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Subject[PATCH 6/6] mm: remove vmalloc_sync_all() from alloc_vm_area()
Date
From: David Vrabel <david.vrabel@citrix.com>

The address space allocated by the remaining user of alloc_vm_area()
is not accessed during a hypercall. Therefore, the normal mechanism
of populating the vmalloc page tables during a fault works so the
vmalloc_sync_all() is not required and it can be removed.

Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
---
mm/vmalloc.c | 12 +-----------
1 files changed, 1 insertions(+), 11 deletions(-)

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 5016f19..b0b4550 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -2117,9 +2117,7 @@ static int f(pte_t *pte, pgtable_t table, unsigned long addr, void *data)
*
* This function reserves a range of kernel address space, and
* allocates pagetables to map that range. No actual mappings
- * are created. If the kernel address space is not shared
- * between processes, it syncs the pagetable across all
- * processes.
+ * are created.
*/
struct vm_struct *alloc_vm_area(size_t size)
{
@@ -2140,14 +2138,6 @@ struct vm_struct *alloc_vm_area(size_t size)
return NULL;
}

- /*
- * If the allocated address space is passed to a hypercall
- * before being used then we cannot rely on a page fault to
- * trigger an update of the page tables. So sync all the page
- * tables here.
- */
- vmalloc_sync_all();
-
return area;
}
EXPORT_SYMBOL_GPL(alloc_vm_area);
--
1.7.2.5


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