the previous version but my fix was lost. > >> > > > >> > > Thanks for the fixups, Andrew. > >> > > > >> > > I still see a few 'zone->lock' references in Documentation remain on > >> > > mm-new. This patch cleans them up, as noted by Vlastimil. > >> > > > >> > > I'm happy to adjust this patch if anything else needs attention. > >> > > > >> > > From 9142d5a8b60038fa424a6033253960682e5a51f4 Mon Sep 17 00:00:00 2001 > >> > > From: Dmitry Ilvokhin > >> > > Date: Tue, 3 Mar 2026 06:13:13 -0800 > >> > > Subject: [PATCH] mm: fix remaining zone->lock references > >> > > > >> > > Signed-off-by: Dmitry Ilvokhin > >> > > --- > >> > > Documentation/mm/physical_memory.rst | 4 ++-- > >> > > Documentation/trace/events-kmem.rst | 8 ++++---- > >> > > 2 files changed, 6 insertions(+), 6 deletions(-) > >> > > > >> > > diff --git a/Documentation/mm/physical_memory.rst b/Documentation/mm/physical_memory.rst > >> > > index b76183545e5b..e344f93515b6 100644 > >> > > --- a/Documentation/mm/physical_memory.rst > >> > > +++ b/Documentation/mm/physical_memory.rst > >> > > @@ -500,11 +500,11 @@ General > >> > > ``nr_isolate_pageblock`` > >> > > Number of isolated pageblocks. It is used to solve incorrect freepage counting > >> > > problem due to racy retrieving migratetype of pageblock. Protected by > >> > > - ``zone->lock``. Defined only when ``CONFIG_MEMORY_ISOLATION`` is enabled. > >> > > + ``zone_lock``. Defined only when ``CONFIG_MEMORY_ISOLATION`` is enabled. > >> > > >> > Dmitry's original patch [1] was doing 's/zone->lock/zone->_lock/', which aligns > >> > to my expectation. But this patch is doing 's/zone->lock/zone_lock/'. Same > >> > for the rest of this patch. > >> > > >> > I was initially thinking this is just a mistake, but I also found Andrew is > >> > doing same change [2], so I'm bit confused. Is this an intentional change? > >> > > >> > [1] https://lore.kernel.org/d61500c5784c64e971f4d328c57639303c475f81.1772206930.git.d@ilvokhin.com > >> > [2] https://lore.kernel.org/20260302143743.220eed4feb36d7572fe726cc@linux-foundation.org > >> > > >> > >> Good catch, thanks for pointing this out, SJ. > >> > >> Originally the mechanical rename was indeed zone->lock -> zone->_lock. > >> However, in Documentation I intentionally switched references to > >> zone_lock instead of zone->_lock. The reasoning is that _lock is now an > >> internal implementation detail, and direct access is discouraged. The > >> intended interface is via the zone_lock_*() / zone_unlock_*() wrappers, > >> so referencing zone_lock in documentation felt more appropriate than > >> mentioning the private struct field (zone->_lock). > > > > Thank you for this nice and kind clarification, Dmitry! I agree mentioning > > zone_[un]lock_*() helpers instead of the hidden member (zone->_lock) can be > > better. > > > > But, I'm concerned if people like me might not aware the intention under > > 'zone_lock'. If there is a well-known convention that allows people to know it > > is for 'zone_[un]lock_*()' helpers, making it more clear would be nice, in my > > humble opinion. If there is such a convention but I'm just missing it, please > > ignore. If I'm not, for eaxmaple, > > > > "protected by ``zone->lock``" could be re-wrote to > > "protected by ``zone_[un]lock_*()`` locking helpers" or, > > "protected by zone lock helper functions (``zone_[un]lock_*()``)" ? > > > >> > >> That said, I agree this creates inconsistency with the mechanical > >> rename, and I'm happy to adjust either way: either consistently refer > >> to the wrapper API, or keep documentation aligned with zone->_lock. > >> > >> I slightly prefer referring to the wrapper API, but don't have a strong > >> preference as long as we're consistent. > > > > I also think both approaches are good. But for the wrapper approach, I think > > giving more contexts rather than just ``zone_lock`` to readers would be nice. > > Grep tells me that we also have comments mentioning simply "zone lock", btw. > And it's also a term used often in informal conversations. Maybe we could > just standardize on that in comments/documentations as it's easier to read. > Discovering that the field is called _lock and that wrappers should be used, > is hopefully not that difficult. Sounds good, that also works for me. Thanks, SJ