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Diffstat (limited to 'mm/kasan/quarantine.c')
-rw-r--r--mm/kasan/quarantine.c94
1 files changed, 48 insertions, 46 deletions
diff --git a/mm/kasan/quarantine.c b/mm/kasan/quarantine.c
index baabaad4a4aa..dae929c02bbb 100644
--- a/mm/kasan/quarantine.c
+++ b/mm/kasan/quarantine.c
@@ -86,24 +86,9 @@ static void qlist_move_all(struct qlist_head *from, struct qlist_head *to)
qlist_init(from);
}
-static void qlist_move(struct qlist_head *from, struct qlist_node *last,
- struct qlist_head *to, size_t size)
-{
- if (unlikely(last == from->tail)) {
- qlist_move_all(from, to);
- return;
- }
- if (qlist_empty(to))
- to->head = from->head;
- else
- to->tail->next = from->head;
- to->tail = last;
- from->head = last->next;
- last->next = NULL;
- from->bytes -= size;
- to->bytes += size;
-}
-
+#define QUARANTINE_PERCPU_SIZE (1 << 20)
+#define QUARANTINE_BATCHES \
+ (1024 > 4 * CONFIG_NR_CPUS ? 1024 : 4 * CONFIG_NR_CPUS)
/*
* The object quarantine consists of per-cpu queues and a global queue,
@@ -111,11 +96,22 @@ static void qlist_move(struct qlist_head *from, struct qlist_node *last,
*/
static DEFINE_PER_CPU(struct qlist_head, cpu_quarantine);
-static struct qlist_head global_quarantine;
+/* Round-robin FIFO array of batches. */
+static struct qlist_head global_quarantine[QUARANTINE_BATCHES];
+static int quarantine_head;
+static int quarantine_tail;
+/* Total size of all objects in global_quarantine across all batches. */
+static unsigned long quarantine_size;
static DEFINE_SPINLOCK(quarantine_lock);
/* Maximum size of the global queue. */
-static unsigned long quarantine_size;
+static unsigned long quarantine_max_size;
+
+/*
+ * Target size of a batch in global_quarantine.
+ * Usually equal to QUARANTINE_PERCPU_SIZE unless we have too much RAM.
+ */
+static unsigned long quarantine_batch_size;
/*
* The fraction of physical memory the quarantine is allowed to occupy.
@@ -124,9 +120,6 @@ static unsigned long quarantine_size;
*/
#define QUARANTINE_FRACTION 32
-#define QUARANTINE_LOW_SIZE (READ_ONCE(quarantine_size) * 3 / 4)
-#define QUARANTINE_PERCPU_SIZE (1 << 20)
-
static struct kmem_cache *qlink_to_cache(struct qlist_node *qlink)
{
return virt_to_head_page(qlink)->slab_cache;
@@ -191,21 +184,30 @@ void quarantine_put(struct kasan_free_meta *info, struct kmem_cache *cache)
if (unlikely(!qlist_empty(&temp))) {
spin_lock_irqsave(&quarantine_lock, flags);
- qlist_move_all(&temp, &global_quarantine);
+ WRITE_ONCE(quarantine_size, quarantine_size + temp.bytes);
+ qlist_move_all(&temp, &global_quarantine[quarantine_tail]);
+ if (global_quarantine[quarantine_tail].bytes >=
+ READ_ONCE(quarantine_batch_size)) {
+ int new_tail;
+
+ new_tail = quarantine_tail + 1;
+ if (new_tail == QUARANTINE_BATCHES)
+ new_tail = 0;
+ if (new_tail != quarantine_head)
+ quarantine_tail = new_tail;
+ }
spin_unlock_irqrestore(&quarantine_lock, flags);
}
}
void quarantine_reduce(void)
{
- size_t new_quarantine_size, percpu_quarantines;
+ size_t total_size, new_quarantine_size, percpu_quarantines;
unsigned long flags;
struct qlist_head to_free = QLIST_INIT;
- size_t size_to_free = 0;
- struct qlist_node *last;
- if (likely(READ_ONCE(global_quarantine.bytes) <=
- READ_ONCE(quarantine_size)))
+ if (likely(READ_ONCE(quarantine_size) <=
+ READ_ONCE(quarantine_max_size)))
return;
spin_lock_irqsave(&quarantine_lock, flags);
@@ -214,24 +216,23 @@ void quarantine_reduce(void)
* Update quarantine size in case of hotplug. Allocate a fraction of
* the installed memory to quarantine minus per-cpu queue limits.
*/
- new_quarantine_size = (READ_ONCE(totalram_pages) << PAGE_SHIFT) /
+ total_size = (READ_ONCE(totalram_pages) << PAGE_SHIFT) /
QUARANTINE_FRACTION;
percpu_quarantines = QUARANTINE_PERCPU_SIZE * num_online_cpus();
- new_quarantine_size = (new_quarantine_size < percpu_quarantines) ?
- 0 : new_quarantine_size - percpu_quarantines;
- WRITE_ONCE(quarantine_size, new_quarantine_size);
-
- last = global_quarantine.head;
- while (last) {
- struct kmem_cache *cache = qlink_to_cache(last);
-
- size_to_free += cache->size;
- if (!last->next || size_to_free >
- global_quarantine.bytes - QUARANTINE_LOW_SIZE)
- break;
- last = last->next;
+ new_quarantine_size = (total_size < percpu_quarantines) ?
+ 0 : total_size - percpu_quarantines;
+ WRITE_ONCE(quarantine_max_size, new_quarantine_size);
+ /* Aim at consuming at most 1/2 of slots in quarantine. */
+ WRITE_ONCE(quarantine_batch_size, max((size_t)QUARANTINE_PERCPU_SIZE,
+ 2 * total_size / QUARANTINE_BATCHES));
+
+ if (likely(quarantine_size > quarantine_max_size)) {
+ qlist_move_all(&global_quarantine[quarantine_head], &to_free);
+ WRITE_ONCE(quarantine_size, quarantine_size - to_free.bytes);
+ quarantine_head++;
+ if (quarantine_head == QUARANTINE_BATCHES)
+ quarantine_head = 0;
}
- qlist_move(&global_quarantine, last, &to_free, size_to_free);
spin_unlock_irqrestore(&quarantine_lock, flags);
@@ -275,13 +276,14 @@ static void per_cpu_remove_cache(void *arg)
void quarantine_remove_cache(struct kmem_cache *cache)
{
- unsigned long flags;
+ unsigned long flags, i;
struct qlist_head to_free = QLIST_INIT;
on_each_cpu(per_cpu_remove_cache, cache, 1);
spin_lock_irqsave(&quarantine_lock, flags);
- qlist_move_cache(&global_quarantine, &to_free, cache);
+ for (i = 0; i < QUARANTINE_BATCHES; i++)
+ qlist_move_cache(&global_quarantine[i], &to_free, cache);
spin_unlock_irqrestore(&quarantine_lock, flags);
qlist_free_all(&to_free, cache);