linux-kernel - [PATCH 1/1] mm/vmalloc: convert vmap_lazy_nr to atomic_long

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Date:   Thu, 31 Jan 2019 17:24:52 +0100
From:   "Uladzislau Rezki (Sony)" <urezki@...il.com>
To:     Andrew Morton <akpm@...ux-foundation.org>
Cc:     linux-mm@...ck.org, Michal Hocko <mhocko@...e.com>,
        Matthew Wilcox <willy@...radead.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Thomas Garnier <thgarnie@...gle.com>,
        Oleksiy Avramchenko <oleksiy.avramchenko@...ymobile.com>,
        Steven Rostedt <rostedt@...dmis.org>,
        Joel Fernandes <joelaf@...gle.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...e.hu>, Tejun Heo <tj@...nel.org>,
        "Uladzislau Rezki (Sony)" <urezki@...il.com>
Subject: [PATCH 1/1] mm/vmalloc: convert vmap_lazy_nr to atomic_long_t

vmap_lazy_nr variable has atomic_t type that is 4 bytes integer
value on both 32 and 64 bit systems. lazy_max_pages() deals with
"unsigned long" that is 8 bytes on 64 bit system, thus vmap_lazy_nr
should be 8 bytes on 64 bit as well.

Signed-off-by: Uladzislau Rezki (Sony) <urezki@...il.com>
---
 mm/vmalloc.c | 20 ++++++++++----------
 1 file changed, 10 insertions(+), 10 deletions(-)

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index abe83f885069..755b02983d8d 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -632,7 +632,7 @@ static unsigned long lazy_max_pages(void)
 	return log * (32UL * 1024 * 1024 / PAGE_SIZE);
 }
 
-static atomic_t vmap_lazy_nr = ATOMIC_INIT(0);
+static atomic_long_t vmap_lazy_nr = ATOMIC_LONG_INIT(0);
 
 /*
  * Serialize vmap purging.  There is no actual criticial section protected
@@ -650,7 +650,7 @@ static void purge_fragmented_blocks_allcpus(void);
  */
 void set_iounmap_nonlazy(void)
 {
-	atomic_set(&vmap_lazy_nr, lazy_max_pages()+1);
+	atomic_long_set(&vmap_lazy_nr, lazy_max_pages()+1);
 }
 
 /*
@@ -658,10 +658,10 @@ void set_iounmap_nonlazy(void)
  */
 static bool __purge_vmap_area_lazy(unsigned long start, unsigned long end)
 {
+	unsigned long resched_threshold;
 	struct llist_node *valist;
 	struct vmap_area *va;
 	struct vmap_area *n_va;
-	int resched_threshold;
 
 	lockdep_assert_held(&vmap_purge_lock);
 
@@ -681,16 +681,16 @@ static bool __purge_vmap_area_lazy(unsigned long start, unsigned long end)
 	}
 
 	flush_tlb_kernel_range(start, end);
-	resched_threshold = (int) lazy_max_pages() << 1;
+	resched_threshold = lazy_max_pages() << 1;
 
 	spin_lock(&vmap_area_lock);
 	llist_for_each_entry_safe(va, n_va, valist, purge_list) {
-		int nr = (va->va_end - va->va_start) >> PAGE_SHIFT;
+		unsigned long nr = (va->va_end - va->va_start) >> PAGE_SHIFT;
 
 		__free_vmap_area(va);
-		atomic_sub(nr, &vmap_lazy_nr);
+		atomic_long_sub(nr, &vmap_lazy_nr);
 
-		if (atomic_read(&vmap_lazy_nr) < resched_threshold)
+		if (atomic_long_read(&vmap_lazy_nr) < resched_threshold)
 			cond_resched_lock(&vmap_area_lock);
 	}
 	spin_unlock(&vmap_area_lock);
@@ -727,10 +727,10 @@ static void purge_vmap_area_lazy(void)
  */
 static void free_vmap_area_noflush(struct vmap_area *va)
 {
-	int nr_lazy;
+	unsigned long nr_lazy;
 
-	nr_lazy = atomic_add_return((va->va_end - va->va_start) >> PAGE_SHIFT,
-				    &vmap_lazy_nr);
+	nr_lazy = atomic_long_add_return((va->va_end - va->va_start) >>
+				PAGE_SHIFT, &vmap_lazy_nr);
 
 	/* After this point, we may free va at any time */
 	llist_add(&va->purge_list, &vmap_purge_list);
-- 
2.11.0