[PATCH] Make swap accounting default behavior configurable

[PATCH] Make swap accounting default behavior configurable

[Michal Hocko]

Hi Andrew,
could you consider the following patch for the Linus tree, please?
The discussion took place in this email thread 
http://lkml.org/lkml/2010/11/10/114.
The patch is based on top of 151f52f09c572 commit in the Linus tree.

Please let me know if there I should route this patch through somebody
else.

Thanks!

---

Re: [PATCH] Make swap accounting default behavior configurable

[Andrew Morton]

On Tue, 16 Nov 2010 11:17:26 +0100
Michal Hocko <mhocko@suse.cz> wrote:

> Hi Andrew,
> could you consider the following patch for the Linus tree, please?
> The discussion took place in this email thread 
> http://lkml.org/lkml/2010/11/10/114.
> The patch is based on top of 151f52f09c572 commit in the Linus tree.
> 
> Please let me know if there I should route this patch through somebody
> else.
> 
> Thanks!
> 
> ---
> >From 30238aaec758988493af793939f14b0ba83dc4b3 Mon Sep 17 00:00:00 2001
> From: Michal Hocko <mhocko@suse.cz>
> Date: Wed, 10 Nov 2010 13:30:04 +0100
> Subject: [PATCH] Make swap accounting default behavior configurable
> 
> Swap accounting can be configured by CONFIG_CGROUP_MEM_RES_CTLR_SWAP
> configuration option and then it is turned on by default. There is
> a boot option (noswapaccount) which can disable this feature.
> 
> This makes it hard for distributors to enable the configuration option
> as this feature leads to a bigger memory consumption and this is a no-go
> for general purpose distribution kernel. On the other hand swap
> accounting may be very usuful for some workloads.

This patch is needed by distros, and distros use the -stable tree, I
assume.  Do you see reasons why this patch should be backported into
-stable, so distros don't need to patch it themselves?  If so, any
particular kernel versions?  2.6.37?

> This patch adds a new configuration option which controls the default
> behavior (CGROUP_MEM_RES_CTLR_SWAP_ENABLED). If the option is selected
> then the feature is turned on by default.
> 
> It also adds a new boot parameter swapaccount which (contrary to
> noswapaccount) enables the feature. (I would consider swapaccount=yes|no
> semantic with removed noswapaccount parameter much better but this
> parameter is kind of API which might be in use and unexpected breakage
> is no-go.)
> 
> The default behavior is unchanged (if CONFIG_CGROUP_MEM_RES_CTLR_SWAP is
> enabled then CONFIG_CGROUP_MEM_RES_CTLR_SWAP_ENABLED is enabled as well)
> 
> Signed-off-by: Michal Hocko <mhocko@suse.cz>
> Acked-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
> ---
>  Documentation/kernel-parameters.txt |    3 +++
>  init/Kconfig                        |   13 +++++++++++++
>  mm/memcontrol.c                     |   15 ++++++++++++++-
>  3 files changed, 30 insertions(+), 1 deletions(-)
> 
> diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
> index ed45e98..14eafa5 100644
> --- a/Documentation/kernel-parameters.txt
> +++ b/Documentation/kernel-parameters.txt
> @@ -2385,6 +2385,9 @@ and is between 256 and 4096 characters. It is defined in the file
>  			improve throughput, but will also increase the
>  			amount of memory reserved for use by the client.
>  
> +	swapaccount	[KNL] Enable accounting of swap in memory resource
> +			controller. (See Documentation/cgroups/memory.txt)

So we have swapaccount and noswapaccount.  Ho hum, "swapaccount=[1|0]"
would have been better.

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Re: [stable] [PATCH] Make swap accounting default behavior configurable

[Greg KH]

