2009-10-07 12:46:00

by Jan Beulich

Subject: [PATCH] adjust gfp mask passed on nested vmalloc() invocation (v2)

- avoid wasting more precious resources (DMA or DMA32 pools), when
being called through vmalloc_32{,_user}()
- explicitly allow using high memory here even if the outer allocation
request doesn't allow it, unless is collides with __GFP_ZERO

Signed-off-by: Jan Beulich <[email protected]>
Cc: Hugh Dickins <[email protected]>

---
mm/vmalloc.c | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)

--- linux-2.6.32-rc3/mm/vmalloc.c 2009-10-05 11:59:56.000000000 +0200
+++ 2.6.32-rc3-vmalloc-nested-gfp/mm/vmalloc.c 2009-10-07 14:39:38.000000000 +0200
@@ -1410,6 +1410,7 @@ static void *__vmalloc_area_node(struct
{
struct page **pages;
unsigned int nr_pages, array_size, i;
+ gfp_t nested_gfp = (gfp_mask & GFP_RECLAIM_MASK) | __GFP_ZERO;

nr_pages = (area->size - PAGE_SIZE) >> PAGE_SHIFT;
array_size = (nr_pages * sizeof(struct page *));
@@ -1417,13 +1418,11 @@ static void *__vmalloc_area_node(struct
area->nr_pages = nr_pages;
/* Please note that the recursion is strictly bounded. */
if (array_size > PAGE_SIZE) {
- pages = __vmalloc_node(array_size, gfp_mask | __GFP_ZERO,
+ pages = __vmalloc_node(array_size, nested_gfp | __GFP_HIGHMEM,
PAGE_KERNEL, node, caller);
area->flags |= VM_VPAGES;
} else {
- pages = kmalloc_node(array_size,
- (gfp_mask & GFP_RECLAIM_MASK) | __GFP_ZERO,
- node);
+ pages = kmalloc_node(array_size, nested_gfp, node);
}
area->pages = pages;
area->caller = caller;

2009-10-07 13:56:30

by Hugh Dickins

Subject: Re: [PATCH] adjust gfp mask passed on nested vmalloc() invocation (v2)

On Wed, 7 Oct 2009, Jan Beulich wrote:

> - avoid wasting more precious resources (DMA or DMA32 pools), when
> being called through vmalloc_32{,_user}()
> - explicitly allow using high memory here even if the outer allocation
> request doesn't allow it, unless is collides with __GFP_ZERO
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
that's no longer an issue in the patch
>
> Signed-off-by: Jan Beulich <[email protected]>
> Cc: Hugh Dickins <[email protected]>

The patch looks good to me now, much nicer, thanks:
Acked-by: Hugh Dickins <[email protected]>

>
> ---
> mm/vmalloc.c | 7 +++----
> 1 file changed, 3 insertions(+), 4 deletions(-)
>
> --- linux-2.6.32-rc3/mm/vmalloc.c 2009-10-05 11:59:56.000000000 +0200
> +++ 2.6.32-rc3-vmalloc-nested-gfp/mm/vmalloc.c 2009-10-07 14:39:38.000000000 +0200
> @@ -1410,6 +1410,7 @@ static void *__vmalloc_area_node(struct
> {
> struct page **pages;
> unsigned int nr_pages, array_size, i;
> + gfp_t nested_gfp = (gfp_mask & GFP_RECLAIM_MASK) | __GFP_ZERO;
>
> nr_pages = (area->size - PAGE_SIZE) >> PAGE_SHIFT;
> array_size = (nr_pages * sizeof(struct page *));
> @@ -1417,13 +1418,11 @@ static void *__vmalloc_area_node(struct
> area->nr_pages = nr_pages;
> /* Please note that the recursion is strictly bounded. */
> if (array_size > PAGE_SIZE) {
> - pages = __vmalloc_node(array_size, gfp_mask | __GFP_ZERO,
> + pages = __vmalloc_node(array_size, nested_gfp | __GFP_HIGHMEM,
> PAGE_KERNEL, node, caller);
> area->flags |= VM_VPAGES;
> } else {
> - pages = kmalloc_node(array_size,
> - (gfp_mask & GFP_RECLAIM_MASK) | __GFP_ZERO,
> - node);
> + pages = kmalloc_node(array_size, nested_gfp, node);
> }
> area->pages = pages;
> area->caller = caller;

2009-10-07 14:27:01

by Jan Beulich

Subject: Re: [PATCH] adjust gfp mask passed on nested vmalloc() invocation (v2)

>>> Hugh Dickins <[email protected]> 07.10.09 15:55 >>>
>On Wed, 7 Oct 2009, Jan Beulich wrote:
>
>> - avoid wasting more precious resources (DMA or DMA32 pools), when
>> being called through vmalloc_32{,_user}()
>> - explicitly allow using high memory here even if the outer allocation
>> request doesn't allow it, unless is collides with __GFP_ZERO
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> that's no longer an issue in the patch

Oops. Will send out a corrected version in a second.

Jan