Forwarding to xen-devel --- On Tue, 1/5/10, Kashmira. K. <chimnee@yahoo.com> wrote:> From: Kashmira. K. <chimnee@yahoo.com> > Subject: bigphysarea patch on xen capable linux > To: xen-users@lists.xensource.com > Date: Tuesday, January 5, 2010, 1:31 PM > Hello Xen Experts > > I am trying to port a linux application or rather a user > mode linux driver (not built into the kernel) to Xen capable > linux. This will be running in Dom0. This user mode driver > used the linux pigphysarea patch to allocate large (over > 1Gig) physically contiguous memory. > > I have two questions: > > 1. Is the bigphysarea patch supported on Xen capable > linux? If not what is the maximum physically > contiguous memory Xen provides. > > 2. If I were to run my application in DomU instead of Dom0, > can the bigphysarea patch be used then. > > Thanks in advance. > Kashmira > > > > >_______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
Jan Beulich
2010-Jan-12 08:53 UTC
Re: [Xen-devel] Fw: bigphysarea patch on xen capable linux
>>> "Kashmira. K." <chimnee@yahoo.com> 08.01.10 02:10 >>> > 1. Is the bigphysarea patch supported on Xen capable > linux? If not what is the maximum physically > contiguous memory Xen provides.2Mb is the maximum you can create.> 2. If I were to run my application in DomU instead of Dom0, > can the bigphysarea patch be used then.In a fully virtualized DomU this should be possible (unless you imply to be able to use 1G pages). Jan _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
Kashmira. K.
2010-Jan-12 20:49 UTC
Re: [Xen-devel] Fw: bigphysarea patch on xen capable linux
Hi Jan, I looked at the linux code xen_create_contiguous_region(). It appears the 2MB limit comes from the #define MAX_CONIG_ORGER 9. Could that be modified to get more than 2MB. If not would you have other suggestions of how I can I get around 500M or more of physically contiguous memory on Xen in Dom0 linux. Thanks Kashmira --- On Tue, 1/12/10, Jan Beulich <JBeulich@novell.com> wrote:> From: Jan Beulich <JBeulich@novell.com> > Subject: Re: [Xen-devel] Fw: bigphysarea patch on xen capable linux > To: "Kashmira. K." <chimnee@yahoo.com> > Cc: xen-devel@lists.xensource.com > Date: Tuesday, January 12, 2010, 12:53 AM > >>> "Kashmira. K." <chimnee@yahoo.com> > 08.01.10 02:10 >>> > > 1. Is the bigphysarea patch supported on Xen capable > > linux? If not what is the maximum physically > > contiguous memory Xen provides. > > 2Mb is the maximum you can create. > > > 2. If I were to run my application in DomU instead of > Dom0, > > can the bigphysarea patch be used then. > > In a fully virtualized DomU this should be possible (unless > you imply to > be able to use 1G pages). > > Jan > >_______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
Keir Fraser
2010-Jan-12 21:10 UTC
Re: [Xen-devel] Fw: bigphysarea patch on xen capable linux
You can increase MAX_CONTIG_ORDER and then it could work. The cost is a larger kernel image size for the enlarged static arrays defined immediately above xen_create_contiguous_region(). -- Keir On 12/01/2010 20:49, "Kashmira. K." <chimnee@yahoo.com> wrote:> > Hi Jan, > > I looked at the linux code xen_create_contiguous_region(). It appears the 2MB > limit comes from the #define MAX_CONIG_ORGER 9. Could that be modified to get > more than 2MB. > > If not would you have other suggestions of how I can I get around 500M or more > of physically contiguous memory on Xen in Dom0 linux. > > Thanks > Kashmira > > --- On Tue, 1/12/10, Jan Beulich <JBeulich@novell.com> wrote: > >> From: Jan Beulich <JBeulich@novell.com> >> Subject: Re: [Xen-devel] Fw: bigphysarea patch on xen capable linux >> To: "Kashmira. K." <chimnee@yahoo.com> >> Cc: xen-devel@lists.xensource.com >> Date: Tuesday, January 12, 2010, 12:53 AM >>>>> "Kashmira. K." <chimnee@yahoo.com> >> 08.01.10 02:10 >>> >>> 1. Is the bigphysarea patch supported on Xen capable >>> linux? If not what is the maximum physically >>> contiguous memory Xen provides. >> >> 2Mb is the maximum you can create. >> >>> 2. If I were to run my application in DomU instead of >> Dom0, >>> can the bigphysarea patch be used then. >> >> In a fully virtualized DomU this should be possible (unless >> you imply to >> be able to use 1G pages). >> >> Jan >> >> > > > > > _______________________________________________ > Xen-devel mailing list > Xen-devel@lists.xensource.com > http://lists.xensource.com/xen-devel_______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel