Hi Jens Please would you consider taking this into the block tree? It seems to speed up device deletion enormously. Mikulas --- backing-dev: use synchronize_rcu_expedited instead of synchronize_rcu synchronize_rcu sleeps several timer ticks. synchronize_rcu_expedited is much faster. With 100Hz timer frequency, when we remove 10000 block devices with "dmsetup remove_all" command, it takes 27 minutes. With this patch, removing 10000 block devices takes only 15 seconds. Signed-off-by: Mikulas Patocka <mpatocka@xxxxxxxxxx> --- mm/backing-dev.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) Index: linux-3.0-rc7-fast/mm/backing-dev.c =================================================================== --- linux-3.0-rc7-fast.orig/mm/backing-dev.c 2011-07-19 18:01:00.000000000 +0200 +++ linux-3.0-rc7-fast/mm/backing-dev.c 2011-07-19 18:01:07.000000000 +0200 @@ -505,7 +505,7 @@ static void bdi_remove_from_list(struct list_del_rcu(&bdi->bdi_list); spin_unlock_bh(&bdi_lock); - synchronize_rcu(); + synchronize_rcu_expedited(); } int bdi_register(struct backing_dev_info *bdi, struct device *parent, -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
