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);
 }
 
 /**
