Re: [PATCH v1] vhost: avoid large order allocations

"Michael S. Tsirkin" [off-list ref] writes:

Please dont' do this, extra indirection hurts performance.
Instead, please change vhost_net_open and scsi to allocate the whole
structure with vmalloc if kmalloc fails, along the lines of
74d332c13b2148ae934ea94dac1745ae92efe8e5

Back in January 2013, you didn't seem to think it was a good idea:

https://lkml.org/lkml/2013/1/23/492

On Tue, 13 May 2014 16:29:58 +0200
Romain Francoise [off-list ref] wrote:

"Michael S. Tsirkin" [off-list ref] writes:

quoted

Please dont' do this, extra indirection hurts performance.
Instead, please change vhost_net_open and scsi to allocate the whole
structure with vmalloc if kmalloc fails, along the lines of
74d332c13b2148ae934ea94dac1745ae92efe8e5

Back in January 2013, you didn't seem to think it was a good idea:

https://lkml.org/lkml/2013/1/23/492

Hi Romain,

in that case I'd suggest that you submit your patch, ours will look pretty much the same!

Cheers
Michael

On Tue, May 13, 2014 at 04:29:58PM +0200, Romain Francoise wrote:

"Michael S. Tsirkin" [off-list ref] writes:

quoted

Please dont' do this, extra indirection hurts performance.
Instead, please change vhost_net_open and scsi to allocate the whole
structure with vmalloc if kmalloc fails, along the lines of
74d332c13b2148ae934ea94dac1745ae92efe8e5

Back in January 2013, you didn't seem to think it was a good idea:

https://lkml.org/lkml/2013/1/23/492

Hmm true, and Dave thought the structure's too large.
I'll have to do some benchmarks to see what the effect
of Michael's patch is, performance-wise.
If it's too expensive I can pick up your patch, no need to
repost.

-- 
MST

On Tue, 13 May 2014 18:15:27 +0300
"Michael S. Tsirkin" [off-list ref] wrote:

On Tue, May 13, 2014 at 04:29:58PM +0200, Romain Francoise wrote:

quoted

"Michael S. Tsirkin" [off-list ref] writes:

quoted

Please dont' do this, extra indirection hurts performance.
Instead, please change vhost_net_open and scsi to allocate the whole
structure with vmalloc if kmalloc fails, along the lines of
74d332c13b2148ae934ea94dac1745ae92efe8e5

Back in January 2013, you didn't seem to think it was a good idea:

https://lkml.org/lkml/2013/1/23/492

Hmm true, and Dave thought the structure's too large.
I'll have to do some benchmarks to see what the effect
of Michael's patch is, performance-wise.
If it's too expensive I can pick up your patch, no need to
repost.

Thanks, let us know then.

On Tue, 13 May 2014 18:15:27 +0300
"Michael S. Tsirkin" [off-list ref] wrote:

On Tue, May 13, 2014 at 04:29:58PM +0200, Romain Francoise wrote:

quoted

"Michael S. Tsirkin" [off-list ref] writes:

quoted

Please dont' do this, extra indirection hurts performance.
Instead, please change vhost_net_open and scsi to allocate the whole
structure with vmalloc if kmalloc fails, along the lines of
74d332c13b2148ae934ea94dac1745ae92efe8e5

Back in January 2013, you didn't seem to think it was a good idea:

https://lkml.org/lkml/2013/1/23/492

Hmm true, and Dave thought the structure's too large.
I'll have to do some benchmarks to see what the effect
of Michael's patch is, performance-wise.
If it's too expensive I can pick up your patch, no need to
repost.

Hi Michael,

do you have any update in this case for us?

Michael