Re: [Qemu-devel] [PATCH v4 1/2] hw/acpi-build: Fix SRAT memory building when there is no memory in node0

[Dou Liyang]

Hi Eduardo,

At 08/31/2017 06:38 PM, Dou Liyang wrote:

Hi Eduardo,

[...]

+            continue;
         }

Now the nodes will be out of order, if node 0 has no RAM.  Why?

Because the code parsed the other node with RAM first, then parsed the
node 0.

Why not implement this in the same way the PCI 4GB hole is
already implemented.  e.g.:

Indeed, it is better and more refined. I will do it in the next version.

#define HOLE_640K_START  (640 * 1024)
#define HOLE_640K_END   (1024 * 1024)

    for (node = 0; node < pcms->numa_nodes; node++) {
        mem_base = next_base;
        mem_len = pcms->node_mem[node];
        next_base = mem_base + mem_len;

        /* Cut out the 640K hole */
        if (mem_base <= HOLE_640K_START &&
            next_base > HOLE_640K_START) {
            mem_len -= next_base - HOLE_640K;
            if (mem_len > 0) {
                numamem = acpi_data_push(table_data, sizeof *numamem);
                build_srat_memory(numamem, mem_base, mem_len, node,
                                  MEM_AFFINITY_ENABLED);
            }
            mem_base = HOLE_640K_END;
            /* ... */

BTW, in case

   0
   |-----------|-------|--------|-------
   |           |       |        |
mem_base      640K   next_base   1M


 I wanna add a check here,

            /* Check for the rare case: 640K < RAM < 1M */
            if (next_base <= HOLE_640K_END) {
                next_base = HOLE_640K_END;
                continue;
            }
            mem_base = HOLE_640K_END;
            mem_len = next_base - HOLE_640K_END;

I guess no one would set a node with this less RAM,
So, Is that necessary?

I post the V5 patches, and use your code.

It may be not very clearly, for the detail, Please see the new version.

Thanks,
        dou.

Thanks,
    dou.

        }
        /* Cut out the ACPI_PCI hole */
        if (mem_base <= pcms->below_4g_mem_size &&
            next_base > pcms->below_4g_mem_size) {
            mem_len -= next_base - pcms->below_4g_mem_size;
            /* ... *]
        }
        numamem = acpi_data_push(table_data, sizeof *numamem);
        build_srat_memory(numamem, mem_base, mem_len, node,
                          MEM_AFFINITY_ENABLED);
        /* ... */
    }

-        numamem = acpi_data_push(table_data, sizeof *numamem);
-        build_srat_memory(numamem, mem_base, mem_len, i - 1,
-                          MEM_AFFINITY_ENABLED);
+        mem_base = build_srat_node_entry(table_data, pcms, i,
+                                            mem_base,
pcms->node_mem[i]);
     }
     slots = (table_data->len - numa_start) / sizeof *numamem;
     for (; slots < pcms->numa_nodes + 2; slots++) {
--
2.5.5