On Tue, Nov 16, 2010 at 12:46:15PM -0800, Andrew Morton wrote:
> On Tue, 16 Nov 2010 11:17:26 +0100
> Michal Hocko <mhocko@suse.cz> wrote:
> 
> > Hi Andrew,
> > could you consider the following patch for the Linus tree, please?
> > The discussion took place in this email thread 
> > http://lkml.org/lkml/2010/11/10/114.
> > The patch is based on top of 151f52f09c572 commit in the Linus tree.
> > 
> > Please let me know if there I should route this patch through somebody
> > else.
> > 
> > Thanks!
> > 
> > ---
> > >From 30238aaec758988493af793939f14b0ba83dc4b3 Mon Sep 17 00:00:00 2001
> > From: Michal Hocko <mhocko@suse.cz>
> > Date: Wed, 10 Nov 2010 13:30:04 +0100
> > Subject: [PATCH] Make swap accounting default behavior configurable
> > 
> > Swap accounting can be configured by CONFIG_CGROUP_MEM_RES_CTLR_SWAP
> > configuration option and then it is turned on by default. There is
> > a boot option (noswapaccount) which can disable this feature.
> > 
> > This makes it hard for distributors to enable the configuration option
> > as this feature leads to a bigger memory consumption and this is a no-go
> > for general purpose distribution kernel. On the other hand swap
> > accounting may be very usuful for some workloads.
> 
> This patch is needed by distros, and distros use the -stable tree, I
> assume.  Do you see reasons why this patch should be backported into
> -stable, so distros don't need to patch it themselves?  If so, any
> particular kernel versions?  2.6.37?

Sorry, I really don't want to start backporting features to stable
kernels if at all possible.  Distros can pick them up on their own if
they determine it is needed.

thanks,

greg k-h

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Re: [stable] [PATCH] Make swap accounting default behavior configurable

[Michal Hocko]

On Tue 16-11-10 13:21:57, Greg KH wrote:
> On Tue, Nov 16, 2010 at 12:46:15PM -0800, Andrew Morton wrote:
> > On Tue, 16 Nov 2010 11:17:26 +0100
> > Michal Hocko <mhocko@suse.cz> wrote:
> > 
> > > Hi Andrew,
> > > could you consider the following patch for the Linus tree, please?
> > > The discussion took place in this email thread 
> > > http://lkml.org/lkml/2010/11/10/114.
> > > The patch is based on top of 151f52f09c572 commit in the Linus tree.
> > > 
> > > Please let me know if there I should route this patch through somebody
> > > else.
> > > 
> > > Thanks!
> > > 
> > > ---
> > > >From 30238aaec758988493af793939f14b0ba83dc4b3 Mon Sep 17 00:00:00 2001
> > > From: Michal Hocko <mhocko@suse.cz>
> > > Date: Wed, 10 Nov 2010 13:30:04 +0100
> > > Subject: [PATCH] Make swap accounting default behavior configurable
> > > 
> > > Swap accounting can be configured by CONFIG_CGROUP_MEM_RES_CTLR_SWAP
> > > configuration option and then it is turned on by default. There is
> > > a boot option (noswapaccount) which can disable this feature.
> > > 
> > > This makes it hard for distributors to enable the configuration option
> > > as this feature leads to a bigger memory consumption and this is a no-go
> > > for general purpose distribution kernel. On the other hand swap
> > > accounting may be very usuful for some workloads.
> > 
> > This patch is needed by distros, and distros use the -stable tree, I
> > assume.  Do you see reasons why this patch should be backported into
> > -stable, so distros don't need to patch it themselves?  If so, any
> > particular kernel versions?  2.6.37?

I have suggested pushing to the stable in the original thread as well. 
I was told that this is not a bug fix.

I do not care much in which particular version to push this but I
guess this doesn't qualify as "regression fix only Linus policy" so it
is probably too late for .37.
Nevertheless, if we reconsider -stable then .37 would be much really
helpful to get it into stable ASAP.

> 
> Sorry, I really don't want to start backporting features to stable
> kernels if at all possible.  Distros can pick them up on their own if
> they determine it is needed.

I really do agree with the part about features. But isn't this patch
basically for distros (to help them to provide the swapaccounting feature
without the cost of higher memory consumption in default configuration)?
If this doesn't go to the stable then all (interested) of them would
need to maintain the patch. Otherwise the change would come directly
from the upstream.

Moreover, it is not a new feature it just consolidates the default
behavior of the already existing functionality.

> 
> thanks,
> 
> greg k-h

Thanks
-- 
Michal Hocko
L3 team 
SUSE LINUX s.r.o.
Lihovarska 1060/12
190 00 Praha 9    
Czech Republic

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Re: [stable] [PATCH] Make swap accounting default behavior configurable

[Greg KH]

On Thu, Nov 18, 2010 at 09:21:32AM +0100, Michal Hocko wrote:
> > Sorry, I really don't want to start backporting features to stable
> > kernels if at all possible.  Distros can pick them up on their own if
> > they determine it is needed.
> 
> I really do agree with the part about features. But isn't this patch
> basically for distros (to help them to provide the swapaccounting feature
> without the cost of higher memory consumption in default configuration)?

