* Re: [RESEND PATCH 4/4] aio: use iovec array rather than the single one
[not found] ` <1406109834-4414-4-git-send-email-guz.fnst@cn.fujitsu.com>
@ 2014-07-23 13:25 ` Jeff Moyer
2014-07-24 1:15 ` Gu Zheng
2014-07-24 15:56 ` Benjamin LaHaise
1 sibling, 1 reply; 6+ messages in thread
From: Jeff Moyer @ 2014-07-23 13:25 UTC (permalink / raw)
To: Gu Zheng; +Cc: bcrl, axboe, akpm, linux-aio, linux-kernel
Gu Zheng <guz.fnst@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 <jmoyer@redhat.com>
> Signed-off-by: Gu Zheng <guz.fnst@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) {
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [RESEND PATCH 4/4] aio: use iovec array rather than the single one
2014-07-23 13:25 ` [RESEND PATCH 4/4] aio: use iovec array rather than the single one Jeff Moyer
@ 2014-07-24 1:15 ` Gu Zheng
0 siblings, 0 replies; 6+ messages in thread
From: Gu Zheng @ 2014-07-24 1:15 UTC (permalink / raw)
To: Jeff Moyer; +Cc: bcrl, axboe, akpm, linux-aio, linux-kernel
Hi Jeff,
On 07/23/2014 09:25 PM, Jeff Moyer wrote:
> Gu Zheng <guz.fnst@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.
The comment is clear, just want to avoid some needless memory allocation in
the io submit path.
> Did you
> notice a performance issue in this path? Do you have benchmarks that
> show some speedup due to this change?
Just some common tests based on fio, it gains a slight improvement(~3%) when the
iodepth in [5,6,7] than before. I did not paste these info here, because I think
other guys(especially the guys have production environment) who are interested
in this can give us more meaningful feedback.
Thanks,
Gu
>
> Thanks,
> Jeff
>
>>
>> Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
>> Signed-off-by: Gu Zheng <guz.fnst@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) {
> .
>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [RESEND PATCH 1/4] aio: remove the needless registration of ring file's private_data
[not found] <1406109834-4414-1-git-send-email-guz.fnst@cn.fujitsu.com>
[not found] ` <1406109834-4414-4-git-send-email-guz.fnst@cn.fujitsu.com>
@ 2014-07-24 15:55 ` Benjamin LaHaise
[not found] ` <1406109834-4414-2-git-send-email-guz.fnst@cn.fujitsu.com>
[not found] ` <1406109834-4414-3-git-send-email-guz.fnst@cn.fujitsu.com>
3 siblings, 0 replies; 6+ messages in thread
From: Benjamin LaHaise @ 2014-07-24 15:55 UTC (permalink / raw)
To: Gu Zheng; +Cc: axboe, akpm, jmoyer, linux-aio, linux-kernel
On Wed, Jul 23, 2014 at 06:03:51PM +0800, Gu Zheng wrote:
> Remove the registration of ring file's private_data, we do not use
> it.
Thanks Gu -- applied to my aio-next tree at
git://git.kvack.org/~bcrl/aio-next.git .
-ben
> Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
> Signed-off-by: Gu Zheng <guz.fnst@cn.fujitsu.com>
> ---
> fs/aio.c | 1 -
> 1 files changed, 0 insertions(+), 1 deletions(-)
>
> diff --git a/fs/aio.c b/fs/aio.c
> index 1c9c5f0..94546ab 100644
> --- a/fs/aio.c
> +++ b/fs/aio.c
> @@ -192,7 +192,6 @@ static struct file *aio_private_file(struct kioctx *ctx, loff_t nr_pages)
> }
>
> file->f_flags = O_RDWR;
> - file->private_data = ctx;
> return file;
> }
>
> --
> 1.7.7
--
"Thought is the essence of where you are now."
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [RESEND PATCH 2/4] aio: use the macro rather than the inline magic number
[not found] ` <1406109834-4414-2-git-send-email-guz.fnst@cn.fujitsu.com>
@ 2014-07-24 15:55 ` Benjamin LaHaise
0 siblings, 0 replies; 6+ messages in thread
From: Benjamin LaHaise @ 2014-07-24 15:55 UTC (permalink / raw)
To: Gu Zheng; +Cc: axboe, akpm, jmoyer, linux-aio, linux-kernel
On Wed, Jul 23, 2014 at 06:03:52PM +0800, Gu Zheng wrote:
> Replace the inline magic number with the ready-made macro(AIO_RING_MAGIC),
> just clean up.
Thanks Gu -- applied to my aio-next tree at
git://git.kvack.org/~bcrl/aio-next.git .
