text: From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
  Subject: mm/memcontrol: Replace local_irq_disable with local locks
  Date: Wed, 28 Jan 2015 17:14:16 +0100
  
  There are a few local_irq_disable() which then take sleeping locks. This
  patch converts them local locks.
  
  Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
  ---
   mm/memcontrol.c |   24 ++++++++++++++++--------
   1 file changed, 16 insertions(+), 8 deletions(-)
  
  --- a/mm/memcontrol.c
  +++ b/mm/memcontrol.c
  @@ -63,6 +63,7 @@
   #include <net/sock.h>
   #include <net/ip.h>
   #include "slab.h"
  +#include <linux/locallock.h>
   
   #include <linux/uaccess.h>
   
  @@ -92,6 +93,8 @@ int do_swap_account __read_mostly;
   static DECLARE_WAIT_QUEUE_HEAD(memcg_cgwb_frn_waitq);
   #endif
   
  +static DEFINE_LOCAL_IRQ_LOCK(event_lock);
  +
   /* Whether legacy memory+swap accounting is active */
   static bool do_memsw_account(void)
   {
  @@ -5509,12 +5512,12 @@ static int mem_cgroup_move_account(struc
   
   	ret = 0;
   
  -	local_irq_disable();
  +	local_lock_irq(event_lock);
   	mem_cgroup_charge_statistics(to, page, compound, nr_pages);
   	memcg_check_events(to, page);
   	mem_cgroup_charge_statistics(from, page, compound, -nr_pages);
   	memcg_check_events(from, page);
  -	local_irq_enable();
  +	local_unlock_irq(event_lock);
   out_unlock:
   	unlock_page(page);
   out:
  @@ -6562,10 +6565,10 @@ void mem_cgroup_commit_charge(struct pag
   
   	commit_charge(page, memcg, lrucare);
   
  -	local_irq_disable();
  +	local_lock_irq(event_lock);
   	mem_cgroup_charge_statistics(memcg, page, compound, nr_pages);
   	memcg_check_events(memcg, page);
  -	local_irq_enable();
  +	local_unlock_irq(event_lock);
   
   	if (do_memsw_account() && PageSwapCache(page)) {
   		swp_entry_t entry = { .val = page_private(page) };
  @@ -6634,7 +6637,7 @@ static void uncharge_batch(const struct
   		memcg_oom_recover(ug->memcg);
   	}
   
  -	local_irq_save(flags);
  +	local_lock_irqsave(event_lock, flags);
   	__mod_memcg_state(ug->memcg, MEMCG_RSS, -ug->nr_anon);
   	__mod_memcg_state(ug->memcg, MEMCG_CACHE, -ug->nr_file);
   	__mod_memcg_state(ug->memcg, MEMCG_RSS_HUGE, -ug->nr_huge);
  @@ -6642,7 +6645,7 @@ static void uncharge_batch(const struct
   	__count_memcg_events(ug->memcg, PGPGOUT, ug->pgpgout);
   	__this_cpu_add(ug->memcg->vmstats_percpu->nr_page_events, nr_pages);
   	memcg_check_events(ug->memcg, ug->dummy_page);
  -	local_irq_restore(flags);
  +	local_unlock_irqrestore(event_lock, flags);
   
   	if (!mem_cgroup_is_root(ug->memcg))
   		css_put_many(&ug->memcg->css, nr_pages);
  @@ -6805,10 +6808,10 @@ void mem_cgroup_migrate(struct page *old
   
   	commit_charge(newpage, memcg, false);
   
  -	local_irq_save(flags);
  +	local_lock_irqsave(event_lock, flags);
   	mem_cgroup_charge_statistics(memcg, newpage, compound, nr_pages);
   	memcg_check_events(memcg, newpage);
  -	local_irq_restore(flags);
  +	local_unlock_irqrestore(event_lock, flags);
   }
   
   DEFINE_STATIC_KEY_FALSE(memcg_sockets_enabled_key);
  @@ -6990,6 +6993,7 @@ void mem_cgroup_swapout(struct page *pag
   	struct mem_cgroup *memcg, *swap_memcg;
   	unsigned int nr_entries;
   	unsigned short oldid;
  +	unsigned long flags;
   
   	VM_BUG_ON_PAGE(PageLRU(page), page);
   	VM_BUG_ON_PAGE(page_count(page), page);
  @@ -7035,13 +7039,17 @@ void mem_cgroup_swapout(struct page *pag
   	 * important here to have the interrupts disabled because it is the
   	 * only synchronisation we have for updating the per-CPU variables.
   	 */
  +	local_lock_irqsave(event_lock, flags);
  +#ifndef CONFIG_PREEMPT_RT
   	VM_BUG_ON(!irqs_disabled());
  +#endif
   	mem_cgroup_charge_statistics(memcg, page, PageTransHuge(page),
   				     -nr_entries);
   	memcg_check_events(memcg, page);
   
   	if (!mem_cgroup_is_root(memcg))
   		css_put_many(&memcg->css, nr_entries);
  +	local_unlock_irqrestore(event_lock, flags);
   }
   
   /**
  