On Tue, Jul 3, 2018 at 10:17 AM, Burakov, Anatoly <anatoly.bura...@intel.com
> wrote:
> On 02-Jul-18 6:27 PM, Alejandro Lucero wrote:
>
>> Linux kernel uses a really high address as starting address for
>> serving mmaps calls. If there exists addressing limitations and
>> IOVA mode is VA, this starting address is likely too high for
>> those devices. However, it is possible to use a lower address in
>> the process virtual address space as with 64 bits there is a lot
>> of available space.
>>
>> This patch adds an address hint as starting address for 64 bits
>> systems.
>>
>> Signed-off-by: Alejandro Lucero <alejandro.luc...@netronome.com>
>> ---
>>
>
> <snip>
>
>
> long aligned_addr;
>> - if (internal_config.base_virtaddr != 0) {
>> - addr = (void*) (uintptr_t) (internal_config.base_virtaddr
>> +
>> - baseaddr_offset);
>> - }
>> - else addr = NULL;
>> -
>> RTE_LOG(DEBUG, EAL, "Ask a virtual area of 0x%zx bytes\n", *size);
>> fd = open("/dev/zero", O_RDONLY);
>> @@ -278,7 +289,22 @@
>> return NULL;
>> }
>> do {
>> - addr = mmap(addr,
>> + if (internal_config.base_virtaddr != 0) {
>> + addr_hint = (void *) (uintptr_t)
>> + (internal_config.base_virtaddr +
>> + baseaddr_offset);
>> + }
>> +#ifdef RTE_ARCH_64
>> + else {
>> + addr_hint = (void *) (uintptr_t) (baseaddr +
>> + baseaddr_offset);
>> + }
>> +#else
>> + else {
>> + addr_hint = NULL;
>> + }
>> +#endif
>>
>
> If my understanding is correct, calculations are all done on static
> variables, only the result is assigned to addr_hint which is local. Can we
> move this into a function and put these #ifdefs there, while keeping this
> code clean?
Ok.
>
>
> + addr = mmap(addr_hint,
>> (*size) + hugepage_sz, PROT_READ,
>> #ifdef RTE_ARCH_PPC_64
>> MAP_PRIVATE | MAP_ANONYMOUS | MAP_HUGETLB,
>> @@ -286,8 +312,14 @@
>> MAP_PRIVATE,
>> #endif
>> fd, 0);
>> - if (addr == MAP_FAILED)
>> + if (addr == MAP_FAILED) {
>> + /* map failed. Let's try with less memory */
>> *size -= hugepage_sz;
>> + } else if (addr_hint && addr != addr_hint) {
>> + /* map not using hint. Let's try with another
>> offset */
>>
>
> Comment is slightly misleading - "map not using hint" implies we are about
> to map something without using hint. Suggested rewording:
>
> suggested address hint was not used, try with another offset
What about "hint was not used. Try with another offset" ?
By the way, I forgot to unmap the memory in this case. I will fix this in
next version.
>
>
> + addr = MAP_FAILED;
>> + baseaddr_offset += 0x100000000;
>> + }
>> } while (addr == MAP_FAILED && *size > 0);
>> if (addr == MAP_FAILED) {
>>
>>
>
> --
> Thanks,
> Anatoly
>
