On Fri, Feb 20, 2026 at 01:10:05PM -0600, Cheatham, Benjamin wrote:
> On 2/11/2026 9:22 AM, Dmitry Ilvokhin wrote:
> > Compaction uses compact_lock_irqsave(), which currently operates
> > on a raw spinlock_t pointer so that it can be used for both
> > zone->lock and lru_lock. Since zone lock operations are now wrapped,
> > compact_lock_irqsave() can no longer operate directly on a spinlock_t
> > when the lock belongs to a zone.
> >
> > Introduce struct compact_lock to abstract the underlying lock type. The
> > structure carries a lock type enum and a union holding either a zone
> > pointer or a raw spinlock_t pointer, and dispatches to the appropriate
> > lock/unlock helper.
> >
> > No functional change intended.
> >
> > Signed-off-by: Dmitry Ilvokhin <[email protected]>
> > ---
> > mm/compaction.c | 108 +++++++++++++++++++++++++++++++++++++++---------
> > 1 file changed, 89 insertions(+), 19 deletions(-)
> >
> > diff --git a/mm/compaction.c b/mm/compaction.c
> > index 1e8f8eca318c..1b000d2b95b2 100644
> > --- a/mm/compaction.c
> > +++ b/mm/compaction.c
> > @@ -24,6 +24,7 @@
> > #include <linux/page_owner.h>
> > #include <linux/psi.h>
> > #include <linux/cpuset.h>
> > +#include <linux/zone_lock.h>
> > #include "internal.h"
> >
> > #ifdef CONFIG_COMPACTION
> > @@ -493,6 +494,65 @@ static bool test_and_set_skip(struct compact_control
> > *cc, struct page *page)
> > }
> > #endif /* CONFIG_COMPACTION */
> >
> > +enum compact_lock_type {
> > + COMPACT_LOCK_ZONE,
> > + COMPACT_LOCK_RAW_SPINLOCK,
> > +};
> > +
> > +struct compact_lock {
> > + enum compact_lock_type type;
> > + union {
> > + struct zone *zone;
> > + spinlock_t *lock; /* Reference to lru lock */
> > + };
> > +};
> > +
> > +static bool compact_do_zone_trylock_irqsave(struct zone *zone,
> > + unsigned long *flags)
> > +{
> > + return zone_trylock_irqsave(zone, *flags);
> > +}
> > +
> > +static bool compact_do_raw_trylock_irqsave(spinlock_t *lock,
> > + unsigned long *flags)
> > +{
> > + return spin_trylock_irqsave(lock, *flags);
> > +}
> > +
> > +static bool compact_do_trylock_irqsave(struct compact_lock lock,
> > + unsigned long *flags)
> > +{
> > + if (lock.type == COMPACT_LOCK_ZONE)
> > + return compact_do_zone_trylock_irqsave(lock.zone, flags);
> > +
> > + return compact_do_raw_trylock_irqsave(lock.lock, flags);
> > +}
>
> Nit: You could remove the helpers above and just do the calls directly in
> this function, though
> it would remove the parity with the compact helpers.
> compact_do_lock_irqsave() helpers can stay
> since they have the __acquires() annotations.
Yes, I agree, there is no much value in this wrappers, will remove them,
thanks!
> > +
> > +static void compact_do_zone_lock_irqsave(struct zone *zone,
> > + unsigned long *flags)
> > +__acquires(zone->lock)
> > +{
> > + zone_lock_irqsave(zone, *flags);
> > +}
> > +
> > +static void compact_do_raw_lock_irqsave(spinlock_t *lock,
> > + unsigned long *flags)
> > +__acquires(lock)
> > +{
> > + spin_lock_irqsave(lock, *flags);
> > +}
> > +
> > +static void compact_do_lock_irqsave(struct compact_lock lock,
> > + unsigned long *flags)
> > +{
> > + if (lock.type == COMPACT_LOCK_ZONE) {
> > + compact_do_zone_lock_irqsave(lock.zone, flags);
> > + return;
> > + }
> > +
> > + return compact_do_raw_lock_irqsave(lock.lock, flags);
>
> You don't need the return statement here (and you shouldn't be returning a
> value at all).
Yes, agree, will fix in v2.
>
> It may be cleaner to just do an if-else statement here instead.
>
> > +}
> > +
> > /*
> > * Compaction requires the taking of some coarse locks that are potentially
> > * very heavily contended. For async compaction, trylock and record if the
> > @@ -502,19 +562,19 @@ static bool test_and_set_skip(struct compact_control
> > *cc, struct page *page)
> > *
> > * Always returns true which makes it easier to track lock state in
> > callers.
> > */
> > -static bool compact_lock_irqsave(spinlock_t *lock, unsigned long *flags,
> > - struct compact_control *cc)
> > - __acquires(lock)
> > +static bool compact_lock_irqsave(struct compact_lock lock,
> > + unsigned long *flags,
> > + struct compact_control *cc)
> > {
> > /* Track if the lock is contended in async mode */
> > if (cc->mode == MIGRATE_ASYNC && !cc->contended) {
> > - if (spin_trylock_irqsave(lock, *flags))
> > + if (compact_do_trylock_irqsave(lock, flags))
> > return true;
> >
> > cc->contended = true;
> > }
> >
> > - spin_lock_irqsave(lock, *flags);
> > + compact_do_lock_irqsave(lock, flags);
> > return true;
> > }
> >
> > @@ -530,11 +590,13 @@ static bool compact_lock_irqsave(spinlock_t *lock,
> > unsigned long *flags,
> > * Returns true if compaction should abort due to fatal signal pending.