Then if the distros want it, they can pick it up themselves.

> If this doesn't go to the stable then all (interested) of them would
> need to maintain the patch. Otherwise the change would come directly
> from the upstream.

They can cherry-pick from upstream like they do for everything else, no
real change here.

> Moreover, it is not a new feature it just consolidates the default
> behavior of the already existing functionality.

Again, it doesn't match up with the stable kernel rules, sorry, no, this
is not a bugfix or regression.

thanks,

greg k-h

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Re: [PATCH] Make swap accounting default behavior configurable

[Daisuke Nishimura]

On Tue, 16 Nov 2010 12:46:15 -0800
Andrew Morton <akpm@linux-foundation.org> wrote:

> On Tue, 16 Nov 2010 11:17:26 +0100
> Michal Hocko <mhocko@suse.cz> wrote:
> 
> > Hi Andrew,
> > could you consider the following patch for the Linus tree, please?
> > The discussion took place in this email thread 
> > http://lkml.org/lkml/2010/11/10/114.
> > The patch is based on top of 151f52f09c572 commit in the Linus tree.
> > 
> > Please let me know if there I should route this patch through somebody
> > else.
> > 
> > Thanks!
> > 
> > ---
> > >From 30238aaec758988493af793939f14b0ba83dc4b3 Mon Sep 17 00:00:00 2001
> > From: Michal Hocko <mhocko@suse.cz>
> > Date: Wed, 10 Nov 2010 13:30:04 +0100
> > Subject: [PATCH] Make swap accounting default behavior configurable
> > 
> > Swap accounting can be configured by CONFIG_CGROUP_MEM_RES_CTLR_SWAP
> > configuration option and then it is turned on by default. There is
> > a boot option (noswapaccount) which can disable this feature.
> > 
> > This makes it hard for distributors to enable the configuration option
> > as this feature leads to a bigger memory consumption and this is a no-go
> > for general purpose distribution kernel. On the other hand swap
> > accounting may be very usuful for some workloads.
> 
> This patch is needed by distros, and distros use the -stable tree, I
> assume.  Do you see reasons why this patch should be backported into
> -stable, so distros don't need to patch it themselves?  If so, any
> particular kernel versions?  2.6.37?
> 
> > This patch adds a new configuration option which controls the default
> > behavior (CGROUP_MEM_RES_CTLR_SWAP_ENABLED). If the option is selected
> > then the feature is turned on by default.
> > 
> > It also adds a new boot parameter swapaccount which (contrary to
> > noswapaccount) enables the feature. (I would consider swapaccount=yes|no
> > semantic with removed noswapaccount parameter much better but this
> > parameter is kind of API which might be in use and unexpected breakage
> > is no-go.)
> > 
> > The default behavior is unchanged (if CONFIG_CGROUP_MEM_RES_CTLR_SWAP is
> > enabled then CONFIG_CGROUP_MEM_RES_CTLR_SWAP_ENABLED is enabled as well)
> > 
> > Signed-off-by: Michal Hocko <mhocko@suse.cz>
> > Acked-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
> > ---
> >  Documentation/kernel-parameters.txt |    3 +++
> >  init/Kconfig                        |   13 +++++++++++++
> >  mm/memcontrol.c                     |   15 ++++++++++++++-
> >  3 files changed, 30 insertions(+), 1 deletions(-)
> > 
> > diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
> > index ed45e98..14eafa5 100644
> > --- a/Documentation/kernel-parameters.txt
> > +++ b/Documentation/kernel-parameters.txt
> > @@ -2385,6 +2385,9 @@ and is between 256 and 4096 characters. It is defined in the file
> >  			improve throughput, but will also increase the
> >  			amount of memory reserved for use by the client.
> >  
> > +	swapaccount	[KNL] Enable accounting of swap in memory resource
> > +			controller. (See Documentation/cgroups/memory.txt)
> 
> So we have swapaccount and noswapaccount.  Ho hum, "swapaccount=[1|0]"
> would have been better.
> 
I suggested to keep "noswapaccount" for compatibility.
If you and other guys don't like having two parameters, I don't stick to
the old parameter.

Thanks,
Daisuke Nishimura.

