On 11/27/2012 06:00 PM, Wen Congyang wrote:
For hot removing memory, we sholud remove page table about the memory.
So the patch searches a page table about the removed memory, and clear
page table.
(snip)
+void __meminit
+kernel_physical_mapping_remove(unsigned long start, unsigned long end)
+{
+ unsigned long next;
+ bool pgd_changed = false;
+
+ start = (unsigned long)__va(start);
+ end = (unsigned long)__va(end);
Hi Wu,
Here, you expect start and end are physical addresses. But in
phys_xxx_remove() function, I think using virtual addresses is just
fine. Functions like pmd_addr_end() and pud_index() only calculate
an offset.
So, would you please tell me if we have to use physical addresses here ?
Thanks. :)
+
+ for (; start< end; start = next) {
+ pgd_t *pgd = pgd_offset_k(start);
+ pud_t *pud;
+
+ next = pgd_addr_end(start, end);
+
+ if (!pgd_present(*pgd))
+ continue;
+
+ pud = map_low_page((pud_t *)pgd_page_vaddr(*pgd));
+ phys_pud_remove(pud, __pa(start), __pa(next));
+ if (free_pud_table(pud, pgd))
+ pgd_changed = true;
+ unmap_low_page(pud);
+ }
+
+ if (pgd_changed)
+ sync_global_pgds(start, end - 1);
+
+ flush_tlb_all();
+}
+
#ifdef CONFIG_MEMORY_HOTREMOVE
int __ref arch_remove_memory(u64 start, u64 size)
{
@@ -692,6 +921,8 @@ int __ref arch_remove_memory(u64 start, u64 size)
ret = __remove_pages(zone, start_pfn, nr_pages);
WARN_ON_ONCE(ret);
+ kernel_physical_mapping_remove(start, start + size);
+
return ret;
}
#endif
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