Hi Jeff, On 07/22/2014 11:20 PM, Jeff Moyer wrote: > Gu Zheng <guz.f...@cn.fujitsu.com> writes: > >> use an iovec array rather than the single one, so that we can avoid >> to alloc more iovecs buffer in small(< 8) PREADV/PWRITEV cases. > > I did some basic functional testing of this change and the change in > patch 1/4. That testing included using aio-stress to drive queue depths > of 7, 8 and 9, and verify that it didn't fall over. I also ran xfstests > './check -g aio', and libaio's 'make partcheck'.
> > The change looks good to me, and passed testing, so: > > Reviewed-by: Jeff Moyer <jmo...@redhat.com> Thanks for your review and test. > > However, I still would like some comment on the reasoning behind it, and > whether there is some measurable performance advantage for some > workload. Additionally, it would be nice if that comment made its way > into the commit message. I'll add more useful info, and send it out later. Thanks, Gu > > Cheers, > Jeff > >> >> 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 0cd0479..ef21efe 100644 >> --- a/fs/aio.c >> +++ b/fs/aio.c >> @@ -1260,12 +1260,12 @@ 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; >> >> @@ -1302,7 +1302,7 @@ 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) { >> @@ -1337,7 +1337,7 @@ 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; >> } >> @@ -1384,7 +1384,7 @@ 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/