Re: [PATCH vhost 2/2] vdpa/mlx5: Fix suboptimal range on iotlb iteration
On Wed, Nov 13, 2024 at 04:01:05PM +0100, Dragos Tatulea wrote:
>
>
> On 13.11.24 15:49, Michael S. Tsirkin wrote:
> > On Wed, Nov 13, 2024 at 03:33:35PM +0100, Dragos Tatulea wrote:
> >>
> >>
> >> On 13.11.24 07:32, Michael S. Tsirkin wrote:
> >>> On Mon, Oct 21, 2024 at 04:40:40PM +0300, Dragos Tatulea wrote:
> From: Si-Wei Liu
>
> The starting iova address to iterate iotlb map entry within a range
> was set to an irrelevant value when passing to the itree_next()
> iterator, although luckily it doesn't affect the outcome of finding
> out the granule of the smallest iotlb map size. Fix the code to make
> it consistent with the following for-loop.
>
> Fixes: 94abbccdf291 ("vdpa/mlx5: Add shared memory registration code")
> >>>
> >>>
> >>> But the cover letter says "that's why it does not have a fixes tag".
> >>> Confused.
> >> Sorry about that. Patch is fine with fixes tag, I forgot to drop that
> >> part of the sentence from the cover letter.
> >>
> >> Let me know if I need to resend something.
> >>
> >> Thanks,
> >> Dragos
> >
> > But why does it need the fixes tag? That one means "if you have
> > that hash, you need this patch". Pls do not abuse it for
> > optimizations.
> >
> Well, it is a fix but it happens that the code around still works without
> this fix. I figured that it would be better to take it into older stable
> kernels
> just like the other one. But if you consider it an improvement I will send a
> v2
> without the Fixes tag.
>
> Thanks,
> Dragos
No need.
Re: [PATCH vhost 2/2] vdpa/mlx5: Fix suboptimal range on iotlb iteration
On 13.11.24 15:49, Michael S. Tsirkin wrote:
> On Wed, Nov 13, 2024 at 03:33:35PM +0100, Dragos Tatulea wrote:
>>
>>
>> On 13.11.24 07:32, Michael S. Tsirkin wrote:
>>> On Mon, Oct 21, 2024 at 04:40:40PM +0300, Dragos Tatulea wrote:
From: Si-Wei Liu
The starting iova address to iterate iotlb map entry within a range
was set to an irrelevant value when passing to the itree_next()
iterator, although luckily it doesn't affect the outcome of finding
out the granule of the smallest iotlb map size. Fix the code to make
it consistent with the following for-loop.
Fixes: 94abbccdf291 ("vdpa/mlx5: Add shared memory registration code")
>>>
>>>
>>> But the cover letter says "that's why it does not have a fixes tag".
>>> Confused.
>> Sorry about that. Patch is fine with fixes tag, I forgot to drop that
>> part of the sentence from the cover letter.
>>
>> Let me know if I need to resend something.
>>
>> Thanks,
>> Dragos
>
> But why does it need the fixes tag? That one means "if you have
> that hash, you need this patch". Pls do not abuse it for
> optimizations.
>
Well, it is a fix but it happens that the code around still works without
this fix. I figured that it would be better to take it into older stable kernels
just like the other one. But if you consider it an improvement I will send a v2
without the Fixes tag.
Thanks,
Dragos
Re: [PATCH vhost 2/2] vdpa/mlx5: Fix suboptimal range on iotlb iteration
On Wed, Nov 13, 2024 at 03:33:35PM +0100, Dragos Tatulea wrote:
>
>
> On 13.11.24 07:32, Michael S. Tsirkin wrote:
> > On Mon, Oct 21, 2024 at 04:40:40PM +0300, Dragos Tatulea wrote:
> >> From: Si-Wei Liu
> >>
> >> The starting iova address to iterate iotlb map entry within a range
> >> was set to an irrelevant value when passing to the itree_next()
> >> iterator, although luckily it doesn't affect the outcome of finding
> >> out the granule of the smallest iotlb map size. Fix the code to make
> >> it consistent with the following for-loop.
> >>
> >> Fixes: 94abbccdf291 ("vdpa/mlx5: Add shared memory registration code")
> >
> >
> > But the cover letter says "that's why it does not have a fixes tag".
> > Confused.