> > * Returns false when compaction can continue.
> > */
> > -static bool compact_unlock_should_abort(spinlock_t *lock,
> > - unsigned long flags, bool *locked, struct compact_control *cc)
> > +static bool compact_unlock_should_abort(struct zone *zone,
> > + unsigned long flags,
> > + bool *locked,
> > + struct compact_control *cc)
> > {
> > if (*locked) {
> > - spin_unlock_irqrestore(lock, flags);
> > + zone_unlock_irqrestore(zone, flags);
>
> I would move this (and other wrapper changes below that don't use compact_*)
> to the last patch. I understand you
> didn't change it due to location but I would argue it isn't really relevant
> to what's being added in this patch
> and fits better in the last.
Thanks for the suggestion. Totally makes sense to me, will do in v2 as well.
>
> > *locked = false;
> > }
> >
> > @@ -582,9 +644,8 @@ static unsigned long isolate_freepages_block(struct
> > compact_control *cc,
> > * contention, to give chance to IRQs. Abort if fatal signal
> > * pending.
> > */
> > - if (!(blockpfn % COMPACT_CLUSTER_MAX)
> > - && compact_unlock_should_abort(&cc->zone->lock, flags,
> > - &locked, cc))
> > + if (!(blockpfn % COMPACT_CLUSTER_MAX) &&
> > + compact_unlock_should_abort(cc->zone, flags, &locked, cc))
> > break;
> >
> > nr_scanned++;
> > @@ -613,8 +674,12 @@ static unsigned long isolate_freepages_block(struct
> > compact_control *cc,
> >
> > /* If we already hold the lock, we can skip some rechecking. */
> > if (!locked) {
> > - locked = compact_lock_irqsave(&cc->zone->lock,
> > - &flags, cc);
> > + struct compact_lock zol = {
> > + .type = COMPACT_LOCK_ZONE,
> > + .zone = cc->zone,
> > + };
> > +
> > + locked = compact_lock_irqsave(zol, &flags, cc);
> >
> > /* Recheck this is a buddy page under lock */
> > if (!PageBuddy(page))
> > @@ -649,7 +714,7 @@ static unsigned long isolate_freepages_block(struct
> > compact_control *cc,
> > }
> >
> > if (locked)
> > - spin_unlock_irqrestore(&cc->zone->lock, flags);
> > + zone_unlock_irqrestore(cc->zone, flags);
> >
> > /*
> > * Be careful to not go outside of the pageblock.
> > @@ -1157,10 +1222,15 @@ isolate_migratepages_block(struct compact_control
> > *cc, unsigned long low_pfn,
> >
> > /* If we already hold the lock, we can skip some rechecking */
> > if (lruvec != locked) {
> > + struct compact_lock zol = {
> > + .type = COMPACT_LOCK_RAW_SPINLOCK,
> > + .lock = &lruvec->lru_lock,
> > + };
> > +
> > if (locked)
> > unlock_page_lruvec_irqrestore(locked, flags);
> >
> > - compact_lock_irqsave(&lruvec->lru_lock, &flags, cc);
> > + compact_lock_irqsave(zol, &flags, cc);
> > locked = lruvec;
> >
> > lruvec_memcg_debug(lruvec, folio);
> > @@ -1555,7 +1625,7 @@ static void fast_isolate_freepages(struct
> > compact_control *cc)
> > if (!area->nr_free)
> > continue;
> >
> > - spin_lock_irqsave(&cc->zone->lock, flags);
> > + zone_lock_irqsave(cc->zone, flags);
> > freelist = &area->free_list[MIGRATE_MOVABLE];
> > list_for_each_entry_reverse(freepage, freelist, buddy_list) {
> > unsigned long pfn;
> > @@ -1614,7 +1684,7 @@ static void fast_isolate_freepages(struct
> > compact_control *cc)
> > }
> > }
> >
> > - spin_unlock_irqrestore(&cc->zone->lock, flags);
> > + zone_unlock_irqrestore(cc->zone, flags);
> >
> > /* Skip fast search if enough freepages isolated */
> > if (cc->nr_freepages >= cc->nr_migratepages)
> > @@ -1988,7 +2058,7 @@ static unsigned long fast_find_migrateblock(struct
> > compact_control *cc)
> > if (!area->nr_free)
> > continue;
> >
> > - spin_lock_irqsave(&cc->zone->lock, flags);
> > + zone_lock_irqsave(cc->zone, flags);
> > freelist = &area->free_list[MIGRATE_MOVABLE];
> > list_for_each_entry(freepage, freelist, buddy_list) {
> > unsigned long free_pfn;
> > @@ -2021,7 +2091,7 @@ static unsigned long fast_find_migrateblock(struct
> > compact_control *cc)
> > break;
> > }
> > }
> > - spin_unlock_irqrestore(&cc->zone->lock, flags);
> > + zone_unlock_irqrestore(cc->zone, flags);
> > }
> >
> > cc->total_migrate_scanned += nr_scanned;
>
