Gu Zheng <guz.f...@cn.fujitsu.com> writes: > Previously, we only offer a single iovec to handle all the read/write cases, > so > the PREADV/PWRITEV request always need to alloc more iovec buffer when copying > user vectors. > If we use a tmp iovec array rather than the single one, some small > PREADV/PWRITEV > workloads(vector size small than the tmp buffer) will not need to alloc more > iovec buffer when copying user vectors.
Hi, Gu, This still doesn't explain why you decided to look into this. Did you notice a performance issue in this path? Do you have benchmarks that show some speedup due to this change? Thanks, Jeff > > Reviewed-by: Jeff Moyer <jmo...@redhat.com> > Signed-off-by: Gu Zheng <guz.f...@cn.fujitsu.com> > --- > fs/aio.c | 10 +++++----- > 1 files changed, 5 insertions(+), 5 deletions(-) > > diff --git a/fs/aio.c b/fs/aio.c > index f1fede2..df3491a 100644 > --- a/fs/aio.c > +++ b/fs/aio.c > @@ -1267,12 +1267,12 @@ static ssize_t aio_setup_vectored_rw(struct kiocb > *kiocb, > if (compat) > ret = compat_rw_copy_check_uvector(rw, > (struct compat_iovec __user *)buf, > - *nr_segs, 1, *iovec, iovec); > + *nr_segs, UIO_FASTIOV, *iovec, iovec); > else > #endif > ret = rw_copy_check_uvector(rw, > (struct iovec __user *)buf, > - *nr_segs, 1, *iovec, iovec); > + *nr_segs, UIO_FASTIOV, *iovec, iovec); > if (ret < 0) > return ret; > > @@ -1309,7 +1309,7 @@ static ssize_t aio_run_iocb(struct kiocb *req, unsigned > opcode, > fmode_t mode; > aio_rw_op *rw_op; > rw_iter_op *iter_op; > - struct iovec inline_vec, *iovec = &inline_vec; > + struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs; > struct iov_iter iter; > > switch (opcode) { > @@ -1344,7 +1344,7 @@ rw_common: > if (!ret) > ret = rw_verify_area(rw, file, &req->ki_pos, > req->ki_nbytes); > if (ret < 0) { > - if (iovec != &inline_vec) > + if (iovec != inline_vecs) > kfree(iovec); > return ret; > } > @@ -1391,7 +1391,7 @@ rw_common: > return -EINVAL; > } > > - if (iovec != &inline_vec) > + if (iovec != inline_vecs) > kfree(iovec); > > if (ret != -EIOCBQUEUED) { -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/