mm: memcg/slab: use a single set of kmem_caches for all allocations

Instead of having two sets of kmem_caches: one for system-wide and non-accounted allocations and the second one shared by all accounted allocations, we can use just one. The idea is simple: space for obj_cgroup metadata can be allocated on demand and filled only for accounted allocations. It allows to remove a bunch of code which is required to handle kmem_cache clones for accounted allocations. There is no more need to create them, accumulate statistics, propagate attributes, etc. It's a quite significant simplification. Also, because the total number of slab_caches is reduced almost twice (not all kmem_caches have a memcg clone), some additional memory savings are expected. On my devvm it additionally saves about 3.5% of slab memory. [guro@fb.com: fix build on MIPS] Link: http://lkml.kernel.org/r/20200717214810.3733082-1-guro@fb.com

Roman Gushchin committed 6 years ago

Commit 10befea1 parent 15999ee8 files · +78 −590Browse files

Showing the changes to include/linux (3 of 8 files). Show all

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3 files

include/linux/slab.h +0 −2
include/linux/slab_def.h +0 −3
include/linux/slub_def.h +0 −10

include/linux/slab.h+0−2

@@ -155,8 +155,6 @@ struct kmem_cache kmem_cache_create_usercopy(const char name, · 154 unmodified lines
155	155	void kmem_cache_destroy(struct kmem_cache *);
156	156	int kmem_cache_shrink(struct kmem_cache *);
157	157
158		−void memcg_create_kmem_cache(struct kmem_cache *cachep);
159		−
160	158	/*
161	159	* Please use this macro to create slab caches. Simply specify the
162	160	* name of the structure and maybe some flags that are listed above.

include/linux/slab_def.h+0−3

@@ -72,9 +72,6 @@ struct kmem_cache { · 71 unmodified lines
72	72	int obj_offset;
73	73	#endif /* CONFIG_DEBUG_SLAB */
74	74
75		−#ifdef CONFIG_MEMCG
76		− struct memcg_cache_params memcg_params;
77		−#endif
78	75	#ifdef CONFIG_KASAN
79	76	struct kasan_cache kasan_info;
80	77	#endif

include/linux/slub_def.h+0−10

@@ -108,17 +108,7 @@ struct kmem_cache { · 107 unmodified lines
108	108	struct list_head list; /* List of slab caches */
109	109	#ifdef CONFIG_SYSFS
110	110	struct kobject kobj; /* For sysfs */
111		− struct work_struct kobj_remove_work;
112	111	#endif
113		−#ifdef CONFIG_MEMCG
114		− struct memcg_cache_params memcg_params;
115		− /* For propagation, maximum size of a stored attr */
116		− unsigned int max_attr_size;
117		−#ifdef CONFIG_SYSFS
118		− struct kset *memcg_kset;
119		−#endif
120		−#endif
121		−
122	112	#ifdef CONFIG_SLAB_FREELIST_HARDENED
123	113	unsigned long random;
124	114	#endif