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Re: [PATCH] Make swap accounting default behavior configurable

[KAMEZAWA Hiroyuki]

On Wed, 17 Nov 2010 09:23:39 +0900
Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> wrote:

> On Tue, 16 Nov 2010 12:46:15 -0800
> Andrew Morton <akpm@linux-foundation.org> wrote:
> 
> > On Tue, 16 Nov 2010 11:17:26 +0100
> > Michal Hocko <mhocko@suse.cz> wrote:
> > 
> > > Hi Andrew,
> > > could you consider the following patch for the Linus tree, please?
> > > The discussion took place in this email thread 
> > > http://lkml.org/lkml/2010/11/10/114.
> > > The patch is based on top of 151f52f09c572 commit in the Linus tree.
> > > 
> > > Please let me know if there I should route this patch through somebody
> > > else.
> > > 
> > > Thanks!
> > > 
> > > ---
> > > >From 30238aaec758988493af793939f14b0ba83dc4b3 Mon Sep 17 00:00:00 2001
> > > From: Michal Hocko <mhocko@suse.cz>
> > > Date: Wed, 10 Nov 2010 13:30:04 +0100
> > > Subject: [PATCH] Make swap accounting default behavior configurable
> > > 
> > > Swap accounting can be configured by CONFIG_CGROUP_MEM_RES_CTLR_SWAP
> > > configuration option and then it is turned on by default. There is
> > > a boot option (noswapaccount) which can disable this feature.
> > > 
> > > This makes it hard for distributors to enable the configuration option
> > > as this feature leads to a bigger memory consumption and this is a no-go
> > > for general purpose distribution kernel. On the other hand swap
> > > accounting may be very usuful for some workloads.
> > 
> > This patch is needed by distros, and distros use the -stable tree, I
> > assume.  Do you see reasons why this patch should be backported into
> > -stable, so distros don't need to patch it themselves?  If so, any
> > particular kernel versions?  2.6.37?
> > 
> > > This patch adds a new configuration option which controls the default
> > > behavior (CGROUP_MEM_RES_CTLR_SWAP_ENABLED). If the option is selected
> > > then the feature is turned on by default.
> > > 
> > > It also adds a new boot parameter swapaccount which (contrary to
> > > noswapaccount) enables the feature. (I would consider swapaccount=yes|no
> > > semantic with removed noswapaccount parameter much better but this
> > > parameter is kind of API which might be in use and unexpected breakage
> > > is no-go.)
> > > 
> > > The default behavior is unchanged (if CONFIG_CGROUP_MEM_RES_CTLR_SWAP is
> > > enabled then CONFIG_CGROUP_MEM_RES_CTLR_SWAP_ENABLED is enabled as well)
> > > 
> > > Signed-off-by: Michal Hocko <mhocko@suse.cz>
> > > Acked-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
> > > ---
> > >  Documentation/kernel-parameters.txt |    3 +++
> > >  init/Kconfig                        |   13 +++++++++++++
> > >  mm/memcontrol.c                     |   15 ++++++++++++++-
> > >  3 files changed, 30 insertions(+), 1 deletions(-)
> > > 
> > > diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
> > > index ed45e98..14eafa5 100644
> > > --- a/Documentation/kernel-parameters.txt
> > > +++ b/Documentation/kernel-parameters.txt
> > > @@ -2385,6 +2385,9 @@ and is between 256 and 4096 characters. It is defined in the file
> > >  			improve throughput, but will also increase the
> > >  			amount of memory reserved for use by the client.
> > >  
> > > +	swapaccount	[KNL] Enable accounting of swap in memory resource
> > > +			controller. (See Documentation/cgroups/memory.txt)
> > 
> > So we have swapaccount and noswapaccount.  Ho hum, "swapaccount=[1|0]"
> > would have been better.
> > 
> I suggested to keep "noswapaccount" for compatibility.
> If you and other guys don't like having two parameters, I don't stick to
> the old parameter.
> 

I don't think "noswapaccount" is important if "enable is default" when 
proper configuration is used ....because it's rarelly used.
 
BTW, memory usage of swap_cgroup is really important ? It consumes 
1 Mbytes per 2G of swap.

Off topic.
I wonder I'll be happy if we can have default config template for all
others as recent "Add Kconfig option for default swappiness" discuss.

