[PATCH 0/4] md: use bio_clone_fast()

Ming Lei
2017-02-05T06:22:31Z

Hi,

This patches replaces bio_clone() with bio_fast_clone() in
bio_clone_mddev() because:

1) bio_clone_mddev() is used in raid normal I/O and isn't in
resync I/O path, and all the direct access to bvec table in
raid happens on resync I/O only except for write behind of raid1.
Write behind is treated specially, so the replacement is safe.

2) for write behind, bio_clone() is kept, but this patchset
introduces bio_clone_bioset_partial() to just clone one specific
bvecs range instead of whole table. Then write behind is improved
too.

Thanks,
Ming

Ming Lei (4):
block: introduce bio_clone_bioset_partial()
md: introduce bio_clone_slow_mddev_partial()
md/raid1: use bio_clone_slow_mddev_partial in case of write behind
md: fast clone bio in bio_clone_mddev()

block/bio.c | 61 +++++++++++++++++++++++++++++++++++++++++------------
drivers/md/md.c | 24 +++++++++++++++++++--
drivers/md/md.h | 3 +++
drivers/md/raid1.c | 21 +++++++++++++-----
include/linux/bio.h | 11 ++++++++--
5 files changed, 98 insertions(+), 22 deletions(-)

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2.7.4