Re: [Xen-devel] [PATCH for 2.3 v2 1/1] xen-hvm: increase maxmem before calling xc_domain_populate_physmap

[Don Slutz <dslutz@xxxxxxxxxxx>]

Ping

On 12/23/14 09:35, Don Slutz wrote:
> Ping.
> 
> On 12/03/14 08:15, Don Slutz wrote:
>> From: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
>>
>> Increase maxmem before calling xc_domain_populate_physmap_exact to
>> avoid the risk of running out of guest memory. This way we can also
>> avoid complex memory calculations in libxl at domain construction
>> time.
>>
>> This patch fixes an abort() when assigning more than 4 NICs to a VM.
>>
>> Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
>> Signed-off-by: Don Slutz <dslutz@xxxxxxxxxxx>
>> ---
>> v2: Changes by Don Slutz
>>    Switch from xc_domain_getinfo to xc_domain_getinfolist
>>    Fix error check for xc_domain_getinfolist
>>    Limit increase of maxmem to only do when needed:
>>      Add QEMU_SPARE_PAGES (How many pages to leave free)
>>      Add free_pages calculation
>>
>>   xen-hvm.c | 19 +++++++++++++++++++
>>   1 file changed, 19 insertions(+)
>>
>> diff --git a/xen-hvm.c b/xen-hvm.c
>> index 7548794..d30e77e 100644
>> --- a/xen-hvm.c
>> +++ b/xen-hvm.c
>> @@ -90,6 +90,7 @@ static inline ioreq_t
>> *xen_vcpu_ioreq(shared_iopage_t *shared_page, int vcpu)
>>   #endif
>>     #define BUFFER_IO_MAX_DELAY  100
>> +#define QEMU_SPARE_PAGES 16
>>     typedef struct XenPhysmap {
>>       hwaddr start_addr;
>> @@ -244,6 +245,8 @@ void xen_ram_alloc(ram_addr_t ram_addr, ram_addr_t
>> size, MemoryRegion *mr)
>>       unsigned long nr_pfn;
>>       xen_pfn_t *pfn_list;
>>       int i;
>> +    xc_domaininfo_t info;
>> +    unsigned long free_pages;
>>         if (runstate_check(RUN_STATE_INMIGRATE)) {
>>           /* RAM already populated in Xen */
>> @@ -266,6 +269,22 @@ void xen_ram_alloc(ram_addr_t ram_addr,
>> ram_addr_t size, MemoryRegion *mr)
>>           pfn_list[i] = (ram_addr >> TARGET_PAGE_BITS) + i;
>>       }
>>   +    if ((xc_domain_getinfolist(xen_xc, xen_domid, 1, &info) != 1) ||
>> +        (info.domain != xen_domid)) {
>> +        hw_error("xc_domain_getinfolist failed");
>> +    }
>> +    free_pages = info.max_pages - info.tot_pages;
>> +    if (free_pages > QEMU_SPARE_PAGES) {
>> +        free_pages -= QEMU_SPARE_PAGES;
>> +    } else {
>> +        free_pages = 0;
>> +    }
>> +    if ((free_pages < nr_pfn) &&
>> +        (xc_domain_setmaxmem(xen_xc, xen_domid,
>> +                             ((info.max_pages + nr_pfn - free_pages)
>> +                              << (XC_PAGE_SHIFT - 10))) < 0)) {
>> +        hw_error("xc_domain_setmaxmem failed");
>> +    }
>>       if (xc_domain_populate_physmap_exact(xen_xc, xen_domid, nr_pfn,
>> 0, 0, pfn_list)) {
>>           hw_error("xen: failed to populate ram at " RAM_ADDR_FMT,
>> ram_addr);
>>       }
> 

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