Thanks,
-Kame


Thanks,
-Kame



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Re: [PATCH] Make swap accounting default behavior configurable

[Andrew Morton]

On Wed, 17 Nov 2010 09:23:39 +0900 Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> wrote:

> > > 
> > > diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
> > > index ed45e98..14eafa5 100644
> > > --- a/Documentation/kernel-parameters.txt
> > > +++ b/Documentation/kernel-parameters.txt
> > > @@ -2385,6 +2385,9 @@ and is between 256 and 4096 characters. It is defined in the file
> > >  			improve throughput, but will also increase the
> > >  			amount of memory reserved for use by the client.
> > >  
> > > +	swapaccount	[KNL] Enable accounting of swap in memory resource
> > > +			controller. (See Documentation/cgroups/memory.txt)
> > 
> > So we have swapaccount and noswapaccount.  Ho hum, "swapaccount=[1|0]"
> > would have been better.
> > 
> I suggested to keep "noswapaccount" for compatibility.
> If you and other guys don't like having two parameters, I don't stick to
> the old parameter.
> 

Yes, we're stuck with the old one now.

But we should note that "foo=[0|1]" is superior to "foo" and "nofoo". 
Even if we didn't initially intend to add "nofoo".

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Re: [PATCH] Make swap accounting default behavior configurable

[Daisuke Nishimura]

On Tue, 16 Nov 2010 17:12:25 -0800
Andrew Morton <akpm@linux-foundation.org> wrote:

> On Wed, 17 Nov 2010 09:23:39 +0900 Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> wrote:
> 
> > > > 
> > > > diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
> > > > index ed45e98..14eafa5 100644
> > > > --- a/Documentation/kernel-parameters.txt
> > > > +++ b/Documentation/kernel-parameters.txt
> > > > @@ -2385,6 +2385,9 @@ and is between 256 and 4096 characters. It is defined in the file
> > > >  			improve throughput, but will also increase the
> > > >  			amount of memory reserved for use by the client.
> > > >  
> > > > +	swapaccount	[KNL] Enable accounting of swap in memory resource
> > > > +			controller. (See Documentation/cgroups/memory.txt)
> > > 
> > > So we have swapaccount and noswapaccount.  Ho hum, "swapaccount=[1|0]"
> > > would have been better.
> > > 
> > I suggested to keep "noswapaccount" for compatibility.
> > If you and other guys don't like having two parameters, I don't stick to
> > the old parameter.
> > 
> 
> Yes, we're stuck with the old one now.
> 
> But we should note that "foo=[0|1]" is superior to "foo" and "nofoo". 
> Even if we didn't initially intend to add "nofoo".
> 
I see.

Michal-san, could you update your patch to use "swapaccount=[1|0]" ?

Thanks,
Daisuke Nishimura.

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Re: [PATCH] Make swap accounting default behavior configurable

[Michal Hocko]

On Wed 17-11-10 12:28:01, Daisuke Nishimura wrote:
> On Tue, 16 Nov 2010 17:12:25 -0800
> Andrew Morton <akpm@linux-foundation.org> wrote:
> 
> > On Wed, 17 Nov 2010 09:23:39 +0900 Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> wrote:
> > 
> > > > > 
> > > > > diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
> > > > > index ed45e98..14eafa5 100644
> > > > > --- a/Documentation/kernel-parameters.txt
> > > > > +++ b/Documentation/kernel-parameters.txt
> > > > > @@ -2385,6 +2385,9 @@ and is between 256 and 4096 characters. It is defined in the file
> > > > >  			improve throughput, but will also increase the
> > > > >  			amount of memory reserved for use by the client.
> > > > >  
> > > > > +	swapaccount	[KNL] Enable accounting of swap in memory resource
> > > > > +			controller. (See Documentation/cgroups/memory.txt)
> > > > 
> > > > So we have swapaccount and noswapaccount.  Ho hum, "swapaccount=[1|0]"
> > > > would have been better.
> > > > 
> > > I suggested to keep "noswapaccount" for compatibility.
> > > If you and other guys don't like having two parameters, I don't stick to
> > > the old parameter.
> > > 
> > 
> > Yes, we're stuck with the old one now.
> > 
> > But we should note that "foo=[0|1]" is superior to "foo" and "nofoo". 
> > Even if we didn't initially intend to add "nofoo".
> > 
> I see.
> 
> Michal-san, could you update your patch to use "swapaccount=[1|0]" ?

I have noticed that Andrew has already taken the last version of the
patch for -mm tree. Should I still rework it to change swapaccount to
swapaccount=0|1 resp. true|false?

