From mboxrd@z Thu Jan  1 00:00:00 1970
From: Thomas Monjalon <thomas.monjalon@6wind.com>
Subject: Re: no hugepage with UIO poll-mode driver
Date: Wed, 25 Nov 2015 12:03:05 +0100
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References: <56554B08.3040400@ndsl.kaist.edu> <1711935.0QY3Nxc9zX@xps13>
 <20151125110020.GA14808@bricha3-MOBL3>
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To: Bruce Richardson <bruce.richardson@intel.com>
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2015-11-25 11:00, Bruce Richardson:
> On Wed, Nov 25, 2015 at 11:23:57AM +0100, Thomas Monjalon wrote:
> > 2015-11-25 10:08, Bruce Richardson:
> > > On Wed, Nov 25, 2015 at 03:39:17PM +0900, Younghwan Go wrote:
> > > > Hi Jianfeng,
> > > > 
> > > > Thanks for the email. rte mempool was successfully created without any
> > > > error. Now the next problem is that rte_eth_rx_burst() is always returning 0
> > > > as if there was no packet to receive... Do you have any suggestion on what
> > > > might be causing this issue? In the meantime, I will be digging through
> > > > ixgbe driver code to see what's going on.
> > > > 
> > > > Thank you,
> > > > Younghwan
> > > > 
> > > 
> > > The problem is that with --no-huge we don't have the physical address of the memory
> > > to write to the network card. That's what it's marked as for testing only.
> > 
> > Even with rte_mem_virt2phy() + rte_mem_lock_page() ?
> > 
> With no-huge, we just set up a single memory segment at startup and set its
> "physaddr" to be the virtual address.
> 
>         /* hugetlbfs can be disabled */
>         if (internal_config.no_hugetlbfs) {
>                 addr = mmap(NULL, internal_config.memory, PROT_READ | PROT_WRITE,
>                                 MAP_PRIVATE | MAP_ANONYMOUS, 0, 0);
>                 if (addr == MAP_FAILED) {
>                         RTE_LOG(ERR, EAL, "%s: mmap() failed: %s\n", __func__,
>                                         strerror(errno));
>                         return -1;
>                 }
>                 mcfg->memseg[0].phys_addr = (phys_addr_t)(uintptr_t)addr;

rte_mem_virt2phy() does not use memseg.phys_addr but /proc/self/pagemap:

    /*
     * the pfn (page frame number) are bits 0-54 (see
     * pagemap.txt in linux Documentation)
     */
    physaddr = ((page & 0x7fffffffffffffULL) * page_size)
        + ((unsigned long)virtaddr % page_size);