ping again. >From my test, the patchset can improve the performance significantly. The following data are tested on INTEL P4510 NVMe using fio with iodepth 128 and blocksize 4k. ---------------------------------------------------------------- | RANDREAD | RANDWRITE | ---------------------------------------------------------------- w/ async IO routines | 377MB/s | 405MB/s | ---------------------------------------------------------------- w/o async IO routines | 32.0MB/s | 62.3MB/s | ---------------------------------------------------------------- Regards, Jiufei On 2019/11/26 上午10:00, Jiufei Xue wrote: > Hi miklos, > > Could you please kindly review this patch and give some advice? > > Thanks, > Jiufei > > On 2019/11/20 下午5:45, Jiufei Xue wrote: >> ovl stacks regular file operations now. However it doesn't implement >> async IO routines and will convert async IOs to sync IOs which is not >> expected. >> >> This patchset implements overlayfs async IO routines. >> >> Jiufei Xue (2) >> vfs: add vfs_iocb_iter_[read|write] helper functions >> ovl: implement async IO routines >> >> fs/overlayfs/file.c | 116 +++++++++++++++++++++++++++++++++++++++++------ >> fs/overlayfs/overlayfs.h | 2 >> fs/overlayfs/super.c | 12 ++++ >> fs/read_write.c | 58 +++++++++++++++++++++++ >> include/linux/fs.h | 16 ++++++ >> 5 files changed, 188 insertions(+), 16 deletions(-) >> >