> 
> Thanks,
> Daisuke Nishimura.
-- 
Michal Hocko
L3 team 
SUSE LINUX s.r.o.
Lihovarska 1060/12
190 00 Praha 9    
Czech Republic

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Re: [PATCH] Make swap accounting default behavior configurable

[Daisuke Nishimura]

On Thu, 18 Nov 2010 09:23:32 +0100
Michal Hocko <mhocko@suse.cz> wrote:

> On Wed 17-11-10 12:28:01, Daisuke Nishimura wrote:
> > On Tue, 16 Nov 2010 17:12:25 -0800
> > Andrew Morton <akpm@linux-foundation.org> wrote:
> > 
> > > On Wed, 17 Nov 2010 09:23:39 +0900 Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> wrote:
> > > 
> > > > > > 
> > > > > > diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
> > > > > > index ed45e98..14eafa5 100644
> > > > > > --- a/Documentation/kernel-parameters.txt
> > > > > > +++ b/Documentation/kernel-parameters.txt
> > > > > > @@ -2385,6 +2385,9 @@ and is between 256 and 4096 characters. It is defined in the file
> > > > > >  			improve throughput, but will also increase the
> > > > > >  			amount of memory reserved for use by the client.
> > > > > >  
> > > > > > +	swapaccount	[KNL] Enable accounting of swap in memory resource
> > > > > > +			controller. (See Documentation/cgroups/memory.txt)
> > > > > 
> > > > > So we have swapaccount and noswapaccount.  Ho hum, "swapaccount=[1|0]"
> > > > > would have been better.
> > > > > 
> > > > I suggested to keep "noswapaccount" for compatibility.
> > > > If you and other guys don't like having two parameters, I don't stick to
> > > > the old parameter.
> > > > 
> > > 
> > > Yes, we're stuck with the old one now.
> > > 
> > > But we should note that "foo=[0|1]" is superior to "foo" and "nofoo". 
> > > Even if we didn't initially intend to add "nofoo".
> > > 
> > I see.
> > 
> > Michal-san, could you update your patch to use "swapaccount=[1|0]" ?
> 
> I have noticed that Andrew has already taken the last version of the
> patch for -mm tree. Should I still rework it to change swapaccount to
> swapaccount=0|1 resp. true|false?
> 
It's usual to update a patch into more sophisticated one while it is in -mm tree.
So, I think you'd better to do it(btw, I prefer 0|1 to true|false.
Reading kernel-parameters.txt, 0|1 is more commonly used.).

Thanks,
Daisuke Nishimura.

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Re: [PATCH] Make swap accounting default behavior configurable

[KAMEZAWA Hiroyuki]

On Thu, 18 Nov 2010 17:46:54 +0900
Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> wrote:

> On Thu, 18 Nov 2010 09:23:32 +0100
> Michal Hocko <mhocko@suse.cz> wrote:
> 
> > On Wed 17-11-10 12:28:01, Daisuke Nishimura wrote:
> > > On Tue, 16 Nov 2010 17:12:25 -0800
> > > Andrew Morton <akpm@linux-foundation.org> wrote:
> > > 
> > > > On Wed, 17 Nov 2010 09:23:39 +0900 Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> wrote:
> > > > 
> > > > > > > 
> > > > > > > diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
> > > > > > > index ed45e98..14eafa5 100644
> > > > > > > --- a/Documentation/kernel-parameters.txt
> > > > > > > +++ b/Documentation/kernel-parameters.txt
> > > > > > > @@ -2385,6 +2385,9 @@ and is between 256 and 4096 characters. It is defined in the file
> > > > > > >  			improve throughput, but will also increase the
> > > > > > >  			amount of memory reserved for use by the client.
> > > > > > >  
> > > > > > > +	swapaccount	[KNL] Enable accounting of swap in memory resource
> > > > > > > +			controller. (See Documentation/cgroups/memory.txt)
> > > > > > 
> > > > > > So we have swapaccount and noswapaccount.  Ho hum, "swapaccount=[1|0]"
> > > > > > would have been better.
> > > > > > 
> > > > > I suggested to keep "noswapaccount" for compatibility.
> > > > > If you and other guys don't like having two parameters, I don't stick to
> > > > > the old parameter.
> > > > > 
> > > > 
> > > > Yes, we're stuck with the old one now.
> > > > 
> > > > But we should note that "foo=[0|1]" is superior to "foo" and "nofoo". 
> > > > Even if we didn't initially intend to add "nofoo".
> > > > 
> > > I see.
> > > 
> > > Michal-san, could you update your patch to use "swapaccount=[1|0]" ?
> > 
> > I have noticed that Andrew has already taken the last version of the
> > patch for -mm tree. Should I still rework it to change swapaccount to
> > swapaccount=0|1 resp. true|false?
> > 
> It's usual to update a patch into more sophisticated one while it is in -mm tree.
> So, I think you'd better to do it(btw, I prefer 0|1 to true|false.
> Reading kernel-parameters.txt, 0|1 is more commonly used.).
> 

