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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 Message-ID: References: <20260304151335.172572-1-sj@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: 725171A0016 X-Stat-Signature: cegxnezkjmetea8btg53hmu34bxqhn37 X-Rspam-User: X-HE-Tag: 1772734588-988957 X-HE-Meta: U2FsdGVkX1/ycdenISwCSaDmKzgFQKPqj1BGNZwPg/DizDRqHmSTqG6KIzTrryFbS4Df3ZFrz5dVRP4tdB5r2VDPugvlTeJoUUX9AVs8MXtO5L+Ubne7SVsaq7PF2uOr7EcNJXRcbliW6iwkGbAe3z4dhG/udHH+vg5bBqCCMvYfcu6wNKYh87vn4d2gpOGS8UVOJalfp/piDhn6jjDqMGUslN4sjhTfFqCqxbVo4WXBmzblAI95HmUJ1n/B/1gWS/BrEW+/1LWk+G3TCR7VU732JTEDwCgQlb9R6D3JBExmBEe0v6SWVlCNNZqHUUan/s8uSsvnJDhxNE+9UOJpRY6mHHBvj89DNiMf3+I+Enj9BsOGDTobqIgG7B9hBlyI6+Og48rcK5SAElkT+kXVBCV2MH5lMJFGWhBbndKjH0EmhKJNg0BGsU9bYYP/3fPc4J7B6OmJtp0fyNbV1qWx8Zb4ainbFU25xPXZVNAx1SC1MmDEyFxyTPbyZdLwlt094FbmLGrgDTKgbEj76ksF/dw1CZe8H4tTAcXq2CfGocssJ4ExjcBucOz23IshTySFiQsemgDVmdi/A1iXob1STdI6DDnsWOraK62YwTkuhwq7vP4Pc6YENMfvAG3pwv9+1Nmc9NCj2PwNqcvNVeS6NPaho4/jSfxFg8T13ie3dzQax75k10jH/hEAw23m2ht+LbbSGwJslMp7oCKXVOzYjfPeQbIKfGGcHjSMhw8pux+dI/ymrlwZK+9/2Px6JDeCj5kgCYm2yAaAJm4994EcITBvTgYvPPFxoohAKgqjyFSRVYmB7rrXqTQKd0dl6vMfUXjMtoP2KTsb8YhXqWCWUfNnJ+dr0sA7X/bcfQJ5HoQX/lUTvhf3HaK/lZNEtjD0njEi7KogaLXmVtHhxNPz4LXnFS1YbPIPWpPINGI/7QbzU0zCuycnI2lg2t26p1psyX8RVwLHiMkDkTl0BA9 iwQlMFyk NgeC8oCMw79wXQ8cVj/e2/QEv+4OhCCpkRwIENLhdN3s/r53Wjeug2dXvxLzsqCfkttqzFu0IDneCtkARgtYO0s/7hwvec2t32Bo+qokb6drWRt/f83x4lt3u8ku4a04MRxhaAoSKZnCwJDG+ZkevgGTTBA1xiJdiULVgnmeqzCYedpMK7kUzVs4LBsZT5a8oCgVoOuEbaw5IEozyHGwrWbeYUQd8euQmX4ApalyOVRoHx3GnCL04gR5mxa16H5L6AErUZna3M2vTLe8qH+NGyhIutDrtD1DRfnw/9rzg2q99S/uQKhCiG1k3jlcUuxPY5ukKbJnlJiwoj1EdwkfGIOQvol1q4T4FJ7X6nWvucjeyH5jsfHVr3qbghklHo27yTUixhBN2ob8h6HwP3RmpkXADuWZKnsFVS/FtIBUsYOdivD8= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Thu, Mar 05, 2026 at 10:27:07AM +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. Thanks for the suggestion, Vlastimil. That sounds reasonable to me as well. I'll update the comments and documentation to consistently use "zone lock".