Messages in this thread |  | | Date | Mon, 23 Mar 2015 15:29:16 +0100 | | From | Juergen Gross <> | | Subject | Re: [Xen-devel] [Patch V2 1/2] xen: prepare p2m list for memory hotplug |
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On 03/23/2015 01:46 PM, David Vrabel wrote: > On 20/03/15 12:55, Juergen Gross wrote: >> Commit 054954eb051f35e74b75a566a96fe756015352c8 ("xen: switch to linear >> virtual mapped sparse p2m list") introduced a regression regarding to >> memory hotplug for a pv-domain: as the virtual space for the p2m list >> is allocated for the to be expected memory size of the domain only, >> hotplugged memory above that size will not be usable by the domain. >> >> Correct this by using a configurable size for the p2m list in case of >> memory hotplug enabled (default supported memory size is 512 GB for >> 64 bit domains and 4 GB for 32 bit domains). >> >> Signed-off-by: Juergen Gross <jgross@suse.com> >> --- >> arch/x86/xen/p2m.c | 10 +++++++++- >> drivers/xen/Kconfig | 14 ++++++++++++++ >> 2 files changed, 23 insertions(+), 1 deletion(-) >> >> diff --git a/arch/x86/xen/p2m.c b/arch/x86/xen/p2m.c >> index 9f93af5..b47124d 100644 >> --- a/arch/x86/xen/p2m.c >> +++ b/arch/x86/xen/p2m.c >> @@ -91,6 +91,12 @@ EXPORT_SYMBOL_GPL(xen_p2m_size); >> unsigned long xen_max_p2m_pfn __read_mostly; >> EXPORT_SYMBOL_GPL(xen_max_p2m_pfn); >> >> +#ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG_LIMIT >> +#define P2M_LIMIT CONFIG_XEN_BALLOON_MEMORY_HOTPLUG_LIMIT >> +#else >> +#define P2M_LIMIT 0 >> +#endif >> + >> static DEFINE_SPINLOCK(p2m_update_lock); >> >> static unsigned long *p2m_mid_missing_mfn; >> @@ -385,9 +391,11 @@ static void __init xen_rebuild_p2m_list(unsigned long *p2m) >> void __init xen_vmalloc_p2m_tree(void) >> { >> static struct vm_struct vm; >> + unsigned long p2m_limit; >> >> + p2m_limit = (phys_addr_t)P2M_LIMIT * 1024 * 1024 * 1024 / PAGE_SIZE; >> vm.flags = VM_ALLOC; >> - vm.size = ALIGN(sizeof(unsigned long) * xen_max_p2m_pfn, >> + vm.size = ALIGN(sizeof(unsigned long) * max(xen_max_p2m_pfn, p2m_limit), >> PMD_SIZE * PMDS_PER_MID_PAGE); >> vm_area_register_early(&vm, PMD_SIZE * PMDS_PER_MID_PAGE); >> pr_notice("p2m virtual area at %p, size is %lx\n", vm.addr, vm.size); >> diff --git a/drivers/xen/Kconfig b/drivers/xen/Kconfig >> index b812462..0f1b509 100644 >> --- a/drivers/xen/Kconfig >> +++ b/drivers/xen/Kconfig >> @@ -55,6 +55,20 @@ config XEN_BALLOON_MEMORY_HOTPLUG >> >> In that case step 3 should be omitted. >> >> +config XEN_BALLOON_MEMORY_HOTPLUG_LIMIT >> + int > > Because you've not supplied a summary for this option, it is not user > configurable. Is this intentional?
No. Sorry, I just tested it via editing .config, not using the menues. Can you add it when committing (e.g. "Upper limit in GBs a pv domain can be expanded to using memory hotplug")?
Or should I send another patch?
Juergen
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