I vote for 0|1

Thanks,
-Kame

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Re: [PATCH] Make swap accounting default behavior configurable v4

[Michal Hocko]

On Thu 18-11-10 17:53:34, KAMEZAWA Hiroyuki wrote:
> On Thu, 18 Nov 2010 17:46:54 +0900
> Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> wrote:
> 
> > On Thu, 18 Nov 2010 09:23:32 +0100
> > Michal Hocko <mhocko@suse.cz> wrote:
> > 
> > > On Wed 17-11-10 12:28:01, Daisuke Nishimura wrote:
> > > > On Tue, 16 Nov 2010 17:12:25 -0800
> > > > Andrew Morton <akpm@linux-foundation.org> wrote:
[...]
> > > > > Yes, we're stuck with the old one now.
> > > > > 
> > > > > But we should note that "foo=[0|1]" is superior to "foo" and "nofoo". 
> > > > > Even if we didn't initially intend to add "nofoo".
> > > > > 
> > > > I see.
> > > > 
> > > > Michal-san, could you update your patch to use "swapaccount=[1|0]" ?
> > > 
> > > I have noticed that Andrew has already taken the last version of the
> > > patch for -mm tree. Should I still rework it to change swapaccount to
> > > swapaccount=0|1 resp. true|false?
> > > 
> > It's usual to update a patch into more sophisticated one while it is in -mm tree.
> > So, I think you'd better to do it(btw, I prefer 0|1 to true|false.
> > Reading kernel-parameters.txt, 0|1 is more commonly used.).
> > 
> 
> I vote for 0|1

Changes since v3:
* add 0|1 parameter values handling

Changes since v2:
* put the new parameter description to the proper (alphabetically
* sorted)
  place in Documentation/kernel-parameters.txt
  
Changes since v1:
* do not remove noswapaccount parameter and add swapaccount parameter
* instead
* Documentation/kernel-parameters.txt updated)

--- 

Re: [PATCH] Make swap accounting default behavior configurable v4

[Daisuke Nishimura]

On Thu, 18 Nov 2010 10:56:07 +0100
Michal Hocko <mhocko@suse.cz> wrote:

> On Thu 18-11-10 17:53:34, KAMEZAWA Hiroyuki wrote:
> > On Thu, 18 Nov 2010 17:46:54 +0900
> > Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> wrote:
> > 
> > > On Thu, 18 Nov 2010 09:23:32 +0100
> > > Michal Hocko <mhocko@suse.cz> wrote:
> > > 
> > > > On Wed 17-11-10 12:28:01, Daisuke Nishimura wrote:
> > > > > On Tue, 16 Nov 2010 17:12:25 -0800
> > > > > Andrew Morton <akpm@linux-foundation.org> wrote:
> [...]
> > > > > > Yes, we're stuck with the old one now.
> > > > > > 
> > > > > > But we should note that "foo=[0|1]" is superior to "foo" and "nofoo". 
> > > > > > Even if we didn't initially intend to add "nofoo".
> > > > > > 
> > > > > I see.
> > > > > 
> > > > > Michal-san, could you update your patch to use "swapaccount=[1|0]" ?
> > > > 
> > > > I have noticed that Andrew has already taken the last version of the
> > > > patch for -mm tree. Should I still rework it to change swapaccount to
> > > > swapaccount=0|1 resp. true|false?
> > > > 
> > > It's usual to update a patch into more sophisticated one while it is in -mm tree.
> > > So, I think you'd better to do it(btw, I prefer 0|1 to true|false.
> > > Reading kernel-parameters.txt, 0|1 is more commonly used.).
> > > 
> > 
> > I vote for 0|1
> 
> Changes since v3:
> * add 0|1 parameter values handling
> 
> Changes since v2:
> * put the new parameter description to the proper (alphabetically
> * sorted)
>   place in Documentation/kernel-parameters.txt
>   
> Changes since v1:
> * do not remove noswapaccount parameter and add swapaccount parameter
> * instead
> * Documentation/kernel-parameters.txt updated)
> 

I'm sorry again and again, but I think removing "noswapaccount" completely
would be better, as Andrew said first:
> So we have swapaccount and noswapaccount.  Ho hum, "swapaccount=[1|0]"
> would have been better.


