Re: [PATCH V3 RFC 2/2] kvm: Handle yield_to failure return code for potential undercommit case

2012-12-07 Thread Marcelo Tosatti
On Thu, Dec 06, 2012 at 12:29:02PM +0530, Raghavendra K T wrote: > On 12/04/2012 01:26 AM, Marcelo Tosatti wrote: > >On Wed, Nov 28, 2012 at 10:40:56AM +0530, Raghavendra K T wrote: > >>On 11/28/2012 06:42 AM, Marcelo Tosatti wrote: > >>> > >>>Don't understand the reasoning behind why 3 is a good

Re: [PATCH V3 RFC 2/2] kvm: Handle yield_to failure return code for potential undercommit case

2012-12-07 Thread Marcelo Tosatti
On Thu, Dec 06, 2012 at 12:29:02PM +0530, Raghavendra K T wrote: On 12/04/2012 01:26 AM, Marcelo Tosatti wrote: On Wed, Nov 28, 2012 at 10:40:56AM +0530, Raghavendra K T wrote: On 11/28/2012 06:42 AM, Marcelo Tosatti wrote: Don't understand the reasoning behind why 3 is a good choice.

Re: [PATCH V3 RFC 2/2] kvm: Handle yield_to failure return code for potential undercommit case

2012-12-05 Thread Raghavendra K T
On 12/04/2012 01:26 AM, Marcelo Tosatti wrote: On Wed, Nov 28, 2012 at 10:40:56AM +0530, Raghavendra K T wrote: On 11/28/2012 06:42 AM, Marcelo Tosatti wrote: Don't understand the reasoning behind why 3 is a good choice. Here is where I came from. (explaining from scratch for completeness,

Re: [PATCH V3 RFC 2/2] kvm: Handle yield_to failure return code for potential undercommit case

2012-12-05 Thread Raghavendra K T
On 12/04/2012 01:26 AM, Marcelo Tosatti wrote: On Wed, Nov 28, 2012 at 10:40:56AM +0530, Raghavendra K T wrote: On 11/28/2012 06:42 AM, Marcelo Tosatti wrote: Don't understand the reasoning behind why 3 is a good choice. Here is where I came from. (explaining from scratch for completeness,

Re: [PATCH V3 RFC 2/2] kvm: Handle yield_to failure return code for potential undercommit case

2012-12-04 Thread Raghavendra K T
On 12/04/2012 01:26 AM, Marcelo Tosatti wrote: On Wed, Nov 28, 2012 at 10:40:56AM +0530, Raghavendra K T wrote: On 11/28/2012 06:42 AM, Marcelo Tosatti wrote: Don't understand the reasoning behind why 3 is a good choice. Here is where I came from. (explaining from scratch for completeness,

Re: [PATCH V3 RFC 2/2] kvm: Handle yield_to failure return code for potential undercommit case

2012-12-04 Thread Raghavendra K T
On 12/04/2012 01:26 AM, Marcelo Tosatti wrote: On Wed, Nov 28, 2012 at 10:40:56AM +0530, Raghavendra K T wrote: On 11/28/2012 06:42 AM, Marcelo Tosatti wrote: Don't understand the reasoning behind why 3 is a good choice. Here is where I came from. (explaining from scratch for completeness,

Re: [PATCH V3 RFC 2/2] kvm: Handle yield_to failure return code for potential undercommit case

2012-12-03 Thread Marcelo Tosatti
On Wed, Nov 28, 2012 at 10:40:56AM +0530, Raghavendra K T wrote: > On 11/28/2012 06:42 AM, Marcelo Tosatti wrote: > > > >Don't understand the reasoning behind why 3 is a good choice. > > Here is where I came from. (explaining from scratch for > completeness, forgive me :)) > In moderate

Re: [PATCH V3 RFC 2/2] kvm: Handle yield_to failure return code for potential undercommit case

2012-12-03 Thread Marcelo Tosatti
On Wed, Nov 28, 2012 at 10:40:56AM +0530, Raghavendra K T wrote: On 11/28/2012 06:42 AM, Marcelo Tosatti wrote: Don't understand the reasoning behind why 3 is a good choice. Here is where I came from. (explaining from scratch for completeness, forgive me :)) In moderate overcommits, we

