[PATCH] Optimize relay_alloc_page_array() slightly by using vzallocrather than vmalloc and memset

From: Jesper Juhl
Date: Sat Oct 30 2010 - 16:36:58 EST


Hi,

We can optimize kernel/relay.c::relay_alloc_page_array() slightly by using
vzalloc. The patch makes these changes:

- use vzalloc instead of vmalloc+memset.
- remove redundant local variable 'array'.
- declare local 'pa_size' as const.

Cuts down nicely on both source and object-code size.


Signed-off-by: Jesper Juhl <jj@xxxxxxxxxxxxx>
---
Compile tested only.

relay.c | 15 ++++-----------
1 file changed, 4 insertions(+), 11 deletions(-)

diff --git a/kernel/relay.c b/kernel/relay.c
index c7cf397..859ea5a 100644
--- a/kernel/relay.c
+++ b/kernel/relay.c
@@ -70,17 +70,10 @@ static const struct vm_operations_struct relay_file_mmap_ops = {
*/
static struct page **relay_alloc_page_array(unsigned int n_pages)
{
- struct page **array;
- size_t pa_size = n_pages * sizeof(struct page *);
-
- if (pa_size > PAGE_SIZE) {
- array = vmalloc(pa_size);
- if (array)
- memset(array, 0, pa_size);
- } else {
- array = kzalloc(pa_size, GFP_KERNEL);
- }
- return array;
+ const size_t pa_size = n_pages * sizeof(struct page *);
+ if (pa_size > PAGE_SIZE)
+ return vzalloc(pa_size);
+ return kzalloc(pa_size, GFP_KERNEL);
}

/*



--
Jesper Juhl <jj@xxxxxxxxxxxxx> http://www.chaosbits.net/
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