Thanks,
Daisuke Nishimura.

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Re: [PATCH] Make swap accounting default behavior configurable v4

[Michal Hocko]

[I am removing stable from CC - to shield them off the discussion]

On Thu 18-11-10 19:14:27, Daisuke Nishimura wrote:
> On Thu, 18 Nov 2010 10:56:07 +0100
> Michal Hocko <mhocko@suse.cz> wrote:
> 
> > On Thu 18-11-10 17:53:34, KAMEZAWA Hiroyuki wrote:
> > > On Thu, 18 Nov 2010 17:46:54 +0900
> > > Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> wrote:
> > > 
> > > > On Thu, 18 Nov 2010 09:23:32 +0100
> > > > Michal Hocko <mhocko@suse.cz> wrote:
> > > > 
> > > > > On Wed 17-11-10 12:28:01, Daisuke Nishimura wrote:
> > > > > > On Tue, 16 Nov 2010 17:12:25 -0800
> > > > > > Andrew Morton <akpm@linux-foundation.org> wrote:
> > [...]
> > > > > > > Yes, we're stuck with the old one now.
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

> > > > > > > 
> > > > > > > But we should note that "foo=[0|1]" is superior to "foo" and "nofoo". 
> > > > > > > Even if we didn't initially intend to add "nofoo".
> > > > > > > 
> > > > > > I see.
> > > > > > 
> > > > > > Michal-san, could you update your patch to use "swapaccount=[1|0]" ?
> > > > > 
> > > > > I have noticed that Andrew has already taken the last version of the
> > > > > patch for -mm tree. Should I still rework it to change swapaccount to
> > > > > swapaccount=0|1 resp. true|false?
> > > > > 
> > > > It's usual to update a patch into more sophisticated one while it is in -mm tree.
> > > > So, I think you'd better to do it(btw, I prefer 0|1 to true|false.
> > > > Reading kernel-parameters.txt, 0|1 is more commonly used.).
> > > > 
> > > 
> > > I vote for 0|1
> > 
> > Changes since v3:
> > * add 0|1 parameter values handling
> > 
> > Changes since v2:
> > * put the new parameter description to the proper (alphabetically
> > * sorted)
> >   place in Documentation/kernel-parameters.txt
> >   
> > Changes since v1:
> > * do not remove noswapaccount parameter and add swapaccount parameter
> > * instead
> > * Documentation/kernel-parameters.txt updated)
> > 
> 
> I'm sorry again and again, but I think removing "noswapaccount" completely
> would be better, as Andrew said first:

I read the above Andrew's statement that we really should stick with the
old parameter.

> > So we have swapaccount and noswapaccount.  Ho hum, "swapaccount=[1|0]"
> > would have been better.
> 
> 
> Thanks,
> Daisuke Nishimura.

-- 
Michal Hocko
L3 team 
SUSE LINUX s.r.o.
Lihovarska 1060/12
190 00 Praha 9    
Czech Republic

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Re: [PATCH] Make swap accounting default behavior configurable v4

[Andrew Morton]

On Thu, 18 Nov 2010 11:23:49 +0100 Michal Hocko <mhocko@suse.cz> wrote:

> > I'm sorry again and again, but I think removing "noswapaccount" completely
> > would be better, as Andrew said first:
> 
> I read the above Andrew's statement that we really should stick with the
> old parameter.

yup.  We shouldn't remove the existing parameter, which people might be
using already.

> > > So we have swapaccount and noswapaccount.  Ho hum, "swapaccount=[1|0]"
> > > would have been better.

What I meant was that it was a mistake to add the "noswapaccount" in
the first place.  We should have made it "swapaccount=0", because that
would leave open the later option of reversing the default, and
enabling "swapaccount=1".

It also give us the option of adding "swapaccount=2"!  Perhaps to
enable alternative swap accounting behaviour.

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