On 8/28/16 10:12 PM, Qu Wenruo wrote: > > > At 08/29/2016 10:11 AM, Qu Wenruo wrote: >> >> >> At 08/28/2016 11:38 AM, Oliver Freyermuth wrote: >>> Dear btrfs experts, >>> >>> I just tried to make use of btrfs send / receive for incremental >>> backups (using btrbk to simplify the process). >>> It seems that on my two machines, btrfs send gets stuck after >>> transferring some GiB - it's not fully halted, but instead of making >>> full use of the available I/O, I get something < 500 kiB on average, >>> which are just some "full speed spikes" with many seconds / minutes of >>> no I/O in between. >>> >>> During this "halting", btrfs send eats one full CPU core. >>> A "perf top" shows this is spent in "find_parent_nodes" and >>> "__merge_refs" inside the kernel. >>> I am using btrfs-progs 4.7 and kernel 4.7.0. >> >> Unknown bug, while unfortunately no good idea to solve yet. > > Sorry, known bug, not unknown....
I'm working on a patch to replace the lists with a pair of trees that get merged after filling in the missing parents. The reflink xfstests don't complete, ever. btrfs/130 triggers soft lockups but do complete eventually -- and that's only with ~4k list elements. -Jeff -- Jeff Mahoney SUSE Labs
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