> Sorry about that. Patch is fine with fixes tag, I forgot to drop that
> part of the sentence from the cover letter.
>
> Let me know if I need to resend something.
>
> Thanks,
> Dragos
But why does it need the fixes tag? That one means "if you have
that hash, you need this patch". Pls do not abuse it for
optimizations.
Re: [PATCH vhost 2/2] vdpa/mlx5: Fix suboptimal range on iotlb iteration
On 13.11.24 07:32, Michael S. Tsirkin wrote:
> On Mon, Oct 21, 2024 at 04:40:40PM +0300, Dragos Tatulea wrote:
>> From: Si-Wei Liu
>>
>> The starting iova address to iterate iotlb map entry within a range
>> was set to an irrelevant value when passing to the itree_next()
>> iterator, although luckily it doesn't affect the outcome of finding
>> out the granule of the smallest iotlb map size. Fix the code to make
>> it consistent with the following for-loop.
>>
>> Fixes: 94abbccdf291 ("vdpa/mlx5: Add shared memory registration code")
>
>
> But the cover letter says "that's why it does not have a fixes tag".
> Confused.
Sorry about that. Patch is fine with fixes tag, I forgot to drop that
part of the sentence from the cover letter.
Let me know if I need to resend something.
Thanks,
Dragos
Re: [PATCH vhost 2/2] vdpa/mlx5: Fix suboptimal range on iotlb iteration
On Mon, Oct 21, 2024 at 04:40:40PM +0300, Dragos Tatulea wrote:
> From: Si-Wei Liu
>
> The starting iova address to iterate iotlb map entry within a range
> was set to an irrelevant value when passing to the itree_next()
> iterator, although luckily it doesn't affect the outcome of finding
> out the granule of the smallest iotlb map size. Fix the code to make
> it consistent with the following for-loop.
>
> Fixes: 94abbccdf291 ("vdpa/mlx5: Add shared memory registration code")
But the cover letter says "that's why it does not have a fixes tag".
Confused.
> Signed-off-by: Si-Wei Liu
> Signed-off-by: Dragos Tatulea
> ---
> drivers/vdpa/mlx5/core/mr.c | 4 +---
> 1 file changed, 1 insertion(+), 3 deletions(-)
>
> diff --git a/drivers/vdpa/mlx5/core/mr.c b/drivers/vdpa/mlx5/core/mr.c
> index 7d0c83b5b071..8455f08f5d40 100644
> --- a/drivers/vdpa/mlx5/core/mr.c
> +++ b/drivers/vdpa/mlx5/core/mr.c
> @@ -368,7 +368,6 @@ static int map_direct_mr(struct mlx5_vdpa_dev *mvdev,
> struct mlx5_vdpa_direct_mr
> unsigned long lgcd = 0;
> int log_entity_size;
> unsigned long size;
> - u64 start = 0;
> int err;
> struct page *pg;
> unsigned int nsg;
> @@ -379,10 +378,9 @@ static int map_direct_mr(struct mlx5_vdpa_dev *mvdev,
> struct mlx5_vdpa_direct_mr
> struct device *dma = mvdev->vdev.dma_dev;
>
> for (map = vhost_iotlb_itree_first(iotlb, mr->start, mr->end - 1);
> - map; map = vhost_iotlb_itree_next(map, start, mr->end - 1)) {
> + map; map = vhost_iotlb_itree_next(map, mr->start, mr->end - 1)) {
> size = maplen(map, mr);
> lgcd = gcd(lgcd, size);
> - start += size;
> }
> log_entity_size = ilog2(lgcd);
>
> --
> 2.46.1
Re: [PATCH vhost 2/2] vdpa/mlx5: Fix suboptimal range on iotlb iteration
On Mon, Oct 21, 2024 at 9:41 PM Dragos Tatulea wrote:
>
> From: Si-Wei Liu
>
> The starting iova address to iterate iotlb map entry within a range
> was set to an irrelevant value when passing to the itree_next()
> iterator, although luckily it doesn't affect the outcome of finding
> out the granule of the smallest iotlb map size. Fix the code to make
> it consistent with the following for-loop.
>
> Fixes: 94abbccdf291 ("vdpa/mlx5: Add shared memory registration code")
> Signed-off-by: Si-Wei Liu
> Signed-off-by: Dragos Tatulea
> ---
Acked-by: Jason Wang
Thanks
