Remove a code that cleans up buffers if the cache size grows over the limit.
The next patch will introduce a new global cleanup.
Signed-off-by: Mikulas Patocka <mpatocka@xxxxxxxxxx>
---
drivers/md/dm-bufio.c | 61 ++------------------------------------------------
1 file changed, 3 insertions(+), 58 deletions(-)
Index: linux-2.6/drivers/md/dm-bufio.c
===================================================================
--- linux-2.6.orig/drivers/md/dm-bufio.c 2019-09-10 17:34:24.000000000 +0200
+++ linux-2.6/drivers/md/dm-bufio.c 2019-09-10 17:34:29.000000000 +0200
@@ -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)
@@ -213,11 +213,6 @@ static unsigned long dm_bufio_current_al
/*----------------------------------------------------------------*/
/*
- * 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.
*/
static int dm_bufio_client_count;
@@ -228,8 +223,7 @@ 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);
@@ -341,9 +335,6 @@ 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);
}
/*
@@ -927,36 +918,6 @@ static void __write_dirty_buffers_async(
}
/*
- * 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.
* If we're over "limit_buffers", block until we get under the limit.
@@ -964,23 +925,7 @@ static void __get_memory_limit(struct dm
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);
}
--
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