Commit e93d4166 authored by Roman Gushchin's avatar Roman Gushchin Committed by Andrew Morton
Browse files

mm: memcg: put cgroup v1-specific code under a config option 

Put legacy cgroup v1 memory controller code under a new CONFIG_MEMCG_V1
config option.  The option is turned off by default.  Nobody except those
who are still using cgroup v1 should turn it on.

If the option is not set, memory controller can still be mounted under
cgroup v1, but none of memcg-specific control files are present.

Please note, that not all cgroup v1's memory controller code is guarded
yet (but most of it), it's a subject for some follow-up work.

Thanks to Michal Hocko for providing a better Kconfig option description.

[roman.gushchin@linux.dev: better config option description provided by Michal]
  Link: https://lkml.kernel.org/r/ZnxXNtvqllc9CDoo@google.com
Link: https://lkml.kernel.org/r/20240625005906.106920-14-roman.gushchin@linux.dev


Signed-off-by: default avatarRoman Gushchin <roman.gushchin@linux.dev>
Acked-by: default avatarMichal Hocko <mhocko@suse.com>
Acked-by: default avatarShakeel Butt <shakeel.butt@linux.dev>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Muchun Song <muchun.song@linux.dev>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 6f1173d6

include/linux/memcontrol.h

+3 −3
Original line number Diff line number Diff line
@@ -1851,7 +1851,7 @@ static inline bool mem_cgroup_zswap_writeback_enabled(struct mem_cgroup *memcg) 


/* Cgroup v1-related declarations */



#ifdef CONFIG_MEMCG

#ifdef CONFIG_MEMCG_V1

unsigned long memcg1_soft_limit_reclaim(pg_data_t *pgdat, int order,

					gfp_t gfp_mask,

					unsigned long *total_scanned);
@@ -1883,7 +1883,7 @@ static inline void mem_cgroup_unlock_pages(void) 
	rcu_read_unlock();

}



#else /* CONFIG_MEMCG */

#else /* CONFIG_MEMCG_V1 */

static inline

unsigned long memcg1_soft_limit_reclaim(pg_data_t *pgdat, int order,

					gfp_t gfp_mask,
@@ -1922,6 +1922,6 @@ static inline bool mem_cgroup_oom_synchronize(bool wait) 
	return false;

}



#endif /* CONFIG_MEMCG */

#endif /* CONFIG_MEMCG_V1 */



#endif /* _LINUX_MEMCONTROL_H */

init/Kconfig

+17 −0
Original line number Diff line number Diff line
@@ -969,6 +969,23 @@ config MEMCG 
	help

	  Provides control over the memory footprint of tasks in a cgroup.



config MEMCG_V1

	bool "Legacy cgroup v1 memory controller"

	depends on MEMCG

	default n

	help

	  Legacy cgroup v1 memory controller which has been deprecated by

	  cgroup v2 implementation. The v1 is there for legacy applications

	  which haven't migrated to the new cgroup v2 interface yet. If you

	  do not have any such application then you are completely fine leaving

	  this option disabled.



	  Please note that feature set of the legacy memory controller is likely

	  going to shrink due to deprecation process. New deployments with v1

	  controller are highly discouraged.



	  San N is unsure.



config MEMCG_KMEM

	bool

	depends on MEMCG

mm/Makefile

+2 −1
Original line number Diff line number Diff line
@@ -96,7 +96,8 @@ obj-$(CONFIG_NUMA) += memory-tiers.o 
obj-$(CONFIG_DEVICE_MIGRATION) += migrate_device.o

obj-$(CONFIG_TRANSPARENT_HUGEPAGE) += huge_memory.o khugepaged.o

obj-$(CONFIG_PAGE_COUNTER) += page_counter.o

obj-$(CONFIG_MEMCG) += memcontrol.o memcontrol-v1.o vmpressure.o

obj-$(CONFIG_MEMCG_V1) += memcontrol-v1.o

obj-$(CONFIG_MEMCG) += memcontrol.o vmpressure.o

ifdef CONFIG_SWAP

obj-$(CONFIG_MEMCG) += swap_cgroup.o

endif

mm/memcontrol-v1.h

+20 −1
Original line number Diff line number Diff line
@@ -70,7 +70,7 @@ unsigned long memcg_page_state_local_output(struct mem_cgroup *memcg, int item); 
int memory_stat_show(struct seq_file *m, void *v);



/* Cgroup v1-specific declarations */



#ifdef CONFIG_MEMCG_V1

void memcg1_remove_from_trees(struct mem_cgroup *memcg);



static inline void memcg1_soft_limit_reset(struct mem_cgroup *memcg)
@@ -105,4 +105,23 @@ void memcg1_stat_format(struct mem_cgroup *memcg, struct seq_buf *s); 
extern struct cftype memsw_files[];

extern struct cftype mem_cgroup_legacy_files[];



#else	/* CONFIG_MEMCG_V1 */



static inline void memcg1_remove_from_trees(struct mem_cgroup *memcg) {}

static inline void memcg1_soft_limit_reset(struct mem_cgroup *memcg) {}

static inline bool memcg1_wait_acct_move(struct mem_cgroup *memcg) { return false; }

static inline void memcg1_css_offline(struct mem_cgroup *memcg) {}



static inline bool memcg1_oom_prepare(struct mem_cgroup *memcg, bool *locked) { return true; }

static inline void memcg1_oom_finish(struct mem_cgroup *memcg, bool locked) {}

static inline void memcg1_oom_recover(struct mem_cgroup *memcg) {}



static inline void memcg1_check_events(struct mem_cgroup *memcg, int nid) {}



static inline void memcg1_stat_format(struct mem_cgroup *memcg, struct seq_buf *s) {}



extern struct cftype memsw_files[];

extern struct cftype mem_cgroup_legacy_files[];

#endif	/* CONFIG_MEMCG_V1 */



#endif	/* __MM_MEMCONTROL_V1_H */

mm/memcontrol.c

+7 −3
Original line number Diff line number Diff line
@@ -4398,18 +4398,20 @@ struct cgroup_subsys memory_cgrp_subsys = { 
	.css_free = mem_cgroup_css_free,

	.css_reset = mem_cgroup_css_reset,

	.css_rstat_flush = mem_cgroup_css_rstat_flush,

	.can_attach = memcg1_can_attach,

#if defined(CONFIG_LRU_GEN) || defined(CONFIG_MEMCG_KMEM)

	.attach = mem_cgroup_attach,

#endif

	.cancel_attach = memcg1_cancel_attach,

	.post_attach = memcg1_move_task,

#ifdef CONFIG_MEMCG_KMEM

	.fork = mem_cgroup_fork,

	.exit = mem_cgroup_exit,

#endif

	.dfl_cftypes = memory_files,

#ifdef CONFIG_MEMCG_V1

	.can_attach = memcg1_can_attach,

	.cancel_attach = memcg1_cancel_attach,

	.post_attach = memcg1_move_task,

	.legacy_cftypes = mem_cgroup_legacy_files,

#endif

	.early_init = 0,

};
@@ -5581,7 +5583,9 @@ static int __init mem_cgroup_swap_init(void) 
		return 0;



	WARN_ON(cgroup_add_dfl_cftypes(&memory_cgrp_subsys, swap_files));

#ifdef CONFIG_MEMCG_V1

	WARN_ON(cgroup_add_legacy_cftypes(&memory_cgrp_subsys, memsw_files));

#endif

#if defined(CONFIG_MEMCG_KMEM) && defined(CONFIG_ZSWAP)

	WARN_ON(cgroup_add_dfl_cftypes(&memory_cgrp_subsys, zswap_files));

#endif