Re: [PATCH V3 RFC 2/2] kvm: Handle yield_to failure return code for potential undercommit case

2012-11-29 Thread Raghavendra K T
On 11/29/2012 05:46 PM, Gleb Natapov wrote: On Wed, Nov 28, 2012 at 10:40:56AM +0530, Raghavendra K T wrote: On 11/28/2012 06:42 AM, Marcelo Tosatti wrote: Don't understand the reasoning behind why 3 is a good choice. Here is where I came from. (explaining from scratch for completeness,

Re: [PATCH V3 RFC 2/2] kvm: Handle yield_to failure return code for potential undercommit case

2012-11-29 Thread Gleb Natapov
On Wed, Nov 28, 2012 at 10:40:56AM +0530, Raghavendra K T wrote: > On 11/28/2012 06:42 AM, Marcelo Tosatti wrote: > > > >Don't understand the reasoning behind why 3 is a good choice. > > Here is where I came from. (explaining from scratch for > completeness, forgive me :)) > In moderate

Re: [PATCH V3 RFC 2/2] kvm: Handle yield_to failure return code for potential undercommit case

2012-11-29 Thread Gleb Natapov
On Wed, Nov 28, 2012 at 10:40:56AM +0530, Raghavendra K T wrote: On 11/28/2012 06:42 AM, Marcelo Tosatti wrote: Don't understand the reasoning behind why 3 is a good choice. Here is where I came from. (explaining from scratch for completeness, forgive me :)) In moderate overcommits, we

Re: [PATCH V3 RFC 2/2] kvm: Handle yield_to failure return code for potential undercommit case

2012-11-29 Thread Raghavendra K T
On 11/29/2012 05:46 PM, Gleb Natapov wrote: On Wed, Nov 28, 2012 at 10:40:56AM +0530, Raghavendra K T wrote: On 11/28/2012 06:42 AM, Marcelo Tosatti wrote: Don't understand the reasoning behind why 3 is a good choice. Here is where I came from. (explaining from scratch for completeness,

Re: [PATCH V3 RFC 2/2] kvm: Handle yield_to failure return code for potential undercommit case

2012-11-27 Thread Raghavendra K T
On 11/28/2012 06:42 AM, Marcelo Tosatti wrote: Don't understand the reasoning behind why 3 is a good choice. Here is where I came from. (explaining from scratch for completeness, forgive me :)) In moderate overcommits, we can falsely exit from ple handler even when we have preempted task of

Re: [PATCH V3 RFC 2/2] kvm: Handle yield_to failure return code for potential undercommit case

2012-11-27 Thread Marcelo Tosatti
Don't understand the reasoning behind why 3 is a good choice. On Mon, Nov 26, 2012 at 05:38:04PM +0530, Raghavendra K T wrote: > From: Raghavendra K T > > yield_to returns -ESRCH, When source and target of yield_to > run queue length is one. When we see three successive failures of > yield_to

Re: [PATCH V3 RFC 2/2] kvm: Handle yield_to failure return code for potential undercommit case

2012-11-27 Thread Andrew Jones
On Tue, Nov 27, 2012 at 03:57:25PM +0530, Raghavendra K T wrote: > On 11/26/2012 07:13 PM, Andrew Jones wrote: > >On Mon, Nov 26, 2012 at 05:38:04PM +0530, Raghavendra K T wrote: > >>From: Raghavendra K T > >> > >>yield_to returns -ESRCH, When source and target of yield_to > >>run queue length is

Re: [PATCH V3 RFC 2/2] kvm: Handle yield_to failure return code for potential undercommit case

2012-11-27 Thread Raghavendra K T
On 11/26/2012 07:13 PM, Andrew Jones wrote: On Mon, Nov 26, 2012 at 05:38:04PM +0530, Raghavendra K T wrote: From: Raghavendra K T yield_to returns -ESRCH, When source and target of yield_to run queue length is one. When we see three successive failures of yield_to we assume we are in

Re: [PATCH V3 RFC 2/2] kvm: Handle yield_to failure return code for potential undercommit case

2012-11-27 Thread Raghavendra K T
On 11/26/2012 07:13 PM, Andrew Jones wrote: On Mon, Nov 26, 2012 at 05:38:04PM +0530, Raghavendra K T wrote: From: Raghavendra K T raghavendra...@linux.vnet.ibm.com yield_to returns -ESRCH, When source and target of yield_to run queue length is one. When we see three successive failures of

