Hi I placed the new code using srcu here: http://people.redhat.com/mpatocka/patches/kernel/dm-lock-optimization/ It removes io_lock, map_lock and holders and replaces them with srcu. On Mon, 23 Apr 2012, Jun'ichi Nomura wrote: > Hi Mikulas, > > On 04/22/12 01:17, Mikulas Patocka wrote: > > I created new patches that use rcu instead of map_lock, so they address > > the issues you mentioned. Get the new patches here: > > http://people.redhat.com/mpatocka/patches/kernel/dm-lock-optimization/ > > > > performance with new patches: > > no patch: 69.3 > > patch 1: 54.0 > > patch 1,2: 44.2 > > patch 1,2,3: 39.8 > > patch 1,2,3,4: 32.7 > > Thank you. I have 2 comments for the new patches. > > synchronize_rcu could be put in dm_table_destroy() instead of __bind(). > I think it's safer place to wait. I think the code is more readable if synchronizing rcu is just after assigning the pointer that is protected by rcu. > io_lock could be converted to SRCU. > I.e. something like: > On reader-side: > idx = srcu_read_lock(io_srcu); > if (!DMF_BLOCK_IO_FOR_SUSPEND) > split_and_process_bio(); > srcu_read_unlock(io_srcu,idx); > In dm_suspend: > set_bit(DMF_BLOCK_IO_FOR_SUSPEND); > mb(); > synchronize_srcu(io_srcu); > <from here, nobody will enter split_and_process_bio> > That makes dm-optimize-percpu-io-lock.patch simpler. > dm-optimize-take-io_lock-on-table-swap.patch may become simpler, too. > > -- > Jun'ichi Nomura, NEC Corporation Mikulas -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
