[PATCH] x86-64: fix page table accounting

From: Jan Beulich
Date: Thu Oct 04 2012 - 09:48:03 EST


Commit 20167d3421a089a1bf1bd680b150dc69c9506810 ("x86-64: Fix
accounting in kernel_physical_mapping_init()") went a little too far
by entirely removing the counting of pre-populated page tables: This
should be done at boot time (to cover the page tables set up in early
boot code), but shouldn't be done during memory hot add.

Hence, re-add the removed increments of "pages", but make them and the
one in phys_pte_init() conditional upon !after_bootmem.

Reported-by: Hugh Dickins <hughd@xxxxxxxxxx>
Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>

---
Not sure if this ought to be copied to stable@.

---
arch/x86/mm/init_64.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)

--- 3.6/arch/x86/mm/init_64.c
+++ 3.6-x86_64-page-table-count/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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