This patchset implements a new method of getting dmevents for multipathd. With the existing wait code, multipathd needs to create a waiter thread for every multipath device. This can become very wasteful in setups with large numbers of multipath devices. These duplicate threads all are serialized to update the multipath devices, so they don't actually speed up dmevent handling. The new method uses the new dmevent polling ability introduced in the 4.37.0 device-mapper kernel module. The original method has been retained for backwards compatablility, and it is possible to force multipathd to use the orignal method on newer kernels. The benefit of this new method is that there is only one thread necessary to wait on dmevents, which can be started when device-mapper starts, and stopped during shutdown, just like the other main threads. These patches use device-mapper features that don't have a libdevmapper API. They will switch over as soon as support is available in libdevmapper. This patchset is based on top of my recent "[PATCH v2 0/7] multipath: miscellaneous bug fixes". It doesn't touch the tur checker, so changes to "[PATCH v2 1/7] libmultipath: fix tur checker locking" won't change anything in this set. Benjamin Marzinski (5): libmultipath: move remove_map waiter code to multipathd move waiter code from libmultipath to multipathd call start_waiter_thread() before setup_multipath() libmultipath: add helper functions multipathd: RFC add new polling dmevents waiter thread libmultipath/Makefile | 2 +- libmultipath/devmapper.c | 28 +++- libmultipath/devmapper.h | 3 +- libmultipath/structs_vec.c | 138 +--------------- libmultipath/structs_vec.h | 6 +- libmultipath/vector.c | 16 +- libmultipath/vector.h | 1 + libmultipath/waiter.c | 215 ------------------------ libmultipath/waiter.h | 17 -- multipathd/Makefile | 3 +- multipathd/dmevents.c | 396 +++++++++++++++++++++++++++++++++++++++++++++ multipathd/dmevents.h | 13 ++ multipathd/main.c | 194 ++++++++++++++++++++-- multipathd/waiter.c | 215 ++++++++++++++++++++++++ multipathd/waiter.h | 17 ++ 15 files changed, 869 insertions(+), 395 deletions(-) delete mode 100644 libmultipath/waiter.c delete mode 100644 libmultipath/waiter.h create mode 100644 multipathd/dmevents.c create mode 100644 multipathd/dmevents.h create mode 100644 multipathd/waiter.c create mode 100644 multipathd/waiter.h -- 2.7.4 -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
