[dpdk-stable] [PATCH v2 4/6] mem: use address hint for mapping hugepages
Burakov, Anatoly
anatoly.burakov at intel.com
Tue Jul 3 14:37:08 CEST 2018
On 03-Jul-18 1:09 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.lucero at netronome.com>
> ---
<snip>
> +static void *
> +get_addr_hint(void)
> +{
> + if (internal_config.base_virtaddr != 0) {
> + return (void *) (uintptr_t)
> + (internal_config.base_virtaddr +
> + baseaddr_offset);
> + }
> +#ifdef RTE_ARCH_64
> + else {
> + return (void *) (uintptr_t) (baseaddr +
> + baseaddr_offset);
> + }
> +#else
> + else {
> + return NULL;
> + }
> +#endif
Nitpicking, but probably ifdefs should be inside else clause? Two else's
look weird.
> +}
> +
> /*
> * Try to mmap *size bytes in /dev/zero. If it is successful, return the
> * pointer to the mmap'd area and keep *size unmodified. Else, retry
> @@ -260,16 +297,10 @@
> static void *
> get_virtual_area(size_t *size, size_t hugepage_sz)
> {
<snip>
> - addr = mmap(addr,
> + addr_hint = get_addr_hint();
> +
> + addr = mmap(addr_hint,
> (*size) + hugepage_sz, PROT_READ,
> #ifdef RTE_ARCH_PPC_64
> MAP_PRIVATE | MAP_ANONYMOUS | MAP_HUGETLB,
> @@ -286,8 +319,15 @@
> 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) {
> + /* hint was not used. Try with another offset */
> + munmap(addr, (*size) + hugepage_sz);
Maybe store mapping size in a variable.
Otherwise,
Acked-by: Anatoly Burakov <anatoly.burakov at intel.com>
--
Thanks,
Anatoly
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