Re: [PATCH v4 07/36] mm: introduce slabobj_ext to support slab object extensions
From: Vlastimil Babka <hidden>
Date: 2024-02-26 16:26:28
Also in:
cgroups, linux-arch, linux-doc, linux-fsdevel, linux-iommu, linux-mm, lkml
On 2/21/24 20:40, Suren Baghdasaryan wrote:
Currently slab pages can store only vectors of obj_cgroup pointers in page->memcg_data. Introduce slabobj_ext structure to allow more data to be stored for each slab object. Wrap obj_cgroup into slabobj_ext to support current functionality while allowing to extend slabobj_ext in the future. Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Hi, mostly good from slab perspective, just some fixups:
quoted hunk ↗ jump to hunk
--- a/mm/slab.h +++ b/mm/slab.h -int memcg_alloc_slab_cgroups(struct slab *slab, struct kmem_cache *s, - gfp_t gfp, bool new_slab); -void mod_objcg_state(struct obj_cgroup *objcg, struct pglist_data *pgdat, - enum node_stat_item idx, int nr); -#else /* CONFIG_MEMCG_KMEM */ -static inline struct obj_cgroup **slab_objcgs(struct slab *slab) +int alloc_slab_obj_exts(struct slab *slab, struct kmem_cache *s, + gfp_t gfp, bool new_slab);
We could remove this declaration and make the function static in mm/slub.c.
+#else /* CONFIG_SLAB_OBJ_EXT */
+
+static inline struct slabobj_ext *slab_obj_exts(struct slab *slab)
{
return NULL;
}
-static inline int memcg_alloc_slab_cgroups(struct slab *slab,
- struct kmem_cache *s, gfp_t gfp,
- bool new_slab)
+static inline int alloc_slab_obj_exts(struct slab *slab,
+ struct kmem_cache *s, gfp_t gfp,
+ bool new_slab)
{
return 0;
}Ditto
-#endif /* CONFIG_MEMCG_KMEM */
+
+static inline struct slabobj_ext *
+prepare_slab_obj_exts_hook(struct kmem_cache *s, gfp_t flags, void *p)
+{
+ return NULL;
+}Same here (and the definition and usage even happens in later patch).
quoted hunk ↗ jump to hunk
+#endif /* CONFIG_SLAB_OBJ_EXT */ + +#ifdef CONFIG_MEMCG_KMEM +void mod_objcg_state(struct obj_cgroup *objcg, struct pglist_data *pgdat, + enum node_stat_item idx, int nr); +#endif size_t __ksize(const void *objp);diff --git a/mm/slub.c b/mm/slub.c index d31b03a8d9d5..76fb600fbc80 100644 --- a/mm/slub.c +++ b/mm/slub.c@@ -683,10 +683,10 @@ static inline bool __slab_update_freelist(struct kmem_cache *s, struct slab *sla if (s->flags & __CMPXCHG_DOUBLE) { ret = __update_freelist_fast(slab, freelist_old, counters_old, - freelist_new, counters_new); + freelist_new, counters_new); } else { ret = __update_freelist_slow(slab, freelist_old, counters_old, - freelist_new, counters_new); + freelist_new, counters_new); } if (likely(ret)) return true;@@ -710,13 +710,13 @@ static inline bool slab_update_freelist(struct kmem_cache *s, struct slab *slab, if (s->flags & __CMPXCHG_DOUBLE) { ret = __update_freelist_fast(slab, freelist_old, counters_old, - freelist_new, counters_new); + freelist_new, counters_new); } else { unsigned long flags; local_irq_save(flags); ret = __update_freelist_slow(slab, freelist_old, counters_old, - freelist_new, counters_new); + freelist_new, counters_new);
Please no drive-by fixups of whitespace in code you're not actually changing. I thought you agreed in v3?
quoted hunk ↗ jump to hunk
static inline bool memcg_slab_pre_alloc_hook(struct kmem_cache *s, struct list_lru *lru, struct obj_cgroup **objcgp,@@ -2314,7 +2364,7 @@ static __always_inline void account_slab(struct slab *slab, int order, struct kmem_cache *s, gfp_t gfp) { if (memcg_kmem_online() && (s->flags & SLAB_ACCOUNT)) - memcg_alloc_slab_cgroups(slab, s, gfp, true); + alloc_slab_obj_exts(slab, s, gfp, true);
This is still guarded by the memcg_kmem_online() static key, which is good.
quoted hunk ↗ jump to hunk
mod_node_page_state(slab_pgdat(slab), cache_vmstat_idx(s), PAGE_SIZE << order);@@ -2323,8 +2373,7 @@ static __always_inline void account_slab(struct slab *slab, int order, static __always_inline void unaccount_slab(struct slab *slab, int order, struct kmem_cache *s) { - if (memcg_kmem_online()) - memcg_free_slab_cgroups(slab); + free_slab_obj_exts(slab);
But this no longer is, yet it still could be?
mod_node_page_state(slab_pgdat(slab), cache_vmstat_idx(s), -(PAGE_SIZE << order));