David Vrabel
2012-May-04 16:01 UTC
[PATCH] x86: make the dom0_max_vcpus option more flexible
From: David Vrabel <david.vrabel@citrix.com>
The dom0_max_vcpus command line option only allows the exact number of
VCPUs for dom0 to be set. It is not possible to say "up to N VCPUs
but no more than the number physically present."
Add min: and max: prefixes to the option to set a minimum number of
VCPUs, and a maximum which does not exceed the number of PCPUs.
For example, with "dom0_max_vcpus=min:4,max:8":
PCPUs Dom0 VCPUs
2 4
4 4
6 6
8 8
10 8
The existing behaviour of "dom0_max_vcpus=N" still works as before.
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
---
docs/misc/xen-command-line.markdown | 29 +++++++++++++++++++++++++++--
xen/arch/x86/domain_build.c | 23 ++++++++++++++++++++++-
2 files changed, 49 insertions(+), 3 deletions(-)
diff --git a/docs/misc/xen-command-line.markdown
b/docs/misc/xen-command-line.markdown
index a6195f2..5f0c2cd 100644
--- a/docs/misc/xen-command-line.markdown
+++ b/docs/misc/xen-command-line.markdown
@@ -272,10 +272,35 @@ Specify the bit width of the DMA heap.
### dom0\_ioports\_disable
### dom0\_max\_vcpus
+
+Either:
+
> `= <integer>`
-Specify the maximum number of vcpus to give to dom0. This defaults
-to the number of pcpus on the host.
+The maximum number of VCPUs to give to dom0. This number of VCPUs can
+be more than the number of PCPUs on the host. The default is the
+number of PCPUs.
+
+Or:
+
+> `= List of ( min:<integer> | max:<integer> )`
+
+With the `min:` option dom0 will have at least this minimum number of
+VCPUs (default: 1). This may be more than the number of PCPUs on the
+host.
+
+With the `max:` option dom0 will have a VCPUs for each PCPUs but no
+more than this maximum number (default: unlimited).
+
+For example, with `dom0_max_vcpus=min:4,max:8`:
+
+ Number of
+ PCPUs | Dom0 VCPUs
+ 2 | 4
+ 4 | 4
+ 6 | 6
+ 8 | 8
+ 10 | 8
### dom0\_mem (ia64)
> `= <size>`
diff --git a/xen/arch/x86/domain_build.c b/xen/arch/x86/domain_build.c
index b3c5d4c..5407f8d 100644
--- a/xen/arch/x86/domain_build.c
+++ b/xen/arch/x86/domain_build.c
@@ -83,7 +83,24 @@ static void __init parse_dom0_mem(const char *s)
custom_param("dom0_mem", parse_dom0_mem);
static unsigned int __initdata opt_dom0_max_vcpus;
-integer_param("dom0_max_vcpus", opt_dom0_max_vcpus);
+static unsigned int __initdata opt_dom0_max_vcpus_min = 1;
+static unsigned int __initdata opt_dom0_max_vcpus_max = UINT_MAX;
+
+static void __init parse_dom0_max_vcpus(const char *s)
+{
+ do {
+ if ( !strncmp(s, "min:", 4) )
+ opt_dom0_max_vcpus_min = simple_strtoul(s+4, &s, 0);
+ else if ( !strncmp(s, "max:", 4) )
+ opt_dom0_max_vcpus_max = simple_strtoul(s+4, &s, 0);
+ else
+ opt_dom0_max_vcpus = simple_strtoul(s, &s, 0);
+ if ( *s != '','' )
+ break;
+ } while ( *s++ == '','' );
+
+}
+custom_param("dom0_max_vcpus", parse_dom0_max_vcpus);
struct vcpu *__init alloc_dom0_vcpu0(void)
{
@@ -91,6 +108,10 @@ struct vcpu *__init alloc_dom0_vcpu0(void)
opt_dom0_max_vcpus = num_cpupool_cpus(cpupool0);
if ( opt_dom0_max_vcpus > MAX_VIRT_CPUS )
opt_dom0_max_vcpus = MAX_VIRT_CPUS;
+ if ( opt_dom0_max_vcpus_min > opt_dom0_max_vcpus )
+ opt_dom0_max_vcpus = opt_dom0_max_vcpus_min;
+ if ( opt_dom0_max_vcpus_max < opt_dom0_max_vcpus )
+ opt_dom0_max_vcpus = opt_dom0_max_vcpus_max;
dom0->vcpu = xzalloc_array(struct vcpu *, opt_dom0_max_vcpus);
if ( !dom0->vcpu )
--
1.7.2.5
