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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, SeongJae Park Subject: Re: [PATCH v4 4/5] mm: rename zone->lock to zone->_lock Message-ID: References: <0f340324-502b-4719-b3e7-c7ccd4378385@kernel.org> <20260302143743.220eed4feb36d7572fe726cc@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260302143743.220eed4feb36d7572fe726cc@linux-foundation.org> X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: 08D6A20006 X-Stat-Signature: 1n64nxcsjyj5u5o4797oshdj7zjpj878 X-Rspam-User: X-HE-Tag: 1772547961-876470 X-HE-Meta: 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 E2PwfZY0 sh+DW6EWAKu+JM3byrIRHOPsPXgZaCHTIIUD2u1eYiCrKo/I8Sdk2atqPufW2IHx9/93wQnp6G5077INhkVT3Wsq5IZA9F9CyA8b1Q4S/+FYFrEkr5mourJ6ofZAvEReU3NVXY5fsazRcpvMTferlLL/yocPaervucA/LWjZ0nwN8BbTGKonXiv5eud2Fp5WP/4ugC6uNj9YjKP7ZzcsC5x65w2ZxVt72ixnR7RGQQ8QTvZyXWKn9TkBvNbJ/Pf7qzKfOW279kRsiA4KkiDOyFhWzEufykSSMaOwCpu5g0PdB+DsHpEZUkDkIOqLoaJNBZs5JIHDfZeTGWHTvRpktZsICyeOBgS6noKVms6/GAtW5Xh2VcdcnHaEqzNXYDHflatQ06My3r8UnCxzCvIvnLHCE1JfJzfBVANT8pQFBiJUAnZQ= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: 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. ``span_seqlock`` The seqlock to protect ``zone_start_pfn`` and ``spanned_pages``. It is a - seqlock because it has to be read outside of ``zone->lock``, and it is done in + seqlock because it has to be read outside of ``zone_lock``, and it is done in the main allocator path. However, the seqlock is written quite infrequently. Defined only when ``CONFIG_MEMORY_HOTPLUG`` is enabled. diff --git a/Documentation/trace/events-kmem.rst b/Documentation/trace/events-kmem.rst index 68fa75247488..3c20a972de27 100644 --- a/Documentation/trace/events-kmem.rst +++ b/Documentation/trace/events-kmem.rst @@ -57,7 +57,7 @@ the per-CPU allocator (high performance) or the buddy allocator. If pages are allocated directly from the buddy allocator, the mm_page_alloc_zone_locked event is triggered. This event is important as high -amounts of activity imply high activity on the zone->lock. Taking this lock +amounts of activity imply high activity on the zone_lock. Taking this lock impairs performance by disabling interrupts, dirtying cache lines between CPUs and serialising many CPUs. @@ -79,11 +79,11 @@ contention on the lruvec->lru_lock. mm_page_pcpu_drain page=%p pfn=%lu order=%d cpu=%d migratetype=%d In front of the page allocator is a per-cpu page allocator. It exists only -for order-0 pages, reduces contention on the zone->lock and reduces the +for order-0 pages, reduces contention on the zone_lock and reduces the amount of writing on struct page. When a per-CPU list is empty or pages of the wrong type are allocated, -the zone->lock will be taken once and the per-CPU list refilled. The event +the zone_lock will be taken once and the per-CPU list refilled. The event triggered is mm_page_alloc_zone_locked for each page allocated with the event indicating whether it is for a percpu_refill or not. @@ -92,7 +92,7 @@ which triggers a mm_page_pcpu_drain event. The individual nature of the events is so that pages can be tracked between allocation and freeing. A number of drain or refill pages that occur -consecutively imply the zone->lock being taken once. Large amounts of per-CPU +consecutively imply the zone_lock being taken once. Large amounts of per-CPU refills and drains could imply an imbalance between CPUs where too much work is being concentrated in one place. It could also indicate that the per-CPU lists should be a larger size. Finally, large amounts of refills on one CPU -- 2.47.3