There are no more cpu slabs so we don't need their deferred deactivation. The function is now only used from a place where we allocate a new slab but then can't spin on node list_lock to put it on the partial list. Instead of the deferred action we can free it directly via __free_slab(), we just need to tell it to use _nolock() freeing of the underlying pages and take care of the accounting. Since free_frozen_pages_nolock() variant does not yet exist for code outside of the page allocator, create it as a trivial wrapper for __free_frozen_pages(..., FPI_TRYLOCK). Signed-off-by: Vlastimil Babka --- mm/internal.h | 1 + mm/page_alloc.c | 5 +++++ mm/slab.h | 8 +------- mm/slub.c | 50 +++++++++++++++----------------------------------- 4 files changed, 22 insertions(+), 42 deletions(-) diff --git a/mm/internal.h b/mm/internal.h index 1561fc2ff5b8..64c5eda7c1ae 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -846,6 +846,7 @@ static inline struct page *alloc_frozen_pages_noprof(gfp_t gfp, unsigned int ord struct page *alloc_frozen_pages_nolock_noprof(gfp_t gfp_flags, int nid, unsigned int order); #define alloc_frozen_pages_nolock(...) \ alloc_hooks(alloc_frozen_pages_nolock_noprof(__VA_ARGS__)) +void free_frozen_pages_nolock(struct page *page, unsigned int order); extern void zone_pcp_reset(struct zone *zone); extern void zone_pcp_disable(struct zone *zone); diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 600d9e981c23..f8ac3232db41 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -2944,6 +2944,11 @@ void free_frozen_pages(struct page *page, unsigned int order) __free_frozen_pages(page, order, FPI_NONE); } +void free_frozen_pages_nolock(struct page *page, unsigned int order) +{ + __free_frozen_pages(page, order, FPI_TRYLOCK); +} + /* * Free a batch of folios */ diff --git a/mm/slab.h b/mm/slab.h index a103da44ab9d..b2663cc594f3 100644 --- a/mm/slab.h +++ b/mm/slab.h @@ -55,13 +55,7 @@ struct slab { struct kmem_cache *slab_cache; union { struct { - union { - struct list_head slab_list; - struct { /* For deferred deactivate_slab() */ - struct llist_node llnode; - void *flush_freelist; - }; - }; + struct list_head slab_list; /* Double-word boundary */ union { struct { diff --git a/mm/slub.c b/mm/slub.c index a35eb397caa9..6f5ca26bbb00 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -3246,7 +3246,7 @@ static struct slab *new_slab(struct kmem_cache *s, gfp_t flags, int node) flags & (GFP_RECLAIM_MASK | GFP_CONSTRAINT_MASK), node); } -static void __free_slab(struct kmem_cache *s, struct slab *slab) +static void __free_slab(struct kmem_cache *s, struct slab *slab, bool allow_spin) { struct folio *folio = slab_folio(slab); int order = folio_order(folio); @@ -3257,14 +3257,18 @@ static void __free_slab(struct kmem_cache *s, struct slab *slab) __folio_clear_slab(folio); mm_account_reclaimed_pages(pages); unaccount_slab(slab, order, s); - free_frozen_pages(&folio->page, order); + + if (allow_spin) + free_frozen_pages(&folio->page, order); + else + free_frozen_pages_nolock(&folio->page, order); } static void rcu_free_slab(struct rcu_head *h) { struct slab *slab = container_of(h, struct slab, rcu_head); - __free_slab(slab->slab_cache, slab); + __free_slab(slab->slab_cache, slab, true); } static void free_slab(struct kmem_cache *s, struct slab *slab) @@ -3280,7 +3284,7 @@ static void free_slab(struct kmem_cache *s, struct slab *slab) if (unlikely(s->flags & SLAB_TYPESAFE_BY_RCU)) call_rcu(&slab->rcu_head, rcu_free_slab); else - __free_slab(s, slab); + __free_slab(s, slab, true); } static void discard_slab(struct kmem_cache *s, struct slab *slab) @@ -3373,8 +3377,6 @@ static void *alloc_single_from_partial(struct kmem_cache *s, return object; } -static void defer_deactivate_slab(struct slab *slab, void *flush_freelist); - /* * Called only for kmem_cache_debug() caches to allocate from a freshly * allocated slab. Allocate a single object instead of whole freelist @@ -3390,8 +3392,12 @@ static void *alloc_single_from_new_slab(struct kmem_cache *s, struct slab *slab, void *object; if (!allow_spin && !spin_trylock_irqsave(&n->list_lock, flags)) { - /* Unlucky, discard newly allocated slab */ - defer_deactivate_slab(slab, NULL); + /* + * Unlucky, discard newly allocated slab. + * Since it was just allocated, we can skip the actions + * in discard_slab() and free_slab(). + */ + __free_slab(s, slab, false); return NULL; } @@ -5949,7 +5955,6 @@ static void free_to_pcs_bulk(struct kmem_cache *s, size_t size, void **p) struct defer_free { struct llist_head objects; - struct llist_head slabs; struct irq_work work; }; @@ -5957,7 +5962,6 @@ static void free_deferred_objects(struct irq_work *work); static DEFINE_PER_CPU(struct defer_free, defer_free_objects) = { .objects = LLIST_HEAD_INIT(objects), - .slabs = LLIST_HEAD_INIT(slabs), .work = IRQ_WORK_INIT(free_deferred_objects), }; @@ -5970,10 +5974,9 @@ static void free_deferred_objects(struct irq_work *work) { struct defer_free *df = container_of(work, struct defer_free, work); struct llist_head *objs = &df->objects; - struct llist_head *slabs = &df->slabs; struct llist_node *llnode, *pos, *t; - if (llist_empty(objs) && llist_empty(slabs)) + if (llist_empty(objs)) return; llnode = llist_del_all(objs); @@ -5997,16 +6000,6 @@ static void free_deferred_objects(struct irq_work *work) __slab_free(s, slab, x, x, 1, _THIS_IP_); } - - llnode = llist_del_all(slabs); - llist_for_each_safe(pos, t, llnode) { - struct slab *slab = container_of(pos, struct slab, llnode); - - if (slab->frozen) - deactivate_slab(slab->slab_cache, slab, slab->flush_freelist); - else - free_slab(slab->slab_cache, slab); - } } static void defer_free(struct kmem_cache *s, void *head) @@ -6020,19 +6013,6 @@ static void defer_free(struct kmem_cache *s, void *head) irq_work_queue(&df->work); } -static void defer_deactivate_slab(struct slab *slab, void *flush_freelist) -{ - struct defer_free *df; - - slab->flush_freelist = flush_freelist; - - guard(preempt)(); - - df = this_cpu_ptr(&defer_free_objects); - if (llist_add(&slab->llnode, &df->slabs)) - irq_work_queue(&df->work); -} - void defer_free_barrier(void) { int cpu; -- 2.51.1