On Tue, Aug 27, 2019 at 10:05:49AM +0800, Joseph Qi wrote: > This patch set is trying to revert parallel dio reads feature at present > since it causes significant performance regression in mixed random > read/write scenario. > > Joseph Qi (3): > Revert "ext4: remove EXT4_STATE_DIOREAD_LOCK flag" > Revert "ext4: fix off-by-one error when writing back pages before dio > read" > Revert "ext4: Allow parallel DIO reads" > > fs/ext4/ext4.h | 17 +++++++++++++++++ > fs/ext4/extents.c | 19 ++++++++++++++----- > fs/ext4/inode.c | 47 +++++++++++++++++++++++++++++++---------------- > fs/ext4/ioctl.c | 4 ++++ > fs/ext4/move_extent.c | 4 ++++ > fs/ext4/super.c | 12 +++++++----- > 6 files changed, 77 insertions(+), 26 deletions(-) Before doing this, you might want to have a chat and co-ordinate with the folks that are currently trying to port the ext4 direct IO code to use the iomap infrastructure: https://lore.kernel.org/linux-ext4/20190827095221.GA1568@xxxxxxxxxxxxxxxxxxxxxx/T/#t That is going to need the shared locking on read and will work just fine with shared locking on write, too (it's the code that XFS uses for direct IO). So it might be best here if you work towards shared locking on the write side rather than just revert the shared locking on the read side.... Cheers, Dave, -- Dave Chinner david@xxxxxxxxxxxxx
