2012-10-22 12:04:43

by Ezequiel Garcia

Subject: [PATCH 2/2] mm/slob: Use free_page instead of put_page for page-size kmalloc allocations

When freeing objects, the slob allocator currently free empty pages
calling __free_pages(). However, page-size kmallocs are disposed
using put_page() instead.

It makes no sense to call put_page() for kernel pages that are provided
by the object allocator, so we shouldn't be doing this ourselves.

This is based on:
commit d9b7f22623b5fa9cc189581dcdfb2ac605933bf4
Author: Glauber Costa <[email protected]>
slub: use free_page instead of put_page for freeing kmalloc allocation

Cc: Christoph Lameter <[email protected]>
Cc: Pekka Enberg <[email protected]>
Cc: Matt Mackall <[email protected]>
Cc: Glauber Costa <[email protected]>
Signed-off-by: Ezequiel Garcia <[email protected]>
---
mm/slob.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/mm/slob.c b/mm/slob.c
index a65e802..362632d 100644
--- a/mm/slob.c
+++ b/mm/slob.c
@@ -506,7 +506,7 @@ void kfree(const void *block)
unsigned int *m = (unsigned int *)(block - align);
slob_free(m, *m + align);
} else
- put_page(sp);
+ __free_pages(sp, compound_order(sp));
}
EXPORT_SYMBOL(kfree);

--
1.7.8.6

2012-10-22 12:07:54

by Glauber Costa

Subject: Re: [PATCH 2/2] mm/slob: Use free_page instead of put_page for page-size kmalloc allocations

On 10/22/2012 04:04 PM, Ezequiel Garcia wrote:
> When freeing objects, the slob allocator currently free empty pages
> calling __free_pages(). However, page-size kmallocs are disposed
> using put_page() instead.
>
> It makes no sense to call put_page() for kernel pages that are provided
> by the object allocator, so we shouldn't be doing this ourselves.
>
> This is based on:
> commit d9b7f22623b5fa9cc189581dcdfb2ac605933bf4
> Author: Glauber Costa <[email protected]>
Acked-by: Glauber Costa <[email protected]>

2012-10-31 06:56:20

by Pekka Enberg

Subject: Re: [PATCH 2/2] mm/slob: Use free_page instead of put_page for page-size kmalloc allocations

> On 10/22/2012 04:04 PM, Ezequiel Garcia wrote:
>> When freeing objects, the slob allocator currently free empty pages
>> calling __free_pages(). However, page-size kmallocs are disposed
>> using put_page() instead.
>>
>> It makes no sense to call put_page() for kernel pages that are provided
>> by the object allocator, so we shouldn't be doing this ourselves.
>>
>> This is based on:
>> commit d9b7f22623b5fa9cc189581dcdfb2ac605933bf4
>> Author: Glauber Costa <[email protected]>

On Mon, Oct 22, 2012 at 3:07 PM, Glauber Costa <[email protected]> wrote:
> Acked-by: Glauber Costa <[email protected]>

Applied, thanks Ezequiel!