Jan Beulich
2012-May-04 16:12 UTC
Re: [PATCH] x86: make the dom0_max_vcpus option more flexible
>>> On 04.05.12 at 18:01, David Vrabel <david.vrabel@citrix.com> wrote: > From: David Vrabel <david.vrabel@citrix.com> > > The dom0_max_vcpus command line option only allows the exact number of > VCPUs for dom0 to be set. It is not possible to say "up to N VCPUs > but no more than the number physically present." > > Add min: and max: prefixes to the option to set a minimum number of > VCPUs, and a maximum which does not exceed the number of PCPUs. > > For example, with "dom0_max_vcpus=min:4,max:8":Both "...max...=min:..." and "...max...=max:" look pretty odd to me; how about simply allowing a range along with a simple number (since negative values make no sense, omitting either side of the range would be supportable if necessary.> PCPUs Dom0 VCPUs > 2 4 > 4 4 > 6 6 > 8 8 > 10 8 > > The existing behaviour of "dom0_max_vcpus=N" still works as before. > > Signed-off-by: David Vrabel <david.vrabel@citrix.com> > --- > docs/misc/xen-command-line.markdown | 29 +++++++++++++++++++++++++++-- > xen/arch/x86/domain_build.c | 23 ++++++++++++++++++++++- > 2 files changed, 49 insertions(+), 3 deletions(-) > > diff --git a/docs/misc/xen-command-line.markdown > b/docs/misc/xen-command-line.markdown > index a6195f2..5f0c2cd 100644 > --- a/docs/misc/xen-command-line.markdown > +++ b/docs/misc/xen-command-line.markdown > @@ -272,10 +272,35 @@ Specify the bit width of the DMA heap. > > ### dom0\_ioports\_disable > ### dom0\_max\_vcpus > + > +Either: > + > > `= <integer>` > > -Specify the maximum number of vcpus to give to dom0. This defaults > -to the number of pcpus on the host. > +The maximum number of VCPUs to give to dom0. This number of VCPUs can > +be more than the number of PCPUs on the host. The default is the > +number of PCPUs. > + > +Or: > + > +> `= List of ( min:<integer> | max:<integer> )` > + > +With the `min:` option dom0 will have at least this minimum number of > +VCPUs (default: 1). This may be more than the number of PCPUs on the > +host. > + > +With the `max:` option dom0 will have a VCPUs for each PCPUs but no > +more than this maximum number (default: unlimited). > + > +For example, with `dom0_max_vcpus=min:4,max:8`: > + > + Number of > + PCPUs | Dom0 VCPUs > + 2 | 4 > + 4 | 4 > + 6 | 6 > + 8 | 8 > + 10 | 8 > > ### dom0\_mem (ia64) > > `= <size>` > diff --git a/xen/arch/x86/domain_build.c b/xen/arch/x86/domain_build.c > index b3c5d4c..5407f8d 100644 > --- a/xen/arch/x86/domain_build.c > +++ b/xen/arch/x86/domain_build.c > @@ -83,7 +83,24 @@ static void __init parse_dom0_mem(const char *s) > custom_param("dom0_mem", parse_dom0_mem); > > static unsigned int __initdata opt_dom0_max_vcpus; > -integer_param("dom0_max_vcpus", opt_dom0_max_vcpus); > +static unsigned int __initdata opt_dom0_max_vcpus_min = 1; > +static unsigned int __initdata opt_dom0_max_vcpus_max = UINT_MAX; > + > +static void __init parse_dom0_max_vcpus(const char *s) > +{ > + do { > + if ( !strncmp(s, "min:", 4) ) > + opt_dom0_max_vcpus_min = simple_strtoul(s+4, &s, 0); > + else if ( !strncmp(s, "max:", 4) ) > + opt_dom0_max_vcpus_max = simple_strtoul(s+4, &s, 0); > + else > + opt_dom0_max_vcpus = simple_strtoul(s, &s, 0); > + if ( *s != '','' ) > + break; > + } while ( *s++ == '','' ); > + > +} > +custom_param("dom0_max_vcpus", parse_dom0_max_vcpus); > > struct vcpu *__init alloc_dom0_vcpu0(void) > { > @@ -91,6 +108,10 @@ struct vcpu *__init alloc_dom0_vcpu0(void) > opt_dom0_max_vcpus = num_cpupool_cpus(cpupool0); > if ( opt_dom0_max_vcpus > MAX_VIRT_CPUS ) > opt_dom0_max_vcpus = MAX_VIRT_CPUS; > + if ( opt_dom0_max_vcpus_min > opt_dom0_max_vcpus ) > + opt_dom0_max_vcpus = opt_dom0_max_vcpus_min;Enlarging the value after the MAX_VIRT_CPUS range check must not be done. You probably simply want to move your addition up two lines.