Re: [PATCH v4 4/5] mm: rename zone->lock to zone->_lock

[Andrew Morton]

On Mon, 2 Mar 2026 15:10:03 +0100 "Vlastimil Babka (SUSE)" <vbabka@xxxxxxxxxx> 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 <akpm@xxxxxxxxxxxxxxxxxxxx>
> > Signed-off-by: Dmitry Ilvokhin <d@xxxxxxxxxxxx>
> > Acked-by: Shakeel Butt <shakeel.butt@xxxxxxxxx>
> > Acked-by: SeongJae Park <sj@xxxxxxxxxx>
> 
> 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.


 include/linux/mmzone.h |   10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

--- a/include/linux/mmzone.h~mm-rename-zone-lock-to-zone-_lock-fix
+++ a/include/linux/mmzone.h
@@ -1037,12 +1037,12 @@ struct zone {
 	 * Locking rules:
 	 *
 	 * zone_start_pfn and spanned_pages are protected by span_seqlock.
-	 * It is a seqlock because it has to be read outside of zone->lock,
+	 * It is a seqlock because it has to be read outside of zone_lock,
 	 * and it is done in the main allocator path.  But, it is written
 	 * quite infrequently.
 	 *
-	 * The span_seq lock is declared along with zone->lock because it is
-	 * frequently read in proximity to zone->lock.  It's good to
+	 * The span_seq lock is declared along with zone_lock because it is
+	 * frequently read in proximity to zone_lock.  It's good to
 	 * give them a chance of being in the same cacheline.
 	 *
 	 * Write access to present_pages at runtime should be protected by
@@ -1065,7 +1065,7 @@ struct zone {
 	/*
 	 * Number of isolated pageblock. It is used to solve incorrect
 	 * freepage counting problem due to racy retrieving migratetype
-	 * of pageblock. Protected by zone->lock.
+	 * of pageblock. Protected by zone_lock.
 	 */
 	unsigned long		nr_isolate_pageblock;
 #endif
@@ -1502,7 +1502,7 @@ typedef struct pglist_data {
 	 * manipulate node_size_lock without checking for CONFIG_MEMORY_HOTPLUG
 	 * or CONFIG_DEFERRED_STRUCT_PAGE_INIT.
 	 *
-	 * Nests above zone->lock and zone->span_seqlock
+	 * Nests above zone_lock and zone->span_seqlock
 	 */
 	spinlock_t node_size_lock;
 #endif
_