Re: [PATCH V3 RFC 2/2] kvm: Handle yield_to failure return code for potential undercommit case

2012-11-27 Thread Andrew Jones
On Tue, Nov 27, 2012 at 03:57:25PM +0530, Raghavendra K T wrote: On 11/26/2012 07:13 PM, Andrew Jones wrote: On Mon, Nov 26, 2012 at 05:38:04PM +0530, Raghavendra K T wrote: From: Raghavendra K T raghavendra...@linux.vnet.ibm.com yield_to returns -ESRCH, When source and target of yield_to

Re: [PATCH V3 RFC 2/2] kvm: Handle yield_to failure return code for potential undercommit case

2012-11-27 Thread Marcelo Tosatti
Don't understand the reasoning behind why 3 is a good choice. On Mon, Nov 26, 2012 at 05:38:04PM +0530, Raghavendra K T wrote: From: Raghavendra K T raghavendra...@linux.vnet.ibm.com yield_to returns -ESRCH, When source and target of yield_to run queue length is one. When we see three

Re: [PATCH V3 RFC 2/2] kvm: Handle yield_to failure return code for potential undercommit case

2012-11-27 Thread Raghavendra K T
On 11/28/2012 06:42 AM, Marcelo Tosatti wrote: Don't understand the reasoning behind why 3 is a good choice. Here is where I came from. (explaining from scratch for completeness, forgive me :)) In moderate overcommits, we can falsely exit from ple handler even when we have preempted task of

Re: [PATCH V3 RFC 2/2] kvm: Handle yield_to failure return code for potential undercommit case

2012-11-26 Thread Andrew Jones
On Mon, Nov 26, 2012 at 02:43:02PM +0100, Andrew Jones wrote: > On Mon, Nov 26, 2012 at 05:38:04PM +0530, Raghavendra K T wrote: > > From: Raghavendra K T > > > > yield_to returns -ESRCH, When source and target of yield_to > > run queue length is one. When we see three successive failures of > >

Re: [PATCH V3 RFC 2/2] kvm: Handle yield_to failure return code for potential undercommit case

2012-11-26 Thread Andrew Jones
On Mon, Nov 26, 2012 at 05:38:04PM +0530, Raghavendra K T wrote: > From: Raghavendra K T > > yield_to returns -ESRCH, When source and target of yield_to > run queue length is one. When we see three successive failures of > yield_to we assume we are in potential undercommit case and abort > from

[PATCH V3 RFC 2/2] kvm: Handle yield_to failure return code for potential undercommit case

2012-11-26 Thread Raghavendra K T
From: Raghavendra K T yield_to returns -ESRCH, When source and target of yield_to run queue length is one. When we see three successive failures of yield_to we assume we are in potential undercommit case and abort from PLE handler. The assumption is backed by low probability of wrong decision

[PATCH V3 RFC 2/2] kvm: Handle yield_to failure return code for potential undercommit case

2012-11-26 Thread Raghavendra K T
From: Raghavendra K T raghavendra...@linux.vnet.ibm.com yield_to returns -ESRCH, When source and target of yield_to run queue length is one. When we see three successive failures of yield_to we assume we are in potential undercommit case and abort from PLE handler. The assumption is backed by low

Re: [PATCH V3 RFC 2/2] kvm: Handle yield_to failure return code for potential undercommit case

2012-11-26 Thread Andrew Jones
On Mon, Nov 26, 2012 at 05:38:04PM +0530, Raghavendra K T wrote: From: Raghavendra K T raghavendra...@linux.vnet.ibm.com yield_to returns -ESRCH, When source and target of yield_to run queue length is one. When we see three successive failures of yield_to we assume we are in potential

Re: [PATCH V3 RFC 2/2] kvm: Handle yield_to failure return code for potential undercommit case

2012-11-26 Thread Andrew Jones
On Mon, Nov 26, 2012 at 02:43:02PM +0100, Andrew Jones wrote: On Mon, Nov 26, 2012 at 05:38:04PM +0530, Raghavendra K T wrote: From: Raghavendra K T raghavendra...@linux.vnet.ibm.com yield_to returns -ESRCH, When source and target of yield_to run queue length is one. When we see three