dm bufio: remove old-style buffer cleanup

Remove code that cleans up buffers if the cache size grows over the limit.

The next commit will introduce a new global cleanup.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

diff --git a/drivers/md/dm-bufio.c b/drivers/md/dm-bufio.c
index 2451a4d68aed2caaf592c8b67f45875c4f77be57..c0647cce2128f39421c45f280e2b37862425ada5 100644 (file)
--- a/drivers/md/dm-bufio.c
+++ b/drivers/md/dm-bufio.c
@@ -33,7 +33,7 @@
 
 #define DM_BUFIO_MEMORY_PERCENT                2
 #define DM_BUFIO_VMALLOC_PERCENT       25
-#define DM_BUFIO_WRITEBACK_PERCENT     75
+#define DM_BUFIO_WRITEBACK_RATIO       3
 
 /*
  * Check buffer ages in this interval (seconds)
@@ -211,11 +211,6 @@ static unsigned long dm_bufio_current_allocated;
 
 /*----------------------------------------------------------------*/
 
-/*
- * Per-client cache: dm_bufio_cache_size / dm_bufio_client_count
- */
-static unsigned long dm_bufio_cache_size_per_client;
-
 /*
  * The current number of clients.
  */
@@ -227,8 +222,7 @@ static int dm_bufio_client_count;
 static LIST_HEAD(dm_bufio_all_clients);
 
 /*
- * This mutex protects dm_bufio_cache_size_latch,
- * dm_bufio_cache_size_per_client and dm_bufio_client_count
+ * This mutex protects dm_bufio_cache_size_latch and dm_bufio_client_count
  */
 static DEFINE_MUTEX(dm_bufio_clients_lock);
 
@@ -340,9 +334,6 @@ static void __cache_size_refresh(void)
                              dm_bufio_default_cache_size);
                dm_bufio_cache_size_latch = dm_bufio_default_cache_size;
        }
-
-       dm_bufio_cache_size_per_client = dm_bufio_cache_size_latch /
-                                        (dm_bufio_client_count ? : 1);
 }
 
 /*
@@ -923,36 +914,6 @@ static void __write_dirty_buffers_async(struct dm_bufio_client *c, int no_wait,
        }
 }
 
-/*
- * Get writeback threshold and buffer limit for a given client.
- */
-static void __get_memory_limit(struct dm_bufio_client *c,
-                              unsigned long *threshold_buffers,
-                              unsigned long *limit_buffers)
-{
-       unsigned long buffers;
-
-       if (unlikely(READ_ONCE(dm_bufio_cache_size) != dm_bufio_cache_size_latch)) {
-               if (mutex_trylock(&dm_bufio_clients_lock)) {
-                       __cache_size_refresh();
-                       mutex_unlock(&dm_bufio_clients_lock);
-               }
-       }
-
-       buffers = dm_bufio_cache_size_per_client;
-       if (likely(c->sectors_per_block_bits >= 0))
-               buffers >>= c->sectors_per_block_bits + SECTOR_SHIFT;
-       else
-               buffers /= c->block_size;
-
-       if (buffers < c->minimum_buffers)
-               buffers = c->minimum_buffers;
-
-       *limit_buffers = buffers;
-       *threshold_buffers = mult_frac(buffers,
-                                      DM_BUFIO_WRITEBACK_PERCENT, 100);
-}
-
 /*
  * Check if we're over watermark.
  * If we are over threshold_buffers, start freeing buffers.
@@ -961,23 +922,7 @@ static void __get_memory_limit(struct dm_bufio_client *c,
 static void __check_watermark(struct dm_bufio_client *c,
                              struct list_head *write_list)
 {
-       unsigned long threshold_buffers, limit_buffers;
-
-       __get_memory_limit(c, &threshold_buffers, &limit_buffers);
-
-       while (c->n_buffers[LIST_CLEAN] + c->n_buffers[LIST_DIRTY] >
-              limit_buffers) {
-
-               struct dm_buffer *b = __get_unclaimed_buffer(c);
-
-               if (!b)
-                       return;
-
-               __free_buffer_wake(b);
-               cond_resched();
-       }
-
-       if (c->n_buffers[LIST_DIRTY] > threshold_buffers)
+       if (c->n_buffers[LIST_DIRTY] > c->n_buffers[LIST_CLEAN] * DM_BUFIO_WRITEBACK_RATIO)
                __write_dirty_buffers_async(c, 1, write_list);
 }