>>> On 01.10.12 at 10:37, Hugh Dickins <[email protected]> wrote:
> I noticed yesterday that the DirectMap counts at the bottom of x86_64's
> /proc/meminfo are wrong on v3.5 and v3.6. For example, I happen to have
> booted this laptop with mem=700M to run a test, but /proc/meminfo shows
>
> DirectMap4k: 4096 kB
> DirectMap2M: 18446744073709547520 kB
I cannot see such odd effect with "mem="; with I can (for any
value up to around 1G).
> Or if I boot with the full amount of physical memory, the DirectMap
> numbers do not add up to the full amount of physical memory, as they
> used to do on v3.4 and before.
That one I can see how could have happened, in that said patch
went a little too far: Dropping the "pages" increments from
phys_p[um]d_init() is necessary only for the hotplug case (as
otherwise duplicating accounting already done earlier), while
at boot time we would want to do the accounting.
> Whilst I've not yet tried reverting it, I strongly suspect your
> 20167d3421a0 "x86-64: Fix accounting in kernel_physical_mapping_init()".
>
> Either it was a complete misunderstanding, totally bogus, and should
> simply be reverted; or perhaps you really noticed something wrong in
> your code inspection, but didn't get the fix quite right?
The latter, apparently. The patch below should fix both aspects.
Jan
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -386,7 +386,8 @@ phys_pte_init(pte_t *pte_page, unsigned
* these mappings are more intelligent.
*/
if (pte_val(*pte)) {
- pages++;
+ if (!after_bootmem)
+ pages++;
continue;
}
@@ -451,6 +452,8 @@ phys_pmd_init(pmd_t *pmd_page, unsigned
* attributes.
*/
if (page_size_mask & (1 << PG_LEVEL_2M)) {
+ if (!after_bootmem)
+ pages++;
last_map_addr = next;
continue;
}
@@ -526,6 +529,8 @@ phys_pud_init(pud_t *pud_page, unsigned
* attributes.
*/
if (page_size_mask & (1 << PG_LEVEL_1G)) {
+ if (!after_bootmem)
+ pages++;
last_map_addr = next;
continue;
}
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