Commit a7ebf564 authored by Waiman Long's avatar Waiman Long Committed by Linus Torvalds
Browse files

mm/memcg: relocate mod_objcg_mlstate(), get_obj_stock() and put_obj_stock() 

All the calls to mod_objcg_mlstate(), get_obj_stock() and
put_obj_stock() are done by functions defined within the same "#ifdef
CONFIG_MEMCG_KMEM" compilation block.  When CONFIG_MEMCG_KMEM isn't
defined, the following compilation warnings will be issued [1] and [2].

  mm/memcontrol.c:785:20: warning: unused function 'mod_objcg_mlstate'
  mm/memcontrol.c:2113:33: warning: unused function 'get_obj_stock'

Fix these warning by moving those functions to under the same
CONFIG_MEMCG_KMEM compilation block.  There is no functional change.

[1] https://lore.kernel.org/lkml/202111272014.WOYNLUV6-lkp@intel.com/
[2] https://lore.kernel.org/lkml/202111280551.LXsWYt1T-lkp@intel.com/

Link: https://lkml.kernel.org/r/20211129161140.306488-1-longman@redhat.com


Fixes: 55927114 ("mm/memcg: optimize user context object stock access")
Fixes: 68ac5b3c ("mm/memcg: cache vmstat data in percpu memcg_stock_pcp")
Signed-off-by: default avatarWaiman Long <longman@redhat.com>
Reported-by: default avatarkernel test robot <lkp@intel.com>
Reviewed-by: default avatarShakeel Butt <shakeelb@google.com>
Acked-by: default avatarRoman Gushchin <guro@fb.com>
Reviewed-by: default avatarMuchun Song <songmuchun@bytedance.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 005a79e5

mm/memcontrol.c

+53 −53
Original line number Diff line number Diff line
@@ -776,24 +776,6 @@ void __mod_lruvec_kmem_state(void *p, enum node_stat_item idx, int val) 
	rcu_read_unlock();

}



/*

 * mod_objcg_mlstate() may be called with irq enabled, so

 * mod_memcg_lruvec_state() should be used.

 */

static inline void mod_objcg_mlstate(struct obj_cgroup *objcg,

				     struct pglist_data *pgdat,

				     enum node_stat_item idx, int nr)

{

	struct mem_cgroup *memcg;

	struct lruvec *lruvec;



	rcu_read_lock();

	memcg = obj_cgroup_memcg(objcg);

	lruvec = mem_cgroup_lruvec(memcg, pgdat);

	mod_memcg_lruvec_state(lruvec, idx, nr);

	rcu_read_unlock();

}



/**

 * __count_memcg_events - account VM events in a cgroup

 * @memcg: the memory cgroup
@@ -2137,41 +2119,6 @@ static bool obj_stock_flush_required(struct memcg_stock_pcp *stock, 
}

#endif



/*

 * Most kmem_cache_alloc() calls are from user context. The irq disable/enable

 * sequence used in this case to access content from object stock is slow.

 * To optimize for user context access, there are now two object stocks for

 * task context and interrupt context access respectively.

 *

 * The task context object stock can be accessed by disabling preemption only

 * which is cheap in non-preempt kernel. The interrupt context object stock

 * can only be accessed after disabling interrupt. User context code can

 * access interrupt object stock, but not vice versa.

 */

static inline struct obj_stock *get_obj_stock(unsigned long *pflags)

{

	struct memcg_stock_pcp *stock;



	if (likely(in_task())) {

		*pflags = 0UL;

		preempt_disable();

		stock = this_cpu_ptr(&memcg_stock);

		return &stock->task_obj;

	}



	local_irq_save(*pflags);

	stock = this_cpu_ptr(&memcg_stock);

	return &stock->irq_obj;

}



static inline void put_obj_stock(unsigned long flags)

{

	if (likely(in_task()))

		preempt_enable();

	else

		local_irq_restore(flags);

}



/**

 * consume_stock: Try to consume stocked charge on this cpu.

 * @memcg: memcg to consume from.
@@ -2816,6 +2763,59 @@ static struct mem_cgroup *get_mem_cgroup_from_objcg(struct obj_cgroup *objcg) 
 */

#define OBJCGS_CLEAR_MASK	(__GFP_DMA | __GFP_RECLAIMABLE | __GFP_ACCOUNT)



/*

 * Most kmem_cache_alloc() calls are from user context. The irq disable/enable

 * sequence used in this case to access content from object stock is slow.

 * To optimize for user context access, there are now two object stocks for

 * task context and interrupt context access respectively.

 *

 * The task context object stock can be accessed by disabling preemption only

 * which is cheap in non-preempt kernel. The interrupt context object stock

 * can only be accessed after disabling interrupt. User context code can

 * access interrupt object stock, but not vice versa.

 */

static inline struct obj_stock *get_obj_stock(unsigned long *pflags)

{

	struct memcg_stock_pcp *stock;



	if (likely(in_task())) {

		*pflags = 0UL;

		preempt_disable();

		stock = this_cpu_ptr(&memcg_stock);

		return &stock->task_obj;

	}



	local_irq_save(*pflags);

	stock = this_cpu_ptr(&memcg_stock);

	return &stock->irq_obj;

}



static inline void put_obj_stock(unsigned long flags)

{

	if (likely(in_task()))

		preempt_enable();

	else

		local_irq_restore(flags);

}



/*

 * mod_objcg_mlstate() may be called with irq enabled, so

 * mod_memcg_lruvec_state() should be used.

 */

static inline void mod_objcg_mlstate(struct obj_cgroup *objcg,

				     struct pglist_data *pgdat,

				     enum node_stat_item idx, int nr)

{

	struct mem_cgroup *memcg;

	struct lruvec *lruvec;



	rcu_read_lock();

	memcg = obj_cgroup_memcg(objcg);

	lruvec = mem_cgroup_lruvec(memcg, pgdat);

	mod_memcg_lruvec_state(lruvec, idx, nr);

	rcu_read_unlock();

}



int memcg_alloc_page_obj_cgroups(struct page *page, struct kmem_cache *s,

				 gfp_t gfp, bool new_page)

{