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 E21803064A9; Thu, 5 Mar 2026 09:27:14 +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=1772702835; cv=none; b=hYQ5F6q0n94QBNDACVM/r6qTdQsuRIZoxLk/VsDMsdkzvdkKwdOEIYlIztpr0zQzAzg1B2pdPkAAtw9YepcFW6PJ1l25jXFnQMBvlYX6+xtr0fDZKYeHLRXpsBWRNOBdc7QGLrImW9AocTVUI4bszFln1S7Du+FnkgZ8Qc6pU8g= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772702835; c=relaxed/simple; bh=2PM4TCzaL7PIpbUAvBpvBfsaqfpwHgfynLyCMx106LY=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=lIVtQjnhXwA2OJapxhpd4C+wuSsWf/mLUnrL1Q1doEOpSEehyeLunBxRgYaqHRp/FwPqtP2ihlvmT5p5aMAFwRQoY0BP4CEKn/Teml3V+oKmsxEhMXCgloppBjwbWs3ETeT+rswecQNY4EXsnEXkjHe6dqSwgbyJYzhYnjynAKQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=SY8eFLte; 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="SY8eFLte" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 255C4C2BCAF; Thu, 5 Mar 2026 09:27:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1772702834; bh=2PM4TCzaL7PIpbUAvBpvBfsaqfpwHgfynLyCMx106LY=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=SY8eFLtecDllvoK9zUMo9qn2jHOAd5sY4zp6ILJ66Tr4bib3tFLTEtqxACNUgf2y2 sCF0z+E/B7kUMZf4O3fGNtuQ/24k78Eut7nDBiyY/DUio7LYHlDa4fJCI8+vngGo4t mcpN54APp4sE8UiwGy14kbUMLM9AYwa2N1MZY34ywwEZ2GTqrHnMyi+2TyTqr76X43 siVYvzHvBqHZK3sjeZJr1IT43mBMhO04EGXLkzT0d7BcsKWku/qd++43Awvfl2u0U+ +Q/jopx6C5PRPyDyZFEW27mfdvkbjRLyk1NnDVtAm295ARYETRb7NTRJhd893NOMHz qeuaSyL+N5G5w== Message-ID: Date: Thu, 5 Mar 2026 10:27:07 +0100 Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v4 4/5] mm: rename zone->lock to zone->_lock Content-Language: en-US To: SeongJae Park , Dmitry Ilvokhin Cc: 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 References: <20260304151335.172572-1-sj@kernel.org> From: "Vlastimil Babka (SUSE)" In-Reply-To: <20260304151335.172572-1-sj@kernel.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit 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.