From 503bdc99ed7fe52b5c91469b46ea2f9fd2361350 Mon Sep 17 00:00:00 2001
From: Ingo Molnar <mingo@elte.hu>
Date: Fri, 3 Jul 2009 08:29:51 -0500
Subject: [PATCH 096/414] mm: convert swap to percpu locked

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 mm/swap.c | 34 ++++++++++++++++++++--------------
 1 file changed, 20 insertions(+), 14 deletions(-)

diff --git a/mm/swap.c b/mm/swap.c
index a8e94391b2de..0cb7d0deba9c 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -32,6 +32,7 @@
 #include <linux/gfp.h>
 #include <linux/uio.h>
 #include <linux/hugetlb.h>
+#include <linux/locallock.h>
 
 #include "internal.h"
 
@@ -45,6 +46,9 @@ static DEFINE_PER_CPU(struct pagevec, lru_add_pvec);
 static DEFINE_PER_CPU(struct pagevec, lru_rotate_pvecs);
 static DEFINE_PER_CPU(struct pagevec, lru_deactivate_pvecs);
 
+static DEFINE_LOCAL_IRQ_LOCK(rotate_lock);
+static DEFINE_LOCAL_IRQ_LOCK(swapvec_lock);
+
 /*
  * This path almost never happens for VM activity - pages are normally
  * freed via pagevecs.  But it gets used by networking.
@@ -408,11 +412,11 @@ void rotate_reclaimable_page(struct page *page)
 		unsigned long flags;
 
 		page_cache_get(page);
-		local_irq_save(flags);
+		local_lock_irqsave(rotate_lock, flags);
 		pvec = &__get_cpu_var(lru_rotate_pvecs);
 		if (!pagevec_add(pvec, page) || PageCompound(page))
 			pagevec_move_tail(pvec);
-		local_irq_restore(flags);
+		local_unlock_irqrestore(rotate_lock, flags);
 	}
 }
 
@@ -463,12 +467,13 @@ static bool need_activate_page_drain(int cpu)
 void activate_page(struct page *page)
 {
 	if (PageLRU(page) && !PageActive(page) && !PageUnevictable(page)) {
-		struct pagevec *pvec = &get_cpu_var(activate_page_pvecs);
+		struct pagevec *pvec = &get_locked_var(swapvec_lock,
+						       activate_page_pvecs);
 
 		page_cache_get(page);
 		if (!pagevec_add(pvec, page) || PageCompound(page))
 			pagevec_lru_move_fn(pvec, __activate_page, NULL);
-		put_cpu_var(activate_page_pvecs);
+		put_locked_var(swapvec_lock, activate_page_pvecs);
 	}
 }
 
@@ -494,7 +499,7 @@ void activate_page(struct page *page)
 
 static void __lru_cache_activate_page(struct page *page)
 {
-	struct pagevec *pvec = &get_cpu_var(lru_add_pvec);
+	struct pagevec *pvec = &get_locked_var(swapvec_lock, lru_add_pvec);
 	int i;
 
 	/*
@@ -516,7 +521,7 @@ static void __lru_cache_activate_page(struct page *page)
 		}
 	}
 
-	put_cpu_var(lru_add_pvec);
+	put_locked_var(swapvec_lock, lru_add_pvec);
 }
 
 /*
@@ -561,12 +566,12 @@ EXPORT_SYMBOL(init_page_accessed);
 
 static void __lru_cache_add(struct page *page)
 {
-	struct pagevec *pvec = &get_cpu_var(lru_add_pvec);
+	struct pagevec *pvec = &get_locked_var(swapvec_lock, lru_add_pvec);
 
 	page_cache_get(page);
 	if (!pagevec_add(pvec, page) || PageCompound(page))
 		__pagevec_lru_add(pvec);
-	put_cpu_var(lru_add_pvec);
+	put_locked_var(swapvec_lock, lru_add_pvec);
 }
 
 /**
@@ -712,9 +717,9 @@ void lru_add_drain_cpu(int cpu)
 		unsigned long flags;
 
 		/* No harm done if a racing interrupt already did this */
-		local_irq_save(flags);
+		local_lock_irqsave(rotate_lock, flags);
 		pagevec_move_tail(pvec);
-		local_irq_restore(flags);
+		local_unlock_irqrestore(rotate_lock, flags);
 	}
 
 	pvec = &per_cpu(lru_deactivate_pvecs, cpu);
@@ -742,18 +747,19 @@ void deactivate_page(struct page *page)
 		return;
 
 	if (likely(get_page_unless_zero(page))) {
-		struct pagevec *pvec = &get_cpu_var(lru_deactivate_pvecs);
+		struct pagevec *pvec = &get_locked_var(swapvec_lock,
+						       lru_deactivate_pvecs);
 
 		if (!pagevec_add(pvec, page) || PageCompound(page))
 			pagevec_lru_move_fn(pvec, lru_deactivate_fn, NULL);
-		put_cpu_var(lru_deactivate_pvecs);
+		put_locked_var(swapvec_lock, lru_deactivate_pvecs);
 	}
 }
 
 void lru_add_drain(void)
 {
-	lru_add_drain_cpu(get_cpu());
-	put_cpu();
+	lru_add_drain_cpu(local_lock_cpu(swapvec_lock));
+	local_unlock_cpu(swapvec_lock);
 }
 
 static void lru_add_drain_per_cpu(struct work_struct *dummy)
-- 
2.10.2