-ben
> Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
> Signed-off-by: Gu Zheng <guz.fnst@cn.fujitsu.com>
> ---
> fs/aio.c | 2 +-
> 1 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/fs/aio.c b/fs/aio.c
> index 94546ab..e0f838d 100644
> --- a/fs/aio.c
> +++ b/fs/aio.c
> @@ -201,7 +201,7 @@ static struct dentry *aio_mount(struct file_system_type *fs_type,
> static const struct dentry_operations ops = {
> .d_dname = simple_dname,
> };
> - return mount_pseudo(fs_type, "aio:", NULL, &ops, 0xa10a10a1);
> + return mount_pseudo(fs_type, "aio:", NULL, &ops, AIO_RING_MAGIC);
> }
>
> /* aio_setup
> --
> 1.7.7
--
"Thought is the essence of where you are now."
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [RESEND PATCH 3/4] aio: fix some comments
[not found] ` <1406109834-4414-3-git-send-email-guz.fnst@cn.fujitsu.com>
@ 2014-07-24 15:56 ` Benjamin LaHaise
0 siblings, 0 replies; 6+ messages in thread
From: Benjamin LaHaise @ 2014-07-24 15:56 UTC (permalink / raw)
To: Gu Zheng; +Cc: axboe, akpm, jmoyer, linux-aio, linux-kernel
On Wed, Jul 23, 2014 at 06:03:53PM +0800, Gu Zheng wrote:
> The function comments of aio_run_iocb and aio_read_events are out of date, so
> fix them here.
Thanks Gu -- applied to my aio-next tree at
git://git.kvack.org/~bcrl/aio-next.git .
-ben
> Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
> Signed-off-by: Gu Zheng <guz.fnst@cn.fujitsu.com>
> ---
> fs/aio.c | 7 +++----
> 1 files changed, 3 insertions(+), 4 deletions(-)
>
> diff --git a/fs/aio.c b/fs/aio.c
> index e0f838d..f1fede2 100644
> --- a/fs/aio.c
> +++ b/fs/aio.c
> @@ -1044,7 +1044,7 @@ void aio_complete(struct kiocb *iocb, long res, long res2)
> }
> EXPORT_SYMBOL(aio_complete);
>
> -/* aio_read_events
> +/* aio_read_events_ring
> * Pull an event off of the ioctx's event ring. Returns the number of
> * events fetched
> */
> @@ -1296,9 +1296,8 @@ static ssize_t aio_setup_single_vector(struct kiocb *kiocb,
> }
>
> /*
> - * aio_setup_iocb:
> - * Performs the initial checks and aio retry method
> - * setup for the kiocb at the time of io submission.
> + * aio_run_iocb:
> + * Performs the initial checks and io submission.
> */
> static ssize_t aio_run_iocb(struct kiocb *req, unsigned opcode,
> char __user *buf, bool compat)
> --
> 1.7.7
--
"Thought is the essence of where you are now."
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [RESEND PATCH 4/4] aio: use iovec array rather than the single one
[not found] ` <1406109834-4414-4-git-send-email-guz.fnst@cn.fujitsu.com>
2014-07-23 13:25 ` [RESEND PATCH 4/4] aio: use iovec array rather than the single one Jeff Moyer
@ 2014-07-24 15:56 ` Benjamin LaHaise
1 sibling, 0 replies; 6+ messages in thread
From: Benjamin LaHaise @ 2014-07-24 15:56 UTC (permalink / raw)
To: Gu Zheng; +Cc: axboe, akpm, jmoyer, linux-aio, linux-kernel
On Wed, Jul 23, 2014 at 06:03:54PM +0800, Gu Zheng wrote:
> 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.
Thanks Gu -- applied to my aio-next tree at
git://git.kvack.org/~bcrl/aio-next.git .
-ben
> Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
> Signed-off-by: Gu Zheng <guz.fnst@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) {
> --
> 1.7.7
--
"Thought is the essence of where you are now."
^ permalink raw reply [flat|nested] 6+ messages in thread
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2014-07-23 13:25 ` [RESEND PATCH 4/4] aio: use iovec array rather than the single one Jeff Moyer
2014-07-24 1:15 ` Gu Zheng
2014-07-24 15:56 ` Benjamin LaHaise
2014-07-24 15:55 ` [RESEND PATCH 1/4] aio: remove the needless registration of ring file's private_data Benjamin LaHaise
[not found] ` <1406109834-4414-2-git-send-email-guz.fnst@cn.fujitsu.com>
2014-07-24 15:55 ` [RESEND PATCH 2/4] aio: use the macro rather than the inline magic number Benjamin LaHaise
[not found] ` <1406109834-4414-3-git-send-email-guz.fnst@cn.fujitsu.com>
2014-07-24 15:56 ` [RESEND PATCH 3/4] aio: fix some comments Benjamin LaHaise
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