> + if ( opt_dom0_max_vcpus_max < opt_dom0_max_vcpus ) > + opt_dom0_max_vcpus = opt_dom0_max_vcpus_max;But please avoid ...=max: (number lost for some reason) rendering the box unbootable (I''d say a maximum of zero should be interpreted as 1). Jan> > dom0->vcpu = xzalloc_array(struct vcpu *, opt_dom0_max_vcpus); > if ( !dom0->vcpu ) > -- > 1.7.2.5
David Vrabel
2012-May-04 16:26 UTC
Re: [PATCH] x86: make the dom0_max_vcpus option more flexible
On 04/05/12 17:12, Jan Beulich wrote:>>>> On 04.05.12 at 18:01, David Vrabel <david.vrabel@citrix.com> wrote: >> From: David Vrabel <david.vrabel@citrix.com> >> >> The dom0_max_vcpus command line option only allows the exact number of >> VCPUs for dom0 to be set. It is not possible to say "up to N VCPUs >> but no more than the number physically present." >> >> Add min: and max: prefixes to the option to set a minimum number of >> VCPUs, and a maximum which does not exceed the number of PCPUs. >> >> For example, with "dom0_max_vcpus=min:4,max:8": > > Both "...max...=min:..." and "...max...=max:" look pretty odd to me; > how about simply allowing a range along with a simple number (since > negative values make no sense, omitting either side of the range would > be supportable if necessary.I was copying the way dom0_mem worked but yeah, it''s not very pretty. Is dom0_max_vcpus=<min>-<max> (e.g., dom0_max_vcpus=4-8) what you were thinking of? Using a single value would have to set both <min> and <max> or the behaviour of the option changes (i.e., =N is the same as =N-N). David
David Vrabel
2012-May-04 18:18 UTC
Re: [PATCH] x86: make the dom0_max_vcpus option more flexible
On 04/05/12 17:26, David Vrabel wrote:> On 04/05/12 17:12, Jan Beulich wrote: >>>>> On 04.05.12 at 18:01, David Vrabel <david.vrabel@citrix.com> wrote: >>> From: David Vrabel <david.vrabel@citrix.com> >>> >>> The dom0_max_vcpus command line option only allows the exact number of >>> VCPUs for dom0 to be set. It is not possible to say "up to N VCPUs >>> but no more than the number physically present." >>> >>> Add min: and max: prefixes to the option to set a minimum number of >>> VCPUs, and a maximum which does not exceed the number of PCPUs. >>> >>> For example, with "dom0_max_vcpus=min:4,max:8": >> >> Both "...max...=min:..." and "...max...=max:" look pretty odd to me; >> how about simply allowing a range along with a simple number (since >> negative values make no sense, omitting either side of the range would >> be supportable if necessary. > > I was copying the way dom0_mem worked but yeah, it''s not very pretty. > > Is dom0_max_vcpus=<min>-<max> (e.g., dom0_max_vcpus=4-8) what you were > thinking of? > > Using a single value would have to set both <min> and <max> or the > behaviour of the option changes (i.e., =N is the same as =N-N).This is what I ended up with. 8<------------------------------ From af1543965db76ab81139de7f072a7c4daf61157f Mon Sep 17 00:00:00 2001 From: David Vrabel <david.vrabel@citrix.com> Date: Fri, 4 May 2012 16:09:52 +0100 Subject: [PATCH] x86: make the dom0_max_vcpus option more flexible The dom0_max_vcpus command line option only allows the exact number of VCPUs for dom0 to be set. It is not possible to say "up to N VCPUs but no more than the number physically present." Allow a range for the option to set a minimum number of VCPUs, and a maximum which does not exceed the number of PCPUs. For example, with "dom0_max_vcpus=4-8": PCPUs Dom0 VCPUs 2 4 4 4 6 6 8 8 10 8 Existing command lines with "dom0_max_vcpus=N" still work as before. Signed-off-by: David Vrabel <david.vrabel@citrix.com> --- docs/misc/xen-command-line.markdown | 29 +++++++++++++++++++++-- xen/arch/x86/domain_build.c | 43 +++++++++++++++++++++++++--------- 2 files changed, 57 insertions(+), 15 deletions(-) diff --git a/docs/misc/xen-command-line.markdown b/docs/misc/xen-command-line.markdown index a6195f2..4e4f713 100644 --- a/docs/misc/xen-command-line.markdown +++ b/docs/misc/xen-command-line.markdown @@ -272,10 +272,33 @@ Specify the bit width of the DMA heap. ### dom0\_ioports\_disable ### dom0\_max\_vcpus -> `= <integer>` -Specify the maximum number of vcpus to give to dom0. This defaults -to the number of pcpus on the host. +Either: + +> `= <integer>`. + +The number of VCPUs to give to dom0. This number of VCPUs can be more +than the number of PCPUs on the host. The default is the number of +PCPUs. + +Or: + +> `= <min>-<max>` where `<min>` and `<max>` are integers. + +Gives dom0 a number of VCPUs equal to the number of PCPUs, but always +at least `<min>` and no more than `<max>`. Using `<min>` may give +more VCPUs than PCPUs. `<min>` or `<max>` may be omitted and the +defaults of 1 and unlimited respectively are used instead. + +For example, with `dom0_max_vcpus=4-8`: + + Number of + PCPUs | Dom0 VCPUs + 2 | 4 + 4 | 4 + 6 | 6 + 8 | 8 + 10 | 8 ### dom0\_mem (ia64) > `= <size>` diff --git a/xen/arch/x86/domain_build.c b/xen/arch/x86/domain_build.c index b3c5d4c..686b626 100644 --- a/xen/arch/x86/domain_build.c +++ b/xen/arch/x86/domain_build.c @@ -82,20 +82,39 @@ static void __init parse_dom0_mem(const char *s) } custom_param("dom0_mem", parse_dom0_mem); -static unsigned int __initdata opt_dom0_max_vcpus; -integer_param("dom0_max_vcpus", opt_dom0_max_vcpus); +static unsigned int __initdata opt_dom0_max_vcpus_min = 1; +static unsigned int __initdata opt_dom0_max_vcpus_max = UINT_MAX; + +static void __init parse_dom0_max_vcpus(const char *s) +{ + if (*s == ''-'') /* -M */ + opt_dom0_max_vcpus_max = simple_strtoul(s + 1, &s, 0); + else { /* N, N-, or N-M */ + opt_dom0_max_vcpus_min = simple_strtoul(s, &s, 0); + if (*s++ == ''\0'') /* N */ + opt_dom0_max_vcpus_max = opt_dom0_max_vcpus_min; + else if (*s != ''\0'') /* N-M */ + opt_dom0_max_vcpus_max = simple_strtoul(s, &s, 0); + } +} +custom_param("dom0_max_vcpus", parse_dom0_max_vcpus); struct vcpu *__init alloc_dom0_vcpu0(void) { - if ( opt_dom0_max_vcpus == 0 ) - opt_dom0_max_vcpus = num_cpupool_cpus(cpupool0); - if ( opt_dom0_max_vcpus > MAX_VIRT_CPUS ) - opt_dom0_max_vcpus = MAX_VIRT_CPUS; + unsigned max_vcpus; + + max_vcpus = num_cpupool_cpus(cpupool0); + if ( opt_dom0_max_vcpus_min > max_vcpus ) + max_vcpus = opt_dom0_max_vcpus_min; + if ( opt_dom0_max_vcpus_max < max_vcpus ) + max_vcpus = opt_dom0_max_vcpus_max; + if ( max_vcpus > MAX_VIRT_CPUS ) + max_vcpus = MAX_VIRT_CPUS; - dom0->vcpu = xzalloc_array(struct vcpu *, opt_dom0_max_vcpus); + dom0->vcpu = xzalloc_array(struct vcpu *, max_vcpus); if ( !dom0->vcpu ) return NULL; - dom0->max_vcpus = opt_dom0_max_vcpus; + dom0->max_vcpus = max_vcpus; return alloc_vcpu(dom0, 0, 0); } @@ -185,11 +204,11 @@ static unsigned long __init compute_dom0_nr_pages( unsigned long max_pages = dom0_max_nrpages; /* Reserve memory for further dom0 vcpu-struct allocations... */ - avail -= (opt_dom0_max_vcpus - 1UL) + avail -= (d->max_vcpus - 1UL) << get_order_from_bytes(sizeof(struct vcpu)); /* ...and compat_l4''s, if needed. */ if ( is_pv_32on64_domain(d) ) - avail -= opt_dom0_max_vcpus - 1; + avail -= d->max_vcpus - 1; /* Reserve memory for iommu_dom0_init() (rough estimate). */ if ( iommu_enabled ) @@ -883,10 +902,10 @@ int __init construct_dom0( for ( i = 0; i < XEN_LEGACY_MAX_VCPUS; i++ ) shared_info(d, vcpu_info[i].evtchn_upcall_mask) = 1; - printk("Dom0 has maximum %u VCPUs\n", opt_dom0_max_vcpus); + printk("Dom0 has maximum %u VCPUs\n", d->max_vcpus); cpu = cpumask_first(cpupool0->cpu_valid); - for ( i = 1; i < opt_dom0_max_vcpus; i++ ) + for ( i = 1; i < d->max_vcpus; i++ ) { cpu = cpumask_cycle(cpu, cpupool0->cpu_valid); (void)alloc_vcpu(d, i, cpu); -- 1.7.2.5
Jan Beulich
2012-May-07 06:42 UTC
Re: [PATCH] x86: make the dom0_max_vcpus option more flexible
>>> On 04.05.12 at 18:26, David Vrabel <david.vrabel@citrix.com> wrote: > On 04/05/12 17:12, Jan Beulich wrote: >>>>> On 04.05.12 at 18:01, David Vrabel <david.vrabel@citrix.com> wrote: >>> From: David Vrabel <david.vrabel@citrix.com> >>> >>> The dom0_max_vcpus command line option only allows the exact number of >>> VCPUs for dom0 to be set. It is not possible to say "up to N VCPUs >>> but no more than the number physically present." >>> >>> Add min: and max: prefixes to the option to set a minimum number of >>> VCPUs, and a maximum which does not exceed the number of PCPUs. >>> >>> For example, with "dom0_max_vcpus=min:4,max:8": >> >> Both "...max...=min:..." and "...max...=max:" look pretty odd to me; >> how about simply allowing a range along with a simple number (since >> negative values make no sense, omitting either side of the range would >> be supportable if necessary. > > I was copying the way dom0_mem worked but yeah, it''s not very pretty. > > Is dom0_max_vcpus=<min>-<max> (e.g., dom0_max_vcpus=4-8) what you were > thinking of?Yes.> Using a single value would have to set both <min> and <max> or the > behaviour of the option changes (i.e., =N is the same as =N-N).That sounds plausible. Jan
Jan Beulich
2012-May-07 08:19 UTC
Re: [PATCH] x86: make the dom0_max_vcpus option more flexible
>>> On 04.05.12 at 20:18, David Vrabel <david.vrabel@citrix.com> wrote: > On 04/05/12 17:26, David Vrabel wrote: >> On 04/05/12 17:12, Jan Beulich wrote: >>>>>> On 04.05.12 at 18:01, David Vrabel <david.vrabel@citrix.com> wrote: >>>> From: David Vrabel <david.vrabel@citrix.com> >>>> >>>> The dom0_max_vcpus command line option only allows the exact number of >>>> VCPUs for dom0 to be set. It is not possible to say "up to N VCPUs >>>> but no more than the number physically present." >>>> >>>> Add min: and max: prefixes to the option to set a minimum number of >>>> VCPUs, and a maximum which does not exceed the number of PCPUs. >>>> >>>> For example, with "dom0_max_vcpus=min:4,max:8": >>> >>> Both "...max...=min:..." and "...max...