Limit the number of blocks to discard at once.

[zfs.git] / module / zfs / zvol.c

diff --git a/module/zfs/zvol.c b/module/zfs/zvol.c
index 125d58d..32e4f3c 100644 (file)
--- a/module/zfs/zvol.c
+++ b/module/zfs/zvol.c
@@ -49,6 +49,7 @@
 unsigned int zvol_inhibit_dev = 0;
 unsigned int zvol_major = ZVOL_MAJOR;
 unsigned int zvol_threads = 32;
+unsigned long zvol_max_discard_blocks = 16384;
 
 static taskq_t *zvol_taskq;
 static kmutex_t zvol_state_lock;
@@ -1242,7 +1243,8 @@ __zvol_create_minor(const char *name)
        blk_queue_physical_block_size(zv->zv_queue, zv->zv_volblocksize);
        blk_queue_io_opt(zv->zv_queue, zv->zv_volblocksize);
 #ifdef HAVE_BLK_QUEUE_DISCARD
-       blk_queue_max_discard_sectors(zv->zv_queue, UINT_MAX);
+       blk_queue_max_discard_sectors(zv->zv_queue,
+           (zvol_max_discard_blocks * zv->zv_volblocksize) >> 9);
        queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, zv->zv_queue);
 #endif
 #ifdef HAVE_BLK_QUEUE_NONROT
@@ -1446,3 +1448,6 @@ MODULE_PARM_DESC(zvol_major, "Major number for zvol device");
 
 module_param(zvol_threads, uint, 0444);
 MODULE_PARM_DESC(zvol_threads, "Number of threads for zvol device");
+
+module_param(zvol_max_discard_blocks, ulong, 0444);
+MODULE_PARM_DESC(zvol_max_discard_blocks, "Max number of blocks to discard at once");