Recently, there was a dicussion about removing rw_page due to maintainance burden[1] but the problem was zram because zram has a clear win for the benchmark at that time. The reason why only zram have a win is due to bio allocation wait time from mempool under extreme memory pressure.
Christoph Hellwig suggested we can use on-stack-bio for rw_page devices. This patch implements it and replace rw_page operations with on-stack-bio and then finally, remove rw_page interface completely. This patch is based on linux-next-20170804 [1] http://lkml.kernel.org/r/<20170728165604.10455-1-ross.zwis...@linux.intel.com> Minchan Kim (6): bdi: introduce BDI_CAP_SYNC fs: use on-stack-bio if backing device has BDI_CAP_SYNC capability mm:swap: remove end_swap_bio_write argument mm:swap: use on-stack-bio for BDI_CAP_SYNC devices zram: remove zram_rw_page fs: remove rw_page drivers/block/brd.c | 2 + drivers/block/zram/zram_drv.c | 54 +--------------- drivers/nvdimm/btt.c | 2 + drivers/nvdimm/pmem.c | 2 + fs/block_dev.c | 76 ---------------------- fs/mpage.c | 45 +++++++++++-- include/linux/backing-dev.h | 7 ++ include/linux/blkdev.h | 4 -- include/linux/swap.h | 6 +- mm/page_io.c | 145 +++++++++++++++++++++++++----------------- mm/swapfile.c | 3 + mm/zswap.c | 2 +- 12 files changed, 147 insertions(+), 201 deletions(-) -- 2.7.4