=max:" look pretty odd to me; >>> how about simply allowing a range along with a simple number (since >>> negative values make no sense, omitting either side of the range would >>> be supportable if necessary. >> >> I was copying the way dom0_mem worked but yeah, it''s not very pretty. >> >> Is dom0_max_vcpus=<min>-<max> (e.g., dom0_max_vcpus=4-8) what you were >> thinking of? >> >> Using a single value would have to set both <min> and <max> or the >> behaviour of the option changes (i.e., =N is the same as =N-N). > > This is what I ended up with. > > 8<------------------------------ > From af1543965db76ab81139de7f072a7c4daf61157f Mon Sep 17 00:00:00 2001 > From: David Vrabel <david.vrabel@citrix.com> > Date: Fri, 4 May 2012 16:09:52 +0100 > Subject: [PATCH] x86: make the dom0_max_vcpus option more flexible > > The dom0_max_vcpus command line option only allows the exact number of > VCPUs for dom0 to be set. It is not possible to say "up to N VCPUs > but no more than the number physically present." > > Allow a range for the option to set a minimum number of VCPUs, and a > maximum which does not exceed the number of PCPUs. > > For example, with "dom0_max_vcpus=4-8": > > PCPUs Dom0 VCPUs > 2 4 > 4 4 > 6 6 > 8 8 > 10 8 > > Existing command lines with "dom0_max_vcpus=N" still work as before. > > Signed-off-by: David Vrabel <david.vrabel@citrix.com>Acked-by: Jan Beulich <jbeulich@suse.com> But I''m not sure whether this qualifies for going in for 4.2... Jan> --- > docs/misc/xen-command-line.markdown | 29 +++++++++++++++++++++-- > xen/arch/x86/domain_build.c | 43 +++++++++++++++++++++++++--------- > 2 files changed, 57 insertions(+), 15 deletions(-) > > diff --git a/docs/misc/xen-command-line.markdown > b/docs/misc/xen-command-line.markdown > index a6195f2..4e4f713 100644 > --- a/docs/misc/xen-command-line.markdown > +++ b/docs/misc/xen-command-line.markdown > @@ -272,10 +272,33 @@ Specify the bit width of the DMA heap. > > ### dom0\_ioports\_disable > ### dom0\_max\_vcpus > -> `= <integer>` > > -Specify the maximum number of vcpus to give to dom0. This defaults > -to the number of pcpus on the host. > +Either: > + > +> `= <integer>`. > + > +The number of VCPUs to give to dom0. This number of VCPUs can be more > +than the number of PCPUs on the host. The default is the number of > +PCPUs. > + > +Or: > + > +> `= <min>-<max>` where `<min>` and `<max>` are integers. > + > +Gives dom0 a number of VCPUs equal to the number of PCPUs, but always > +at least `<min>` and no more than `<max>`. Using `<min>` may give > +more VCPUs than PCPUs. `<min>` or `<max>` may be omitted and the > +defaults of 1 and unlimited respectively are used instead. > + > +For example, with `dom0_max_vcpus=4-8`: > + > + Number of > + PCPUs | Dom0 VCPUs > + 2 | 4 > + 4 | 4 > + 6 | 6 > + 8 | 8 > + 10 | 8 > > ### dom0\_mem (ia64) > > `= <size>` > diff --git a/xen/arch/x86/domain_build.c b/xen/arch/x86/domain_build.c > index b3c5d4c..686b626 100644 > --- a/xen/arch/x86/domain_build.c > +++ b/xen/arch/x86/domain_build.c > @@ -82,20 +82,39 @@ static void __init parse_dom0_mem(const char *s) > } > custom_param("dom0_mem", parse_dom0_mem); > > -static unsigned int __initdata opt_dom0_max_vcpus; > -integer_param("dom0_max_vcpus", opt_dom0_max_vcpus); > +static unsigned int __initdata opt_dom0_max_vcpus_min = 1; > +static unsigned int __initdata opt_dom0_max_vcpus_max = UINT_MAX; > + > +static void __init parse_dom0_max_vcpus(const char *s) > +{ > + if (*s == ''-'') /* -M */ > + opt_dom0_max_vcpus_max = simple_strtoul(s + 1, &s, 0); > + else { /* N, N-, or N-M */ > + opt_dom0_max_vcpus_min = simple_strtoul(s, &s, 0); > + if (*s++ == ''\0'') /* N */ > + opt_dom0_max_vcpus_max = opt_dom0_max_vcpus_min; > + else if (*s != ''\0'') /* N-M */ > + opt_dom0_max_vcpus_max = simple_strtoul(s, &s, 0); > + } > +} > +custom_param("dom0_max_vcpus", parse_dom0_max_vcpus); > > struct vcpu *__init alloc_dom0_vcpu0(void) > { > - if ( opt_dom0_max_vcpus == 0 ) > - opt_dom0_max_vcpus = num_cpupool_cpus(cpupool0); > - if ( opt_dom0_max_vcpus > MAX_VIRT_CPUS ) > - opt_dom0_max_vcpus = MAX_VIRT_CPUS; > + unsigned max_vcpus; > + > + max_vcpus = num_cpupool_cpus(cpupool0); > + if ( opt_dom0_max_vcpus_min > max_vcpus ) > + max_vcpus = opt_dom0_max_vcpus_min; > + if ( opt_dom0_max_vcpus_max < max_vcpus ) > + max_vcpus = opt_dom0_max_vcpus_max; > + if ( max_vcpus > MAX_VIRT_CPUS ) > + max_vcpus = MAX_VIRT_CPUS; > > - dom0->vcpu = xzalloc_array(struct vcpu *, opt_dom0_max_vcpus); > + dom0->vcpu = xzalloc_array(struct vcpu *, max_vcpus); > if ( !dom0->vcpu ) > return NULL; > - dom0->max_vcpus = opt_dom0_max_vcpus; > + dom0->max_vcpus = max_vcpus; > > return alloc_vcpu(dom0, 0, 0); > } > @@ -185,11 +204,11 @@ static unsigned long __init compute_dom0_nr_pages( > unsigned long max_pages = dom0_max_nrpages; > > /* Reserve memory for further dom0 vcpu-struct allocations... */ > - avail -= (opt_dom0_max_vcpus - 1UL) > + avail -= (d->max_vcpus - 1UL) > << get_order_from_bytes(sizeof(struct vcpu)); > /* ...and compat_l4''s, if needed. */ > if ( is_pv_32on64_domain(d) ) > - avail -= opt_dom0_max_vcpus - 1; > + avail -= d->max_vcpus - 1; > > /* Reserve memory for iommu_dom0_init() (rough estimate). */ > if ( iommu_enabled ) > @@ -883,10 +902,10 @@ int __init construct_dom0( > for ( i = 0; i < XEN_LEGACY_MAX_VCPUS; i++ ) > shared_info(d, vcpu_info[i].evtchn_upcall_mask) = 1; > > - printk("Dom0 has maximum %u VCPUs\n", opt_dom0_max_vcpus); > + printk("Dom0 has maximum %u VCPUs\n", d->max_vcpus); > > cpu = cpumask_first(cpupool0->cpu_valid); > - for ( i = 1; i < opt_dom0_max_vcpus; i++ ) > + for ( i = 1; i < d->max_vcpus; i++ ) > { > cpu = cpumask_cycle(cpu, cpupool0->cpu_valid); > (void)alloc_vcpu(d, i, cpu); > -- > 1.7.2.5
David Vrabel
2012-May-08 13:58 UTC
Re: [PATCH] x86: make the dom0_max_vcpus option more flexible
On 07/05/12 09:19, Jan Beulich wrote:>> Subject: [PATCH] x86: make the dom0_max_vcpus option more flexible >> >> The dom0_max_vcpus command line option only allows the exact number of >> VCPUs for dom0 to be set. It is not possible to say "up to N VCPUs >> but no more than the number physically present." >> >> Allow a range for the option to set a minimum number of VCPUs, and a >> maximum which does not exceed the number of PCPUs. >> >> For example, with "dom0_max_vcpus=4-8": >> >> PCPUs Dom0 VCPUs >> 2 4 >> 4 4 >> 6 6 >> 8 8 >> 10 8 >> >> Existing command lines with "dom0_max_vcpus=N" still work as before. >> >> Signed-off-by: David Vrabel <david.vrabel@citrix.com> > > Acked-by: Jan Beulich <jbeulich@suse.com> > > But I''m not sure whether this qualifies for going in for 4.2...I don''t think it''s a 4.2 candidate. I posted it now we need this functionality in XenServer and I didn''t want to change the command line in a way that would be incompatible with upstream. David